DETAILED ACTION
Claims 1-21 are pending before the Office for review.
In the response filed December 31, 2025:
Claim 1 was amended.
No new matter was present.
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 .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on December 31, 2025 has been entered.
Priority
Receipt is acknowledged of certified copies of papers required by 37 CFR 1.55.
Election/Restrictions
Claims 17-20 are withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected invention, there being no allowable generic or linking claim. Election was made without traverse in the reply filed on March 25, 2025.
Applicant’s election without traverse of Group I (claims 1-16) in the reply filed on March 25, 2025 is acknowledged.
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 1-6, 8, 10-11 and 14-16 are rejected under 35 U.S.C. 103 as being unpatentable over MENG et al (CN110137080 as evidenced by the machine translation) in view of HIRAYAMA et al (U.S. Patent Application Publication 2014/0134846).
With regards to claim 1, Meng discloses a method for etching a silicon wafer (Page 4 discloses providing a substrate 21 which may be a single substrate composed of a material such as single crystal silicon), comprising: a main etching process ( cycle step a) using a first mixed gas to perform a plasma etching process to etch the silicon wafer until a pattern on the silicon wafer reaches a specified aspect ratio, the first mixed gas being configured to etch silicon and react with silicon to form non-volatile reaction products (Pages 4-6 discloses performing a first etching process to etch a portion of a silicon wafer to a predetermined depth wherein the first etching generates solid by products) ; and an auxiliary etching process using a second mixed gas to perform another plasma etching process, the second mixed gas being configured to react with silicon to generate the non-volatile reaction products (Pages 4-6 discloses performing step b etching the bottom of the first sub-etched structure with a second etching gas to form a second sub-etched structure wherein a solid byproduct is generated), wherein the main etching process and the auxiliary etching process are alternately performed at least once until the pattern on the silicon wafer (Paragraphs 2-6 discloses performing the etching cycle of first etching a followed by second etching b; wherein the cycle is repeated until the desired etching depth is reached).
Meng does not explicitly disclose a formation rate of the non-volatile reaction products in the auxiliary etching process being greater than a formation rate of the non-volatile reaction products in the main etching process; and wherein the main etching process and the auxiliary etching process are alternately performed at least once until the pattern on the silicon wafer reaches a specified etching depth.
However Meng discloses wherein the substrate is etched with a first etching gas and a second etching gas wherein the first etching gas produces less solid byproduct than second etching gas (See Page 2). Hirayama discloses a plasma processing method rendering obvious a formation rate of the non-volatile reaction products in the auxiliary etching process being greater than a formation rate of the non-volatile reaction products in the main etching process wherein a first etching process etches to an initial depth H1 and a second etching process etches to H2 and the etching processes are repeated until the final depth H is achieved (Paragraphs [0055], [0059], [0072]-[0073], [0082]-[0083], [0095]).
It would have been prima facie obvious to one of ordinary skill in the art prior to the effective filing date of the invention to modify the method of Meng to include the formation rate of the non-volatile reaction products as rendered obvious by the embodiment of Meng because the reference of Meng teaches that such reaction product coating provides an improvement in morphology of the etching structure with avoidance of occurrence of insufficient etching at the bottom of the etched structure and avoiding lateral over etching (Pages 1-2, 5) and one of ordinary skill in the art prior to the effective filing date of the would have had a reasonable expectation of predicably achieving the desired etching using the formation rate of the non-volatile reaction product as rendered obvious by Meng. MPEP 2143D
It would have been prima facie obvious to one of ordinary skill in the art prior to the effective filing date of the invention to modify the method of Meng to alternating etching until a specified etching is reached as rendered obvious by the embodiment of Hirayama because one of ordinary skill in the art prior to the effective filing date of the would have had a reasonable expectation of predicably achieving the desired etching using the etching to a specified etching depth as rendered obvious by Hirayama. MPEP 2143D
With regards to claim 2, the modified teachings of Meng renders obvious wherein: the specified etching depth is smaller than a target etching depth; and after the main etching process and the auxiliary etching process are alternately performed, the main etching process is performed at least once until the pattern on the silicon wafer reaches the specified etching depth (Meng Pages 1, 4-5 discloses providing a first sub etched structure and a second sub etch structure where the second sub etched structure is sued as a substrate for the next cycle etching wherein the cycle etching is performed until the high aspect ratio is reached Hirayama Paragraphs [0055], [0059], [0072]-[0073], [0082]-[0083], [0095] discloses etching with the second etching step etches a second depth H2; cycle etching to reach final depth H).
With regards to claim 3, the modified teachings of Meng discloses wherein forming a first depth H1 with the first etch process, a second depth H2 and a third depth H3 until the desired aspect ratio is formed (Meng Pages 3-6, Hirayama Paragraphs [0072]-[0073], [0082]-[0083], [0095]). Generally, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. "[W]here 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) MPEP 2144.05(II)(A) It would have been prima facie obvious to one of ordinary skill in the art prior to the effective filing date of the invention to optimize the specified aspect ratio achieved after the main etching process to amounts including Applicant’s claimed amount of greater than or equal to N-1:1 and less than or equal to N:1, wherein N is a sequence number of the main etching processes in order to achieve the desired aspect ratio etching while protecting the sidewall from lateral etching and providing good morphology and etching depth that ensures the yield of the semiconductor device (Meng Pages 4-5 Hirayama Paragraphs [0072]-[[07], [0082]-[0083], [0088], [0095]), MPEP 2144.05(II)(A)).
With regards to claim 4, the modified teachings of the modified teachings of Meng discloses wherein forming a first depth H1 with the first etch process, a second depth H2 and a third depth H3 until the desired aspect ratio is formed wherein the etching depth ensures the yield of the semiconductor device (Meng Pages 3-6, Hirayama Paragraphs [0072]-[0073], [0082]-[0083], [0095]). Generally, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. "[W]here 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) MPEP 2144.05(II)(A) It would have been prima facie obvious to one of ordinary skill in the art prior to the effective filing date of the invention to optimize the specified aspect ratio to amounts including Applicant’s claimed amount of greater than or equal to 3:1 and less than or equal to 5:1 in order to etch the high aspect etching device with an etching depth that ensure the yield of the semiconductor device as taught by the modified teachings of Meng. (Meg Pages 3-6, MPEP 2144.05(II)(A)).
With regards to claim 5, the modified teachings of Meng discloses wherein the second etching process the second etching gas formed a second sub-etched structure wherein the etching rate of step b is relatively slow, wherein the byproducts is controlled to prevent the occurrence of insufficient etching at the bottom of the structure (Meng page 5) where in relative etch time is adjusted to control the amount of solid by products formed and amount of etching to ensure smooth process of the etching process (Men Page 6). Generally, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. "[W]here 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) MPEP 2144.05(II)(A) It would have been prima facie obvious to one of ordinary skill in the art prior to the effective filing date of the invention to optimize the a duration of the auxiliary process to amounts including Applicant’s claimed amount of greater than or equal to 2 seconds and smaller than or equal to 3 seconds in order to control the byproducts and prevent the occurrence of insufficient etching at the bottom of the structure (Meng page 5) such that the duration of etching ensures a smooth process of the etching (Men Page 6, MPEP 2144.05(II)(A)).
With regards to claim 6, the modified teachings of Meng renders obvious wherein: the first mixed gas includes sulfur hexafluoride, and one or more of oxygen, hydrogen bromide and silicon tetrafluoride (Hirayama Paragraph [0072]); and the second mixed gas includes one or more of oxygen, hydrogen bromide and silicon tetrafluoride (Hirayama Paragraph [0082]).
With regards to claim 8, the modified teachings of Meng renders obvious wherein: the second mixed gas further includes sulfur hexafluoride. (Hirayama Paragraph [0082]).
With regards to claim 10, the modified teaching of Meng discloses wherein during etching the silicon substrate the can be performed wherein the main etching process (first etching process) wherein the first high frequency is 2200W which renders obvious when performing the main etching process, a value range of an upper radio frequency (RF) power is greater than or equal to 300W and less than or equal to 2,500W; and when performing the auxiliary etching process (second etching process) the first high frequency is 1800W which renders obvious a value range of an upper RF power is greater than or equal to 500W and less than or equal to 2,000W, a second high frequency power is 200 which renders obvious a value range of the lower RF power is greater than or equal to 50W and less than or equal to 500W, and the pressure in the process chamber is 40mTorr which renders obvious and the pressure in the process chamber ranges between 10 mT and 100 mT. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976). MPEP 2144.05(I) In addition, the modified teachings of Meng discloses adjusting and incrementally increasing the first high frequency and second high frequency powers and process chamber pressure between processing steps in order to etch the desired shape of hole while preventing irregularities (Hirayama [0093]-[0096]). Generally, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. "[W]here 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) MPEP 2144.05(II)(A) It would have been prima facie obvious to one of ordinary skill in the art prior to the effective filing date of the invention to optimize the processing conditions to include wherein during the main etching process a value range of the lower RF power is amounts including Applicant’s claimed amount of greater than or equal to 15W and less than or equal to 800W, and a pressure in a process chamber is amounts including Applicant’s claimed amounts of between 10 mT and 90 mT because the modified teachings of Meng discloses adjusting and incrementally increasing the first high frequency and second high frequency powers and process chamber pressure between processing steps in order to etch the desired shape of hole while preventing irregularities (Hirayama [0093]-[0096], MPEP 2144.05(II)(A)).
With regards to claim 11, the modified teachings of Meng renders obvious further comprising before the main etching process is performed for the first time: a pre-etching process using a pre-etching gas to perform the plasma etching process to etch the silicon wafer and remove an oxide layer on the surface of the silicon wafer (Hirayama Paragraphs [0055]-[0058]).
With regards to claims 14-15, the modified teaching of Meng discloses wherein the temperature of the susceptor and chamber is set to an amount in order to arrange the sidewall of a hole being formed though etching to be substantially vertical (Hirayama Paragraph [0042]). Generally, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. "[W]here 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) MPEP 2144.05(II)(A) It would have been prima facie obvious to one of ordinary skill in the art prior to the effective filing date of the invention to optimize the temperature to amounts including Applicant’s claimed amounts of when performing the main etching process, a temperature range of a base in the process chamber is less than or equal to 100 °C, and a temperature range of the process chamber is greater than or equal to 10 °C and less than or equal to 40 °C; and when performing the auxiliary etching process, the temperature range of the process chamber is greater than or equal to 10 °C and less than or equal to 40 °Cn wherein: when performing the main etching process, the temperature range of the base in the process chamber is greater than or equal to 20 °C and less than or equal to 80 °C. in order to set an amount in order to arrange the sidewall of a hole being formed though etching to be substantially vertical as taught by the modified teachings of Meng (Hirayama Paragraph [0042]).
With regards to claim 16, the modified teachings of Meng renders obvious wherein: the pre-etching gas includes one or more combinations of carbon tetrafluoride or other fluorine-containing hydrocarbon organic gases (Meng Page 6 discloses initial etching with a fluorocarbon including CF4).
Claim 13 is rejected under 35 U.S.C. 103 as being unpatentable over MENG et al (CN110137080 as evidenced by the machine translation) in view of HIRAYAMA et al (U.S. Patent Application Publication 2014/0134846), as applied to claims 1-6, 8, 10-11 and 14-16, in further view of EIJI et al (JP H11135489 as evidenced by the machine translation).
With regards to claim 13, the modified teaching of Meng renders obvious the limitations of claim 1 as previously discussed.
The modified teachings of Meng are silent as to wherein: frequencies of the upper and lower RF powers are 13.56MHz in both the main etching process and the auxiliary etching process.
Eiji discloses a method for etching a high aspect ratio in a silicon wafer comprising oxygen, hydrogen bromide, silicon tetrafluoride, and sulfur tetrafluoride using a power frequency of 13.56 MHz (Paragraph [0022]) which renders obvious wherein: frequencies of the upper and lower RF powers are 13.56MHz in both the main etching process and the auxiliary etching process.
It would have been prima facie obvious to one of ordinary skill in the art prior to the effective filing date of the invention to further modify the modified method of Meng to include RF powers as rendered obvious by Eiji because one of ordinary skill in the art prior to the effective filing date of the would have had a reasonable expectation of predicably achieving the desired etching using the RF powers as rendered obvious by the teachings of Eiji. MPEP 2143D
Allowable Subject Matter
Claim 21 is allowed.
Claims 7, 9 and 12 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 closest prior art to newly add claim 21 is Meng in view of Hiraua,, Teshima and Eiji. However Applicant’s newly added claim 21 includes the limitations of “… wherein: in different main etching processes, the specified aspect ratio is different; the first mixed gas includes at least one gas being able to react with silicon to form non-volatile reaction products, and a formation rate of the non-volatile reaction products in the auxiliary etching process being greater than a formation rate of the non- volatile reaction products in the main etching process; the second mixed gas includes one or more of oxygen, hydrogen bromide, silicon tetrafluoride, and silicon tetrachloride; the first mixed gas includes sulfur hexafluoride, oxygen, hydrogen bromide, and silicon tetrafluoride, and a flow ratio of sulfur hexafluoride, oxygen, hydrogen bromide, and silicon tetrafluoride is (1.7-2.3) : (1.3-1.7) : (13-17) : 1; and the first mixed gas and the second mixed gas satisfy at least one of: a flow rate of the oxygen in the first mixed gas is smaller than a flow rate of the oxygen in the second mixed gas; a flow rate of the hydrogen bromide in the first mixed gas is smaller than a flow rate of the hydrogen bromide in the second mixed gas; or a flow rate of the silicon tetrafluoride in the first mixed gas is smaller than a flow rate of the silicon tetrafluoride in the second mixed gas.” As required by claim 21. A further search of the prior art has failed to produce analogous art which teaches or renders obvious Applicant’s claimed invention.
Response to Arguments
Applicant’s arguments, see pages 10-11, filed December 31, 2025, with respect to 112 rejection of claims 1-16 have been fully considered and are persuasive. The 112b rejection of claims 1-16 has been withdrawn.
Conclusion
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/STEPHANIE P DUCLAIR/Primary Examiner, Art Unit 1713