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 .
DETAILED ACTION
Claims 1-3, 5-6, 9, 12-14, 16-18, and 20-23 of C. Winter et al., US 16/934,514 (July 21, 2020) are pending and are rejected.
Provisional Election of Species
Pursuant to the Election of Species Requirement, Applicant previously elected Co(thd)2, which has the following structure.
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Claims 1-3, 5-7, 9, 12-18, and 20-22 read on the elected species. The elected species was searched and determined to be unpatentable under § 103 over the cited art. Pursuant to MPEP § 803.02, the search was not extended to additional species. Accordingly, the provisional election of species requirement is maintained in effect and no claims are provisionally withdrawn from consideration pursuant to 37 CFR 1.142(b). See, MPEP § 803.02.
Claim Interpretation
Examination requires claim terms first be construed in terms in the broadest reasonable manner during prosecution as is reasonably allowed in an effort to establish a clear record of what applicant intends to claim. See, MPEP § 2111. During patent examination, the pending claims must be "given their broadest reasonable interpretation consistent with the specification. MPEP § 2111.
Interpretation of the Claim 1 and Claim 16 Term “inert atmosphere”
The specification does not define “inert atmosphere” in the context of annealing step (c), nor give any examples (working or otherwise) of an inert atmosphere for annealing step (c). Clearly the specification’s disclosed annealing purpose is to remove/decompose any undesired carbon and nitrogen species from the formed cobalt film. Specification at page 22, [0100]. As such, the specification’s undisclosed annealing atmosphere is not inert, at least with respect to carbon and nitrogen species.
In the absence of a speciation definition, the term “inert atmosphere”, in the context of claim 1 and claim 16 annealing step (c), is broadly and reasonably interpreted, consistently with the specification, as any atmosphere in which the elemental Co0 is unreactive at the particular annealing temperature. MPEP § 2111; specification at page 22, [0100].
Claim Rejections 35 U.S.C. 112(a) -- New Matter
The following is a quotation of the first paragraph of 35 U.S.C. 112(a):
(a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.
Amendments narrowing the claims by introducing elements or limitations which are not supported by the as-filed disclosure is a violation of the written description requirement of 35 U.S.C. 112(a). MPEP § 2163.05(II). Ipsis verbis disclosure is not necessary to satisfy the written description requirement; If a skilled artisan would have understood the inventor to be in possession of the claimed invention at the time of filing, even if every nuance of the claims is not explicitly described in the specification, then the adequate description requirement is met. MPEP § 2163(II)(A)(3)(a) (citing Vas-Cath, Inc. v. Mahurkar, 935 F.2d 1555, 1560, 19 USPQ2d 1111, 1114 (Fed. Cir. 1991).
The Claim 1 Amended Term “inert atmosphere” Is New Matter
Independent claims 1 and 16 (and their dependent claims 2-3, 5-6, 9, 12-14, 17-18, and 20-23) are rejected under 35 U.S.C. 112(a) as failing to comply with the written description requirement because the claim 1 and 16 term “inert atmosphere”, in the context claim 1, step (c), is not supported by the application as filed, and is therefore new matter.
Claims 1 and 16 . . . c) annealing the metal-containing film at a second predetermined temperature that is less than 400 °C in an inert atmosphere for a sufficient time that carbon and nitrogen are not detected by XPS within instrument sensitivity and the metal-containing film includes the metal atom in the zero oxidation state in an amount greater than 98 mole percent . . .
This limitation is not recited literally in application as filed.
Applicant cites the following portion for § 112(a) support of subject limitation:
In conclusion, cobalt metal has been deposited using Co(thd)2 and 1,1-dimethyl hydrazine. GI-XRD analysis of a film grown on copper was consistent with cobalt metal or cobalt-copper alloy, XPS data indicated low levels of carbon, nitrogen, and oxygen in films deposited at various temperatures and treatment of a film with a post-deposition anneal resulted in a high-quality film with no carbon or nitrogen impurities.
Reply at page 8 (citing the specification at page 22, [0100]) (emphasis added by Applicant). This cited specification excerpt references the specification “Experimental” section, where specification Figs. 2-15 represent the results of various analytical experiments on the films produced by atomic layer deposition of precursor species Co(thd)2, Co(hfac)2(TMEDA), Co(hfac)2(TEEDA), Co(hfac)2(TMPDA). See specification “Experimental” at pages 23-24, [0101]-[0105]; for the precursor’s chemical structures, see specification Fig. 3A.
The amended claim 1 and 16 term “inert atmosphere” in the claim’s context of annealing step (c) does not appear in the above specification excerpt cited by Applicant nor anywhere else in the specification. The Examiner can find no literal or inferred supporting disclosure for the subject claim amendment in the application as filed. See e.g., Specification at page 21, [0096] (disclosing a post-deposition anneal at 400 °C on cobalt metal film deposited from Co(thd)2 where the annealing atmosphere is not disclosed); MPEP 2163.04(I) (citing Hyatt v. Dudas, 492 F.3d 1365, 1370, n.4 (Fed. Cir. 2007)); MPEP § 2163(II)(A).
The Claim 1 and 16 Amended Term “for a sufficient time that carbon and nitrogen are not detected by XPS within instrument sensitivity” Is New Matter
Independent claims 1 and 16 (and their dependent claims 2-3, 5-6, 9, 12-14, 17-18, and 20-23) are rejected under 35 U.S.C. 112(a) as failing to comply with the written description requirement because the claim 1 and 16 term “a sufficient time” in the context of “for a sufficient time that carbon and nitrogen are not detected by XPS”, in the context claim 1, step (c), is not supported by the application as filed, and is therefore new matter.
Claims 1 and 16. . . c) annealing the metal-containing film at a second predetermined temperature that is less than 400 °C in an inert atmosphere for a sufficient time that carbon and nitrogen are not detected by XPS within instrument sensitivity and the metal-containing film includes the metal atom in the zero oxidation state in an amount greater than 98 mole percent . . .
The subject recitation is clearly functional language. MPEP § 2173.05(g). Here, one of skill does not know what the range of “for a sufficient time” encompasses because the specification does not provide a description of a “sufficient time” in the context of annealing step (c); particularly in view of the large claim 1 and 16 genera of formulae (3.1). (3.2) and (3.3). See footnote 1.
Absent literal support, with respect to changing numerical range limitations, an analysis must consider which ranges one skilled in the art would consider inherently supported by the discussion in the original disclosure. MPEP § 2163.05(II)/(III) (citing In re Lukach, 442 F.2d 967, 169 USPQ 795 (CCPA 1971) and In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976)). The issue in In re Lukach was whether the claim limitation of “a Mw/Mn ratio of at least 2.0 and less than about 3.0” is supported by the grandparent specification. In re Lukach, the subject limitation was not expressly recited, but one of the working examples in the grandparent inherently described a copolymer which would have a Mw/Mn ratio of 2.6. The court found that the single example inherently disclosing a copolymer having a Mw/Mn ration of 2.6 does not alone provide support for the recited range from 2.0 to 3.0. MPEP § 2163.05(II)/(III); In re Lukach, 442 F.2d 967, 169 USPQ 795 (CCPA 1971).
Applicant cites the following portion for § 112(a) support of subject limitation:
In conclusion, cobalt metal has been deposited using Co(thd)2 and 1,1-dimethyl hydrazine. GI-XRD analysis of a film grown on copper was consistent with cobalt metal or cobalt-copper alloy, XPS data indicated low levels of carbon, nitrogen, and oxygen in films deposited at various temperatures and treatment of a film with a post-deposition anneal resulted in a high-quality film with no carbon or nitrogen impurities.
Reply at page 8 (citing the specification at page 22, [0100]) (emphasis added by Applicant). The Examiner notes that the specification also discloses the following regarding the claim 1 annealing step is the following:
[0083] In a variation, the method further includes a step of annealing the metal-containing film at a second predetermined temperature for a sufficient time that the metal-containing film includes the metal atom in the zero oxidation state in an amount greater than 98 mole percent. Characteristically, the second predetermined temperature is greater than the first predetermined temperature. In a refinement, the second predetermined temperature is greater than in increasing order of preference, 300 °C, 310 °C, 325 °C, or 330 °C. Typically, the second predetermined temperature is less than about 400 °C.
Specification at page 15, [0083] (emphasis added). Neither of these specification excerpts support the range amendment of “for a sufficient time” to perform the claimed function of “that carbon and nitrogen are not detected by XPS within instrument sensitivity”.1 In fact, the specification does not give a single example of any annealing time (either in the working examples or specification body), let alone an example of an annealing time that performs the function of “that carbon and nitrogen are not detected by XPS within instrument sensitivity”. See e.g., Specification at page 21, [0096] (disclosing a post-deposition anneal at 400 °C on cobalt metal film deposited from Co(thd)2 where the annealing time is not disclosed); MPEP 2163.04(I) (citing Hyatt v. Dudas, 492 F.3d 1365, 1370, n.4 (Fed. Cir. 2007)); MPEP § 2163(II)(A).
In sum, the specification does not provide a single example of an annealing time therefore the range of “for a sufficient time that carbon and nitrogen are not detected by XPS within instrument sensitivity”, in the context of annealing step (c) (particularly in view of the large claim 1 and 16 genera of formulae (3.1). (3.2) and (3.3)) is new matter. MPEP § 2163.05(II)/(III) (citing In re Lukach, 442 F.2d 967, 169 USPQ 795 (CCPA 1971) and In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976)).
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 factual inquiries set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied for establishing a background for determining obviousness under AIA 35 U.S.C. 103(a) 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.
The § 103 Rejection
Claims 1-3, 5-6, 9, 12-14, 16-18, and 20-23 are rejected under AIA 35 U.S.C. 103 as being unpatentable over C. Winter et al., US 2015/0004314 (2015) (“the ‘314 publication” or “Winter”) and S. Haukka et al., US 2019/0252195 (2019) (“Haukka”); and S. Lee et al., US 2021/0032279 (2021) (“Lee”), in further view of N. Bekiaris et al., IEEE International Conference on Interconnect Technology, 1-3 (2017) (“Bekiaris”); and N. Doubina, et al. The effect of thermal annealing on cobalt film properties and grain structure 5 MRS Advances, 1919-1927 (published May 22, 2020) (“Doubina”).
C. Winter et al., US 2015/0004314 (2015) (“Winter”)
Winter discloses a method of reducing a compound having an atom in an oxidized state for forming metal-containing layers (e.g., metal layers) by ALD and by chemical vapor deposition (CVD). Winter at page 6, [0158]. Winter teaches that the method includes a step of reacting a first compound having an atom in an oxidized state with a reducing agent to form a second compound having the atom in a reduced state relative to the first compound. The atom in an oxidized state is selected from the group consisting of Groups 2-12 of the Periodic Table, the lanthanides, As, Sb, Bi, Te, Si, Ge, Sn, and Al. Winter at page 6, [0158]. Winter further teaches that in another refinement of the present embodiment, a method for forming a metal is provided, where the metal is characterized as having metal atoms in the zero-oxidation state. Winter at page 8, [0170].
Winter further teaches that:
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Winter at page 8, [0167]. Cobalt is in group 9 of the periodic table.
With reference to FIG. 2A, Winter teaches forming a layer by an ALD process, where in step a), substrate 10 is contacted with a vapor G1 of a first com pound having an atom in an oxidized state to form a first modified surface 12. Winter at page 8, [0172]. Winter thus teaches that the atom in an oxidized state is selected from the group consisting Groups 2-12 of the Periodic Table, which encompasses instantly claimed cobalt of Group 9. Winter teaches that, in particular, the first compound is as set forth above. Winter at page 8, [0172]. Winter then teaches that in step b) the first modified surface 12 is contacted with a reducing agent G2 for a predetermined pulse time to form layer 14 on the substrate 10. Winter at page 8, [0172]. Winter teaches that the metal can be a transition metal, including cobalt and ruthenium. Winter at page 6, [0158]; Id. at page 7, [0162]. Winter teaches that typically, the first compound having an atom in an oxidized state is contacted with the reducing agent at a temperature from about 50 to 400° C. Winter at page 8, [0171].
Winter teaches that examples of suitable reducing agents include, but are not limited to, hydrazine, hydrazine hydrate, alkyl hydrazines, 1,1-dialkylhydrazines, 1,2-dialkylhydrazines, which meet the instant claim 1 limitation of formula (2). Winter at page 11, [0193].
Winter teaches that the substrates may be metals, such as platinum, palladium, and cobalt. Winter at page 15, [0222]. These substates are “electrically conductive” per instant claim 1.
With respect to independent claim 16, Winter teaches: “Loop L indicates that steps a), P1), b), and P2) are repeated a plurality of times in order to build up a final layer 16 of predetermined thickness monolayer by mono layer”. Winter at page 8, [0172]. Winter therefore teaches the claim 16 limitation of:
Claim 16 . . . wherein steps a) and b) are performed a plurality of times until the metal-containing film is within a predetermined thickness range . . .
In a working example (the “Winter Working Example”), Winter teaches that metallic cobalt films were grown by ALD using a binary process of Co(dadt-Bu) + HCOOH, where each cycle consisted of a 6.0 s pulse of Co(dadt-Bu), a 5.0 s purge, a 0.2 s pulse of HCOOH, and a 5.0 s purge and the temperature of the reaction chamber spanned a range of 140 -240 ˚C. Winter at pages 17-18, [0239].
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The substates used in this working example are Ru, Pt, and Pd, which, per instant claim 1, are electrically conductive. Winter at page 18, [0240].
Here it is clear to one of ordinary skill that the HCOOH (formic acid), which Winter describes as an “activating compound”, is functioning to reduce the initially formed cobalt layer to cobalt metal in a zero-oxidation state. Winter at page 2, col. 2, [0013]; Id. at page 10, [0188]; Id. at page 11, [0192]. As discussed above, Winter teaches that claim 1 compounds of formula (2) are also suitable reducing agents in the process. Winter at page 11, [0193]. Thus, one of ordinary skill would recognize from Winter that, for example, hydrazine is a suitable reducing-agent replacement for formic acid in Winter’s working example.
Differences Between Winter and the Claims 1 and 16
Winter differs from claims 1 and 16 in that Winter does not teach the following claim 1 and 16 step (c):
Claims 1 and 16. . . c) annealing the metal-containing film at a second predetermined temperature that is less than 400 °C in an inert atmosphere for a sufficient time that carbon and nitrogen are not detected by XPS within instrument sensitivity and the metal-containing film includes the metal atom in the zero oxidation state in an amount greater than 98 mole percent . . .
Winter also differs from claim 1 steps (a) and (b), in that while Winter teaches each element of steps (a) and (b), Winter does not put them together in a single embodiment. First, Winter does not teach a species of cobalt compound falling within claim 1 and claim 16 formulae (3.1), (3.2) or (3.3); rather one of ordinary skill must specifically select cobalt as the metal to employ within the genus taught by Winter at page 8, [0167] to arrive at a claimed species of claim 1 formula (3.1) and claim 16 formula (3.3). Still further, to arrive at the claimed process, one of ordinary skill must specifically select a claim 1 and claim 16 compound of formula (2) (from among the listing of potential reducing agents taught by Winter, for example, hydrazine) for use as the reducing agent in Winter’s process.
Claim 16 differs from claim 1 only in that it recites a narrower range of compounds and omits the claim 1 language:
Claim 1 . . . (c) . . . wherein the electrically conductive substrate includes one or more electrically conductive films disposed over a base substrate such that the metal-containing film grows on surfaces of the one or more electrically conductive films.
Claim 16 further differs from claim 1 in that it further requires:
Claim 16 . . . wherein steps a) and b) are performed a plurality of times until the metal-containing film is within a predetermined thickness range . . .
As discussed above, Winter teaches this limitation. Winter at page 8, [0172].
S. Haukka et al., US 2019/0252195 (2019) (“Haukka”)
Haukka teaches methods for depositing a ruthenium - containing film on a substrate by a cyclical deposition process comprising contacting the substrate with a first vapor phase reactant comprising a metalorganic precursor, the metalorganic precursor comprising a metal selected form the group consisting of cobalt, nickel, tungsten, molybdenum, manganese, iron, and combinations thereof. Haukka at page 1, [0008]. With regard to cobalt, Haukka teaches that cobalt (Co) has been proposed as both a barrier layer and a capping layer in back-end-of- line (BEOL) copper interconnection applications. Haukka at page 2, [0030].
Haukka teaches that for example, a thin film of cobalt (Co) may be utilized in BEOL copper interconnects to prevent dewetting of copper from the underlying dielectric material as well as preventing copper diffusion across the boundary between the copper and the dielectric. Haukka at page 2, [0030]. Haukka teaches that therefore, the embodiments of the disclosure may comprise methods to deposit high quality, conformal, cobalt (Co) films. Haukka at page 2, [0030].
Haukka teaches that the metalorganic cobalt precursor may be cobalt betadiketonate compounds, or cobalt amidinate compounds, for example, bis(acetylacetonate)cobalt (II) [CAS Reg. No. 14024-48-7], bis(ethylcyclopentadienyl)cobalt (II), bis(2,2,6,6-tetramethyl-3,5-heptanedionato)cobalt (II) [CAS Reg. No. 13986-53-3], bis(1,4-ditertbutyl-1,3-diazabutadiene)cobalt (II), or bis(N-tertbutyl-N'-ethylpropanimidamidato)cobalt (II). Haukka at page 4, [0047].
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See also, CAS Abstract and Indexed Compounds S. Haukka et al., US 2019/0252195 (2019). These two Haukka compounds meet the chemical structure limitations of instant claim 1 formula (3.1) and formula (3.2) as well as the elected species Co(thd)2.
Haukka further teaches that in some embodiments of the disclosure, the method may comprise an additional process step comprising, contacting the substrate with a third vapor phase reactant comprising a reducing agent and hydrazine (N2H4) is listed by Haukka as an alternative reducing agent. Haukka at page 6, [0070].
N. Bekiaris et al., IEEE International Conference on Interconnect Technology, 1-3 (2017) (“Bekiaris”)
Bekiaris is cited here as motivating one of ordinary skill to perform the following claim 1 and claim 16 step (c) limitation of:
Claims 1 and 16. . . c) annealing the metal-containing film at a second predetermined temperature that is less than 400 °C in an inert atmosphere for a sufficient time that carbon and nitrogen are not detected by XPS within instrument sensitivity and the metal-containing film includes the metal atom in the zero oxidation state in an amount greater than 98 mole percent . . .
Bekiaris teaches that the step of annealing is useful to purify and improve the properties of cobalt films. For example, Bekiaris teaches the following excerpt:
In this paper, plasma enhanced chemical vapor deposition Co at <250°C was used to fill interconnect structures. The as-deposited film contains minor concentrations of C and O impurities from precursor ligand decomposition . The x-ray photoelectron spectroscopy (XPS) depth profile plot in Fig.1 shows a bulk film on a TiN/SiOx substrate that is nearly pure Co after the anneal. The XPS measurement at the dashed line shows C & O in the noise, and supporting secondary-ion mass spectrometry (SIMS) analysis (not shown) confirms C & O <1% each in the bulk. Annealing the as deposited film promotes Co grain growth, seam healing and fill of the structures, as seen in the Fig. 2 cross-section TEM images of CVD Co as deposited and after anneal. TEM images of annealed Co showing good gap fill without voids for a 10nm trench with 20:1 aspect ratio and a dual damascene ULk structure with 17nm via bottom CD are shown in Fig. 3. Top down AFM images in Fig. 4 of 200 Å CVD Co illustrate the grain growth, agglomeration, and surface smoothening of the Co film from the anneal. Supporting XRD data (not shown) prove that the grains grow from ~126 Å as deposited to ~210 Å – or the thickness of the film – after anneal for the films in Fig. 4.
Bekiaris at page 1, cols. 1-2 (emphasis added).
In a working example, Bekiaris teaches plasma enhanced chemical vapor deposition Co at <250°C was used to fill interconnect structures. Bekiaris at page 1, col. 1. The as deposited [Co] film contains minor concentrations of C and O impurities from precursor ligand decomposition. Bekiaris at page 1, col. 1. Bekiaris teaches that depth profile plot in Fig.1 shows a bulk film on a TiN/SiOx substrate that is nearly pure Co after the anneal. Bekiaris at page 1, col. 1. Bekiaris further teaches that annealing the as deposited film promotes Co grain growth, seam healing and fill of the structures. Bekiaris at page 1, col. 1. In the working example, Bekiaris teaches that an annealing temperature of 450 ˚C (per Bekiaris Fig. 6) improves the purity/properties of the Co film. Bekiaris at page 1, col. 2 (“[f]inally, backside SIMS (Fig. 6) of a silicon oxide/ALD TiN/Co stack thermally stressed for 30 min at 450°C shows that 1nm ALD TiN also prevents Co diffusion into the dielectric”) (emphasis added)). Otherwise, Bekiaris does not provide any detailed discussion of the specific or particular ranges of annealing temperatures.
N. Doubina, et al. The effect of thermal annealing on cobalt film properties and grain structure 5 MRS Advances, 1919-1927 (published May 22, 2020) (“Doubina”)
Doubina teaches that that electrodeposited Co film properties such as resistivity, crystallite size, grain phase and morphology, and impurities can be modified by tuning the anneal conditions. Doubina at page 1920, last lines of 3rd paragraph.
In the experimental, Doubina teaches Cobalt film electrodeposition on wafers where the stack Co/TaN/SiO2. Doubina at pages 1920 (last two paragraphs) – page 1921 (first paragraph). In anneal experiments, Doubina teaches placing the cobalt-film coated wafers in an anneal chamber and purging ambient oxygen with a H2/He gas mixture. Doubina at page 1921 (2nd paragraph). Following oxygen purge, the wafter was heated (annealed) on a pedestal for set time under 26T H2 and cooled. Doubina at page 1921 (2nd paragraph).
Doubina teaches that, most significantly, it was found that when anneal is completed at temperatures between 300- 350°C, there is a phase transition of mixed phase Co grains to primary hcp phase and a large grain size increase accompanied by a significant decrease in resistivity approaching the values of bulk Cobalt. Doubina at page 1926. Doubina teaches that grain size analysis on the pattern structures revealed a 10X magnitude crystallite size increase within the trenches at 350°C anneal condition. Id. The understanding and control of the metal grain size dependence on various anneal parameters is critical for developing and fabricating high performance devices for the advanced nodes. Id.
S. Lee et al., US 2021/0032279 (2021) (“Lee”)
Lee is cited here for the that annealing is useful for removing impurities, such as carbon and oxygen, from cobalt films formed by vapor deposition processes.
Lee teaches a method of selectively forming a cobalt metal layer, the method including supplying a cobalt compound represented by Chemical Formula (1) onto a substrate that includes a wiring line of a late transition metal and an isolation film adjacent thereto, and supplying a reducing gas to selectively form a cobalt metal layer on the wiring line. Lee at page 1, [0004]. In film forming working Examples 1-12, Lee teaches forming a cobalt metal layer on copper wiring, using a chemical vapor deposition (CVD) process, with hydrogen as the reducing gas and using the following three cobalt compounds of Chemical Formula (1). Lee at page 10 (data in Table 1 at page 11).
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The above structures were indexed from Lee by CAS and their chemical structures were drawn as above by CAS. See attached reference CAS Abstract and Indexed Compounds, S. Lee et al., US 2021/0032279 (2021). Lee however, draws their structures in a different resonance form, where two of the keto-cobalt bonds are omitted. See Lee at page 9. However, the structures drawn by Lee and those drawn by CAS are the same cobalt complexes; they are just drawn as different resonance structures.
Significantly, Lee compounds 1, 2 and 3 all fall within the scope claim 1 formula (3.2).
Also note that while Lee’s working Examples 1-12 all employ hydrogen as the reducing gas, Lee discloses the following:
The reducing gas may include, for example, at least one selected from the group consisting of H2, N2, NH3, N2H4, N(SiH3)3, N(CH3)H2, N(C2H5)H2, N(CH3)2H, N(C2H5)2H, N(CH3)3, N(C2H5)3, (SiMe3)2NH, (CH3)HN-NH2, (CH3)2N-NH2, phenylhydrazine, pyrazoline, and radicals thereof.
Lee at page 6, [0090].
With respect to annealing the so formed cobalt films, Lee teaches that:
[0120] The cobalt metal layer formed by the method according to an example embodiment may be formed without post-treatment such as annealing or plasma treatment. Thus, due to an extremely high amount of cobalt in the formed cobalt metal layer, annealing or plasma treatment for removing impurities such as carbon may be avoided.
[0216] As shown in Table 2, it was confirmed that, when the cobalt metal layer was formed by using the cobalt compound according to an example embodiment, the cobalt metal layer could be formed at a high purity greater than 97 atom %. Further, it was confirmed that, because impurities such as carbon or oxygen were present in an extremely low amount, post-treatment such as annealing or plasma treatment was not needed.
Lee at pages 7-8, [0120]; Id. at page 12, [0216]. Although Lee teaches that an annealing step was not required for his specific compounds, Lee teaches one of ordinary skill that, generally, annealing is useful for removing impurities, such as carbon and oxygen, from cobalt films formed by vapor deposition processes.
Obviousness Rationale
Claims 1-3, 5-6, 9, 12-14, 16-18, and 20-23 are obvious, because one of ordinary skill is motivated to use either of Haukka compounds CAS Reg. Nos. 13986-53-3 or 14024-48-7 (which meet instantly claimed formulae (3.1) and (3.3)):
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in the Winter Working Example ALD process (Winter at pages 17-18, [0239]) in place of Winter’s Co(dadt-Bu or in the Winter ALD process of Fig. 2A (Winter at page 8, [0172]) using a compound of instantly claimed formula 2 as the reducing agent,2 for example hydrazine, (in place of the formic acid used in the Winter working examples), a plurality of times in order to build up a cobalt metal film “in a zero oxidation state in an amount greater than 80 mole percent” on a ruthenium substrate (as taught in the Winter working example) or on copper wire (as taught by Lee), which are per claim 1 “an electrically conductive substrate”.
One of ordinary skill is so motivated because Winter specifically teaches that suitable metal film forming precursors are selected from the genus of:
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and Haukka teaches that CAS Reg. Nos. 13986-53-3 or 14024-48-7 (which both fall within the Winter [0167] genus) are both suitable for forming metal cobalt films. Haukka at page 4, [0047].
With respect to the claim 1 and claim 16, step (b) limitation of “in a zero-oxidation state in an amount greater than 80 mole percent”, one of ordinary skill is motivated to fully reduce the initially formed cobalt film with, for example hydrazine, such that the layer formed is fully (100 mole%) metallic cobalt (zero oxidation state). One of ordinary skill is so motivated in view of Haukka’s teaching that cobalt (Co) has been proposed as both a barrier layer and a capping layer in back-end-of- line (BEOL) copper interconnection applications. Haukka at page 2, [0030]. Such use necessarily requires fully reduced, metallic cobalt (zero-oxidation) state as evidenced by L. Kalutarage et al., 52 Inorganic Chemistry, 5385-5394 (2013) (page 5385, at col.1 “[m]etallic thin films of the first-row transition metal elements copper, nickel, cobalt, iron, manganese, and chromium have many important current and future applications. These include copper interconnects in microelectronics devices, chromium, cobalt, and other metal seed layers for copper metallization, cobalt capping layers for copper lines”); see also, K. Vayrynen et al., 30 Chemistry of Materials, 3499-3507 (2018) and T. Elko-Hanse et al., 80 ECS Transaction, 29-37 (2017).
One of ordinary skill practicing Winter and Haukka as above, is further motivated by Bekiaris and Doubina to perform the following claim 1 and claim 16 annealing step (c):
Claims 1 . . . c) annealing the metal-containing film at a second predetermined temperature that is less than 400 °C in an inert atmosphere for a sufficient time that carbon and nitrogen are not detected by XPS within instrument sensitivity and the metal-containing film includes the metal atom in the zero oxidation state in an amount greater than 98 mole percent
wherein the electrically conductive substrate includes one or more electrically conductive films disposed over a base substrate such that the metal-containing film grows on surfaces of the one or more electrically conductive films.
Claims 16 . . . c) annealing the metal-containing film at a second predetermined temperature that is less than 400 °C in an inert atmosphere for a sufficient time that carbon and nitrogen are not detected by XPS within instrument sensitivity and the metal-containing film includes the metal atom in the zero oxidation state in an amount greater than 98 mole percent.
because Bekiaris teaches that the as deposited [Co] film contains minor concentrations of C and O impurities, which are removed by the step of annealing and that annealing promotes Co grain growth, seam healing and fill of the structures. Bekiaris at page 1, col. 1. Further, Lee teaches one of ordinary skill that annealing is useful for removing impurities, such as carbon and oxygen, from cobalt films formed by vapor deposition processes. Lee at pages 7-8, [0120]; Id. at page 12, [0216].
The above claim 1 and 16 annealing temperature and time limitations are obvious in view of Bekiaris and Doubina because, although Bekiaris teaches a single annealing temperature of 450 ˚C and Bekiaris does not provide any detailed discussion of annealing temperatures or times, one of skill is motivated to optimize within the claimed time and temperature ranges of “annealing the metal-containing film at a second predetermined temperature that is less than 400 °C3 in an inert atmosphere for a sufficient time that carbon and nitrogen are not detected by XPS within instrument sensitivity” (rather than 450 °C as taught by Bekiaris’s example).4 MPEP §2144.05 (II)(A). For example, Doubina teaches that, with electroplated cobalt films anneal is completed at temperatures between 300- 350°C. Doubina at page 1926. And Doubina teaches that grain size analysis on the pattern structures revealed a 10X magnitude crystallite size increase within the trenches at 350°C anneal condition. Id. Doubina teaches that the understanding and control of the metal grain size dependence on various anneal parameters is critical for developing and fabricating high performance devices for the advanced nodes. Id.
One of ordinary skill is motivated to continue the anneal for as long as it takes to reduce carbon impurities to about 0%, which would necessarily result in carbon being undetectable “by XPS within instrument sensitivity” (as per claims 1 and 16). In this regard, Lee teaches 0% carbon impurities. Lee at page 6, [0096]. Regarding nitrogen impurities, one of ordinary skill employing Haukka compound (i.e., CAS Reg. Nos. 13986-53-3 or 14024-48-7), as proposed above, necessarily achieves “nitrogen are not detected by XPS within instrument sensitivity” because no nitrogen is present in these compounds to begin with.
Finally, the claim 1 and 16 term “annealing . . . in an inert atmosphere” is met by the above § 103 rationale for the following reasons. As discussed in Claim Interpretation above, in the absence of a speciation definition, the term “inert atmosphere”, in the context of claim 1 and claim 16 annealing step (c), is broadly and reasonably interpreted, consistently with the specification, as any atmosphere in which the elemental Co0 is unreactive at the particular annealing temperature. MPEP § 2111; specification at page 22, [0100]. Here, one of ordinary skill is motivated to ensure that the annealing atmosphere is inert to elemental Co0 because this is the very product desired. For example, one of ordinary skill could employ the hydrogen annealing atmosphere as taught by Doubina. Doubina at page 1921 (2nd paragraph). Or a nitrogen or argon atmosphere. In sum, “annealing . . . in an inert atmosphere” is an obvious limitation.
The cited art, combined as proposed above, therefore clearly meets each and every limitation of claims 1, 5, 6, 9, 14, 16, and 20.
The limitations of claims 2 and 17 (i.e., “wherein the metal-containing film includes [metastable] metal nitrides in an amount less than 20 mole percent”) are met for the following reasons. The above proposed § 103 rationale employs cobalt precursors containing no nitrogen to begin with, thus metal nitrides will inherently not be present at all. Once a reference teaching a product appearing to be substantially identical is made the basis of a rejection, and the examiner presents evidence or reasoning to show inherency, the burden of production shifts to the applicant. MPEP § 2112(V) (citing In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433-34 (CCPA 1977). Here the specification mentions metal nitrides only once without explanation:
[0082] . . . In a refinement, the metal-containing film includes metastable metal nitrides in an amount less than 20 mole percent. In a further refinement, the metal-containing film includes the metal atom in a zero oxidation state in an amount greater than 90 mole percent and metastable metal nitrides in an amount less than 10 mole percent.
The specification provides no other discussion of metal nitrides, such as how they are formed. The § 103 proposed process is nearly identical to the specification working example. Specification at page 23, [0103]. That is Co(thd)2 (of the specification working example) is Haukka compound is CAS Reg. No. 13986-53-3.
The limitations of claims 3 and 18 are met because one of ordinary skill is motivated to optimize the temperature and pressure ranges of the proposed process to within the claim 3 ranges. Regarding temperature, Winter teaches that during film formation, the substrate will be at a temperature suitable to the properties of the chemical precursor(s) and film to be formed and Winter teaches a range of 0 to 1000 ˚C. Winter at page 9, [0181]. Regarding pressure, Winter teaches that the pressure during film formation is set at a value suitable to the properties of the chemical precursors and film to be formed and Winter teaches a pressure range of from about 10 Torr to about 760 Torr. Winter at page 10, [0182]. The claimed ranges fall within the disclosed ranges. In the case where the claimed ranges overlap or lie inside ranges disclosed by the prior art a prima facie case of obviousness exists. MPEP § 2144.05(I).
The claims 12 electrical resistivity limitation is necessarily met by the § 103 proposed process on a ruthenium substrate because it is nearly identical to the only specification working examples also performed on a ruthenium substrate. Specification at page 21, [0096]. That is Co(thd)2 (of the specification working example) is Haukka compound is CAS Reg. No. 13986-53-3 grown on ruthenium substrate. Once a reference teaching a product appearing to be substantially identical is made the basis of a rejection, and the examiner presents evidence or reasoning to show inherency, the burden of production shifts to the applicant. MPEP § 2112(V) (citing In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433-34 (CCPA 1977).
The limitations of claim 13 are met because Haukka compound is CAS Reg. No. 13986-53-3 grown on ruthenium substrate, which is a metal.
The limitations of claim 14 are met because the above-cited Winter Working Example employs ruthenium as a substrate and Lee employs copper as a substrate.
The limitations of claims 21-23 are necessarily met by practice of the proposed process a plurality of times in order to build up a cobalt metal film, since each successive Co film is formed on the preceding cobalt film layer.
Winter teaches the claimed atomic layer deposition (ALD) process. Winter at page 1, [0005].
These steps of contacting the substrate with the first chemical composition, purging, contacting the substrate with the second gaseous chemical composition, and purging are usually repeated a plurality of times until a film of desired thickness is coated onto the substrate.
Winter at page 1, [0005].
Applicant’s Argument
Applicant argues that Winter and Haukka do not teach, per claim 1, annealing, at less 400 °C, in an inert atmosphere “for a sufficient time that carbon and nitrogen are not detected by XPS”:
Claims 1 and 16. . . c) annealing the metal-containing film at a second predetermined temperature that is less than 400 °C in an inert atmosphere for a sufficient time that carbon and nitrogen are not detected by XPS within instrument sensitivity and the metal-containing film includes the metal atom in the zero oxidation state in an amount greater than 98 mole percent . . .
Applicant argues that Bekiaris reports plasma-enhanced CVD of cobalt, uses a uses a 450 °C anneal (outside of the claimed range), and while reports that carbon and oxygen drop to the noise after anneal, Bekiaris paper does not discuss nitrogen. Applicant argues hat one of ordinary skill would not have expected the claimed end point of “carbon and nitrogen are not detected by XPS within instrument sensitivity”, whereas Applicant's data show carbon and nitrogen at zero by XPS after a controlled in-chamber anneal. Applicant argues that routing optimization does not fit the amended claims and the cited art does not teach nitrogen removal at any temperature under inert conditions.
This argument is not persuasive because one of skill is motivated to optimize within the claimed time and temperature ranges of “annealing the metal-containing film at a second predetermined temperature that is less than 400 °C in an inert atmosphere for a sufficient time that carbon and nitrogen are not detected by XPS within instrument sensitivity” (rather than 450 °C as taught by Bekiaris’s example). MPEP §2144.05 (II)(A).
Differences in temperature will generally not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such temperature is critical. MPEP §2144.05 (II)(A). Where 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. MPEP §2144.05 (II)(A) (citing In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). Here the specification provides no teaching that the annealing temperature or time is critical. See specification at page 15, [0083].
For example, Doubina teaches that, with electroplated cobalt films anneal is completed at temperatures between 300- 350°C. Doubina at page 1926. And Doubina teaches that grain size analysis on the pattern structures revealed a 10X magnitude crystallite size increase within the trenches at 350°C anneal condition. Id. Doubina teaches that the understanding and control of the metal grain size dependence on various anneal parameters is critical for developing and fabricating high performance devices for the advanced nodes. Id.
One of ordinary skill is motivated to continue the anneal for as long as it takes to reduce carbon impurities to about 0%, which would necessarily result in carbon being undetectable “by XPS within instrument sensitivity” (as per claims 1 and 16). In this regard, Lee teaches 0% carbon impurities. Lee at page 6, [0096]. Regarding nitrogen impurities, one of ordinary skill employing Haukka compound (i.e., CAS Reg. Nos. 13986-53-3 or 14024-48-7), as proposed above, necessarily achieves “nitrogen are not detected by XPS within instrument sensitivity” because no nitrogen is present in these compounds to begin with.
The claim 1 and 16 term “annealing . . . in an inert atmosphere” is met by the above § 103 rationale for the following reasons. Per above, the term “inert atmosphere” is broadly and reasonably interpreted, consistently with the specification, as any atmosphere in which the elemental Co0 is unreactive at the particular annealing temperature. MPEP § 2111; specification at page 22, [0100]. Here, one of ordinary skill is motivated to ensure that the annealing atmosphere is inert to elemental Co0 because this is the very product desired. For example, one of ordinary skill could employ the hydrogen annealing atmosphere as taught by Doubina. Doubina at page 1921 (2nd paragraph). Or a nitrogen or argon atmosphere. In sum, “annealing . . . in an inert atmosphere” is an obvious limitation.
Applicant argues that new claim 23 is patentable over the cited references because none of them discloses or suggests an ALD process in which repeating the precursor and reducing-agent pulses produces a linear increase in cobalt concentration in the deposited film with increasing cycle count. Applicant cites the specification results based on X-ray fluorescence data obtained at 285 °C using Co(thd)2 and 1,1-dimethylhydrazine, that cobalt concentration increases linearly as the number of ALD cycles increases. Applicant argues that this experiment shows that the growth rate versus cycles is not linear, demonstrating that the observed linearity pertains to cobalt composition rather than to thickness accumulation, and that the process therefore produces a controlled stoichiometric progression unique to the disclosed chemistry. In contrast, Winter describes repeating ALD cycles to build a metal layer "monolayer by monolayer" but never measures cobalt concentration or identifies any linear compositional trend in the resulting film. Haukka discloses possible cobalt [Symbol font/0x62]-diketonate precursors yet provides no data or teaching on cobalt concentration behavior across cycles. Bekiaris relates to plasma-enhanced CVD rather than true ALD and does not address cycle-by- cycle composition.
This argument is not persuasive for the following reasons. Applicant appears to be referencing the following specification portion which reports the results of atomic layer deposition of Co(thd)2 and 1,1-dimethylhydrazine as the reducing gas (as proposed above in the § 103 rationale):
[0098] Figure 14 provides plot of the growth rate versus number of cycles for a cobalt metal film deposited at 285 °C from Co(thd)2. Growth behavior of the film was also analyzed with increasing numbers of ALD cycles. A linear trend was not observed. X-ray fluorescence analysis of the films shows a linear increase in the concentration of cobalt with increasing cycles. This indicates the density of the film increases with the increasing number of cycles, consistent with annealing of the film during longer deposition times.
Specification at page 22, [0098]; see page 23, [0103] for ALD experimental conditions. Fig. 14 shows a linear increase in the concentration of cobalt with increasing cycles
The specification teaches that atomic layer deposition experiments were performed on a Picosun R200 ALD reactor operating at 6-10 Torr from 200-300 °C, where ultrahigh purity N2 (99.999%, Airgas) was used as the carrier and purge gas; cobalt metal was deposited using Co(thd)2 and 1,1-dimethyl hydrazine (DMH) from 265- 300 °C using the following pulse sequence: Co(thd)2 (3.0 s), N2 purge (10 s), DMH (0.2 s), N2 purge (10 s). Co(thd)2 was delivered to the reaction chamber at 130 °C and DMH was delivered at ambient temperature (~22 °C).
Winter teaches that the ALD pressure conditions are preferably from about 1 to 20 millitorr. Winter at page 19, [0182]. Winter teaches that, preferably, the pulse and purge times are each independently from about 0.1 to about 10 seconds. Winter at page 10, [0183]. Winter teaches that, preferably, the substrate has a temperature from about 200 to 300° C. Winter at page 12, [0201]. Thus, Winter teaches the same ALD conditions employed by the specification example. As such, practice of Winter, as proposed in the § 103 rationale would give the same linear increase in the concentration of cobalt with increasing cycles; that is the same cobalt film claimed. Where the claimed and prior art products are identical or substantially identical in composition to a claimed composition, a prima facie case of either anticipation or obviousness has been established subject to Applicant’s rebuttal. MPEP § 2112.01(I) (citing In re Ludtke, 441 F.2d 660, 169 USPQ 563 (CCPA 1971) (holding that a prior art structure anticipated a claimed structure even though a claimed functional recitation was not specifically taught in the prior art reference because applicant had failed to show that the prior art did not possess the functional characteristics of the claims)); see also, MPEP § 2112(V) (citing In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433-34 (CCPA 1977). The limitation of claim 23 are therefore met by the proposed § 103 rationale.
Conclusion
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ALEXANDER R. PAGANO
Examiner
Art Unit 1692
/ALEXANDER R PAGANO/Primary Examiner, Art Unit 1692
1 A claim may lack written description support the claim defines the invention in functional language specifying a desired result but the disclosure fails to sufficiently identify how the function is performed or the result is achieved. MPEP § 2163.03 (V) (citing Ariad Pharms., Inc. v. Eli Lilly & Co., 598 F.3d 1336, 1349-50 (Fed. Cir. 2010) ("[e]ven if a claim is supported by the specification, the language of the specification, to the extent possible, must describe the claimed invention so that one skilled in the art can recognize what is claimed”).
2 One of ordinary skill is motivated to select the claim 1 and claim 16 formula 2 reducing agent as any of hydrazine, hydrazine hydrate, alkyl hydrazines, 1,1-dialkylhydrazines, 1,2-dialkylhydrazines (for example hydrazine as taught by the instant specification at page 14, [0080]), because each of Winter, Haukka, and Lee teach these (including hydrazine) are suitable reducing gases to convert the organocobalt precursor to elemental Co0. Winter at page 11, [0193]; Haukka at page 6, [0070]; Lee at page 6, [0090].
3 The specification working examples teach an annealing temperature of 400 °C. The instantly claimed and exemplified temperature of 400 ˚C is relatively close to Bekiaris’s annealing temperature of 450 °C. A prima facie case of obviousness exists where the claimed ranges or amounts do not overlap with the prior art but are merely close. MPEP § 2144.05(I).
4 Differences in temperature will generally not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such temperature is critical. MPEP §2144.05 (II)(A). Where 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. MPEP §2144.05 (II)(A) (citing In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). Here the specification provides no teaching that the annealing temperature or time is critical. See specification at page 15, [0083].