Ex Parte 6,815,321 et alDownload PDFBoard of Patent Appeals and InterferencesJul 10, 201295000483 (B.P.A.I. Jul. 10, 2012) Copy Citation UNITED STATES PATENT AND TRADEMARK OFFICE UNITED STATES DEPARTMENT OF COMMERCE United States Patent and Trademark Office Address: COMMISSIONER FOR PATENTS P.O. Box 1450 Alexandria, Virginia 22313-1450 www.uspto.gov APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO. 90/009,482 06/08/2009 6,815,321 051700-5005-US 9596 24341 7590 07/11/2012 MORGAN, LEWIS & BOCKIUS, LLP. (PA) 2 PALO ALTO SQUARE 3000 EL CAMINO REAL, SUITE 700 PALO ALTO, CA 94306 EXAMINER KIELIN, ERIK J ART UNIT PAPER NUMBER 3992 MAIL DATE DELIVERY MODE 07/11/2012 PAPER Please find below and/or attached an Office communication concerning this application or proceeding. The time period for reply, if any, is set in the attached communication. PTOL-90A (Rev. 04/07) UNITED STATES PATENT AND TRADEMARK OFFICE UNITED STATES DEPARTMENT OF COMMERCE United States Patent and Trademark Office Address: COMMISSIONER FOR PATENTS P.O. Box 1450 Alexandria, Virginia 22313-1450 www.uspto.gov APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO. 95/000,483 06/09/2009 6815321 051700-5006-US 9039 24341 7590 07/11/2012 MORGAN, LEWIS & BOCKIUS, LLP. (PA) 2 PALO ALTO SQUARE 3000 EL CAMINO REAL, SUITE 700 PALO ALTO, CA 94306 EXAMINER KIELIN, ERIK J ART UNIT PAPER NUMBER 3992 MAIL DATE DELIVERY MODE 07/11/2012 PAPER Please find below and/or attached an Office communication concerning this application or proceeding. The time period for reply, if any, is set in the attached communication. PTOL-90A (Rev. 04/07) UNITED STATES PATENT AND TRADEMARK OFFICE ____________ BEFORE THE BOARD OF PATENT APPEALS AND INTERFERENCES ____________ CHIMEI INNOLUX CORP. Requester and Respondent v. Patent of LG DISPLAY CO., LTD. Patent Owner and Appellant ____________________ Appeal 2012-004203 Reexamination Control 95/000,483 & 90/009,482 Patent US 6,815,321 B2 Technology Center 3900 ____________ Before HOWARD B. BLANKENSHIP, ALLEN R. MACDONALD, and JOSIAH C. COCKS, Administrative Patent Judges. BLANKENSHIP, Administrative Patent Judge DECISION ON APPEAL Appeal 2012-004203 Reexamination Control 95/000,483 & 90/009,482 Patent US 6,815,321 B2 2 STATEMENT OF THE CASE The Patent Owner appeals under 35 U.S.C. § 134(b) from the final decision of the Examiner to reject claims 7-10, 12, 14, 16-20, and 22. Claims 1-6, 11, 13, 15, and 21 are not subject to reexamination. Claims 10 and 16 have been amended. We have jurisdiction under 35 U.S.C. § 315(a). Oral hearing was April 25, 2012. We affirm. Invention Figure 4C of the '321 patent is reproduced below. Figure 4C illustrates a process for fabricating a thin-film transistor. '321 patent col. 5, ll. 56-58. A metal such as aluminum (Al) is deposited on a substrate 41 to form a first metal layer 43. A second metal layer 45 is formed from a metal such as molybdenum (Mo) and deposited on the first metal layer 43. Id. at col. 5, ll. 59-63. The second metal layer 45 is preferably patterned to have the width W2 which is narrower than the width W1 of the first metal layer 43 such that Appeal 2012-004203 Reexamination Control 95/000,483 & 90/009,482 Patent US 6,815,321 B2 3 W1 - W2 is between about 1µm and 4 µm. Each side portion of the second metal layer 45 preferably has a width larger than about 0.5 µm and less than about 2 µm. Id. at col. 6, ll. 17-26. Representative Claim 7. A method of forming a thin film transistor comprising: forming a first metal layer on a substrate, forming a second metal layer on the first metal layer; simultaneously patterning the first and second metal layers to form a double-layered metal gate, so that a total width of the first metal layer is greater than a total width of the second metal layer by about 1 to 4 µm. Prior Art Kakuda US 5,162,933 November 10, 1992 Nakamura JP Hei 7-297185 November 10, 1995 Oikawa JP Hei 4-50822 February 19, 1992 S. Mayumi, et al., A Novel A1 Edge Cutting Process for Multilevel Metallization, 1987 Proceedings Fourth International, IEEE VLSI Multilevel Interconnection Conference, pp. 78-84 (June 1987). Appeal 2012-004203 Reexamination Control 95/000,483 & 90/009,482 Patent US 6,815,321 B2 4 Owner’s Contentions Owner contends that the Examiner erred in rejecting claims 7-10, 12, 14, 16-20, and 22 over the prior art. The Examiner adopted four grounds of rejection proposed by Requester. I. Claims 7-10, 12, 14, 16, 20, and 22 stand rejected under 35 U.S.C. § 102(b) as being anticipated by Kakuda. II. Claims 7-10, 12, 14, 16-20, and 22 stand rejected under 35 U.S.C. § 103(a) as being unpatentable over Nakamura and Kakuda. III. Claims 7-10, 12, 14, 16, 18-20, and 22 stand rejected under 35 U.S.C. § 103(a) as being unpatentable over Oikawa. IV. Claims 7-10, 12, 14, 16, 18-20, and 22 stand rejected under 35 U.S.C. § 103(a) as being unpatentable over Oikawa and Mayumi. ANALYSIS The Examiners Right of Appeal Notice (“RAN”; mailed May 18, 2011) is hereby incorporated by reference. We adopt the Examiner’s findings as our own except for those findings with which we may express disagreement in the analysis that follows. We will discuss three of the grounds of rejection in this opinion. Initially, however, we note that two terms that are relevant in this appeal -- “hillocks” and “step coverage” -- do not appear to be expressly defined in this record. The precise definitions are not critical, because the prior art of record reflects that “hillocks” are to be avoided and good “step coverage” is to be encouraged. However, for a general understanding of the subject matter we note the following definitions: Appeal 2012-004203 Reexamination Control 95/000,483 & 90/009,482 Patent US 6,815,321 B2 5 Hillocks are “bumps that form in a thin film during heating and cooling,” IC Knowledge - Glossary of Semiconductor Terminology 2012 1 ; and Step Coverage is “the ratio of the thickness of a film over a step edge to the thickness in a flat area. Most metallization processes result in a thinner metal layer over a step than in a flat area.” Id. Section 102(b) -- Kakuda The Reference Figure 8 of Kakuda is reproduced below. Figure 8 illustrates in section a thin film transistor and its vicinity in an active matrix structure. The gate line 13 has a structure in which a MoCrx layer 13b overlies an aluminum layer 13a. Kakuda col. 10, ll. 30-34, 45-47. The side wall of the pattern has an inclination of approximately 50 degrees such that a defect in a stepped portion on the side wall could be avoided. Id. at ll. 51-54. 1 available at http://www.icknowledge.com (last visited June 27, 2012). Appeal 2012-004203 Reexamination Control 95/000,483 & 90/009,482 Patent US 6,815,321 B2 6 The Rejection The Examiner finds that Kakuda describes the aluminum layer 13a as having a taper angle of 50 degrees. In view of the disclosed thicknesses of the MoCr layer and the aluminum layer, the Examiner finds that instant claim 1 is anticipated because the principles of trigonometry demonstrate that the first metal layer 13a is wider than the second metal layer 13b by 1.68 µm, which falls within the claimed range of about 1 to 4 µm. RAN at 11-14. 2 Owner does not dispute the Examiner’s basic calculations. However, Owner contends that the Examiner’s finding that Kakuda describes the aluminum layer as having a taper angle of 50 degrees is in error. Owner contests the finding by advancing three arguments. Owner asserts that the Examiner erroneously assumes that: (1) when referring to a “pattern,” Kakuda is not referring to the molybdenum-based alloy layer (13b in Figure 8), but to the entire multi-layered structure (13a and 13b in Figure 8); (2) the side-walls of the aluminum layer (13a) in this multi-layered structure are co-planar, continuous, and non-stepped with respect to the molybdenum- based alloy layer (13b); and (3) the side-walls of the aluminum layer (13a) in this multi-layered structure are non-curved. App. Br. 12-13. Kakuda’s “Pattern” Owner refers to Dr. James O’Connor’s declaration of February 25, 2010 (“O’Connor Decl.”), contained in the Appeal Brief’s 2 The Examiner’s Answer incorporates by reference the RAN. Appeal 2012-004203 Reexamination Control 95/000,483 & 90/009,482 Patent US 6,815,321 B2 7 Evidence Appendix, in support of the view that Kakuda fails to disclose that the aluminum layer has a taper angle of 50 degrees. An initial problem with the O’Connor Declaration is the hearsay nature of the testimony. The Declaration contains multiple references to an “Expert Report” by “Dr. Gary W. Rubloff” that has not been provided as evidence in this appeal. See O’Connor Decl. ¶ 2. In any event, Owner refers to and relies on (App. Br. 16) paragraph 22 of the O’Connor declaration for the statement that “[t]he focus of the Kakuda reference, is the sidewall of molybdenum.” The declaration continues: In summary, Dr. Rubloff found “[t]hus, with the aluminum and molybdenum structure of Experiment II, Kakuda is clearly concerned with the side wall of the top molybdenum layer, not the aluminum layer.” Rubloff Expert Report ¶ 173. Hence, the section of Kakuda cited by the Office Action does not disclose an aluminum layer with an incline angle of 50°. The Office Action “does not cite any disclosure of Kakuda to support [the] conclusions that the 50° angle refers to the aluminum layer.” Rubloff Expert Report ¶ 173. As a result of my independent review and analysis, I agree with this conclusion. O’Connor Decl. ¶ 23. At paragraph 21 of the Declaration, Dr. O’Connor quotes and concurs with a statement from the “Rubloff Expert Report ¶ 172: “I believe that a close review of the Kakuda reference, as a whole, suggests that the 50° angle identified refers to the angle of the top molybdenum layer, not the aluminum layer.” The basis for the conclusion appears to be stated at paragraph 22, where the “Rubloff Expert Report ¶ 173” alleges that the “focus” of the Appeal 2012-004203 Reexamination Control 95/000,483 & 90/009,482 Patent US 6,815,321 B2 8 Kakuda reference is the side wall of the molybdenum, pointing to a different embodiment (“Experiment III”) than that relied upon by the rejection (“Experiment II”). We do not have the “Rubloff Expert Report” and its 173 (or more) paragraphs for evaluation of the quoted statements in context. We are not persuaded that Kakuda’s disclosure of the 50° angle refers to the aluminum layer but not the molybdenum layer. The factual basis for the opinion rests on the allegation that the reference is concerned with the side wall of the molybdenum but not the aluminum layer in an embodiment that is not that relied upon for showing anticipation, which is a further detriment to the credibility of the testimony. We have also considered the attorney arguments submitted to show that the 50 degree angle disclosed by Kakuda does not refer to the aluminum layer 13a in Figure 8 -- i.e., that the “pattern” refers to molybdenum layer 13b alone. We can agree with Owner to the extent that portions of the reference are not precise in the use of the term “pattern.” However, the “pattern” in the context of the paragraph at column 10, lines 36 through 54 relates to the formation of a photoresist pattern (l. 40) for etching of the gate electrodes and related structures. Thus, the “pattern” does not appear to refer to the molybdenum layer 13b alone. 3 The “pattern” refers at least to 3 We observe that the subject '321 patent refers to multiple “patterned” layers in the description of the related art (col. 2, ll. 6-28) and that in preferred embodiments of the invention a single photoresist step is used to “pattern” both the first and second metal layer simultaneously (col. 6, ll. 6- 9). Appeal 2012-004203 Reexamination Control 95/000,483 & 90/009,482 Patent US 6,815,321 B2 9 the laminated molybdenum and aluminum films that are patterned by etching. Kakuda col. 10, ll. 22-29. Further, Kakuda states that the MoCrx thin film is easy to etch with the aluminum etchant and that the “laminated” film patterned by etching “has gently sloping side walls through the substrate” (col. 10, ll. 22-25). We find it highly unlikely that the “laminated” film with sloping side walls refers to the single molybdenum layer and does not include the aluminum layer -- especially when the reference, in the same paragraph, describes “laminating the MoCrx thin film and the aluminum film.” Kakuda col. 10, ll. 25-29. Further, the “defect” avoided in a step portion of the film (col. 10, ll. 53-54) could refer, as Owner argues, to a defect in the molybdenum film (col. 7, ll. 44-51), but that would not preclude the aluminum film from having an inclination of approximately 50 degrees. Moreover, we find it more likely that the avoided “defect” refers to improved step coverage as opposed to a “defect” in the molybdenum film alone. See Dr. Richard B. Fair Declaration (“Fair Decl.”), in Evidence Appendix of Requester’s (Respondent) Brief, at ¶¶ 14-16. Further, we agree that patent drawings generally do not define precise proportions and may not be relied on to show particular sizes if the specification is completely silent on the issue. App. Br. 20. See In re Wright, 569 F.2d 1124, 1127 (CCPA 1977) (“Absent any written description in the specification of quantitative values, arguments based on measurement of a drawing are of little value.”); In re Wilson, 312 F.2d 449, 454 (CCPA 1963) (“Patent drawings are not working drawings [and arguments are not persuasive when based on a] drawing obviously never intended to show the Appeal 2012-004203 Reexamination Control 95/000,483 & 90/009,482 Patent US 6,815,321 B2 10 dimensions of anything.”). In this case, the Examiner is not taking any quantitative values from Figure 8 of Kakuda but from the reference’s written description. However, Figure 8 shows an aluminum layer 13a having inclined walls. In view of Kakuda’s disclosure that the side wall of the pattern has an inclination of approximately 50 degrees, a reasonable inference is drawn that the aluminum layer walls are depicted as inclined to be illustrative of the disclosed 50 degree inclination. 4 Kakuda’s Al Layer Sidewalls Owner argues that the aluminum layer 13a sidewalls are curved rather than linear as shown (Kakuda Fig. 8). However, Owner has failed to establish (1) that the sidewalls are curved and (2) even if curved, why the result of the relative width falling within the claimed range would be different. The factual basis for Owner’s arguments (App. Br. 17-24) relies on three documents. The principal document is a “Y.I. Choi et al.” publication that the Examiner refused to enter because it was a second submission after the Action Closing Prosecution (Ans. 2). There is no indication in the record that Owner petitioned the Examiner’s refusal to enter the evidence. Accordingly, we have not considered the Choi publication. See 37 C.F.R. § 41.67(c)(1)(ix) (“Reference to unentered evidence is not permitted in the brief.”). 4 The subject '321 patent indicates that the lateral surfaces of the second metal layer 45 (Fig. 4B) are preferably etched to have a substantially rectangular or inclined shape (col 6, ll. 29-31), and Figure 4B shows an inclined shape. Appeal 2012-004203 Reexamination Control 95/000,483 & 90/009,482 Patent US 6,815,321 B2 11 Owner also refers to Mayumi, 5 in particular Figure 7(a), as support for the conclusion that an isotropic etch “typically” results in curved sidewalls. App. Br. 18-19. However, the remarks fail to explain how one of ordinary skill in the art would reach the conclusion based on the disclosure of Mayumi. Further, Owner does not refer to any expert testimony in support of the allegation. Moreover, we find no satisfactory response to the Examiner’s finding (RAN 52- 54) that references of record show that the relative etching rate for molybdenum can be controlled such that the side edge portions of the adjacent aluminum film are inclined at particular angles. Nor do we find a response to Requester’s observation (Respondent Br. 7) that Seiki (US 5,811,835) discloses non-curved aluminum side walls having an inclination angle. The final document that Owner relies on is the Kakuda reference itself. According to Owner, Kakuda at column 13, lines 29 through 44 tends to show that it was known that the etch rate of each layer in a double-layer structure must be identical to form a “non-stepped double-layer structure with continuous and identical inclination angles across both layers.” App. Br. 21. However, Owner’s response to the Examiner’s finding that the relative etching rate for molybdenum can be controlled is based on evidence that is not before us (“Choi et al.”). Section 102(b) Summary/Conclusion Upon consideration of the Examiner’s findings in the RAN and supporting evidence, and Owner’s evidence and arguments in response, we 5 The reference is applied in present § 103(a) rejections. Appeal 2012-004203 Reexamination Control 95/000,483 & 90/009,482 Patent US 6,815,321 B2 12 find that a preponderance of the evidence supports the Examiner’s finding that Kakuda discloses that the width difference of the molybdenum and aluminum layers falls within the claimed range of about 1 to 4 µm. We therefore sustain the § 102(b) rejection of claim 7. Claims 8-10, 12, 14, 16, 20, and 22, not separately argued, fall with claim 7. Section 103(a) -- Nakamura and Kakuda We refer to the Examiner’s findings in the RAN (at 16-22) in support of the rejection of representative claim 7 over Nakamura and Kakuda. Owner advances two arguments in response to the rejection (App. Br. 24- 25). Owner’s first argument rests on the allegation that Kakuda fails to teach a relative width of layers within the claimed range, which we find not persuasive for the reasons noted in our review of the rejection of claim 7 as being anticipated by Kakuda. Second, Owner submits that one skilled in the art would not combine the structures of Nakamura with the structures of Kakuda. Owner’s only reference to evidence in support of the contention is to paragraph 27 of the O’Connor Declaration. We agree with the Examiner and Requester that an allegation that Nakamura has solved the problems stated in the publication and thus “Nakamura would not look to Kaduda” (O’Connor Decl. ¶ 27) fails to demonstrate any defect in the Examiner’s prima facie case of obviousness. The proper question is “whether the combination was obvious to a person with ordinary skill in the art.” KSR Int’l Co. v. Teleflex, Inc., 550 U.S. 398, Appeal 2012-004203 Reexamination Control 95/000,483 & 90/009,482 Patent US 6,815,321 B2 13 420 (2007). “Under the correct analysis, any need or problem known in the field of endeavor at the time of invention and addressed by the patent can provide a reason for combining the elements in the manner claimed.” Id. Section 103(a) -- Oikawa and “Result Effective Variable” Owner argues in response to the § 103(a) rejection over Oikawa that the Examiner has failed to establish that the “width difference” of the metal layers represents a “result-effective variable” that was recognized in the prior art. App. Br. 25-27. However, at the oral hearing Owner’s counsel acknowledged that it was known to adjust the widths for step coverage but argued that the disclosure of the '321 patent taught a different reason to adjust the widths. [MR. BREGMAN:] So before we continue, what’s the Examiner talking about here with this unexpected result? So he’s saying that -- sorry, with the result-effective variable. He’s saying that everyone in the art knew that you could just adjust this variable width to address the hillock problem. Well, that's simply not true. There’s not a single reference in the record that discusses that you could adjust the width, the variable width, to affect or to address the hillock problem. People adjust the width for other reasons -- for step coverage, for various other reasons -- but certainly no one appreciated that you would adjust these variable widths to deal with hillocks. JUDGE MACDONALD: Now what reason did the Examiner says it was being adjusted? Did they pick a particular one? MR. BREGMAN: Well, he was saying that people would have known to adjust the range because of step coverage, which was known, but who’s to say which optimum range? Appeal 2012-004203 Reexamination Control 95/000,483 & 90/009,482 Patent US 6,815,321 B2 14 That’s not the result-effective variable to avoid hillocks. That's a result-effective variable to address some other issue. JUDGE MACDONALD: But is that really relevant given KSR? MR. BREGMAN: In what way, Your Honor? JUDGE MACDONALD: In that he would arrive at this particular structure for other reasons. MR. BREGMAN: You see, I don't think you would arrive at the structure because the result-effective variable for adjusting the variable widths for step coverage could be a completely different range. I mean, it's not the range that's being optimized to address the hillock problem. It could be bigger than four micrometers. It could be smaller than one. JUDGE MACDONALD: Yes, but you just said it’s not the range. MR. BREGMAN: Well, no one appreciated that if you found this difference in widths between one and four that you could avoid hillocks. No one appreciated that. They said you could have a different step, but that’s for step coverage purposes. Hearing Trans. 21-23. However, Owner’s contention that a range for optimal step coverage is different than that for preventing hillock formation is contrary to the '321 patent’s disclosure. The present inventors have discovered that a relationship between the width of the first metal layer and the width of the second metal layer of a double metal layer gate electrode is critical to preventing deterioration of step coverage of a later formed gate oxide layer in such a structure having a double step Appeal 2012-004203 Reexamination Control 95/000,483 & 90/009,482 Patent US 6,815,321 B2 15 difference between the substrate and the gate. More specifically, the present inventors determined that a structure wherein the first metal layer 43 is wider than the second metal layer 45 by about 1 to 4 µm, for example, 1 µmCopy with citationCopy as parenthetical citation