ABLIC Inc.

Patent Trials and Appeals Board

Jan 13, 2022

2021002800 (P.T.A.B. Jan. 13, 2022)

UNITED STATES PATENT AND TRADEMARK OFFICE UNITED STATES DEPARTMENT OF COMMERCE United States Patent and Trademark Office Address: COMMISSIONER FOR PATENTS P.O. Box 1450 Alexandria, Virginia 22313-1450 www.uspto.gov APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO. 16/139,360 09/24/2018 Kazusa OKUDA 11106/1108 1449 757 7590 01/13/2022 Crowell/BGL P.O. BOX 10395 CHICAGO, IL 60610 EXAMINER CHOU, SHIH TSUN A ART UNIT PAPER NUMBER 2811 MAIL DATE DELIVERY MODE 01/13/2022 PAPER Please find below and/or attached an Office communication concerning this application or proceeding. The time period for reply, if any, is set in the attached communication. PTOL-90A (Rev. 04/07) UNITED STATES PATENT AND TRADEMARK OFFICE BEFORE THE PATENT TRIAL AND APPEAL BOARD Ex parte KAZUSA OKUDA and TOSHIRO FUTATSUGI Appeal 2021-002800 Application 16/139,360 Technology Center 2800 Before TERRY J. OWENS, GEORGE C. BEST, AND MERRELL C. CASHION, JR., Administrative Patent Judges. OWENS, Administrative Patent Judge. DECISION ON APPEAL STATEMENT OF THE CASE Pursuant to 35 U.S.C. § 134(a), the Appellant1 appeals from the Examiner’s decision to reject claim 1. We have jurisdiction under 35 U.S.C. § 6(b). We AFFIRM. 1 “Appellant” refers to “applicant” as defined in 37 C.F.R. § 1.42. The Appellant identifies the real party in interest as ABLIC Inc. (Appeal Br. 1). Appeal 2021-002800 Application 16/139,360 2 CLAIMED SUBJECT MATTER Claim 1 is directed to an ultraviolet light receiving element. That claim is: 1. An ultraviolet light receiving element, comprising: a first photodiode sensitive to an ultraviolet light in a first region of a semiconductor substrate, and including a first well implantation layer of a first conductivity type, a first embedded implantation layer of a second conductivity type, and a first surface implantation layer of the first conductivity type, the first embedded implantation layer in the first well implantation layer, the first surface implantation layer in a surface of the semiconductor substrate in the first embedded implantation layer; and a second photodiode insensitive to the ultraviolet light and in a second region of the semiconductor substrate, and including a second well implantation layer of the first conductivity type, a second embedded implantation layer of the second conductivity type, and a second surface implantation layer of the first conductivity type, the second embedded implantation layer in the second well implantation layer, the second surface implantation layer in the surface of the semiconductor substrate in the second embedded implantation layer, the second well implantation layer having a peak concentration position deeper than a peak concentration position of the first well implantation layer by a depth equal to a depth from the surface of the semiconductor substrate to a peak concentration position of the second surface implantation layer. Appeal 2021-002800 Application 16/139,360 3 REFERENCES The prior art relied upon by the Examiner is: Name Reference Date Sugawa (Sugawa-1) US 2017/0176248 A1 June 22, 2017 Sugawa (Sugawa-2) US 2017/0207256 A1 July 20, 2017 REJECTION Claim 1 stands rejected under 35 U.S.C. § 103 over Sugawa-1 in view of Sugawa-2. OPINION Sugawa-1 discloses an ultraviolet light-receiving element (100) comprising: 1) a first photodiode (102b)2 sensitive to an ultraviolet light in a first region (2) of a semiconductor substrate (101), and including a first well implantation layer (103b) of a first conductivity type (1), a first embedded implantation layer (104b) of a second conductivity type (2), and a first surface implantation layer (109b) of the first conductivity type (1), the first embedded implantation layer (109b) being in the first well implantation layer (103b), the first surface implantation layer (109b) being in a surface of the semiconductor substrate (101) in the first embedded implantation layer (104b); and 2) a second photodiode (102a) insensitive to the ultraviolet light and in a second region (1) of the semiconductor substrate (101), and including a second well implantation layer (103a) of the first conductivity type (1), a second embedded implantation layer (104a) of the second conductivity type (2), and a second surface implantation layer (109a) of the first conductivity type (1), the second embedded implantation layer (104a) 2 The terms “first” and “second” are used in the manner that provides consistency with the Appellant’s claim. Appeal 2021-002800 Application 16/139,360 4 being in the second well implantation layer (103a), and the second surface implantation layer (109a) being in the surface of the semiconductor substrate (101) in the second embedded implantation layer (104a) (¶¶ 39, 42, 44, 46, 47, 53, 54; Fig. 1). Sugawa-1 prefers, for design flexibility in measuring harmful UV-rays accurately, that the highest concentration position (106b) of semiconductor impurities in the first well implantation layer (103b) differs from the highest concentration position (106a) of semiconductor impurities in the second well implantation layer (103a) (¶ 51). Sugawa-1 exemplifies a second well implantation layer (103a) having a peak concentration position (565 nm from the semiconductor substrate (100)’s front surface (107)) that is 65 nm deeper than the first well implantation layer (103b)’s peak concentration position (500 nm from the semiconductor substrate (100)’s front surface (107)) (¶¶ 121-123; Fig. 1). Sugawa-1 does not disclose the second surface implantation layer (109a)’s semiconductor impurity peak concentration position (108a) from the semiconductor substrate (101)’s front surface (107) (¶ 57). However, Sugawa-2 discloses a similar light-receiving element (¶¶ 92-101; Fig. 2A) that is substantially free of sensitivity deterioration and increases in dark current due to having a 1x1019 cm-3 or greater maximum concentration of impurity atoms3 at a position (108a) preferably about 50-80 nm from the semiconductor substrate (101)’s surface (107) in the region corresponding to Sugawa-1’s second surface implantation layer (109a) (Sugawa-2, ¶¶ 106, 110, 112, 114). Sugawa-2, therefore, would have suggested, to one of ordinary skill in the art, using a 1x1019 cm-3 or greater peak impurity atom 3 We interpret Sugawa-2’s 1x1,019 cm-3 as 1x1019 cm-3. Appeal 2021-002800 Application 16/139,360 5 concentration (108a) in Sugawa-1’s second surface implantation layer (109a) at a position about 50-80 nm from the semiconductor substrate (101)’s front surface (107) to make the light-receiving element substantially free of sensitivity deterioration and increases in dark current. A 65 nm position within Sugawa-2’s 50-80 nm range would equal the 65 nm peak concentration position difference (565 nm - 500 nm) between the first and second well implantation layers (13a, 13b), thereby meeting the Appellant’s claim requirement of “the second well implantation layer having a peak concentration position deeper than a peak concentration position of the first well implantation layer by a depth equal to a depth from the surface of the semiconductor substrate to a peak concentration position of the second surface implantation layer.” The Appellant argues that “Sugawa-2 explicitly discloses that ‘the maximum concentration position (1-1) 106a and the maximum concentration position (2-1) 106b are preferably the same or substantially the same in depth direction from the position of the surface 107 of the semiconductor substrate 101.’ (Sugawa-2, pg. 7, ¶0147).” (Appeal Br. 7). Sugawa-1 discloses that “to measure the harmful UV-rays more accurately, it is preferred that the highest concentration position (1-1) 106a and the highest concentration position (2-1) 106b be intentionally designed at different positions for design flexibility” (¶ 51). Thus, one of ordinary skill in the art would have positioned the highest concentration positions 106a and 106b at different distances from the substrate (101)’s surface (107) to have design flexibility. Appeal 2021-002800 Application 16/139,360 6 The Appellant argues (Appeal Br. 8): [T]he 50-80 nm range of the junction depth of the surface implantation layer (109a) is not at all related to the maximum concentration position (1-1) (106a) and the maximum concentration position (2-1) (106b). Thus, there is no disclosure that the concentration gradient of a surface layer of an ultraviolet light insensitive photodiode should relate to a difference in the concentration gradient of the well implantation layer with respect to the concentration gradient of the well implantation layer an ultraviolet light sensitive photodiode. Meeting the Appellant’s claim requirements does not require realization of that relation. See In re Beattie, 974 F.2d 1309, 1312 (Fed. Cir. 1992) (“As long as some motivation or suggestion to combine the references is provided by the prior art taken as a whole, the law does not require that the references be combined for the reasons contemplated by the inventor.”). The claim requirements are met when, to substantially avoid sensitivity deterioration and increases in dark current as taught in Sugawa-2 (¶ 110), Sugawa-1’s second surface implantation layer (109a)’s maximum concentration of impurities is 1x1019 cm-3 or greater and the maximum impurity concentration position (108a) is within Sugawa-2’s preferred range of about 50-80 nm from the semiconductor substrate (101)’s surface (107) (¶ 114) at a selected position of 65 nm from that surface (equal to Sugawa-1’s exemplified 65 nm difference between the second well implantation layer (103a)’s highest impurity ion concentration position (106a) (565 nm from the semiconductor substrate (101)’s surface (107)) and the first well implantation layer (103b)’s highest impurity ion concentration position (106b) (500 nm from the semiconductor substrate (101)’s surface (107)) (¶¶ 51, 121-123)). Appeal 2021-002800 Application 16/139,360 7 For the above reasons, we are not persuaded of reversible error in the rejection. CONCLUSION The Examiner’s rejection is affirmed. DECISION SUMMARY In summary: Claim Rejected 35 U.S.C. § Reference(s)/Basis Affirmed Reversed 1 103 Sugawa-1, Sugawa-2 1 TIME PERIOD FOR RESPONSE No time period for taking any subsequent action in connection with this appeal may be extended under 37 C.F.R. § 1.136(a). See 37 C.F.R. § 1.136(a)(1)(iv). AFFIRMED