DETAILED ACTION
This is the Office action based on the 18782475 application filed July 24, 2024, and in response to applicant’s argument/remark filed on November 13, 2025. Claims 21-27, 29-33, 35-36 and 41-46 are currently pending and have been considered below. Applicant’s cancellation of claims 1-20, 28, 34 and 37-40 acknowledged.
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 .
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 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.
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 of this title, 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 set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied 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.
Claims 21-23 and 27 rejected under U.S.C. 103 as being unpatentable over Bukhman et al. (U.S. Pat. No. 5795493), hereinafter “Bukhman”, in view of Benjamin et al. (U.S. PGPub. No. 20050211385), hereinafter “Benjamin”, and Nikoh et al. (U.S. Pat. No. 5989929) , hereinafter “Nikoh”--Claims 21, 22, 23, 27 : Bukhman teaches a method of etching a semiconductor substrate (Claims 1-3; Fig. 2-4, 6), comprisingi) loading a substrate 40 having a layer to be etched onto a temperature-controlled chuck 52 (Col. 3, Lines 24-52; Fig. 1);ii) determining the initial thickness profile map by measuring thickness of the layer at a plurality of locations across the substrate (Fig. 6);iii) determine an initial heating profile map to produce a temperature profile at the plurality of locations according to the initial thickness profile map (Fig. 6; Col. 2, Line 66 through Col. 3, Line 24);iv) etch the layer while heating the substrate according to the heating profile map (Fig. 6; Col. 4, Line 30 through Col. 5, Line 67; Col. 6, Lines 48-59);v) measure the current thickness profile map, and determine and the next thickness profile map (Col. 5, Lines 39-46);vi) determine a next heating profile map based on a next thickness profile map during the etching (Fig. 6; Col. 5, Lines 45-46, Col. 6, Lines 48-51, Claim 10)vii) etch the layer while heating the substrate according to the next heating profile map (Fig. 6; Col. 4, Line 30 through Col. 5, Line 67; Col. 6, Lines 48-59);viii) repeating steps v) - vii) until the layer having a final thickness close to a predetermine final thickness (Fig. 6; Col. 6, Lines 31-36); Bukhman further teaches that the heating is performed by using an optical heating beam that scans the entire substrate to selectively heat the substrate according to the heating map (Col. 3, Lines 44-52), and the etching may be performed by supplying a plasma comprising a reactant, such as CF4 and oxygen, to the substrate (Col. 3, Lines 24-57). It is noted that the apparatus in Bukhman’s invention only heats the substrate, thus is not applicable when the etching requires a lower temperature. Bukhman fails to teach heating the substrate by using the temperature-controlled chuck 52. Benjamin, also directed to method of plasma etching a semiconductor substrate on a temperature-controlled chuck (Fig. 3, [0009, 0002-0004]), teaches that the chuck may be advantageously includes both a cooling loop and a heater, wherein the cooling loop provides cooling to the substrate ([0023]), wherein the heater comprises a plurality of heating elements, wherein each heating element defines a heating zone or region that may be controlled independently ([0026]), wherein at least one sensor 309 associated with each heating zone may measure the temperature of each heating zone and send a signal to a controller or computer system (see FIG. 7) to monitor and control each individual heating element to a desired temperature ([0027]). Therefore, it would have been obvious to one of ordinary skill in the art at the effective filing date of the invention to use the temperature-controlled chuck taught by Benjamin as the temperature-controlled chuck in the invention of Bukhman because Benjamin teaches that such temperature-controlled chuck can advantageously heat and/or cool the substrate to control the temperature at each of a plurality of locations across the substrate. It is noted that while the whole substrate, i.e. all regions, is cooled by the cooling loop, the heater only heats the regions that need to be heated. Bukhman further teaches that temperatures are measured, and heating and cooling are applied, based on portions of the substrate (Col. 3, Lines 10-23), and the heating is applied by using a laser that is scanned across the substrate, wherein the dwell time for each portion is controlled according to the heating profile map based on the assumption that increase in temperature is proportional to an increase in etch rate (Col. 4, Lines 9-50) Bukhman and Benjamin fail to teach the claim feature “a first site of the plurality of pre-etch surface heights has a first height and a second site of the plurality of pre-etch surface heights has a second height, the first height being greater than the second height” and “carrying out a first dry etch while the first zone is heated to the first target temperature and the second zone is concurrently cooled to the second target temperature; wherein the first dry etch reduces the first height of the first site to a third height and reduces the second height of the second site to a fourth height, wherein the third height is less than the fourth height”.
However, it is noted that etch rate non-uniformity and etch microloading effect are inherent in etching a semiconductor device. Nikoh teaches that microloading effect that occur in dense topography that may cause etch rate to vary depending on the aspect ratio of the feature and decrease when etching proceed to a certain depth (Fig. 37; Col. 1, Lines 26-42; Col. 2, Line 18-27). It would have been obvious to one of ordinary skill in the art at the effective filing date of the invention to perform the method of Bukhman on a substrate taught by Nikoh. Therefore, it would have been obvious to one of ordinary skill in the art at the effective filing date of the invention, in routine experimentations, that inherent etch non-uniformity and microloading effect may cause a first difference between an etch amount at a first portion inside a deep via hole and an etch amount at a second portion outside a deep via hole, to be much greater than a second difference between an etch amount at a first portion and an etch amount at a second portion when both are on a flat surface without any features, even when the same amount of heating is applied to both of them.. Thus, it would have been obvious to one of ordinary skill in the art at the effective filing date of the invention, in routine experimentations, to perform the method taught by Bukhman modified by Benjamin and Nikoh such that a the etching causes first site of the plurality of pre-etch surface heights has a first height and a second site of the plurality of pre-etch surface heights has a second height, the first height being greater than the second height such that the etching reduces the first height of the first site to a third height and reduces the second height of the second site to a fourth height, wherein the third height is less than the fourth height.--Claim 29: Bukhman further teaches that, by the selective etching different portions of the substrate, the method may produce a uniform semiconductor layer (Col. 6, Lines 26-66).
Claim 30 rejected under U.S.C. 103 as being unpatentable over Bukhman in view of Benjamin and Nikoh as applied to claims 21 above, and further in view of Li et al. (U.S. PGPub. No. 20220020665), hereinafter “Li”:--Claim 30: Bukhman modified by Benjamin and Nikoh teaches the invention as above. Bukhman further teaches that the method produce superior results than chemical mechanical polishing (Col. 6, Line 66 through Col. 7, Line 6). Bukhman , Benjamin and Nikoh fail to teach a substrate having the structures recited in claim 30.
Li teaches a method of chemical mechanical polishing, comprising bonding together a first substrate and second substrates, each comprises layers deposited in the FEOL, MOL, and frontside BEOL processes as well as the integrated interconnect structure, to form a stack then planarize the stack by chemical mechanical polishing ([0045]). Therefore, it would have been obvious to one of ordinary skill in the art at the effective filing date of the invention, in routine experimentations, to perform the method taught by Bukhman modified by Benjamin and Nikoh on the stack taught by Li because Li teaches to planarize the stack by chemical mechanical polishing and Bukhman teaches that the method produce superior results than chemical mechanical polishing.
Claims 24-25 rejected under U.S.C. 103 as being unpatentable over Bukhman in view of Benjamin and Nikoh as applied to claims 21 and 31 above, and further in view of Drab (U.S. PGPub. No. 20180114713), hereinafter “Drab”, and Cheng et al. (U.S. PGPub. No. 20170301611), hereinafter “Cheng”:--Claims 24, 25, 32, 33: Bukhman modified by Benjamin and Nikoh teaches the invention as above. Bukhman further teaches that the etching method may be used to remove a substrate that is a part of a stack comprising a handle wafer bonded to a device wafer (Claim 2), wherein a preliminary thinning step, such as grinding or chemical mechanical polishing, may be performed to reduce the substrate to a thickness to an initial thickness close to the desired final thickness before starting the etching method (Col. 6, Lines 1-47). Drab teaches a method of manufacturing an integrated circuit, comprising bonding a handle substrate 14 to an integrated circuit layer 12 that is formed over a substrate 13 (Fig. 3, [0024]), then removing the substrate 13 to expose the integrated circuit layer 12 (Fig. 4A), wherein the removal comprises first removing a substantial portion of the substrate 13, such as 90% of the substrate 13 (Fig. 5A), then finally removing the remaining of the substrate, wherein the removing may be performed by etching, grinding and polishing ([0025]) Therefore, it would have been obvious to one of ordinary skill in the art at the effective filing date of the invention, in routine experimentations, to use the etching method taught by Bukhman to remove the remaining of the substrate 13 in the invention of Drab because Bukhman teaches that the etching method may be used to remove a substrate that is a part of a stack comprising a handle wafer bonded to a device wafer. Drab further teaches that the remaining of the substrate after the first removal may be 10u or less ([0025]). Therefore, it would have been obvious to one of ordinary skill in the art at the effective filing date of the invention, in routine experimentations, to remove at least 95% of the substrate to a thickness of 10u or less during the first removal by using polishing in the invention of Bukhman modified by Drab. Bukhman and Drab are silent about the details of the polishing process or a total thickness variation of the initial thickness after the polishing before the etching method. Cheng teaches a method for polishing a silicon substrate for thinning the silicon substrate, the method produces a substrate having a total thickness variation less than 0.5 micrometer ([0025]). Therefore, it would have been obvious to one of ordinary skill in the art at the effective filing date of the invention, in routine experimentations, to use the polishing method taught by Cheng for the preliminary thinning step in the invention of Bukhman because Bukhman teaches to perform such polishing but is silent about the details, and Cheng teaches that such polishing method would be effective.
Allowable Subject Matter
Claims 31-33, 35-36 and 41-46 are allowable. The following is a statement of reasons for the indication of allowable subject matter: With respect to claim 31, none of the cited prior arts teaches the feature “positioning a nozzle over a first site of the plurality of sites based on a surface height of the first site, and dispensing a liquid etchant through the nozzle to etch the first site while some of the plurality of sites are free from the liquid etchant” in the context of claim 26;With respect to claim 31, none of the cited prior arts teaches the feature “positioning a nozzle over a site of the plurality of sites based on a surface height of the site, and dispensing a liquid etchant through the nozzle to etch the site while some of the plurality of sites are free from the liquid etchant, and the semiconductor wafer is stationary with respect to the work piece support” in the context of claim 31;With respect to claim 41, none of the cited prior arts teaches the feature “positioning a nozzle over a site of the plurality of sites based on a surface height of the site, and dispensing a liquid etchant through the nozzle to etch the site while some of the plurality of sites are free from the liquid etchant, and the work piece is stationary with respect to the wafer chuck” in the context of claim 41.
Claim 26 objected to as being dependent upon a rejected base claim, but would be allowable if rewritten to include 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: With respect to claim 26, none of the cited prior arts teaches the feature “positioning a nozzle over a site of the plurality of sites based on a surface height of the site, and dispensing a liquid etchant through the nozzle to etch the first site while some of the plurality of sites are free from the liquid etchant” in the context of claim 26.
Any comments considered necessary by applicant must be submitted no later than the payment of the issue fee and, to avoid processing delays, should preferably accompany the issue fee. Such submission should be clearly labeled “Comments on Statement of Reasons for Allowance”.
Response to Arguments
Applicant's arguments filed February 2, 2023 have been fully considered as follows:--Regarding Applicant’s argument that the cited prior arts do not teach the amended feature in claims 31 and 41, this arguments is persuasive. Claims 31-33, 35-36 and 41-46 are allowable.--Regarding Applicant’s argument that the cited prior arts do not teach the amended feature in claims 21, this arguments is persuasive in view of newly found prior arts, as explained above.--Claim 26 recites an allowable subject matter, as stated in the previous Office action.
Conclusion
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any extension fee pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to THOMAS PHAM whose telephone number is (571) 270-7670 and fax number is (571) 270-8670. The examiner can normally be reached on MTWThF9to6 PST.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Joshua Allen can be reached on (571) 270-3176. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/THOMAS T PHAM/Primary Examiner, Art Unit 1713