DETAILED ACTION
This is the Office action based on the 18573700 application filed December 22, 2023, and in response to applicant’s argument/remark filed on April 29, 2026. Claims 1-20 are currently pending and have been considered below.
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.
Election/Restrictions
Applicant’s election, without traverse, of the invention of Group I, claims 1-8 in the reply filed on April 29, 2026 is acknowledged. Claims 9-20 withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected invention.
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 1-8 rejected under 35 U.S.C. 103 as being unpatentable over Arai et al. (U.S. PGPub. No. 20090194234), hereinafter “Arai”:--Claims 1, 4: Arai teaches a method of etching, comprising:
providing a semiconductor wafer ([0002]):thinning the wafer by wet etching ([0008], Fig. 6A and 9), the etching comprises - rotating the wafer at a low speed, such as 50 rpm (Claim 2); - supplying etching liquid to the wafer by using a nozzle, wherein the etching liquid comprises nitric acid and HF ([0047, 0051]), wherein the etching liquid is supplied at a constant rate, such as 0.85 slm or 1.5 L/min ([0105]) ([0073]), wherein the nozzle is scanned in a radial direction across the wafer ([0072, 0105]) at a speed 160 mm/sec ([0082]) between to position T1 adjacent to the rotation center of the wafer to a position T2 outside the wafer ([0072]). Arai further teach that there is an annular surface surrounds the wafer and causes the etching liquid to be retained on the wafer ([0095-0096], Fig. 6B), and that the wafer may be rotated at 5 rpm ([0104, 0106]) that would hardly generate a centrifugal force to act on the etching liquid ([0106, 0110]), and still exhibits high etching rate and improved uniformity ([0110]). Therefore, it would have been obvious to one of skill in the art to produce desirable etch rate and etch rate uniformity by setting the process parameters such that the second duration, which is the time it takes for an etching liquid moves from the center of the wafer to the edge of the wafer. is greater than the first duration that the nozzle passes the wafer center, travels to the end of the scan, then turning around and reaches the wafer center again because it’s been well established that "[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).--Claims 2, 3, 5: Arai further discloses that the scanning of the nozzle may be at a first position outside the wafer proximate to the edge of the wafer, and reciprocate at a second position proximate the center of the wafer ([0071-0073]).In an embodiment Arai teaches that the second position may be about 22.5 mm from the center of the wafer ([0072]). Therefore, it would have been obvious to one of skill in the art to select a second position at a distance less than half or less than one third of the radius from the center of the wafer in routine experimentations in the invention of Arai. It is noted that the wafer may have a radius 50 mm, 75 mm, 100 mm, etc.--Claims 6, 7: Arai further teach to determine etch rate uniformity across the wafer ([0087]). Therefore, it would have been obvious that a thickness of the wafer is measured across the wafer prior to the etching, and after the etching in the invention of Arai.--Claim 8: Since Arain teaches that the wafer may be rotated at 5 rpm ([0104, 0106]) that would hardly generate a centrifugal force to act on the etching liquid ([0106, 0110]), and still exhibits high etching rate and improved uniformity ([0110] it would also have been obvious for one of skill in the art to determine a relationship between the etch rate and the rotation speed prior to performing an etch operation in the invention of Arai.
Claims 1-4 and 6-8 rejected under 35 U.S.C. 103 as being unpatentable over Yoshikawa et al. (JP2010177541A, see attachments), hereinafter “Yoshikawa”:--Claims 1, 4: Yoshikawa teaches a method of etching, comprising:
Providing a silicon wafer:thinning the wafer by using a grinding wheel (Ref#1, Claim 1);wet etching the wafer to remove the damage caused by the thinning (Ref #2), the etching comprises - rotating the wafer at speed 50-700 rpm (Claim 2); - supplying etching liquid to the wafer by using a nozzle (Claim 8), wherein the nozzle is scanned in a radial direction across the wafer (Claim 11), wherein the etching liquid comprises nitric acid at 31.5-54.09 wt.%, HF at 4.45-24.5 wt.%, and 5-13.64 wt.% acetic acid (Claim 1), wherein the etching liquid is supplied at 0.3-1.5 slm at 30-85°C (Claim 2), and wherein the scan speed is 40 deg./sec and scan width is -16 to 80 mm (Ref #3). In an embodiment Yoshikawa discloses that the scan speed is 50 deg./sec and scan width is -80 to 80 mm (Ref #4) or -100 to +100 mm (Ref #5), and that the process parameters, e.g. concentration and temperature of the acids, scan speed, scan width, rotation speed, etc. may be optimized to produce desirable etch rate and etch rate uniformity (Examples 1-10). Since the concentration and temperature of the acids affect the viscosity of the etching liquid, and the second duration that the etching liquid that is applied to the center of the wafer to spread to the edge of the wafer due to the centrifugal force is affected by the viscosity of the etching liquid and the rotation speed, it would have been obvious to one of skill in the art to produce desirable etch rate and etch rate uniformity by setting the process parameters such that the second duration is greater than the first duration that the nozzle passes the wafer center, travels to the end of the scan, then turning around and reaches the wafer center again because it’s been well established that "[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 is noted that the scan speed and scan width disclosed by Yoshikawa may enable the second duration to be short, while the high concentrations of the acid, the low process temperature, and the low rotation speed may result in a greater first duration. --Claims 2, 3: It is noted that in the scan width -16 to 80 mm, the scan width on the left side of the wafer is 16 mm, which is 16% the radius of the wafer, which is 100 mm (Ref #5). Yoshikawa further teaches that the wafer may have a radius of 150 mm (Fig. 4A).--Claims 6, 7: Fig. 4A shows the relationship between the measurement position and the etching rate. Therefore, it is obvious that a thickness of the wafer is measured across the wafer prior to the etching, and after the etching in the invention of Yoshikawa.--Claim 8: Yoshikawa further teaches that a relationship between the etch rate and the scan width(Ref #3 and $4) and/or the rotation speed (Fig. 4, Ref# 6) is determined. Therefore, it is obvious for one of skill in the art to determine a relationship between the etch rate and the scan width and/or the rotation speed prior to performing an etch operation in the invention of Yoshikawa
Claim 5 rejected under 35 U.S.C. 103 as being unpatentable over Yoshikawa as applied to claim 1 above, and further in view of Arai:--Claim 5: Yoshikawa teaches the invention as above. Yoshikawa is silent about a position of the nozzle at the end of an etching operation.Arai, also directed to wet etching a wafer by scanning a nozzle across the wafer being rotated, teaches that the nozzle may be outside the wafer while not scanning (Fig. 1, [0046-0052]). Therefore, it would have been obvious to one of skill in the art to position the nozzle outside the wafer at the end of an etch operation because Yoshikawa is silent about a position of the nozzle at the end of an etching operation and Arai teaches that this would be effective.
Conclusion
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
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