Power Integrations v. Fairchild Semiconductor

• Decision Date: 31 March 2006
• Docket Number: No. C.A. 04-1371-JJF.,C.A. 04-1371-JJF.
• Citation: 422 F.Supp.2d 446
• Parties: POWER INTEGRATIONS, INC., a Delaware corporation, Plaintiff, v. FAIRCHILD SEMICONDUCTOR ITERNATIONAL, INC., a Delaware corporation, and Fairchild Semiconductor Corporation, a Delaware corporation, Defendants.
• Court: U.S. District Court — District of Delaware

Page 446

422 F.Supp.2d 446

POWER INTEGRATIONS, INC., a Delaware corporation, Plaintiff, v. FAIRCHILD SEMICONDUCTOR ITERNATIONAL, INC., a Delaware corporation, and Fairchild Semiconductor Corporation, a Delaware corporation, Defendants.

No. C.A. 04-1371-JJF.

United States District Court, D. Delaware.

March 31, 2006.

William J. Marsden, Jr., and Sean P. Hayes, of Fish & Richardson P.C., Wilmington, Delaware, Frank E. Scherkenbach, of Fish & Richardson P.C., Boston, Massachusetts, Howard G. Pollack, and Michael R. Headley, of Fish & Richardson P.C., Redwood City, California. for Plaintiff, of counsel.

Steven J. Balick, and John G. Day, of Ashby & Geddes, Wilmington, Delaware, G. Hopkins Guy, III, Vickie L. Freeman, Bas de Blank, and Brian H. VanderZanden, of Orrick, Herrington & Sutcliffe LLP, Menlo Park, California, for Defendants, of counsel.

MEMORANDUM OPINION

FARNAN, District Judge.

This action was brought by Plaintiff, Power Integrations, Inc. ("Power Integrations") against Defendants Fairchild Semiconductor International, Inc. and Fairchild Semiconductor Corporation (collectively "Fairchild") alleging willful infringement of United States Patent Nos. 4,811,075 (the "'075 patent"), 6,107,851 (the "'851 patent"), 6,229,366 (the "'366 patent"), 6,249,876 (the "'876 patent"). The parties briefed their respective positions on claim construction, and the Court conducted a Markman hearing on the disputed terms in the asserted patents. This Memorandum Opinion presents the Court's construction of the disputed terms.

BACKGROUND

The patents-in-suit generally relate to integrated circuit devices used in power supplies and can be broken down into two categories. The first type of technology which is exemplified in the '075 patent relates to the physical structure of a high voltage metal-oxide semiconductor ("MOS") transistor device. The MOS transistor device described in the '075 patent incorporates a top layer, referred to as the "p-top layer," in the "extended drain region" of the device. This technology seeks to provide more efficient high voltage MOS transistors and improved ability to incorporate the high voltage structure into a device having low-voltage circuits on the same integrated circuit chip. According to Power Integrations the technology of the '075 patent created the basis for Power Integrations to form as a company and allowed Power Integrations to provide the first commercially viable, "fully integrated" integrated circuit device for use in controlling switch mode power supplies.

The second type of technology is exemplified in the '366, '851 and '876 patents (collectively referred to as the "circuit patents") and relates to the circuit design associated with the integrated power supply controllers made by Power Integrations. The circuit patents relate to circuit structures within the integrated circuit devices that provide functions which are useful to the overall power supply design into which the chips are incorporated. The circuit patents specifically relate to two types of functions, "frequency jitter" and "integrated soft start." According to Power Integrations, the frequency jitter technology allows power supply designers to reduce peak electromagnetic interference ("EMI") so that electronic products can meet government standards set for EMI using smaller, less complicated and less expensive components than that which was available in the prior art. The integrated soft start technology seeks to solve problems associated with starting up a power supply, including limiting the inrush of currents at start up.

DISCUSSION

I. The Legal Principles of Claim Construction

Claim construction is a question of law. Markman v. Westview Instruments, Inc., 52 F.3d 967, 977-78 (Fed.Cir. 1995), aff'd, 517 U.S. 370, 388-90, 116 S.Ct. 1384, 134 L.Ed.2d 577 (1996). When construing the claims of a patent, a court considers the literal language of the claim, the patent specification and the prosecution history. Markman, 52 F.3d at 979. Of these sources, the specification is considered the single best guide for discerning the meaning of a claim. Phillips v. AWH Corporation, 415 F.3d 1303, 1312-1317 (Fed.Cir.2005).

A court may consider extrinsic evidence, including expert and inventor testimony, dictionaries, and learned treatises, in order to assist it in understanding the underlying technology, the meaning of terms to one skilled in the art and how the invention works. Phillips, 415 F.3d at 1318-19; Markman, 52 F.3d at 979-80 (citations omitted). However, extrinsic evidence is considered less reliable and less useful in claim construction than the patent and its prosecution history. Phillips, 415 F.3d at 1318-19 (discussing "flaws" inherent in extrinsic evidence and noting that extrinsic evidence "is unlikely to result in a reliable interpretation of a patent claim scope unless considered in the context of intrinsic evidence").

In addition to these fundamental claim construction principles, a court should also interpret the language in a claim by applying the ordinary and accustomed meaning of the words in the claim. Envirotech Corp. v. Al George, Inc., 730 F.2d 753, 759 (Fed.Cir.1984). If the patent inventor clearly supplies a different meaning; however, then the claim should be interpreted according to the meaning supplied by the inventor. Markman, 52 F.3d at 980 (noting that patentee is free to be his own lexicographer, but emphasizing that any special definitions given to words must be clearly set forth in patent). If possible, claims should be construed to uphold validity. In re Yamamoto, 740 F.2d 1569, 1571 & n. * (Fed.Cir.1984) (citations omitted).

II. The Meaning Of The Disputed Terms of the Asserted Patents

A. The Disputed Terms In The '075 Patent

All the disputed terms of the '075 patent are contained in independent claim 1 of the '075 patent. In full, claim 1 of the '075 patent recites:

1. A high voltage MOS transistor comprising:

a semiconductor substrate of a first conductivity type having a surface;

a pair of laterally spaced pockets of semiconductor material of a second conductivity type within the substrate and adjoining the substrate surface,

a source contact connected to one pocket,

a drain contact connected to the other pocket,

an extended drain region of the second conductivity type extending laterally each way from the drain contact pocket to surface-adjoining positions,

a surface adjoining layer of material of the first conductivity type on top of an intermediate portion of the extended drain region between the drain contact pocket and the surface adjoining positions,

said top layer of material and said substrate being subject to application of a reverse-bias voltage,

an insulating layer on the surface of the substrate and covering at least that portion between the source contact pocket and the nearest surface adjoining position of the extended drain region, and

a gate electrode on the insulating layer and electronically isolated form the substrate region thereunder which forms a channel laterally between the source contact pocket and the nearest surface-adjoining position of the extended drain region, said gate electrode controlling by field-effect the flow of current thereunder through the channel.

('075 patent, col. 6, 11. 54—col. 7, 11, 12).

1. DMOS

A central part of the parties' dispute focuses on the meaning of the term "DMOS." Although this term is not found in the asserted claims of the '075 patent, Fairchild contends that the construction of this term is important, because Power Integrations disclaimed DMOS structures during the prosecution of the '075 patent.

In its Opening Claim Construction Brief, Fairchild contends that "DMOS" means "double-diffused MOS." In its Answering Claim Construction Brief, Fairchild elaborates that DMOS means "a MOS structure in which the source pocket is formed entirely within a channel region of more heavily doped semiconductor material (commonly referred to as a "body" region) that is formed within the substrate." (D.I. 166 at 5). Fairchild further contends that the term "DMOS" is not restricted to any particular process for making the DMOS structure.

In response, `Power Integrations acknowledges the importance of the construction of the term "DMOS" to Fairchild's arguments, but contends that this term should not be defined by the Court in the context of claim construction because the term "DMOS" is not found anywhere in the '075 patent. According to Power Integrations the DMOS issue pertains to equivalence and estoppel arguments. (D.I. 164 at 2). Power Integrations urges the Court to decline from importing a DMOS limitation into the terms of the '075 patent and requests the Court to defer ruling on whether the scope of the disclaimer made by Power Integrations during the prosecution of the patent has any impact on this case.

In the alternative, Power Integrations contends that the Court should construe the term "DMOS" to mean "a device formed by successive diffusions of different materials through the same opening in an insulating or mask layer." (D.I. 152 at 27). Power Integrations goes on to explain more specifically, that the double diffusion process was used to form the channel and source contact regions of the transistor by successively diffusing material made of different conductivity types. According to Power Integrations, it was important that this diffusing process was done through the same opening in the insulated layer to allow the edges of the different regions to be controlled with precision, a process known as self-aligning. The result of this process is a transistor with a very short channel length which could be accurately controlled. Power Integrations contends that the term "DMOS" has been broadened since the time of the prosecution of the '075 patent to encompass all electrically asymmetrical transistors including those whose characteristics of the channel region are determined by a separate diffusion...