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 § 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 20 is 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.
The scope of claim 20 is unclear because the final portion of the claims recites two conditional embodiments directed to different target materials (oxide and silicon germanium) that are connected by the phrases “or a combination thereof” and “and/or,” resulting in ambiguity as to which target material and associated parameters are required in a single method.
In particular, claim 20 recites a first set of process parameters when the target material comprises an oxide material (including a hydrogen to fluorine ratio greater than or about 3:1), a second set of process parameters when the target material comprises germanium (including a hydrogen to fluorine ratio greater than or about 3:1). However, the use of “and/or” between these embodiments make it unclear whether the claim requires: (1) the oxide embodiment only, (2) the silicon germanium embodiment only, (3) both embodiments in a single method, or (4) some unspecified combination of parameters from each embodiment.
Additionally, the repeated use of “or a combination thereof” within each embodiment further obscures the metes and bounds of the claim because it is unclear which combinations of parameters are encompassed, particularly in view of the differing hydrogen to fluorine ratio limitations.
Accordingly, one of ordinary skill in the art would not be reasonably apprised of the scope of claim 20.
Notwithstanding the indefiniteness noted above, the prior art rejections set forth below are presented based on a reasonable interpretation of claim 20 as encompassing either the oxide embodiment or the silicon germanium embodiment independently.
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.
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.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1 and 6 are rejected under 35 U.S.C. 103 as being unpatentable over Nguyen (US 2019/0326098 A1) in view of Takahashi (US 2008/0025899 A1).
Regarding claim 1, Nguyen teaches a method of etching substrate in a semiconductor processing chamber 178 (paragraphs [0005], [0031]. Nguyen further teaches flowing one or more plasma precursors through a microwave applicator 142 into a remote plasma region of a semiconductor processing chamber 178 (paragraphs [0031],[0051]). Nguyen further teaches generating a remote plasma within the remote plasma region at a microwave frequency, thereby forming plasma effluents 196 from the plasma precursors (paragraphs [0029], [0051]). Nguyen also teaches flowing the plasma effluents 196 into a processing region 589 of the semiconductor processing chamber 178 (paragraphs [0031], [0066]). Nguyen also teaches that the microwave applicator 142 comprises a resonator body/cavity 353/363 made of a first dielectric material and a dielectric window/plate 150 made up of a second dielectric material (paragraph [0051]).
However, Nguyen does not teach the generated remote plasma with an ion energy of less than or about 50 eV or a density greater than 1 x 1010 per cm3.
Takahashi teaches generating a remote plasma wherein the remote plasma comprises a density about greater than 1 x 1010 – 5 x 1012/cm3 and an ion energy greater than about 5.3 eV (paragraphs [0012], [0035]).
It would have been obvious to one of ordinary skill in the art before the effective date of the claimed invention to operate the microwave applicator plasma system of Nguyen with plasma parameters within the ranges taught by Takahashi, including plasma densities within the claimed range (greater than 1 x 1010 per cm3) and ion energy within the claimed range (less than or about 50 eV), in order to obtain plasma conditions suitable for semiconductor processing. It has been held that obviousness exists where the claimed ranges overlap or lie inside ranges disclosed by prior art. See MPEP 2144.05(I).
Regarding claim 6, Nguyen teaches all the limitations of claim 1 including that the first dielectric material comprises aluminum oxide (paragraph [0051]).
Claims 2, 4, 5 are rejected under 35 U.S.C. 103 as being unpatentable over Nguyen in view of Takahashi, as applied to claim 1 above, and further in view of Berry, III et al. (US 2016/0196969 A1).
Nguyen and Takahashi teach the limitations of claim 1 including generating a remote plasma within a remote plasma region of a semiconductor processing chamber and flowing plasma effluents into a processing region to perform an etching process.
Nguyen and Takahashi do not teach that the plasma effluents exhibit an etch selectivity between two or more of silicon germanium (SiGe), an oxide material, a nitride material, and a polysilicon materials, of greater than or about 1:1, as required by claims 2, 4, and 5.
Berry teaches plasma etching processes for semiconductor substrates in which etch selectivity between two or more of silicon germanium (SiGe), an oxide material, a nitride material, and a polysilicon materials of greater than or about 1:1 (paragraph [0027]).
It would have been obvious to one of ordinary skill in the art at the effective filing date of the claimed invention to modify the plasma etching process of Nguyen in view of Takahashi to achieve the selectivity relationships taught by Berry because controlling etch selectivity between different semiconductor materials is a known objective in plasma etching processes in order to selectively remove one material relative to another during semiconductor fabrication. See MPEP 2143(I)(C) which states that it is obvious to apply a known technique to improve a similar device.
Claim 3 is rejected under 35 U.S.C. 103 as being unpatentable over Nguyen in view of Takahashi and Berry as applied to claim 2 above, and further in view of Wang (US 2013/0045605 A1).
Nguyen, as modified by Berry above, teaches the limitations of claim 2.
However, Nguyen, as modified by Berry above does not teach that the etch selectivity is greater than or about 10:1 as required by claim 3.
Wang teaches plasma etching processes for semiconductor substrates in which silicon nitride is etched with a selectivity relative to silicon greater than or about 10:1 (paragraph [0019]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the plasma etching process of Nguyen, as modified by Berry, to achieve the higher selectivity values as taught by Wang because increasing etch selectivity is a known objective in plasma processes in order to improve pattern transfer and material removal control. See MPEP 2143(I)(C) which states that it is obvious to apply a known technique to improve a similar device.
Claim 7 is rejected under 35 U.S.C. 103 as being unpatentable over Nguyen in view of Takahashi, as applied to claim 1 above, and further in view of Tanaka et al (US 6361707 B1).
Nguyen teaches the limitations of claim 1 including a microwave applicator comprising a resonator body and a plate formed from dielectric material (paragraph [0051]).
Nguyen does not teach that the second dielectric material comprises quartz, alumina, sapphire, MgF2, yttrium aluminum garnet, Y2O3, MgO, calcium fluoride, barium fluoride, lithium fluoride, fused silica, borosilicate glass.
Tanaka teaches microwave plasma apparatus including a dielectric window formed from materials such as sapphire for transmitting microwave energy into a plasma processing chamber (col. 23, lines 28-36).
It would have been obvious to one of ordinary skill in the art at the time of the claimed invention to utilize the dielectric material taught by Tanaka in the microwave applicator, specifically the plate/window, of Nguyen because sapphire and similar dielectric materials are known to be transparent and plasma resistant materials commonly used in plasma processing chambers. The simple substitution of one known element for another is likely to be obvious when predictable results are achieved (MPEP § 2143(I)(B)).
Claim 8, 9, 10, 13, 14, and 17 is rejected under 35 U.S.C. 103 as being unpatentable over Nguyen in view of Takahashi, as applied to claim 1 above, and further in view Lubomirsky et al (US 2017/0229289 A1).
Regarding claims 8, 9, and 10, Nguyen teaches the limitations of claim 1 including generating a remote plasma in a remote plasma region.
Nguyen does not teach that the plasma precursors comprise a hydrogen-containing precursor and/or a halogen-containing precursor, including a hydrogen and fluorine-containing materials, or the claimed hydrogen ratios, as required by claims 8, 9, and 10.
Lubomirsky teaches plasma etching processes unitizing precursor gases including hydrogen-containing precursors and fluorine containing materials and further teaches hydrogen to fluorine ratios greater than or about 3:1 (paragraph [0109]).
It would have been obvious to one of ordinary skill in the art before the time of the effective filing date of the claimed invention to utilize the precursor compositions and ratios taught by Lubomirsky in the plasma etching system of Nguyen because precursor gas composition and ratios are recognized process variables in plasma etching systems that are routinely optimized to achieve desired etching performance. See MPEP 2143(I)(A), which explains that combining known elements according to yields predictable results is obvious.
Regarding claims 13, 14, and 17, Nguyen teaches the limitations of claim 1 including generating remote plasma in a remote plasma region.
Nguyen does not teach flowing hydrogen at a rate less than or about 1500 sccm, as required by claim 13, performing the etching at a pressure of about 1 torr to about 10 torr, as required by claim 14, or performing the etching at a temperature of about 20 C to about 125 C, as required by claim 17.
Lubomirsky teaches plasma processing conditions including hydrogen flow rates of less than or about 1500 sccm (paragraph [0109]), plasma processing pressure of about 1 torr to about 10 torr (paragraph [0113]), and processing temperature of about 20° C. to about 125° C (paragraph [0112]).
It would be obvious to one of ordinary skill in the art before the effective filing date of the invention to operate the plasma processing system of Nguyen using the hydrogen flow rate, pressure, and temperature conditions taught by Lubomirsky because such parameters are recognized process variables in plasma etching systems that are routinely adjusted to achieve desired processing results. It has been held that obviousness exists where the claimed ranges overlap or lie inside ranges disclosed by prior art. See MPEM 2144.05(I)
Claims 11, 12, and 15 are rejected under 35 U.S.C. 103 as being unpatentable over Nguyen in view of Takahashi, as applied to claim 1 above, and further in view Wang.
Regarding claims 11 and 12, Nguyen teaches the limitations of claim 1 including generating plasma in a semiconductor processing chamber.
Nguyen does not teach that the plasma source power is about 25 W to about 300 W or less than or about 50 W, as required by claims 11 and 12.
Wang teaches plasma etching processes in which plasma source power is about 25 W to about 300 W, including values less than or about 50 W (paragraph [0045]).
It would be obvious to one of ordinary skill in the art before the effective filing date of the invention to operate the plasma processing system of Nguyen with the plasma source power values within the range taught by Wang, including values that fall within the claimed ranges, because plasma power is a known operating parameter in plasma processing systems that is routinely adjusted to achieve desired plasma characteristics. It has been held that obviousness exists where the claimed ranges overlap or lie inside ranges disclosed by prior art. See MPEP 2144.05(I).
Regarding claim 15, Nguyen teaches the limitations of claim 1 including generating a remote plasma using precursor gases.
Nguyen does not teach introducing a nitrogen-containing precursor at a rate of about 25 sccm to about 150 sccm.
Wang teaches introducing nitrogen containing precursor gas into a processing region at a flow rate of about 25 sccm to about 150 sccm. (paragraph [0043]).
It would be obvious to one of ordinary skill in the art before the effective filing date of the invention to introduce the nitrogen-containing precursor taught by Wang into the plasma system of Nguyen because combining known process elements according to known methods yields predictable results. See MPEP 2143(I)(A). Furthermore, regarding the specific flow rate of the nitrogen-containing precursor, it has been held that obviousness exists where the claimed ranges overlap or lie inside ranges disclosed by prior art. See MPEP 2144.05(I).
Claim 16 is rejected under 35 U.S.C. 103 as being unpatentable over Nguyen in view of Takahashi, as applied to claim 1 above, and further in view Lill et al.(US 2016/0196984 A1).
Nguyen teaches that limitation of claim 1 including performing plasma etching within the semiconductor processing chamber.
Nguyen does not teach wherein the etch comprises an oxide bulk removal, a native oxide preclean, an oxide/nitride removal, a nitride recess, a silicon germanium recess, or a combination thereof, as required by instant claim 16.
Lill teaches a method of etching semiconductor substrate including oxide bulk removal and a native oxide preclean operations used to remove oxide layer from underlying semiconductor materials (paragraphs [0005], [0031]).
It would have been obvious to incorporate the oxide bulk removal and native oxide preclean operations taught by Lill into the plasma system of Nguyen because oxide bulk removal and preclean operations are conventional semiconductor fabrication steps preformed using plasma etching systems. See MPEP2143(I)(C), which states that it is obvious to apply a known technique to improve a similar device or process.
Claims 18 and 19 are rejected under 35 U.S.C. 103 as being unpatentable over Nguyen (US 2019/0326098 A1) in view of Tanaka et al (US 6361707 B1).
Regarding claim 18 and 19, Nguyen teaches a method of etching substrate in a semiconductor processing chamber 178 (paragraphs [0005][0031]. Nguyen further teaches flowing one or more plasma precursors through a microwave applicator 142 into a remote plasma region of a semiconductor processing chamber 178 (paragraphs [0031],[0051]). Nguyen further teaches generating a remote plasma within the remote plasma region at a microwave frequency, thereby forming plasma effluents from the plasma precursors (paragraphs [0029], [0051]). Nguyen also teaches flowing the plasma effluents into a processing region 589 of the semiconductor processing chamber 178 (paragraphs [0031],[0066]). Nguyen also teaches that the microwave applicator 142 comprises a resonator body/cavity 353/363 formed or coated with a first dielectric material including aluminum oxide and a dielectric window/plate 150 made up of a second dielectric material (paragraph [0051]).
However, Nguyen does not teach that the plate is formed or coated with a second dielectric materials comprising quartz, alumina, sapphire, MgF2, yttrium aluminum garnet, Y2O3, MgO, calcium fluoride, barium fluoride, lithium fluoride, fused silica, borosilicate glass.
Tanaka teaches microwave plasma apparatus including a dielectric windows formed from materials such as sapphire for transmitting microwave energy into a plasma processing chamber (col. 23, lines 28-36).
It would have been obvious to one of ordinary skill in the art before the effective date of the claimed invention to utilize sapphire as the dielectric plate material in Nguyen’s microwave applicator as taught by Tanaka because sapphire is a known microwave transparent, plasma resistant dielectric material suitable for plasma processing environments. The simple substitution of one known dielectric material for another in the microwave applicator is likely to be obvious when predictable results are achieved. See MPEP 2143 (I)(B).
Claim 20 is rejected under 35 U.S.C. 103 as being unpatentable over Nguyen in view of Berry, III et al.
Regarding claim 20, Nguyen teaches a method of etching substrate in a semiconductor processing chamber 178 (paragraphs [0005][0031]. Nguyen further teaches flowing one or more plasma precursors through a microwave applicator 142 into a remote plasma region of a semiconductor processing chamber 178 (paragraphs [0031],[0051]). Nguyen further teaches generating a remote plasma within the remote plasma region at a microwave frequency, thereby forming plasma effluents 196 from the plasma precursors (paragraphs [0029], [0051]) . Nguyen also teaches flowing the plasma effluents 196 into a processing region 589 of the semiconductor processing chamber 178 (paragraphs [0031],[0066]). Nguyen also teaches that the microwave applicator 142 comprises a resonator body/cavity 353/363 made of a first dielectric material including aluminum oxide and a dielectric window/plate 150 made up of a second dielectric material (paragraph [0051]).
Nguyen does not teach the plasma effluents exhibit an etch selectivity between the target material and a second material that includes silicon germanium (SiGe), an oxide material, a nitride material, and a polysilicon material, wherein the second material is different than the target material.
Berry teaches that plasma etching processes may exhibit selectivity between silicon germanium (SiGe), oxide materials, nitride materials, and polysilicon material (paragraph [0027]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to utilize the plasma etching process of Nguyen with the selectivity characteristics taught by Berry because controlling etch selectivity between semiconductor materials such as SiGe, oxide, nitride, and polysilicon is a known objective in plasma etching processes. See MPEP 2143(I)(C), which explains that it is obvious to apply a known technique to improve a similar device or process.
Conclusion
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/JONATHAN L CARTER/Examiner, Art Unit 1713
/JOSHUA L ALLEN/Supervisory Patent Examiner, Art Unit 1713