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 .
Disposition of Claims
Claims 1, 4 and 5 are pending. Claims 2 and 3 have been cancelled by a previous amendment. No additional amendments have been made since the mailing date of the most recent office action, the Non-Final Rejection mailed 22 May 2025.
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
Determining the scope and contents of the prior art.
Ascertaining the differences between the prior art and the claims at issue.
Resolving the level of ordinary skill in the pertinent art.
Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1, 4 and 5 are rejected under 35 U.S.C. 103 as being unpatentable over Okimoto et al. (WO-2009119178-A1, hereinafter “Okimoto”) and Adil et al. (PLoS ONE 2020, 15(7), e0236837, hereinafter “Adil”). Evidentiary support of the increased wettability of polyoxyethylene with a molecular weight of 20,000 amu is provided by Zhang et al. (Applied Surface Science 2012, 258, 8814–8818, hereinafter “Zhang”) and is applied to claim 1 and, by extension, claims 4 and 5.
Regarding claim 1, Okimoto teaches a surface-modified colloidal silica (see paragraph 0001), comprising colloidal silica and a surface-modifying group for modifying the surface of the colloidal silica (see paragraph 0009), which has a polyoxyalkylene chain wherein the polyoxyalkylene is polyoxyethylene (see paragraph 0010 teaching the surface-modifying groups as comprising ethyleneoxide [EO in the given structures; synonymous with polyoxyethylene], assuming n = 0 for propyleneoxide [PO in the given structures]).
Okimoto fails to explicitly teach the limitation wherein the polyoxyethylene has a molecular weight of 20,000 or more (see paragraph 0010; if m and p are taken to be their maximum theoretical values of 170, and if n is taken to be 0, then the maximum theoretical molecular weight of the chain would be 14,977 amu). Adil teaches surface-modified silica nanoparticles (see generally abstract) wherein the surface-modifying group is polyethyleneglycol with a molecular weight of 20,000 amu (see page 4, section “Silica/PEG-20000 NPs”; polyethyleneglycol [PEG] is synonymous with polyoxyethylene). Furthermore, Adil teaches the PEG-20000-modified silica nanoparticles as having increased wettability over unmodified nanoparticles (see page 19, Table 7 and the paragraph immediately below it; the glass surface, after being treated with surface-modified silica nanoparticles, is taught to shift from oil-wet to water-wet, indicating an increase in wettability). These findings are corroborated by Zhang, who teaches PEG-20000-modified copper alloys (see page 8817, Figure 5, sample D, which represents the contact angle for an alloy modified with polyoxyethylene having a molecular weight of 20,000 amu; as can be seen in the figure, increasing molecular weight of the PEG corresponds to a decreasing water contact angle, which indicates an increase in wettability).
As has been shown, Okimoto and Adil both teach a surface-modified colloidal silica wherein the surface-modifying group is polyoxyethylene (PEG). While Okimoto fails to teach the PEG as having the claimed molecular weight, Adil does teach PEG with a weight average molecular weight of 20,000 as claimed. Applicants note in their specification that the composition of Okimoto is limited by poor wettability and stability over time, which the applicants claim to overcome using higher molecular weight polymers. It is well-understood in the art that the wettability of a surface is directly correlated to the surface’s hydrophilicity; as the surface becomes more hydrophilic, it simultaneously becomes more wettable. For a CMP slurry using surface-modified silica nanoparticles, higher molecular-weight polyoxyethylene would have more hydrophilic ether linkages. This means the silica particles would have better dispersion in the aqueous slurry (see Okimoto, paragraph 0018 teaching hydrophobicity of the surface-modifying agent as leading to poor dispersion of the CMP slurry and dishing in the polished wafer). Faced with the insufficient hydrophilicity of Okimoto’s composition, a person of ordinary skill in the art before the effective filing date of the claimed invention would have found it obvious to modify the composition of Okimoto to improve its wettability by increasing the molecular weight of the surface-modifying agent as taught by Adil and supported with evidence from Zhang. The combination of references would be a colloidal silica polishing solution for CMP wherein the surface-modifying group is polyoxyalkylene with a weight average molecular weight of 20,000, which arrives at the claimed invention.
Regarding claim 4, Okimoto, as modified by Adil, teaches the limitation wherein the surface-modifying group contains a urethane linkage (see Okimoto paragraph 0010 teaching the general structure of the surface-modifying group, wherein the connecting moiety A1 is selected from formulae (a11) to (a13); in paragraph 0011, formulae (a11) through (a13) all contain urethane linkages).
Regarding claim 5, Okimoto, as modified by Adil, teaches a polishing composition comprising the surface-modified colloidal silica according to claim 1 (see the above rejection of claim 1) and a dispersing medium (see Okimoto, paragraph 0033 teaching the dispersion of modified silica in water).
Response to Arguments
Applicant's arguments filed 21 November 2025 have been fully considered but they are not persuasive.
Claims 1, 4 and 5 stand rejected under 35 U.S.C. 103 as obvious over Okimoto (WO 2009/119178 A1) in view of Adil (PLoS ONE, 2020, 15(7), e0236837), with evidentiary support provided by Zhang (Applied Surface Science, 2012, 258, 8814–8818). Applicants argue that a person of ordinary skill in the art before the effective filing date of the claimed invention would not have been sufficiently motivated to modify Okimoto according to Adil because Okimoto allegedly teaches away from the use of higher molecular weight polymers, like those taught by Adil.
This argument is not found to be persuasive. Okimoto teaches a polymer comprising m units of polyoxyethylene, n units of polyoxypropylene, and p units of polyoxyethylene, wherein m + p is greater than 0, and wherein m is an integer between 0 and 170, n is an integer between 0 and 120, and p is an integer between 0 and 170. This means that Okimoto effectively teaches a polyoxyalkylene comprising up to 340 total units of polyoxyethylene and 0 units of polyoxypropylene. A polyoxyethylene chain with 340 repeating units has a molecular weight of 14,978, which falls short of the claimed “molecular weight of 20,000 or more”. Adil is cited as teaching surface-modified silica nanoparticles, wherein the surface modifier is polyethylene glycol (synonymous with polyoxyethylene) with a molecular weight of 20,000. Applicants argue that Okimoto teaches away from higher molecular weight polymers in paragraph 0017: “…when m+p is large, a polishing residue may be generated, and therefore m+p is preferably from 2 to 340, more preferably from 2 to 250.”
Although Okimoto explicitly states that polishing residue may be generated when m+p is large, this does not constitute “teaching away”. Firstly, it is noted Okimoto still teaches the maximum m+p value of 340; it isn’t recited as the “more preferabl[e]” embodiment, but MPEP 2123(II) states that preferred embodiments do not constitute a teaching away from non-preferred embodiments. If an m+p value of 340 were guaranteed to form a polishing residue, Okimoto would not have identified it as suitable for the claimed invention. So an m+p value of up to 340 is supported by the disclosure of Okimoto. Next, regarding whether Okimoto teaches away from the higher molecular weight polymer taught by Adil, the Examiner notes that the statement “polishing residue may be generated” does not sufficiently teach away from the use of higher molecular weight polymers; “may be generated” does not mean “will be generated”, and a person of ordinary skill in the art would likely interpret this statement as an optimization trade-off, not a teaching away. Okimoto does not explicitly state “if m+p > 340, then polishing residue will form”, because there likely isn’t a clear cut-off point; higher molecular weight polymers are implied to have a higher chance of forming undesirable polishing residue, but probabilistic statements are not sufficient to teach away. In other words, Okimoto does not define “large” according to a specific m+p threshold, and the cited paragraph suggests a results-oriented optimization rather than a binary failure point (i.e., “be aware that higher m+p values come with added risks”, versus “anything over m+p = 340 is guaranteed to form residue”).
A person of ordinary skill in the art before the effective filing date of the claimed invention would not have been discouraged from modifying Okimoto to use higher molecular weight polymers as taught by Adil, because even though Okimoto states that polishing residue may be generated when m+p is large, there is no explicit teaching away of values higher than m+p = 340, and no threshold value is provided to differentiate “large” from “too large”. Nothing in the disclosure of Okimoto rises to the level of discouragement that would negate a motivation to modify m+p to higher than 340. Accordingly, Okimoto is not considered to teach away from modification by Adil. The rejection of claims 1, 4 and 5 under 35 U.S.C. 103 is therefore maintained.
Conclusion
THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/R.P.L./Examiner, Art Unit 1731
/ANTHONY J GREEN/Primary Examiner, Art Unit 1731