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 .
Claim Rejections - 35 USC § 103
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.
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1, 4, 7, and 22-23 are rejected under 35 U.S.C. 103 as being unpatentable over Wang (US 20190385902 A1) in view of Tanaka (US 2004/0238486).
Regarding Claims 1 and 4, Wang teaches a method comprising forming a tri-layer structure over a substrate comprising a bottom, middle, and photosensitive layer formed over a finFET film stack as the semiconductor substrate (Fig. 1, paragraph [0013]-0018]). The photosensitive layer is patterned (Fig. paragraph [0019]) and a surface treatment is performed on the patterned photosensitive layer to form a non-conformal protection layer over the patterned photoresist layer to protect the mask during descum process (Fig. 2, paragraph [0053]). The middle layer and bottom layers are patterned after performing the surface treatment using an etching process, whereby the upper layer may be consumed (Fig. 7 and Fig. 8, paragraph [0054-0055]) and the substrate is etched (Fig. 13, paragraph [0058]). The patterned mask with the protective film is used as an etching mask for patterning the underlayers (paragraph [0064]) and to further preserve the critical dimensions and reduce the width of a trench between the etch masks (paragraph [0062]).
Wang is silent to performing a baking process with the surface treatment and rising with water to remove unreacted portion of the photosensitive layer.
However, Tanaka teaches a method to improve etching resistance of an etching mask by forming a protection layer containing a crosslinking agent that is insoluble in a developer containing water (abstract). The etching protection layer is formed at the interface of the resist pattern by applying a heating step to diffuse acid from the resist pattern to activate a crosslinking agent in the protection layer, hardening the layer over the resist pattern (paragraph [0024]). The protected resist pattern is then developed with water to remove the uncrosslinked protection layer (paragraph [0034]). One example of a crosslinker composition include the solvents 2-propanol and water and the crosslinker methoxymethylated melamine, which is contains 6 alkoxy (-OCH3) substituents (paragraph [0048]). However, the melamine group is not an alkyl group as instantly claimed. Tanaka further discloses embodiments of the crosslinking agent for forming an etching protection layer may comprise low molecular weight urea derivatives such as methoxymethylurea, dimethylolurea, ethylene urea, ethoxymethyl urea resins, and others and that these crosslinking agents may be used singly or in a mixture or two or more kinds (paragraph [0020]). Examiner notes that dimethylolurea satisfies the structure R—(NHRa)n where R is acetyl group, Ra is alkoxymethyl group, and n is 2 (Claims 1 and 4). The crosslinkable compositions improve etching resistance of a resist mask such that a good pattern can be transferred to the substrate in a short time (paragraph [0056]).
The non-conformal layer of Wang serves the same purpose as the crosslinkable protection layer of Tanaka. Each layer provides etching resistance during etching of underlayers. It would have been obvious for one of ordinary skill in the art to have substituted the non-conformal layer of Wang with the crosslinkable layer of Tanaka through routine experimentation with the reasonable expectation of forming a etch-resistant protection layer.
Regarding the crosslinkable composition being organic and alkyl, Tanaka discloses amine-containing crosslinkers that are both aromatic and alkyl as equivalents for one another, such as the melamine resins and the urea resins. It would have been obvious for one of ordinary skill in the art to have substituted the melamine resins with the alkylurea resins through routine experimentation. One of ordinary skill would reasonably expect this modification to result in a crosslinkable protection layer having similar properties.
Regarding Claim 7, Wang further teaches the method of claim 1 wherein the patterned photosensitive layer is removed after patterning the bottom layer (Fig. 8, paragraph [0055] describes patterning the bottom layer in an etching process whereby the upper patterned layer may be consumed).
Regarding Claim 22, the discussion of Claim 1 is relied upon as above. Tanaka further discloses a composition for forming an etching protection layer is applied on the substrate having a resist pattern formed; as a coating method, there may be used any methods so far applied when a photoresist is coated such as spin-coat, spray coat, dip coat, roller coat, and etc (paragraph [0012]). Tanaka demonstrates that the protection layer may be applied by any conventional means.
The Examiner notes that the dip coating method would require the protection layer to be prepared as a bath such that the substrate with the patterned photoresist was dipped and soaked into the bath as to coat the photoresist pattern.
Regarding claim 23, Wang teaches that the bottom layer 112 may be a bottom anti-reflective coating [0018].
Claim 3 is rejected under 35 U.S.C. 103 as being unpatentable over Wang (US 2019/0385902 A1) in view of Tanaka (US 2004/0238486) as applied to Claim 1, further in view of Lee (US 2015/0118852).
Regarding Claim 3, the discussion of Claim 1 is relied upon as above. Tanaka discloses the protection layer crosslinks the surface of the patterned photoresist (paragraph [0024]).
Tanaka is silent to what happens to underlayers beneath the patterned photoresist layer.
However, in the same field of endeavor, Lee teaches capping composition formed on the upper and side surfaces of the photoresist pattern (abstract). The capping composition is cross-linked after a baking process using the residual acid in the photoresist layer and does not crosslink the middle layer (Fig. 6 and Fig. 7, paragraph [0060]). This capping layer formed on the photoresist pattern is used as an etch mask (paragraph [0022]) to prevent degradation of etch resistance (paragraph [0088]). Further, Lee discloses the substrate may include an etching target layer for the photoresist to be applied on (Fig. 8, the capping layer 145 prevents degradation of the resist pattern during etching of the target layer 110). It is deduced that the crosslinked coating formed on the patterned photoresist protects the pattern mask while etching underlayers such as the etching target layer.
Tanaka and Lee utilize similar crosslinkable compositions to attach a protection layer at the surface of the patterned photoresist. The compositions crosslink due to diffusion of residual acid from the surface of the patterned photoresist to the protection layer. The teaching of Tanaka and Lee demonstrate that the crosslinkable compositions would attach to any layers that generate acid to crosslink at the surface. It would have been obvious for one of ordinary skill in the art to have applied a protection coating to a resist layer that covers resist underlayers as discussed in Lee through routine experimentation. One of ordinary skill would understand from the teachings of Tanaka and Lee that underlayer which do not contain a generated acid will not crosslink the protection layer.
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Claim 5 is rejected under 35 U.S.C. 103 as being unpatentable over Wang (US 20190385902 A1) in view of Tanaka (US 2004/0238486) as applied to Claim 2, evidenced by Environmental Chemicals Desk Reference (Table 2.8. Octanol/Water Partition Coefficients of Organic Compounds. Retrieved from https://app.knovel.com/hotlink/itble/rcid:kpECDR0001/id:kt00CY5VS1/environmental-chemicals/table-2-8-octanol-water).
Regarding Claim 5, the discussion of Claim 2 is relied upon as above. Tanaka further discloses the protection layer comprises 2-propanol (paragraph [0034]).
Tanaka is silent to the partition ratio of 2-propanol.
However, Environmental Chemicals Desk Reference reports that the partition ratio of 2-propanol is 0.05 to 0.11. Therefore, the protection layer comprises an organic solvent having a partition ratio lower than 4.
Claims 8-11, 13, 15 and 21 are rejected under 35 U.S.C. 103 as being unpatentable over Wang (US 2019/0385902 A1) in view of Kanarik (US 2006/0089005 A1) and further in view of Tanaka (US 2004/0238486).
Regarding Claims 8 and 21, Wang teaches a method comprising forming a tri-layer structure over a substrate comprising a bottom, middle, and photosensitive layer formed over a finFET film stack as the semiconductor substrate (Fig. 1, paragraph [0013]-0018]). The photosensitive layer is patterned (Fig. paragraph [0019]) and developed using a developer (interpreted as the rinsing process as claimed) (paragraph [0020]) and a surface treatment is performed on the patterned photosensitive layer to form a non-conformal protection layer over the patterned photoresist layer to protect the mask during descum process (Fig. 2, paragraph [0053]). The middle layer and bottom layers are patterned after performing the surface treatment using an etching process, whereby the upper layer may be consumed (Fig. 7 and Fig. 8, paragraph [0054-0055]) and the substrate is etched (Fig. 13, paragraph [0058]). The patterned mask with the protective film is used as an etching mask for patterning the underlayers (paragraph [0064]) and to further preserve the critical dimensions and reduce the width of a trench between the etch masks (paragraph [0062]). Wang teaches that the middle layer 114 may be silicon nitride (a dielectric) and the photosensitive layer may be organic and therefore, a different material [0018].
Wang is silent to patterning the photosensitive layer then the middle layer and after patterning the middle layer, performing a surface treatment to form a protection layer cross-linking the sidewall of the patterned middle layer and the photosensitive layer.
Kanarik teaches forming a trilayer structure over a substrate consisting of a bottom etch layer 208, a middle BARC layer 210 and a patterned photoresist mask 212 (Fig. 2B). A conditioning process using conditioning plasma is performed to etch the BARC layer using the patterned photoresist as a mask (paragraph [0027-0030]. As a result, a protective layer 214 is formed over the top surface and sidewall of the patterned photoresist mask and the sidewall of the middle BARC layer (Fig 2B). After the conditioning process, the critical dimension of apertures in the photoresist mask has been reduced (paragraph [0027]). The bottom layer is subsequently patterned using the protective layer formed over the photoresist mask and the middle layer as an etch mask (Fig 2C, paragraph [0030]).
However, Kanarik does not teach the protection layer cross-linking the sidewall of the patterned middle layer and the patterned photosensitive layer and a top surface of the patterned photosensitive layer.
Examiner brings in Tanaka to teach a method to improve etching resistance of an etching mask by forming a protection layer containing a crosslinking agent that is insoluble in a developer containing water (abstract). The etching protection layer is formed at the interface of the resist pattern by applying a heating step to diffuse acid from the resist pattern to activate a crosslinking agent in the protection layer, hardening the layer over the resist pattern (paragraph [0024]). The protected resist pattern is then developed with water to remove the uncrosslinked protection layer (Claim 21) (paragraph [0034]). One example of a crosslinker composition include the solvents 2-propanol and water and the crosslinker methoxymethylated melamine, which is contains 6 alkoxy (-OCH3) substituents (paragraph [0048]). The crosslinkable compositions improve etching resistance of a resist mask such that a good pattern can be transferred to the substrate in a short time (paragraph [0056]). However, the melamine group is not an alkyl group as instantly claimed. Tanaka further discloses embodiments of the crosslinking agent for forming an etching protection layer may comprise low molecular weight urea derivatives such as methoxymethylurea, dimethylolurea, ethylene urea, ethoxymethyl urea resins, and others and that these crosslinking agents may be used singly or in a mixture or two or more kinds (paragraph [0020]).
The non-conformal film of Wang, the conditioning process of Kanarik, and the crosslinkable protection layer of Tanaka all serve the same purpose to protect the photoresist layer during etching processes to underlayers and to preserve the critical dimension after etching. It would have been obvious for one of ordinary skill in the art to have modified the non-conformal protecting film or Wang with the crosslinkable film as disclosed by Tanaka, and to protect the sidewalls of a middle layer as disclosed by Kanarik through routine experimentation. One of ordinary skill would reasonably expect the combination of teachings to produce a method that forms a crosslinkable layer over the patterned photoresist and a middle layer.
Regarding the crosslinkable composition being organic and alkyl, Tanaka discloses amine-containing crosslinkers that are both aromatic and alkyl as equivalents for one another, such as the melamine resins and the urea resins. It would have been obvious for one of ordinary skill in the art to have substituted the melamine resins with the alkylurea resins through routine experimentation. One of ordinary skill would reasonably expect this modification to result in a crosslinkable protection layer having similar properties regarding etch resistance.
Regarding etching the middle layer using an etchant gas, Wang suggests dry etch processes, possibly in combination with wet etch processes [0057-0058], Tanaka teaches etching gas [0037-0042], as does Kanarik [0034].
Regarding Claim 9, the discussion of Claim 8 is relied upon as above. Wang further teaches as part of etching the bottom layer, the upper layer, which comprises the protective layer, may be consumed (paragraph [0055]).
Regarding Claim 10, the discussion of Claim 8 is relied upon as above. Wang further teaches patterning the bottom layer using the patterned middle layer and the patterned photosensitive layer as an etch mask and the patterned middle and photosensitive layer are both protected by the protection layer during patterning of the bottom layer (Fig 7 and Fig 8 show the patterning process through to the bottom layer 112).
Regarding Claim 11, the discussion of Claim 8 is relied upon as above. Kanarik further teaches wherein the protection layer does not crosslink the bottom layer during performing the surface treatment (Fig. 2B, the bottom layer does not have deposited material).
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Regarding Claim 13, the limitations of Claim 8 are relied upon as above. Kanarik further teaches patterning the middle layer by comprises hydrogen and a fluorocarbon or hydrofluorocarbon gas (paragraph [0027]).
Regarding Claim 15, the limitations of Claim 8 are replied upon as above. Kanarik further teaches patterning the bottom layer is performed using a combination of hydrogen and CF4 ratios (paragraph [0035]).
Claims 12 and 14 are rejected under 35 U.S.C. 103 as being unpatentable over Wang (US 2019/0385902 A1) in view of Kanarik (US 2006/0089005 A1) and further in view of Tanaka (US 2004/0238486) as applied to Claim 8 and further in view of Xu (US 20090075087 A1).
Regarding Claims 12 and 14, the discussion of Claim 8 is relied upon as above. Wang further discloses anisotropic etching of the middle layer and through the bottom layer (paragraph [0054]-[0055]) and further describes applying dry or wet anisotropic etching processes to layers of the substrate below the tri-layer structure (paragraph [0057]).
Wang does not specify the wet etchant employed being a solution with pH greater than 8 or lower than 5.
However, acidic and basic deep etching solutions are known in the art as disclosed by Xu. Xu discloses broadly that alkaline and acidic etchants may be used for deep etching and vary depending on the desired etch selectivity (paragraph [0004-0005]). Deep etchant solutions can include alkaline etchants such as KOH, TMAH, and NaOH provided in 10-45% solutions and acidic etchants such as concentrated aqueous solutions of HF at 49-50% or dilutions thereof (paragraph [0004-0005]). The pH of a 10% (w/v) NaOH solution is calculated to be 14.40 (the solution is 2.5 M NaOH). The pH of a 50% (w/v) HF solution is calculated to be 0.88 (the solution is 25 M HF).
It would have been obvious for one of ordinary skill in the art to have utilized the wet etchant solutions disclosed by Xu in the wet etching processes of Wang. Wang discloses wet etchant solutions can have low pH or high pH values, depending on the etchant used and the desired selectivity. One of ordinary skill would look to known wet etchant solutions in the art depending on the desired etch selectivity, as disclosed by Xu.
Claims 16-19 are rejected under 35 U.S.C. 103 as being unpatentable over Wang (US 2019/0385902 A1) in view of Tanaka (US 2004/0238486) further in view of Lee (US 2015/0118852).
Regarding Claim 16, Wang teaches a method comprising forming a tri-layer structure over a substrate comprising a bottom, middle, and photosensitive layer formed over a finFET film stack as the semiconductor substrate (Fig. 1, paragraph [0013]-0018]). The photosensitive layer is patterned (Fig. paragraph [0019]) and a surface treatment is performed on the patterned photosensitive layer to form a non-conformal protection layer over the patterned photoresist layer to protect the mask during descum process (Fig. 2, paragraph [0053]). The middle layer and bottom layers are patterned after performing the surface treatment using an etching process, whereby the upper layer may be consumed (Claim 7) (Fig. 7 and Fig. 8, paragraph [0054-0055]) and the substrate is etched (Fig. 13, paragraph [0058]). The patterned mask with the protective film is used as an etching mask for patterning the underlayers (paragraph [0064]) and to further preserve the critical dimensions and reduce the width of a trench between the etch masks (paragraph [0062]).
Wang is silent to wherein the surface treatment forms a protection layer cross-linking the patterned photosensitive layer but not cross-linking the middle layer, and wherein the protection layer is a conformal layer.
However, Tanaka teaches a method to improve etching resistance of an etching mask by forming a protection layer containing a crosslinking agent that is insoluble in a developer containing water (abstract). The etching protection layer is formed at the interface of the resist pattern by applying a heating step to diffuse acid from the resist pattern to activate a crosslinking agent in the protection layer, hardening the layer over the resist pattern (paragraph [0024]). The protected resist pattern is then developed with water to remove the uncrosslinked protection layer (paragraph [0034]) followed by baking [0034]. The crosslinkable compositions improve etching resistance of a resist mask such that a good pattern can be transferred to the substrate in a short time (paragraph [0056]). One example of a crosslinker composition include the solvents 2-propanol and water and the crosslinker methoxymethylated melamine, which is contains 6 alkoxy (-OCH3) substituents (paragraph [0048]). Tanaka further discloses embodiments of the crosslinking agent for forming an etching protection layer may comprise low molecular weight urea derivatives such as methoxymethylurea, dimethylolurea, ethylene urea, ethoxymethyl urea resins, and others and that these crosslinking agents may be used singly or in a mixture or two or more kinds (paragraph [0020]).
The non-conformal layer of Wang serves the same purpose as the crosslinkable protection layer of Tanaka. Each layer provides etching resistance during etching of underlayers. It would have been obvious for one of ordinary skill in the art to have substituted the non-conformal layer of Wang with the crosslinkable layer of Tanaka through routine experimentation with the reasonable expectation of forming a etch-resistant protection layer.
Regarding the crosslinkable composition being organic and alkyl, Tanaka discloses amine-containing crosslinkers that are both aromatic and alkyl as equivalents for one another, such as the melamine resins and the urea resins. It would have been obvious for one of ordinary skill in the art to have substituted the melamine resins with the alkylurea resins through routine experimentation. One of ordinary skill would reasonably expect this modification to result in a crosslinkable protection layer having similar properties.
Tanaka does not explicitly demonstrate that the crosslinkable layer would be a conformal layer.
Nevertheless, Examiner brings in Lee to demonstrate the capping composition is cross-linked after a baking process using the residual acid in the photoresist layer and does not crosslink the middle layer (Fig. 6 and Fig. 7, paragraph [0060]). This capping layer formed on the photoresist pattern is used as an etch mask (paragraph [0022]) to prevent degradation of etch resistance (paragraph [0088]). Further, Lee discloses the substrate may include an etching target layer for the photoresist to be applied on (Fig. 8, the capping layer 145 prevents degradation of the resist pattern during etching of the target layer 110). As shown in Fig. 7, the capping composition is a conformal layer.
Both Tanaka and Lee rely on crosslinkable compositions that react to residual acid remaining in the photoresist layer to form a protecting layer overlying only the surface of the photoresist layer to improve etch resistance and use the photoresist pattern as an etch mask. Lee specifically demonstrates that the crosslinkable compositions reacting onto the photoresist layer form conformal layers. Thus, one of ordinary skill would envisage that the act of crosslinking the composition of Tanaka onto the photoresist layer would form a conformal layer as demonstrated by Lee.
Regarding Claim 17, the limitations of Claim 16 are applied as above. Wang further teaches wherein the photosensitive layer comprises a photoresist (Fig. 1, paragraph [0018] describes the layers and wherein the upper layer is a photosensitive material). Lee also teaches the photosensitive layer comprises a photoresist (paragraph [0018])
Regarding Claim 18, the limitations of Claim 16 are applied as above. Lee further teaches the capping layer and the photoresist pattern may be removed by an ashing and strip process (paragraph [0074]).
Regarding Claim 19, the limitations of Claim 16 are applied as above. Tanaka further discloses the protection layer is coated on the positive-working pattern; the coating process is interpreted as the claimed dispensing.
Response to Arguments
Applicant’s arguments, see the remarks filed 12/30/2025, with respect to 35 USC 103 rejections have been considered but are not persuasive.
In response to applicant's arguments against the references individually, one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986).
Applicant argues that Wang does not teach the amended step of “after performing the surface treatment… performing a rinsing process to remove an unreacted portion of the protection layer” (amending “photosensitive” to “protection”, not to “photosensitive protection” as asserted on p. 9). The argument is unconvincing because Tanaka teaches rinsing with water to remove an unreacted portion of the protection layer after it has been provided [0034].
Regarding claim 8, Applicant argues that Kanarik does not teach using a mixture of a cross-linkable composition and a solvent. The argument is unconvincing because it does not address the combination of references. Tanaka teaches this feature. Applicant argues that Tanaka does not teach protecting the middle layer. The argument is unconvincing because Kanarik teaches the feature of protecting an additional layer below the photoresist.
Regarding claim 16, Applicant argues that Lee doesn’t teach baking after the rinsing process. The argument is unconvincing because Tanaka does [0034].
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to MICHAEL B CLEVELAND whose telephone number is (571)272-1418. The examiner can normally be reached Monday-Friday; 9:00 am - 5:30 pm.
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/MICHAEL B CLEVELAND/ Supervisory Patent Examiner, Art Unit 1712
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