Ex Parte Ungar

Patent Trial and Appeal BoardSep 27, 2012

10264534 (P.T.A.B. Sep. 27, 2012)

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. 10/264,534 10/03/2002 Jeffrey E. Ungar 156900-0016 5352 1622 7590 09/27/2012 IRELL & MANELLA LLP 840 NEWPORT CENTER DRIVE SUITE 400 NEWPORT BEACH, CA 92660 EXAMINER FORDE, DELMA ROSA ART UNIT PAPER NUMBER 2828 MAIL DATE DELIVERY MODE 09/27/2012 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 JEFFREY E. UNGAR ____________ Appeal 2010-002054 Application 10/264,534 Technology Center 2800 ____________ Before HOWARD B. BLAKENSHIP, SALLY C. MEDLEY, and KARL D. EASTHOM, Administrative Patent Judges. PER CURIAM DECISION ON APPEAL STATEMENT OF THE CASE This is an appeal under 35 U.S.C. § 134(a) from the Examiner’s final rejection of claims 1-3, 5, 6, and 13-16, which are all the claims remaining in the application. We have jurisdiction under 35 U.S.C. § 6(b). We reverse. Representative Claim A semiconductor laser, comprising: a semiconductive die that has a top surface and includes a laser strip, said laser strip including: Appeal 2010-002054 Application 10/264,534 2 a gain layer; a diffraction grating feedback layer; and, a reflective surface located along a (111)A crystalline plane of said semiconductive die and located at a 45 degree angle relative to said top surface. Examiner’s Rejections Claims 1-3, 5, 6, and 13-16 stand rejected under 35 U.S.C. § 103(a) as being unpatentable over Blum (US 3,996,528). DISCUSSION Instant claim 1, which we determine to be representative in this appeal, recites that a semiconductive die that has a top surface includes a reflective surface located along a (111)A crystalline plane of the semiconductive die and located at a 45 degree angle relative to the top surface. The Examiner rejects the claim as obvious over Blum. Blum describes an integrated circuit laser having etched grooves 18 (Figs. 2 and 3) between a <111> and a <100> plane, with the groove faces consisting of <111> crystal planes. Blum col. 2, ll. 22-38. However, wall 20 on the <111> plane has an angle greater than 45° such that ray of light 22 is not reflected back to the p-n junction (the amplifying region of the laser). Id. at ll. 52-62. The reference teaches a “chirped” diffraction grating 24 (Figs. 2 and 3) for changing the light path such that the reflected light is substantially perpendicular to current flow in the p-n junction. Id. at col. 2, l. 63 - col. 3, l. 48. The gratings 24 are partially transmissive to lasing light, Appeal 2010-002054 Application 10/264,534 3 so they serve to support lasing oscillations but also to provide outputs for the laser. Id. at col. 3, ll. 24-27. The rejection is unclear in pointing out the structures relied upon in Blum. The rejection refers to a “top surface (see Fig. 3, Character 111).” Ans. 3. Reference numeral 111 in Figure 3 of Blum, however, relates to the <111> plane and the etched <111> surface. It is also unclear what the rejection deems in Blum to correspond to the claimed “reflective surface.” But in the Final Rejection “Response to Arguments” section (at 8), reference is made to Figure 3, which is said to clearly demonstrate “‘a reflective surface (see Fig. 3, Character 18, the reference call[s] ‘groove’) that was etched along (111)A plane and at an angle of 45 degrees’ it is well know[n] in the art.” However, Blum’s disclosure does not teach that groove 18 is etched along a (111) plane at an angle of 45°, but at an angle greater than 45°, which Blum remedies by the addition of “chirped” diffraction grating 24. In any event, the Examiner submits that it would have been obvious to provide a 45° angle relative to the top surface of a semiconductor laser “because it has been shown in the past that 45° is a successful method, see Column 3, Lines 53-55 of Blum.” Ans. 4. Blum provides the following at the relied-upon citation. The use of a chirped grating for an injection laser, such as a solid laser having GaAs as its active element, allows one to use the readily etched <111> surface for the cavity folding mirror to be etched into the GaAs crystal. Such chirped grating will enable one to obtain a folded GaAs laser without restricting one to etch only 45° planes of that GaAs crystal. Blum col. 3, ll. 49-55 (emphasis added). Appeal 2010-002054 Application 10/264,534 4 However, Blum earlier explains the difference between a “readily etched” <111> surface and the etching of 45° planes. It has been discovered that etches along the (001) surface of three-five compounds produce a desirable 45° cut along that surface, so as to allow for laser emission to take place at an angle parallel to the current through the laser, but such (001) surfaces are difficult to etch accurately planar at that angle. It is easier to produce grooves, by chemical etching, with faces along <111> planes, but such <111> planes do not produce 45° cuts or planes, so that the lasing cavity cannot be folded back on itself by the planar mirror scheme described previously. Such etching of the <111> planes produces an angle of about 54.7° between the <111> and <100> planes, rather than a 45° angle, so that light reflected from the 54.7° wall is not reflected back upon itself from the bottom surface of the laser wafer. Blum col. 1, ll. 17-31 (emphasis added). Thus, when read in the context of the patent, the text at column 3, lines 53 through 55 of Blum does not disclose, teach, or suggest that a reflective surface located along a (111)A crystalline plane located at a 45 degree angle relative to the top surface of the semiconductive die has been successfully used in the past. Rather, the reference teaches that the relatively difficult etching along the (001) surface produces a 45° cut along that surface. Blum teaches that the chirped diffraction grating is to be added to allow the relatively simpler etching of <111> planes, because the <111> planes cannot be etched at a 45° angle. Blum col. 1, ll. 17-39. 1 1 Appellant’s solution to the problem of the 54.7° angle between the <111> and <100> planes in conventionally oriented substrates is to provide a vicinally oriented substrate 22 that is inclined by 9.7° degrees from the (100) direction towards the [111] direction, such that the resulting Appeal 2010-002054 Application 10/264,534 5 The Examiner adds what appears to be alternative reasoning in support of the rejection. The selection of the angle relative to the top surface is deemed obvious because “it is a matter of determining optimum process conditions by routine experimentation with a limited number of species of result effective variables.” Ans. 4. However, the allegations are not supported by, and are actually contrary to, the evidence that the Examiner has provided (i.e., Blum). Blum does not suggest that a 45 degree angle consistent with the requirements of instant claim 1 may be attained by “routine experimentation.” Rather, Blum teaches a solution -- a diffraction grating -- to the problem of being unable to attain the 45 degree angle in the arrangement that is claimed. In view of the foregoing, we agree with Appellant that the rejection fails to set forth a prima facie case of obviousness. We cannot sustain the § 103(a) rejection of claims 1-3, 5, 6, and 13-16 over Blum. DECISION The Examiner’s decision to reject claims 1-3, 5, 6, and 13-16 is reversed. REVERSED ak (111)A sidewall 38 is inclined to the surface by 45 degrees. Spec. 8, ll. 14- 20; Fig. 4.