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 .
Election/Restrictions
Applicant’s election without traverse of Group I, claims 1-15, in the reply filed on 01/23/2026 is acknowledged.
Claim Rejections - 35 USC § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claims 1-3,7,9-10,14 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by U.S. Patent Application Publication Number 2021/0005807 A1 to Kwon, “Kwon”.
Regarding claim 1, Kwon discloses a magnetoresistive random access memory (MRAM) (e.g. FIG. 10), comprising:
a pillar structure (structure including 135,175,187) having:
a bottom electrode (135, ¶ [0045]);
a magnetic tunnel junction (MTJ) (175, ¶ [0045]) having a reference layer (145), a free layer (165) and a tunnel barrier (155) disposed between the reference layer (145) and the free layer (165), the MTJ (175) disposed on the bottom electrode (135); and
a top electrode (187, ¶ [0041]-[0055]) disposed on the MTJ, the top electrode including at least two tiers (187a, 187b, 187c) wherein each tier successively includes a smaller footprint (as pictured due to etching together in FIGs. 7-8).
Regarding claim 2, Kwon discloses the MRAM as recited in claim 1, and Kwon further discloses (as evidenced by the etching step in FIG. 7 to FIG. 8) wherein one tier of the top electrode (any of 187a, 187b, 187c), the tunnel barrier (155) and the bottom electrode (135) share a same footprint (since being etched using the top electrode as an etch mask).
Regarding claim 3, Kwon discloses the MRAM as recited in claim 1, and Kwon further discloses wherein the top electrode includes three tiers (187a, 187b, 187c).
Regarding claim 7, Kwon discloses the MRAM as recited in claim 1, and Kwon further discloses wherein the top electrode (187a, 187b, 187c) includes (e.g. FIG. 8) etched corners (on 187b and 187c) to provide rounded or tapered features (as pictured).
Regarding claim 9, Kwon discloses a magnetoresistive random access memory (MRAM) (e.g. FIG. 10), comprising:
a pillar structure (structure including 135,175,187) having:
a bottom electrode (135, ¶ [0045]);
a magnetic tunnel junction (MTJ) (175, ¶ [0045]) having a reference layer (145), a free layer (165) and a tunnel barrier (155) disposed between the reference layer (145) and the free layer (165), the MTJ (175) disposed on the bottom electrode (135); and
a top electrode (187, ¶ [0041]-[0055]) disposed on the MTJ, the top electrode including three tiers (187a, 187b, 187c) wherein each tier is centered over the bottom electrode and successively includes a smaller footprint than a tier upon which each tier rests (as pictured due to etching together in FIGs. 7-8).
Regarding claim 10, Kwon discloses the MRAM as recited in claim 9, and Kwon further discloses wherein one tier (187a) of the top electrode, the tunnel barrier (155) and the bottom electrode (135) share a same footprint (due to being etched together in FIG. 8).
Regarding claim 14, Kwon discloses the MRAM as recited in claim 9, and Kwon further discloses wherein the top electrode (187a, 187b, 187c) includes (e.g. FIG. 8) etched corners (on 187b and 187c) to provide rounded or tapered features (as pictured).
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.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claims 4,5,11,12 are rejected under 35 U.S.C. 103 as being unpatentable over U.S. Patent Application Publication Number 2021/0005807 A1 to Kwon, “Kwon”, in view of U.S. Patent Application Publication Number 2022/0393101 A1 to Lee et al., “Lee”.
Regarding claims 4 and 11, although Kwon discloses the MRAM as recited in claims 3 and 11, Kwon fails to clearly teach wherein materials for the three tiers include TaN, WCN and TiN.
Lee teaches wherein an electrode (502) to an MRAM MTJ (112, ¶ [0073]) may include TaN or WCN or TiN or any combination of the foregoing (¶ [0074]).
It would have been obvious before the effective filing date of the claimed invention to one having ordinary skill in the art to have formed the device of Kwon by selecting the materials as claimed for the electrode as taught by Lee in order to select suitable electrode materials for an MRAM MTJ and since it has been held that the selection of a known material based on its suitability for its intended use supported a prima facie obviousness determination in Sinclair & Carroll Co. v. Interchemical Corp., 325 U.S. 327, 65 USPQ 297 (1945), In re Leshin, 277 F.2d 197, 125 USPQ 416 (CCPA 1960), and MPEP 2144.07 Art Recognized Suitability for an Intended Purpose, and/or since it has been held in KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 415-421, 82 USPQ2d 1385, 1395-97 (2007) that exemplary rationales that may support a conclusion of obviousness include:
(A) Combining prior art elements according to known methods to yield predictable results;
(B) Simple substitution of one known element for another to obtain predictable results;
(C) Use of known technique to improve similar devices (methods, or products) in the same way;
(D) Applying a known technique to a known device (method, or product) ready for improvement to yield predictable results;
(E) “Obvious to try” – choosing from a finite number of identified, predictable solutions, with a reasonable expectation of success;
(F) Known work in one field of endeavor may prompt variations of it for use in either the same field or a different one based on design incentives or other market forces if the variations are predictable to one of ordinary skill in the art;
(G) Some teaching, suggestion, or motivation in the prior art that would have led one of ordinary skill to modify the prior art reference or to combine prior art reference teachings to arrive at the claimed invention,
wherein in the instant case one having ordinary skill in the art could have and would have found it obvious to (E ) “Obvious to try” the selection of claimed electrode materials as taught by the teachings of materials of Lee with the predictable result of a suitable MTJ electrode material with a reasonable expectation of success.
Regarding claims 5 and 12, although Kwon discloses the MRAM as recited in claims 3 and 11, Kwon fails to clearly teach wherein materials for the three tiers include WN, MoN and Mo.
Lee teaches wherein an electrode (502) to an MRAM MTJ (112, ¶ [0073]) may include WN, MoN, (¶ [0074]) and Mo (¶ [0041]) and any combination of the foregoing.
It would have been obvious before the effective filing date of the claimed invention to one having ordinary skill in the art to have formed the device of Kwon by selecting the materials as claimed for the electrode as taught by Lee in order to select suitable electrode materials for an MRAM MTJ and since it has been held that the selection of a known material based on its suitability for its intended use supported a prima facie obviousness determination in Sinclair & Carroll Co. v. Interchemical Corp., 325 U.S. 327, 65 USPQ 297 (1945), In re Leshin, 277 F.2d 197, 125 USPQ 416 (CCPA 1960), and MPEP 2144.07 Art Recognized Suitability for an Intended Purpose, and/or since it has been held in KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 415-421, 82 USPQ2d 1385, 1395-97 (2007) that exemplary rationales that may support a conclusion of obviousness include:
(A) Combining prior art elements according to known methods to yield predictable results;
(B) Simple substitution of one known element for another to obtain predictable results;
(C) Use of known technique to improve similar devices (methods, or products) in the same way;
(D) Applying a known technique to a known device (method, or product) ready for improvement to yield predictable results;
(E) “Obvious to try” – choosing from a finite number of identified, predictable solutions, with a reasonable expectation of success;
(F) Known work in one field of endeavor may prompt variations of it for use in either the same field or a different one based on design incentives or other market forces if the variations are predictable to one of ordinary skill in the art;
(G) Some teaching, suggestion, or motivation in the prior art that would have led one of ordinary skill to modify the prior art reference or to combine prior art reference teachings to arrive at the claimed invention,
wherein in the instant case one having ordinary skill in the art could have and would have found it obvious to (E ) “Obvious to try” the selection of claimed electrode materials as taught by the teachings of materials of Lee with the predictable result of a suitable MTJ electrode material with a reasonable expectation of success.
Claims 8 and 15 are rejected under 35 U.S.C. 103 as being unpatentable over U.S. Patent Application Publication Number 2021/0005807 A1 to Kwon, “Kwon”, in view of U.S. Patent Number 6,965,138 B2 to Nakajima et al., “Nakajima”.
Regarding claims 8 and 15, Kwon discloses the MRAM as recited in claims 7 and 14, and although Kwon details the tapering and/or rounding of the corners (Kwon ¶ [0050]-[0052]) and the angle of the etching process (Kwon ¶ [0047]), Kwon fails to clearly anticipate wherein the etched corners include tapers having an angle of between 15 and 30 degrees with a vertical reference.
Nakajima teaches controlling the angle of the etching process (FIG. 6A-6C, column 12 lines 1-30) and teaches wherein an angle (e.g. FIG. 4B angle θt, FIG. 9A-9C, FIG. 11A) of an upper electrode (hard mask 36 forms the upper electrode over MTJ element 30) having an angle of 30 degrees with a vertical reference (FIG. 11A, column 15 lines 41-44, 70° with horizontal reference yields 20° with a vertical reference since 90° - 70° = 20°, or 30° since 90° - 60° = 30° column 21 lines 58-67).
It would have been obvious before the effective filing date of the claimed invention to one having ordinary skill in the art to have formed the device of Kwon with at least one of the sidewall tapers having an angle within the claimed range by using the etching process as taught by Nakajima in order to ensure that residual films are not formed thereby reducing the number of short circuit initial defects (Nakajima column 3 lines 1-20, column 19 lines 10-22, column 21 lines 15-31) and since it has been held that “where the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955), In re Hoeschele, 406 F.2d 1403, 160 USPQ 809 (CCPA 1969), wherein in the instant case the sidewall taper determines the degree of contaminate removed (Najajima column 21 lines 58-67) thereby making it a result effective variable, In re Antonie, 559 F.2d 618, 195 USPQ 6 (CCPA 1977), and MPEP 2144.05 Obviousness of Ranges II. OPTIMIZATION OF RANGES A. Optimization Within Prior Art Conditions or Through Routine Experimentation B. Only Result-Effective Variables Can Be Optimized.
Allowable Subject Matter
Claims 6 and 13 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.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to ERIC A WARD whose telephone number is (571)270-3406. The examiner can normally be reached M-F 10-6 ET.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Matthew Landau can be reached at (571)272-1731. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/Eric A. Ward/ Primary Examiner, Art Unit 2891