DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claims 1-3 and 11 are rejected under 35 U.S.C. 103 as being unpatentable over Renn (United States Patent Application Publication No. US 2011/0227145 A1, hereinafter “Renn”) in view of Cheng et al. (United States Patent Application Publication No. US 2018/0286977 A1, hereinafter “Cheng”) and further in view of Son et al. (United States Patent Application Publication No. US 2010/0224923 A1, hereinafter “Son”) and further in view of Iwamatsu et al. (United States Patent Application Publication No. US 2011/0031552 A1, hereinafter “Iwamatsu”).
In reference to claim 1, Renn discloses a similar device. Fig. 1-7 of Renn discloses a semiconductor memory device which comprises a bit line (20) extended in a first direction (X-direction) on a substrate (10). A first word line (52) extends in a second direction (Y-direction) on the bit line (20). Fig. 1 of Renn shows a single memory cell as part of an array; it is understood that there are additional identical memory cells to the left and right of the fig. 1 memory cell along the X-direction. Therefore there is a second word line (52) extended in the second direction (Y-direction) on the bit line (20) and spaced apart from the first word line (52) in the first direction (X-direction). A back gate electrode (54) is between the first word line (52) and the second word line (52) and is extended in the second direction (Y-direction). A first active pattern (10a) is between the first word line (52) and the back gate electrode (54) on the bit line (20). A second active pattern (10b) is between the first word line (52) and the back gate electrode (54) on the bit line (20).
Renn does not disclose that the back gate electrode includes a first region comprising a first conductive material and a second region comprising a second conductive material different from the first conductive material, and the first region of the back gate electrode is between the second region of the back gate electrode and the bit line. However fig. 8 of Cheng discloses a back gate electrode stack (808) which has a first lower region with a stack of at least two work function metal layers since Cheng discloses (emphasis added - p. 5, paragraph 52), “Non-limiting examples of suitable work function metals include p-type work function metal materials and n-type work function metal materials. P-type work function materials include compositions such as ruthenium, palladium, platinum, cobalt, nickel, and conductive metal oxides, or any combination thereof. N-type metal materials include compositions such as hafnium, zirconium, titanium, tantalum, aluminum, metal carbides (e.g., hafnium carbide, zirconium carbide, titanium carbide, and aluminum carbide), aluminides, or any combination thereof.” Cheng further discloses that the back gate electrode stack (808) includes a second upper region comprising a second conductive material in the form of a conductive gate metal which comprises aluminum (Al), platinum (Pt), gold (Au), tungsten (W), titanium (Ti), or any combination thereof (p. 5, paragraph 53). The second conductive material (conductive gate metal) is formed over the stack of at least two work function metal layers and is different from the first conductive material of either of the at least two work function metal layers. Cheng discloses that using a back gate electrode with a structure different from the front gate allows different voltages to be applied to the back gate and front gate electrodes which provides the benefit of tuning the characteristics of the device (p. 6, paragraph 57). In view of Cheng, it would therefore be obvious to implement a back gate electrode which includes a first region comprising a first conductive material and a second region comprising a second conductive material different from the first conductive material. In the device of Renn constructed in view of Cheng, the uppermost layer of the work function metal layer stack is the first region of the back gate electrode while the conductive gate metal forms the second region of the back gate electrode; the first region of the back gate electrode is between the second region of the back gate electrode and the bit line (20 – fig. 1-7 of Renn).
Fig. 1 of Renn does not show that the first word line/gate (52) comprises a first portion and a second portion that are alternately arranged in the second direction (Y-direction), and a width of the first portion of the first word line in the first direction is less than a width of the second portion of the first word line in the first direction. However fig. 18A of Son discloses the use of comb shaped gates (18b – leftmost or center) that have a width in the y-direction/first direction. The gates (18b – leftmost or center) extend along the x-direction/second direction. The thinnest portions of the gate (18b) facing the active pillars (11b) in the y-direction/first direction are the first portions while the portions between these thinnest portions are the second portions. The first portions and the second portions of the gate (18b) are alternately arranged in the x-direction/second direction. Each of the first portions has a smaller width than each of the widths of the second portions in the y-direction/first direction. Son discloses that surrounding the active pillar with a gate maximizes the channel area and increases the amount of current in the transistor (p. 3, paragraph 62). Iwamatsu discloses that increasing the channel area and current is desirable in the art (p. 1, paragraphs 6 and 8). In view of Son and Iwamatsu, it would therefore obvious to implement a first word line which comprises first and second portions that are alternately arranged in the second direction such that a width of the first portion in the first direction is less than a width of the second portion in the first direction in the device of Renn constructed in view of Cheng.
With regard to claim 2, in the device of Renn constructed in view of Cheng, Son, and Iwamatsu, the first region of the back gate electrode is a first electrode pattern of the first conductive material (work function metal), and the second region of the back gate electrode is a second electrode pattern of the second conductive material (conductive gate metal).
In reference to claim 3, in the device of Renn constructed in view of Cheng, Son, and Iwamatsu, the lowermost layer of the work function metal layer stack forms a third region between the uppermost layer of the work function metal layer (that forms the first region) and the bit line. The third region of the back gate electrode comprises a third conductive material different from the first conductive material.
With regard to claim 11, in the device of Renn constructed in view of Cheng, Son, and Iwamatsu, the first active pattern (10a – fig. 1-7 of Renn) is between a pair of the second portions of the first word line (52), wherein the pair of the second portions of the first word line (52) are adjacent to each other in the second direction (Y-direction).
Claim 9 is rejected under 35 U.S.C. 103 as being unpatentable over Renn in view of Cheng and further in view of Son and further in view of Iwamatsu as applied to claim 1 above and further in view of Cheng.
In reference to claim 9, Renn does not disclose that the first and second word lines (52) each comprises a first word line material layer comprising a third conductive material and a second word line material layer comprising a fourth conductive material different from the third conductive material.
However Cheng discloses the known use of two different gate metal material layers, which include a combination of aluminum, platinum, gold, tungsten, or titanium, as a gate electrode material (p. 3, paragraph 36). The applicant is reminded in this regard that it has been held that the selection of a known material based on its suitability for its intended use would be entirely obvious. See Sinclair & Carroll Co. v. Interchemical Corp., 325 U.S. 327, 65 USPQ 297 (1945) ("Reading a list and selecting a known compound to meet known requirements is no more ingenious than selecting the last piece to put in the last opening in a jig-saw puzzle." 325 U.S. at 335, 65 USPQ at 301.). See also In re Leshin, 277 F.2d 197, 125 USPQ 416 (CCPA 1960) (selection of a known plastic to make a container of a type made of plastics prior to the invention was held to be obvious). See MPEP 2144.07. In view of the above, it would therefore be obvious to implement each of the first and second word lines (52) with a stack of two different metal layers with one metal layer being the third conductive material and the second metal layer being the fourth conductive material.
Allowable Subject Matter
Claims 12-20 were allowed in the previous Office action.
Claims 4-8 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
The following is a statement of reasons for the indication of allowable subject matter: the reasons for the allowability of claims 12 and 16 were discussed in the previous Office action. Although claim 1 has been amended, the reasons for the allowability for the subject matter in claim 4 that were discussed in the previous Office action remain the same.
Response to Arguments
Applicant’s arguments, see p. 9-12, filed April 9, 2026, with respect to the rejections of claim 10 (now canceled) under 35 U.S.C. 103 and claim 11 under 35 U.S.C. 112 have been fully considered and are persuasive. Therefore, the rejections have been withdrawn.
However, upon further consideration, a new ground(s) of rejection is made in view of new references Son et al. (US 2010/0224923 A1) and Iwamatsu et al. (US 2011/0031552 A1) which address the added first word line limitations to claim 1, which were originally in claim 10 (now canceled).
With regard to claim 11, the specific remarks (p. 9 of the response) concerning the word, “adjacent,” have been found to be persuasive.
Conclusion
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/KEVIN QUINTO/Examiner, Art Unit 2893
/Britt Hanley/Supervisory Patent Examiner, Art Unit 2893
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