Document ID: s3://data.kl3m.ai/documents/govinfo/USCOURTS/USCOURTS-ca13-19-01556/USCOURTS-ca13-19-01556-0/pdf.json

Parties Involved:
Andrei Iancu
Intervenor
Lone Star Silicon Innovations LLC
Appellant
Micron Technology, Inc.
Appellee

Document Text:

NOTE: This disposition is nonprecedential.

United States Court of Appeals 

for the Federal Circuit ______________________

LONE STAR SILICON INNOVATIONS LLC,

Appellant

v.

ANDREI IANCU, UNDER SECRETARY OF 

COMMERCE FOR INTELLECTUAL PROPERTY 

AND DIRECTOR OF THE UNITED STATES 

PATENT AND TRADEMARK OFFICE,

Intervenor

______________________

2019-1556

______________________

Appeal from the United States Patent and Trademark 

Office, Patent Trial and Appeal Board in No. IPR2017-

01562.

______________________

Decided: May 14, 2020

______________________

TIMOTHY P. MALONEY, Fitch, Even, Tabin & Flannery, 

Chicago, IL, for appellant. Also represented by NICHOLAS 

T. PETERS, DAVID ALLEN GOSSE. 

 FARHEENA YASMEEN RASHEED, Office of the Solicitor, 

United States Patent and Trademark Office, Alexandria, 

VA, for intervenor. Also represented by THOMAS W.

Case: 19-1556 Document: 52 Page: 1 Filed: 05/14/2020
2 LONE STAR SILICON INNOVATIONS v. IANCU

KRAUSE, AMY J. NELSON, MOLLY R. SILFEN, MEREDITH 

HOPE SCHOENFELD. 

 ______________________

Before CHEN, HUGHES, and STOLL, Circuit Judges.

CHEN, Circuit Judge.

Lone Star Silicon Innovations LLC (Lone Star) appeals

from the Final Written Decision by the Patent Trial and 

Appeal Board (Board) in inter partes review (IPR) No. 

IPR2017-01562. The Board held that all challenged claims 

of U.S. Patent No. 6,097,061 (the ’061 patent), claims 1, 3–

6, 11, and 13–16, are unpatentable. Lone Star’s appeal centers on the Board’s claim construction of the phrase “a 

channel region formed in the semiconductor substrate” in 

independent claims 1 and 11 and obviousness conclusion 

for dependent claims 6 and 16. 

Because the Board correctly applied the established ordinary meaning in the art for the “channel region” limitation and we see no error in the Board’s conclusion of 

obviousness for dependent claims 6 and 16, we affirm.

BACKGROUND

The ’061 patent, entitled “Trenched Gate Metal Oxide 

Semiconductor Device and Method,” is directed to a Metal 

Oxide Semiconductor (MOS) transistor having a trenched 

gate.1 ’061 patent col. 1 ll. 46–57. Conventional MOS transistors include a semiconductor substrate having a source 

region, drain region, and a channel region between the 

source and drain regions, with a gate dielectric layer and a 

1 Lone Star argues that the ’061 patent is also directed to methods of manufacture, but all the claims are for 

a semiconductor device. A subsequent divisional patent 

sets forth manufacturing method claims. See U.S. Patent 

No. 6,667,227. 

Case: 19-1556 Document: 52 Page: 2 Filed: 05/14/2020
LONE STAR SILICON INNOVATIONS v. IANCU 3

gate electrode layer disposed on the top surface of the semiconductor substrate directly above the channel region. Id.

at col. 1 ll. 28–34. According to the patent, having the gate 

formed on top of the substrate limits “the degree to which 

active devices can be made smaller in order to improve 

packing density and performance.” Id. at col. 1 ll. 41–43. 

The specification describes its solution to this problem 

in the “Summary of the Invention” section: “In accordance 

with the present invention, a semiconductor device is fabricated to include a trenched polysilicon gate which is 

formed in a trench of a semiconductor substrate.” Id. at

col. 1 ll. 46–48. The patent goes on to say that positioning 

the gate within a trench in the substrate provides benefits 

over conventional gate structures, including “better process control and improved manufacturability.” Id. at col. 1

ll. 49–51. In addition, “[t]he trenched polysilicon gate 

structure of the present invention” improves the device 

packing density and scalability. Id. at col. 1 ll. 51–55. The 

patent then describes a number of different embodiments 

showing how the trenched gate is incorporated into an otherwise standard MOS transistor, each embodiment disclosing a source region, drain region, and channel region in 

combination with a trenched gate. 

Claim 1 is representative and recites: 

1. A semiconductor transistor comprising:

a semiconductor substrate of a first conductivity 

type;

a source region of a second conductivity type in the 

semiconductor substrate;

a drain region of the second conductivity type spaced 

from the source region in the semiconductor substrate;

a trench having substantially upright vertical surfaces and a bottom surface formed in the 

Case: 19-1556 Document: 52 Page: 3 Filed: 05/14/2020
4 LONE STAR SILICON INNOVATIONS v. IANCU

semiconductor substrate intermediate the source 

and drain regions;

a channel region formed in the semiconductor substrate, the channel region forming a contiguous region beneath the bottom surface of the trench and 

immediately contiguous to the source and drain regions;

a trench-to-gate insulating layer formed on the substantially upright vertical surfaces and the bottom 

surface inside the trench, the trench-to-gate insulating layer forming a contiguous layer inside the 

trench; and

a trenched gate electrode having a top surface and 

formed on the trench-to-gate insulating layer inside 

the trench. 

’061 patent claim 1 (emphasis added). 

On June 9, 2017, Micron Technology, Inc. (Micron) filed 

an IPR petition against the ’061 patent challenging claims 

1, 3–6, 11, and 13–16. The Board instituted the IPR, and 

issued its Final Written Decision, finding all challenged 

claims unpatentable. Micron Tech. Inc. v. Lone Star Silicon Innovations LLC, IPR2017-01562, at 40 (P.T.A.B. Dec. 

13, 2018). Specifically, the Board found that claims 1, 3–5, 

11, and 13–15 would have been obvious over U.S. Patent 

No. 5,408,116 (Tanaka), claims 6 and 16 would have been 

obvious over Tanaka and U.S. Patent No. 5,283,449 (Ooka), 

and claims 1, 3, 4, 11, 13, and 14 would have been obvious 

over U.S. Patent No. 5,300,447 (Anderson). It is undisputed that both Tanaka and Anderson are directed to MOS 

transistors having a gate formed in a trench within the 

semiconductor substrate. Appellant’s Br. at 13, 20.

In a thorough, extensive analysis, the Board construed 

the phrase “a channel region formed in the semiconductor 

substrate” recited in independent claims 1 and 11. 

Case: 19-1556 Document: 52 Page: 4 Filed: 05/14/2020
LONE STAR SILICON INNOVATIONS v. IANCU 5

Applying the Phillips v. AWH Corp. standard,2 the Board 

rejected Lone Star’s proposed claim construction of “a channel region defined by the presence of dopants that are separate or additional relative to the semiconductor substrate 

of a first conductivity type.” Micron, IPR2017-01562, at 8

(citing 415 F.3d 1303, 1312–19 (Fed. Cir. 2005) (en banc)). 

The Board found that, while the claim term encompassed 

a channel region implanted with an additional or separate 

dopant, neither the claim language itself nor the specification limited the claimed “channel region” to require that 

attribute. Rather, the Board concluded that it should apply 

the well-established ordinary meaning of this claimed 

phrase in the MOS transistor art: “the region circumscribed by the gate, gate oxide, source, and drain in a transistor; that is, the place in the transistor where a channel 

forms during normal operation or use, regardless of 

whether the channel is doped differently than the substrate.” Id. at 9, 23–24. In other words, the “textbook way” 

of forming a channel region in the substrate for a MOS 

transistor was through the formation of the surrounding 

source, drain, and gate structures. Id. at 9.

As to the specification, the Board recognized that it described a number of illustrative examples in which the

channel region is implanted with a dopant. But because 

those references to an implanted channel region consistently were in the context of describing “one embodiment” 

or a “preferred embodiment” of the invention, the Board 

found these references to be only “exemplary in nature” 

and declined to read the limitation of implanting a dopant 

into the claimed “channel region.” Id. at 21–22. 

Instead, the Board agreed with Micron that a skilled 

artisan in the relevant art would understand that “a 

2 The Board applied the Phillips standard because 

the patent had expired. Micron, IPR2017-01562, at 8 (citing In re Rambus Inc., 694 F.3d 42, 46 (Fed. Cir. 2012)).

Case: 19-1556 Document: 52 Page: 5 Filed: 05/14/2020
6 LONE STAR SILICON INNOVATIONS v. IANCU

channel region” can be formed in relation to the source, 

drain, and gate structures. The Board relied heavily on a 

college textbook discussing the typical structure of MOS 

transistors. ADEL S. SEDRA & KENNETH C. SMITH,

MICROELECTRONIC CIRCUITS (3d ed. 1991) (Sedra). More 

particularly, the Board relied on Sedra’s Figure 5.1 below 

showing a standard MOS transistor. 

Id. at 300. 

Case: 19-1556 Document: 52 Page: 6 Filed: 05/14/2020
LONE STAR SILICON INNOVATIONS v. IANCU 7

The Board stated, “Figure 5.1 includes perspective and 

cross sectional views of the physical structure of an n-type 

metal oxide semiconductor (‘NMOS’) transistor, and depicts a channel region in relation to the other transistor 

structures, including the gate, gate oxide, source, drain, 

and substrate body of the semiconductor device.” Micron, 

IPR2017-01562, at 13; see also id. at 14 (discussing Sedra’s

equivalent disclosure for a p-type transistor). Sedra explains and illustrates that the “channel region” refers to 

the region of the substrate underneath the gate and 

bounded by the “source region” and “drain region,” where 

“current will flow” once a voltage is applied to the gate. 

SEDRA, supra at 301. The Board also pointed to Anderson

and Principles of CMOS VLSI Design: A Systems Perspective, by Neil H.E. Weste & Kamran Eshraghian (the Weste 

treatise), as further evidence showing that skilled artisans 

at the time of the invention understood that a MOS transistor channel does not require any separate doping, but 

instead can be defined by the formation of the surrounding 

source, drain, and gate. Micron, IPR2017-01562, at 15. 

Additionally, the Board noted that Lone Star’s expert, Dr. 

Bottoms, conceded that textbooks provided the standard 

use of the term “channel region” as referring to the region 

between the source and drain where an induced current 

will be formed when a voltage is applied to the gate. Id. at 

14 (citing J.A. 1713–14). Because the Board concluded that 

nothing in the claims or specification conveyed with sufficient clarity an intent to alter the established meaning in 

the art for “channel region formed in a semiconductor substrate,” it construed the claimed phrase in keeping with its 

established meaning. Given that claim construction, the 

Board found all of the challenged claims unpatentable for 

the reasons raised by the petitioner. 

Lone Star appealed. We have jurisdiction pursuant to 

28 U.S.C. § 1295(a)(4)(A).

Case: 19-1556 Document: 52 Page: 7 Filed: 05/14/2020
8 LONE STAR SILICON INNOVATIONS v. IANCU

DISCUSSION

I. Claim Construction

Claim construction is as a question of law that may involve underlying fact inquiries. Teva Pharm. USA, Inc. v. 

Sandoz, Inc., 574 U.S. 318, 326 (2015); Wi-LAN USA, Inc. 

v. Apple Inc., 830 F.3d 1374, 1381 (Fed. Cir. 2016). This 

court reviews the Board’s claim construction based solely 

on intrinsic evidence de novo, and reviews subsidiary fact 

findings as to extrinsic evidence for substantial evidence. 

HTC Corp. v. Cellular Commc’ns Equip., LLC, 877 F.3d 

1361, 1367 (Fed. Cir. 2017). 

When construing the claims of an expired patent, the 

Board applies a district court-type claim construction 

standard. See In re Rambus, 694 F.3d 42, 46 (Fed. Cir. 

2012). Under that standard, claim terms are given their 

ordinary and customary meaning, as would be understood 

by a person of ordinary skill in the art at the time of invention in light of the claim language, the specification, and 

prosecution history. Phillips, 415 F.3d at 1312–17. We 

have explained that “there is no magic formula” for conducting claim construction, and what matters is not necessarily the sequence of steps in consulting various sources; 

“what matters is for the court to attach the appropriate 

weight to be assigned to those sources in light of the statutes and policies that inform patent law.” Id. at 1324 (citing Vitronics Corp. v. Conceptronic, Inc., 90 F.3d 1576, 

1582 (Fed. Cir. 1996)). While “in general, certain types of 

evidence are more valuable than others,” a judge who encounters a disputed claim term has the discretion to consider, as a starting point, dictionaries, treatises and 

textbooks to understand how one of skill might use that 

claim term, “as long as those sources are not used to contradict claim meaning that is unambiguous in light of the 

intrinsic evidence.” Id. at 1324. For example, our court 

has on occasion first ascertained the meaning in the relevant technical field of a term recited in a claim before 

Case: 19-1556 Document: 52 Page: 8 Filed: 05/14/2020
LONE STAR SILICON INNOVATIONS v. IANCU 9

considering how the patentee used that term in the context 

of the patent. See, e.g., Ancora Techs., Inc. v. Apple, Inc., 

744 F.3d 732 (Fed. Cir. 2014); Starhome GmbH v. AT&T 

Mobility LLC, 743 F.3d 849 (Fed. Cir. 2014). “A claim term 

should be given its ordinary meaning in the pertinent context, unless the patentee has made clear its adoption of a 

different definition or otherwise disclaimed that meaning.” 

Ancora, 744 F.3d at 734. The patent may provide such a 

clear intent either expressly or by implication. Luminara 

Worldwide, LLC v. Liown Elecs. Co., 814 F.3d 1343, 1353 

(Fed. Cir. 2016).

Lone Star contends that the Board incorrectly construed “channel region formed in the semiconductor substrate” in accordance with the well-established ordinary 

meaning in the MOS transistor art, because, in Lone Star’s

view, the patent claims and specification clearly require

the channel region to be implanted with its own dopant. 

While the claim language and specification are always the 

most important sources of evidence to any claim construction inquiry, we agree with the Board in this case that the 

intrinsic evidence lacks the needed clarity to import a dopant implantation requirement into the claimed channel 

region.

The Board correctly found that the record shows that a 

“channel region formed in the semiconductor substrate”

had a well-understood meaning in the MOS transistor art 

at the time of the invention. The term generally refers to 

the region of the substrate located under the gate and 

bounded by the source and drain regions in a MOS transistor. As Sedra, a standard college textbook in the field, illustrates in Figure 5.1, a “channel region” is defined by the 

formation of the surrounding source region, drain region, 

and gate, without this area requiring any separate processing or alteration with any additional dopants, for example. SEDRA, supra at 299–301. Sedra describes that 

what its figure labels as the “channel region” in the substrate is where current will flow between the drain and 

Case: 19-1556 Document: 52 Page: 9 Filed: 05/14/2020
10 LONE STAR SILICON INNOVATIONS v. IANCU

source when a voltage is applied to the gate during use. Id. 

at 301. 

Moreover, the testimony of Dr. Bottoms, Lone Star’s 

own expert, was consistent with the view of Dr. Fair, Micron’s expert, when Dr. Bottoms explained that the industry understanding of “channel region” was the region in the 

substrate “that’s bounded by the gate and the source and 

the drain . . . . so that space in the substrate but under the 

gate and between the source and the drain is often referred 

to as a channel region.” J.A. 1713–14; see also J.A. 1226, 

1228 (“The formation of [the drain and source regions and 

gate structures] in turn forms the ‘channel region’ because 

it is these structures that delineate where the induced 

channel will form.”), 1230 (“It is this delineation [of the 

channel region with the source/drain, gate oxide, and gate], 

that gives meaning to the word ‘formed’ because it forms or 

shapes the channel region.”). In addition, the Weste treatise and Anderson further reinforce the Board’s finding 

that skilled artisans understood that a channel is formed 

in the substrate through the formation of the source, drain, 

and gate, without any requirement for separate doping. 

NEIL H.E. WESTE & KAMRAN ESHRAGHIAN, PRINCIPLES OF 

CMOS VLSI DESIGN: A SYSTEMS PERSPECTIVE 41–42 (2d ed. 

1993) (describing the channel as the “region immediately 

under the gate” and “between the source and the drain”); 

Anderson, at Abstract (describing first “forming a gate,” 

“and then forming source and drain regions,” “thus forming 

the transistor channel.”). Despite Lone Star’s arguments 

to the contrary, substantial evidence supports the Board’s 

finding that the disputed phrase had a well-established, ordinary meaning in the relevant art, a meaning that did not 

require separate doping.

Considering “channel region formed in the semiconductor substrate” in the context of the claims and specification,

one of ordinary skill would have understood that the inventors did not depart from the established, ordinary meaning 

of the phrase. As the Board correctly observed, the 

Case: 19-1556 Document: 52 Page: 10 Filed: 05/14/2020
LONE STAR SILICON INNOVATIONS v. IANCU 11

language of the claims “nowhere mentions a channel region 

defined by the presence of dopants.” Micron, IPR2017-

01562, at 9. The claim language of “formed in a semiconductor substrate” does not itself alter the meaning of “channel region” from the ordinary understanding of this phrase. 

As explained above, skilled artisans understood that a 

channel region can be “formed in the substrate” simply 

through the formation of the surrounding structures that 

define the contours of the channel region. This phrase thus 

does not, by itself, require an interpretation different from 

the ordinary meaning. Lone Star’s reliance on other usages 

of “formed” in the claims, such as “a trenched gate electrode . . . formed on the trench-to-gate insulating layer,” is 

unpersuasive for the same reason: it fails to account for 

the established industry understanding of how a channel 

region is “formed” through the creation of its surrounding 

transistor structures. The claim does not indicate that it is 

using the phrase “channel region formed in the semiconductor substrate” any differently from the established ordinary meaning. 

We also disagree with Lone Star that the Board’s construction renders superfluous the claim phrase reciting

“the channel region forming a contiguous region beneath 

the bottom surface of the trench and immediately contiguous to the source and drain regions.” As an initial matter, 

it is not clear why this additional phrase would be considered superfluous under the Board’s construction but not 

Lone Star’s: its preferred construction of “channel region 

formed in the semiconductor substrate” already requires a 

dopant to be implanted in the channel region. If that is 

correct, then, based on Lone Star’s “superfluous” argument, there would be no work to do for the follow-on “forming” phrase. Moreover, Lone Star’s argument as to the 

meaning of the follow-on “forming” phrase fails for the 

same reason as the “formed” phrase, explained above. In 

any event, we do not see the Board’s construction as necessarily rendering the “forming” phrase superfluous, given 

Case: 19-1556 Document: 52 Page: 11 Filed: 05/14/2020
12 LONE STAR SILICON INNOVATIONS v. IANCU

that it clarifies, in the context of the assertedly novel 

trenched gate, that the inventors have defined the “channel 

region” to have the customary attribute of being contiguous 

with the source and drain regions, despite the existence of 

a trench. At bottom, Lone Star’s arguments are premised 

on the view that the specification altered the meaning of 

“channel region formed in the semiconductor substrate,” 

but, as explained below, we do not believe that to be the 

case.

After a careful review, we agree with the Board that

the specification does not show a clear intent, either expressly or implicitly, to redefine the “channel region” limitation to require an additional dopant. To be sure, the

specification discloses examples of a trenched gate MOS 

transistor in which the substrate is implanted with a dopant to form a channel region. See, e.g., ’061 patent col. 5

ll. 36–38. But each of the instances in which the specification discusses an implanted channel region is in the context of describing “one embodiment” or a “preferred 

embodiment” of the invention. Id. at col. 1 ll. 58, 62–64,

col. 2 ll. 7–11, col. 3 ll. 20–23, col. 4 ll. 54–55, col. 5 ll. 36–

45. These examples are “not sufficient to redefine” the 

meaning of “channel region.” See Ancora, 744 F.3d at 735

(quoting IGT v. Bally Gaming Int’l, Inc., 659 F.3d 1109, 

1118 (Fed. Cir. 2011)) (ruling that the specification’s description for a “preferred embodiment,” which was consistent with descriptions of other disclosed embodiments, 

was not limiting). 

Using a term the same way in all disclosed embodiments is not by itself sufficient to redefine a term with an 

established ordinary meaning in the art. See Aventis 

Pharma S.A. v. Hospira, Inc., 675 F.3d 1324, 1330 (Fed.

Cir. 2012) (“[I]t is . . . not enough that the only embodiments, or all of the embodiments, contain a particular limitation to limit a claim term beyond its ordinary meaning.” 

(internal quotations omitted)); CCS Fitness, Inc. v. Brunswick Corp., 288 F.3d 1359, 1366 (Fed. Cir. 2002) (stating 

Case: 19-1556 Document: 52 Page: 12 Filed: 05/14/2020
LONE STAR SILICON INNOVATIONS v. IANCU 13

that a party may “narrow a claim term’s ordinary meaning, 

but he cannot do so simply by pointing to the preferred embodiment or other structures or steps disclosed in the specification or prosecution history”). The specification “must 

have sufficient clarity to put one reasonably skilled in the 

art on notice that the inventor intended to redefine the 

claim term.” Merck & Co. v. Teva Pharms. USA, Inc., 395 

F.3d 1364, 1370 (Fed. Cir. 2005); see also Innova/Pure Water, Inc. v. Safari Water Filtration Sys., 381 F.3d 1111, 1117 

(Fed. Cir. 2004) (“[E]ven where a patent describes only a 

single embodiment, claims will not be read restrictively unless the patentee has demonstrated a clear intention to 

limit the claim scope.” (internal quotation omitted)). Lone 

Star’s citations to the contrary do not teach otherwise and 

are not persuasive. See Enzo Biochem Inc. v. Applera 

Corp., 780 F.3d 1149, 1156 (Fed. Cir. 2015) (finding that 

“direct detection” was not in the scope of the claim because 

the court's “analysis of the totality of the specification[] 

clearly indicates that the purpose of this invention was directed towards indirect detection, not direct detection”); 

Regents of Univ. of Minn. v. AGA Med. Corp., 717 F.3d 929,

935–36 (Fed. Cir. 2013) (holding that “the claim language 

fully supports” the court’s claim construction and that the 

construction was further supported by the specification describing the term as part of the “present invention” that 

was disclosed in every embodiment); PODS, Inc. v. Porta 

Stor, Inc., 484 F.3d 1359, 1366–67 (Fed. Cir. 2007) (construing “carrier frame” based on claim differentiation and 

finding that consistent usage and statements distinguishing the prior art in the prosecution history supported that 

definition).

Lone Star’s noted specification statements neither define “channel region” nor exclude any portion of the established ordinary meaning. More specifically, the 

specification at no time excludes the textbook understanding of a channel region from falling within “channel region.” Moreover, the specification never characterizes its 

Case: 19-1556 Document: 52 Page: 13 Filed: 05/14/2020
14 LONE STAR SILICON INNOVATIONS v. IANCU

references to the “channel region” as part of the patent’s 

inventive contribution, or providing particular advantages 

or a novel distinction over prior art MOS transistors. See 

SunRace Roots Enter. Co. v. SRAM Corp., 336 F.3d 1298, 

1305 (Fed. Cir. 2003) (“[T]his is not a case in which a feature was described in the written description as critical but 

was never explicitly listed in the claim language, suggesting that the relevant structure in the claims should be narrowly construed as having that feature. Rather, in this 

case, the cam feature was explicitly included as an element 

in numerous claims, but not in the claim in suit.”); see also

SciMed Life Sys., Inc. v. Advanced Cardiovascular Sys., 

Inc., 242 F.3d 1337, 1343–44 (Fed. Cir. 2001) (finding that 

“the SciMed patents distinguish the prior art on the basis 

of the use of dual lumens and point out the advantages of 

the coaxial lumens used in the catheters that are the subjects of the SciMed patents” and that the specification included these dual lumens as part of “the present 

invention”); Alloc, Inc. v. Int’l Trade Comm’n, 342 F.3d 

1361, 1371 (Fed. Cir. 2003) (“[T]he ’907 specification indicates that the invention is indeed exclusively directed toward flooring products including play. Moreover, unlike 

the patent-at-issue in Sunrace, the ’907 specification also 

distinguished the prior art on the basis of play.”). In this 

case, the specification characterizes just one particular feature that “advantageously improves” “the present invention” over “conventional MOS circuits”—the trenched gate. 

Accordingly, we conclude that the Board properly weighed 

the various sources of evidence and correctly rejected Lone 

Star’s proposed claim construction. 

II. Dependent Claims 6 and 16

For claims 6 and 16, Lone Star also challenges the 

Board’s finding that these dependent claims would have 

been obvious in view of Tanaka and Ooka. Lone Star contends that the Board did not give appropriate consideration 

to its arguments that the two references are incompatible.

We find that the Board reasonably considered and weighed 

Case: 19-1556 Document: 52 Page: 14 Filed: 05/14/2020
LONE STAR SILICON INNOVATIONS v. IANCU 15

Lone Star’s arguments, and we agree with the Board’s ultimate conclusion of obviousness. 

The references themselves provide evidence supporting 

a finding that a skilled artisan would have been motivated 

to combine the tungsten silicide layer onto the Tanaka gate 

structure. As the Board found, Tanaka discusses that resistance increases in semiconductors can result in slower

operating speed. Tanaka col. 1 ll. 10–20, col. 3 l. 68–col. 4

l. 2; Ooka col. 1 ll. 18–33; see also Micron, IPR2017-01562, 

at 34–35. Ooka specifically addressed this challenge by 

providing a tungsten silicide layer onto the gate to lower 

resistance. Ooka col. 1 ll. 34–44. Further, Ooka states that 

its teachings are for “semiconductor integrated circuit devices including MOSFETs.” Id. at col. 1 ll. 18–25. Ooka 

also specifically stated that adding such a silicide layer was 

a recent trend in the art (i.e., was known at the time), and 

contemplated ways to fix certain complications created by 

these layers. Id. at col. 1 ll. 34–44, col. 1 l. 62–col. 2 l. 25. 

We agree with the Board that nothing in these teachings

suggests that the two references would not be combined. 

Moreover, the Board relied on Micron’s expert, Dr. Fair, 

who explained that conventional methods could have been 

used to properly include a layer of tungsten silicide on the 

top of Tanaka’s gate electrode. Micron, IPR2017-01562, at 

35 (citing J.A. 960). 

The Board found Lone Star’s incompatibility argument 

to be unpersuasive, amounting to “bare attorney argument.” Micron, IPR2017-01562, at 36. In its Patent Owner 

Response, which was lengthy and made several different 

arguments, Lone Star briefly asserted that placing a silicide on top of Tanaka’s gate electrode would introduce unwanted capacitance. J.A. 345. It also asserted that the 

silicide on the gate electrode “would likely short between 

the source and the drain.” J.A. 346. While the Board did 

not expressly address these specific bases for incompatibility in its Final Written Decision, “the Board is ‘not require[d] . . . to address every argument raised by a party or 

Case: 19-1556 Document: 52 Page: 15 Filed: 05/14/2020
16 LONE STAR SILICON INNOVATIONS v. IANCU

explain every possible reason supporting its conclusion.’” 

Yeda Research v. Mylan Pharm. Inc., 906 F.3d 1031, 1046 

(Fed. Cir. 2018) (quoting Synopsys, Inc. v. Mentor Graphics 

Corp., 814 F.3d 1309, 1322 (Fed. Cir. 2016), overruled on 

other grounds by Aqua Prods., Inc. v. Matal, 872 F.3d 1290, 

1296 n.1 (Fed. Cir. 2017) (en banc)). Indeed, “[a]s we have 

said numerous times, failure to explicitly discuss every 

fleeting reference or minor argument does not alone establish that the Board did not consider it.” Id. (citing Novartis 

AG v. Torrent Pharm. Ltd., 853 F.3d 1316, 1328 (Fed. Cir. 

2017)). Even assuming that the Board had failed to consider these arguments, they would not change the result 

here. Each of Lone Star’s assertions included a pinpoint 

citation to the declaration of its expert, Dr. Bottoms. That 

declaration, however, fares no better than Lone Star’s brief 

argument, because it provides little more than the same 

assertion without any meaningful additional support. Under these circumstances, we see no error in the Board rejecting Lone Star’s skeletal arguments. See TQ Delta, LLC 

v. Cisco Sys., Inc., 942 F.3d 1352, 1358 (Fed. Cir. 2019) 

(“Conclusory expert testimony does not qualify as substantial evidence.”). Substantial evidence supports the Board’s 

conclusion of obviousness for claims 6 and 16.

CONCLUSION

We have considered Lone Star’s remaining arguments 

but find them unpersuasive. Consistent with the above, we 

affirm the Board’s decision. We agree that the claim term 

“channel region formed in the semiconductor substrate” 

should be interpreted in accordance with its established ordinary meaning in the art at the time of the invention. We 

further find that there was substantial evidence supporting the Board’s finding of obviousness for claims 6 and 16. 

AFFIRMED

COSTS

No costs.

Case: 19-1556 Document: 52 Page: 16 Filed: 05/14/2020