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 claims 1 - 13 in the reply filed on 12/08/2025 is acknowledged.
Information Disclosure Statement
The information disclosure statement (IDS) was submitted on 10/17/2022. The submission is in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statement is being considered by the examiner.
Specification
The abstract of the disclosure is objected to because the abstract repeats information already present in the title of the application. The abstract states “Embodiments of the present invention provide a method of forming a MRAM structure.” And also states “An MRAM structure formed thereby is also provided.”. The title of the application already states “MRAM DEVICE STRUCTURE WITH IMPROVED TOP ELECTRODE” and the abstract should not repeat the use of MRAM structure. A corrected abstract of the disclosure is required and must be presented on a separate sheet, apart from any other text. See MPEP § 608.01(b).
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claim 7 - 13 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 7 states “…wherein the top electrode is horizontally larger than the second ferromagnetic layer and saddles on top of the second ferromagnetic layer…”. It is unclear what the term “saddles on top” means as used in the claim. The specification does not clarify the use of the term “saddles”. The specification only uses the term “saddle on top” in paragraph [0048] of the specification of the immediate invention. It is unclear if the terms “saddle” or “saddles” refers to the shape of the top electrode (as in the shape of a saddle or wherein there is a top point and two lower points on either side), if the use of the term saddle or saddles means to place a burden upon an object such as weight, stress, or other forces, or if the term saddles refers to the location horizontally larger part of the top electrode, and means that the horizontally larger part is both above or on the second ferromagnetic layer and on either side of the second ferromagnetic layer. As there are multiple interpretations of the term “saddles”, claim 7 is rejected as being indefinite. As claims 8 – 13 depend on claim 7, claims 8 – 13 inherit all of claim 7’s deficiencies and are rejected as being indefinite.
For the purpose of compact prosecution, examiner is interpreting claim 7 as using “saddles on top of the second ferromagnetic layer” to mean that the top electrode is both above and on two sides of the second ferromagnetic layer, as this interpretation appears closest to the specification and the drawings, and agrees with the rest of the claim wherein a bottom surface of the top electrode must also be below the top surface of the second ferromagnetic layer.
Claim Rejections - 35 USC § 102
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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.
(a)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention.
Claim(s) 1 – 4, 7 – 10, and 12 is/are rejected under 35 U.S.C. 102(a)(1) and (a)(2) as being anticipated by US 9601686 B1 hereinafter Annunziata.
For claim 1, Annunziata teaches “A MRAM structure comprising: a magnetic tunnel junction (MTJ) stack (fig. 1A – 1B, fig. 2E), the MTJ stack includes, from a bottom to a top thereof, a bottom electrode (fig. 2E numeral 101); a first ferromagnetic layer (fig. 2E numeral 105; fig. 1A numeral 102; Col. 2 ln 48 - 61); a tunnel barrier layer (fig. 2E numeral 105; fig. 1A numeral 103); a second ferromagnetic layer (fig. 2E numeral 105; fig. 1A numeral 104; Col. 2 ln 48 - 61); and a top electrode (fig. 2E numeral 206), wherein the top electrode has a first portion directly above the second ferromagnetic layer and a second portion vertically outside the second ferromagnetic layer, and a bottom surface of the first portion of the top electrode and a bottom surface of the second portion of the top electrode are at two different levels (fig. 2E shows top electrode 206 with a first portion with a first bottom surface directly over the second ferromagnetic layer 105, the layer 105 including ferromagnetic layers 102 and 104 as shown in figures 1A and 1B, and a second portion with a second bottom surface outside the second ferromagnetic layer, and wherein the two different bottom surfaces are at two different levels as shown in fig. 2E).” Examiner is interpreting the layers 102 and 104 in fig. 1A – 1B as ferromagnetic, as Annunziata teaches the layers including materials such as IrMN, CoFe, CoFeB, Ru, and other materials that are ferromagnetic.
For claim 2, Annunziata teaches “The MRAM structure of claim 1, wherein the second portion of the top electrode is separated from the second ferromagnetic layer by a dielectric liner (fig. 3E numeral 301).”
For claim 3, Annunziata teaches “The MRAM structure of claim 1, further comprising a dielectric liner (fig. 3E numeral 301), the dielectric liner lining a sidewall of the first ferromagnetic layer, a sidewall of the tunnel barrier layer, and a sidewall of the second ferromagnetic layer, the dielectric liner being directly above the bottom electrode (fig. 3E shows dielectric liner 301 on the sidewalls of the first ferromagnetic layer, tunnel barrier layer, and second ferromagnetic layer shown by numeral 105 and being directly above the bottom electrode 101).”
For claim 4, Annunziata teaches “The MRAM structure of claim 1, wherein the MTJ stack is surrounded by an interlevel-dielectric (ILD) layer (fig. 3D – 3E numeral 201), the ILD layer having one or more via holes (fig. 3D numeral 202) that are partially filled with part of the second portion of the top electrode (fig. 3E numeral 206).”
For claim 7, Annunziata teaches “A MRAM structure comprising: a magnetic tunnel (MTJ) stack (fig. 1A – 1B numeral 105; fig. 2E numeral 105), the MTJ stack comprises: a bottom electrode (fig. 2E numeral 101); a first ferromagnetic layer on top of the bottom electrode (fig. 2E numeral 105; fig. 1A numeral 102); a tunnel barrier layer on top of the first ferromagnetic layer (fig. 2E numeral 105; fig. 1A numeral 103); a second ferromagnetic layer on top of the tunnel barrier layer (fig. 2E numeral 105; fig. 1A numeral 104); and a top electrode (fig. 2E numeral 206), wherein the top electrode is horizontally larger than the second ferromagnetic layer (fig. 2E shows second electrode 206 horizontally larger than the second ferromagnetic layer included in layer 105) and saddles on top of the second ferromagnetic layer (fig. 2E shows top electrode 206 on top of the MJT stack 105 and on either side of the MTJ stack 105), the top electrode having a bottom surface and at least a portion of the bottom surface being below a level of a top surface of the second ferromagnetic layer (fig. 3E shows an embodiment in which the top electrode 206 has a bottom surface below the top surface of the MTJ stack 105, the top surface of the MTJ stack 105 being the second ferromagnetic layer as shown in figure 1A numeral 104).”
For claim 8, Annunziata teaches “The MRAM structure of claim 7, wherein the at least a portion of the bottom surface of the top electrode is horizontally separated from the second ferromagnetic layer by a dielectric liner (fig. 3E shows dielectric liner 205 horizontally separating the MTJ stack 105 from the top electrode 206; Col. 3 ln 37 – 46 teaches liner 205 as an electrically non-conductive material, such as tantalum nitride and other materials).”
For claim 9, Annunziata teaches “The MRAM structure of claim 7, wherein a sidewall of the first ferromagnetic layer, a sidewall of the tunnel barrier layer, and a sidewall of the second ferromagnetic layer are covered by the dielectric liner (fig. 3E shows the MTJ stack 105 having sidewalls covered by the dielectric liner 205), and the dielectric liner is vertically aligned with the bottom electrode (fig. 3E shows the dielectric liner 205 being above and aligned with the bottom electrode 101. The dielectric liner is not shown to be offset or not above the bottom electrode.).”
For claim 10, Annunziata teaches “The MRAM structure of claim 9, wherein the dielectric liner has a vertical height above the top surface of the second ferromagnetic layer (fig. 3E numeral 205 shows the dielectric liner above a top surface of the MTJ stack 105, which includes the second ferromagnetic layer 104 as shown in figure 1A – 1B), and a portion of the top electrode above the top surface of the second ferromagnetic layer is surrounded by the dielectric layer (fig. 3E shows dielectric liner 205 surrounding top electrode 206).”
For claim 12, Annunziata teaches “The MRAM structure of claim 7, wherein the first ferromagnetic layer is a reference layer, and the second ferromagnetic layer is a free layer (Col. 1 ln 11 – 22; Col. 2 ln 48 – Col. 3 ln 19).”
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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.
Claim(s) 5 and 11 is/are rejected under 35 U.S.C. 103 as being unpatentable over US 9601686 B1 hereinafter Annunziata in further view of US 20200217735 A1 hereinafter Mehta.
For claim 5, Annunziata teaches all of claim 1. Annunziata is silent regarding the top electrode being the same material composition as the bottom electrode.
Mehta teaches a magnetic tunnel junction structure (Mehta, fig. 2) with a top electrode (fig. 2 numeral 32) and a bottom electrode (fig. 2 numeral 16) and wherein the top electrode and the bottom electrode have the same composition (Par. [0039]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the immediate invention to combine the matching composition of electrodes in Mehta with the magnetic tunnel junction structure in Annunziata in order to ensure both ends of the device have similar conductivity and other properties by matching the materials and to simplify construction of the device by using similar deposition methods by having electrodes with the same compositions.
For claim 11, Annunziata teaches all of claim 7. Annunziata is silent regarding the top electrode comprising a material selected from a group consisting of tantalum-nitride (TaN) and titanium-nitride (TiN), and that the bottom electrode has a same material composition as the top electrode.
Mehta teaches a magnetic tunnel junction structure (Mehta, fig. 2) with a top electrode (fig. 2 numeral 32) and a bottom electrode (fig. 2 numeral 16) and wherein the top electrode and the bottom electrode have the same composition (Par. [0039]). Mehta also teaches that the electrode can comprise tantalum-nitride or titanium-nitride (Par. [0023]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the immediate invention to combine the materials in Mehta with the electrodes in Annunziata in order to select the desired conductivity of the device and other conductive properties dependent on the electrode materials. It has been held to be within the general skill of a worker in the art to select a known material on the basis of its suitability for the intended use as a matter of obvious design choice. In re Leshin, 125 USPQ 416 (CCPA 1960).
Claim(s) 6 is/are rejected under 35 U.S.C. 103 as being unpatentable over US 9601686 B1 hereinafter Annunziata in further view of US 20200321394 A1 hereinafter Hashemi.
For claim 6, Annunziata teaches all of claim 1. Annunziata is silent regarding the MRAM structure further comprising a bottom contact and a conductive cap between the bottom electrode and the bottom contact, wherein the bottom contact is a metal level of a back-end-of-line (BEOL) structure.
Hashemi teaches a MRAM structure (Hashemi, fig. 10) with a magnetic-tunnel-junction stack (fig. 10 numeral 31) with a bottom electrode (fig. 10 numeral 50), a bottom contact (fig. 10 numeral 20), and a conductive cap between the bottom electrode and the bottom contact (fig. 10 numeral 41), and wherein the bottom contact is a metal level of a back-end-of-line (BEOL) structure (Par. [0026]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the immediate invention to combine the bottom contact and conductive cap in Hashemi with the MJT structure and bottom electrode in Annunziata in order to protect the bottom electrode (Hashemi, Par. [0036]) and avoid excessive resistance increases (Hashemi, Par. [0053]).
Claim(s) 13 is/are rejected under 35 U.S.C. 103 as being unpatentable over US 9601686 B1 hereinafter Annunziata in further view of US 20210159270 A1 hereinafter Reznicek.
For claim 13, Annunziata teaches all of claim 7. Annunziata is silent regarding the MRAM structure including a top contact, the top contact having a flat bottom surface in contact with a top surface of the top electrode, wherein the top contact is a metal level of a back-end-of-line (BEOL) structure.
Reznicek teaches a MRAM structure (Reznicek, fig. 14A) with a magnetic tunnel junction stack (fig. 4A numeral 32P) with a top electrode (fig. 14A numeral 42P; Par. [0074]) and a top contact having a flat bottom surface in contact with the top surface of the top electrode (fig. 14A numeral 66Y; Par. [0100]), wherein the top contact is a metal level of a back-end-of-line (BEOL) structure (Par. [0098 – 0099]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the immediate invention to combine the top contact in Reznicek with the top electrode and magnetic tunnel junction stack in Annunziata in order to achieve a low wiring resistance and a fast memory speed (Reznicek, Par. [0101]).
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to JACOB T NELSON whose telephone number is (571)272-1031. The examiner can normally be reached Monday through Friday 9:00 AM to 5:00 PM.
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/J.T.N./Examiner, Art Unit 2815
/MONICA D HARRISON/Primary Examiner, Art Unit 2815