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 § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claims 1, 2, 5, 10, 11, 13-17, 19, and 20 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Hausmann et al. (2013/0189854, hereafter Hausmann).
Regarding claim 1, Hausmann discloses a method of depositing a silicon nitride layer on a semiconductor substrate, the method comprising:(a) in a process chamber (1302, Fig. 5, par. 0085), exposing the semiconductor substrate (1312, Fig. 5, par. 0090; 205, Fig. 2, par. 0056) to a halogen-free silicon-containing precursor (par. 0029), wherein the silicon-containing precursor further includes at least one nitrogen (N) atom (par. 0025), to form an adsorbed layer of the silicon-containing precursor on the semiconductor substrate (par. 0040); and(b) in the same process chamber, treating the semiconductor substrate with a plasma formed in a process gas comprising nitrogen (N2) (par. 0041) to convert the adsorbed layer of the silicon-containing precursor to silicon nitride (par. 0069), wherein the conversion of the adsorbed layer of the silicon-containing precursor to silicon nitride is performed at a temperature of between about 300 degrees C and about 750 degrees C (par. 0069) and a pressure of at least about 15 Torr (par. 0056).
Regarding claim 2, Hausmann discloses a method wherein the semiconductor substrate comprises a recessed feature (par. 0056), and wherein the silicon nitride layer is deposited in the recessed feature with a conformality of at least about 80% (par. 0082).
Regarding claim 5, Hausmann discloses a method wherein the conversion of the adsorbed layer of the silicon-containing precursor to silicon nitride is performed (par. 0056) at a temperature of between about 400 degrees C and about 750 degrees C (par. 0069) and a pressure of between about 15 Torr and about 30 Torr (par. 0056).
Regarding claim 10, Hausmann discloses a method further comprising purging the process chamber to remove the unadsorbed silicon-containing precursor between (a) and (b) (par. 0057).
Regarding claim 11, Hausmann discloses a method wherein the semiconductor substrate comprises a recessed feature with an aspect ratio of at least 5:1 (par. 0056), and wherein the silicon nitride is deposited conformally to a thickness of at least 100 A (par. 0058).
Regarding claim 13, Hausmann discloses a method wherein the halogen- free silicon-containing precursor is selected from the group consisting of di(methylamino)silane (DMAS), di(ethylamino)silane (DEAS), di(propylamino)silane (DPAS), di(isopropylamino)silane (DIPAS), di(sec-butylamino)silane (DSBAS), bis-(t-butylamino)silane (BTBAS), and tris(dimethylamino)silane (TDMAS) (par. 0024).
Regarding claim 14, Hausmann discloses a method further comprising the steps of: applying photoresist to the semiconductor substrate; exposing the photoresist to light; patterning the photoresist and transferring the pattern to the semiconductor substrate; and selectively removing the photoresist from the semiconductor substrate (par. 0116).
Regarding claim 15, Hausmann discloses an apparatus for processing a substrate, the apparatus comprising:(a) a process chamber (1302, Fig. 5, par. 0085) configured for housing the substrate (1312, Fig. 5, par. 0090; 205, Fig. 2, par. 0056), wherein the process chamber includes a substrate holder (1308, Fig. 5, par. 0090) configured to hold the substrate and an inlet (1320, Fig. 5) configured to introduce one or more reactants to the process chamber (par. 0086);(b) a mechanism for generating a plasma (2402/2404, Fig. 6, par. 0100); and(c) a controller (par. 0084) comprising program instructions configured to effect deposition of a silicon nitride layer on the substrate (par. 0029) by causing:(i) in the process chamber, exposing the substrate to a halogen-free silicon-containing precursor (par. 0029), wherein the silicon-containing precursor further includes at least one nitrogen (N) atom (par. 0025), to form an adsorbed layer of the silicon-containing precursor on the semiconductor substrate (par. 0040); and (ii) in the same process chamber, treating the substrate with a plasma formed in a process gas comprising nitrogen (N2) to convert the adsorbed layer of the silicon-containing precursor to silicon nitride (par. 0041), wherein the conversion of the adsorbed layer of the silicon-containing precursor to silicon nitride is performed at a temperature of between about 300 2C and about 750 2C (par. 0069) and a pressure of at least about 15 Torr (par. 0056).
Regarding claim 16, Hausmann discloses an apparatus wherein the pressure is between about 15 Torr and about 30 Torr (par. 0056).
Regarding claim 17, Hausmann discloses an apparatus wherein the temperature is between about 400 degrees C and about 750 degrees C (par. 0069).
Regarding claim 19, Hausmann discloses an apparatus wherein the halogen-free silicon-containing precursor is selected from the group consisting of di(methylamino)silane (DMAS), di(ethylamino)silane (DEAS), di(propylamino)silane (DPAS), di(isopropylamino)silane (DIPAS), di(sec- butylamino)silane (DSBAS), bis-(t-butylamino)silane (BTBAS), and tris(dimethylamino)silane (TDMAS) (par. 0024).
Regarding claim 20, Hausmann discloses an apparatus wherein the program instructions are configured to cause conformal deposition of the silicon nitride in a recessed feature (par. 0056) with a conformality of at least about 80% (par. 0082).
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, 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.
Claims 3, 4, 6, 7, and 22 are rejected under 35 U.S.C. 103 as being unpatentable over Hausmann in view of Chen et al. (2019/0259598, hereafter Chen).
Regarding claim 3, Hausmann discloses method wherein the semiconductor substrate comprises a recessed feature (par. 0056), wherein the silicon nitride layer is deposited in the recessed feature with a conformality of at least about 80% (par. 0082).
Hausmann fails to disclose wherein the deposited silicon nitride has a wet etch rate (WER) in 100:1 hydrofluoric acid of less than about 3 A/minute.
However, Chen teaches wherein the deposited silicon nitride has a wet etch rate (WER) in 100:1 hydrofluoric acid of less than about 3 A/minute (par. 0069).
It would have been obvious to one of ordinary skill in the art at the time the invention was filed to modify Hausmann with Chen by providing a wet etch rate in hydrofluoric acid of less than three angstroms per minute in order to establish a highly dense film acting as an etch stop or masking layer with highly effective resistance.
Regarding claim 4, Hausmann discloses a method wherein the semiconductor substrate comprises a recessed feature (par. 0056), wherein the silicon nitride layer is deposited in the recessed feature with a conformality of at least 90% (par. 0082).
Hausmann fails to disclose wherein the deposited silicon nitride has a wet etch rate (WER) in 100:1 hydrofluoric acid of less than about 2 A/minute.
However, Chen teaches wherein the deposited silicon nitride has a wet etch rate (WER) in 100:1 hydrofluoric acid of less than about 2 A/minute (par. 0069).
It would have been obvious to one of ordinary skill in the art at the time the invention was filed to modify Hausmann with Chen by providing a wet etch rate in hydrofluoric acid of less than two angstroms per minute in order to establish greater effectiveness in a highly dense film acting as an etch stop or masking layer with high resistance.
Regarding claim 6, Hausmann discloses wherein the process gas further includes a noble gas (par. 0041).
Hausmann fails to disclose wherein N2 content in the process gas is less than about 10% by volume.
However, Chen teaches wherein N2 content in the process gas is less than about 10% by volume (par. 0032).
It would have been obvious to one of ordinary skill in the art at the time the invention was filed to modify Hausmann with Chen by providing a nitrogen gas concentration of less than 10% by volume in order to prevent film dilution and ensure efficient plasma dissociation of reactants.
Regarding claim 7, Hausmann discloses a method wherein the process gas further includes a noble gas (par. 0041).
Hausmann fails to disclose wherein N2 content in the process gas is less than about 5% by volume.
However, Chen teaches wherein N2 content in the process gas is less than about 5% by volume (par. 0032).
It would have been obvious to one of ordinary skill in the art at the time the invention was filed to modify Hausmann with Chen by providing a nitrogen gas concentration of less than 5% by volume in order to prevent film dilution and ensure efficient plasma dissociation of reactants.
Regarding claim 22, Hausmann discloses a method of depositing a silicon nitride layer on a semiconductor substrate, the method comprising: (a) in a process chamber (1302, Fig. 5, par. 0085), exposing the semiconductor substrate (1312, Fig. 5, par. 0090; 205, Fig. 2, par. 0056) to a halogen-free silicon-containing precursor (par. 0029), wherein the silicon-containing precursor further includes at least one nitrogen (N) atom (par. 0025), to form an adsorbed layer of the silicon-containing precursor on the semiconductor substrate (par. 0040); and (b) in the same process chamber, treating the semiconductor substrate with a plasma formed in a process gas comprising nitrogen (N2) (par. 0041) to convert the adsorbed layer of the silicon-containing precursor to silicon nitride (par. 0069), wherein the conversion of the adsorbed layer of the silicon-containing precursor to silicon nitride is performed at a temperature of between about 300 degrees C and about 750 degrees C (par. 0069).
Hausmann fails to disclose wherein the content of N2 in the process gas is less than about 10%.
However, Chen teaches wherein the content of N2 in the process gas is less than about 10% (par. 0032).
It would have been obvious to one of ordinary skill in the art at the time the invention was filed to modify Hausmann with Chen by providing a concentration of nitrogen gas of less than about 10% by volume in order to prevent film dilution and ensure efficient plasma dissociation of reactants.
Claim 8 is rejected under 35 U.S.C. 103 as being unpatentable over Hausmann in view of Kagaya (2022/0403515, hereafter Kagaya).
Regarding claim 8, Hausmann, discussed above, fails to disclose a method wherein the deposited silicon nitride is substantially hydrogen-free evidenced by an absence of Si-H and N-H peaks on an infrared (IR) spectrum.
However, Kagaya teaches a method wherein the deposited silicon nitride is substantially hydrogen-free (par. 0082) evidenced by an absence of Si-H and N-H peaks on an infrared (IR) spectrum (par. 0075).
It would have been obvious to one of ordinary skill in the art at the time the invention was filed to modify Hausmann with Kagaya by providing a hydrogen-free silicon nitride deposit demonstrated with infrared spectroscopy in order to prevent electrical defects, mechanical instability, and elevated etch rates, and infrared spectroscopy is capable of identifying the appropriate frequencies.
Claims 9, 12, and 18 are rejected under 35 U.S.C. 103 as being unpatentable over Hausmann in view of Blanquart et al. (2022/0122841, hereafter Blanquart).
Regarding claim 9, Hausmann, discussed above, fails to disclose a method further comprising repeating steps (a)-(b) to perform at least 100 deposition cycles.
However, Blanquart teaches a method further comprising repeating steps (a)-(b) to perform at least 100 deposition cycles (par. 0112).
It would have been obvious to one of ordinary skill in the art at the time the invention was filed to modify Hausmann with Blanquart by repeating deposition for at least 100 cycles in order to ensures the film overcomes initial nucleation to form continuous, hole-free layer while achieving target thickness.
Regarding claim 12, Hausmann discloses a method further comprising repeating steps (a)-(b) to form a completed silicon nitride layer (par. 0058); and annealing the completed silicon nitride layer in an absence of plasma (par. 0050) wherein the annealing reduces absolute value of stress of silicon nitride (par. 0052).
Hausmann fails to disclose exposing the semiconductor substrate to N2 at a temperature of at least 700.
However, Blanquart teaches exposing the semiconductor substrate to N2 at a temperature of at least 700 degrees C (par. 0127).
It would have been obvious to one of ordinary skill in the art at the time the invention was filed to modify Hausmann with Blanquart by exposing the substrate to nitrogen gas at a temperature of at least 700 degrees C in order to drive out trace hydrogen and increase density of layers.
Regarding claim 18, Hausmann fails to disclose an apparatus wherein the program instructions comprise instructions configured to repeat steps (i) - (ii) to perform at least 100 deposition cycles.
However, Blanquart teaches an apparatus wherein the program instructions comprise instructions configured to repeat steps (i) - (ii) to perform at least 100 deposition cycles (par. 0112).
It would have been obvious to one of ordinary skill in the art at the time the invention was filed to modify Hausmann with Blanquart by repeating deposition cycles at least 100 times in order to ensures the film overcomes initial nucleation to form continuous, hole-free layer while achieving target thickness.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to CHARLES M BRECHT whose telephone number is (571)272-9634. The examiner can normally be reached Mon-Fri: 7:30am - 5pm.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Marlon Fletcher can be reached at (572) 272-2063. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/C.M.B./Examiner, Art Unit 2817
/MARLON T FLETCHER/Supervisory Primary Examiner, Art Unit 2817
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