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 Objections
Claims 3, 12 and 19 are objected to because of the following informalities: “electrical work function differential of at least +44.8”, appropriate unit of electrical work function should be recited. Appropriate correction is required.
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.
Claims 1-2, 6-11 and 13-18 are rejected under 35 U.S.C. 103 as being unpatentable over Zhang et al. (US 20210118683 A1; hereafter Zhang) in view of Ando et al. (US 2020/0365584 A1; hereafter Ando).
Regarding claim 1, Zhang teaches a semiconductor device (see e.g., Figures 5-8) comprising:
nanostructures in a multilayer stack (see e.g., nanosheet layer segments 131, Para [0031], Figures 5-8);
an interfacial layer surrounding the nanostructures (see e.g., the gate dielectric layer 160 may comprise silicon oxide (SiO), silicon nitride (SiN), a high-K dielectric material, and combinations thereof. The silicon oxide corresponds to the interfacial layer surrounding the nanostructures, Para [0040], Figures 5-8);
a gate dielectric surrounding the interfacial layer (see e.g., the high-k dielectric material of the gate dielectric 160 surrounds the interfacial layer, Para [0040], Figures 5-8);
a first p-metal work function layer surrounding the gate dielectric (see e.g., work function material layer 170 surrounds the gate dielectric layer 160, Para [0043], Figures 5-8),
Zhang does not explicitly teach
“wherein at least 50%-atomic of the materials of the interfacial layer, the gate dielectric, and the first p-metal work function layer is oxygen”
"[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). Furthermore, "[i]t is a settled principle of law that a mere carrying forward of an original patented conception involving only change of form, proportions, or degree, or the substitution of equivalents doing the same thing as the original invention, by substantially the same means, is not such an invention as will sustain a patent, even though the changes of the kind may produce better results than prior inventions." In re Williams, 36 F.2d 436, 438 (CCPA 1929).
Zhang teaches an interfacial dielectric comprising silicon oxide, a high-k gate dielectric comprising hafnium oxide and a work function material layer comprising an oxygen rich transition metal nitride having an oxygen concentration in a range of about 5 atomic percent (at. %) to 25 at. %, while explicitly indicating that other oxygen concentrations are contemplated.
Zhang teaches that the oxygen concentration of the gate stack affects the threshold voltage of the nanosheet device and may be selected to provide a desired low threshold voltage (see e.g., Paras [0044], [0045]). Accordingly, the oxygen concentration constitutes a result effective variable.
Therefore, it would have been obvious to one skilled in art at the time the invention was effectively filed to optimize the oxygen concentration of the interfacial layer, high-k gate dielectric and the first p-type work function layer to provide a combined oxygen concentration of at least 50 atomic percent in order to obtain a desired work function and thereby control the threshold voltage of the device. Such optimization of a known parameter for its known effect would have involved no more than routine experimentation.
Zhang does not explicitly teach
“a second p-metal work function layer; and
a conductive fill material over the second p-metal work function layer”.
In a similar field of endeavor Ando teaches
a second p-metal work function layer; and (see e.g., liner 18 composed of TiN, WN or other suitable liner material for a PFET device, para [0052], Figure 8)
a conductive fill material over the second p-metal work function layer (see e.g., low resistivity metal 19 deposited over the liner 18, Paras [0053], [0054], Figure 8).
Therefore, it would have been obvious to one skilled in art at the time the invention was effectively filed to implement Ando’s teachings of a second p-metal work function layer; and a conductive fill material over the second p-metal work function layer in the device of Zhang to provide suitable gate work function characteristics and reduced gate resistance.
Regarding claim 2, Zhang, as modified by Ando, teaches the limitations of claim 1 as mentioned above. Zhang further teaches
wherein the first p-metal work function layer comprises a titanium nitride material (see e.g., the work function material layer 170 comprises an oxygen rich transition metal nitride for example, titanium oxynitride, Para [0044], Figures 5-8).
Regarding claim 6, Zhang, as modified by Ando, teaches the limitations of claim 1 as mentioned above. Zhang does not explicitly teach
“wherein less than 54%-atomic of the materials of the interfacial layer, the gate dielectric, and the first p-metal work function layer is oxygen”.
Zhang teaches an interfacial dielectric comprising silicon oxide, a high-k gate dielectric comprising hafnium oxide and a work function material layer comprising an oxygen rich transition metal nitride having an oxygen concentration in a range of about 5 atomic percent (at. %) to 25 at. %, while explicitly indicating that other oxygen concentrations are contemplated.
Zhang teaches that the oxygen concentration of the gate stack affects the threshold voltage of the nanosheet device and may be selected to provide a desired low threshold voltage (see e.g., Paras [0044], [0045]). Accordingly, the oxygen concentration constitutes a result effective variable.
Therefore, it would have been obvious to one skilled in art at the time the invention was effectively filed to optimize the oxygen concentration of the interfacial layer, high-k gate dielectric and the first p-type work function layer to provide a combined oxygen concentration of less than 54 atomic percent in order to obtain a desired work function and thereby control the threshold voltage of the device. Such optimization of a known parameter for its known effect would have involved no more than routine experimentation.
Regarding claim 7, Zhang, as modified by Ando, teaches the limitations of claim 1 as mentioned above. Zhang further teaches
wherein the first p-metal work function layer comprises pockets of oxygen (see e.g., The oxygen rich transition metal nitride work function material maybe formed by introducing an oxygen species and/or by introducing air breaks during the deposition process of the transition metal nitride work function material. Such processing introduces oxygen into portions of the transition metal nitride work function material during thereof.
Accordingly, the oxygen introduced into the transition metal nitride work function material by the disclosed oxygen supplying species and/or air breaks reasonably corresponds to localized oxygen containing regions or pockets of oxygen within the first p-type metal work function layer).
Regarding claim 8, Zhang teaches a semiconductor device (see e.g., Figures 5-8) comprising:
nanostructures in a multilayer stack (see e.g., nanosheet layer segments 131, Para [0031], Figures 5-8);
an interlayer dielectric surrounding the nanostructures (see e.g., the gate dielectric layer 160 may comprise silicon oxide (SiO), silicon nitride (SiN), a high-K dielectric material, and combinations thereof. The silicon oxide corresponds to the interfacial layer surrounding the nanostructures, Para [0040], Figures 5-8);
a gate dielectric surrounding the interlayer dielectric (see e.g., the high-k dielectric material of the gate dielectric 160 surrounds the interfacial layer, Para [0040], Figures 5-8);
a first work function layer surrounding the gate dielectric (see e.g., work function material layer 170 surrounds the gate dielectric layer 160, Para [0043], Figures 5-8),
Zhang does not explicitly teach
“wherein a combination of the interlayer dielectric, the gate dielectric, and the first work function layer has a combined oxygen concentration of greater than 50%-atomic;”
"[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). Furthermore, "[i]t is a settled principle of law that a mere carrying forward of an original patented conception involving only change of form, proportions, or degree, or the substitution of equivalents doing the same thing as the original invention, by substantially the same means, is not such an invention as will sustain a patent, even though the changes of the kind may produce better results than prior inventions." In re Williams, 36 F.2d 436, 438 (CCPA 1929).
Zhang teaches an interfacial dielectric comprising silicon oxide, a high-k gate dielectric comprising hafnium oxide and a work function material layer comprising an oxygen rich transition metal nitride having an oxygen concentration in a range of about 5 atomic percent (at. %) to 25 at. %, while explicitly indicating that other oxygen concentrations are contemplated.
Zhang teaches that the oxygen concentration of the gate stack affects the threshold voltage of the nanosheet device and may be selected to provide a desired low threshold voltage (see e.g., Paras [0044], [0045]). Accordingly, the oxygen concentration constitutes a result effective variable.
Therefore, it would have been obvious to one skilled in art at the time the invention was effectively filed to optimize the oxygen concentration of the interfacial layer, high-k gate dielectric and the first p-type work function layer to provide a combined oxygen concentration of at least 50 atomic percent in order to obtain a desired work function and thereby control the threshold voltage of the device. Such optimization of a known parameter for its known effect would have involved no more than routine experimentation.
Zhang does not explicitly teach
“a second work function layer adjacent the first work function layer; and
a gate electrode stack with a conductive fill material over the second work function layer”.
In a similar field of endeavor Ando teaches
a second work function layer adjacent the first work function layer; and (see e.g., liner 18 composed of TiN, WN or other suitable liner material for a PFET device adjacent the work function metal 16, para [0052], Figure 8)
a gate electrode stack with a conductive fill material over the second work function layer (see e.g., low resistivity metal 19 deposited over the liner, Paras [0053], [0054], Figure 8).
Therefore, it would have been obvious to one skilled in art at the time the invention was effectively filed to implement Ando’s teachings of a second work function layer adjacent the first work function layer; and a gate electrode stack with a conductive fill material over the second work function layer in the device of Zhang to provide suitable gate work function characteristics and reduced gate resistance.
Regarding claim 9, Zhang, as modified by Ando, teaches the limitations of claim 8 as mentioned above. Zhang further teaches
wherein the interlayer dielectric comprises silicon oxide (see e.g., gate dielectric layer 160 comprises silicon oxide, Para [0040], Figures 5-8).
Regarding claim 10, Zhang, as modified by Ando, teaches the limitations of claim 8 as mentioned above. Zhang further teaches
wherein the gate dielectric comprises a hafnium oxide material (see e.g., the gate dielectric layer 160 comprises high-k dielectric material such as hafnium oxide, Para [0040], Figures 5-8).
Regarding claim 11, Zhang, as modified by Ando, teaches the limitations of claim 8 as mentioned above. Zhang further teaches
wherein the first work function layer comprises a titanium nitride material (see e.g., the work function material layer 170 comprises an oxygen rich transition metal nitride for example, titanium oxynitride, Para [0044], Figures 5-8).
Regarding claim 13, Zhang, as modified by Ando, teaches the limitations of claim 8 as mentioned above. Zhang does not explicitly teach
“wherein the combination of the interlayer dielectric, the gate dielectric, and the first work function layer has a combined oxygen concentration of less than 54%-atomic”.
Zhang teaches an interfacial dielectric comprising silicon oxide, a high-k gate dielectric comprising hafnium oxide and a work function material layer comprising an oxygen rich transition metal nitride having an oxygen concentration in a range of about 5 atomic percent (at. %) to 25 at. %, while explicitly indicating that other oxygen concentrations are contemplated.
Zhang teaches that the oxygen concentration of the gate stack affects the threshold voltage of the nanosheet device and may be selected to provide a desired low threshold voltage (see e.g., Paras [0044], [0045]). Accordingly, the oxygen concentration constitutes a result effective variable.
Therefore, it would have been obvious to one skilled in art at the time the invention was effectively filed to optimize the oxygen concentration of the interfacial layer, high-k gate dielectric and the first p-type work function layer to provide a combined oxygen concentration of less than 54 atomic percent in order to obtain a desired work function and thereby control the threshold voltage of the device. Such optimization of a known parameter for its known effect would have involved no more than routine experimentation.
Regarding claim 14, Zhang, as modified by Ando, teaches the limitations of claim 8 as mentioned above. Zhang further teaches
wherein the first work function layer comprises pockets of oxygen (see e.g., The oxygen rich transition metal nitride work function material maybe formed by introducing an oxygen species and/or by introducing air breaks during the deposition process of the transition metal nitride work function material. Such processing introduces oxygen into portions of the transition metal nitride work function material during thereof.
Accordingly, the oxygen introduced into the transition metal nitride work function material by the disclosed oxygen supplying species and/or air breaks reasonably corresponds to localized oxygen containing regions or pockets of oxygen within the first p-type metal work function layer).
Regarding claim 15, Zhang teaches a semiconductor device (see e.g., Figures 5-8) comprises:
a nanostructure stack (see e.g., nanosheet layer segments 131, Para [0031], Figures 5-8);
a base structure of a gate stack, the base structure comprising:
an interlayer dielectric surrounding each nanostructure of the nanostructure stack (see e.g., the gate dielectric layer 160 may comprise silicon oxide (SiO), silicon nitride (SiN), a high-K dielectric material, and combinations thereof. The silicon oxide corresponds to the interfacial layer surrounding the nanostructures, Para [0040], Figures 5-8);
a gate dielectric surrounding the interlayer dielectric; and (see e.g., the high-k dielectric material of the gate dielectric 160 surrounds the interfacial layer, Para [0040], Figures 5-8)
a first p-metal work function layer (see e.g., work function material layer 170 surrounds the gate dielectric layer 160, Para [0043], Figures 5-8),
Zhang does not explicitly teach
“the base structure having a composition that is greater than 50% oxygen by atomic weight;”
"[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). Furthermore, "[i]t is a settled principle of law that a mere carrying forward of an original patented conception involving only change of form, proportions, or degree, or the substitution of equivalents doing the same thing as the original invention, by substantially the same means, is not such an invention as will sustain a patent, even though the changes of the kind may produce better results than prior inventions." In re Williams, 36 F.2d 436, 438 (CCPA 1929).
Zhang teaches an interfacial dielectric comprising silicon oxide, a high-k gate dielectric comprising hafnium oxide and a work function material layer comprising an oxygen rich transition metal nitride having an oxygen concentration in a range of about 5 atomic percent (at. %) to 25 at. %, while explicitly indicating that other oxygen concentrations are contemplated.
Zhang teaches that the oxygen concentration of the gate stack affects the threshold voltage of the nanosheet device and may be selected to provide a desired low threshold voltage (see e.g., Paras [0044], [0045]). Accordingly, the oxygen concentration constitutes a result effective variable.
Therefore, it would have been obvious to one skilled in art at the time the invention was effectively filed to optimize the oxygen concentration of the interfacial layer, high-k gate dielectric and the first p-type work function layer to provide a combined oxygen concentration of at least 50 atomic percent in order to obtain a desired work function and thereby control the threshold voltage of the device. Such optimization of a known parameter for its known effect would have involved no more than routine experimentation.
Zhang does not explicitly teach
“a top structure of the gate stack, the top structure comprising a second p-metal work function layer surrounding the first p-metal work function layer and a conductive fill material disposed over the second p-metal work function layer”.
In a similar field of endeavor Ando teaches
a top structure of the gate stack, the top structure comprising a second p-metal work function layer surrounding the first p-metal work function layer (see e.g., liner 18 composed of TiN, WN or other suitable liner material for a PFET device surrounding the work function metal 16, para [0052], Figure 8)
and a conductive fill material disposed over the second p-metal work function layer (see e.g., low resistivity metal 19 deposited over the liner, Paras [0053], [0054], Figure 8).
Therefore, it would have been obvious to one skilled in art at the time the invention was effectively filed to implement Ando’s teachings of a top structure of the gate stack, the top structure comprising a second p-metal work function layer surrounding the first p-metal work function layer and a conductive fill material disposed over the second p-metal work function layer in the device of Zhang to provide suitable gate work function characteristics and reduced gate resistance.
Regarding claim 16, Zhang, as modified by Ando, teaches the limitations of claim 15 as mentioned above. Zhang further teaches
wherein the interlayer dielectric comprises a silicon oxide material (see e.g., gate dielectric layer 160 comprises silicon oxide, Para [0040], Figures 5-8).
Regarding claim 17, Zhang, as modified by Ando, teaches the limitations of claim 16 as mentioned above. Zhang further teaches
wherein the gate dielectric comprises a hafnium oxide material (see e.g., the gate dielectric layer 160 comprises high-k dielectric material such as hafnium oxide, Para [0040], Figures 5-8).
Regarding claim 18, Zhang, as modified by Ando, teaches the limitations of claim 17 as mentioned above. Zhang further teaches
wherein the first p-metal work function layer comprises a titanium nitride material (see e.g., the work function material layer 170 comprises an oxygen rich transition metal nitride for example, titanium oxynitride, Para [0044], Figures 5-8).
Claims 3-5, 12 and 19-20 are rejected under 35 U.S.C. 103 as being unpatentable over Zhang et al. (US 20210118683 A1; hereafter Zhang) in view of Ando et al. (US 2020/0365584 A1; hereafter Ando) and further in view of Hinkle et al.; Interfacial oxygen and nitrogen induced dipole formation and vacancy passivation for increased effective work functions in TiN/Hf
O
2
gate stacks. Appl. Phys. Lett. 8 March 2010; 96 (10): 103502. https://doi.org/10.1063/1.3353993; hereafter Hinkle
Regarding claims 3 and 19, Zhang, as modified by Ando, teaches the limitations of claim 2 and claim 15 as mentioned above. Zhang does not explicitly teach
“wherein an interface between the first p-metal work function layer and the gate dielectric has an electrical work function differential of at least +44.8”.
"[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). Furthermore, "[i]t is a settled principle of law that a mere carrying forward of an original patented conception involving only change of form, proportions, or degree, or the substitution of equivalents doing the same thing as the original invention, by substantially the same means, is not such an invention as will sustain a patent, even though the changes of the kind may produce better results than prior inventions." In re Williams, 36 F.2d 436, 438 (CCPA 1929).
In a similar field of endeavor Hinkle teaches a TiN work function metal adjacent to an HfO.sub.2 gate dielectric and teaches annealing the TiN/HfO.sub.2 gate stack under conditions that incorporate oxygen into the TiN near the TiN/HfO.sub.2 interface. Hinkle further teaches incorporation of oxygen into the TiN increases the effective work function of the gate stack and reports an effective work function increase of 500meV.
Therefore, it would have been obvious to one skilled in the art at the time the invention was effectively filed to optimize oxygen concentration in a TiN based work function material adjacent to a high-k dielectric to modify the effective work function and threshold voltage characteristics of the device.
Regarding claim 4, Zhang, as modified by Ando, teaches the limitations of claim 3 as mentioned above. Zhang further teaches
wherein the interfacial layer comprises a silicon oxide material (see e.g., gate dielectric layer 160 comprises silicon oxide, Para [0040], Figures 5-8).
Regarding claim 5, Zhang, as modified by Ando, teaches the limitations of claim 4 as mentioned above. Zhang further teaches
wherein the gate dielectric comprises a hafnium oxide material (see e.g., the gate dielectric layer 160 comprises high-k dielectric material such as hafnium oxide, Para [0040], Figures 5-8).
Regarding claim 12, Zhang, as modified by Ando, teaches the limitations of claim 8 as mentioned above. Zhang does not explicitly teach
“wherein an interface between the first work function layer and the gate dielectric has an electrical work function differential of at least +44.8”.
"[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). Furthermore, "[i]t is a settled principle of law that a mere carrying forward of an original patented conception involving only change of form, proportions, or degree, or the substitution of equivalents doing the same thing as the original invention, by substantially the same means, is not such an invention as will sustain a patent, even though the changes of the kind may produce better results than prior inventions." In re Williams, 36 F.2d 436, 438 (CCPA 1929).
In a similar field of endeavor Hinkle teaches a TiN work function metal adjacent to an HfO.sub.2 gate dielectric and teaches annealing the TiN/HfO.sub.2 gate stack under conditions that incorporate oxygen into the TiN near the TiN/HfO.sub.2 interface. Hinkle further teaches incorporation of oxygen into the TiN increases the effective work function of the gate stack and reports an effective work function increase of 500meV.
Therefore, it would have been obvious to one skilled in art at the time the invention was effectively filed to optimize oxygen concentration in a TiN based work function material adjacent to a high-k dielectric to modify the effective work function and threshold voltage characteristics of the device.
Regarding claim 20, Zhang, as modified by Ando, teaches the limitations of claim 15 as mentioned above. Zhang does not explicitly teach
“wherein an electrical work function of the first p-metal work function layer is shifted towards a P-band edge”.
In a similar field of endeavor Hinkle teaches a TiN work function metal adjacent an HfO.sub.2 gate dielectric and teaches annealing the TiN/HfO.sub.2 gate stack under conditions that incorporate oxygen into the TiN near the TiN/HfO.sub.2 interface. Hinkle further teaches incorporation of oxygen into the TiN increases the effective work function of the gate stack and reports an effective work function increase of 500meV.
Therefore, it would have been obvious to one skilled in art at the time the invention was effectively filed to incorporate oxygen into the p-type metal work function metal layer. By introducing oxygen into the p-type metal work function layer its effective work function is increased causing it to shift predictably toward the p-type band edge. This material modification directly optimizes the electrical properties of the device thereby proving the highly desirable threshold voltage characteristics required of high performance PFET operation.
Conclusion
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/FAKEHA SEHAR/ Examiner, Art Unit 2893
/YARA B GREEN/ Supervisor Patent Examiner, Art Unit 2893
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