Alan Ritchie et al.Download PDFPatent Trials and Appeals BoardNov 26, 201913798021 - (D) (P.T.A.B. Nov. 26, 2019) Copy Citation UNITED STATES PATENT AND TRADEMARK OFFICE UNITED STATES DEPARTMENT OF COMMERCE United States Patent and Trademark Office Address: COMMISSIONER FOR PATENTS P.O. Box 1450 Alexandria, Virginia 22313-1450 www.uspto.gov APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO. 13/798,021 03/12/2013 ALAN RITCHIE 17107USA 8186 55649 7590 11/26/2019 Moser Taboada / Applied Materials, Inc. 1030 Broad Street Suite 203 Shrewsbury, NJ 07702 EXAMINER BAND, MICHAEL A ART UNIT PAPER NUMBER 1794 NOTIFICATION DATE DELIVERY MODE 11/26/2019 ELECTRONIC Please find below and/or attached an Office communication concerning this application or proceeding. The time period for reply, if any, is set in the attached communication. Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the following e-mail address(es): ataboada@mtiplaw.com docketing@mtiplaw.com llinardakis@mtiplaw.com PTOL-90A (Rev. 04/07) UNITED STATES PATENT AND TRADEMARK OFFICE ________________ BEFORE THE PATENT TRIAL AND APPEAL BOARD ________________ Ex parte ALAN RITCHIE,1 John C. Forster, and Muhammad Rasheed ________________ Appeal 2018-007785 Application 13/798,021 Technology Center 1700 ________________ Before BRADLEY R. GARRIS, MARK NAGUMO, and MICHAEL G. MCMANUS, Administrative Patent Judges. NAGUMO, Administrative Patent Judge. DECISION ON APPEAL Applied Materials, Inc. (“Ritchie”) timely appeals under 35 U.S.C. § 134(a) from the Final Rejection2 of all pending claims 6, 8–14, and 16–20. We have jurisdiction. 35 U.S.C. § 6. We reverse. 1 The applicant under 37 C.F.R. § 1.46 (Application Data Sheet, filed 12 March 2013), and hence the appellant under 35 U.S.C. § 134, is the real party in interest, identified as Applied Materials, Inc. (Appeal Brief, filed 27 March 2018 (“Br.”), 3.) 2 Office Action mailed 8 September 2017 (“Final Rejection”; cited as “FR”). Appeal 2018-007785 Application 13/798,021 2 OPINION A. Introduction3 The subject matter on appeal relates to physical vapor deposition (PVD) processing equipment. (Spec. 1 [0001].) An example of a PVD apparatus 1004 is shown in Figure 1, below. {Figure 1 shows a PVD processing apparatus (annotations added)} 3 Application 13/798,021, Methods and apparatus for reducing sputtering of a grounded shield in a process chamber, filed 12 March 2013. We refer to the “′021 Specification,” which we cite as “Spec.” 4 Throughout this Opinion, for clarity, labels to elements are presented in bold font, regardless of their presentation in the original document. Appeal 2018-007785 Application 13/798,021 3 PVD apparatus 100 comprises chamber body 104 fitted with target 114, which faces substrate 108 held on substrate support 106. (Spec. 5 [0016]–[0017].) Various gases may be supplied to the lower part of chamber body 104 from gas source 126, and exhaust port 130 is used to maintain the desired pressure inside the chamber. (Id. at 6 [0019].) Grounded shield 138 comprises inner wall 143 disposed between target 114 and substrate support 106 (id. at 7 [0022]), surrounding first volume 120, and extending below a top surface of substrate support 106 and returning upwardly, forming a u-shaped portion at the bottom of the shield (id. at 10 [0029]). For the “short throw” process chambers of interest in this appeal, the ratio of the diameter of target 114 to the diameter of substrate 108 is about 1.4, and the ratio of the diameter of the target 114 to the height5 of grounded shield 138 is “about 4.1 to about 4.3.” (Id. at 7 [0022].) RF power source 182 applies RF power to target 114 to eject material to be sputter coated on substrate 108. (Spec. 17 [0051].) The RF power also forms a plasma in first volume 120 at a desired frequency and pressure, which is said to “allow[] for a high deposition rate within the short throw 5 The Specification does not appear to provide a precise definition of the term “height of the grounded shield.” The clearest description reads, “[t]he grounded shield 138 comprises an inner wall 143 disposed between the target 114 and the substrate support 106. The height of the shield 138 depends upon the distance 185 between the target 114 and the substrate 108. The distance 185 between the target 114 and the substrate 108, and correspondingly, the height of the shield 138, is scaled based on the diameter of the substrate 108.” (Spec. 7 [0022].) This passage suggests, but does not require, that the height of the shield corresponds roughly to the distance between the target and the substrate. Appeal 2018-007785 Application 13/798,021 4 process chamber while maintaining high ionization levels.” (Id.) The Specification teaches that short throw process chambers provide higher deposition rates than long throw chambers. (Id. at 7–8 [0023].) According to the ′021 Specification, a “dark space region,” also referred to as a “sheath region,” exists between a plasma and the surrounding surfaces. (Spec. 1 [0002].) As the frequency of the radio frequency (RF) exciting source increases, the plasma density increases and the sheath width decreases. (Id.) The inventors discovered that under certain circumstances, “the plasma potential can be in the region of a few tens to a few hundred volts positive with respect to the grounded shield.” (Id.) In the words of the Specification, “[t]his potential difference coupled with the high plasma-ion density can cause undesirable sputtering of the grounded shield,” leading to contamination of the chamber and the substrate. (Id.) The inventors discovered that the voltage between target 114 (the powered electrode) and grounded shield 138 (the grounded electrode) depends “on the ratio of the surface area of the shield 138 to the surface area of the target 114” (Spec. 8 [0024]), with the smaller electrode having the higher voltage (id.). In the words of the Specification, “[t]ypically, the surface area of the target 114 is larger than the surface area of the shield 138 resulting in a greater voltage upon the shield 138, and in turn, resulting in the undesired sputtering of the shield.” (Id.)6 The inventors discovered further “that a ratio of the surface area of the shield 138 to the surface area 6 Ritchie attempted, with partial success, to correct typographical errors in the original Specification in a series of three amendments during prosecution. Appeal 2018-007785 Application 13/798,021 5 of the target 114 of about 1 to about 1.5 advantageously minimizes or prevents the sputtering of the shield 138.” (Id. at 9 [0024].) The Specification teaches, however, that the increase in area of the shield cannot be obtained simply by increasing the height of the shield, due to the desired ratio of the diameter of target 114 to the height of the shield 138. (Spec. 9 [0025].) Moreover, according to the Specification, the diameter of shield 138 cannot be increased enough to prevent sputtering, due to physical constraints on the size of the processing chamber. (Id.) The solution found by the inventors is to provide shield 138 with “a plurality of waves 202 comprising a concave portion 204 and a concave portion 206.” (Spec. 9 [0026].) According to the Specification, the surface area of shield 138 can be increased “by about 50% while maintaining the same overall height of the shield 138.” (Id.) This arrangement is illustrated in Figure 2, reproduced below. {Figure 2 shows waves on the inner wall of grounded shield 138} The Specification teaches that “[t]he concave portion 204 of the waves 202 are sized to advantageously allow the plasma sheath to form Appeal 2018-007785 Application 13/798,021 6 within the concave portion 204 of each wave 202.” (Spec. 10 [0027].) Thus, the size of the concave portions will depend on the RF frequencies used for processing, and increasing or decreasing the number of waves 202 in shield 138 “allows for the flexibility of controlling the plasma potential (e.g., the voltage on the shield) without changing the distance 185 between the target 114 and the substrate 108.” (Id.) The Specification discloses that for RF frequencies of interest (about 27–162 MHz), “the period of the wave 202 is about 6 mm to about 20 mm.” (Id.) In the words of the Specification, “[t]he inventive apparatus may advantageously allow for an increased deposition rate in a PVD chamber, without the contamination caused by the sputtering of the grounded shield.” (Spec. 17 [0052].) Claim 6 is representative and reads: A substrate processing apparatus [100], comprising: a chamber body [104] having a substrate support [106] disposed therein; a target [114] coupled to the chamber body [104] opposite the substrate support [106]; an RF power source [182] to form a plasma within the chamber body [104]; and a grounded shield [138] having an inner sidewall [143] including a plurality of waves [202] disposed between the target [114] and the substrate support [106]; wherein a ratio of a diameter of the target [114] to a height of the grounded shield [138] is about 4.1 to about 4.3, and wherein a ratio of a surface area of inner facing surfaces of the inner sidewall [143] to a surface area of a Appeal 2018-007785 Application 13/798,021 7 principal surface of the target [114] is about 1 to about 1.5. (Claims App., Br. 9; some formatting, and emphasis added.) Remaining independent claim 14 is similar, but is broader in that the ratio of the target diameter to the height of the grounded shield “is about 4,” and is narrower in that each of the concave portions must allow a plasma sheath to form within the concave portion in a range of specified RF frequencies and chamber pressures. (Claims App., Br. 10.) The Examiner maintains the Final Rejection and enters a new ground of rejection over the same references, based on a new interpretation of the height of the shield7, 8: Claims 6, 8–14, and 16–20 stand rejected under 35 U.S.C. § 103(a) in view of the combined teachings of Sasaki9 and Murugesh.10 7 Examiner’s Answer mailed 22 May 2018 (“Ans.”). 8 Because this application was filed before 16 March 2013, the effective date of the America Invents Act, we refer to the pre-AIA version of the statute. 9 Masao Sasaki and Kiyohiko Funato, Ionizing sputtering method, U.S. Patent No. 6,444,099 B1 (2002). 10 Laxman Murugesh and Abhijit Desai, Chamber component having grooved surface with depressions, U.S. Patent Application Publication 2005/0284372 A1 (2005). Appeal 2018-007785 Application 13/798,021 8 B. Discussion The Board’s findings of fact throughout this Opinion are supported by a preponderance of the evidence of record. The Examiner finds that Sasaki describes a substrate processing apparatus, shown in Figure 1, shown below, that meets many of the limitations of the representative claim. {Sasaki Figure 1 shows an apparatus for ionizing sputtering (annotations added)} However, the Examiner finds that Sasaki does not teach or suggest a grounded shield with waves or the ratio of the diameter of the target to the Appeal 2018-007785 Application 13/798,021 9 height of the grounded shield being about 4.1 to about 4.3, or the ratio of the surface area of the inner facing surfaces of the inner sidewall to the area of the principal surface of the target of 1 to 1.5. (FR, para. bridging 5–6.) Rather, the embodiments described by Sasaki have a ratio of the diameter of the target to a height of the ground shield to be about 6.3, and a ratio of the surface area of the grounded shield to the surface area of a principal surface of the target of about 0.61. (Id. at para. bridging 4–5.) The Examiner finds (FR 3) that Murugesh describes a substrate processing chamber11 illustrated in Figure 3, shown below with annotations {Murugesh Figure 3 shows a substrate processing chamber. The highlighted elements can be textured (grooved) (Murugesh 2 [0018])} indicating which components are suggested for having textured (grooved) surfaces, including a shield 123 (id. (citing Murugesh 2 [0018])) having a 11 The chamber is said to be for processing substrates with an “energized gas.” (Murugesh 2 [0018].) Murugesh discloses sputtering with a plasma. (Id. at 6 [0045].) Appeal 2018-007785 Application 13/798,021 10 height that is extended below the substrate support and covers an entire sidewall of the chamber body to protect the wall from the energized process gas (id. (citing Murugesh 6, [0044]–[0045])). The Examiner finds that Murugesh discloses a “period [r] for each groove [64] is 7 mm.” (Id. (citing Murugesh 5 [0039], referring to Figure 4, not reproduced here.)) The Examiner (FR 3) relies on Murugesh Figures 1B and 5 (not reproduced here) for disclosure of alternating convex and concave portions, as Figure 4 discloses only what Ritchie would likely call adjacent convex portions. According to Murugesh, the grooves provide “areas for the process deposits to collect, and allow residues to ‘run down’ into the grooves 64 for collection.” (Murugesh 5 [0037].) The Examiner concludes that it would have been obvious to use a wavy shield in place of the shield disclosed by Sasaki, and to extend the wavy shield to cover the entire wall, as taught by Murugesh, in order to gain the advantages taught by Murugesh. (FR 4.) The Examiner demonstrates, based on modifications of a cropped version of Figure 1 of Sasaki (FR 5), extensions of the height of the shield by about 75%. In the Examiner’s Answer, the Examiner provides a more detailed analysis, responding to certain criticisms expressed by Ritchie in the Appeal Brief. (Ans. 5.) Ritchie argues, inter alia, that Sasaki teaches that shield 6 should have a smaller diameter than the target. (Br. 5, last para., through 6, 2d full para. (citing Sasaki col. 8, ll. 42–67.); Reply 4, 3d para., through 5.) Thus, Ritchie urges, there is no basis to expand the diameter of the shield to the walls of the chamber, as taught by Murugesh. (Br. 5, first partial paragraph, last sentence; Reply 5, first partial paragraph, last sentence.) Appeal 2018-007785 Application 13/798,021 11 Review of Sasaki supports Ritchie’s arguments. Sasaki reports that “it seems that the plasma density rises because the shield 6 makes the plasma P formation space smaller, or because it prevents the diffusion of the plasma, or for some other such reason.” (Sasaki col. 8, ll. 57–60.) Sasaki teaches that, “[f]rom the standpoint of making the space in which the plasma P is formed smaller, it is better for the shield 6 to have a smaller diameter.” (Id. at ll. 61–63.) If shield 6 is too small, however, “it will hinder the flight of the sputter particles from the target 2 to the substrate 50.” (Id. at ll. 63–65.) Sasaki concludes, “[t]he diameter of the shield 6 should be equivalent to the diameter of the target 2, and should at the least be about 90% of the diameter of the target 2.” (Id. at ll. 65–67.) The Examiner has not provided a credible explanation, supported by evidence of record, of how a shield having the form taught by Murugesh, with a diameter larger than the target, could have been adapted to the substrate processing apparatus taught by Sasaki. Such a modification would appear to render Sasaki’s apparatus inoperable for its intended purpose—a result long held to be incompatible with obviousness. In re Fritch, 972 F.2d 1260, 1265 n.12 (Fed. Cir. 1992), citing In re Gordon, 733 F.2d 900, 902 (Fed. Cir. 1984). The Examiner makes no findings regarding the disclosure or obviousness of the further limitations recited in independent claim 14 or in the dependent claims that cure this flaw. We therefore reverse the appealed rejection. Appeal 2018-007785 Application 13/798,021 12 C. Conclusion The rejection of claims 6, 8–14, and 16–20 is reversed. In summary: Claims Rejected 35 U.S.C. § Reference(s)/Basis Affirmed Reversed 6, 8–14, 16–20 103 Sasaki and Murugesh 6, 8–14, 16–20 REVERSED Copy with citationCopy as parenthetical citation