The opinion of the court was delivered by: SMITH
Pending before the Court is the parties' dispute about the proper construction of three patents that relate to the production and design of computer memory chips, called EEPROMs, that are programmable, electrically erasable, and non-volatile. These chips are useful in applications, such as programmable car radios, in which it is advantageous to enable the device to be programmed by the user, but to retain its information when power to the device is disconnected. Two of the patents at issue, patent number 4,822,750 ("the '750 patent") and patent number 4,701,776 ("the '776 patent") respectively, describe a process for manufacturing and a particular physical embodiment of such chips. These patents spring from a single application;
although they have different claim language, they retain identical specifications that describe both the process and the device.
Programming EEPROMs requires higher voltages than are normally supplied to chips. The third patent, number 4,511,811 ("the '811 patent"), describes a combination of electrical circuits that enables programming voltages to be generated on the chip instead of supplied from an external high-voltage source, an innovation that saves space and allows the devices to be manufactured more cheaply.
In June 1995, plaintiff filed a complaint in federal court alleging that defendant was infringing these patents. The Court held two tutorials, conducted off the record, in late 1996 and 1997, in order to understand the technology underlying the patents. Briefing on the issue of claim construction began in October 1997. In November 1997, defendant filed a motion for summary judgment of indefiniteness, which it requested the Court consider simultaneously to the claim construction. The Court vacated the hearing on that indefiniteness motion, ruling that it would be more efficient to consider it after it had construed the claims. Defendant also moved to strike a portion of the declaration of plaintiff's counsel on the ground that it contained argument rather than fact; plaintiff moved to strike the declarations of defendant's experts on the ground that they contained argument and legal conclusions. The Court took these motions to strike under submission.
A Markman hearing was held January 12 and January 13, 1998, at which the Court heard limited expert testimony to clarify several ambiguous terms. Having considered the parties' extended briefs and the evidence and arguments presented at the hearing, the Court issues the following ruling.
I. Legal Standard for Claim Construction
The Court ordinarily determines the meaning and scope of a patent as a matter of law. See Markman v. Westview Instruments, Inc., 517 U.S. 370, 116 S. Ct. 1384, 1387, 134 L. Ed. 2d 577 (1996). In construing a patent, the Court considers three sources, known as intrinsic evidence: the claims, the specification, and the prosecution history.
See Unique Concepts, Inc. v. Brown, 939 F.2d 1558, 1561 (Fed. Cir. 1991). "Unless the specification or the file history indicates that the inventor intended otherwise, a claim term will be accorded its ordinary and accustomed meaning." Wolverine World Wide, Inc. v. Nike, Inc., 38 F.3d 1192, 1196 (Fed. Cir. 1994). The Court will refer to extrinsic evidence, such as expert and inventor testimony, dictionaries, and learned treatises, only if the claim terms are ambiguous and are not defined by the specification and prosecution history. See Vitronics Corp. v. Conceptronic, Inc., 90 F.3d 1576, 1584 (Fed. Cir. 1996).
It is generally improper to limit the scope of the claim to examples used in the specifications, see Electro Med. Sys. v. Cooper Life Sciences, 34 F.3d 1048, 1054 (Fed. Cir. 1994), although the Court may use the patent specification to ascertain the meaning of a claim. See Unique Concepts, Inc. v. Brown, 939 F.2d 1558, 1561-62 (Fed. Cir. 1991). Means-plus-function claims present a special case, however. When such a claim discloses a means for performing a function "without the recital of structure, material, or acts in support thereof, . . . such claim shall be construed to cover the corresponding structure, material, or acts disclosed in the specification and equivalents thereof."
35 U.S.C. § 112, P 6; see also Valmont Industries, Inc. v. Reinke Manufacturing Co., 983 F.2d 1039, 1042 (Fed. Cir. 1993).
Under a means-plus-function analysis, if the specification mentions specific alternative structures, those structures are included in the scope of the patent. See Serrano v. Telular Corp., 111 F.3d 1578, 1583 (Fed. Cir. 1997). A specification that merely mentions the possibility of alternative structures without specifically identifying them is not sufficient to expand the scope of the claim beyond the example used. See Fonar Corp. v. General Elec. Co., 107 F.3d 1543, 1551 (Fed. Cir.), cert. denied, 139 L. Ed. 2d 192, 118 S. Ct. 266 (1997).
B. Construction of Related Patents
Identical or "indisputably interchangeable" claim terms in patents that share a common ancestry should be construed consistently. See Abtox v. Exitron Corp., 122 F.3d 1019, amended 131 F.3d 1009, 1010 (Fed. Cir. 1997) ("gas-confining chamber" and "gas-tight confining chamber" were "indisputably interchangeable"); Jonsson v. Stanley Works, 903 F.2d 812 (Fed. Cir. 1990). Nothing in these cases, however, extends the rule to terms that are merely "similar" or "parallel," as defendant would have the Court hold.
Notwithstanding this special rule about identical or "indisputably interchangeable" claim terms, it is improper to use a portion of a parent's specification that relates solely to one child patent to construe directly a different child. See Abtox, 122 F.3d at 1027. In using prosecution history, "statements in the parent application must be confined to their proper context." Id. at 1026-27 (where parent application disclosed both microwave and radio frequency technology, it was error to import limitations relating to radio technology into a child patent solely relating to microwave technology).
II. Construction of the '776 Patent
At the time the '776 patent was issued in 1987 (the '750 patent was issued in 1989), EEPROMs were known in the prior art. See '776 patent, 1:16-2:32. The '776 patent describes an improved structure for such a device, which was intended to reduce the sensitivity of the chips to minor variations in the positions their component parts, enabling the chips to be successfully mass-produced in smaller sizes.
spaced apart first and second doped regions of a second conductivity type in said substrate, the substrate area between said first and second doped regions serving to establish a channel for said memory device;
field stop regions in said substrate having edges defining the sides of said channel for said memory device and for separating each of said memory cells from others of said memory cells in said array;
a third doped region of said second conductivity type in said substrate formed to a depth less than said first predetermined depth of said well structure in order to provide a source of charge carriers, a portion of said third region extending from said first doped region into said substrate area between said first and second doped regions to define the length of said channel, another portion of said third doped region extending appreciably under the edges of said field stop regions which define the sides of said channel;
an electrically isolated first conductive gate disposed above said substrate between said first and second doped regions;
a first insulating layer separating said first conductive gate from said channel in said substrate, said first insulating layer including a section formed over said third doped region to permit the passage of charge carriers between said third doped region and said first conductive gate, said section having a thickness which is less than the thickness of the remainder of said first insulating layer; and
a second conductive gate disposed above and insulated from said first conductive gate.
The patent requires that "another portion of said third doped region extend appreciably under the edges of said field stop regions which define the sides of said channel." Defendant argues that "appreciably under" requires that the third doped region be formed before the field stop regions. Defendant points out that the process portion of the specification states that "the third region . . . is defined and implanted . . . prior to defining the field oxide channel stop regions." '776 patent, 3:48-51. It is inappropriate, however, to limit a product patent to a manufacturing process described in the specification. See Stratoflex, Inc. v. Aeroquip Corp., 713 F.2d 1530, 1541 (Fed. Cir. 1983). Moreover, no reasonable person would believe that the ordinary meaning of "appreciably under" refers to a production process rather than a spatial relationship. The Court therefore will not adopt defendant's interpretation.
Plaintiff proposes that "appreciably under" means that the third doped region must extend "far enough under . . . so that the edges of the third doped region are not exposed to the thin portion of the first insulating layer." Joint Constr. Ex. B at 6. Defendant objects that this is a "functional" definition precluded by the holding in York Products, Inc. v. Central Tractor Farm & Family Center, 99 F.3d 1568, 1573 (Fed. Cir. 1996). The Court disagrees. In York Products, the Federal Circuit construed claim language that required that a ridge extend "for at least a substantial part of the entire height" of the sidewall of a pickup truck bed. Construing "substantial part" to mean "nearly the entire length of," the court refused to adopt a "functional definition" of the term "substantial," according to which the term would mean "only so [high] as necessary" to accomplish the function of the structure. 99 F.3d at 1572-73. Plaintiff's construction would be such a "functional definition" if, for example, it required that the doped region be "far enough under to prevent voltage breakdown." Instead, plaintiff's construction is purely spatial.
B. "sides of said channel" and "field stop regions"
The '776 patent requires "field stop regions in said substrate having edges defining the sides of said channel for said memory device and for separating each of said memory cells from others of said memory cells in said array."
One dispute about the field stop regions involves whether they must enclose all four edges of the memory cell, as defendant claims, or whether they must only define the sides of the cell and not necessarily the ends, as plaintiff claims. The word "sides" in the claim language might conceivable mean any edge (as in the phrase "a square has four sides") or might mean "side" as opposed to "end" (as in the phrase "the sides of a truck"). The specification uses the word "side" in the latter sense, suggesting that that is what is meant by the claim as well. See '776 patent, 5:14-15 ("memory cells may be separated . . . from one another at the channel ends . . . and at the channel sides . . . ."); Unique Concepts, Inc. v. Brown, 939 F.2d 1558, 1561-62 (Fed. Cir. 1991) (court may use specification to ascertain the meaning of the claim). The specification also describes groups of mirror cells with no "channel end field oxide regions . . . separating individual cells at the channel ends." '776 patent, 5:20-23. Defendant's proposed reading would make impossible such mirror cells. Despite defendant's contention to the contrary, plaintiff's construction of "sides" is consistent with the claim language requiring the field stop region separate "each cell" from "others" in the array. This language can be read to mean that the region must separate the cell from "some others," not from "all others." The specification of the '776 patent therefore strongly supports plaintiff's construction.
Defendant argues that the term "field stop regions" in the '776 patent should be construed consistently with the term "field oxide regions" in the '750 patent. See Abtox v. Exitron Corp., 122 F.3d 1019, amended 131 F.3d 1009 (Fed. Cir. 1997) (requiring consistent construction of "indisputably interchangeable" terms in patents with a common ancestor). With this argument, defendant seeks to import the requirement of the '750 patent that there be "four opposed field oxide regions." '750 patent, 12:53. The Court is not convinced that "field stop regions" and "field oxide regions" are indisputably interchangeable terms. Even if they were, Abtox would not require that device claimed in the '776 patent have four such regions as opposed to two. In Abtox, the Federal Circuit held that it was inconsistent to construe the singular term "gas-confining chamber" to mean "a single chamber" in one patent but "multiple chambers" in a related patent. See Abtox, 122 F.3d at 1022. Abtox would control the outcome here if both patents claimed a singular "region," and the parties were disputing whether a "region" encompassed four sub-regions or two subregions. The patents in this case, however, both describe multiple "regions." The fact that the patents happen to require different numbers of such regions does not mean that the term "regions" is being construed inconsistently. The Court therefore holds that the field stop regions in the '776 patent need only define the sides, and not necessarily the ends, of the memory cell.
Defendant's proposed construction, however, is too narrow. Defendant argues that the field stop region must include both the field oxide region and the channel oxide region described in the specification, and that those regions cannot reside within the "active device region" of the memory cell. Defendant has not explained why there must be either the particular field oxide or channel oxide regions described in the specification, so long as there is a region defining the channel sides and separating cells from other cells. To hold otherwise would be improperly to limit the device to the preferred embodiment described in the specification. Nor has defendant provided anything other than expert testimony as an explanation for why the claim language means that the field stop regions cannot encroach upon the "active region." Under Vitronics, in the absence of an ambiguity, this is not a permissible way to interpret the claim language.
The Court holds that the claim means neither more nor less than what it actually says. The patent requires that there must be field stop regions located in the substrate that define the channel sides and that completely separate cells from at least some other cells.
The parties dispute the scope of the term "memory cell." Defendant argues that the term refers only to a cell that has a single select device and a single memory device. Plaintiff argues that as used in the patent, a "memory cell" can also encompass a cell with repeating elements that share the use of common regions, and which may contain multiple select and memory devices. Plaintiff refers to such a cell as a "mirror cell," although as discussed below, the Court believes that the term "mirror cell" is used in the specification with a different meaning.
The specification contemplates the creation of mirror cells: "As will be readily understood by those skilled in the art, 'mirror' cells may be formed in order to facilitate the integration of many memory cells into an array." '776 patent, 5:16-19. The Court believes that the specification uses the term "mirror cell" not with plaintiff's meaning, but rather to refer to an individual memory cell containing only a single select and memory device that lacks channel end field stop regions on both ends and that shares a region with at least one other such cell. That definition of "mirror cell" is consistent with the specification's statement that if mirror cells are formed, "channel end field oxide regions 13 [sic]
will separate groups of mirror cells as is known in the art, rather than separating individual cells at the channel ends as shown in Fig. 1." '776 patent, 5:21. The description of the entire mirrored assemblage as a "group of mirror cells" rather than as a single "mirror cell" suggests that a mirror cell is an atomic unit, not a collection of cells.
The terms "individual cells" and "mirror cells" in the specification thus each appear to denote cells with only a single memory and select device, distinguished only by the presence or absence of channel end field stop regions. Moreover, the specification later states that the "the memory cell of the present invention . . . includes a single gate select device . . . [and] a floating gate memory device." '776 patent, 2:64-68.
The Court therefore holds that the term "memory cell" in the '776 patent refers to a cell with a single select and memory device.
D. "first doped region" and "second doped region"
The specification supports defendant's construction. The claim states that a portion of the third doped region must "extend from" the first doped region. "Extension from" describes physical contact. Figure 5 of the specification, an alternative embodiment, shows the third doped region (labeled as region 33) touching only the drain (region 18), not the source (region 16). If the claim were construed to allow the first doped region to be the source, then the specification would depict a device in which no portion of the third doped region "extended from" the first doped region, a device not covered by the claim language.
The same analysis holds true for the preferred embodiment, depicted in Figure 1 of the specification. Although that diagram shows portions of the third doped region touching both the source (region 16) and the drain (region 18), region 33b, the portion of the third doped region depicted as touching the source region, is described as optional, whereas region 33a, the region depicted as contacting the drain, is required. '776 patent, 10:6-9. If the optional portion is absent, and the claim were construed to allow the first doped region to be the source, then this preferred embodiment would also not be covered by the claim language because no portion of the third doped region would extend from the first doped region. It is "rarely, if ever, correct and would require highly persuasive evidentiary support" to construe a claim such that the preferred embodiment in the specification falls outside the scope of the patent. Vitronics, 90 F.3d at 1583.
Here, plaintiff's construction could exclude both the preferred and the alternative embodiments.
Plaintiff's argument in response is based on an amendment to the claim. The claim originally required "spaced apart doped source and drain regions . . . [and] a third doped region . . . electrically connected to said drain region." Hudson Decl. Ex. C at 27. During the proceedings before the patent office, the applicants amended the claim to read "spaced apart first and second doped regions . . . [and] a third doped region . . . extending from said first doped region." '776 patent, 12:51-65. The Court is not certain whether this amendment was made to broaden the claim or for some other purpose, such as to avoid confusion with the use of the term "source" to describe the third doped region as a source of charge carriers for the floating gate. The Court therefore finds that there is not the kind of "highly persuasive evidentiary support" required by Vitronics, and holds that the "first doped region" must be the drain, and the "second doped region," by extension, the source.
E. "above . . . [and] between"
The patent requires "an electrically isolated first conductive gate disposed above said substrate between said first and second doped regions." '776 patent, 13:3-5. Defendant argues the word "between" requires that the gate span the entire distance between the source and the drain. Plaintiff argues that the word requires only that the gate be located somewhere in between the source and the drain.
Plaintiff's construction is the ordinary meaning of the word "between." As plaintiff points out, a chandelier can be "above" a table and "between" the two table ends without extending the table's entire distance. Unless the patent provides a ...