Ex Parte Kawano et alDownload PDFPatent Trial and Appeal BoardFeb 19, 201310855562 (P.T.A.B. Feb. 19, 2013) Copy Citation UNITED STATES PATENT AND TRADEMARK OFFICE ____________ BEFORE THE PATENT TRIAL AND APPEAL BOARD ____________ Ex parte MASAYA KAWANO, YOSHIAKI YAMAMOTO and TAKAMASA ITO ____________ Appeal 2010-008674 Application 10/855,562 Technology Center 2800 ____________ Before CARL W. WHITEHEAD, JR., ERIC S. FRAHM and ANDREW J. DILLON, Administrative Patent Judges. WHITEHEAD, JR., Administrative Patent Judge. DECISION ON APPEAL Appeal 2010-008674 Application 10/855,562 2 STATEMENT OF THE CASE Appellants are appealing claims 1, 2, 4-6 and 9-11. Appeal Brief 4. We have jurisdiction under 35 U.S.C. § 6(b) (2012). We affirm. Introduction The present invention is directed to a semiconductor device having interconnections and a via-plug for connecting the interconnections together wherein the configuration of the interconnection structure reduces stress migration. Specification 1. Illustrative Claim 1. A semiconductor device having a first interconnection, a via-plug that is formed in a via-hole and is connected to said first interconnection, said via-hole having a top plane, and a second interconnection that is formed over said top plane of said via-hole, said second interconnection having a top surface that is substantially parallel with said top plane of said via- hole and that is flat directly above said via-plug; wherein: said via-hole is filled with metal up to a level of said top plane of said via-hole; a plug sidewall angle in a cross-sectional shape of said via-plug is formed between two lines: a first line parallel to a surface of said first interconnection passing Appeal 2010-008674 Application 10/855,562 3 through a selected point on a sidewall of said via-plug and a first point on a central axis of said via- plug, and a second line tangent to said selected point and passing through a second point on said central axis, wherein an angle of depression from said first line that is parallel to the surface of said first interconnection is a positive angle, and an angle of elevation from said first line that is parallel to the surface of said first interconnection is a negative angle, and in the cross-sectional shape of said via-plug, said plug sidewall angle is a positive angle; and there are at least two points between a base and a top of said via-plug on at least one of two sidewalls of said via-plug cross-sectional shape at which said plug sidewall angle attains a maximum value, and there is a point between a base and a top of said via-plug on at least one of two sidewalls of said via-plug cross-sectional shape at which said plug sidewall angle attains a positive minimum value, wherein said point at which said plug sidewall angle attains a positive minimum value is at a position above half of a depth of said via-hole, and wherein said plug sidewall angle any selected points of the sidewalls of said via-plug is equal to or less than 90 degrees. Rejection on Appeal Claims 1, 2, 4-6 and 9-11 stand rejected under 35 U.S.C. § 103 (a) as being unpatentable over Chen (U.S. Patent Number 6,352,938 B2; issued March 5, 2002), Grewal (U.S. Patent Number 4,764,245; issued August 16, Appeal 2010-008674 Application 10/855,562 4 1988) and Meng (U.S. Patent Number 5,453,403; issued September 26, 1995). Answer 3-8. Issue on Appeal Do Chen, Grewal, and Meng, either alone or in combination, disclose a semiconductor device having an interconnection structure that reduces stress migration in the manner claimed by Appellants? ANALYSIS We have reviewed the Examiner’s rejections in light of Appellants’ arguments that the Examiner has erred. We disagree with Appellants’ conclusions. We concur with the findings and reasons set forth by the Examiner in the action from which this appeal is taken and the reasons set forth by the Examiner in the Answer in response to Appellants’ Appeal Brief. However, we highlight and address specific findings and arguments for emphasis as follows. Appellants argue that the Examiner’s reliance upon Grewal is improper because Grewal discloses that only the sidewall angle of the contact hole should be between 60º and 90º, Grewal’s Figure does not disclose or suggest the claimed via-plug sidewall configuration and Grewal’s Figure is not drawn to scale. Appeal Brief 14. Appellants conclude that the Examiner’s assertion that it would be obvious to the ordinary artisan that Grewal’s Figure discloses “wherein said point at which said plug sidewall angle attains a positive minimum value is at a position above half of a depth of said via-hole” as required by the claim [1] is unfounded. Id. Appeal 2010-008674 Application 10/855,562 5 We do not find Appellants’ arguments to be persuasive because it is not clear why Grewal’s disclosure of the sidewall angle being between 60º and 90º is relevant to the claimed invention since Appellants attempt to define the claimed angle based upon different parameters. See claims 1, 9; see also Appeal Brief 12-16. Appellants attempt to distinguish the “plug sidewall angle” by orienting lines that are supposed to demonstrate that Grewal does not disclose the claimed “plug sidewall angle.” Appeal Brief 14-15. However it is apparent from Appellants’ interpretation of Grewal’s Figure that the same line orientation or parameters are not being employed in the same manner as the claimed invention. See Appellants’ Figure 3; see also Appeal Brief 15. However, the Examiner finds that Grewal discloses the claimed “plug sidewall angle” when parameters or line orientations are employed in the same manner as Appellants’ plug sidewall. Answer 6. Therefore we agree with the Examiner’s findings that Grewal discloses the claimed “plug sidewall angle.” We also do not find Appellants’ arguments in regard to Grewal’s Figure alleged failure for not being drawn to scale to be persuasive because the Figure does not have to be precise to demonstrate or disclose the general spatial relationship of a via-plug as recited in the claims. Claim 1 recites the structure of the via-plug or hole in broad terms -“wherein said point at which said plug sidewall angle attains a positive minimum value is at a position above half of a depth of said via-hole.” We agree with the Examiner’s findings that Grewal discloses the claimed “positive minimum value” as recited in claim 1 because the claimed “positive minimum value” is not a definitive spatial relation but a relative one described in broad terms. See Answer 5, 9. Appeal 2010-008674 Application 10/855,562 6 Therefore we sustain the Examiner’s rejection of claim 1 as well as independent claim 9, which is commensurate in scope. Further, we sustain the Examiner’s rejection of dependent claims 2, 4-6, 10, and 11, not separately argued, for the same reason stated above. DECISION The obviousness rejection of claims 1, 2, 4-6 and 9-11 is affirmed. No time period for taking any subsequent action in connection with this appeal may be extended under 37 C.F.R. § 1.136(a)(1)(iv). See 37 C.F.R. § 41.50(f). AFFIRMED tkl Copy with citationCopy as parenthetical citation