DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on May 5, 2026 has been entered.
Claim Objections
Claim(s) 1-2-3, 5, 11-19 is/are objected to because of the following informalities:
With respect to claim 1, “layer first” recited in line 15 of the claim should read “first layer’. Claims 2-3, 5, 11-19 which either directly or indirectly depend from claim 1 and which inherit issue of claim 1 are objected to for similar reason.
With respect to claim 12, “the first layer formed” recited in line 1 of the claim should read “the first layer is formed”.
Appropriate correction is required.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claim(s) 1, 2, 5, 12-13, 15 and 17 is/are rejected under 35 U.S.C. 103 as being unpatentable over Savant et al. (US 2020/0135915, hereinafter “Savant”, previously cited) in view of Hsueh et al. (US 2014/0103284, hereinafter “Hsueh”, previously cited), Wang (US 9,142,764, hereinafter “Wang”, previously cited), Takahashi et al. (US 2020/0063258, hereinafter “Takahashi”, previously cited), Arimura et al. (US 2017/0162686, hereinafter “Arimura”, previously cited), Horii et al. (US 2015/0171179, hereinafter “Horii”, previously cited), Yang et al. (US 2014/0209976, hereinafter “Yang”, previously cited), Arita et al. (US 2011/0002155, hereinafter “Arita”, previously cited), and Bilodeau et al. (US 2018/0337253, hereinafter “Bilodeau”), with Smith et al. (US 9,911,595, hereinafter “Smith”, previously cited) relied upon for showing that ALD is a self-limiting process.
Regarding claim 1, Savant teaches in Figs. 1A-1B (shown below) and related text a method of forming a structure including a silicon nitride layer, the method comprising the steps of:
providing a substrate (10, Fig. 1A and ¶[0044]) comprising a surface (Fig. 1A), wherein the surface comprises a material comprising one or more of silicon, germanium, germanium oxide, germanium tin, silicon germanium, silicon germanium tin, silicon carbide, or a group III-V semiconductor material (¶[0044] and Embodiment 1, Fig. 2 of provisional application), and further comprising a high dielectric constant material (82, Fig. 1A and ¶[0044]) overlying and in contact with a passivation layer (Savant, 81, Fig. 1A and ¶[0063]) disposed on the surface (i.e. the high dielectric constant material 82 disclosed by Savant is overlying and in contact with passivation layer 81, Fig. 1A and ¶¶[0044] or [0063]) in a reaction chamber (¶0063]);
with the reaction chamber at a temperature (¶[0065]) depositing a first layer comprising titanium nitride (83, Fig. 1A and ¶¶[0026] and [0063]-[0064]) overlying and in contact with the high dielectric constant material (Fig. 1A); and
with the reaction chamber at about the temperature (¶[0065]), depositing a second layer consisting of silicon nitride (84, Fig. 1A and ¶¶[0027] and [0063]-[0064]) overlying and in contact with the first layer (Fig. 1A),
wherein the step of depositing the second layer is self-limiting (¶[0064] and ¶[0023] of provisional application, i.e. it is noted that the ALD technique used to deposit silicon nitride layer disclosed by Savant is a self-limiting by definition as evidenced by Smith, col. 4, ll. 8-19), at a thickness of 1Å to 300Å (¶[0035] and [0021] provisional application), which is overlapping the claimed range of less than about 2 Angstroms, where it would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to adjust the range of Savant to include the claimed range as a routine skill in the art to discover the optimum and/or workable range. See MPEP § 2144.05 for overlap of ranges, and
wherein the second layer has a formula of SiNx where x is about 1.2 to about 1.4 (¶[0031] and [0021] of the provisional application, e.g. x=1.22, which falls between about 1.2 and about 1.4, in SiNx when x=0.45, y=0 and z=0.55 in SixTiyNz disclosed by Savant). Alternatively, assuming that Savant does not explicitly teach SiNx layer where x is about 1.2 to about 1.4, forming silicon nitride layer with the different ratio of nitrogen would have been within the capabilities of one of ordinary skill in the art as it would amount to nothing other than changing flow ratio of nitrogen gas in order to produce silicon nitride layer that meets specific design requirements, as evidenced by Arita (Fig. 3 and ¶[0104]).
Accordingly, since the prior art teaches all of the claimed elements using such elements would lead to predictable results, and as such, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention, absent of any unexpected results or criticality thereof, to form the silicon nitride layer disclosed by Savant with the formula of SiNx where x is about 1.2 to about 1.4 as doing so would amount to nothing more than changing flow ratio of nitrogen gas in order to produce silicon nitride layer that meets specific design requirements.
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Savant, however, does not explicitly teach in the provisional application that the step of depositing the first layer and the step of depositing the second layer comprising are performed within the same reaction chamber with the temperature in the reaction chamber during the step of depositing the second layer being at about the temperature used during the step of depositing the first layer and that the titanium nitride layer further comprises a dopant selected from the group consisting of aluminum, tantalum, lanthanum, hafnium, and tungsten. Savant, also does not explicitly teach that the passivation layer comprises a thin layer of silicon with a silicon oxide cap, that the high dielectric constant material comprises one or more of lanthanum silicate and aluminum silicate and that the second layer consist of silicon nitride and impurities of carbon, hydrogen and chlorine.
To begin with, Savant teaches in the non-provisional application that the steps of depositing the first and second layers (i.e. layers comprising titanium nitride and silicon nitride) can be performed within the same reaction chamber (¶[0064]), which is consistent with the teaching of Hsueh, Wang and Takahashi, who all disclose that titanium nitride and the silicon nitride layers can be formed within the same reaction chamber (Hsueh, 502, Fig. 5 and ¶¶[0070]-[0071], [0076] and [0080]-[0081], Wang, col. 6, ll. 13-56, col. 11. 52-63 and col. 12, ll. 28-65 and Takahashi, Fig. 2 and ¶[0053]) in order to prevent wafer contamination and/or oxidation of previously formed layers, reduce processing cost and increase processing speed (Wang, col 6, ll. 23-30 and Savant, ¶¶[0034]-[0035]). Moreover, Hsueh and Takahashi also teach that the reaction chamber during the steps of depositing layers comprises titanium nitride and silicon nitride be at about the same temperature during the two steps (Hsueh, ¶[0076] and Takahashi, ¶¶[0053] and [0071]).
Thus, since the prior art teaches all of the claimed method steps, executing such steps would lead to predictable results, and as such, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to deposit both the first and the second layers in the same reaction chamber at about the same temperature based on the teaching of Hsueh, Wang and Takahashi, as such steps are well-known in the art and would prevent wafer contamination and/or oxidation of previously formed layers, reduce processing cost and increase processing speed. Additionally, it is noted that forming the first and second layers (i.e. titanium nitride and silicon nitride layers) within the same reaction chamber at the same chamber temperature, absent of any showing of unexpected results or criticality would have been obvious to one of ordinary skill in the art as it would amount to nothing more than selecting an optimum temperature by routine experimentation from the temperature range disclosed by Hsueh, Wang, and Takahashi.
Moreover, using one or more of lanthanum silicate and aluminum silicate, for the high dielectric constant material disclosed by Savant, Hsueh, Wang and Takahashi would have been obvious to one of ordinary skill in the art as evidenced by Arimura, as it would amount to nothing other than selecting a known material based on its suitability for its intended use. Specifically, Arimura, in a similar field of endeavor, teaches in Figs. 1 and 3 and related text, that lanthanum silicate (i.e. LaSiO, ¶[0070]) is a known high dielectric constant gate dielectric materials (Figs. 1, 3 and ¶[0070]) that can be used when forming a semiconductor structure similar that that disclosed by Savant, Hsueh, Wang and Takahashi.
Thus, since the prior art discloses all of the claimed elements, the results would be predictable to one of ordinary skill in the art, and as such, it would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the invention pertains to use lanthanum silicate, as disclosed by Arimura, for the high dielectric constant material disclosed by Savant, Hsueh, Wang and Takahashi as doing so would amount to nothing more than selecting a known material based on for its suitability for its intended use.
In addition, Horii in a similar field of endeavor, teaches that a first layer (titanium nitride layer), such as that disclosed by the combined teaching of Savant, Hsueh, Wang, Takahashi and Arimura or further in combination with Arita, may include dopant such as aluminum (Al), tantalum (Ta), and hafnium (Hf) (¶¶[0233] and [0236]) in order to form TiN with desired characteristics, such as resistivity or work function properties.
Thus, since the prior art discloses all of the claimed elements, the results would be predictable to one of ordinary skill in the art, and as such it would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the invention pertains to dope the first layer (titanium nitride layer) aluminum, tantalum, or hafnium in order to obtain TiN film with desired characteristics.
Furthermore, Yang in a similar field of endeavor teaches that a passivation layer disclosed by Savant, Hsueh, Wang, Takahashi, Arimura and Horii or further in combination with Arita may include a thin layer of silicon with a silicon oxide cap disposed thereon in order to improve an interfacial property between the channel layer of a transistor and the gate insulation layer pattern (¶[0094]).
Thus, since the prior art discloses all of the claimed elements, the results would be predictable to one of ordinary skill in the art, and as such it would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the invention pertains to include a thin layer of silicon with a silicon oxide cap disposed thereon as disclosed by Yang, as part of the passivation layer disclosed by the combined teaching of Savant, Hsueh, Wang, Takahashi, Arimura and Horii or further in combination with Arita in order to improve an interfacial property between the channel layer of a transistor and the gate insulation layer pattern.
Lastly, Bilodeau, in a similar field of endeavor, teaches that a layer of silicon nitride (second layer) is known in the art as corresponding to a pure silicon nitride, as well, as impure silicon nitride that includes hydrogen, carbon and/or oxygen impurities in the crystal structure (¶[0025]) depending on the precursors or the process used to form the silicon nitride layer.
Accordingly, it would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the invention pertains to have impurities of carbon, hydrogen, and chlorine in the silicon nitride layer disclosed by the combined teaching of Savant, Hsueh, Wang, Takahashi, Arimura, Horii and Arita, as such layer is known in the art as including both the pure and impure silicon forms depending on the precursors or process used to form the silicon nitride layer.
Regarding claim 2 (1), the combined teaching of Savant, Hsueh, Wang, Takahashi, Arimura, Horii, and Bilodeau, or further Arita discloses wherein the first layer (i.e. titanium nitride) has a thickness greater than 20 Angstroms (i.e. Savant teaches in ¶[0026] and ¶[0021] of provisional application that TiN is in a range from 3 Angstroms to 300 Angstroms, which is overlapping the claimed range of greater than 20 Angstroms, where it would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to adjust the range of Savant to include the claimed range as a routine skill in the art to discover the optimum and/or workable range. See MPEP § 2144.05 for overlap of ranges).
While Savant, Hsueh, Wang, Takahashi, Arimura, Horii, Arita and Bilodeau, or further Ariat do not explicitly teach wherein the second layer has a thickness less than 1 Angstrom, Savant teaches that SiN is in a range from 1 Angstrom to 300 Angstroms (¶¶[0035] and [0021] of provisional application), which is close to the claimed range of less than 1 Angstrom, where it would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to adjust the range of Savant to include the claimed range as a routine skill in the art to discover the optimum and/or workable range. See MPEP § 2144.05 for overlap of ranges (it is noted that the claimed thickness of less than 1 angstrom for the second layer appears to be less than a thickness of a monolayer (single layer) of the SiN in which a typical Si-N bond length is around 1.7 angstroms, resulting in the claimed second layer of less than a single layer of SiN).
Regarding claim 5 (1), the combined teaching of Savant, Hsueh, Wang, Takahashi, Arimura, Horii, Yang, and Bilodeau, or further Arita discloses depositing the first layer between about 350°C to about 450°C (Takahashi, ¶¶[0053]-[0054]), which is overlapping the claimed range of between about 450°C and about 600°C, where it would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to adjust the range of Takahashi to include the claimed range as a routine skill in the art to discover the optimum and/or workable range. See MPEP § 2144.05 for overlap of ranges.
Regarding claims 12 (1) and 13 (1), the combined teaching of Savant, Hsueh, Wang, Takahashi, Arimura, Horii, Yang, and Bilodeau, or further Arita was discussed above in the rejection of claim 1. The combined teaching of Savant, Hsueh, Wang, Takahashi, Arimura, Horii, Yang, and Bilodeau, or further Arita, however, does not explicitly teach that the first layer is formed where Ti has an oxidation state of +IV, as required by claim 12 or +II, as required by claim 13. Nonetheless, since Savant, Hsueh, Wang, Takahashi, Arimura, Horii, Yang, and Bilodeau, or further Arita teach the same methods steps (conditions) for forming the first layer and the same dopants, Ti would have the claimed oxidation states.
Regarding claim 15 (1), the combined teaching of Savant, Hsueh, Wang, Takahashi, Arimura, Horii, Yang, and Bilodeau, or further in combination with Arita, discloses wherein the first layer (titanium nitride) has a thickness greater than about 50 Angstroms (i.e. Savant teaches in ¶[0026] and ¶[0021] of provisional application that TiN is in a range from 3 Angstroms to 300 Angstroms, which is overlapping the claimed range of greater than 50 Angstroms, where it would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to adjust the range of Savant to include the claimed range as a routine skill in the art to discover the optimum and/or workable range. See MPEP § 2144.05 for overlap of ranges).
Regarding claim 17, the combined teaching of Savant, Hsueh, Wang, Takahashi, Arimura, Horii, Yang, and Bilodeau, or further in combination with Arita, discloses a structure formed according to the method of claim 1 as discussed above (Savant, Fig. 1A). Furthermore, it is noted that the claim is product-by-process claim, and therefore is treated according to MPEP § 2113, which states that “even though product-by-process claims are limited by and defined by the process, determination of patentability is based on the product itself.” The patentability of a product does not depend on its method of production. Since Savant, Hsueh, Wang, Takahashi, Arimura, Horii, and Yang, or further Arita teach all the structure, the claimed method does not distinguish it from the prior art.
Claim(s) 3 is/are rejected under 35 U.S.C. 103 as being unpatentable Savant, Hsueh, Wang, Takahashi, Arimura, Horii, Yang, and Bilodeau, or further Arita, as applied to claim 1 above, and further in view of Lei et al. (US 2019/0085451, hereinafter “Lei”, previously cited).
Regarding claim 3 (1), the combined teaching of Savant, Hsueh, Wang, Takahashi, Arimura, Horii, Yang, and Bilodeau, or further Ariat was discussed above in the rejection of claim 1. Savant, Hsueh, Wang, Takahashi, Arimura, Horii, Yang, and Bilodeau, or further Arita however, do not explicitly teach an in-situ hydrogen plasma treatment being performed after the step of depositing the second layer (silicon nitride) and before repeating a step of depositing a first layer (titanium nitride).
Lei, in a similar field of endeavor, teaches performing hydrogen plasma treatment after the step of depositing a silicon nitride layer (second layer) in order to affect one or more properties of the silicon nitride layer so that they meet specific design requirement (¶[0109]).
Thus, since the prior art discloses all of the method steps, using such steps would lead to predictable result, and, as such, one of ordinary skill in the art would have found it obvious, before the effective filing date of the claimed invention, to perform hydrogen treatment after the step of depositing a silicon nitride layer (second layer) as disclosed by Lei in the method disclosed by the combined teaching of Savant, Hsueh, Wang, Takahashi, Arimura, Horii, Yang, and Bilodeau or further Arita in order to affect one or more properties of the silicon nitride layer so that they meet specific design requirement. It is noted that the hydrogen plasma treatment disclosed by Savant is performed in-situ in a similar manner that applicant’s hydrogen plasma treatment is performed in-situ. Specifically, similar to the applicant, Lei teaches that hydrogen plasma treatment of the silicon nitride layer is performed after the silicon nitride layer is deposited using a plasma apparatus.
Claim(s) 11 is/are rejected under 35 U.S.C. 103 as being unpatentable over Savant, Hsueh, Wang, Takahashi, Arimura, Horri, Yang, and Bilodeau or further Arita, as applied to claim 1 above, and further in view of Rocklein et al. (US 2019/0267383, hereinafter “Rocklein”, previously cited).
Regarding claim 11 (1), the combined teaching of Savant, Hsueh, Wang, Takahashi, Arimura, Horri, Yang and Bilodeau, or further in combination with Arita, was discussed above and includes wherein the step of depositing the first layer (titanium nitride) comprises exposing the substrate to a titanium precursor, a nitrogen reactant, and a dopant precursor, wherein the dopant precursor is co-flowed into the reaction chamber with the titanium precursor (Horii, ¶¶[0081], and [0233]-[0239]). Savant, Hsueh, Wang, Takahashi, Arimura, Horii, Yang, and Bilodeau, or further Arita, however, do not explicitly teach that the layer comprising titanium nitride has a dopant atomic precent from about 2 at% to 15 at%.
Rocklein, in a similar field of endeavor, teaches that titanium nitride can be doped with aluminum, hafnium or tungsten at 0.1 atomic % (at%) to about 25 a %, such as from about 0.1 at% to about 15 at%, from about 0.1 at% to about 10 at%, or from about 1 at% to about 5 at% (¶[0036]), which either fully encompasses or overlaps the claimed range of from about 5 at% to 10 at%, in order to form titanium nitride with desired characteristics, such as resistivity or work function properties, that meet specific design requirements. Moreover, since Horri teaches that TiN doped with aluminum, hafnium and tantalum, are art recognized equivalents (¶¶[0234]-[0236]) that can be used in depending on conductivity requirements for the material, doping TiN with tantalum at atomic percent disclosed by Rocklein would have been obvious to one of ordinary skill in the art as it would amount to nothing other than adding an equivalent dopant at same percentage in order to meet specific design requirements.
Thus, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to adjust the range of Rocklein to the claimed range, and use tantalum as a dopant, as doing so would require a routine skill in the art to discover the optimum and/or workable range (see MPEP § 2144.05 for overlap of ranges) and would allow to meet specific conductivity requirements for the material.
Claim(s) 14 and 18-19 is/are rejected under 35 U.S.C. 103 as being unpatentable over Savant, Hsueh, Wang, Takahashi, Arimura, Horii, Yang, and Bilodeau, or further Arita, as applied to claims 1 and 17 above, and further in view of Chen et al. (US 2011/0233679, hereinafter “Chen”, previously cited).
Regarding claim 14 (1), the combined teaching of Savant, Hsueh, Wang, Takahashi, Arimura, Horii and Yang, or further in combination with Arita, was discussed above and further discloses a step of forming the passivation layer (Savant, 81, Fig. 1A and ¶[0025]) between silicon channel region (Savant, 20, Fig. 1A and Figs. 2 and 3 of provisional application) and the high dielectric constant material (Savant, 82, Fig. 1A). While Savant does not explicitly teach in the provisional application that the channel region includes silicon germanium, using silicon germanium in place of silicon for a channel region would have been obvious to one of ordinary skill in the art as such materials are art equivalent substrate/channel materials, as disclosed in more detail in Savant’s non-provisional application (Savant, Fig. 1A and ¶[0044]), as well as other prior art, including to Chen (Fig. 1B and ¶[0016]). Specifically, Chen, similarly to Savant’s non-provisional application, discloses that Si and SiGe are art recognized equivalent substrate/fin materials that can be used in order to meet specific design requirements for a semiconductor device.
Accordingly, since the prior art teaches all of the claimed elements, using such elements would lead to predictable results and as such it would have been obvious to one of ordinary skill in the art before the effective filing date of the claim invention to substitute SiGe for Si when forming a structure disclosed by combined teaching of Savant, Hsueh, Wang, Takahashi, Arimura, Horii, Yang, and Bilodeau, or further in combination with Arita, in order to form a structure with desired characteristics.
Regarding claim 18 (17), the combined teaching of Savant, Hsueh, Wang, Takahashi, Arimura, Horii, Yang, and Bilodeau or further in combination with Arita, was discussed above in the rejection of claim 17. While Savant does not explicitly teach in the provisional application that the channel region includes silicon germanium, using silicon germanium in place of silicon for a channel region would have been obvious to one of ordinary skill in the art as such materials are art equivalent substrate/channel materials, as disclosed in more detail in Savant’s non-provisional application (Savant, Fig. 1A and ¶[0044]), as well as other prior art, including to Chen (Fig. 1B and ¶[0016]). Specifically, Chen, similarly to Savant’s non-provisional application, discloses that Si and SiGe are art recognized equivalent substrate/fin materials that can be used in order to meet specific design requirements for a semiconductor device.
Accordingly, since the prior art teaches all of the claimed elements, using such elements would lead to predictable results and as such it would have been obvious to one of ordinary skill in the art before the effective filing date of the claim invention to substitute SiGe for Si when forming a structure disclosed by combined teaching of Savant, Hsueh, Wang, Takahashi, Arimura, Horii, Yang, and Bilodeau or further in combination with Arita, in order to form a structure with desired characteristics.
Regarding claim 19 (18), the combined teaching of Savant, Hsueh, Wang, Takahashi, Arimura, Horii, Yang, Bilodeau and Chen, or further in combination with Arita, discloses the high dielectric constant material (Savant, 82, Fig. 1A) overlying the channel region (Savant, Fig. 1A).
Claim(s) 7-9 and 21 is/are rejected under 35 U.S.C. 103 as being unpatentable over Savant et al. (US 2020/0135915, hereinafter “Savant”, previously cited) in view of and Lei et al. (US 2019/0085451, hereinafter “Lei”, previously cited), Li et al. (US 2014/0127405, hereinafter “Li `405”), Takahashi et al. (US 2020/0063258, hereinafter “Takahashi”), Wang (US 9,142,764, hereinafter “Wang”, previously cited), Li et al. (US 2007/0116873, hereinafter “Li `873’, previously cited), Arita et al. (US 2011/0002155, hereinafter “Arita”), and Bilodeau et al. (US 2018/0337253, hereinafter “Bilodeau”), with Smith et al. (US 9,911,595, hereinafter “Smith”, previously cited) relied upon for showing that ALD is a self-limiting process.
Regarding claim 7, Savant teaches in Figs. 1A-1B (Fig. 1A shown above) and related text a method of forming a structure including a silicon nitride layer, the method comprising the steps of:
providing a substrate (10, Fig. 1A and ¶[0044]) comprising a material selected from the group consisting of silicon, silicon oxide, germanium, germanium oxide, germanium tin, silicon germanium, silicon germanium tin, and silicon carbide (¶[0044] and Embodiment 1, Fig. 2 of the provisional application), in a reaction chamber (¶[0063]);
depositing a first layer comprising titanium nitride (83, Fig. 1A and ¶¶[0026] and [0063]-[0064]) overlying and in contact with the substrate; and
depositing a second layer consisting of silicon nitride (84, Fig. 1A and ¶¶[0027] and [0064]-[0065]) overlying and in contact with the first layer,
wherein the second layer (silicon nitride) has a formula of SiNx where x is about 1.2 to about 1.4 (¶[0031] and [0021] of the provisional application, e.g. x=1.22, which falls between about 1.2 and about 1.4, in SiNx when x=0.45, y=0 and z=0.55 in SixTiyNz disclosed by Savant). Alternatively, assuming that Savant does not explicitly teach SiNx layer where x is about 1.2 to about 1.4, forming silicon nitride layer with the different ratio of nitrogen would have been within the capabilities of one of ordinary skill in the art as it would amount to nothing than changing flow ratio of nitrogen gas in order to produce silicon nitride layer that meets specific design requirements as evidenced by Arita (Fig. 3 and ¶[0104]).
Accordingly, since the prior art teaches all of the claimed elements using such elements would lead to predictable results, and as such, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention, absent of any unexpected results or criticality thereof, to form the silicon nitride layer disclosed by Savant with the a formula of SiNx where x is about 1.2 to about 1.4 as doing so would amount to nothing more than changing flow ratio of nitrogen gas in order to produce silicon nitride layer that meets specific design requirements.
Savant, however, does not explicitly teach that the second layer is exposed to a hydrogen plasma treatment in-situ. Savant, also does not explicitly teach that the substrate further comprises a metal carbide layer directly disposed on the material of the substrate and, as a result, that the titanium nitride layer overlies and is in contact with the metal carbide layer. Moreover, Savant does not explicitly teach in the provisional application that the step of depositing the first layer and the step of depositing the second layer are performed within the same reaction chamber and that the steps of depositing the first layer and the step of depositing the second layer each include introducing a nitrogen reactant into the reaction chamber, the nitrogen reactant being the same for the step of depositing the first layer and for the step of depositing the second layer and wherein the step of depositing the first layer further comprises forming a plasma to generate excited nitrogen-containing species from the nitrogen reactant. Lastly, Savant does not explicitly teach forming a laminate structure by repeating the steps of depositing the first layer and depositing the second layer and that the second layer consists of silicon nitride and impurities of carbon, hydrogen, and chlorine.
To begin with Lei, in a similar field of endeavor, teaches performing hydrogen plasma treatment after the step of depositing a silicon nitride layer (second layer) in order to affect one or more properties of the silicon nitride layer so that they meet specific design requirement (¶[0109]).
Thus, since the prior art discloses all of the method steps, using such steps would lead to predictable result, and, as such, one of ordinary skill in the art would have found it obvious, before the effective filing date of the claimed invention, to perform hydrogen treatment after the step of depositing a second layer (silicon nitride layer) as disclosed by Lei in the method disclosed by Savant, or further Arita in order to affect one or more properties of the second layer (silicon nitride layer) so that they meet specific design requirement. It is noted that the hydrogen plasma treatment disclosed by Savant is performed in-situ in a similar manner that applicant’s hydrogen plasma treatment is performed in-situ. Specifically, similar to the applicant, Lei teaches that hydrogen plasma treatment of the silicon nitride layer is performed after the silicon nitride layer is deposited using a plasma apparatus.
Moreover, Li `405, in a similar field of endeavor, teaches providing a substrate (200, 260, Fig. 3, ¶¶[110] and [0017]) comprising a material selected from the group consisting of silicon, silicon oxide, germanium, germanium oxide, germanium tin, silicon germanium, silicon germanium tin, and silicon carbide (¶¶[0110] and [0117]), and further comprising a metal carbide layer (220, Fig. 3, ¶¶[0117]-[0138]) directly disposed on the material of the substrate, when forming a structure similar to that disclosed by Savant and Lei, in order to set the work function of the gate.
Thus, since the prior art discloses all of the claimed elements, using such elements would lead to predictable results, and as such it would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the invention pertains to provide a substrate comprising a material such as silicon oxide, with a metal carbide layer directly disposed on the material of the substrate, as disclosed by Li `405, in the method disclosed by Savant and Lei, and/or further Arita in in order to set the work function of the gate.
Additionally, Savant teaches in the non-provisional application that the steps of depositing first and second layers (titanium nitride and silicon nitride layers) can be performed within the same reaction chamber (¶[0064]), which is consistent with the teaching of Takahashi and Wang, who both disclose that first and second layers (titanium nitride and the silicon nitride layers) disclosed by Savant can be formed within the same reaction chamber (Takahashi, Fig. 2 and ¶¶[0034]-[0051] and Wang, col. 6, ll. 13-56, col. 11. 52-63 and col. 12, ll. 28-65) in order to prevent wafer contamination and/or oxidation of previously formed layers, reduce processing cost and increase processing speed (Wang, col 6, ll. 23-30 and Savant, ¶¶[0034]-[0035]). Furthermore, Takahashi and Wang also teach that the steps of depositing the first layer (titanium nitride) and the step of depositing the second layer (silicon nitride) each include introducing a nitrogen reactant into the reaction chamber, the nitrogen reactant being the same for the step of depositing the first layer (titanium nitride) and for the step of depositing the second layer (silicon nitride) (e.g. NH3, Takahashi, Fig. 2 and ¶¶[0017], [0021], [0026] and [0042] and Wang, col. 14, ll. 6-21, col. 15, ll. 23-44 and col. 16, ll. 15-18) in order to simplify the manufacturing process.
Thus, since the prior art teaches all of the claimed method steps, executing such steps would lead to predictable results, and as such, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to perform the steps of depositing the first layers (titanium nitride) and second layer (silicon nitride) within the same reaction chamber, with each of the disposition steps including the same nitrogen reactant, as disclosed by Takahashi and Wang, in the method disclosed by Savant Lei, and Li `405 and/or further Arita, in order to prevent wafer contamination and/or oxidation of previously formed layers, simplify manufacturing process, reduce processing cost and increase processing speed.
Moreover, Li `873, in a similar field of endeavor, teaches that depositing titanium nitride layer by atomic layer deposition (ALD), as disclosed by Savant, Li, Takahashi and Wang or further in combination with Arita, and plasma-enhanced ALD (PE-ALD) as claimed, which involves forming plasma to generated excited nitrogen-containing species from the nitrogen reactant are art recognized equivalent processes (¶¶[0007] and [0047]) that can be used in order to form films with improved uniformity in layer thicknesses (¶[0007). Therefore, because these two processes were art-recognized equivalents before the effective filing date of the claimed invention, one of ordinary skill in the art would have found it obvious to deposit the first layer (titanium nitride layer) by using a PE-ALD which involves forming a plasma to generate exited nitrogen-containing species from the nitrogen reactant, for ALD.
In addition, repeating the steps of depositing the first layer (titanium nitride) and depositing the second layer (silicon nitride) in order to form a laminate structure would be obvious to one of ordinary skill in the art in order to form a structure with desired properties and would amount to nothing more than repeating known steps.
Thus, it would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the invention pertains to repeat the steps of depositing the first layer (titanium nitride) and depositing the second layer (silicon nitride layer) in order to form a structure with desired properties that meets specific design requirements.
Lastly, Bilodeau, in a similar field of endeavor, teaches that a layer of silicon nitride (second layer) is known in the art as corresponding to a pure silicon nitride, as well, as impure silicon nitride that includes hydrogen, carbon and/or oxygen impurities in the crystal structure (¶[0025]) depending on the precursors or the process used to form the silicon nitride layer.
Accordingly, it would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the invention pertains to have impurities of carbon, hydrogen, and chlorine in the silicon nitride layer disclosed by the combined teaching of Savant, Lei, Li `405, Takahashi and Wang, and Li `873, or further in combination with Arita, as such layer is known in the art as including both the pure and impure silicon forms depending on the precursors or process used to form the silicon nitride layer.
Regarding claim 8 (7), the combined teaching of Savant, Lei, Li `405, Takahashi, Wang, Li `873, and Bilodeau, or further in combination with Arita discloses wherein the metal carbide layer consists titanium aluminum carbide (Li `405, ¶¶[0042], [0045] and [0117]-[0138]).
Regarding claim 9 (7), the combined teaching of Savant, Lei, Li `405, Takahashi, Wang, Li `873, and Bilodeau, or further in combination with Arita discloses wherein the laminate structure comprises a bottom layer of titanium nitride and a top layer of silicon nitride, wherein the top layer prevents or mitigates oxidation of titanium nitride in the laminate structure (i.e. as discussed in the rejection of claim 7, Savant teaches forming a bottom layer of titanium nitride and a top layer of silicon nitride, where repeating the steps of forming titanium nitride and silicon nitride layers to form a laminate with the bottom layer of titanium nitride and top layer of silicon nitride would have been within the capabilities of one of ordinary skill in the art, as it would amount to nothing other than using known steps in order to form a desired laminate structure. It is noted that when the silicon nitride layer is formed as a top layer it would prevent or mitigate oxidation of titanium nitride in the laminate structure).
Regarding claim 21 (7), the combined teaching of Savant, Lei, Li `405, Takahashi, Wang, Li `873, and Bilodeau or further in combination with Arita, discloses wherein the step of depositing the second layer comprises exposing the substrate to a silicon halide precursor or a chlorosilane precursor (Savant, ¶[0065], Takahashi, ¶[0024] and Wang, col. 15, ll. 6-22) and the nitrogen reactant (Savant, ¶[0065], Takahashi, ¶[0026] and Wang, col. 16, ll. 15-18) and wherein the step of depositing the second layer is self-limiting (Takahashi, ¶[0030], where it is noted that the ALD technique used to deposit silicon nitride layer disclosed by Savant, Takahashi and Wang is a self-limiting by definition as evidenced by Smith, col. 4, ll. 8-19) at a thickness of 1Å to 300Å (Savant, ¶[0035]) which is overlapping the claimed range of 0.5 to 2 Angstroms, where it would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to adjust the range of Savant to include the claimed range as a routine skill in the art to discover the optimum and/or workable range. See MPEP § 2144.05 for overlap of ranges.
Claim(s) 1, 5, and 16-17 is/are rejected under 35 U.S.C. 103 as being unpatentable over Hsueh (US 2014/0103284, hereinafter “Hsueh”, previously cited) in view of Rocklein et al. (US 2019/0267383, hereinafter “Rocklein”, previously cited), Wang et al. (US 2016/0149130, hereinafter “Wang `130”, previously cited), Arita (US 2011/002155, hereinafter “Arita, previously cited) and Yasuda et al. (US 2014/0191182, hereinafter “Yasuda”) or over Hsueh in view of Wang (US 9,142,764, hereinafter “Wang”, previously cited), Takahashi (US 2020/0063258, hereinafter “Takahashi”, previously cited), Wang et al. (US 2016/0149130, hereinafter “Wang `130”, previously cited), Arita (US 2011/002155, hereinafter “Arita, previously cited), and Yasuda et al. (US 2014/0191182, hereinafter “Yasuda”) and Bilodeau et al. (US 2018/0337253, hereinafter “Bilodeau”), with Smith et al. (US 9,911,595, hereinafter “Smith”, previously cited) relied upon for showing that ALD is a self-limiting process.
Regarding claim 1, Hsueh teaches in Figs. 3-5 (Figs. 3-4 shown below) and related text a method of forming a structure including a silicon nitride layer, the method comprising the steps of:
providing a substrate (302, 304, Fig. 3 and ¶[0048] and step 402, Fig. 4 and ¶[0067]) comprising a surface (Fig. 3), wherein the surface comprises a material comprising one or more of silicon, germanium, germanium oxide, germanium tin, silicon germanium, silicon germanium tin, silicon carbide, or a group III-V semiconductor material (¶¶[0049]-[0050]), and further comprising a high dielectric constant material (308, Fig. 3 and ¶¶[0009], [0048], [0051] and step 405, Fig. 4, ¶¶[0048] and [0051]) overlying and in contact with a passivation layer (305, Fig. 3 and ¶[0050]) disposed on the surface (304, Fig. 3), in a reaction chamber (502, Fig. 5 and ¶¶0080]-[0081]), wherein the high dielectric constant (308, Fig. 3 and ¶¶[0009], [0048], [0051] and step 405, Fig. 4, ¶¶[0048] and [0051]);
with the reaction chamber at a temperature (¶[0076]), depositing a first layer comprising titanium nitride (312, Fig. 3 and ¶¶[0071]-[0073] and step 406, Fig. 4 and ¶¶[0072]-[0073] and [0077]) overlying and in contact with the high dielectric constant material (308, Fig. 3) in the reaction chamber (502, Fig. 5 and ¶¶[0071]-[0073] and [0080]-[0081]); and
with the reaction chamber at about the temperature (¶[0076]), depositing a second layer consisting silicon nitride (314, Fig. 3 and ¶¶[0071]-[0073] and step 406, Fig. 4 and ¶¶[0072]-[0073] and [0077]) overlying and in contact with the first layer (312, Fig. 3) in the reaction chamber (502, Fig. 5 and ¶¶[0071]-[0073] and [0080]-[0081]),
wherein the step of depositing the second layer is self-limiting at a thickness less than about 2 Angstroms (i.e. between 0.25 Angstroms and about 2 Angstroms, ¶[0073], where it is noted that the ALD technique used to deposit silicon nitride layer disclosed by Hsueh is a self-limiting (¶[0075]) as evidenced by Smith, col. 4, ll. 8-19), and
wherein the step of depositing the first layer and the step of depositing the second layer are performed within the reaction chamber (502, Fig. 5 and ¶¶[0071]-[0077] and [0080]-[0081]).
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Hsueh, however, does not explicitly teach that the passivation layer comprises a silicon oxide cap disposed on the silicon layer or that high dielectric constant material comprises one or mor of lanthanum silicate and aluminum silicate. Hsueh also does not explicitly teach that the second layer consisting of silicon nitride has a formula of SiNx where x is about 1.2 to about 1.4 or that the second layer consists of silicon nitride and impurities of carbon, hydrogen, and chlorine. Moreover, assuming under a different interpretation from that above, that Hsueh fails to teach that the metal nitride layer overlying and in contact with the high dielectric constant is titanium nitride and that the reaction chamber during the step of depositing the layer comprising silicon nitride is at about the temperature used during the step of depositing the metal nitride layer, it is noted that Wang, in a similar field of endeavor, teaches that tantalum nitride disclosed by Hsueh and titanium nitride are well-known equivalents that can be used when forming the structure (i.e. an embedded resistors of ReRAM cell) disclosed by Hsueh (Wang, col. 6, ll. 19-20 and col. 15, ll. 23-44) and Takahashi teaches that both titanium nitride layer and silicon nitride layer, such as those disclosed by Hsueh and Wang, can be formed in the same reaction chamber at the same reaction chamber temperature (Takahashi, ¶¶[0053] and [0071]).
Thus, since the prior art teaches all of the claim elements using such elements would lead to predictable results, and as such it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to substitute titanium nitride for tantalum nitride in the method for forming a structure including silicon nitride layer disclosed by Hsueh, as the two materials were art-recognized equivalents. Moreover, it would it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to form the layer of silicon nitride in the method disclosed by Hsueh at about the same temperature as that used during the step of depositing the titanium nitride layer as doing so would amount to nothing more than using known processing conditions to form the same structure as claimed. Additionally, it is noted that forming titanium nitride and silicon nitride layer within the same reaction chamber at the same chamber temperature, absent of any showing of unexpected results or criticality would have been obvious to one of ordinary skill in the art as it would amount to nothing more than selecting an optimum temperature by routine experimentation from the temperature range disclosed by Hsueh, Wang and Takahashi.
Furthermore, while Hsueh and Takahashi, or in the alternative Hsueh, Wang, and Takahashi do not explicitly teach that the titanium nitride layer further comprises a dopant selected from the group consisting of aluminum, tantalum, lanthanum, hafnium, and tungsten including a dopant in a titanium nitride layer would have been within the capabilities of one of ordinary skill in the art as evidenced by Rocklein. Specifically, Rocklein, in a similar field of endeavor teaches that titanium nitride metal films that are used in memory devices similar to those disclosed by Hsueh can be doped with aluminum, hafnium, tungsten in order to achieve a desired resistivity or work function properties for the metal (¶[0036]).
Thus, since the prior art discloses all of the claimed elements, the results would be predictable to one of ordinary skill in the art, and as such it would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the invention pertains to dope the titanium nitride layer disclosed by the combined teaching of Hsueh and Takahashi, or in the alternative, Hsueh, Wang, and Takahashi, with one of aluminum, tungsten, or hafnium as disclosed by Rocklein in order to obtain TiN film with desired characteristics.
In addition, Wang `130 in a similar field of endeavor teaches that the resistive switching layer, such as that disclosed by Hsueh, Takahashi, and Rocklein, or in the alternative, Hsueh, Wang, Takahashi and Rocklein, formed on a silicon layer, can additionally include a silicon oxide layer on which the high dielectric constant material layer of the resistive switching layer is formed in order to control resistance of the resistive switching layer to meet specific design requirements (¶[0037]).
Thus, since the prior art discloses all of the claimed elements, the results would be predictable to one of ordinary skill in the art, and as such it would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the invention pertains to include a silicon oxide layer as disclosed by Wang `130 on the silicon layer disclosed by Hsueh, Takahashi, and Rocklein, or in the alternative Hsueh, Wang, Takahashi and Rocklein, in order to control resistance of the resistive switching layer to meet specific design requirements.
Moreover, Arita, in a similar field of endeavor, teaches that a silicon nitride layer, such as that disclosed by Hsueh, Rocklein, and Wang `130 or in the alternative the combined teaching of Hsueh, Wang, Takahashi, Rocklein, and Wang `130, can be formed to have different compositions by varying flow ratio of a nitrogen gas in order to meet specific design requirements. Specifically, Arita teaches in Fig. 3 and related text that composition of the silicon nitride layer (SiNx) can include SiNx with x value between 1.2 to about 1.4 by varying the flow ratio of nitrogen gas (Fig. 3 and ¶[0104]) in order to form silicon nitride layer with desired composition.
Accordingly, since the prior art teaches all elements of the claim, using such elements would lead to predictable results, and as such it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invitation, absent of any unexpected results or criticality thereof, to form the silicon nitride layer disclosed by Hsueh, Rocklein, and Wang `130 or in the alternative the combined teaching of Hsueh, Wang, Takahashi, Rocklein, and Wang `130 to have a composition of SiNx layer with x between 1.2 to about 1.4, as doing so would amount to nothing other than varying the flow ratio of nitrogen gas in order to produce silicon nitride layer that meets specific design requirements.
Additionally, Yasuda, in a similar field of endeavor teaches that HfO, TaO, AlO, YO, ZrO, disclosed by Hsueh as high dielectric constant resistive switching materials and aluminum silicate (i.e. SiAlO), as claimed, are art recognized equivalent materials (¶¶[0019]-[0021]). Therefore, because these high dielectric constant resistive switching materials were art-recognized equivalents before the effective filing date of the claimed invention, one of ordinary skill in the art would have found it obvious to substitute aluminum silicate for HfO, TaO, AlO, YO, ZrO, disclosed by Hsueh, Rocklein, and Wang `130 or in the alternative Hsueh, Wang, Takahashi, Rocklein, and Wang `130.
Lastly, Bilodeau, in a similar field of endeavor, teaches that a layer of silicon nitride (second layer) is known in the art as corresponding to a pure silicon nitride, as well, as impure silicon nitride that includes hydrogen, carbon and/or oxygen impurities in the crystal structure (¶[0025]) depending on the precursors or the process used to form the silicon nitride layer.
Accordingly, it would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the invention pertains to have impurities of carbon, hydrogen, and chlorine in the silicon nitride layer disclosed by the combined teaching of Hsueh, Rocklein, and Wang `130 or in the alternative Hsueh, Wang, Takahashi, Rocklein, and Wang `130, as such layer is known in the art as including both the pure and impure silicon forms depending on the precursors or process used to form the silicon nitride layer.
Regarding claim 5 (1), the combined teaching of Hsueh, Takahashi, Rocklein, Wang `130, Arita, Yasuda, and Bilodeau, or in the alternative, the combined teaching of Hsueh, Wang, Takahashi, Rocklein, Wang `130, Arita, Yasuda, and Bilodeau was discussed above in the rejection of claim 1 and includes a discussion of the temperature in the reaction chamber during the step of depositing the layers comprising titanium nitride and silicon nitride being between 200°C and about 350°C (Hsueh, ¶[0076]) or 350°C and about 450°C (Takahashi, ¶[0053]), which is overlapping the claimed range of between about 450°C and about 600°C.
Therefore, it would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to adjust the range of Hsueh to include the claimed range as a routine skill in the art to discover the optimum and/or workable range. See MPEP § 2144.05 for overlap of ranges.
Regarding claim 16 (1), the combined teaching of Hsueh, Takahashi, Rocklein, Wang `130, Arita, Yasuda, and Bilodeau or in the alternative, the combined teaching of Hsueh, Wang, Takahashi, Rocklein, Wang `130, Arita, Yasuda, and Bilodeau further discloses forming a laminate structure by repeating the steps of depositing the first layer (titanium nitride) and depositing the second layer (silicon nitride with impurities of carbon, hydrogen, and chlorine), wherein the laminate structure is capped with a layer comprising silicon nitride (Hsueh, Fig. 3 and ¶[0072], Wang, col. 13 and ll. 43-54 and Takahashi, ¶¶[0072]-[0073]).
Regarding claim 17 (1), the combined teaching of Hsueh, Takahashi, Rocklein, Wang `130, Arita, Yasuda, and Bilodeau or in the alternative the combined teaching of Hsueh, Wang, Takahashi, Rocklein, Wang `130, Arita, Yasuda, and Bilodeau further discloses a structure formed according to the method of claim 1 (Hsueh, Fig. 3). Moreover, it is noted that the claim is product-by-process claim, and therefore is treated according to MPEP § 2113, which states that “even though product-by-process claims are limited by and defined by the process, determination of patentability is based on the product itself.” The patentability of a product does not depend on its method of production. Since Hsueh, Rocklein, Wang `130, Arita, Yasuda, and Bilodeau or in the alternative the combined teaching of Hsueh, Wang, Takahashi, Rocklein, Wang `130, Arita, Yasuda, and Bilodeau disclose all the structure, the claimed method does not distinguish it from the prior art.
Claim(s) 20 is/are rejected under 35 U.S.C. 103 as being unpatentable over Savant et al. (US 2020/0135915, hereinafter “Savant”, previously cited) in view of Tang et al. (US 2017/0117202, hereinafter “Tang `202”, previously cited), Woodruff et al. (US 2018/0323055, hereinafter “Woodruff,” previously cited), Takahashi et al. (US 2020/0063258, hereinafter “Takahashi”, previously cited), Wang (US 9,142,764, hereinafter “Wang”, previously cited), Li et al. (US 2007/0116873, hereinafter “Li `873’, previously cited), Joo et al. (US 2008/0157185, hereinafter “Joo”), Arimura (US 2017/0162686, hereinafter “Arimura”, previously cited) and/or Hsueh et al. (US 2014/0103284, hereinafter “Hsueh”, previously cited).
Regarding claim 20, Savant teaches in Figs. 1A and 1B (shown above) and related text a method of forming a structure including a silicon nitride layer, the method comprising the steps of:
providing a substrate (10, Fig. 1A and ¶[0044]) comprising silicon or silicon dioxide (¶[0044] and Embodiment 1, Fig. 2 of the provisional application) and further comprising an interface layer (81, Fig. 1A and ¶[0063]) comprising a layer of silicon or silicon dioxide with a thickness less than about 1 nm (¶[0063], where Savant teaches that the range for the interfacial layer is from about 0.2 nm to about 6 nm which overlaps the claimed range of less than about 1 nm where it would have been obvious to one of ordinary skill in the art to adjust the range of Savant to include the claimed range as a routine skill in the art to discover the optimum and/or workable range. See MPEP § 2144.05 for overlap of ranges.) and a high dielectric constant material layer (82, Fig. 1A and ¶[0063]) in a reaction chamber (¶[0063]);
depositing a first layer comprising titanium nitride (83, Fig. 1A and ¶¶[0026] and [0063]-[0064]) overlying and in contact with the high dielectric constant material layer; and
depositing a second layer consisting of silicon nitride (84, Fig. 1A and ¶¶[0027] and [0064]-[0065]) overlying and in contact with the first layer.
Savant, however, does not explicitly teach that the substrate comprises a passivation layer comprising a H2S or hydrazine pretreated interface disposed directly above the silicon or silicon dioxide of the substrate and that the first layer and the second layer are formed using a cyclic deposition processes (i.e. that the ALD process disclosed by Savant is cyclic deposition process), with the first layer deposited by exposing the substrate to a titanium precursor and a nitrogen reactant, wherein the nitrogen reactant is exposed to a plasma to generate excited nitrogen-containing species and wherein the step of forming the first layer and the step of forming the second layer are performed within the reaction chamber with the reaction chamber at the same pressure without an intervening vacuum break. Savant also does not explicitly teach that depositing of the second layer comprises providing Si3H8 to the reaction chamber. Lastly, Savant does not explicitly teach forming a laminate structure by repeating the steps of depositing the first layer and depositing the second layer wherein the laminate structure comprises a bottom layer of titanium nitride and a top layer of silicon nitride, wherein the top layer prevents or mitigates oxidation of titanium nitride in the laminate structure.
To begin with, Tang `202, in a similar field of endeavor, teaches providing a substrate with a passivation layer comprising a H2S (¶¶[0029]-[0030]) interface disposed directly above silicon (i.e. since the surface of the substrate is treated the passivation layer would be directly above the surface of the substrate) prior to depositing a dielectric material when forming a structure such as that disclosed by Savant in order to reduce interface trap density between the substrate and the dielectric layer material (¶¶[0005]-[0007]).
Thus, since the prior art discloses all of the claimed elements, using such elements would lead to predictable results, and as such it would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the invention pertains to provide a substrate comprising a passivation layer as disclosed by Tang `202 in the method disclosed by Savant in order to reduce interface trap density between the substrate and the dielectric layer material thereby increasing performance of the finally formed device.
Moreover, Woodruff, in a similar field of endeavor, teaches that ALD process disclosed by Savant (¶¶[0064]-[0065] and [0071]) used in forming titanium nitride and silicon nitride layers is a process that involves cyclic deposition (i.e. “deposition cycles, preferably a plurality of consecutive deposition cycles,” ¶[0020]) and Takahashi and Wang both teach that the titanium nitride layer deposited using ALD can be formed by exposing the substrate to a titanium precursor and a nitrogen reactant (Takahashi, ¶¶[0019] and [0021] and Wang, col. 14, ll. 15-21 and col. 15, ll. 23-24) and that both the titanium nitride layers and the silicon nitride layers disclosed by Savant and Tang `202 can be formed within the same chamber with the reaction chamber at a predetermined pressure without an intervening breaking vacuum (Savant, ¶[0064], Takahashi, ¶[0053] and Wang, col. 6, ll. 13-56, col. 11. 52-63 and col. 12, ll. 28-65) in order to prevent wafer contamination and/or oxidation of previously formed layers, reduce processing cost and increase processing speed (Savant, ¶¶[0034]-[0035] and [0064] and Wang, col. 6, ll. 23-30).
Thus, it would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the invention pertains to use cyclic deposition process to form the layers comprising titanium nitride and silicon nitride as such deposition is well-known in the art as being part of the ALD process. Moreover, since the prior art teaches all of the claimed method steps, executing such steps would lead to predictable results, and as such, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to deposit both TiN and SiN in the reaction chamber with the reaction chamber at a predetermined pressure without an interviewing vacuum break based on the teaching of Savant, Tang `202, Woodroof, Takahashi and Wang as such steps are well-known in the art and would allow to prevent wafer contamination and/or oxidation of previously formed layer(s), decrease processing cost and increase processing speed. It is noted that forming titanium nitride and silicon nitride layer within the same reaction chamber at the same chamber pressure, absent of any showing of unexpected results or criticality would have been obvious to one of ordinary skill in the art as it would amount to nothing more than selecting an optimum pressure by routing experimentation from the pressure range disclosed by Savant, Tang `202, Woodruff, Takahashi and Wang.
Additionally, Li `873, in a similar field of endeavor, teaches that depositing titanium nitride layer (first layer) by atomic layer deposition (ALD), as disclosed by Savant, Tang `202, Woodruff, Takahashi and Wang and plasma-enhanced ALD (PE-ALD) as claimed, which involves forming plasma to generated excited nitrogen-containing species from the nitrogen reactant are art recognized equivalent processes (¶¶[0007] and [0047]) that can be used in order to form films with improved uniformity in layer thicknesses (¶[0007). Therefore, because these two processes were art-recognized equivalents before the effective filing date of the claimed invention, one of ordinary skill in the art would have found it obvious to deposit titanium nitride layer by using a PE-ALD which involves forming a plasma to generate exited nitrogen-containing species from the nitrogen reactant, for ALD.
Furthermore, using Si3H8 to form SiN layer (second layer) disclosed by Savant is well-known in the art as evidenced by Joo (¶[0028]). Accordingly, it would have been obvious to one of ordinary skill in the art before the before the effective filing date of the claimed invention to use Si3H8 disclosed by Joo to form SiN disclosed by Savant as doing so would amount to nothing other than using a known material based on its suitability for its intended purpose.
In addition, assuming Savant does not explicitly teach that the interface layer comprising a layer of silicon or silicon oxide has a thickness of less than about 1 nm, forming an interface layer of silicon or silicon oxide to the claimed thickness would nonetheless be obvious to one of ordinary skill in the art as evidenced by Arimura. Specifically, Arimura, in a similar field of endeavor, teaches a passivation layer (101, Fig. 1) may include a silicon layer (¶¶[0068]-[0069]) and a silicon oxide cap (i.e. interfacial layer 102, Fig. 1 and ¶¶[0068]-[0069]) formed between a substrate (100, Fig. 1 and ¶¶[0068]-[0069]) and a high dielectric constant material (104, Fig. 1 and ¶¶[0068]-[0069]) and TiN layer (105, Fig. 1 and ¶¶[0068]-[0069]) wherein the thin layer of silicon has a thickness of 1 angstrom (0.1 nm) to about 10 angstrom (1 nm) or less in order to increase electron mobility in the device (¶[0075]).
Accordingly, since the prior art teaches all of the claimed elements, using such elements would lead to predictable results and as such it would have been obvious to one of ordinary skill in the art before the effective filing date of the claim invention to form the thin layer of silicon as an interface layer disclosed by Savant, Tang `202, Woodruff, Takahashi and Wang to the claimed thickness as disclosed by Arimura in order to in order to increase electron mobility in the device.
In addition, repeating the steps of depositing the first layer (titanium nitride) and depositing the second layer (silicon nitride) in order to form a laminate structure would be obvious to one of ordinary skill in the art in order to form a structure with desired properties and would amount to nothing more than repeating known steps.
Thus, it would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the invention pertains to repeat the steps of depositing the first layer (titanium nitride) and depositing the second layer (silicon nitride layer), wherein the laminate structure comprises a bottom layer of titanium nitride and a top layer of silicon nitride in order to form a structure with desired properties that meets specific design requirements. It is noted that when the silicon nitride layer is formed as a top layer in the laminate structure, it would prevent or mitigate oxidation of titanium nitride in the laminate structure.
Response to Arguments
Applicant's arguments filed May 5, 2026 have been fully considered but they are either not persuasive or moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument .
To begin with, on page 8, the Applicant argues that in “the shield film …“SixTiyNz, where 0≤x<1, 0≤y<1, 0≤x<1, and x+y+z=1, “[a] person with ordinary skill in the art would recognize that “≤” is a typographical error and was intended to mean “<.” A person with ordinary skill in the art would recognize that allowing certain combination of x, y, and z to be 0 or 1 would give nonsensical results, such as Si0Ti0N1, which would be a layer of pure nitrogen”. While it might be true that some of result may be nonsensical, others, such having shield layer made of SiN (where y=0, as explicitly taught be Savant in [0027]) would nonetheless result in valid material for the shield layer. Accordingly, contrary to the Applicant’s argument, one of ordinary skill in the art would not consider the formula SixTiyNz, where 0≤x<1, 0≤y<1, 0≤x<1, and x+y+z=1 disclosed by Savant as having a typographical error.
Moreover, with respect to the Applicant’s argument that the SiN disclosed by Savant includes fluorine, it is noted that Savant teaches that the disclosed shield layer may include fluorine in some of the embodiments and not all. Accordingly, presence of fluorine in some of the embodiments does not prevent its absence or presence of other impurities in other embodiments.
Furthermore, on pages 8-9 and 12-13 the Applicant argues that “Hsueh does not teach the formation of SiN over a TiN layer. Hsueh teaches layer of silicon nitride over tantalum nitride, not titanium nitride. While Hsueh [0071]-[0073] mentions “titanium,” a person with ordinary skill in the art would recognize that this a typographical error and understand the intended meaning was “tantalum”. Moreover, the Applicant argues that there is no motivation to replace bilayer of TiN and SiN with a laminate structure”.
To begin with, as discussed above, even assuming that Hsueh does not explicitly teach using titanium nitride, Wang, in a similar field of endeavor, teaches that tantalum nitride disclosed by Hsueh and titanium nitride, as claimed, are well-known equivalents that can be used when forming the structure (i.e. an embedded resistors of ReRAM cell) disclosed by Hsueh. Moreover, as discussed above, repeating known steps to form known layers on top of one another would have been within capabilities of one of ordinary skill in the art in order to form a structure with desired properties. Accordingly, contrary to the Applicant’s argument, the prior teaches all elements of the claim.
Relevant Prior Art
The following prior art is relevant to the invention but not relied upon in any of the rejections:
Kim et al. (Atomic Layer Deposition of Silicon Nitride Thin Films: A Review of Recent Progress, Challenges, and Outlooks, Materials, 2016, 9, 1007, pp. 1-20) teaches that silicon nitride layers are known to include impurities of carbon, hydrogen, and chlorine depending on the precursors and process used to form such materials.
Kim et al. (Silicon Nitride Atomic Layer Deposition: A Brief Review of Precursor Chemistry, Material Matters, 2018, 13.2) discusses various precursors and impurities within SiN films.
Niskanen et al. (US 2014/0273528) teaches that SiN includes impurities (¶[0025]).
Suemori et al. (US 10,559,458) teaches that SiN includes impurities (col. 2, ll. 1-6).
Conclusion
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/A.B.C/Examiner, Art Unit 2893
/SUE A PURVIS/Supervisory Patent Examiner, Art Unit 2893
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