International Rectifier Corp. v. Ixys Corp.

• Decision Date: 18 March 2004
• Docket Number: No. 02-1414.,No. 02-1554.,02-1414.,02-1554.
• Citation: 361 F.3d 1363
• Parties: INTERNATIONAL RECTIFIER CORPORATION, Plaintiff-Cross Appellant, v. IXYS CORPORATION, Defendant-Appellant.
• Court: U.S. Court of Appeals — Federal Circuit

361 F.3d 1363

INTERNATIONAL RECTIFIER CORPORATION, Plaintiff-Cross Appellant, v. IXYS CORPORATION, Defendant-Appellant.

No. 02-1414.

No. 02-1554.

United States Court of Appeals, Federal Circuit.

March 18, 2004.

Rehearing Denied April 29, 2004.

COPYRIGHT MATERIAL OMITTED

David E. Killough, Vinson & Elkins L.L.P., of Austin, TX, argued for plaintiff-cross appellant. Of counsel on the brief was Glenn W. Trost, Coudert Brothers LLP, of Los Angeles, CA.

Roger L. Cook, Townsend & Townsend and Crew LLP, of San Francisco, CA, argued for defendant-appellant. With him on the brief were R. Scott Wales and Nancy L. Tompkins.

Before NEWMAN, LINN, and PROST, Circuit Judges.

LINN, Circuit Judge.

IXYS Corporation ("IXYS") appeals from a final judgment of the United States District Court for the Central District of California concluding, pursuant to a series of stipulations and motions for summary adjudication, that IXYS infringed various claims of U.S. Patents Nos. 4,959,699 ("the '699 patent"), 5,008,725 ("the '725 patent"), and 5,130,767 ("the '767 patent"), owned by International Rectifier Corporation ("IR").¹ Int'l Rectifier Corp. v. IXYS Corp., No. CV-00-6756-R (C.D.Cal. July 1, 2002) ("Final Judgment"). IXYS also appeals from orders of the district court granting IR's motion for summary adjudication of IXYS's affirmative defenses of estoppel and laches, Int'l Rectifier Corp. v. IXYS Corp., No. CV-00-6756-R (C.D.Cal. Apr. 1, 2002) ("Equitable Defenses Order"), and derivation and inequitable conduct, Int'l Rectifier Corp. v. IXYS Corp., No. CV-00-6756-R (C.D.Cal. Dec. 17, 2001) ("Derivation Order"). Finally, IXYS requests that, if remand is necessary, this case be reassigned to a different district court judge.

Because IXYS's allegations of derivation and inequitable conduct, even if taken as uncontroverted, are insufficient as a matter of law, we affirm the district court's Derivation Order. However, because the district court's Equitable Defenses Order was based solely on IXYS's invocation of privilege, and because IXYS has set forth other, non-privileged evidence in support of the defenses of laches and estoppel, we vacate the order and remand to the district court for consideration of IXYS's defenses in light of the non-privileged evidence. Because we hold that the district court's construction of the term "adjoining" as used in claims 19, 22, 24, and 27 of the '699 patent was erroneous, and because no reasonable jury could find those claims infringed based on the facts stipulated to by the parties, we reverse the district court's denial of IXYS's motion for summary judgment of non-infringement of claims 19, 22, 24, and 27 of the '699 patent and reverse-in-part the district court's Final Judgment with respect to those claims. Because the district court also erred in construing the claim terms "polygonal" and "annular," and because genuine issues of material fact remain with respect to the asserted claims containing those terms, we vacate-in-part the portion of the district court's Final Judgment relating thereto and remand the case to the original district court judge for further proceedings consistent with this opinion.

BACKGROUND

The patents-in-suit relate to vertical planar power metal-oxide-semiconductor (VPPM) transistor devices, such as metal-oxide-semiconductor field effect transistors (MOSFETs) and insulated gate bipolar transistors (IGBTs). These devices are used to switch line-level electric voltages on and off at high speeds. Like other semiconductor devices, the transistors at issue here are manufactured, in part, by implanting a pattern of impurities (such as boron) into the surface of a silicon semiconductor wafer. The impurities are introduced through a window in an "implant mask," used to define the pattern of the implant on the surface of the silicon. After implantation, the wafer is heated at a high temperature to cause the impurities to diffuse in three dimensions outwards from the surface and into the wafer. The shape of each region of the resulting transistor is determined by the shape of the mask, the temperature and duration of the diffusion heating, and the concentration of the impurities used.

NOTE: OPINION CONTAINING TABLE OR OTHER DATA THAT IS NOT VIEWABLE

The written descriptions and drawings of the '725 and '767 patents are identical. Figure 3 of the patents is reproduced above to illustrate the discussion that follows. "By using suitable masks, a plurality of P type base regions such as regions 22 and 23 in [Figure 3] are formed in one surface of the semiconductor wafer region 21, where these regions are generally polygonal in configuration and, preferably, are hexagonal." '725 patent, col. 2, l. 65 — col. 3, l. 2. Each of the "polygonal" regions, such as base regions 22 and 23, are surrounded by "polygonal ring" source regions 26 and 27, respectively. Id., col. 3, ll. 20-22.

The claims at issue in this appeal pertain to these regions and their shapes. Claims 1 and 19 of the '699 patent are representative. Claim 1 recites, in relevant part and with the disputed terms underlined:

1. A high power metal oxide silicon field effect transistor device exhibiting relatively low on-resistance and relatively high breakdown voltage; said device comprising:

a wafer of semiconductor material having first and second opposing semiconductor surfaces; said wafer of semiconductor material having a relatively lightly doped major body portion for receiving junctions and being doped with impurities of one conductivity type;

at least first and second spaced base regions of the opposite conductivity type to said one conductivity type ...

first and second source regions of said one conductivity type ...

at least said first base region being a cellular polygonal region; said cellular polygonal region being surrounded by said common conduction region; said first source region having the shape of an annular ring disposed within said cellular polygonal first base region.

'699 patent, Reexamination Certificate Issued Under 35 U.S.C. § 307, B2 4,959,699, col. 1, l. 25 — col. 2, l. 5.

Claim 19 of the '699 patent recites, with the disputed term underlined:

19. A high power metal oxide silicon field effect transistor device exhibiting relatively low on-resistance; said device comprising:

a wafer of semiconductor material having first and second opposing semiconductor surfaces; said wafer of semiconductor material having a relatively lightly doped major body portion for receiving junctions and being doped with impurities of one conductivity type;

at least first and second spaced base regions of the opposite conductivity type to said one conductivity type formed in said wafer ...

said wafer including a further region of opposite conductivity type adjoining said lightly doped major body portion; and

an electrode coupled to said further region.

Id., col. 3, l.6 — col. 4, l. 9.

The technology of these power transistors traces its origins to work done in the late 1970s. In 1975, Hewlett-Packard ("HP") began a new research initiative to develop a semiconductor chip that was capable of fast switching and of withstanding a power surge of 450 volts, about double the wall voltages ordinarily found in Europe and well in excess of the lower voltages found in the United States. This research resulted in the first VPPM device prototype chip. To optimize the prototype chip for commercial production, Dr. Nathan Zommer, founder and current CEO of IXYS, was employed by HP in 1977. Also at HP during this period was Joseph Berger, an engineer, who in the summer of 1977 shared some of HP's developments with Dr. James Plummer, a professor in the Electrical Engineering department at Stanford University.

Dr. Plummer's graduate students did further work advancing the VPPM concept that the HP engineers had developed. Between July and December 1977, Ernie Wood, a Stanford Ph.D. candidate, openly fabricated and tested a new VPPM device in Dr. Plummer's lab (the "Plummer/Wood device"). Wood worked extensively with Dr. John Shott, another member of the Stanford laboratory. Also in the lab with Wood, but working on unrelated projects, was another doctoral student, Alexander Lidow. Wood testified that although he did not recall discussing the Plummer/Wood device with Lidow, the two knew one another and "hung out" together. Wood also testified that he discussed the things he was working on with anyone "that wasn't bored stiff."

Lidow graduated in December 1977 to take a job with IR, a company his father had founded in 1947. IR was interested in producing a commercially viable high-power switching device. Following a brief discussion with Tom Herman, a colleague at IR, and after further discussions with Drs. Shott and Plummer, Lidow developed a basic sketch for such a device. An initial prototype of this device worked well and eventually led to the '699 patent. The Plummer/Wood device was not disclosed to the United States Patent and Trademark Office ("Patent Office") during the prosecution of the '699 patent. On September 25, 1990, the Patent Office issued the '699 patent to Lidow and Herman. The applications resulting in the '725 and '767 patents, which are not related to the '699 patent but are related to each other via continuation, are directed to similar technology and incorporate the '699 patent by reference. All three patents are assigned to IR.

Several times between 1987 and 1996, IR accused IXYS of infringing its VPPM patents and requested IXYS to take a royalty-bearing license. IXYS refused on the belief that its technology was fundamentally different from that of IR's patents. After another refusal to take a license in 1996, IR and IXYS discussed the possibility of a merger; this merger never occurred.

Between 1996 and 2000, IR asserted its patents against a number of major competitors in the semiconductor field, including Samsung Semiconductor, Inc. and Samsung Electronics Co., Ltd. (collectively "Samsung")...