Detailed Action
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 .
Response to Election/Restriction
Applicant’s election without traverse of Invention I in the reply filed on 1 March, 2026 is acknowledged.
Claims 14-20 withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected invention, there being no allowable generic or linking claim.
Claim Rejections 35 U.S.C. § 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, 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 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 1-4 and 7-11 and 13 are rejected under 35 U.S.C. 103 as being unpatentable over Kim et al. (US Pub. US 20050167778), hereinafter referred to as Kim, Schrems et al. (US Pub. 20040079990), hereinafter referred to as Schrems, Park (US Pub. 20170012098), hereinafter referred to as Park, and Su et al. (US Pub. 20120273948) hereinafter referred to as Su.
Regarding claim 1, Kim teaches forming an oxide layer in an isolation trench over a substrate (Kim, 125, Fig. 5, para. 44); forming a liner over the oxide layer (Kim, 130, Fig. 5, para. 44); oxidizing the liner (Kim, 131, Fig. 8, para 49).
Kim does not teach wherein oxidizing the liner is done by a plasma oxidation process at a temperature in a range between 25 ° C and 250 ° C, forming an implant region over the substrate after the liner is oxidized; etching the oxide layer and the liner after the implant region is formed; and forming a word line structure over the substrate and across the oxide layer and the liner.
However, Su teaches a method of plasma oxidation wherein the oxygen is subjected to RF energy and the process can be performed at lower temperatures, at least below 100.degree. C. and even as low as room temperature (Su, para. 25).
Therefore it would have been obvious to a person having ordinary skill in the art before the filing date of the invention to have utilized the plasma oxidation method of Su to oxidize the structure of Kim in order to provide the oxygen with higher oxidation energy (Su, para. 25) while simultaneously reducing the cost of heating the chamber and preventing heat-related damage to the substrate.
Additionally, Schrems teaches a method for forming an implant region (Schrems, para. 86) wherein a sacrificial oxide layer is grown to serve as a screen oxide during implantation. Schrems further states that the surface can be cleaned by cleaning with hydrofluoric acid (Schrems, para. 86).
Therefore it would have been obvious to one having ordinary skill in the art to combine the implantation and cleaning procedure of Schrems with the structure of Kim to prevent pitting or damage during the implantation procedure.
Further, Park teaches a buried gate structure, which may serve as a word line, formed through the upper portions of the active pattern (Park, 100b Fig. 2) the first oxide pattern (Park 114a, Fig 2, para. 81) and the second isolation structure (Park, 120b, Fig. 2, para. 81).
Therefore it would have been obvious to one having ordinary skill in the art before the filing date of the invention to combine the structure and etching method of Kim and Schrems with the word line of Park in order to improve isolation characteristics and reliability (Park, para. 82).
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Regarding claim 2, modified Kim teaches the method of claim 1, wherein the liner is oxidized to have an unoxidized lining portion and an oxidized lining portion over the unoxidized lining portion (Kim, 131, Fig. 8, para. 48), and the oxidized lining portion extends into the isolation trench (Kim, para. 48, see Fig. 8 above).
Regarding claim 3, modified Kim teaches the method of claim 1, further comprising: forming a semiconductor layer over the substrate and in the isolation trench (Kim, 140,Fig. 9, para. 54); wherein the liner is oxidized to have an unoxidized lining portion (Kim, 130, Fig. 9) and an oxidized lining portion (Kim, 131, Fig. 9) over the unoxidized lining portion, and the oxidized lining portion has a bottom surface lower than a top surface of the semiconductor layer (Kim, Fig. 9, 131 extends below the top of 140).
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Regarding claim 4, modified Kim teaches the method of claim 1, further comprising: forming a sacrificial oxide layer over the oxide layer and the liner after the liner is oxidized (Schrems, para. 86, not pictured), wherein the implant region is formed by an implantation process across the sacrificial oxide layer (Schrems, para. 86).
Regarding claim 7, modified Kim teaches the method of claim 1, but does not explicitly teach wherein the liner is an oxygen-free layer before the liner is oxidized.
Kim does acknowledge that oxidation of the liner before the deposition of the dielectric fill material would cause damage to the first oxide layer (Kim, para. 53). Further oxidation of the upper portion of the liner layer is performed at extremely low pressure (1mTorr-50 Torr, Kim, para. 50). Thus the presence of oxygen in the lower portion of the liner is not merely a process parameter but a result effective variable. If oxygen is allowed in the area, it could damage the first oxide layer. Because the prior art recognizes the presence of oxygen would directly affect the purpose of the liner the presence of oxygen is a result effective variable. Therefore it would have been obvious to one of obvious skill in the art before the filing date of the invention to minimize the presence of oxygen. Maintaining the liner as an oxygen free layer is a predictable result absent evidence of unexpected results (See MPEP 2144.05 II).
Regarding claim 8, Kim teaches a method comprising: forming a plurality of isolation trenches over a substrate (Kim, 102, Fig. 3, para. 39); forming a first oxide layer over the isolation trenches (Kim, 124, Fig. 5. Para. 44); forming a liner over the first oxide layer (Kim, 130, Fig. 5, para. 44); forming a second oxide layer over the liner (Kim, 135, Fig. 6, para. 46, and 140, Fig. 9); polishing the second oxide layer so that the first oxide layer and the liner are exposed (Kim, Fig. 19, para. 55); oxidizing the liner (Kim, 131, Fig. 8, para. 49).
Kim does not teach wherein oxidizing the liner is done by a plasma oxidation process at a temperature in a range between 25 ° C and 250 ° C , forming an implant region in the substrate; and forming a word line structure over the substrate and across the isolation trenches.
However, Su teaches a method of plasma oxidation wherein the oxygen is subjected to RF energy and the process can be performed at lower temperatures, at least below 100.degree. C. and even as low as room temperature (Su, para. 25).
Therefore it would have been obvious to a person having ordinary skill in the art before the filing date of the invention to have utilized the plasma oxidation method of Su to oxidize the structure of Kim in order to provide the oxygen with higher oxidation energy (Su, para. 25) while simultaneously reducing the cost of heating the chamber and preventing heat-related damage to the substrate.
Additionally, Schrems teaches a method for forming an implant region (Schrems, para. 86) wherein a sacrificial oxide layer is grown to serve as a screen oxide during implantation. Schrems further states that the surface can be cleaned by cleaning with hydrofluoric acid (Schrems, para. 86).
Therefore it would have been obvious to one having ordinary skill in the art to combine the implantation and cleaning procedure of Schrems with the structure of Kim to prevent pitting or damage during the implantation procedure.
Further, Park teaches a buried gate structure, which may serve as a word line, formed through the upper portions of the active pattern (Park, 100b Fig. 2) the first oxide pattern (Park 114a, Fig 2, para. 81) and the second isolation structure (Park, 120b, Fig. 2, para. 81).
Therefore it would have been obvious to one having ordinary skill in the art before the filing date of the invention to combine the structure and etching method of Kim and Schrems with the word line of Park in order to improve isolation characteristics and reliability (Park, para. 82).
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Regarding claim 9, modified Kim teaches the method of claim 8, wherein the liner is oxidized to have unoxidized lining portions (Kim, 130, Fig. 8, para. 49) and oxidized lining portions (Kim, para. 131, Fig. 8, para. 49) over the unoxidized lining portions, and the oxidized lining portions extend into the isolation trenches (Kim, Fig. 8, 131 extends into the trench).
Regarding claim 10, modified Kim teaches the method of claim 9, wherein after the word line structure is formed, the second oxide layer remains and is between the oxidized lining portions in one of the isolation trenches in a peripheral area free from the word line structure.
Because Park teaches the word line moving laterally across the word line structure (Park 120a, Fig. 2, para. 81) and the active pattern (Park, 100b, Fig. 2, para. 81) any portion of the isolation structure wherein the word line does not cross would remain untouched.
Regarding claim 11, modified Kim teaches the method of claim 8, further comprising:
forming a sacrificial oxide layer over the first oxide layer, the liner and the second oxide layer after the liner is oxidized (Schrems, para 86), wherein the implant region is formed by an implantation process across the sacrificial oxide layer (Schrems, para. 86).
Regarding claim 13, modified Kim teaches the method of claim 8, but does not explicitly teach wherein the liner is an oxygen-free layer before the liner is oxidized.
Kim does acknowledge that oxidation of the liner before the deposition of the dielectric fill material would cause damage to the first oxide layer (Kim, para. 53). Further oxidation of the upper portion of the liner layer is performed at extremely low pressure (1mTorr-50 Torr, Kim, para. 50). Thus the presence of oxygen in the lower portion of the liner is not merely a process parameter but a result effective variable. If oxygen is allowed in the area, it could damage the first oxide layer. Because the prior art recognizes the presence of oxygen would directly affect the purpose of the liner the presence of oxygen is a result effective variable. Therefore it would have been obvious to one of obvious skill in the art before the filing date of the invention to minimize the presence of oxygen. Maintaining the liner as an oxygen free layer is a predictable result absent evidence of unexpected results (See MPEP 2144.05 II).
Claims 5 and 6 are rejected under 35 U.S.C. 103 as being unpatentable over Kim, Schrems and Park as applied to claim 1 above, and further in view of Liao et al. (US Pub 20230230879), hereinafter referred to as Liao.
Regarding claim 5, modified Kim teaches the method of claim 1, but does not explicitly teach forming a hard mask over the oxide layer and the liner; patterning the hard mask so that the oxide layer and an oxidized lining portion of the liner is exposed; and etching a word line trench across the oxide layer and the liner based on the hard mask, wherein the word line structure is formed in the word line trench.
However, Liao teaches a method of forming word lines which includes a mask pattern (not shown for clarity) formed on the substrate (Liao, Fig.5, para. 41) and using an etch process (Liao, para. 41), and the word line structures are formed in the word line trenches (Liao, Figs. 5-14, paras. 92).
Therefore it would have been obvious to on having ordinary skill in the art before the filing date of the invention to combine the teachings of Kim, Schrems and Park with the word line creation method of Liao to create word lines to connect the various other semiconductor components.
Regarding claim 6, modified Kim teaches the method of claim 5, wherein the word line trench is etched so that an oxidized lining portion of the liner is cut off into a first portion and a second portion separated from each other.
Because Park teaches the word line moving laterally across the word line structure (Park 120a, Fig. 2, para. 81) and the active pattern (Park, 100b, Fig. 2, para. 81) any portion of the isolation structure wherein the word line does not cross would remain untouched, and because it cuts through the surface of the substrate, which is coplanar with the oxidized portion of the liner, it must therefore separate the oxidized portion of the liner into two separate portions.
Claim 12 is rejected under 35 U.S.C. 103 as being unpatentable over Kim, Schrems and Park as applied to claim 8 above, and further in view of Liao.
Regarding claim 12, modified Kim teaches the method of claim 8, but does not teach forming a hard mask over the first oxide layer and the liner; patterning the hard mask so that the first oxide layer and oxidized lining portions of the liner is exposed; and etching a word line trench across the first oxide layer and the liner based on the hard mask, wherein the word line structure is formed in the word line trench.
However, Liao teaches a method of forming word lines which includes a mask pattern (not shown for clarity) formed on the substrate (Liao, 101, Fig.5, para. 41) and using an etch process to form word line trenches (Liao, 501, Fig. 5,para. 41), and the word line structures are formed in the word line trenches (Liao, Figs. 5-14, paras. 92). Because the word line trench of Liao is formed through the substrate, and according to Park it is formed through the isolation structures, it must therefore go across the first oxide layer and the liner.
Therefore it would have been obvious to on having ordinary skill in the art before the filing date of the invention to combine the teachings of Kim, Schrems and Park with the word line creation method of Liao to create word lines to connect the various other semiconductor components.
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Response to Arguments
Applicant’s arguments, see page 7, line 13- page 9 line 2, filed, 7/15/2026, with respect to the rejections of claims 1-7 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 Su.
Applicant’s arguments were drawn to the plasma oxidation process wherein they added to claim 1 the process occurs between 25 °C and 250 °C. None of the previously cited sources utilized a plasma process at that temperature. However, Su details a plasma oxidation process using RF energy that takes place below 100° C. Applicant also argued that the high temperature plasma process of Kim would damage the substrate and damage the implant region of Schrem. This point is rendered moot by the inclusion of the low temperature plasma oxidation method of Su.
Applicant’s arguments, see 9, lines 3-12, filed 7/15/2026, with respect to the rejections of claims 8-13under 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 Su.
Applicant’s arguments were drawn to the plasma oxidation process wherein they added to claim 1 the process occurs between 25 °C and 250 °C. None of the previously cited sources utilized a plasma process at that temperature. However, Su details a plasma oxidation process using RF energy that takes place below 100° C. Applicant also argued that the high temperature plasma process of Kim would damage the substrate and damage the implant region of Schrem. This point is rendered moot by the inclusion of the low temperature plasma oxidation method of Su.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Sharangpani, (US Pub. 20170373079) teaches a method of making a memory device wherein plasma oxidation is used.
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). 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.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to KIERAN M CUNNINGHAM whose telephone number is (571)272-9654. The examiner can normally be reached Mon-Fri 7:30-5:00.
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/KIERAN M. CUNNINGHAM/Examiner, Art Unit 2893
/Britt Hanley/Supervisory Patent Examiner, Art Unit 2893
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