Ex Parte InoueDownload PDFBoard of Patent Appeals and InterferencesMay 31, 200510095053 (B.P.A.I. May. 31, 2005) Copy Citation The opinion in support of the decision being entered today was not written for publication and is not binding precedent of the Board. UNITED STATES PATENT AND TRADEMARK OFFICE _____________ BEFORE THE BOARD OF PATENT APPEALS AND INTERFERENCES _____________ Ex parte MASAO INOUE _____________ Appeal No. 2005-1065 Application No. 10/095,053 ______________ ON BRIEF _______________ Before CAROFF, PAK and KRATZ, Administrative Patent Judges. CAROFF, Administrative Patent Judge. DECISION ON APPEAL This decision on appeal relates to appellant’s claims 1-5 which have been thrice-rejected by the examiner. Claims 6-8, all the other claims in appellant’s involved application, stand withdrawn from consideration pursuant to the provisions of 37 CFR § 1.142(b) and, thus, are not before us. The claims on appeal are directed to a method of manufacturing a semiconductor device whereby a gate oxide film is formed on the surface of a semiconductor substrate. According to Appeal No. 2005-1065 Application No. 10/095,053 1We note in passing that appellant’s brief and reply brief erroneously state that it is the oxidation preventive film, rather that the gate oxide film, which is subject to thinning. This is clearly not the case, as thoroughly discussed in appellant’s specification. 2 appellant’s specification (p. 2, l. 24-p. 3, l. 22), the claimed method provides a gate oxide film of uniform thickness where the thickness directly above an oxidation preventive film at the top edge of a trench structure is of the same order as the thickness of the gate oxide film at other locations along the surface of the semiconductor substrate. This is said to solve a so-called “thinning” problem experienced in the prior art.1 Appellant’s brief (page 4) stipulates that the appealed claims stand or fall together with independent claim 1. Accordingly, we shall limit our consideration to claim 1 which reads as follows: 1. A method of manufacturing a semiconductor device comprising: a step of forming a trench at a main surface of a semiconductor substrate; the step of forming an oxidation preventive film along an inner wall of said trench; the step of forming a filling layer so as to fill said trench; and Appeal No. 2005-1065 Application No. 10/095,053 3 the step of applying an high oxidation capability on said main surface of a semiconductor substrate in an atmosphere in which radicals of at least one kind of hydrogen radicals and oxygen radicals are generated to thereby form a gate oxide film on said main surface of a semiconductor substrate and to oxidize an upper surface of the oxidation preventive film such that oxidizing speeds on the oxidation preventive film and the semiconductor substrate are substantially the same as each other. The prior art references relied upon by the examiner are: Admitted Prior Art on pages 1-2 of the instant application. Toru 10-313114 Nov. 24, 1998 (Published Japanese Patent Application) Atkins et al. (Atkins), Chemical Principles, pp. 71-2 (W.H. Freeman and Co., 1999). Wolf, Silicon Processing For The VLSI Era, Vol. 3: The Submicron Mosfet, p. 334 (Sunset Beach, CA, Lattice Press, 1995). All of the appealed claims stand rejected for obviousness under 35 U.S.C. § 103(a). To support the rejection of claims 1-2 and 5, the examiner relies upon the admitted prior art in view of Toru and Atkins. Claims 3-4 stand rejected on the same basis with additional reliance upon Wolf. Based upon the record before us, we find that the examiner has failed to establish a prima facie case of obviousness. Accordingly, we shall reverse each of the rejections at issue. Appeal No. 2005-1065 Application No. 10/095,053 4 As we see it, the examiner’s position is predicated upon the doctrine of inherency. To wit, in accordance with the examiner’s reasoning, the conventional technique for forming a gate oxide film by oxidation involves use of oxygen gas (acknowledged prior art), and Atkins teaches that oxygen, either in its atomic or molecular form, is considered to be a radical; more specifically a biradical. Thus, as stated in the examiner’s answer (pages 10- 11), since the materials and manipulative steps involved in appellant’s claimed invention appear to be identical to those embodied in the prior art, the same result must necessarily occur. That is to say, when the prior art technique is performed, the upper surface of the oxidation preventive film and the semiconductor substrate must be oxidized at substantially the same speed, as in appellant’s invention. The examiner’s rationale is in line with the body of case law on inherency exemplified by In re Best, 652 F.2d 1252, 1255, 195 USPQ 430, 433-34 (CCPA 1977). Although there is great force of logic in the examiner’s position, we nevertheless find that there is no question of inherency here. Appeal No. 2005-1065 Application No. 10/095,053 5 In our opinion, claim 1 must be read in light of the specification (p. 7, ll. 4-13) to give meaning and vitality to the expression “applying an high oxidation capability.” In so doing, we take the expression to mean: . . . [H]ydrogen gas and oxygen gas are separately introduced into a reaction vessel accommodating wafers to react with each other directly above the wafers and thereby generate hydrogen radicals and oxygen radicals, which generates oxidation with a high capability. [Underlining added for emphasis.] Clearly, when the claim language is so interpreted, there is no question of inherency since neither the admitted prior art alone, or in combination with any of the other cited references, teaches or suggests generating hydrogen radicals and oxygen radicals by separately introducing hydrogen gas and oxygen gas into a reaction vessel to react with each other directly above wafers in the vessel to obtain a gate oxide film of uniform thickness, viz., to oxidize the upper surface of a oxidation preventive film and the upper surface of a semiconductor substrate at substantially the same speed. Appeal No. 2005-1065 Application No. 10/095,053 6 In fact, according to appellant’s specification (p. 2, ll. 12-16), in the prior art the oxidation necessary to form a gate oxide film is effected by introducing hydrogen gas and oxygen gas into a reaction vessel accommodating wafers after the gases react with each other, or introducing only oxygen gas into the vessel. For the foregoing reasons, the decision of the examiner is reversed. REVERSED MARC L. CAROFF ) Administrative Patent Judge ) ) ) ) BOARD OF PATENT CHUNG K. PAK ) APPEALS AND Administrative Patent Judge ) INTERFERENCES ) ) ) PETER F. KRATZ ) Administrative Patent Judge ) MLC:hh Appeal No. 2005-1065 Application No. 10/095,053 7 MCDERMOTT, WILL & EMERY 600 13TH ST., N.W. WASHINGTON, D.C. 20005-3096 Copy with citationCopy as parenthetical citation