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 .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicants’ submission filed on July 24, 2026, has been entered.
Specification
The objection to the title is withdrawn in view of applicants’ submission of a replacement title.
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 1, 4, and 8 is/are rejected under 35 U.S.C. 103 as being unpatentable over Korean Patent Appl. Publ. No. KR 10-2018-0011428 to Park, et al. (hereinafter “Park”) in view of U.S. Patent Appl. Publ. No. 2002/0153349 to Okumura, et al. (“Okumura”) and further in view of U.S. Patent Appl. Publ. No. 2003/0045075 to Joo, et al. (“Joo”).
Regarding claim 1, Park teaches a method for selectively forming a thin film on a semiconductor substrate by injecting a first cleaning gas, a process gas, and a second cleaning gas in a chamber (see the Abstract, Figs. 1-10, and entire reference which teach a method of processing a wafer (W) in at least steps (S85), (S87), and (S89)) comprising:
a preparation process of seating a substrate on a support in a chamber (see Figs. 7-8 and associated descriptive text in pp. 6-10 of the English translation which teach that a wafer (W) is provided on a substrate support (152) in a chamber (151));
a first cleaning process, including a first process and a second process, the first process including injecting a first cleaning gas containing SF6 into the chamber and removing a native oxide on the substrate (see Figs. 7-8 and pp. 7-10 which teach using plasma etching to remove an oxide layer from the substrate (W) surface in step (S85) using a fluorine-containing gas such as SF6);
the second process including removing by-products containing fluorine (F) decomposed form the first cleaning gas by injecting a second cleaning gas into the chamber after the first process is completed, wherein the by-products containing fluorine (F) are generated in the first process, wherein the second cleaning gas is different from the first cleaning gas, wherein the second process is performed after removing the native oxide by the first process is completed (see Figs. 7-8 and pp. 7-10 which teach that after the oxide layer is removed in step (S85) using SF6, the surface layer of the etched portion is removed using a halogen-based gas such as Cl2 in step (S87); moreover, the introduction of Cl2 in step (S87) will necessarily remove at least some by-products containing F produced in step (S85));
a growth process of injecting a process gas into the chamber after the first cleaning process removes the by-products and growing a thin film on a growth area on one surface of the substrate (see Figs. 7-8 and pp. 7-10 which teach the growth of an epitaxial Si or SiGe layer onto the substrate (W) using a Si source gas such as silane (SiH4) in step (S89) which is performed after the first cleaning process in step (S85)); and
a process of generating a plasma in the chamber in the first cleaning process (see Figs. 7-8 and pp. 7-10 which teach the use of plasma etching during the first cleaning process in which the oxide layer is removed in step (S85)),
wherein an inner temperature of the chamber is in a range from 300°C to 750°C during the first cleaning process (see Figs. 7-8, pp. 7-10, and claims 7 & 9 which teach that the substrate is heated to the overlapping temperature of 500 °C or more and 800 °C or less during the deposition process and that the internal temperature may be adjusted as needed; accordingly it would have been within the capabilities of a PHOSITA prior to the effective filing date of the invention to utilize routine experimentation to determine an optimal substrate temperature within the overlapping range of 500 to 800 °C that leads to more efficient removal of the oxide layer in step (S85) and the etching process in step (S87)).
Park does not explicitly teach that the plasma is an inductively coupled plasma (ICP) or that an ICP is used during the second process of removing by-products containing fluorine. However, in Figs. 1-3 and ¶¶[0082]-[0095] as well as elsewhere throughout the entire reference Okumura teaches an analogous embodiment of a plasma etching system and method which utilizes an induction coil (6) to generate a plasma within a vacuum chamber (1) in order to etch the surface of a substrate (8). In ¶[0093] Okumura specifically teaches the use of an ICP to etch a silicon oxide film on the substrate while ¶[0086] teaches the use of an ICP to produce a plasma using Cl2 gas in order to etch the surface of a thin film. Thus, a person of ordinary skill in the art prior to the effective filing date of the invention would look to the teachings of Okumura and would recognize that the plasma utilized during the oxide removal step (S85) in the method of Park may be in the form of an ICP since this would involve nothing more than the use of a known method of producing a plasma according to its intended use. Moreover, since the ICP system of Okumura has the advantage of minimizing the formation of spurious deposits within the chamber such as on the dielectric plate, a PHOSITA prior to the effective filing date of the invention would be motivated to utilize an ICP during the etching process in step (S87) in the method of Park in order to improve the etching efficiency and minimize the formation of additional spurious deposits within the chamber.
Park and Okumura do not teach a second cleaning process of injecting the second cleaning gas into the chamber after the growth process to remove impurities remaining on the one surface of the substrate. However, in Figs. 5-6 and ¶¶[0024]-[0031] as well as elsewhere throughout the entire reference Joo teaches an analogous method of promoting selective epitaxial growth on a substrate that has predefined regions that are covered and exposed using a mask layer. Epitaxial growth initially proceeds using a Si- or Ge-containing precursor in a second step which is followed by a third step in which Cl2 gas is introduced to remove spurious deposits that may form on the epitaxial growth surface as well as the masked regions. The second and third steps are then repeated until the epitaxial layer is grown to a desired thickness. Thus, a person of ordinary skill in the art prior to the effective filing date of the invention would look to the teachings of Joo and would be motivated to repeat the second cleaning process of Park such that Cl2 is introduced into the chamber after the growth process in order to remove the formation of spurious deposits and any remaining impurities until the desired film thickness is reached. The combination of prior art elements according to known methods to yield predictable results has been held to support a prima facie determination of obviousness. All the claimed elements are known in the prior art and one skilled in the art could combine the elements as claimed by known methods with no change in their respective functions, with the combination yielding nothing more than predictable results to one of ordinary skill in the art. KSR International Co. v. Teleflex Inc., 550 U.S. 398, __, 82 USPQ2d 1385, 1395 (2007). See also, MPEP 2143(A).
Regarding claim 4, Park does not explicitly teach that the second cleaning process comprises a process of generating inductively coupled plasma (ICP) in the chamber. However, as noted supra with respect to the rejection of claim 1, in Figs. 1-3 and ¶¶[0082]-[0095] as well as elsewhere throughout the entire reference Okumura teaches an analogous embodiment of a plasma etching system and method which utilizes an induction coil (6) to generate a plasma within a vacuum chamber (1) in order to etch the surface of a substrate (8). In ¶[0093] Okumura specifically teaches the use of an ICP to etch a silicon oxide film on the substrate. Moreover, the ICP system of Okumura has the advantage of minimizing the formation of spurious deposits within the chamber such as on the dielectric plate. Thus, a person of ordinary skill in the art prior to the effective filing date of the invention would look to the teachings of Okumura and would be motivated to utilize an ICP as part of the second cleaning step (S87) in order to improve the etching efficiency and further minimize the formation of spurious deposits within the chamber during the etching process.
Regarding claim 8, Park and Okumura do not teach that the growth process and the second cleaning process are alternately performed a plurality of times. However, in Figs. 5-6 and ¶¶[0024]-[0031] as well as elsewhere throughout the entire reference Joo teaches an analogous method of promoting selective epitaxial growth on a substrate that has predefined regions that are covered and exposed using a mask layer. Epitaxial growth initially proceeds using a Si- or Ge-containing precursor in a second step which is followed by a third step in which Cl2 gas is introduced to remove spurious deposits that may form on the epitaxial growth surface as well as the masked regions. The second and third steps are then repeated until the epitaxial layer is grown to a desired thickness. Thus, a person of ordinary skill in the art prior to the effective filing date of the invention would look to the teachings of Joo and would be motivated to alternatively perform the growth and second cleaning process of Park a plurality of times in order to periodically remove the formation of spurious deposits until the desired film thickness is reached.
Claims 5-7 is/are rejected under 35 U.S.C. 103 as being unpatentable over Park in view of Okumura and further in view of Joo and still further in view of U.S. Patent No. 5,356,478 to Chen, et al. (“Chen”).
Regarding claim 5, Park, Okumura, and Joo do not teach a chamber cleaning process that is performed in at least one of before the substrate is loaded into the chamber and after the substrate in the chamber is withdrawn to the outside, wherein the chamber cleaning process comprises a process of injecting the second cleaning gas into the chamber. However, in col. 1, ll. 23-51 Chen teaches that conventional processing of semiconductor wafers leads to a build-up in residue on surfaces inside the plasma treatment chamber which deteriorates the performance of subsequent processes and leads to potential cross-contamination issues. In col. 3, l. 42 to col. 2, l. 60 as well as the Example at col. 4, l. 65 to col. 5, l. 45 Chen specifically teaches that residual contaminants may be efficiently removed from interior surfaces of a plasma treatment chamber using a plasma formed from chlorine (Cl2) and oxygen (O2) gases. Thus, a person of ordinary skill in the art prior to the effective filing date of the invention would be motivated to perform a plasma cleaning process before or after the substrate is loaded into the chamber using the same Cl2 gas that was used in the second cleaning process of Park in order to remove residue that builds up on interior surfaces of the chamber and have that same residue removed through the exhaust without being redeposited onto a device wafer.
Regarding claim 6, Park and Chen do not teach that the chamber cleaning process comprises a process of generating inductively coupled plasma (ICP) in the chamber. However, as noted supra with respect to the rejection of claim 1, in Figs. 1-3 and ¶¶[0082]-[0095] as well as elsewhere throughout the entire reference Okumura teaches an analogous embodiment of a plasma etching system and method which utilizes an induction coil (6) to generate a plasma within a vacuum chamber (1) in order to etch the surface of a substrate (8) which also necessarily etches interior surfaces of the chamber itself. In ¶[0007], ¶[0019], and ¶[0086] Okumura specifically teaches the use of an ICP with Cl2 as a process gas to effectively etch various different metals such as iridium. Thus, a person of ordinary skill in the art prior to the effective filing date of the invention would look to the teachings of Okumura and would recognize that the plasma utilized for chamber cleaning in the method of Chen may be in the form of an ICP since this would involve nothing more than the use of a known method of producing a plasma according to its intended use. Moreover, the ICP system of Okumura has the advantage of minimizing the formation of spurious deposits which re-deposit on chamber walls. Consequently, a person of ordinary skill in the art prior to the effective filing date of the invention would be motivated to utilize an ICP in order to improve the etching efficiency and minimize the formation of spurious deposits which re-deposit on chamber walls.
Regarding claim 7, Park teaches applying power to a plasma generation unit outside the chamber in order to generate the plasma in the chamber (see Fig. 8 and pp. 8-10 which teach the use of voltage sources (215a) and (215b) to apply power to generate a plasma (P) within the chamber), but does not teach that the RF power used to generate the inductively coupled plasma (ICP) in the chamber cleaning process is different from that of a RF power applied in the first and second cleaning processes. However, in at least ¶¶[0007]-[0008], ¶[0014], ¶[0060], and ¶¶[0082]-[0087] as well as elsewhere throughout the entire reference Okumura teaches the use of an ICP to produce a plasma and etch the surface of the substrate (8) as well interior walls of the chamber (1). A power supply (4) is used to apply a high-frequency power of between 100 kHz to 100 MHz to a coil (6) while a separate power supply (9) is used to apply power to the substrate electrode (7). A different applied power is used to etch an oxide film such as SiO2 compared to a metallic film such as iridium. Moreover, since process parameters such as the plasma size, ion energies, and plasma density are influenced by the RF power it is considered to be a result-effective variable, i.e., a variable which achieves a recognized result. See, e.g., In re Antonie, 559 F.2d 618, 195 USPQ 6 (CCPA 1977). See also MPEP 2144.05(II)(B). It therefore would have been within the capabilities of a person of ordinary skill in the art to utilize routine experimentation to determine the optimal RF power delivered to the ICP during the chamber cleaning process of Chen and the surface etching process of Park in order to more efficiently etch the desired areas within the chamber. Due to the differing locations and sizes of the chamber walls and substrate surface this invariably would involve the use of a different RF power for each etching process.
Response to Arguments
Applicants’ arguments filed July 24, 2026, have been fully considered, but they are not persuasive and are moot in view of the new grounds of rejection set forth in this Office Action.
Applicants argue that Park and Okumura do not teach a second cleaning process of injecting the second cleaning gas into the chamber after the growth process. See applicants’ 7/24/2026 reply, pp. 3-5. Applicants’ argument is noted, but is moot in view of the new grounds of rejection set forth in this Office Action. In this case Joo has been relied upon to teach performing a second cleaning process in which Cl2 gas is introduced after the growth step.
Applicants argue that Park does not recognize the issue of impurities caused by oxide removal using SF6 and does not teach the use of a plasma during step (S87). Id. at pp. 5-6. Applicants’ argument is noted, but it is pointed out that even if Park does not recognize the issue of impurities caused by oxide removal, this is irrelevant as the introduction of Cl2 in step (S87) in the method of Park will also have the effect of removing impurities caused by the oxide removal in step (S85). Moreover, the Examiner has relied upon Okumura to teach that the use of an ICP to produce a plasma during different etching processes is known in the art and that a PHOSITA would be motivated to utilize an ICP during steps (S85) and (S87) in the method of Park in order to improve the etching efficiency and to minimize the formation of spurious deposits.
Finally, applicants argue that Park does not teach that the inner temperature is from 300 to 750 °C during the first cleaning process as the disclosed temperature of 500 to 800 °C is only utilized during the hydrogen bake. Id. at pp. 5 & 7. Applicants’ argument is noted, but it is pointed out that discussions of the temperature in the teachings of Park indicate that the internal temperature may be adjusted to the desired value during each of the hydrogen bake, oxygen layer removal, and surface layer removal process. Accordingly, it is the Examiner’s position that a PHOSITA would start with a temperature of 500 to 800 °C and would utilize routine experimentation to determine the optimal substrate and/or chamber temperature necessary to efficiently etch the substrate in steps (S85) and (S87) in the method of Park.
Applicants argue against the reliance on Okumura, Chen, and Joo by contending that these references fail to disclose a native oxide film removal process prior to the growth process as required by claim 1. Id. at p. 6-7. Applicants’ argument is noted, but is unpersuasive as it amounts to arguing against the references individually. In this case it is Park rather than Okumura, Chen, and Joo that is relied upon to teach the first cleaning process of removing a native oxide on the substrate. One cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986).
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. A publication to S. Ullal, et al. entitled “Maintaining reproducible plasma reactor wall conditions: SF6 plasma cleaning of films deposited on chamber walls during Cl2/O2 plasma etching of Si,” J. Vac. Sci. Technol. A, Vol. 20, pp. 1195-1201 (2002) teaches a method of using a SF6 plasma to clean residue deposited onto chamber walls.
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/KENNETH A BRATLAND JR/Primary Examiner, Art Unit 1714
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