Opinion ID: 787299
Heading Depth: 3
Heading Rank: 1

Heading: Claim Construction of Contacting ... to Form [an] Interface

Text: 41 We begin our discussion with the requirements present in both independent claims 11 and 14 of a contact layer contacting with all the first and second semiconductor regions to form [an] interface. '275 patent, col. 8, ll. 2-5. The district court found that the second interface was not formed in either Infineon's or ST's device because the alternating semiconductor regions in the voltage sustaining layer did not physically touch the second contact layer. Power Mosfet Techs., slip op. at 38, 78. PMT challenges this conclusion on two fronts. First, PMT challenges the claim construction directly, disputing the district court's physical contact requirement. Second, PMT argues that the district court's conclusion of noninfringement is based on a changed construction of the term contacting, from permitting either electrical or physical contact as construed by the Special Master at the Markman hearing and subsequently adopted by the district court, to requiring physical contact in the district court's final decision. To correct the error, PMT argues, the claims should be returned to the original interpretation attributed to them by the Special Master and district court, which, according to PMT, permitted satisfaction of the claim limitations without physical contact between the CB-layer and the contact layer. ST and Infineon both respond that there has been no change in claim construction and that what PMT actually disagrees with is the factual infringement determination by the district court. 42 As explained, the Special Master interpreted contacting functionally as permitting either electrical or physical contact. Special Master Report at 26. The Special Master's construction of interface, however, explained that the term, as used in the '275 patent, was necessarily physical. Id. at 37. PMT does not challenge the Special Master's construction of the individual terms contacting or interface, and we see no basis in the patent specification for disturbing them. In fact, PMT explained during a hearing following the Special Master's recommendations that it believe[d] that the Special Master correctly construed the term interface, and [it was] happy with the construction of the term interface. (J.A. at 203017). When the Special Master's interpretations are inserted into the claims as a whole, however, we agree with the district court that the alternating semiconductor regions must physically touch the contact layer. It is with this result that PMT disagrees. 43 Working with the Special Master's definitions, as it must after expressly agreeing with them, PMT attempts to explain how the common boundary requirement of interface and the electrical or physical definition of contacting can coexist when the claims are read as a whole. The interface, according to PMT, is present in the physical boundary between the voltage sustaining layer (here, the n-buffer layer) and the contact layer. The contacting requirement is also satisfied, PMT continues, by the electrical conduction that occurs between the CB-layer and the contact layer. Thus, according to PMT, both claim requirements may be satisfied without physical contact between the alternating semiconductor regions and the contact layer. 44 PMT's urged claim construction relies heavily on statements made in the Special Master Report explaining that the term is used throughout the claims to mean the common boundary between the `contact layer' and the `voltage sustaining layer.' Special Master Report at 36 (citing the '275 patent, col. 7, l. 68 to col. 8, l. 5); see also id. at 36-37 (Nevertheless, in the Chen patent, this interface is necessarily physical because it is a junction between two semiconductor layers, the contact layer and the voltage sustaining layer.). PMT seizes upon the above descriptions of the interface to support its position that, regardless of what comprises the voltage sustaining layer, the required interface will always be between it and the contact layer. According to PMT, no interface is required between the CB-layer and the contact layer. 45 This, however, is not how we read the claims or the Special Master's recommended construction of their terms. The Special Master appears to have been using voltage sustaining layer interchangeably with CB-layer in his discussion, as evidenced by his citations to the patent. For example, in the quotation set out above, the Special Master cites the '275 patent at column 7, line 68, to column 8, line 5, which is the language from claim 11 at issue (i.e., contacting with all the first and second semiconductor regions to form [an] interface). As we read the cited passage, the language specifically locates the interface between the contact layer and the alternating semiconductor regions of the CB-layer, not an undefined voltage sustaining layer. The Special Master further explained that [g]iven the overall structure of the Chen MOS devices, [the contact and voltage sustaining] layers will touch each other, and cited a passage from the '275 patent describing the manufacture of the CB-layer on the surface of the contact layer. See Special Master Report at 36 (citing the '275 patent, col. 5, ll. 52-58). 46 While the Special Master correctly acknowledged that the voltage sustaining layer was open to additional elements and layers due to the comprising term, Special Master Report at 32, his discussion of the interface is understandably confined to the structure actually described by the '275 patent. See SRI Int'l v. Matsushita Elec. Corp., 775 F.2d 1107, 1118 (Fed.Cir.1985) (en banc) (A claim is construed in the light of the claim language, the other claims, the prior art, the prosecution history, and the specification, not in light of the accused device.). Furthermore, because he did not attempt to construe the claims as a whole, the Special Master had no opportunity to reconcile the functional definition he adopted for contacting with his structural interpretation of interface. The district court, however, could not avoid the necessary reconciliation, and concluded that, when the Special Master's construction of the individual terms are plugged into the remaining claim language, the claims require the interface to be between the alternating semiconductor regions of the CB-layer and the contact layer. Power Mosfet Techs., slip op. at 36-39, 78-79. We agree with the district court's conclusion. While the contacting requirement may be satisfied with either physical or electrical contact, we do not see how electrical contact alone can form the necessarily physical junction required for the interface. Comprising, while permitting additional elements not required by a claim, does not remove the limitations that are present. See W.E. Hall v. Atlanta Corrugating, LLC, 370 F.3d 1343, 1353 (Fed.Cir.2004) (explaining that each and every limitation of a claim must be satisfied before additional elements are examined under the partially open term consisting essentially of). 47 The written description lends additional support to this interpretation. The main discussion of the fabrication process in the '275 patent describes: (1) Epitaxial growth of an n - (or p -)-layer 5 on the n + (or p +)-substrate 4; (2) Selective trenching on 5 to make very deep U-grooves, where the bottoms of the grooves just reach 4 .... '275 patent, col. 5, ll. 32-35 (emphasis added); see also id. at col. 5, ll. 52-55 (detailing the growth of an epi-layer  on the n + (or p +)-substrate (i.e., the contact layer), to create a CB-layer according to the method described above (emphasis added)); id. at col. 2, ll. 1-4 (describing the arrangement of n- and p-regions when viewed from any cross-section parallel to the interface between the CB-layer itself and the n +-region). Each of the figures in the '275 patent depicts physical contact between the CB-layer and the contact layer and, where an intervening layer is permitted, the written description expressly provides for it. See id. at col. 6, ll. 37-39 (From FIG. 4 to FIG. 9 the existence of dielectric films between 4 [the first contact layer] and 7 [the second semiconductor region], and/or between 6 [the first semiconductor region] and 7, if any, are allowed.). To accommodate the interleaved dielectric film described by the written description, claim 1 of the '275 patent omits the requirement of an interface between the first contact layer and the second semiconductor region. Id. at col. 6, ll. 41-60. 48 The term directly, which appears in two of the three independent claims of the '275 patent, does not affect our conclusion. Claim 1 requires a second contact layer contacting the first and second semiconductor regions directly forming a second interface. Id. at col. 6, ll. 58-60 (emphasis added). Claim 14 has a similar requirement, also applying only to the second contact layer. Id. at col. 8, ll. 38-40. Claim 11, however, has no directly limitation, nor does the term append the first interface requirement in any of the claims. PMT states on appeal that this term is meaningless, while Infineon argues that contacting ... directly means physically touching. Although he noted the argument, the Special Master did not address the issue. Special Master Report, slip op. at 24. The district court likewise did not specifically address the term, but, in light of its conclusion that contacting ... to form an interface required physical contact, the import of directly was irrelevant. 49 While we have often explained that we presume that there is `a difference in meaning and scope when different words or phrases are used in separate claims,' the rule is not inflexible. Comark Communications. v. Harris Corp., 156 F.3d 1182, 1187 (Fed.Cir.1998) (quoting Tandon Corp. v. U.S. Int'l Trade Comm'n, 831 F.2d 1017, 1023 (Fed.Cir.1987)). Furthermore, while interpretations that render some portion of the claim language superfluous are disfavored, where neither the plain meaning nor the patent itself commands a difference in scope between two terms, they may be construed identically. See Pickholtz v. Rainbow Techs., Inc., 284 F.3d 1365, 1373 (Fed.Cir.2002). Here, the addition of the term directly to an existing requirement of physical contact imposes no additional restrictions on the phrase. Whether the alternating semiconductor contact [s] ... directly to form a second interface, or merely contact[s] ... to form a second interface, a physical boundary must be formed. 50 In affirming the district court's construction of contacting... to form [an] interface, we must also affirm the district court's ultimate determination that neither the Infineon nor the ST products literally infringe the '275 patent. The requirement is present in both of the independent claims asserted, and, as the district court found, is not met by either of the accused devices. Power Mosfet Techs., slip op. at 38-39, 78-79.