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.
Claim(s) 1-4 and 8 is/are rejected under 35 U.S.C. 103 as being unpatentable over van der Straten (US 20230189535 A1), in view of Chuang (US 20230189657 A1) and Nowak (US 20220199687 A1).
Regarding independent claim 1, van der Straten teaches a magnetic tunnel junction device, comprising: a bottom electrode (Fig. 4D, 106; [0052], "...the first conductive structure 106…"); and a magnetic tunnel junction pillar formed above the bottom electrode (Fig. 1L, 12; [0070], "...to form an MTJ pillar 12…"), wherein the magnetic tunnel junction pillar includes: a reference layer formed on top of the bottom electrode (Fig. 4D, 130; [0063], "The MTJ stack 10 may include at least a magnetic reference layer 130…"), a dielectric layer formed on top of the reference layer (Fig. 4D, 130, 140; [0069], "According to an embodiment, the hardmask layer 140 may be composed of a metal such as TaN, TaAlN, WN as the bottommost material, and a dielectric material such as silicon dioxide, silicon nitride, silicon carbide, and the like, as the topmost material."), and a tunnel barrier layer separating the reference layer from the free layer (Fig. 4B, 132, 130, 134; [0063], "The MTJ stack 10 may include at least a magnetic reference layer 130, a tunnel barrier layer 132, and a magnetic free layer 134 as depicted in the figure."), and a top electrode formed above the magnetic tunnel junction pillar (Fig. 4B, 165; [0080], "The second conductive structure 165 may be formed in the third dielectric layer 160 in accordance with typical techniques.").
However, van der Straten does not teach a free layer formed within the dielectric layer, and partially within a recessed area of the reference layer, and wherein a bottom surface and sidewall surfaces of the free layer are encased by the tunnel barrier layer.
However, in the same field of endeavor, Chuang teaches a free layer formed within the dielectric layer (Fig. 13, 132, 118C, 118A; [0027], "The MTJ film stack 118 is a multi-layer film stack that includes a reference layer 118A over the bottom electrode layer 116, a tunnel barrier layer 118B over the reference layer 118A, a free layer 118C over the tunnel barrier layer 118B...", [0048], "The first spacer layer 132A and the second spacer layer 132B may comprise dielectric materials, such as silicon oxide, silicon nitride, or the like."), and Nowak teaches and partially within a recessed area of the reference layer (Fig. 9, 85, 89; [0061], "...free layer 85, tunnel barrier 87 and reference layer 89…"), and wherein a bottom surface and sidewall surfaces of the free layer are encased by the tunnel barrier layer (Fig. 9, 85, 87, (The bottom (top in this image, but can be rotated) and sidewalls are clearly surrounded)).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to combine the magnetic tunnel junction device of van der Straten with the free layer in a dielectric layer of Chuang so as to "protect sidewalls of the free layer", (Chuang, [0010]), and with the free area in a recessed are of the reference layer and tunnel barrier layer so as to provide a "device with a good exchange or high magnetization while preserving low local magnetic fields at the edges of the funnel-like tube", (Nowak, [0026]).
Regarding dependent claim 2, van der Straten, as previously modified by Chuang and Nowak, teaches the magnetic tunnel junction device of claim 1, and Nowak further teaches wherein the bottom surface of the free layer is located below a top surface of the reference layer (Fig. 9, 81, 85, (The bottom (top in this image, but can be rotated) of the free layer 81 is below the top of the reference layer 85)).
Regarding dependent claim 3, van der Straten, as previously modified by Chuang and Nowak, teaches the magnetic tunnel junction device of claim 1, and Nowak further teaches wherein the tunnel barrier layer is conformally formed to completely cover the bottom surface and sidewall surfaces of the free layer (Fig. 9, 85, 87, (The bottom (top in this image, but can be rotated) and sidewalls are clearly surrounded)).
Regarding dependent claim 4, van der Straten, as previously modified by Chuang and Nowak, teaches the magnetic tunnel junction device of claim 1, and further teaches wherein the reference layer is formed using a subtractive manufacturing process ([0064], "The various material layers of the MTJ stack 10 can be formed by utilizing one or more deposition processes such as, for example, plating, sputtering, plasma enhanced atomic layer deposition (PEALD), plasma enhanced chemical vapor deposition (PECVD) or physical vapor deposition (PVD)."), and the free layer is formed using an additive manufacturing process ([0064], "The various material layers of the MTJ stack 10 can be formed by utilizing one or more deposition processes such as, for example, plating, sputtering, plasma enhanced atomic layer deposition (PEALD), plasma enhanced chemical vapor deposition (PECVD) or physical vapor deposition (PVD).").
Regarding dependent claim 8, van der Straten, as previously modified by Chuang and Nowak, teaches the magnetic tunnel junction device of claim 1, and further teaches further comprising a second dielectric encapsulation layer formed on sidewall surfaces of the tunnel barrier layer and the top electrode (Fig. 4B, 160; [0079], "Referring now to FIG. 1L, a cross-sectional view of the memory device 100 is shown after forming a dielectric filling layer or third dielectric layer 160…").
Claim(s) 5-7 and 9-11 is/are rejected under 35 U.S.C. 103 as being unpatentable over van der Straten (US 20230189535 A1), in view of Chuang (US 20230189657 A1), Nowak (US 20220199687 A1), and Dutta (US 20230217836 A1).
Regarding dependent claim 5, van der Straten, as previously modified by Chuang and Nowak, teaches the magnetic tunnel junction device of claim 1. However, as previously combined, they do not teach further comprising a first dielectric encapsulation layer formed on sidewall surfaces of the bottom electrode and the reference layer.
However, in the same field of endeavor, Dutta teaches further comprising a first dielectric encapsulation layer formed on sidewall surfaces of the bottom electrode and the reference layer (Fig. 11, 1015, 709, 711; [0054], "The encapsulation layer 1015 is preferably an insulator such as SiN, SiCN SiNO or SiC and surrounds the MTJ layer 711 as well as the hardmask 813 and bottom electrode layer 709.").
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to combine the magnetic tunnel junction device as described by the combination of van der Straten, Chuang, and Nowak with the dielectric encapsulation layer of Dutta so as to "to prevent oxygen or moisture diffusion from an interlayer dielectric (ILD) layer", (Dutta, [0054]).
Regarding dependent claim 6, van der Straten, as previously modified by Chuang, Nowak, and Dutta, teaches the magnetic tunnel junction device of claim 5. However, as previously combined, they do not teach further comprising a first interlayer dielectric layer formed within inter-pillar gaps located laterally adjacent to the first dielectric encapsulation layer, wherein the first interlayer dielectric layer laterally surrounds the first dielectric encapsulation layer formed on the sidewall surfaces of the bottom electrode and the reference layer.
However, Dutta further teaches further comprising a first interlayer dielectric layer formed within inter-pillar gaps located laterally adjacent to the first dielectric encapsulation layer, wherein the first interlayer dielectric layer laterally surrounds the first dielectric encapsulation layer formed on the sidewall surfaces of the bottom electrode and the reference layer (Fig. 11, 609; [0041], "In preferred embodiments, the dielectric capping layer 609 is a different dielectric than that used in substrate layer 605.").
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to combine the magnetic tunnel junction device as described by the combination of van der Straten, Chuang, Nowak, and Dutta with the interlayer dielectric layer of Dutta so as to encapsulate "the bottom electrode contact", (Dutta, [0043]).
Regarding dependent claim 7, van der Straten, as previously modified by Chuang, Nowak, and Dutta, teaches the magnetic tunnel junction device of claim 6, and Dutta further teaches wherein the first dielectric encapsulation layer and the first interlayer dielectric layer are formed from compositionally different dielectric materials (Fig. 11, 609; [0041], "In preferred embodiments, the dielectric capping layer 609 is a different dielectric than that used in substrate layer 605.").
Regarding dependent claim 9, van der Straten, as previously modified by Chuang and Nowak, teaches the magnetic tunnel junction device of claim 8. However, as previously combined, they do not teach further comprising a second interlayer dielectric layer formed within inter-pillar gaps located laterally adjacent to the second dielectric encapsulation layer, wherein the second interlayer dielectric layer laterally surrounds the second dielectric encapsulation layer formed on the sidewall surfaces of the tunnel barrier layer and the top electrode.
However, in the same field of endeavor, Dutta teaches further comprising a second interlayer dielectric layer formed within inter-pillar gaps located laterally adjacent to the second dielectric encapsulation layer, wherein the second interlayer dielectric layer laterally surrounds the second dielectric encapsulation layer formed on the sidewall surfaces of the tunnel barrier layer and the top electrode (Fig. 11, 1117, 1015; [0054], "The function of the encapsulation layer 1015 is to prevent oxygen or moisture diffusion from an interlayer dielectric (ILD) layer 1117 (shown in FIG. 11) to the MTJ layer 711.").
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to combine the magnetic tunnel junction device as described by the combination of van der Straten, Chuang, and Nowak with the interlayer dielectric layer of Dutta so as to "to prevent oxygen or moisture diffusion from an interlayer dielectric (ILD) layer", (Dutta, [0054]).
Regarding dependent claim 10, van der Straten, as previously modified by Chuang, Nowak, and Dutta, teaches the magnetic tunnel junction device of claim 9, and Dutta further teaches wherein the second dielectric encapsulation layer and the second interlayer dielectric layer are formed from compositionally different dielectric materials ([0054], "The encapsulation layer 1015 is preferably an insulator such as SiN, SiCN SiNO or SiC…", [0055], "Examples of materials that can be used to form the ILD layer 1117 include, but are not limited to, SiO2, low-k dielectric materials, ULK dielectric material and TEOS.").
Regarding dependent claim 11, van der Straten, as previously modified by Chuang and Nowak, teaches the magnetic tunnel junction device of claim 1. However, as previously combined, they do not teach wherein the tunnel barrier layer is further formed between the dielectric layer and the top electrode.
However, in the same field of endeavor, Dutta teaches wherein the tunnel barrier layer is further formed between the dielectric layer and the top electrode (Fig. 11, 711; [0044], "Although depicted as a single memory layer 711, memory stacks in MRAM elements are usually formed from two ferromagnetic plates, each of which can hold a magnetic polarization, separated by a thin insulating layer called the tunnel barrier layer.").
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to combine the magnetic tunnel junction device as described by the combination of van der Straten, Chuang, and Nowak with the barrier layer position of Dutta so as "to protect [the] dielectric layer", (Dutta, [0029]).
Claim(s) 12 and 13 is/are rejected under 35 U.S.C. 103 as being unpatentable over van der Straten (US 20230189535 A1), in view of Chuang (US 20230189657 A1), Nowak (US 20220199687 A1), Dutta (US 20230217836 A1), and Lin (US 9525126 B1).
Regarding dependent claim 12, van der Straten, as previously modified by Chuang, Nowak, and Dutta, teaches the magnetic tunnel junction device of claim 11. However, as previously combined, they do not teach wherein a top surface of the free layer is substantially coplanar with a top surface of the tunnel barrier layer formed between the dielectric layer and the top electrode.
However, in the same field of endeavor, Lin teaches wherein a top surface of the free layer is substantially coplanar with a top surface of the tunnel barrier layer formed between the dielectric layer and the top electrode (Fig. 6A, 301, 401, 305; (Col. 8-9, Lines 67-6), "That is, the polished upper surfaces of the tunnel layer 301, fixed layer 302, optional AFM layer 303, optional buffer layer 304 and the first electrodes 305 and the polished upper surfaces of the free layer 401, optional buffer layer 402 and second conductive material 403 are substantially flush with the polished upper surface of the second dielectric layer 200b″.").
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to combine the magnetic tunnel junction device as described by the combination of van der Straten, Chuang, Nowak, and Dutta with the coplanar surfaces of Lin so as to achieve "a global planar surface across the substrate", (Lin, Col. 8, Lines 66-67).
Regarding dependent claim 13, van der Straten, as previously modified by Chuang, Nowak, Dutta, and Lin, teaches the magnetic tunnel junction device of claim 12, and further teaches wherein the top electrode is formed on the top surface of the free layer and the top surface of the tunnel barrier layer (Fig. 4D, 165; [0080], "The second conductive structure 165 may be formed in the third dielectric layer 160 in accordance with typical techniques.").
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
US 20230154513 A1,.
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/TIMOTHY JAMES MATTABONI/Examiner, Art Unit 2897 /CHAD M DICKE/Supervisory Patent Examiner, Art Unit 2897
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