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 .
Information Disclosure Statement
The information disclosure statement (IDS) submitted on 06/20/2023 and 08/01/2024 are in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statement is being considered by the examiner.
Election/Restrictions
Applicant’s election of species 1 corresponding to claims 1-10 and 27-36 with traverse in the reply filed on 02/25/2026 is acknowledged. Because applicant did not distinctly and specifically point out the supposed errors in the restriction requirement, the election has been treated as an election without traverse (MPEP 818.01 (a))
Therefore, the Examiner will examine claims 1-10 and 27-36.
The requirement is still deemed proper and is therefore made FINAL
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.
Claims 31-36 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.
Regarding Claim 31,
Claim 31 recites the limitation, “wherein concentrations of fluorine in etchants of the plurality of etching processes decrease and then increase during the performing of the plurality of etching processes.”. The Examiner finds this limitation to be indefinite as it is not clear what the starting concentration of fluorine is. In the case where the starting concentration of fluorine is 0, it is not possible for the concentration of fluorine to first decrease. Applicant’s elected species indicates that the first etchant uses fluorine. Therefore it is not possible for a concentration of fluorine to first decrease because the inclusion of fluorine as a first etchant necessarily means that the concentration of fluorine first increases from nothing. The Examiner interprets the limitation above as meaning, “wherein the plurality of etching processes comprises performing a first etching process and a third etching process, wherein the first etching process comprises a first concentration of fluorine which decreases, wherein the third etching process comprises a second concentration of fluorine which increases.” The Examiner notes that were the Applicant to implement the amended limitation above, then the limitations of claim 34 would also need to be adjusted.
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 31 and 33 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Shen et al US 20210249350 A1. Shen et al will be referenced to as Shen henceforth.
Regarding Claim 31,
Shen teaches:
“A method, comprising:
providing a structure comprising:
a first dielectric layer (first dielectric layer 250, [0024], FIG. 19),
a lower contact feature in the first dielectric layer (lower contact feature, 253, FIG. 19),
a second dielectric layer over the lower contact feature and the first dielectric layer (second dielectric layer 256, [0027], FIG. 19),
a metal-insulator-metal (MIM) structure over the second dielectric layer (MIM structure 260, [0032], FIG. 19), wherein the MIM structure comprises a first conductor plate layer (bottom conductor plate 262, [0037] FIG. 19), a second conductor plate layer over the first conductor plate layer (top conductor plate layer 269, [0037] FIG. 19), and an insulator layer between the first and the second conductor plate layers (second insulator layer 268, [0029] FIG. 19: MIM stands for metal insulator metal.), and
a third dielectric layer over the MIM structure (fourth dielectric layer 267, [0032], FIG. 19);
performing a plurality of etching processes to form an opening through the third dielectric layer, the MIM structure, and the second dielectric layer (opening 271, [0033-0034], FIGs. 15-17), thereby exposing the lower contact feature (FIG. 17); and
forming an upper contact feature in the opening (upper contact feature 275, [0038], FIGs. 17-18),
wherein concentrations of chlorine in etchants of the plurality of etching processes increase and then decrease during the performing of the plurality of etching processes ([0033-0035], FIGs. 15-17: The first etch process contains fluorine and no chlorine. The second etch process contains chlorine and no fluorine. The third etch process contains fluorine and no chlorine.),wherein concentrations of fluorine in etchants of the plurality of etching processes decrease and then increase during the performing of the plurality of etching processes ([0033-0035], FIG. 15-17: The first etch process contains fluorine and no chlorine. The second etch process contains chlorine and no fluorine. The third etch process contains fluorine and no chlorine.).”
Regarding Claim 33,
Shen teaches:
“The method of claim 31, wherein the lower contact feature is a first lower contact feature ([0026], FIG. 17: 253 is the first lower contact feature from the left side of the device.), the opening is a first opening (([0033], FIG. 17: 271 is the first opening from the left side of the device.), and the upper contact feature is a first upper contact feature (0026], FIG. 17: 253 is the first lower contact feature from the left side of the device.), the opening is a first opening (([0033], FIG. 17: 271 is the first opening from the left side of the device.), wherein the structure further comprises a second lower contact feature in the first dielectric layer (lower contact feature 254, [0026], FIG. 17: 254 is the second lower contact feature from the left.), wherein performing the plurality of etching processes further forms a second opening through the third dielectric layer, the MIM structure, and the second dielectric layer, thereby exposing the second lower contact feature (opening 272, [0033], FIG. 17), wherein the second opening is wider than the first opening ([0042], FIG. 17, FIG. 22A-22B: 271 may have a width of 3200 nm. 272 may have a diameter of 3800 nm.).”
Allowable Subject Matter
Claims 1-10 and 27-30 are allowed. The following is the Examiner’s reasoning for allowance.
The best prior arts the Examiner found include Shen, Bhat et al US 6037246 A, Huang et al US 20200035779 A1, and Coolbaugh et al US 20070190718 A1. Bhat et al, Huang et al, and Coolbaugh et al will be referenced to as Bhat, Huang, and Coolbaugh respectively.
Regarding Claim 1,
Shen/Bhat/Huang/Coolbaugh fails to explicitly teach :
“performing a fourth etch process to further extend the opening through the third dielectric layer and the second dielectric layer to expose the lower contact feature”, “the fourth etch processes comprise a third etchant, wherein the first etchant and the third etchant comprise fluorine”, and “wherein performing the fourth etch process comprises applying a non-zero bias power and a non-zero source power to the workpiece.” In view of the rest of the limitations of claim 1.
Shen/Bhat/Huang/Coolbaugh fails to explicitly teach the above limitation because the limitations cannot be found in the prior art of record or a combination is not obvious.
This is because Shen does not teach a fourth etching process using fluorine with a non-zero source power and a non-zero bias power. Rather, Shen teaches three etching processes, wherein the third etching process extends through a third dielectric layer and a second dielectric feature to expose a lower contact feature. None of Bhat, Huang, or Coolbaugh teach the above limitations. The closest reference, Coolbaugh, teaches four etching processes wherein the fourth etching process etches a third conductive layer and a second conductive layer (the second conductive layer is made of SiN) with fluorine using RIE etching. RIE etching has a non-zero source and bias. However, one of ordinary skill in the art would not find it obvious to combine Shen and Coolbaugh because of the significantly different geometry of Coolbaugh. Namely that no etchant is used to etch through the MIM of Coolbaugh to reach a lower electrode.
The Examiner did not find prior art which one of ordinary skill in the art would use alone or would find obvious to combine with the invention of Shen/Bhat/Huang/Coolbaugh to reach all of the limitations of the claim.
Regarding Claims 2-10, these claims depend on claim 1 and are allowable for the same reasons.
Regarding Claim 27,
Shen/Bhat/Huang/Coolbaugh fails to explicitly teach :
“wherein the cleaning process recesses the two conductor plate layers at a first rate and recesses the insulator layer at a second rate smaller than the first rate.” In view of the rest of the limitations of claim 27.
Shen/Bhat/Huang/Coolbaugh fails to explicitly teach the above limitation because the limitation cannot be found in the prior art of record or a combination is not obvious.
This is because Shen teaches the use of a cleaning process after the use of a third etching process but does not teach that the cleaning process would recess the two conductor plates at a rate faster than a recess rate of an insulating layer. None of Bhat, Huang, or Coolbaugh teach the above limitations. The references closest to teaching this limitation are Bhat and Huang. Bhat teaches a cleaning process using hydrogen peroxide to recess two conductive metal silicide layers at a rate faster than a rate of insulating layers. However, one of ordinary skill in the art would not have found it obvious to combine Bhat with Shen because the conductive layers of Shen are made of a pure metal or a metal nitride and not a metal silicide. Huang also teaches a slower etch rate for an insulating layer relative to the etch rate of conducting plates. However, this etching is not done during a cleaning process.
The Examiner did not find prior art which one of ordinary skill in the art would use alone or would find obvious to combine with the invention of Shen/Bhat/Huang/Coolbaugh to reach all of the limitations of the claim.
Regarding Claims 28-30, these claims depend on claim 27 and are allowable for the same reasons.
Claims 32 and 34-36 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.
Regarding Claim 32,
Shen/Bhat/Huang/Coolbaugh fails to explicitly teach :
“further comprising performing a cleaning process, wherein the cleaning process recesses the first and the second conductor plate layers at a first rate and recesses the insulator layer at a second rate smaller than the first rate” In view of the rest of the limitations of claim 31.
Shen/Bhat/Huang/Coolbaugh fails to explicitly teach the above limitation because the limitation cannot be found in the prior art of record or a combination is not obvious.
This is because Shen teaches the use of a cleaning process after the use of a third etching process but does not teach that the cleaning process would recess the two conductor plates at a rate faster than a recess rate of an insulating layer. None of Bhat, Huang, or Coolbaugh teach the above limitations. The references closest to teaching this limitation are Bhat and Huang. Bhat teaches a cleaning process using hydrogen peroxide to recess two conductive metal silicide layers at a rate faster than a rate of insulating layers. However, one of ordinary skill in the art would not have found it obvious to combine Bhat with Shen because the conductive layers of Shen are made of a pure metal or a metal nitride and not a metal silicide. Huang also teaches a slower etch rate for an insulating layer relative to the etch rate of conducting plates. However, this etching is not done during a cleaning process.
The Examiner did not find prior art which one of ordinary skill in the art would use alone or would find obvious to combine with the invention of Shen/Bhat/Huang/Coolbaugh to reach all of the limitations of the claim.
Regarding Claim 34,
Shen/Bhat/Huang/Coolbaugh fails to explicitly teach :
“performing a fourth etching process to extend the initial opening in a bottom portion of the second dielectric layer, thereby forming the opening” In view of the rest of the limitations of claim 34.
Shen/Bhat/Huang/Coolbaugh fails to explicitly teach the above limitation because the limitations cannot be found in the prior art of record or a combination is not obvious.
This is because Shen does not teach a fourth etching process. Rather, Shen teaches three etching processes, wherein the third etch process extends through a third dielectric layer and a second dielectric feature to expose a lower contact feature. None of Bhat, Huang, or Coolbaugh teach the above limitations. The closest reference, Coolbaugh, teaches four etching processes wherein the fourth etching process etches a third conductive layer and a second conductive layer (the second conductive layer is made of SiN) with fluorine using RIE etching. However, one of ordinary skill in the art would not find it obvious to combine Shen and Coolbaugh because of the significantly different geometry of Coolbaugh. Namely that no etchant is used to etch through the MIM of Coolbaugh to reach a lower electrode.
The Examiner did not find prior art which one of ordinary skill in the art would use alone or would find obvious to combine with the invention of Shen/Bhat/Huang/Coolbaugh to reach all of the limitations of the claim.
Regarding Claims 35-36, these claims depend on claim 34 and are objected to for the same reasons.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to ALEXANDRE XAVIER RAMIREZ whose telephone number is (571)272-2715. The examiner can normally be reached Monday - Friday 8:30 AM to 6:00 PM.
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/ALEXANDRE X RAMIREZ/Examiner, Art Unit 2812
/William B Partridge/Supervisory Patent Examiner, Art Unit 2812
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