DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Claim Objections
Claims 11-19 are objected to because of the following informalities: claim 11, lines 3-4 contains the phrase, “a substrate” when it should read the substrate. Claim 12-19 are also objected to due to their dependency. Appropriate correction is required.
Claim 20 is objected to because of the following informalities: claim 20, line 3 contains the phrase, “a substrate” when it should read the substrate. Appropriate correction is required.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claims 1, 4-10, and 20 are rejected under 35 U.S.C. 103 as being unpatentable over Kang et al. (KR 20050026270 A, hereinafter “Kang”) in view of Lin et al. (United States Patent Application Publication No. US 2020/0185226 A1, hereinafter “Lin”).
In reference to claim 1, Kang discloses a similar method. Fig. 1a-1f and 2b of Kang disclose a method for fabricating a semiconductor device which comprises sequentially forming, on a substrate (10) that includes a lower wiring pattern (12), an etch stop film (14), an interlayer insulating film (15). Although not shown, it is understood that a hard mask pattern is formed to pattern an opening on the substrate (10) such that a trench is formed in the interlayer insulating film (15), using the hard mask pattern, that exposes a surface of the etch stop film (14) at a bottom of the trench. The etch stop film (14) is understood to be a homogenous film. A trench is formed in the interlayer insulating film (330), using the hard mask pattern (355 – fig. 6c, 340 – fig. 8b), that exposes a surface of the etch stop film (320) at a bottom of the trench. The etch stop film (320) includes a first portion exposed by the trench. At the bottom of the trench, a portion of the first portion of the etch stop film (320) and the hard mask pattern (355 – fig. 6c, 340 – fig. 8b) is removed by using a first wet etching process (p. 10 of machine translation). A remainder of the first portion of the etch stop film (320) at the bottom of the trench to expose the lower wiring pattern (310) is removed by a second etching process. Kang does not disclose using a second wet etching process to remove the etch stop film (320). However Lin discloses the known method of wet etching to remove an etch stop film (p. 15, paragraph 132, p. 15-16, paragraph 134). It would be obvious to use a second wet etching process to remove the etch stop film since choosing from a finite number of identified, predictable solutions ("obvious to try") with a reasonable expectation of success have been found to be obvious. KSR International Co. v. Teleflex Inc., 550 U.S. 398, 416 (2007). In view of the above, it would therefore be obvious to use a second wet etching process to remove the etch stop film in the Kang method.
With regard to claim 4, in fig. 6a-6i and 8a-8e of Kang, after the first wet etching process, a first rounding portion (S2, S3 – fig. 6f, unlabeled in fig. 8e) is formed on an upper portion of the interlayer insulating film (330) adjacent a top of the trench using a top corner rounding (TCR) process. In the method of Kang constructed in view of Lin, the top corner rounding process is done in the same step as the second wet etching process. Kang does not disclose that the top corner rounding process is done before the second wet etching process. However the transposition of process steps or the splitting of one step into two, where the processes are substantially identical or equivalent in terms of function, manner, and result, was held to not patentably distinguish the processes. Ex parte Rubin, 128 USPQ 440 (Bd. App. 1959); New Wrinkle, Inc., et al. v. Watson, 1953 C.D. 18, 670 O.G. 306, 204 F.2d 35, 96 USPQ 436, 438. Thus it would be obvious to split the simultaneous top corner rounding/second wet etching process step into two separate steps in the method of Kang constructed in view of Lin.
In reference to claim 5, fig. 6a-6i and 8a-8e of Kang show that the trench has a width that decreases as the trench extends toward the substrate (300, 310).
With regard to claim 6, fig. 8a-8e of Kang show that a first surface of the etch stop film (320) is in contact with the interlayer insulating film (330), and a second surface of the etch stop film (320) that is opposite the first surface is in contact with the substrate (300).
In reference to claim 7, fig. 6a-6i and 8a-8e of Kang show that after the second wet etching process, a wiring pattern (360, 370, 380) is formed in the trench. Kang makes it clear (p. 15 of the machine translation) that the same wiring pattern (360, 370, 380) is formed in the trench shown in fig. 6a-6i.
With regard to claim 8, the forming of the wiring pattern in the trench includes forming a conductive barrier film (360 or 370) along sidewalls and a bottom surface of the trench and forming a conductive filling film (380) on the conductive barrier film (360 or 370).
In reference to claim 9, in fig. 6a-6i and 8a-8e of Kang, a second rounding portion (S1 – fig. 6f, unlabeled in fig. 8e) is formed adjacent the bottom of the trench. In the method of Kang constructed in view of Lin, the second wet etching process forms the second rounding portion (Kang: S1 – fig. 6f, unlabeled in fig. 8e).
With regard to claim 10, fig. 6f and 8e of Kang show that the second rounding portion (S1 – fig. 6f, unlabeled in fig. 8e) includes a convex portion.
In reference to claim 20, Kang discloses a similar method. Fig. 6a-6i and 8a-8e of Kang disclose a method for fabricating a semiconductor device which comprises sequentially forming, on a substrate (300, 310) that includes a wiring pattern (310), an etch stop film (320), an interlayer insulating film (330), and a hard mask pattern (355 – fig. 6c, 340 – fig. 8b) including an opening on the substrate (300, 310). The etch stop film (320) is a homogenous film (p. 6 of the machine translation). A trench is formed in the interlayer insulating film (330), using the hard mask pattern (355 – fig. 6c, 340 – fig. 8b) to expose the etch stop film (320) at a bottom of the trench. A width of the trench decreases as the trench extends towards the substrate (300, 310). At the bottom of the trench, a portion of the first portion of the etch stop film (320) and the hard mask pattern (355 – fig. 6c, 340 – fig. 8b) is removed by using a first wet etching process (p. 10 of machine translation). A first rounding portion (S2, S3 – fig. 6f, unlabeled in fig. 8e) is formed on the interlayer insulating film (330) using a top corner rounding process (p. 10 of machine translation). A remainder of the first portion of the etch stop film (320) at the bottom of the trench is removed to expose the wiring pattern (310) is removed by a second etching process. Kang does not disclose using a second wet etching process to remove the etch stop film (320). However Lin discloses the known method of wet etching to remove an etch stop film (p. 15, paragraph 132, p. 15-16, paragraph 134). It would be obvious to use a second wet etching process to remove the etch stop film since choosing from a finite number of identified, predictable solutions ("obvious to try") with a reasonable expectation of success have been found to be obvious. KSR International Co. v. Teleflex Inc., 550 U.S. 398, 416 (2007). In view of the above, it would therefore be obvious to use a second wet etching process to remove a remainder of the first portion of the etch stop film at the bottom of the trench in the Kang method.
Claim 2 is rejected under 35 U.S.C. 103 as being unpatentable over Kang in view of Lin as applied to claim 1 above and further in view of Manning (United States Patent Application Publication No. US 2005/0239246 A1, hereinafter “Manning”).
In reference to claim 2, Kang does not disclose that the etch stop film is made of aluminum oxide. However Manning discloses the known use of aluminum oxide as an etch stop film material (abstract, p. 3, paragraph 30). The applicant is reminded in this regard that it has been held that the selection of a known material based on its suitability for its intended use would be entirely obvious. See Sinclair & Carroll Co. v. Interchemical Corp., 325 U.S. 327, 65 USPQ 297 (1945) ("Reading a list and selecting a known compound to meet known requirements is no more ingenious than selecting the last piece to put in the last opening in a jig-saw puzzle." 325 U.S. at 335, 65 USPQ at 301.). See also In re Leshin, 277 F.2d 197, 125 USPQ 416 (CCPA 1960) (selection of a known plastic to make a container of a type made of plastics prior to the invention was held to be obvious). See MPEP 2144.07. In view of the above, it would therefore be obvious to use aluminum oxide for the etch stop film.
Claim 3 is rejected under 35 U.S.C. 103 as being unpatentable over Kang in view of Lin as applied to claim 1 above and further in view of Thompson (United States Patent Application Publication No. US 2003/0064601 A1, hereinafter “Thompson”).
In reference to claim 3, Kang does not disclose the exact thickness of the etch stop film as that claimed by the applicant. However Thompson discloses that making the etch stop film thinner decreases the RC time delay of the interconnects in the device (p. 1, paragraph 5) which is a known goal in the art (p. 1, paragraph 2). Thus Thompson makes it clear that the thickness of the etch stop film is a result effective variable. It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to adjust the thickness of the etch stop film, since it has been held that discovering an optimum value of a result effective variable involves only routine skill in the art. In re Boesch, 617 F.2d 272, 205 USPQ 215 (CCPA 1980). Therefore claim 3 is not patentable over Kang, Lin, and Thompson.
Claims 11, 12, and 18 are rejected under 35 U.S.C. 103 as being unpatentable over Kang in view of Manning.
In reference to claim 11, Kang discloses a similar method. Fig. 6a-6i and 8a-8e of Kang disclose a method for fabricating a semiconductor device which comprises sequentially forming, on a substrate (300, 310) that includes a lower wiring pattern (310), an etch stop film (320), an interlayer insulating film (330), and a hard mask pattern (355 – fig. 6c, 340 – fig. 8b) including an opening on the substrate (300, 310). The etch stop film (320) is a homogenous film (p. 6 of the machine translation). A trench is formed in the interlayer insulating film (330), using the hard mask pattern (355 – fig. 6c, 340 – fig. 8b), that exposes a surface of the etch stop film (320). The trench has a top portion adjacent the hard mask pattern (355 – fig. 6c, 340 – fig. 8b) and a bottom adjacent the etch stop film (320). The etch stop film (320) includes a first portion exposed by the trench. Kang discloses that at the bottom of the trench, a portion of the first portion of the etch stop film (320) and the hard mask pattern (355 – fig. 6c, 340 – fig. 8b) is removed by using a first wet etching process (p. 10 of machine translation). A first rounding portion (S2, S3 – fig. 6f, unlabeled in fig. 8e) is formed in an upper portion of the interlayer insulating film (330) adjacent the top portion of the trench by using a first dry etching process (p. 10 of machine translation).
Kang does not disclose that the etch stop film is made of aluminum oxide. However Manning discloses the known use of aluminum oxide as an etch stop film material (abstract, p. 3, paragraph 30). The applicant is reminded in this regard that it has been held that the selection of a known material based on its suitability for its intended use would be entirely obvious. See Sinclair & Carroll Co. v. Interchemical Corp., 325 U.S. 327, 65 USPQ 297 (1945) ("Reading a list and selecting a known compound to meet known requirements is no more ingenious than selecting the last piece to put in the last opening in a jig-saw puzzle." 325 U.S. at 335, 65 USPQ at 301.). See also In re Leshin, 277 F.2d 197, 125 USPQ 416 (CCPA 1960) (selection of a known plastic to make a container of a type made of plastics prior to the invention was held to be obvious). See MPEP 2144.07. In view of the above, it would therefore be obvious to use aluminum oxide for the etch stop film.
With regard to claim 12, the first dry etching process of Kang further includes removing a remainder of the first portion (S1) of the etch stop film (320) at the bottom of the trench and exposing the lower wiring pattern (310) in the trench.
In reference to claim 18, fig. 6a-6i and 8a-8e of Kang show that a width of the trench decreases as the trench extends towards the substrate (300, 310).
Claim 16 is rejected under 35 U.S.C. 103 as being unpatentable over Kang in view of Manning as applied to claim 11 above and as further evidenced by Komada et al. (United States Patent Application Publication No. US 2003/0068582 A1, hereinafter “Komada”).
In reference to claim 16, Kang discloses that the interlayer insulating film (330) is made of FSG (p. 18 of the machine translation). Komada discloses that FSG is a known low-k (k is the dielectric constant) dielectric material (p. 1, paragraph 6). Thus the method of Kang constructed in view of Manning meets claim 16.
Claim 17 is rejected under 35 U.S.C. 103 as being unpatentable over Kang in view of Manning as applied to claim 11 above and in further view of Lee et al. (United States Patent Application Publication No. US 2016/0079115 A1, hereinafter “Lee”).
In reference to claim 17, Kang does not disclose that the hard mask pattern includes at least one of titanium, titanium nitride, titanium oxide, tungsten, tungsten nitride, and tungsten oxide. However Lee discloses the known use of titanium, titanium nitride, titanium oxide, tungsten, tungsten nitride, and tungsten oxide as a hard mask pattern material (p. 2, paragraph 33). The applicant is reminded in this regard that it has been held that the selection of a known material based on its suitability for its intended use would be entirely obvious. See Sinclair & Carroll Co. v. Interchemical Corp., 325 U.S. 327, 65 USPQ 297 (1945) ("Reading a list and selecting a known compound to meet known requirements is no more ingenious than selecting the last piece to put in the last opening in a jig-saw puzzle." 325 U.S. at 335, 65 USPQ at 301.). See also In re Leshin, 277 F.2d 197, 125 USPQ 416 (CCPA 1960) (selection of a known plastic to make a container of a type made of plastics prior to the invention was held to be obvious). See MPEP 2144.07. In view of the above, it would therefore be obvious to use titanium, titanium nitride, titanium oxide, tungsten, tungsten nitride, and tungsten oxide for the hard mask pattern.
Claim 19 is rejected under 35 U.S.C. 103 as being unpatentable over Kang in view of Manning as applied to claim 11 above and in further view of Thompson.
In reference to claim 19, Kang does not disclose the exact thickness of the etch stop film as that claimed by the applicant. However Thompson discloses that making the etch stop film thinner decreases the RC time delay of the interconnects in the device (p. 1, paragraph 5) which is a known goal in the art (p. 1, paragraph 2). Thus Thompson makes it clear that the thickness of the etch stop film is a result effective variable. It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to adjust the thickness of the etch stop film, since it has been held that discovering an optimum value of a result effective variable involves only routine skill in the art. In re Boesch, 617 F.2d 272, 205 USPQ 215 (CCPA 1980). Therefore claim 19 is not patentable over Kang, Manning, and Thompson.
Allowable Subject Matter
Claims 13-15 are 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 AND if the language of base claim (claim 11) is corrected (see above section titled Claim Objections).
The following is a statement of reasons for the indication of allowable subject matter: in the examiner’s opinion, it would not be obvious to implement a method for fabricating a semiconductor device which comprises sequentially forming, on a substrate that includes a lower wiring pattern, a homogenous aluminum oxide etch stop film, an interlayer insulating film, and a hard mask pattern with an opening on the substrate, forming a trench in the interlayer insulating film, using the hard mask pattern, that exposes a surface of the etch stop film, such that the trench has a top portion adjacent the hard mask pattern and a bottom adjacent the etch stop film, removing the hard mask pattern and a portion of a first portion of the etch stop film at the bottom of the trench by using a first wet etching process, forming a first rounding portion on an upper portion of the interlayer insulating film adjacent the top portion of the trench by using a first dry etching process which is followed by using a second wet etching process to remove a second portion of the etch stop film at the bottom of the trench as described by the applicant in claim 13.
Conclusion
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/KEVIN QUINTO/Examiner, Art Unit 2893
/Britt Hanley/Supervisory Patent Examiner, Art Unit 2893
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