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 .
Claim Rejections - 35 USC § 103
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 (i.e., changing from AIA to pre-AIA ) 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.
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 text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
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.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1-4, 7, 10-13, 17 and 18 are rejected under 35 U.S.C. 103 as being unpatentable over DeVilliers ‘871 (US 2013/0309871, IDS 07/19/2023) and DeVilliers ‘904 (US 2021/0088904, IDS 07/19/2023).
Regarding Claims 1-4 and 7, DeVilliers ‘871 teaches methods of forming a masking pattern for an integrated circuit (abstract). Fig. 5A shows a patterned photoresist mandrels 430 formed on a hard mask layer 120, whereby the photoresist layer is exposed to a pattern of light directed through a photomask and soluble portions are moved with developer to form a positive or negative pattern (Examiner notes that each of these photoresists contain solubility-shifting agents) (paragraph [0059, 0096]).
DeVilliers ‘871 discloses that a chemically activated species 432 is deposited using a spin-on deposition on the structure shown in Fig. 5A (Claim 7), such as an acid or base solution, which alters the solubility of the top and side regions 452 and 454 of the mandrels 430 upon applying a baking step (Claim 4) (corresponding to diffusing the dye into the photoresist pattern resulting in diffusion regions) (paragraph [0098-0099]). The chemically active species may be an acid such as a conventional photoresist PAG or other organic acid (paragraph [0063]). While DeVilliers ‘871 is silent to explicitly removing the first overcoat from the substrate, it is clear from Fig. 5A to Fig. 5B that the acid coating is applied and the excess acid is removed. DeVilliers ‘871 further discloses various processes can be adapted for forming mandrels and second masking layers, which includes spin-on deposition (Claim 7).
DeVilliers ‘871 discusses utilizing a bake to drive an acid- or base-catalyzed reaction that alters the solubility of portions of the mandrels (paragraph [0099]).
DeVilliers ‘871 is silent to activating the solubility-shifting agent in the diffusion regions of the photoresist pattern using a second actinic radiation.
However, DeVilliers ‘904 teaches a method of forming a pattern on a substrate (abstract). In step S204, the solubility-shifting material (grafting material) is diffused by a predetermined distance into an abutting portion of the filler material so that the solubility-shifting material changes solubility of the abutting portion of the filler in a specific developer (paragraph [0037]). Furthermore, the solubility-shifting material may be a thermal acid generator activated with heat or a photoacid acid generator activated with exposure to actinic radiation (paragraph [0011]). The thermal or photoacid generator does not necessarily need to be activated prior to diffusing the solubility shifting material into the abutting portion (paragraph [0037]).
Both DeVilliers ‘871 and DeVilliers ‘904 disclose methods of diffusing acid components into resist layers in order to modify the solubility of specific regions the resist layers and therefore are analogous art. It would have been obvious for one of ordinary skill in the art to have modified the method of DeVilliers ‘871 with the method of activating the diffused photoacid generator using an exposure to actinic radiation disclosed in DeVilliers ‘904 through routine experimentation. One of ordinary skill would reasonably expect this modification to enable activation of the solubility-shifting agents using a second actinic radiation and arrive at the instantly claimed invention.
DeVilliers ‘871 further teaches depositing a second masking layers 440 over the anti-spacers 450 and developing the solubility-shifted regions to form the structure shown in Fig. 5D; the second overcoat is insoluble in the developer as the regions 448 are remaining after development (Fig. 5C, 5D, paragraph [0100-0104]) (Claim 2). After Fig. 5D, the steps to transfer the pattern into the target layer may be followed (paragraph [0104]) (Claim 3).
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Regarding Claims 10-13 and 18, DeVilliers ‘871 teaches methods of forming a masking pattern for an integrated circuit (abstract). Fig. 5A shows a patterned photoresist mandrels 430 formed on a hard mask layer 120, whereby the photoresist layer is exposed to a pattern of light directed through a photomask and soluble portions are moved with developer to form a positive or negative pattern (Examiner notes that each of these photoresists contain solubility-shifting agents) (paragraph [0059, 0096]).
DeVilliers ‘871 discloses that a chemically activated species 432 is deposited using a spin-on deposition on the structure shown in Fig. 5A (Claim 18), such as an acid or base solution, which alters the solubility of the top and side regions 452 and 454 of the mandrels 430 upon applying a baking step (Claim 13) (corresponding to diffusing the dye into the photoresist pattern resulting in diffusion regions) (paragraph [0098-0099]). The chemically active species may be an acid such as a conventional photoresist PAG or other organic acid (paragraph [0063]). While DeVilliers ‘871 is silent to explicitly removing the first overcoat from the substrate, it is clear from Fig. 5A to Fig. 5B that the acid coating is applied and the excess acid is removed. DeVilliers ‘871 further discloses various processes can be adapted for forming mandrels and second masking layers, which includes spin-on deposition (paragraph [0043]) (Claim 18).
Regarding the limitation diffusing the solubility agent into the second overcoat resulting in a second diffusion region in the second overcoat, DeVilliers ‘871 further discloses in Fig. 4B a chemically active species such as an acid solution is deposited on the patterned photoresist structure of Fig. 4A to diffuse the acid into at least portions of the top and side regions of mandrels 330 (paragraph [0086]); the resist layer 340 is formed over the mandrels, and after applying a baking step the chemically active diffuses from the mandrels to form anti-spacer region 350 (paragraph [0088]).
Regarding the limitation diffusing the solubility agent into the second overcoat resulting in a second diffusion region in the second overcoat, DeVilliers ‘871 further discloses in Fig. 4B a chemically active species such as an acid solution is deposited on the patterned photoresist structure of Fig. 4A to diffuse the acid into at least portions of the top and side regions of mandrels 330 (paragraph [0086]); the resist layer 340 is formed over the mandrels, and after applying a baking step the chemically active diffuses from the mandrels to form anti-spacer region 350 (paragraph [0088]).
DeVilliers ‘871 discusses utilizing a bake to drive an acid- or base-catalyzed reaction that alters the solubility of portions of the mandrels (paragraph [0099]).
DeVilliers ‘871 is silent to activating the solubility-shifting agent in the diffusion regions of the photoresist pattern using a second actinic radiation.
However, DeVilliers ‘904 teaches a method of forming a pattern on a substrate (abstract). In step S204, the solubility-shifting material (grafting material) is diffused by a predetermined distance into an abutting portion of the filler material so that the solubility-shifting material changes solubility of the abutting portion of the filler in a specific developer (paragraph [0037]). Furthermore, the solubility-shifting material may be a thermal acid generator activated with heat or a photoacid acid generator activated with exposure to actinic radiation (paragraph [0011]). The thermal or photoacid generator does not necessarily need to be activated prior to diffusing the solubility shifting material into the abutting portion (paragraph [0037]).
Both DeVilliers ‘871 and DeVilliers ‘904 disclose methods of diffusing acid components into resist layers in order to modify the solubility of specific regions the resist layers and therefore are analogous art. It would have been obvious for one of ordinary skill in the art to have modified the method of DeVilliers ‘871 with the method of activating the diffused photoacid generator using an exposure to actinic radiation disclosed in DeVilliers ‘904 through routine experimentation. One of ordinary skill would reasonably expect this modification to enable activation of the solubility-shifting agents using a second actinic radiation and arrive at the instantly claimed invention.
Regarding Claim 17, the discussion of Claim 10 is relied upon as above. DeVilliers ‘871 further teaches in Fig 9A-D applying a spacer layer over the exposed surfaces of the first pattern and then etching to remove the first pattern leaving behind the spacers that were applied over the first pattern (paragraph [0134-0143]). Any suitable selective etch process can be used (paragraph [0145]). The spacers here aid in modifying the pitch, such that the pitches formed from the masking pattern are smaller (paragraph [0134]).
While the process in Fig. 9 utilizing an etching step which is different from the developing step used in Fig. 5 mentioned above, it would have been obvious for one of ordinary skill in the art to have combined the methods disclosed in Fig. 5 and Fig. 9 of DeVilliers ‘871 through routine experimentation. One of ordinary skill would have been motivated to make this modification to form smaller pitches in the masking pattern as suggested by DeVilliers ‘871.
Claims 5, 8, 14, and 19 are rejected under 35 U.S.C. 103 as being unpatentable over DeVilliers ‘871 (US 2013/0309871, IDS 07/19/2023) and DeVilliers ‘904 (US 2021/0088904, IDS 07/19/2023) as applied to Claims 1 and 10 in view of Andou (US 2012/0231396).
Regarding Claims 5, 8, 14, and 19, DeVilliers ‘904 further discloses in an embodiment where the acid functional group is a photoacid generator, an actinic radiation (e.g. flood exposure or patterned exposure at a particular wavelength which the second photoresist material is insensitive to) is performed for activation and a subsequent bake for diffusion (paragraph [0048]).
DeVilliers ‘871 further discloses The acid solution can include an acid such as a conventional photo resist PAG or other organic acid (paragraph [0063]).
DeVilliers ‘871 and DeVilliers ‘904 are silent to particular features of the second actinic radiation or the radiation wavelength the photoacid generator is susceptible to and silent to the composition of the photoresist.
Andou teaches a method for producing a resin pattern comprising coating the photosensive resin, removing solvent, an exposure step, a developing step, an overcoating step, a heat treatment step, and removing the overcoat layer (paragraph 0012-0018]). The photosensitive resin composition further comprises a polymer, a photoacid generator and a solvent (paragraph [0023]). Furthermore, known additives may be added such as an acid amplifier and a basic compound (corresponding to a quencher) (paragraph [0338-0340]). The resin contains an phenolic hydroxyl group protected with an acid decomposable group (paragraph [0127]). The photoacid generator is preferably a compound which generates an acid in response to active radiation having a wavelength of 300 to 450 nm, and may include various sulfonium salts, iodonium salts, ammonium salts, diazomethane compounds, imidosulfonate compounds, and oxime sulfonate compounds (paragraph [0234-0236]).
Furthermore, regarding the second actinic radiation having a wavelength between 13.5 nm and 365 nm, the photoacid generators of Andou preferably react in response to a wavelength of 300 to 450 nm. The photoresist of Andou is compatible with the wavelengths 300 to 450 nm, which overlaps the claimed range. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976).
DeVilliers ‘871, DeVilliers ‘904, and Andou all teach patterning methods in lithography comprising photoresist and overcoat layers. DeVilliers ‘871 and DeVilliers ‘904 note an acid or photoacid generator are used to diffuse into the line regions and are merely silent to particular exposure wavelengths that may activate them. Thus, it would have been obvious for one of ordinary skill in the art to have modified the diffusible acids or photoacid generator of DeVilliers ‘871 and DeVilliers ‘904 with the photoacid generator disclosed in Andou through routine experimentation. One of ordinary skill would reasonably expect substituting one photoacid generator for another to perform the same function.
Regarding the photoresist composition, DeVilliers ‘871, DeVilliers ‘904, and Andou all teach patterning methods in lithography comprising photoresist and overcoat layers. DeVilliers ‘871 and DeVilliers ‘904 are merely silent to the composition of the photoresist therein. It would have been obvious for one of ordinary skill in the art to have modified the photoresist composition with the particular composition of Andou containing a resin with an acid decomposable group, a photoacid generator, and a quencher through routine experimentation. The resin of Andou is exposed, developed, and coated with an overcoat similar to the methods disclosed in DeVilliers ‘871 and DeVilliers ‘904. One of ordinary skill would reasonably expect this modification to produce a composition compatible with DeVilliers ‘871 and DeVilliers ‘904.
Claims 6, 9, 15, and 20 are rejected under 35 U.S.C. 103 as being unpatentable over DeVilliers ‘871 (US 2013/0309871, IDS 07/19/2023) and DeVilliers ‘904 (US 2021/0088904, IDS 07/19/2023) as applied to Claims 1 and 10 in view of Osaki (US 2015/0010866).
Regarding Claims 6, 9, 15, and 20, DeVilliers ‘904 further discloses in an embodiment where the acid functional group is a photoacid generator, an actinic radiation (e.g. flood exposure or patterned exposure at a particular wavelength which the second photoresist material is insensitive to) is performed for activation and a subsequent bake for diffusion (paragraph [0048]).
DeVilliers ‘871 discloses that a chemically activated species 432 is deposited using a spin-on deposition on the structure shown in Fig. 5A, such as an acid or base solution, which alters the solubility of the top and side regions 452 and 454 of the mandrels 430 upon applying a baking step (paragraph [0098-0099]). DeVilliers ‘871 further discloses the acid solution can include an acid such as a conventional photo resist PAG or other organic acid (paragraph [0063]).
Examiner notes that the photoacid generator of DeVilliers ‘871 and DeVilliers ‘904 is equivalent to the claimed dye.
DeVilliers ‘871 and DeVilliers ‘904 are silent to the dye includes an acid amplifier.
Osaki teaches that the acid amplifier is a component that is stable in the absence of an acid but is decomposed in the presence of an acid due to a catalytic reaction to produce a protonic acid (paragraph [0190]). Since the decomposition reaction is promoted as the amount of protonicacid produced increases, production of the protonic acid is amplified (paragraph [01290]). When the photoresist includes the acid amplifier, a large amount of protonic acid can be produced as compared with the case where the protonic acid is merely generated by the acid generator upon exposure (paragraph [0190]). This makes it possible to form a large amount of cationic groups and improve the dissolution contrast between the exposed area and the unexposed area (paragraph [0190]).
While Osaki does not demonstrate the use of an acid amplifier with a photoacid generator in the same way as disclosed in DeVilliers ‘871 or DeVilliers ‘904, it is clear that the combination of a photoacid generator and acid amplifier increases the amount of acid produced thereby improving dissolution due to switching the solubility of the polymer. Further, since the acid amplifier catalytically produced large amount of protonic acid as compared with just the photoacid generator alone, fewer PAG-photon interactions would be needed to facilitate dissolution of the photoresist.
It would have been obvious for one of ordinary skill in the art to have modified the diffusible acid of DeVilliers ‘871 and DeVilleirs ‘904 to further contain the acid amplifier of Osaki. One of ordinary skill would have been motivated to make this modification to improve the dissolution contrast due to the interaction of the photoacid generator and acid amplifier as suggested by Osaki.
Claim 16 is rejected under 35 U.S.C. 103 as being unpatentable over DeVilliers ‘871 (US 2013/0309871, IDS 07/19/2023) and DeVilliers ‘904 (US 2021/0088904, IDS 07/19/2023) as applied to Claim 10 in view of Kohl (US 2013/0011784).
Regarding Claim 16, the discussion of Claim 10 is relied upon as above. DeVilliers ‘871 further discloses that three dimensional structures can be formed by the methods therein which can include but are not limited to lines, trenches, vias, pillars, posts, troughs, and moats (paragraph [0146]). Further, Referring to FIG. 5C, a second masking layer 440 is blanket deposited over the anti-spacers 450 and the exposed surfaces 122 of the hard mask layer 120 (paragraph [0101]). Referring to FIG. 5D, the structure resulting from the step of FIG. 5C is subjected to development and any suitable developer may be used to remove the anti-spacers 450 (paragraph [0103]).
DeVilliers ‘871 and DeVilliers ‘904 are silent to forming air-gap structures.
However, Kohl teaches a process for forming air-gap structures in Fig. 11A-11G (paragraph [0062]). The process involves applying an overcoat to fill in the regions between the unexposed region 40 plus a thickness of overcoat overlying above the top surface of the photoresist layer as shown in Fig. 11E-11F. The method particularly utilizes thermal decomposition step that selectively removes the unexposed regions 40 in order to form the airgap 55 underneath the overcoat layer (paragraph [0062]).
DeVilliers ‘871 teaches methods of applying a second masking layer blanket exposed over the anti-spacers and Kohl teaches methods of applying an overcoat overlying a top surface of the unexposed region and therefore are analogous semiconductor art. Both references apply a similar overcoat layer over a patterned spacer or unexposed region. DeVilliers ‘871 using a developing step to remove the anti-spacer material while Kohl uses a thermal decomposition step to remove the unexposed region; both references utilize a removal process to form different structures.
It would have been obvious for one of ordinary skill in the art to have modified the thickness of the second masking layer in DeVilliers ‘871 with the overcoat layer of Kohl to apply a thickness above the top surface of the unexposed region through routine experimentation. Applying this modification to Kohl process that uses a developing process to remove the spacers would result in a developing process that forms air-gap structures after development. One of ordinary skill would reasonably expect this modification to form air-gap structures within the patterned features.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to KEVIN JAMES DRUMMEY whose telephone number is (703)756-5419. The examiner can normally be reached Monday - Friday 7:30am-5:00pm EST.
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/K.J.D./Examiner, Art Unit 1737
/JONATHAN JOHNSON/Supervisory Patent Examiner, Art Unit 1734