Ex Parte Cho et al

Patent Trial and Appeal BoardJan 23, 2014

11822548 (P.T.A.B. Jan. 23, 2014)

UNITED STATES PATENT AND TRADEMARK OFFICE ____________ BEFORE THE PATENT TRIAL AND APPEAL BOARD ____________ Ex parte BYUNG-KYU CHO, SE-HOON LEE, KYU-CHARN PARK, and CHOONG-HO LEE ____________ Appeal 2012-006550 Application 11/822,548 Technology Center 2800 ____________ Before JEAN R. HOMERE, CARLA M. KRIVAK, and DANIEL N. FISHMAN, Administrative Patent Judges. KRIVAK, Administrative Patent Judge. DECISION ON APPEAL Appellants appeal under 35 U.S.C. § 134(a) from a final rejection of claims 1-4, 6-10, 12, 14, 18-25, and 71-85. We have jurisdiction under 35 U.S.C. § 6(b). We reverse. Appeal 2012-006650 Application 11/822,548 2 STATEMENT OF THE CASE Appellants’ claimed invention is directed to a method of fabricating and employing a semiconductor memory device (Spec. ¶ [0002]). Independent claim 1, reproduced below, is illustrative of the subject matter on appeal. 1. A semiconductor memory device, comprising: a semiconductor substrate having projecting portions; a tunnel insulation layer formed over at least one of the projecting semiconductor substrate portions; a floating gate structure disposed over the tunnel insulation layer, an upper portion of the floating gate structure being wider than a lower portion of the floating gate structure, and the lower portion of the floating gate structure having a width less than a width of the tunnel insulating layer; first insulation layer portions formed in the semiconductor substrate and projecting from the semiconductor substrate such that the floating gate structure is disposed between the projecting first insulation layer portions; a dielectric layer formed over the first insulation layer portions and the floating gate structure; and a control gate formed over the dielectric layer, wherein the upper portion of the floating gate structure is formed of a different material than the lower portion of the floating gate structure. REFERENCES and REJECTIONS The Examiner rejected claims 1, 6-10, 12, 14, 18, 19, 22, 71, 80, and 83 under 35 U.S.C. § 103(a) based upon the teachings of Kang (US Appeal 2012-006650 Application 11/822,548 3 2002/0072197 A1, June 13, 2002) and Choi (US 2006/0094191 A1, May 4, 2006). The Examiner rejected claims 2, 3, 24, 25, 81, and 82 under 35 U.S.C. § 103(a) based upon the teachings of Kang, Choi, and Ozawa (US 2004/0238881 A1, Dec. 2, 2004). The Examiner rejected claim 4 under 35 U.S.C. § 103(a) based upon the teachings of Kang, Choi, and Mei (US 7,161,838 B2, Jan. 9, 2007). The Examiner rejected claims 20 and 21 under 35 U.S.C. § 103(a) based upon the teachings of Kang, Choi, and Ahn (US 7,700,989 B2, Apr. 20, 2010, filed Dec. 1, 2006). The Examiner rejected claim 23 under 35 U.S.C. § 103(a) based upon the teachings of Kang, Choi, and Lee (US 2006/0231900 A1, Oct. 19, 2006). The Examiner rejected claims 72 and 73 under 35 U.S.C. § 103(a) based upon the teachings of Kang, Choi, and Takiar (US 7,485,501 B2, Feb. 3, 2009, filed Nov. 2, 2005). The Examiner rejected claims 74-79, 84, and 85 under 35 U.S.C. § 103(a) based upon the teachings of Kang, Choi, and Shaw (US 5,611,038, Mar. 11, 1997). ANALYSIS The Examiner finds Kang discloses all the limitations of claims 1, 6-8, and 71 except for an upper portion of a floating gate structure formed of a material different from a lower portion of the floating gate structure (Ans. 5). The Examiner then relies on Choi for teaching this feature (Ans. 6). Appellants assert Kang discloses the same material for the upper and lower portions of the floating gate structure, as does Choi (App. Br. 23). Appeal 2012-006650 Application 11/822,548 4 Particularly, Appellants assert Choi discloses several alternative materials may be used to form a floating gate, and Kang discloses only using silicon for the floating gate (App. Br. 23). Thus, even if Kang and Choi could be combined, a floating gate having an upper portion formed of a material different from the lower portion would not result (App. Br. 23-25). We agree. Kang discloses a floating gate formed only of silicon and Choi discloses a floating gate formed of one material. The Examiner cites Choi’s paragraph 32 for teaching a conductive material layer 14 (floating gate) formed of various materials such as titanium, titanium nitride, aluminum, aluminum nitride, etc., or “combinations thereof.” Ans. 14. The Examiner incorrectly interprets the phrase “combinations thereof” to mean the conductive material layer can have a first portion made of one material and a second portion made of a different material, and thus finds “Choi teaches suitable alternative materials for floating gates, including polysilicon, titanium, and combinations thereof.” Id. (emphasis omitted). Rather, Choi only discloses the same material for use in a floating gate; the material can include combinations of various materials, not separate materials for each layer. Thus, we agree with Appellants neither Kang nor Choi, alone or in combination, teaches or suggests the “upper portion of the floating gate structure is formed of a different material than the lower portion of the floating gate structure” as recited in claim 1. Because Appellants have shown at least one error in the Examiner’s rejection, we conclude the Examiner erred in finding the combination of Kang and Choi teaches or suggests Appellants’ claimed invention, and we do not sustain the Examiner’s rejection of claim 1. We similarly do not sustain the Examiner’s Appeal 2012-006650 Application 11/822,548 5 rejection of independent claims 24, 25, 71, 74, and 79, argued for the same reasons (see App. Br. 22, 34, and 37). With respect to claims 2-4, 6-10, 12, 14, 19-23, 72, 73, 75-78, and 80- 85, these claims depend from independent claims 1, 24, 25, 71, 74, and 79, and thus the Examiner’s rejection is also not sustained for the reasons set forth above. We also agree the Examiner erred in finding the limitation of claim 18, separately argued in the Appeal Brief and Reply Brief, is taught by Kang. As Appellants assert, Kang’s paragraph [0079] and Table 1 do not teach or suggest the limitation that “a width of the lower portion of the floating gate structure is no more than 10% less than a width of the upper portion of the floating gate structure” (App. Br. 27-28; Reply Br. 2-4). DECISION The Examiner’s decision rejecting claims 1-4, 6-10, 12, 14, 18-25, and 71-85 under 35 U.S.C. § 103 is reversed. REVERSED tj