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 § 103
Claims 1-7, 9-11, and 21 are rejected under 35 U.S.C. 103 as being unpatentable over Cho (PGPub 20210202547) in further view of Holden (US Patent No. 8883615), Oh (PGPub No. 20150287590), and Lim (PGPub No. 20120214298).
Regarding claim 1, Cho teaches a method of fabricating an Image sensor, comprising: providing a semiconductor substrate having a first surface and a second surface that are opposite to each other (Fig. 6A-6B and [0065] point to a substrate 100 comprising a first surface 100a and a second surface 100b.); forming a mask pattern on the first surface, the mask pattern having an opening ([0065] points to forming a mask pattern (not shown) on the first surface 100a, which may have openings.); and performing an etching process using the mask pattern to form a pixel isolation trench extending from the first surface towards the second surface (Figs. 6A-6B and [0065] point to trenches 130T, defined in position and shape by the openings in the mask pattern, which are used to define and isolate a plurality of pixel regions PXR.).
Cho fails to teach supplying a first fluid in the opening; vaporizing the first fluid to remove the first fluid on the semiconductor substrate; supplying a second fluid in the pixel isolation trench; replacing the second fluid in the pixel isolation trench with a third fluid; vaporizing the third fluid, wherein the third fluid has a surface tension that is lower than a surface tension of the first fluid; and wherein the mask pattern is present after the first fluid is vaporized.
Holden teaches supplying a first fluid in the opening (Fig. 4C-4D and Col. 10, lines 35-44 point to the formation of a semiconductor wafer comprising a laser etch mask 418 with openings 420, removing said mask via a cleaning technique which involves immersion in a solvent bath followed by rinsing and Maragoni effect isopropyl alcohol (IPA) (first fluid) drying.); and vaporizing the first fluid to remove the first fluid on the semiconductor substrate (It is considered obvious that a cleaning process would not be done under a temperature which would sublimate isopropyl alcohol.). Thus, it would have been obvious for a person of ordinary skill in the art (POSITA) prior to the filing date to combine the teachings of Cho and Holden, such that isopropyl alcohol is used to clean the opening of the mask pattern in order to remove any contaminants before continuing the fabrication process.
Cho et al. still fails to teach supplying a second fluid in the pixel isolation trench; replacing the second fluid in the pixel isolation trench with a third fluid; and vaporizing the third fluid, wherein the third fluid has a surface tension that is lower than a surface tension of the first fluid; and wherein the mask pattern is present after the first fluid is vaporized.
Oh teaches supplying a second fluid in the pixel isolation trench ([0036] points to a rinse solution including isopropyl alcohol (second fluid; this corresponds with claim 10 of the claimed invention) that may be supplied to the pattern-formed substrate (pixel isolation trench).); replacing the second fluid in the pixel isolation trench with a third fluid (claim 1 points to injecting supercritical carbon dioxide (third fluid; this corresponds with claim 5 of the claimed invention) such that rinse solution remaining on the pattern is diluted (replacing the second fluid).); and vaporizing the third fluid (This is interpreted as inherent characteristic; supercritical carbon dioxide, or SCCO2, naturally vaporizes at room temperature.), wherein the third fluid has a surface tension that is lower than a surface tension of the first fluid ([0018] points to lowering the surface tension of the cleaning solution (rinse solution/second fluid) by diluting said solution with SCCO2.). Thus, it would have been obvious for a POSITA prior to the filing date to combine the teachings of Cho et al. and Oh, such that the newly etched pixel isolation trench undergoes cleaning, first with an additional use of isopropyl alcohol to generally remove any particulates or contaminants, and finally with SCCO2 to provide more detailed cleaning, removing any residue or etch byproducts without damaging the pixel isolation trench.
Cho et al. still fails to teach wherein the mask pattern is present after the first fluid is vaporized.
Lim teaches wherein the mask pattern is present after the first fluid is vaporized ([0010] points to a method of manufacturing non-volatile memory devices comprising forming mask patterns on stack layers; repeating a dry etch process and a wet cleaning process in order to etch the stack layer exposed between the mask patterns up to a first depth. [0021] further points to the supplying/use of isoprophil alcohol (IPA) (first fluid) for the wet cleaning process.). Thus, it would have been obvious for a POSITA prior to the filing date to combine the teachings of Cho et al. and Oh, such that the mask pattern is present after the first fluid is vaporized in order to maintain a selective level of protection during later dry etch and wet cleaning processes.
Regarding claim 2, Oh teaches wherein the vaporizing of the third fluid is performed under a pressure that is higher than a pressure for the vaporizing of the first fluid ([0038] points to the SCCO2 (third fluid) being at a pressure of 74.8 bar or higher.). Thus, it would have been obvious for a POSITA prior to the filing date to combine the teachings of Cho et al. and Oh, such that the third fluid is vaporized at a higher pressure in order to prevent any defects such as pattern leaning.
Regarding claim 3, Oh teaches wherein the replacing of the second fluid with the third fluid comprises dissolving the second fluid in the third fluid (claim 1 points to injecting supercritical carbon dioxide (third fluid; this corresponds with claim 5 of the claimed invention) such that rinse solution (second fluid) remaining on the pattern is diluted (dissolving the second fluid).). Thus, it would have been obvious for a POSITA prior to the filing date to combine the teachings of Cho et al. and Oh, such that the second fluid is diluted/dissolved in the third fluid in order to lower the surface tension of the second fluid.
Regarding claim 4, Oh teaches wherein the vaporizing of the third fluid comprises: applying a first pressure to the third fluid, the first pressure is higher than atmospheric pressure ([0038] points to the SCCO2 (third fluid) being at a pressure of 74.8 bar or higher.); and applying a second pressure that is lower than the first pressure to the third fluid (It is interpreted as obvious that the third fluid would eventually be brought to average room pressure (second pressure), which is 1 atm or 1.01325 bar.). Thus, it would have been obvious for a POSITA prior to the filing date to combine the teachings of Cho et al. and Oh, such that the third fluid is vaporized via a pressure that is higher than atmospheric pressure in order to prevent any defects such as pattern leaning.
Regarding claim 5, Oh teaches wherein the third fluid comprises carbon dioxide in a supercritical state (claim 1 points to injecting supercritical carbon dioxide (third fluid).). Thus, it would have been obvious for a POSITA prior to the filing date to combine the teachings of Cho et al. and Oh, such that the third fluid is supercritical carbon dioxide in order to lower the surface tension of the cleaning solution/second fluid.
Regarding claim 6, Cho teaches wherein: the first surface and the second surface are spaced apart from each other in a first direction (Fig. 6A-6B, [0050], and [0065] point to a substrate 100 comprising a first surface 100a and a second surface 100b, which are shown to be spaced apart in a third direction D3 (first direction).); and a length of the opening in the first direction is less than a length of the pixel trench ([0065] points to forming a mask pattern (not shown) on the first surface 100a, which may have openings, as well as trenches 130T (pixel trench). Although not show, it is obvious that the length of the opening in the direction D3 (first direction) is less than the length of the trenches 130T because the opening is formed only in the mask pattern located on the first surface 100a, while the trenches 130T are shown to extend from the first surface 100a down towards the second surface 100b.).
Regarding claim 7, Oh teaches loading the semiconductor substrate in a drying chamber before the replacing of the second fluid with the third fluid ([0037] and [0038] point to the pattern-formed substrate (semiconductor substrate) first being transferred to a dry chamber (drying chamber) before the SCCO2 (third fluid) is injected.). Thus, it would have been obvious for a POSITA prior to the filing date to combine the teachings of Cho et al. and Oh, such that the substrate is placed into a drying chamber prior to introducing the third fluid in order to maintain an atmospheric pressure.
Regarding claim 9, Cho teaches performing an etching process on the mask pattern to increase a width of the opening ([0065] points to a mask pattern (not shown) on the first surface 100a with openings which define the positions and shapes of the trenches 130T, where said mask pattern is used as an etch mask to etch the substrate 100. Due to the final shape of the trenches 130T as shown in Figs. 6A-6B, where the width of said trenches gets larger towards the first surface 100a and by extension the etched mask pattern/etch mask, it is considered obvious that one of ordinary skill in the art would perform an additional etching process to increase the width of the openings, as doing so would allow easier access to the underlying substrate and make it easier to perform the initial etching process that forms the trenches.).
Regarding claim 10, Oh teaches wherein the second fluid includes isopropyl alcohol ([0036] points to a rinse solution (second fluid) including isopropyl alcohol.). Thus, it would have been obvious for a POSITA prior to the filing date to combine the teachings of Cho et al. and Oh, such that the second fluid includes isopropyl alcohol in order to utilize the cleaning/rinsing properties commonly known to isopropyl alcohol.
Regarding claim 11, Oh teaches wherein the supplying of the second fluid is performed using a spin-on-process ([0008 points to supplying a rinse solution including isopropyl alcohol (second fluid) while the substrate is rotated by the spin module (spin-on-process).). Thus, it would have been obvious for a POSITA prior to the filing date to combine the teachings of Cho et al. and Oh, such that a spin-on-process is applied to the second fluid in order to lower the surface tension of the isopropyl alcohol and by extension avoid pattern leaning.
Regarding claim 21, Holden teaches wherein the performing an etching process occurs after the vaporizing the first fluid (Fig. 4C-4E and Col. 10, lines 35-44 point to the formation of a semiconductor wafer comprising a laser etch mask 418 with openings 420, removing said mask via a cleaning technique which involves immersion in a solvent bath followed by rinsing and Maragoni effect isopropyl alcohol (IPA) (first fluid) drying, which is then followed by the formation of trench extensions 428 formed via a plasma etch. It is considered obvious that a cleaning process would not be done under a temperature which would sublimate isopropyl alcohol.). Thus, it would have been obvious to a POSITA prior to the filing date of the claimed invention to combine the teachings of Cho et al. and Holden, such that the etching process occurs after the first fluid is vaporized in order to remove particles and other contaminants which could otherwise adversely affect the etching process.
Claims 8 is rejected under 35 U.S.C. 103 as being unpatentable over Cho et al. in further view of Toda (PGPub No. 20150228693).
Regarding claim 8, Toda teaches performing an ion implantation process in the pixel isolation trench (Fig. 13C and [0217] points to the pixel isolation section 53 (pixel isolation trench) being formed by ion-implanting.). Thus, it would have been obvious to a POSITA prior to the filing date of the claimed invention to combine the teachings of Cho et al. and Toda, such that the pixel isolation trench is formed via an ion implantation process in order to form a higher impurity concentration.
Response to Arguments
Applicant’s arguments, see Remarks, filed 03/11/2026, with respect to the rejection(s) of claim(s) 1 under 35 U.S.C. §103 have been fully considered and are persuasive. Therefore, the rejection has been withdrawn. However, upon further consideration, a new ground(s) of rejection is made in view of Cho et al. in further view of Lim (PGPub No. 20120214298).
Conclusion
THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
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 nonprovisional extension fee (37 CFR 1.17(a)) 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.
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/PATRICK CULLEN/Assistant Examiner, Art Unit 2899 /DALE E PAGE/Supervisory Patent Examiner, Art Unit 2899
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