Ex Parte Jain

Patent Trial and Appeal Board

Aug 29, 2016

11379426 (P.T.A.B. Aug. 29, 2016)

UNITED STA TES p A TENT AND TRADEMARK OFFICE APPLICATION NO. FILING DATE 111379,426 0412012006 23494 7590 08/31/2016 TEXAS INSTRUMENTS IN CORPORA TED P 0 BOX 655474, MIS 3999 DALLAS, TX 75265 FIRST NAMED INVENTOR Amitabh Jain 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 ATTORNEY DOCKET NO. CONFIRMATION NO. TI-38399.1 9829 EXAMINER LI,MEIYA ART UNIT PAPER NUMBER 2811 NOTIFICATION DATE DELIVERY MODE 08/31/2016 ELECTRONIC 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. Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the following e-mail address( es): uspto@ti.com PTOL-90A (Rev. 04/07) UNITED STATES PATENT AND TRADEMARK OFFICE BEFORE THE PATENT TRIAL AND APPEAL BOARD Ex parte AMIT ABH JAIN Appeal2015-000117 Application 11/379,426 Technology Center 2800 Before ROMULO H. DELMENDO, MARK NAGUMO, and JULIA HEANEY, Administrative Patent Judges. DELMENDO, Administrative Patent Judge. DECISION ON APPEAL The Applicant (hereinafter the "Appellant") 1 appeals under 35 U.S.C. § 134(a) from a final decision of the Primary Examiner to reject claims 22- 26 and 29-32.2 We have jurisdiction under 35 U.S.C. § 6(b). We affirm. 1 The Appellant states that the Real Party in Interest is "Texas Instruments Incorporated" (Appeal Brief filed February 21, 2014, hereinafter "Br.," 3). 2 See Br. 1, 10-24; Final Office Action delivered electronically on September 9, 2013, hereinafter "Final Act.," 1. Appeal2015-000117 Application 11/379,426 BACKGROl.J1'-JD The subject matter on appeal relates to a semiconductor wafer provided with SiGe source/drain extensions having a high level of evenly- distributed dopants and highly abrupt junctions (Specification filed April 20, 2006, hereinafter "Spec.," i-fi-f l; 14--16). Figure 1, which depicts an embodiment of the claimed wafer, is reproduced below. 130 170 180 190 160 170 180 \ ) I / \ ----i I >------------------~---< ·40 i w I ,-------------------------------------~ I 120 ! ~-----1-10---1-aii---------~;-90 _____ ,. ______ 1-60------------1-10---1-aii-- 1 ' / ) I I I I I L 40 20/ PMOS ------------------ 2 FlG.1 Appeal2015-000117 Application 11/379,426 Figure 1 above is described as a cross-sectional view of a partially fabricated semiconductor wafer in accordance with the Appellant's invention (Spec. i-f 2). Specifically, Figure 1 shows a wafer 10 including, inter alia, a PMOS (i.e., a p-channel metal oxide semiconductor) transistor 120 and an NMOS (i.e., an n-channel metal oxide semiconductor) transistor 130, wherein each of the transistors 120, 130 contains a deep source/drain 80, a Si Ge source/drain extension 90, and a gate comprised of a gate oxide dielectric 100 and a gate polysilicon electrode 110 (Spec. i-fi-1 7-9). The PMOS source/drain extension 90 is said to be doped with p-type dopants (e.g., B or BF2), while the NMOS source/drain extension is said to be doped with n- type dopants (e.g., P or P and As) (id. i-fi-18-9, 14). According to the Appellant, "[t]hese heavily doped (i.e., highly activated) SiGe source/drain extensions 90 having evenly distributed dopants and highly abrupt edges have a lowered sheet resistance and thereby improved scalability" (id. i-f 16). Representative claim 22 is reproduced from page 26 of the Appeal Brief (Claims Appendix) as follows (bracketed reference numerals and emphases added): 22. A semiconductor wafer [10] having a PMOS transistor [120] and an NMOS transistor [130], each containing a source [80], a drain [80], and a gate silicon oxide layer [100], compnsmg: an NMOS source/drain extension [90] of said NMOS transistor [130] within said semiconductor wafer [10] and contacting said source [80] and said drain [80], said NMOS source/drain extension composed of SiGe, said NMOS source/drain extension [90] contains evenly distributed dopants, said NMOS source/drain extension [90] is highly doped, and said NMOS source/drain extension [90] has highly abrupt junctions; and a PMOS source/drain extension [90] of said PMOS transistor [130] within said semiconductor wafer [10] and 3 Appeal2015-000117 Application 11/379,426 contacting said source [80] and said drain [80], said PivIOS source/drain extension [90] composed of SiGe, said PMOS source/drain extension [90] contains evenly distributed dopants, said PMOS source/drain extension [90] is highly doped, and said PMOS source/drain extension [90] has highly abrupt junctions. THE REJECTION Claims 22-26 and 29-32 stand rejected under 35 U.S.C. § 103(a) as unpatentable over Samoilov et al. (hereinafter "Samoilov"), 3 Essaian et al. (hereinafter "Essaian"),4 and Yu et al. (hereinafter "Yu")5 (Examiner's Answer delivered electronically on July 21, 2014, hereinafter "Ans.," 2-12; Final Act. 2-6). DISCUSSION Unless argued separately pursuant to 37 C.F.R. § 41.37(c)(l)(iv), the rejected claims stand or fall together with claim 22, which we select as representative. Merely asserting that the prior art references do not disclose or suggest a claim limitation is not an argument for separate patentability in accordance with the rule. In re Lovin, 652 F.3d 1349, 1356-57 (Fed. Cir. 2011). I. Claim 22 The Examiner found that Samoilov describes every limitation recited in claim 22 except it does not state that the PMOS and NMOS source/drain 3 US 2005/0079692 Al published April 14, 2005. 4 US 6,589,364 Bl issued July 8, 2003. 5 Bin Yu et al., 70nm MOSFET with Ultra-Shallow, Abrupt, and Super- Doped SID Extension Implemented by Laser Thermal Process (LTP), Electron Devices Meeting, '99 IEDM 509-512 (1999). 4 Appeal2015-000117 Application 11/379,426 extensions disclosed therein contain "evenly distributed dopants," are "highly doped," and have "highly abrupt junctions," as required by the claim (Final Act. 2-3). The Examiner found further, however, that Essaian and Yu provide teachings that account for the limitations missing in Samoilov (id. at 3). Specifically, the Examiner found that Essaian teaches producing, by laser annealing, a highly-doped SiGe material in which the dopants are evenly distributed and further that Yu teaches a highly-doped source/drain extension material including evenly distributed dopants and highly abrupt junctions (id.). Based on these findings, the Examiner concluded that a person having ordinary skill in the art would have combined the references in the manner claimed by the Appellant "in order to improve the performance of the device, minimize the system operational speed restrictions, [and to] reduce the cost and the size of the device" (id.). The Appellant does not dispute the Examiner's finding (Final Act. 2) that Samoilov discloses, or would have suggested, a semiconductor wafer having both a PMOS transistor and an NMOS transistor, each transistor including a source, a drain, and a gate silicon oxide layer (Br. 10-13). Rather, the Appellant contends that Samoilov "does not teach the advantageously claimed invention because [it] does not teach an NMOS source/drain extension composed of SiGe that contacts the source/drain and also contains evenly distributed dopants, is highly doped, and has highly abrupt edges" (Br. 10) (internal citations omitted). That is, although the Appellant concedes that "Samoilov ... teaches the use of Si Ge for PMOS transistors[,]" the Appellant argues that the reference "teaches away from the claimed invention by teaching an NMOS source/drain extension that is not composed of SiGe"-i.e., Samoilov does not disclose "the sole use of doped 5 Appeal2015-000117 Application 11/379,426 SiGe for NivIOS transistors ... as advantageously claimed" (id. at 10-11) (emphases added). The Appellant urges that Samoilov "teaches away from using SiGe as the source/drain extension ofNMOS transistors due to its problematic compressive stress" (id. at 11 ). The Appellant argues further that Essaian and Yu also teach away because: (i) Essaian teaches a heterojunction bipolar transistor (HBT) having a silicon-germanium base instead of an NMOS transistor; and (ii) Yu does not teach a source/drain extension composed of SiGe (id. at 11-12). Thus, according to the Appellant, "the combination of [the three references] also does not teach an NMOS source/drain extension composed of SiGe that contacts the source/ drain and also contains evenly distributed dopants, is highly doped, and has highly abrupt junctions" (id. at 12) and, in view of certain differences in the prior art teachings relative to each other, a person having ordinary skill in the art would not have combined the references in the manner claimed by the Appellant (id. at 13). The Appellant's arguments fail to identify or reveal a reversible error in the Examiner's rejection of claim 22. In re Jung, 637 F.3d 1356, 1365 (Fed. Cir. 2011). As an initial matter, the Appellant fails to provide any meaningful discussion in the arguments on why it is believed that claim 22 is limited to "the sole use of doped Si Ge for NMOS transistors" (Br. 11) (emphasis added). Nothing in claim 22, by virtue of the open language "comprising" appears to exclude other elements or layers as part of the claimed semiconductor wafer. Although claim 22 recites "said NMOS source/drain extension composed of Si Ge" (emphasis added), the Appellant does not direct us to any facts (e.g., scope-limiting descriptions or definitions in the 6 Appeal2015-000117 Application 11/379,426 Specification) that compel an interpretation of the limitation "said NivIOS source/drain extension composed of SiGe" recited in claim 22 to exclude any element or material other than Si and Ge. Indeed, the Specification describes doped source/drain extensions broadly without any particular limitation (i-fi-f 5-9) and adds merely that "[ t ]he source/ drain extensions 90 are preferably made of Si Ge" (i-f 14) (emphasis added). Therefore, we conclude that the recitation "said NMOS source/drain extension composed of Si Ge" does not exclude unrecited elements, materials, or layers as being part of the NMOS source/drain extension. In any event, we find that Samoilov teaches, or would have reasonably suggested, a source/drain extension based solely on SiGe. Samoilov's Figure IA is reproduced as follows: 22 J1Yn1~ .-------r-13 c:;-....,.....o:;;r....._..:;;;.,,._~ 12 10 FIG. 1A 7 Appeal2015-000117 Application 11/379,426 Samoilov's Figure IA above depicts a ivIOSFET (metal oxide semiconductor field effect transistor) that may contain a PMOS component or an NMOS component, wherein a silicon-containing compound is deposited by epitaxial growth to the source/ drain features of the device (i-fi-f 26, 67---68). Samoilov's MOSFET is described as including a substrate 10, a source/drain layer 12, a silicon-containing layer 13 grown epitaxially on the source/drain 12, and a gate oxide layer 18 (i-f 27). As found by the Examiner (Ans. 2-3), Samoilov explicitly teaches that the silicon-containing layer 13, which corresponds to the Appellant's "source/drain extension," contains "at least silicon and may contain germanium, carbon, boron, arsenic and/or phosphorus" (i-f 24) (emphasis added). In addition, Samoilov discloses an embodiment in which "silicon containing film is epitaxially grown to produce a doped SiGe film" (i-f 50; see also i1i1 43, 48). Thus, although Samoilov indicates that "Si Ge grown epitaxially on the top of silicon has compressive stress inside the film because the lattice constant of Si Ge is larger than that of silicon" and "[fJor NMOS application, SiC can be used in the recessed areas to create tensile stress in the channel" (i-f 68) (emphasis added), the reference considered as a whole falls short of criticizing, discrediting, or otherwise discouraging an SiGe layer in the NMOS. In re Gurley, 27 F.3d 551, 553 (Fed. Cir. 1994) ("A known or obvious composition does not become patentable simply because it has been described as somewhat inferior to some other product for the same use."). We are also unpersuaded by the Appellant's argument that Yu "teaches away from the claimed invention by teaching that the source/drain extension is not composed of Si Ge" (Br. 12). Contrary to what the 8 Appeal2015-000117 Application 11/379,426 Appellant contends, Yu does not say that the source/drain extension cannot be composed of Si Ge. Rather, without placing any limitation on the type of silicon material that can be used as the source/drain extension, Yu discloses generally that NMOS or PMOS source/drain extensions implemented by a laser thermal annealing process-a technique disclosed as suitable in the current Specification (i-f 28}-provide even dopant distribution with abrupt junctions, resulting in super-doped source/drain extensions exhibiting improved device performance and control of short-channel effects (Abstract, Introduction, Device Fabrication, Summary, and Figures). Merely identifying the differences between Yu and claim 22 does not suffice to establish a teaching away. Here, as pointed out by the Examiner (Ans. 4), Yu was not cited for showing every limitation of the claim but rather for the teachings regarding the advantages of treating a super-doped Si-containing source/drain extension with a laser thermal process. In re Keller, 642 F.2d 413, 425 (CCPA 1981) (nonobviousness cannot be established merely by attacking references individually where the rejection is based on the collective teachings of multiple prior art references). Considering the collective teachings of Samoilov, Yu, and Essaian, which teaches that heat from laser annealing results in even distribution of germanium and dopant in a crystal lattice of silicon alloy (col. 3, 1. 65---col. 4, 1. 6), we detect no error in the Examiner's obviousness conclusion. We conclude, as did the Examiner, that a person having ordinary skill in the art would have reasonably expected that the implementation of Yu's technique to make Samoilov's NMOS source/drain extension based on SiGe would provide even dopant distribution at high dopant levels as well as highly abrupt junctions, thereby resulting in a device having the advantages 9 Appeal2015-000117 Application 11/379,426 described in Yu and including the disputed limitations of claim 22. KSR Int 'l Co. v. Teleflex Inc., 550 U.S. 398, 417 (2007) ("[I]f a technique has been used to improve one device, and a person of ordinary skill in the art would recognize that it would improve similar devices in the same way, using the technique is obvious unless its actual application is beyond his or her skill."). See also In re O'Farrell, 853 F.2d 894, 904 (Fed. Cir. 1988) (only a reasonable expectation of success-not absolute predictability-is required to establish obviousness). For these reasons, we uphold the Examiner's rejection of claim 22. II. Claims 23 & 24 Claim 23 depends from claim 22 and recites further that "said evenly distributed dopants of said PMOS source/drain extension are B with a concentration above 2xl 020 atoms/cc" (Br. 26). Claim 24 also depends from claim 22 and recites that "said evenly distributed dopants of said NMOS source/drain extension are P with a concentration above 4xl 020 atoms/cc" (id. at 27). Referring to certain portions of the references, the Appellant argues that each of the references "teaches away" from the specified dopant concentrations (id. at 14, 15). The Appellant is incorrect. As pointed out by the Examiner (Ans. 6--- 7), Samoilov, e.g., teaches the specified concentrations by disclosing a boron dopant concentration level ranging from about 1015 atoms/cm3 to about 1021 atoms/cm3 for p-type materials and P and/or As dopant concentration of about 1015 atoms/cm3 to about 1021 atoms/cm3 for p-type materials (i-f 48). Similarly, Yu also teaches dopant concentrations greater than 1021/cm3 (Introduction). 10 Appeal2015-000117 Application I 1/379,426 III. Claims 25 & 26 With respect to claims 25 and 26, the Appellant repeats many of the same arguments or arguments similar to those offered in support of claims 22-24 (Br. I6-I8). Therefore, we rely on the same or analogous reasons as those discussed above. IV. Claims 29 & 30 Claim 29 depends from claim 22 and recites that "a top surface of said NMOS source/drain extension is the same height as a bottom surface of said gate silicon oxide layer" (Br. 27). Claim 30 depends from claim 22 and recites that "a top surface of said PMOS source/drain extension is the same height as a bottom surface of said gate silicon oxide layer" (id.). The Appellant argues that none of the references teach the additional limitations of these claims (id. at I 8-2 I). In particular, the Appellant argues that Samoilov's Figure IA teaches away from the disputed limitations because Samoilov teaches epitaxially grown silicon, not SiGe (id. at I9, 20). As found by the Examiner (Ans. 9, IO), Samoilov's Figure IA shows that the top surface of silicon-containing layer I3 (i.e., either the PMOS or NMOS source/drain extension layer) is at the same height or level as the bottom surface of gate oxide layer I8. Regarding the Appellant's argument concerning the lack of Samoilov' s disclosure of Si Ge, we have explained in our discussion of claim 22 above why the argument is unpersuasive and, therefore, we incorporate it here. V. Claims 31 & 32 Claim 3 I depends from claim 22 and recites "a top surface of said NMOS source/drain extension is higher than a bottom surface of said gate silicon oxide layer" (Br. 28). Claim 32 also depends from claim 22 and 11 Appeal2015-000117 Application I 1/379,426 recites "a top surface of said PivIOS source/drain extension is higher than a bottom surface of said gate silicon oxide layer" (id.). The Appellant argues that Samoilov's Figure IA teaches away from the disputed limitations because Samoilov teaches epitaxially grown silicon, not SiGe (id. at 22-23). The Appellant's arguments are unpersuasive. The Examiner clarified in the Answer that Samoilov's Figure IB--not IA- discloses the disputed limitations (Ans. I I, I2). Samoilov's Figure IB shows the top of silicon- containing layer I 4 at a height or level above the bottom of gate oxide layer I8. Again, regarding the Appellant's argument concerning the lack of Samoilov' s disclosure of Si Ge, we have explained in our discussion of claim 22 above why the argument is unpersuasive and, therefore, we incorporate it here. SUMMARY The Examiner's decision to reject claims 22-26 and 29-32 is affirmed. No time period for taking any subsequent action in connection with this appeal may be extended under 37 C.F.R. § 1. I36(a)(l). AFFIRMED I2