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 § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 1-10 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 1 recites both “plasma” and “remote plasma” at line 3. It’s unclear if they are the same plasma or different plasma. If they are the same, it’s highly recommended that the same term is used throughout the claims to avoid confusion.
Claim 1 recites “(b) after operation of the remote plasma system reaches a stable state, turning on a radio-frequency power supply system” at lines 5-6. The metes and bounds of “stable state” are unclear, as the term is not defined by the specification. The specification does not explain what is a stable state and what is not a stable state regarding the remote plasma system’s operation. In particular, it’s unclear which parameter(s)—e.g., voltage, current, power, pressure, temperature, flowrate, gas ratio, etc.—and which criteria are used to determine the recited “stable state.” Although ¶ 0074 of the specification discloses that it may take 5-150 seconds for the remote plasma system to reach the stable state, the distinction between “stable” and “not stable” are not explained. Clarification is requested.
Claim 2 recites “the plasma” at line 8. It’s unclear which “plasma” from Claim 1 line 3 is being called “the” plasma. Clarification is requested.
Claim 4 recites two instances of “ratio”:
“a certain ratio of the cleaning gas to the purge gas” and
“the ratio of the flow rate of the cleaning gas to a flow rate of the purge gas.”
It’s unclear if they are the same ratio or different ratios, because the first “ratio” does not recite anything about flow rates, whereas the second “ratio” does. If they are the same ratio, then the claim language must be consistent. Clarification is requested.
For examination purpose, they are interpreted as the same ratio.
Claim 7 recites “wherein in the step (b), when the remote plasma system is turned on for 5-150 seconds and the operation state of the remote plasma system is stable, the radio-frequency power supply system is turned on.” First, the metes and bounds of “stable” and “stable state” are unclear, as explained above. Second, it’s unclear whether the phrase “the remote plasma system is turned on for 5-150 seconds” and the phrase “the operation state of the remote plasma system is stable” are the same requirement, or two separate and distinct requirements. For example, if the remote plasma system is turned on for 5-150 seconds, does the remote plasma system automatically reach stable operation state? If the answer is no, then how can one determine whether or not the remote plasma system has reached stable operation state?
Claim 7 recites “the operation state” at line 2. There is insufficient antecedent basis for this limitation in the claim.
Claim 8 recites “discharge spacing range” at line 5. It’s unclear what’s meant by this term, which is not defined by the specification. In particular, the specification does not explain what is a “discharge spacing” (i.e., spacing between what and what?).
Claim 9 recites “the purge gas” at line 4. There is insufficient antecedent basis for this limitation in the claim.
The remaining claims are rejected because they depend on Claim 1.
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.
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, 8, and 10 are rejected under 35 U.S.C. 103 as being unpatentable over FOX et al. (US PGPUB 20180305814) and JOHNSON et al. (US PGPUB 20060027249).
Regarding Claim 1, FOX teaches a method for cleaning a process chamber (see abstract, Fig. 1-3, ¶¶ 0005-12, 0033-36, cleaning process chamber 102). FOX teaches a remote plasma system (RPS 138, see Fig. 1, ¶¶ 0026-27) and a radio-frequency power supply system (RF generating system 120, see Fig. 1, ¶ 0025).
Hereinafter, “RPS” is shorthand for “remote plasma source” or “remote plasma system,” and “RF” is shorthand for “radio frequency.”
FOX’s method comprises: (a) introducing a clean-process gas into a RPS (see ¶ 0036, NF3 gas supplied to RPS 138), turning on the RPS (see Fig. 3), exciting the gas into plasma (see ¶¶ 0026-27, 0036), and supplying remote plasma to the process chamber (see ¶ 0036).
FOX’s method comprises: (b) after operation of the RPS has started (see abstract, ¶¶ 0005, 0028 0036-38, Figs. 2-3), turning on a RF power supply system (see Figs. 2-3, ¶¶ 0025, 0036, 0038, claims 9-11, using RF generating system 120) in the process chamber (see Fig. 1, ¶ 0025, RF power is supplied to one of electrodes inside process chamber 102). Because RF power is supplied to the electrode inside process chamber 102 while remote plasma is being supplied to the chamber (see abstract, Figs. 2-3, ¶¶ 0005, 0036-38), this means or reasonably suggests that the remote plasma in the process chamber would be re-excited and enhanced by the RF power supply system (see id., using RF power to generate plasma inside the chamber), and the process chamber would be cleaned by utilizing the re-excited and enhanced plasma (see abstract, Figs. 2-4, ¶¶ 0005, 0028, 0036-38, cleaning the chamber using both remote plasma and in-situ plasma).
FOX’s method comprises: using both the RPS 138 and the RF power supply system 120 for jointly acting and cleaning the process chamber 102 during a period of cleaning time (see Figs. 2-5, abstract, ¶¶ 0005, 0021, 0028, 0036-39).
FOX’s method comprises: (c) when the cleaning of the process chamber is completed, firstly turning off the RF power supply system in the process chamber (see Figs. 2-3, ¶¶ 0028, 0036-37, in-situ plasma is extinguished first).
FOX’s method comprises: (d) after the RF power supply system is turned off, turning off the RPS (see Figs. 2-3, ¶¶ 0028, 0036-37, RPS is stopped after extinguishing in-situ plasma).
FOX does not explicitly teach that, in step (b), the RF power supply system 120 is turned on after operation of the RPS 138 “reaches a stable state.”
JOHNSON teaches a chamber-cleaning method that uses both remote plasma and in-situ plasma (see, e.g., ¶¶ 0048, 0057, 0100-09), wherein a RF power supply system is turned on (to start in-situ plasma) after operation of the RPS reaches a stable state (see ¶¶ 0074, 0101, 0105); this can ensure plasma stability, good cleaning results, and negligible damage to the process chamber (see ¶¶ 0045, 0102, 0108).
Before the effective filing date of the claimed invention, it would’ve been obvious to a person having ordinary skill in the art to modify FOX’s method to turn on FOX’s RF power supply system 120 after operation of FOX’s RPS 138 “reaches a stable state,” with reasonable expectation of cleaning the chamber, for several reasons.
First, given the benefits of plasma stability, good cleaning results, and negligible damage to the process chamber, a person of ordinary skill in the art would’ve been motivated to turn on the RF power supply system (to start in-situ plasma) after the RPS reaches a stable state.
Second, it’s already known in the prior art to turn on the RF power supply system (to start in-situ plasma) after the RPS reaches a stable state (see JOHNSON). All the claimed elements were known in the prior art, and one skilled in the art could’ve combined them by known methods with no change in their respective functions, and the combination yielded nothing more than predictable results to one of ordinary skill in the art. See KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 415-421 (2007); MPEP § 2143, A.
Regarding Claim 8, the combination of FOX and JOHNSON teaches the method according to claim 1. The combination teaches wherein operation parameters of the RF power supply system comprise:
a frequency of a RF power supply being 13.26 MHz (see FOX at ¶ 0025), which falls within the claimed range of “2 MHz to 100 MHz”; and/or
a power range of the RF power supply being 500 W to 3000 W (see FOX at ¶ 0025), which falls within the claimed range of “500 W to 90,000 W”; and/or
an operation gas pressure during cleaning of the process chamber being 0.5 to 4 Torr (see FOX at ¶¶ 0011, 0034), which falls within the claimed range of “0.01 Torr to 10 Torr.”
Regarding Claim 10, the combination of FOX and JOHNSON teaches the method according to claim 1. The combination teaches the method is applied in vacuum deposition process apparatus (apparatus 100 of FOX, see Fig. 1, ¶ 0022), wherein the vacuum deposition process apparatus comprises chemical vapor deposition apparatus (see FOX at ¶¶ 0003, 0006, 0051) or atomic layer deposition apparatus (see id.).
Claims 1-3, 5, 8, and 10 are rejected under 35 U.S.C. 103 as being unpatentable over JOHNSON et al. (US PGPUB 20060027249), in view of FOX et al. (US PGPUB 20180305814).
Regarding Claim 1, JOHNSON teaches a method for cleaning a process chamber (see ¶¶ 0057-58, 0100-09). JOHNSON teaches a process chamber (see ¶ 0057, a CVD chamber); a remote plasma system (see id., “Astron” brand from MKS Instruments); and a radio-frequency power supply system in the process chamber (see id., RF power connected to a top shower electrode; see also ¶¶ 0101, 0105).
Hereinafter, the term “Astron” or “Astron-ex” is synonymous with RPS (remote plasma source/system). As explained above, “RPS” is shorthand for remote plasma system/source, and “RF” is shorthand for radio frequency.
JOHNSON’s method comprises: (a) introducing a clean-process gas (e.g., NF3 gas, O2 gas, Ar gas) into a RPS (see ¶¶ 0074, 0101, 0105), turning on the RPS (see id.), exciting the gas into plasma (see id.), and supplying remote plasma to the process chamber (see id.).
JOHNSON’s method comprises: (b) after operation of the RPS reaches a stable state (see ¶¶ 0074, 0101, 0105, after remote plasma has stabilized), turning on a RF power supply system in the process chamber (see id., RF power is applied to showerhead electrode), re-exciting and enhancing the remote plasma positioned in the process chamber by the RF power supply system (see ¶ 0048, discussing remote activation of a gas to generate reactive species, and in-situ activation of those reactive species that may have recombined), and cleaning the process chamber by utilizing the re-excited and enhanced plasma (see ¶¶ 0048, 0074, 0101, 0105).
JOHNSON teaches using both the RPS and the RF power supply system for jointly acting and cleaning the process chamber during a period of cleaning time (see ¶¶ 0048, 0074, 0100-09).
JOHNSON teaches or reasonably suggests: (c) when the cleaning of the process chamber is completed, turning off the RF power supply system in the process chamber; and (d) turning off the RPS, for at least two reasons.
First, JOHNSON teaches turning on the RPS and turning on the RF power supply system for each run of the experiment (see ¶¶ 0074, 0100-01, 0104-05), wherein multiple runs are performed (see ¶¶ 0074, 0100, 0104, Tables II, VI, XII, XIII). This means or suggests that the RPS and the RF power supply system are turned off at the end of each run.
Second, a person of ordinary skill in the art would understand that, after each chamber-cleaning process is completed, the RPS and the RF power supply system are turned off to prevent damage to the process chamber and to save cost/electricity (i.e., those systems are not turned on forever).
JOHNSON does not explicitly teach the order/sequence of turning off the RF power supply system first and then turning off the RPS. But this order/sequence is already known in the prior art.
FOX teaches a method for cleaning a process chamber (see abstract, Fig. 1-3, ¶¶ 0005-12, 0033-36, cleaning process chamber 102) using a RPS (RPS 138, see Fig. 1, ¶¶ 0026-27) and a RF power supply system (RF generating system 120, see Fig. 1, ¶ 0025). FOX teaches (c) when the cleaning of the process chamber is completed, firstly turning off the RF power supply system in the process chamber (see Figs. 2-3, ¶¶ 0028, 0036-37, in-situ plasma is extinguished first); and (d) after the RF power supply system is turned off, turning off the RPS (see Figs. 2-3, ¶¶ 0028, 0036-37, RPS is stopped after extinguishing in-situ plasma).
Before the effective filing date of the claimed invention, it would’ve been obvious to a person having ordinary skill in the art to modify JOHNSON’s method to incorporate the order/ sequence of turning off JOHNSON’s RF power supply system first and then turning off JOHNSON’s RPS, with reasonable expectation of cleaning the chamber. It’s already known in the prior art to turn off the RF power supply system first and then turn off the RPS (see FOX). All the claimed elements were known in the prior art, and one skilled in the art could’ve combined the elements as claimed by known methods with no change in their respective functions, and the combination yielded nothing more than predictable results to one of ordinary skill in the art. See KSR, 550 U.S. at 415-421; MPEP § 2143, A.
Regarding Claim 2, JOHNSON and FOX teaches the method according to claim 1.
The combination teaches wherein the clean-process gas comprises purge gas (Ar gas, see JOHNSON at ¶¶ 0074, 0101, 0105) and cleaning gas (NF3 gas or O2 gas, see id.).
The combination teaches the step (a) comprises:
(a1) pre-treating an inner chamber of the RPS and the process chamber, the pre-treatment comprising purging the inner chamber of the RPS and the process chamber by utilizing the purge gas (see JOHNSON at ¶¶ 0074, 0101, 0105, Ar gas is introduced to the RPS/Astron and the process chamber), and then turning on the RPS (see id. at ¶¶ 0074, 0101, 0105);
(a2) after the RPS is turned on, introducing the cleaning gas (see JOHNSON at ¶¶ 0074, 0101, 0105, after RPS/Astron turned on, introduce either NF3 gas or NF3-O2 gas mixture to generate remote plasma), and supplying the plasma generated by excitation of the RPS to the process chamber (see id., chamber is cleaned with both remote and in-situ plasma).
Although JOHNSON does not explicitly teach that there is a “gas line” between the RPS and the process chamber, such gas line is reasonably expected because JOHNSON teaches that the process chamber is retrofitted with the Astron-brand RPS (see JOHNSON at ¶ 0057), wherein plasma generated in the Astron/RPS is then supplied to the process chamber (see JOHNSON at ¶¶ 0074, 0101, 0105).
Thus, because JOHNSON teaches supplying Ar gas to the Astron/RPS and the process chamber (as explained above), this means step (a1) comprises pre-treating the gas line by purging the gas line with the purge gas.
Alternatively, if a “gas line” is not clearly envisaged by JOHNSON’s teachings, it still would’ve been obvious to incorporate a gas line between JOHNSON’s RPS and JOHNSON’s process chamber, with reasonable expectation of supplying plasma from the Astron/RPS to the process chamber. It’s well known in the art for a deposition apparatus to comprise a gas line connecting between the RPS and the process chamber (see FOX at Fig. 1). All the claimed elements were known in the prior art, and one skilled in the art could’ve combined the elements by known methods with no change in their respective functions, and the combination yielded nothing more than predictable results to one of ordinary skill in the art. See KSR, 550 U.S. at 415-421; MPEP § 2143, A.
In the resulting combination: because JOHNSON teaches supplying Ar gas to the Astron/RPS and the process chamber (as explained above), this means step (a1) comprises pre-treating the gas line by purging the gas line with purge gas.
Regarding Claim 3, JOHNSON and FOX teaches the method according to claim 2. The combination teaches wherein the purge gas comprises at least one of Ar, He, N2, or H2 (see JOHNSON at ¶¶ 0074, 0101, 0105; see also JOHNSON at ¶¶ 0040, additive gas can be argon, helium, nitrogen, hydrogen, and mixtures thereof).
Regarding Claim 5, JOHNSON and FOX teaches the method according to claim 2. The combination teaches wherein the cleaning gas comprises a corrosive gas, the corrosive gas comprises at least one of NF3, CF4, SF6, C2F6, F2, C3F8, CHF3, or HF (see JOHNSON at ¶¶ 0074, 0101, 0105; see also JOHNSON at ¶¶ 0008, 0038).
Regarding Claim 8, JOHNSON and FOX teaches the method according to claim 2. The combination teaches operation parameters of the RF power supply system comprise:
a frequency of a RF power supply being 13.56 MHz (see JOHNSON at ¶¶ 0045, 0055, 0057), which falls within the claimed range of “2 MHz to 100 MHz”; and/or
a power of the RF power supply being 1000W (see JOHNSON at ¶ 0074), 750-1750W (see id. at ¶ 0100), or 1250W (see id. at ¶ 0104), all of which falls within the claimed range of “500 W to 90,000 W”; and/or
an operation gas pressure during cleaning of the process chamber being 2.5 torr (see JOHNSON at ¶ 0074), 1.75-2.50 torr (see id. at ¶ 0100), or 2.0 torr (see id. at ¶ 0104), all of which fall within the claimed range of “0.01 Torr to 10 Torr.”
Regarding Claim 10, the combination of JOHNSON and FOX teaches the method according to claim 1. The combination teaches the method is applied in vacuum deposition process apparatus, wherein the vacuum deposition process apparatus comprises chemical vapor deposition apparatus (see JOHNSON at ¶¶ 0035, 0057, claim 20) or atomic layer deposition apparatus (see id. at ¶ 0035, claim 20).
Claim 4 is rejected under 35 U.S.C. 103 as being unpatentable over the combination of JOHNSON and FOX (as applied to Claim 2 above), in further view of CHANDRAN et al. (US PGPUB 20050103266).
Regarding Claim 4, the combination of JOHNSON and FOX teaches the method according to claim 2. As explained above, the combination teaches that, before the RF power supply system in the process chamber is turned on in step (b), a clean-process gas—which comprises a purge gas (e.g., Ar gas) and a cleaning gas (e.g., NF3 gas)—is introduced into the RPS to generate remote plasma (see JOHNSON at ¶¶ 0074, 0101, 0105). Because the purge gas and the cleaning gas are introduced into the RPS, each gas inherently has a flow rate and there is inherently a ratio of the cleaning gas to the purge gas.
The combination does not explicitly teach: “a flow rate of the cleaning gas in the clean-process gas is gradually increased so as to achieve a certain ratio of the cleaning gas to the purge gas, wherein the ratio of the flow rate of the cleaning gas to a flow rate of the purge gas is gradually increased or stepwise increased.”
CHANDRA teaches a chamber cleaning method using remote plasma (see Figs. 3-4, ¶¶ 0055-56, abstract). CHANDRA teaches introducing a clean-process gas—which comprises both a purge gas (e.g., Ar gas) and a cleaning gas (e.g., NF3 gas) (see Fig. 2, ¶ 0052)—into a remote plasma system (RPS 300, see ¶ 0052) to generate said remote plasma.
CHANDRA teaches that a flow rate of the cleaning gas in the clean-process gas is gradually increased (see abstract, ¶¶ 0010-12, 0054-55, slowly accelerating the flow of fluorine source gas) so as to achieve a certain ratio of the cleaning gas to the purge gas (see abstract, ¶¶ 0010-12, 0054, 0056, 0059), wherein the ratio of the flow rate of the cleaning gas to a flow rate of the purge gas is gradually increased (see Fig. 3, ¶¶ 0055, the ratio is initially 1.67 to 13.33 scc/s, or approximately 1:8, and the ratio is increased to 8.33 to 13.33 scc/s, or approximately 1:1.6; see also ¶¶ 0011, 0054, target ratio is about 3:2).
By gradually increasing the flow rate of the cleaning gas to increase the ratio of cleaning gas to purge gas, it’s possible to avoid quenching the plasma in the RPS (see ¶¶ 0010, 0054).
Before the effective filing date of the claimed invention, it would’ve been obvious to a person having ordinary skill in the art to modify the combination of JOHNSON and FOX to incorporate “a flow rate of the cleaning gas in the clean-process gas is gradually increased so as to achieve a certain ratio of the cleaning gas to the purge gas, wherein the ratio of the flow rate of the cleaning gas to a flow rate of the purge gas is gradually increased,” with reasonable expectation of generating the remote plasma, for several reasons.
First, given the benefit of avoiding the plasma being quenched in the RPS, a person of ordinary skill in the art would’ve been motivated to gradually increase the flow rate of the cleaning gas to achieve a certain ratio of the cleaning gas to the purge gas, wherein said ratio is also gradually increased.
Second, it’s already known in the art to gradually increase the flow rate of the cleaning gas to achieve a certain ratio of the cleaning gas to the purge gas, wherein said ratio is also gradually increased (see CHANDRA). All the claimed elements were known in the prior art, and one skilled in the art could’ve combined the elements by known methods with no change in their respective functions, and the combination yielded nothing more than predictable results to one of ordinary skill in the art. See KSR, 550 U.S. at 415-421; MPEP § 2143, A.
Claim 6 is rejected under 35 U.S.C. 103 as being unpatentable over the combination of JOHNSON and FOX (as applied to Claim 1), in view of TANG et al. (US PGPUB 20140091417) and Wikipedia.org (“Artificial plasmas” and “Radio frequency”).
Regarding Claim 6, the combination of JOHNSON and FOX teaches the method according to claim 1. The combination teaches that the RPS belongs to the “Astron” brand from MKS Instruments (see JOHNSON at ¶ 0057, using the “Astron-ex” model). Because the “Astron-ex” RPS is turned on (as explained above), it inherently has a power supply.
The combination does not explicitly teach: “the remote plasma system comprises an inductive coil coupled discharge structure, and the remote plasma system adopts an alternating-current power supply having a frequency of 100 KHz to 13.56 MHz.”
But the “Astron-ex” RPS is known to comprise an inductive coil coupled discharge structure (see TANG at ¶¶ 0044, 0066). In other words, for the “Astron-ex” RPS disclosed in JOHNSON’s method, the inductive coil coupled discharge structure is either inherently present or reasonably expected to be present.
Moreover, the “Astron-ex” RPS is known to adopt a RF power supply having a frequency of about 2 KHz to 15 MHz (see TANG at ¶ 0044), which overlaps with the claimed range of “100 KHz to 13.56 MHz.” Given the overlap, the claimed range is considered obvious (see MPEP § 2144.05.I.).
Additionally, a person of ordinary skill in the art would understand that the RF power supply in the “Astron-ex” RPS is an alternating-current (AC) power supply. See “Plasma (physics)—artificial plasmas,” Wikipedia.org, archived by Wayback Machine on July 18, 2020, available at https://web.archive.org/web/20200718193547/https://en.wikipedia.org/wiki/ Plasma_(physics)#Artificial_plasmas (treating RF and AC as synonymous or interchangeable); see also “radio frequency”, Wikipedia.org, archived by Wayback Machine on April 26, 2020, available at https://web.archive.org/web/20200426223934/https://en.wikipedia.org/wiki/ Radio_frequency (RF refers to the oscillation rate of alternating electric current).
Claims 7 and 9 are rejected under 35 U.S.C. 103 as being unpatentable over the combination of JOHNSON and FOX (as applied to Claim 1 above), in further view of “Application Note: Astron Remote Plasma Source Ignition Best Practices” published by MKS Instruments in August 2022 (hereinafter “MKS” or “MKS Note”).
Regarding Claim 7, the combination of JOHNSON and FOX teaches the method according to claim 1. As explained above, the combination teaches that, in (b), after operation of the RPS reaches a stable state, turning on the RF power supply system (see JOHNSON at ¶¶ 0074, 0101, 0105), wherein the RPS belongs to the “Astron” brand manufactured by MKS Instruments (see id. at ¶ 0057).
The combination does not explicitly teach that the RF power supply system is turned on “when the remote plasma system is turned on for 5-150 seconds.”
MKS Instruments published a note called “Astron Remote Plasma Source Ignition Best Practices” (Aug. 2022), available at https://api.p1.mks.com/medias/sys_master/resources/he3/ h30/9954640232478/ASTRON-BestPractices-AppNote/ASTRON-BestPractices-AppNote.pdf. The MKS Note discloses that, after the RPS is turned on, it typically takes 5-45 seconds to reach a stable state (see pg. 5, durations for Ignition and Transition 1). The disclosed range of 5-45 seconds overlap with the claimed range of 5-150 seconds; given this overlap, the claimed range is considered obvious (see MPEP § 2144.05.I.).
In the resulting combination: the RF power supply system is turned on after operation of the RPS reaches a stable state (see JOHNSON), which typically takes 5-45 seconds from the turning-on of the RPS (see MKS Note). In other words, the RF power supply system is turned on when the remote plasma system is turned on for 5-45 seconds and the operation state of the remote plasma system is stable.
Regarding Claim 9, the combination of JOHNSON and FOX teaches the method according to claim 1. As explained above, the combination teaches that, when the chamber cleaning is completed, the RF power supply system is turned off first, and then the RPS is turned off (see FOX at Figs. 2-3, ¶¶ 0028, 0036-37).
The combination does not explicitly: “after the radio-frequency power supply system is turned off and before the remote plasma system is turned off, only introducing the purge gas, exciting the purge gas by utilizing the remote plasma system to generate plasma, and purging the process chamber by utilizing the plasma.”
The MKS Note discloses that, after completing the chamber clean, it’s ideal to keep the RPS still activated while transitioning back to argon gas to run argon plasma for a several seconds (see item 3 on pg. 4, see table in pg. 5). In other words, the MKS Note teaches: after completing the chamber clean and before the RPS is turned off, only introducing the purge gas (e.g., Ar gas), exciting the purge gas by utilizing the RPS to generate plasma, and purging the process chamber by utilizing the plasma. This argon plasma helps remove residues left by the cleaning gas to avoid impeding the next ignition of the RPS (see pg. 4).
Before the effective filing date of the claimed invention, it would’ve been obvious to a person having ordinary skill in the art to modify the combination of JOHNSON and FOX to incorporate the following steps: after completing the chamber clean and before the RPS is turned off, only introducing the purge gas (e.g., Ar gas), exciting the purge gas by utilizing the RPS to generate plasma, and purging the process chamber by utilizing the plasma, with reasonable expectation of removing residues.
First, given the benefits of removing residues left by the cleaning gas to avoid impeding the next ignition of the RPS, a person of ordinary skill in the art would’ve been motivated to keep the RPS still activated and run an argon plasma, after the chamber clean is completed.
Second, it’s already known in the prior art to keep the RPS still activated and run an argon plasma, after the chamber clean is completed (see MKS Note). All the claimed elements were known in the prior art, and one skilled in the art could’ve combined the elements as claimed by known methods with no change in their respective functions, and the combination yielded nothing more than predictable results to one of ordinary skill in the art. See KSR, 550 U.S. at 415-421; MPEP § 2143, A.
In the resulting combination of JOHNSON, FOX, and the MKS Note: after completing the chamber clean, the RF power supply system is turned off first, but the RPS is still activated (i.e., before the RPS is turned off) to generate an argon plasma to clean residues, i.e., only introducing the purge gas (e.g., Ar gas), exciting the purge gas by utilizing the RPS to generate plasma, and purging the process chamber by utilizing the plasma.
Relevant Prior Art
The following prior art—made of record and not relied upon—are considered pertinent to applicant's disclosure:
SAWIN et al. (US PGPUB 20070028943) teaches generating a remote plasma using an Astron-brand RPS by MKS Instruments (see ¶ 0027, the “Astron-ex” is a toroidal-type RPS), wherein such RPS comprises an inductively coupled discharge structure (see ¶ 0018, the toroidal-type RPS is inductively coupled).
ASHIGAKI et al. (WIPO Publication WO2006121117A1, as translated by Espacenet) discloses that an Astron-brand RPS (by MKS) that generates plasma using an inductive coupling plasma (ICP) method (¶ 0027).
MILLS (US PGPUB 20100209311) discloses that the Astron-brand RPS (by MKS) comprises an inductively coupled plasma source (¶¶ 0100, 0107), wherein the RPS is driven by a RF power supply at about 1 kHz to 100 MHz, preferably around 13.56 MHz (see id.).
MILLS (US PGPUB 20060233699) discloses that the Astron-brand RPS (by MKS) comprises an inductively coupled plasma source (¶¶ 0101, 0109), wherein the RPS is driven by a RF power supply at about 1 kHz to 100 MHz, preferably around 13.56 MHz (see id.).
ARGHAVANI et al. (US PGPUB 20140308812) discloses that the Astron-brand RPS (by MKS) comprises an inductively coupled source (¶ 0070).
CHEN et al. (US PGPUB 20140030889) discloses that the Astron-brand RPS (by MKS) comprises an inductively coupled source (¶ 0069).
HAVERKAMP et al. (US PGPUB 20140094038) discloses that the Astron-brand RPS (by MKS) comprises an inductively coupled source (¶ 0052).
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to RICHARD ZHANG whose telephone number is (571)272-3422. The examiner can normally be reached M-F 09:00-17:00 Eastern.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, KAJ OLSEN can be reached at (571) 272-1344. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/R.Z.Z./Examiner, Art Unit 1714
/KAJ K OLSEN/Supervisory Patent Examiner, Art Unit 1714
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