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 .
Information Disclosure Statement
The information disclosure statement(s) submitted on August 19, 2024;August 27, 2024; and June 12, 2025 is/are in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statement(s) is/are being considered by the examiner.
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.
Claim(s) 1-4, 15 and 17-19 is/are rejected under 35 U.S.C. 103 as being unpatentable over US 2009/0181538 A1 (hereinafter “Kojima”) in view of US 2017/0110368 A1 (hereinafter “Yu”).
Regarding claim 1, Kojima discloses a method of microfabrication ([0028]), the method comprising:
providing a wafer (W; [0028]) comprising a dielectric layer (81; [0029]) having an opening (800; [0031]) formed in the dielectric layer, the opening including a bottom and a sidewall (Fig. 1B);
forming a buffer film (83; [0017], [0032] and [0061]) along the bottom and the sidewall of the opening (Fig. 1C); and
forming a metal material (84; [0032]) over the buffer film to fill the opening (Fig. 1D), wherein
a first coefficient of thermal expansion (CTE) α1 of the dielectric layer (about 20 ppm/K = 20×10-6/K for SiOC, as evidenced by US 2012/0075922 A1 in [0095]) is larger than a second CTE α2 of the buffer film (between 6.78×10-6/K and 12×10-6/K for RuOx according to [0042] of Applicant’s specification).
Kojima does not disclose the second CTE α2 of the buffer film is larger than a third CTE α3 of the metal material.
Yu teaches replacing copper (Cu) metal with ruthenium (Ru) metal for a 5 nm technology node ([0020]).
Cu has a CTE of 16.5×10-6/K. Ru has a CTE of 6.78×10-6/K according to [0042] of Applicant’s specification.
Kojima and Yu are analogous art because they both are directed to interconnects for semiconductor devices and one of ordinary skill in the art would have had a reasonable expectation of success to modify Kojima with the specified features of Yu because they are from the same field of endeavor.
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to replace copper (Cu) with ruthenium (Ru) in Kojima’s metal line (84), as taught by Yu, because of the short effective electron mean free path of Ru metal, making it less affected by downward scaling of feature sizes compared to Cu metal (Yu [0020]).
Therefore, Kojima and Yu in combination teach the second CTE α2 of the buffer film is larger than a third CTE α3 of the metal material.
Furthermore, the Supreme Court in KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 415-421, 82 USPQ2d 1385, 1395-97 (2007) identified a number of rationales to support a conclusion of obviousness which are consistent with the proper functional approach to the determination of obviousness as laid down in Graham. The simple substitution of one known element for another to obtain predictable results is an exemplary rationale that may support a conclusion of obviousness. MPEP 2143(I)(B).
Furthermore, it has been held to be within the general skill of a worker in the art to select a known material on the basis of its suitability for the intended use as a matter of obvious design choice. In re Leshin, 277 F.2d 197, 125 USPQ 416 (CCPA 1960). MPEP 2144.07.
Furthermore, it has been held that the test for obviousness is what the combined teachings of the prior art references would have suggested to those of ordinary skill in the art. In re Keller, 642 F.2d 413, 425, 208 USPQ 871, 881 (CCPA 1981). MPEP 2145(III).
Regarding claim 2, Kojima in view of Yu disclose the buffer film comprises a first chemical element (Ru) corresponding to the metal material and a second chemical element (O) that is different from the first chemical element (Kojima [0017] and [0061]).
Regarding claim 3, Kojima in view of Yu disclose the buffer film comprises a compound (RuOx) including the first chemical element and the second chemical element (Kojima [0017] and [0061]).
Regarding claim 4, Kojima in view of Yu disclose the metal material includes ruthenium (Kojima as modified by Yu), and the compound includes ruthenium oxide, ruthenium nitride or both (Kojima [0017] and [0061]).
Regarding claim 15, Kojima in view of Yu disclose the metal material includes one selected from the group consisting of ruthenium and molybdenum (Kojima as modified by Yu).
Regarding claim 17, Kojima in view of Yu disclose α2 = xα1+(1-x)α3, where x is a number of 0.3-1 (when α1=20×10-6/K, α2=11×10-6/K, and α3=6.78×10-6/K, then x=0.32).
Regarding claim 18, Kojima discloses in Fig. 1D and related text a semiconductor device ([0028]), comprising:
a substrate (a semiconductor wafer; [0002]);
a dielectric layer (81; [0029]) formed over the substrate;
a metal material (84; [0032]) formed in the dielectric layer; and
a buffer film (83; [0032]) formed between the metal material and the dielectric layer, wherein a first coefficient of thermal expansion (CTE) α1 of the dielectric layer (about 20 ppm/K = 20×10-6/K for SiOC, as evidenced by US 2012/0075922 A1 in [0095]) is larger than a second CTE α2 of the buffer film (between 6.78×10-6/K and 12×10-6/K for RuOx according to [0042] of Applicant’s specification).
Kojima does not disclose the second CTE α2 of the buffer film is larger than a third CTE α3 of the metal material.
Yu teaches replacing copper (Cu) metal with ruthenium (Ru) metal for a 5 nm technology node ([0020]).
Cu has a CTE of 16.5×10-6/K. Ru has a CTE of 6.78×10-6/K according to [0042] of Applicant’s specification.
Kojima and Yu are analogous art because they both are directed to interconnects for semiconductor devices and one of ordinary skill in the art would have had a reasonable expectation of success to modify Kojima with the specified features of Yu because they are from the same field of endeavor.
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to replace copper (Cu) with ruthenium (Ru) in Kojima’s metal line (84), as taught by Yu, because of the short effective electron mean free path of Ru metal, making it less affected by downward scaling of feature sizes compared to Cu metal (Yu [0020]).
Therefore, Kojima and Yu in combination teach the second CTE α2 of the buffer film is larger than a third CTE α3 of the metal material.
Furthermore, the Supreme Court in KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 415-421, 82 USPQ2d 1385, 1395-97 (2007) identified a number of rationales to support a conclusion of obviousness which are consistent with the proper functional approach to the determination of obviousness as laid down in Graham. The simple substitution of one known element for another to obtain predictable results is an exemplary rationale that may support a conclusion of obviousness. MPEP 2143(I)(B).
Furthermore, it has been held to be within the general skill of a worker in the art to select a known material on the basis of its suitability for the intended use as a matter of obvious design choice. In re Leshin, 277 F.2d 197, 125 USPQ 416 (CCPA 1960). MPEP 2144.07.
Furthermore, it has been held that the test for obviousness is what the combined teachings of the prior art references would have suggested to those of ordinary skill in the art. In re Keller, 642 F.2d 413, 425, 208 USPQ 871, 881 (CCPA 1981). MPEP 2145(III).
Regarding claim 19, Kojima in view of Yu disclose the metal material comprises ruthenium (Kojima as modified by Yu), and the buffer film comprises ruthenium oxide, ruthenium nitride, a ruthenium-aluminum alloy or a ruthenium-cobalt alloy (Kojima [0017] and [0061]).
Claim(s) 5 and 6 is/are rejected under 35 U.S.C. 103 as being unpatentable over Kojima in view of Yu as applied to claim 2 above, and further in view of US 2007/0148952 A1 (hereinafter “O’Brien”).
Regarding claim 5, Kojima in view of Yu disclose the method of claim 2.
Kojima in view of Yu do not disclose the buffer film comprises an alloy including the first chemical element and the second chemical element.
O’Brien teaches in Fig. 2 and related text the buffer film (108; [0026]) comprises an alloy including the first chemical element (Ru) and the second chemical element (Co).
Kojima, Yu and O’Brien are analogous art because they each are directed to interconnects for semiconductor devices and one of ordinary skill in the art would have had a reasonable expectation of success to modify Kojima in view of Yu with the specified features of O’Brien because they are from the same field of endeavor.
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 buffer film to comprise an alloy including the first chemical element and the second chemical element, as taught by O’Brien, in order to utilize the buffer film as a diffusion barrier layer (O’Brien [0026]).
Regarding claim 6, Kojima in view of Yu, and further in view of O’Brien, disclose the method of claim 5, including the metal material includes ruthenium (Kojima as modified by Yu).
Kojima in view of Yu do not disclose the second chemical element includes aluminum, cobalt or both.
O’Brien teaches the second chemical element includes aluminum, cobalt or both ([0026]).
Kojima, Yu and O’Brien are analogous art because they each are directed to interconnects for semiconductor devices and one of ordinary skill in the art would have had a reasonable expectation of success to modify Kojima in view of Yu, and further in view of O’Brien, with the specified features of O’Brien because they are from the same field of endeavor.
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to select as the second chemical element aluminum, cobalt or both, as taught by O’Brien, in order to utilize the buffer film as a diffusion barrier layer (O’Brien [0026]).
Furthermore, it has been held to be within the general skill of a worker in the art to select a known material on the basis of its suitability for the intended use as a matter of obvious design choice. In re Leshin, 277 F.2d 197, 125 USPQ 416 (CCPA 1960). MPEP 2144.07.
Claim(s) 7 is/are rejected under 35 U.S.C. 103 as being unpatentable over Kojima in view of Yu as applied to claim 1 above, and further in view of US 2004/0051117 A1 (hereinafter “Chyan”).
Regarding claim 7, Kojima in view of Yu disclose the method of claim 1.
Kojima in view of Yu do not disclose executing a first physical vapor deposition (PVD) process to form the buffer film comprising ruthenium oxide.
Chyan teaches in Fig. 2 and related text executing a first physical vapor deposition (PVD) process to form the buffer film (22; [0023] and claim 6) comprising ruthenium oxide.
Kojima, Yu and Chyan are analogous art because they each are directed to interconnects for semiconductor devices and one of ordinary skill in the art would have had a reasonable expectation of success to modify Kojima in view of Yu with the specified features of Chyan because they are from the same field of endeavor.
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to execute a first physical vapor deposition (PVD) process to form the buffer film comprising ruthenium oxide, as taught by Chyan, in order to leverage advantages of PVD including superior durability of deposited films, precise control of film thickness, and relatively low processing temperature.
Claim(s) 8 and 9 is/are rejected under 35 U.S.C. 103 as being unpatentable over Kojima in view of Yu, further in view of Chyan, as applied to claim 7 above, and further in view of US 2020/0090983 A1 (hereinafter “Lee”).
Regarding claim 8, Kojima in view of Yu, further in view of Chyan, disclose the method of claim 7.
Kojima in view of Yu, further in view of Chyan, do not disclose executing a chemical vapor deposition (CVD) process to form the metal material comprising ruthenium.
Lee teaches in Fig. 3 and related text executing a chemical vapor deposition (CVD) process to form the metal material (130; [0014]) comprising ruthenium.
Kojima, Yu, Chyan and Lee are analogous art because they each are directed to interconnects for semiconductor devices and one of ordinary skill in the art would have had a reasonable expectation of success to modify Kojima in view of Yu, further in view of Chyan, with the specified features of Lee because they are from the same field of endeavor.
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to execute a chemical vapor deposition (CVD) process to form the metal material comprising ruthenium, as taught by Lee, in order to leverage advantages of CVD including high-purity films with exceptional step coverage across complex 3D topographies.
Regarding claim 9, Kojima in view of Yu, further in view of Chyan, and further in view of Lee, disclose the method of claim 8.
Kojima in view of Yu, further in view of Chyan, do not disclose executing a second PVD process to form an initial portion of the metal material that is in contact with the buffer film before executing the CVD process.
Lee teaches in Fig. 3 and related text executing a second PVD process to form an initial portion of the metal material (130; [0014]) before executing the CVD process. (Lee discloses in [0014] that a combination of PVD and CVD may be used to form the ruthenium material 130. One of ordinary skill in the art reading [0014] of Lee would be free to select PVD to form an initial (first) portion of the metal material and to select CVD to form a second portion of the metal material.)
Kojima, Yu, Chyan and Lee are analogous art because they each are directed to interconnects for semiconductor devices and one of ordinary skill in the art would have had a reasonable expectation of success to modify Kojima in view of Yu, further in view of Chyan, and further in view of Lee, with the specified features of Lee because they are from the same field of endeavor.
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to execute a second PVD process to form an initial portion of the metal material before executing the CVD process, as taught by Lee, in order to leverage advantages of PVD including superior durability of deposited films, precise control of film thickness, and relatively low processing temperature.
Therefore, Kojima and Lee in combination teach executing a second PVD process to form an initial portion of the metal material that is in contact with the buffer film before executing the CVD process.
Furthermore, it has been held that the test for obviousness is what the combined teachings of the prior art references would have suggested to those of ordinary skill in the art. In re Keller, 642 F.2d 413, 425, 208 USPQ 871, 881 (CCPA 1981). MPEP 2145(III).
Claim(s) 10 is/are rejected under 35 U.S.C. 103 as being unpatentable over Kojima in view of Yu, further in view of Chyan, as applied to claim 7 above, and further in view of US 5,225,273 (hereinafter “Mikoshiba”).
Regarding claim 10, Kojima in view of Yu, further in view of Chyan, disclose the method of claim 7.
Kojima in view of Yu, further in view of Chyan, do not explicitly disclose executing the first PVD process comprises: vaporizing a ruthenium metal source in a PVD chamber; and introducing an oxygen gas into the PVD chamber.
Mikoshiba teaches executing the first PVD process comprises:
vaporizing a ruthenium metal source in a PVD chamber (col. 11, lines 44-57); and
introducing an oxygen gas into the PVD chamber (col. 11, lines 57-60).
Kojima, Yu, Chyan and Mikoshiba are analogous art because they each are directed to methods of microfabrication and one of ordinary skill in the art would have had a reasonable expectation of success to modify Kojima in view of Yu, further in view of Chyan, with the specified features of Mikoshiba because they are from the same field of endeavor.
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to execute the first PVD process by vaporizing a ruthenium metal source in a PVD chamber and introducing an oxygen gas into the PVD chamber, as taught by Mikoshiba, in order to leverage advantages of PVD including superior durability of deposited films, precise control of film thickness, and relatively low processing temperature.
Claim(s) 11 is/are rejected under 35 U.S.C. 103 as being unpatentable over Kojima in view of Yu, further in view of Chyan, further in view of Mikoshiba, as applied to claim 10 above, and further in view of US 2002/0157945 A1 (hereinafter “Szczyrbowski”).
Regarding claim 11, Kojima in view of Yu, further in view of Chyan, further in view of Mikoshiba, disclose the method of claim 10.
Kojima in view of Yu, further in view of Chyan, further in view of Mikoshiba, do not explicitly disclose the oxygen gas is introduced into the PVD chamber at a constant flow rate.
Szczyrbowski teaches in Fig. 1 and related text the oxygen gas is introduced into the PVD chamber (5; [0013]) at a constant flow rate ([0016]).
Kojima, Yu, Chyan, Mikoshiba and Szczyrbowski are analogous art because they each are directed to methods of microfabrication and one of ordinary skill in the art would have had a reasonable expectation of success to modify Kojima in view of Yu, further in view of Chyan, further in view of Mikoshiba, with the specified features of Szczyrbowski because they are from the same field of endeavor.
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to introduce the oxygen gas into the PVD chamber at a constant flow rate, as taught by Szczyrbowski, in order to deposit a metal oxide thin film having a uniform oxygen concentration.
Claim(s) 13 is/are rejected under 35 U.S.C. 103 as being unpatentable over Kojima in view of Yu as applied to claim 1 above, and further in view of Lee.
Regarding claim 13, Kojima in view of Yu disclose the method of claim 1.
Kojima in view of Yu do not disclose at least one of the buffer film or the metal material is at least partially formed by atomic layer deposition (ALD).
Lee teaches in Fig. 3 and related text the metal material (130; [0014]) is at least partially formed by atomic layer deposition (ALD).
Kojima, Yu and Lee are analogous art because they each are directed to interconnects for semiconductor devices and one of ordinary skill in the art would have had a reasonable expectation of success to modify Kojima in view of Yu with the specified features of Lee because they are from the same field of endeavor.
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to at least partially form the metal material by atomic layer deposition (ALD), as taught by Lee, because ALD enables precise angstrom-level thickness control and perfect conformality on complex 3D topographies.
Claim(s) 14 and 16 is/are rejected under 35 U.S.C. 103 as being unpatentable over Kojima in view of Yu as applied to claim 1 above, and further in view of US 2005/0184397 A1 (hereinafter “Gates”).
Regarding claim 14, Kojima in view of Yu disclose the method of claim 1.
Kojima in view of Yu do not disclose the dielectric layer includes at least one selected from the group consisting of an organosilicate glass, amorphous carbon, porous silicon oxide, a spin-on organic polymeric dielectric, a spin-on silicon-based polymeric dielectric, porous SiOCH, porous poly(arylene ether) and porous methylsilsesquioxane.
Gates teaches in Fig. 2 and related text the dielectric layer (26; [0052]-[0055]) includes at least one selected from the group consisting of an organosilicate glass, amorphous carbon, porous silicon oxide, a spin-on organic polymeric dielectric, a spin-on silicon-based polymeric dielectric, porous SiOCH, porous poly(arylene ether) and porous methylsilsesquioxane.
Kojima, Yu and Gates are analogous art because they each are directed to interconnects for semiconductor devices and one of ordinary skill in the art would have had a reasonable expectation of success to modify Kojima in view of Yu with the specified features of Gates because they are from the same field of endeavor.
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 dielectric layer to include at least one selected from the group consisting of an organosilicate glass, amorphous carbon, porous silicon oxide, a spin-on organic polymeric dielectric, a spin-on silicon-based polymeric dielectric, porous SiOCH, porous poly(arylene ether) and porous methylsilsesquioxane, as taught by Gates, in order to integrate an ultralow-k (ULK) dielectric layer, thereby reducing parasitic capacitance within a back end of the line (BEOL) interconnect structure.
Regarding claim 16, Kojima in view of Yu disclose the method of claim 1.
Kojima in view of Yu do not explicitly disclose the dielectric layer comprises a low-k dielectric having a dielectric constant of 3 or less.
Gates teaches in Fig. 2 and related text the dielectric layer (26; [0051]) comprises a low-k dielectric having a dielectric constant of 3 or less.
Kojima, Yu and Gates are analogous art because they each are directed to interconnects for semiconductor devices and one of ordinary skill in the art would have had a reasonable expectation of success to modify Kojima in view of Yu with the specified features of Gates because they are from the same field of endeavor.
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 dielectric layer to comprise a low-k dielectric having a dielectric constant of 3 or less, as taught by Gates, in order to reduce parasitic capacitance within a back end of the line (BEOL) interconnect structure.
Claim(s) 20 is/are rejected under 35 U.S.C. 103 as being unpatentable over Kojima in view of Yu as applied to claim 19 above, and further in view of US 5,314,727 (hereinafter “McCormick”).
Regarding claim 20, Kojima in view of Yu disclose the semiconductor device of claim 19, including the buffer film comprises ruthenium oxide (Kojima [0017] and [0061]).
Kojima in view of Yu do not explicitly disclose the buffer film has a uniform oxygen concentration or a non-uniform oxygen concentration that decreases from a first side to a second side, the first side facing the dielectric layer, the second side facing the metal material.
McCormick teaches the buffer film (a ruthenium oxide film) has a uniform oxygen concentration (col. 19, lines 24-27).
Kojima, Yu and McCormick are analogous art because they each are directed to methods of microfabrication and one of ordinary skill in the art would have had a reasonable expectation of success to modify Kojima in view of Yu with the specified features of McCormick because they are from the same field of endeavor.
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 buffer film to have a uniform oxygen concentration, as taught by McCormick, in order to ensure the uniformity of physical properties (e.g., resistivity) of the buffer film.
Allowable Subject Matter
Claim 12 is objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
The following is a statement of reasons for the indication of allowable subject matter: the prior art of record, individually or in combination, does not teach or suggest “the oxygen gas is introduced into the PVD chamber at a decreasing flow rate” as recited in claim 12.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to PETER M ALBRECHT whose telephone number is (571)272-7813. The examiner can normally be reached M-F 9:30 AM - 6:30 PM (CT).
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/PETER M ALBRECHT/Primary Examiner, Art Unit 2811
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