DETAILED ACTION
Claim Interpretation
It is noted that for the purpose of examination, the examiner treats transitional phase “has” in claims 2, 3 and 4, line 2, as open claim language. According to Specification, last paragraph on page 11, examples of the quaternary phosphonium salts include tetraphenylphosphonium fluoride, tetrabutylphosphonium fluoride, methyltriphenylphosphonium fluoride. Thus, based on aforementioned examples, the quaternary phosphonium salts include multiple substituents. See MPEP §2111.03(IV).
Claim Rejections - 35 USC § 102
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claims 1-3, 6-8, 11 and 14-15 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Shimada et al. (JP 2013120885 A) with reference to the provided machine translation, hereinafter referred to as SHIMADA.
Regarding claim 1, SHIMADA teaches a polishing composition (paragraph [2]: a polishing liquid for CMP) comprising:
abrasive grains; and
a quaternary ammonium salt (paragraph [23]: polishing liquid using silica particles as abrasive grains and comprising a quaternary phosphonium salt),
wherein a pH is less than 7.0 (paragraph [31]: the pH of the polishing slurry for CMP is preferably in the acidic region; the acidic region is defined as less than pH 6.5), and
a zeta potential of the abrasive grains in the polishing composition is -10 mV or less (paragraph [29]: a silica particle having a zeta potential of -10 mV or less).
SHIMADA teaches ranges which are within and anticipate the claimed ranges.
Regarding claim 2, SHIMADA teaches the polishing composition according to claim 1, wherein the quaternary phosphonium salt has at least one of a substituted or unsubstituted aryl group bonded to a phosphorus atom and a substituted or unsubstituted alkyl group bonded to a phosphorus atom (see general formula (1) below and paragraph [48]: R1 to R3 in the general formula (1) are each an alkyl group having a benzene ring, preferably a benzyl group or a derivative of a phenyl group, or a linear alkyl having 4 or less carbon atoms, R4 represents a linear alkyl group or a branched alkyl group having 4 or less carbon atoms; the anion of X − in the general formula (1) is not particularly limited, but halogen ions (for example, F −, Cl −, Br −, I −)).
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General Formula (1)
Regarding claim 3, SHIMADA teaches the polishing composition according to claim 1, wherein the quaternary phosphonium salt has a substituted or unsubstituted alkyl group bonded to a phosphorus atom (paragraph [48]: R1 to R3 in the general formula (1) are each an alkyl group having a benzene ring, preferably a benzyl group or a derivative of a phenyl group, or a linear alkyl having 4 or less carbon atoms, R4 represents a linear alkyl group).
Regarding claim 6, SHIMADA teaches the polishing composition according to claim 1, wherein the abrasive grains are anion-modified colloidal silica (paragraphs [50]: abrasive grains having a negative charge; [51]: abrasive particles modified with sulfonic acid; and [52]: colloidal silica is used as particles used for the CMP polishing slurry).
Regarding claim 7, SHIMADA teaches the polishing composition according to claim 1, further comprising a pH adjusting agent (paragraphs [69]: the polishing liquid for CMP contains a metal oxide dissolver; and [70]: such metal oxide solubilizers are used for the purpose of pH adjustment).
Regarding claim 8, SHIMADA teaches the polishing composition according to claim 1, further comprising a dispersing medium (paragraph [63]: the medium for the polishing liquid for CMP is not particularly limited as long as it is a liquid in which the silica particles can be dispersed).
Regarding claim 11, SHIMADA teaches the polishing composition according to claim 1, which is used for polishing an object to be polished containing a Low-k material and silicon nitride. It is noted that claim 1 is drawn to a polishing composition. The limitation “is used for polishing an object to be polished containing a Low-k material and silicon nitride” recited in claim 11 is being treated as a statement of intended use, and thus is not considered as further limiting structurally the polishing composition according to claim 1. However, SHIMADA discloses an object to be polished comprising interlayer insulating film including silicon-based film (e.g., silicon nitride) (paragraphs [98-99]), and organic polymer film, for example low-k film (paragraph [101]).
Regarding claim 14, SHIMADA teaches a polishing method comprising polishing an object to be polished containing a low-k material and silicon nitride by using the polishing composition according to claim 1 (paragraphs [97]: a polishing method; a second polishing step of polishing at least the barrier film and the silicon dioxide film on the convex portion while supplying a liquid to expose the low-k film of the convex portion; and [99]: as the silicon-based film, for example, silicon dioxide, fluorosilicate glass, organosilicate glass obtained using trimethylsilane or dimethoxydimethylsilane as a starting material, silica-based film such as silicon oxynitride, hydrogenated silsesquioxane, silicon carbide, silicon nitride, and the like).
Regarding claim 15, SHIMADA teaches a method for producing a semiconductor substrate (paragraph [39]: the present invention also relates to a semiconductor substrate manufactured using the above-described polishing method), comprising polishing a semiconductor substrate containing a Low-k material and silicon nitride by the polishing method according to claim 14 (see rejection of claim 14 above).
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 4-5, 10 and 13 are rejected under 35 U.S.C. 103 as being unpatentable over SHIMADA.
Regarding claim 4, SHIMADA teaches the polishing composition according to claim 1, wherein the quaternary phosphonium salt has a tetraalkylphosphonium cation, and a maximum number of carbon atoms of an alkyl group that the teraalkylphosphonium cation has is 2 or more and 10 or less (paragraph [48]: R1 to R3 in the general formula (1) are each an alkyl group having a benzene ring, preferably a benzyl group or a derivative of a phenyl group, or a linear alkyl having 4 or less carbon atoms, R4 represents a linear alkyl group or a branched alkyl group having 4 or less carbon atoms). SHIMADA teaches a range of less than 4, which overlaps and renders obvious the claimed range. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. In re Wertheim. See MPEP §2144.05(I).
Regarding claim 5, SHIMADA teaches the polishing composition according to claim 4, wherein the quaternary phosphonium salt is at least one of tetra-n-butyl phosphonium hydroxide and tetraethylphosphonium bromide (paragraph [48]: R1 to R3 in the general formula (1) are each a linear alkyl having 4 or less carbon atoms, R4 represents a linear alkyl group or a branched alkyl group having 4 or less carbon atoms; the anion of X − in the general formula (1) is not particularly limited, but halogen ions (for example, F −, Cl −, Br −, I −), hydroxide ion).
Regarding claim 10, SHIMADA teaches the polishing composition according to claim 1, wherein the zeta potential of the abrasive grains in the polishing composition is -40 mV or more and -15 mV or less (paragraph [29]: a silica particle having a zeta potential of -10 mV or less). SHIMADA teaches a range of less than -10 mV, which overlaps and renders obvious the claimed range.
Regarding claim 13, SHIMADA teaches the polishing composition according to claim 11. While SHIMADA is silent with respect to a ratio of a polishing removal rate of the Low-k material to a polishing removal rate of the silicon nitride (Low-k material/silicon nitride) being 1.0 or more and 2.0 or less, SHIMADA teaches all limitations of claim 1, as set forth. Accordingly, one of ordinary skill in the art would anticipate the polishing composition of SHIMADA to necessarily comprise the claimed functions such as a ratio of a polishing removal rate of the Low-k material to a polishing removal rate of the silicon nitride (Low-k material/silicon nitride) being 1.0 or more and 2.0 or less. See MPEP §2112.01(I): “where the claimed and prior art products are identical or substantially identical in structure or composition, or are produced by identical or substantially identical processes, a prima facie case of either anticipation or obviousness has been established. In re Best”.
Claims 1, 9 and 12 are rejected under 35 U.S.C. 103 as being unpatentable over SHIMADA, in view of Mae et al. (US 20210079264 A1), hereinafter referred to as MAE.
Regarding claim 1, MAE teaches a polishing composition (see MAE at paragraph [0002]: a polishing composition) comprising:
abrasive grains (see MAE at paragraph [0030]: a colloidal silica having an organic acid immobilized on the surface),
wherein a pH is less than 7.0 (see MAE at paragraph [0057]: the pH of the polishing composition is less than 4.0), and
a zeta potential of the abrasive grains in the polishing composition is -10 mV or less (see MAE at paragraph [0030]: the zeta potential of the colloidal silica in the polishing composition in the range of −60 mV or higher and −35 mV or lower).
But MAE fails to explicitly teach wherein the composition comprises a quaternary ammonium salt.
However, SHIMADA discloses a polishing composition comprising anionic silica abrasives having a zeta potential of less than -10 mV, and having a pH of less than 6.5 (see SHIMADA at paragraphs [29] and [31]). Similarly to MAE describing that an object of the disclosed invention is to provide a polishing composition that can polish a film having a low relative dielectric constant/low-k material , such as SiOC at a high polishing speed (see MAE at paragraphs [0004] and [0006]), SHIMADA discloses that the object of the disclosed invention is to provide a polishing solution and a polishing method capable of polishing and achieving a high polishing rate for a low-k film (see SHIMADA at paragraph [20]). SHIMADA teaches that the invention is focused on the hydrophobicity of the low-k film, and that it was possible to make the abrasive grains approach the low-k film through the substance having an affinity for this; in the polishing slurry for CMP the quaternary phosphonium salt compound represented by the general formula (1) plays a role like a surfactant; hydrophobic substituents present in the cationic part, such as methyl groups, are adsorbed in large amounts on highly hydrophobic low-k membranes; as a result, a large number of positive charges exist on the low-k film, electrostatic interaction occurs with the abrasive grains of the negative charge, and the abrasive grains on the low-k film are attracted to each other (see SHIMADA at paragraph [46]). SHIMADA also teaches that a high polishing rate can be achieved by the approach of the low-k film and the negatively charged abrasive grains (see SHIMADA at paragraph [46]).
Both, MAE and SHIMADA disclose polishing composition comprising similar constituents capable of polishing and achieving a high polishing rate for a low-k film. According to MPEP § 2144.06(I), "It is prima facie obvious to combine two compositions each of which is taught by the prior art to be useful for the same purpose, in order to form a third composition to be used for the very same purpose.... [T]he idea of combining them flows logically from their having been individually taught in the prior art." In re Kerkhoven, 626 F.2d 846, 850, 205 USPQ 1069, 1072 (CCPA 1980).
Thus, one of ordinary skill in the art would have recognized the potential benefit of improving the polishing composition of MAE by adding the quaternary phosphonium salt as disclosed by SHIMADA since SHIMADA explicitly teaches that the quaternary phosphonium salt compounds are adsorbed in large amounts on highly hydrophobic low-k membranes, resulting in a large number of positive charges existing on the low-k film, leading to electrostatic interaction with the abrasive grains of the negative charge, thus, a high polishing rate can be achieved (see SHIMADA at paragraph [46]).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the polishing composition of MAE by adding the quaternary phosphonium salt disclosed by SHIMADA in order to achieve a high polishing rate of a low-k film.
Regarding claim 9, MAE as modified by SHIMADA teaches the polishing composition according to claim 1, wherein a concentration of an oxidizing agent in the polishing composition is less than 100 ppm by mass (see MAE at paragraph [0080]: the lower limit of the content of the oxidizing agent in the polishing composition is preferably 0.001% by mass or more, and more preferably 0.01% by mass or more). MAE teaches 10 to 100 ppm, which overlaps and renders obvious the claimed range.
Regarding claim 12, MAE as modified by SHIMADA teaches the polishing composition according to claim 11, wherein the Low-k material is SiOC (see MAE at paragraph [0004]: an insulating film having a low relative dielectric constant, such as SiOC).
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure:
Arakawa et al. (US 20210062041 A1) discloses a polishing liquid containing abrasive grains, a quaternary phosphonium cation, and a liquid medium (Abstract).
Kamimura et al. (US 8932479 B2) discloses a polishing liquid which is used for chemical mechanical polishing of a body to be polished having a layer containing polysilicon or a modified polysilicon, and using which the polishing rate of a layer containing a silicon-based material other than polysilicon is high and polishing of the layer containing polysilicon can be selectively suppressed; the polishing liquid includes components (A), (B), and (C), has a pH of from 1.5 to 7.0, and is capable of selectively polishing a second layer with respect to a first layer: (A) colloidal silica particles having a negative .zeta. potential; (B) phosphoric acid or an organic phosphonic acid compound (Abstract).
Any inquiry concerning this communication or earlier communications from the examiner should be directed to ANASTASIA KUVAYSKAYA whose telephone number is (703)756-5437. The examiner can normally be reached Monday-Thursday 7:00am-5:00pm.
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/A.A.K./Examiner, Art Unit 1731
/ANTHONY J GREEN/Primary Examiner, Art Unit 1731
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