Ex Parte CohenDownload PDFPatent Trial and Appeal BoardMay 8, 201814077058 (P.T.A.B. May. 8, 2018) Copy Citation UNITED STA TES p A TENT AND TRADEMARK OFFICE APPLICATION NO. 14/077,058 7590 Uri Cohen 4147 Dake Avenue Palo Alto, CA 94306 FILING DATE FIRST NAMED INVENTOR 11/11/2013 Uri Cohen 05/08/2018 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 ATTORNEY DOCKET NO. CONFIRMATION NO. SL-15 5639 EXAMINER SMITH, BRADLEY ART UNIT PAPER NUMBER 2817 MAILDATE DELIVERY MODE 05/08/2018 PAPER 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. PTOL-90A (Rev. 04/07) UNITED STATES PATENT AND TRADEMARK OFFICE BEFORE THE PATENT TRIAL AND APPEAL BOARD Ex parte URI COHEN Appeal2016-004700 Application 14/077,058 Technology Center 2800 Before TERRY J. OWENS, BEVERLY A. FRANKLIN, and CHRISTOPHER M. KAISER, Administrative Patent Judges. OWENS, Administrative Patent Judge. DECISION ON APPEAL STATEMENT OF THE CASE The Appellant appeals under 35 U.S.C. § 134(a) from the Examiner's rejection of claims 37-72. We have jurisdiction under 35 U.S.C. § 6(b ). The Invention The Appellant claims a method for making a metallic interconnect. Claim 37 is illustrative: 3 7. A method for making a metallic interconnect with two or more PVD seed layers for electroplating metallic interconnects over a substrate, the substrate including a patterned insulating layer which comprises at least one opening surrounded by a field, the at least one opening having top comers, sidewalls, and bottom, the at least one opening and the field being ready for depositing one or more seed layers, and the method comprising: Appeal2016-004700 Application 14/077 ,05 8 depositing by a PVD technique, in a PVD chamber, a continuous PVD seed layer over the sidewalls and bottom of the at least one opening and over the field, using a first set of deposition parameters; and depositing by a PVD technique, in a PVD chamber, another PVD seed layer over the substrate, using a second set of deposition parameters, wherein: (a) the two sets include at least one deposition parameter which has different values in the two sets of deposition parameters, (b) said at least one deposition parameter is selected from a group of deposition parameters consisting of substrate bias voltage and sputtering gas pressure, ( c) the combined thicknesses of the seed layers over the field enable uniform electroplating across the substrate, and ( d) the combined seed layers inside the at least one opening leave room for electroplating inside the at least one opening; electroplating inside the at least one opening and over the field a metallic layer comprising a material selected from a group consisting of Cu, Ag, or alloys comprising one or more of these materials; and removing excess electroplated metallic layer overlying the at least one opening and the field, and the seed layers overlying the field. Brown Wetzel Liu The References US 6,187,670 Bl us 5,920,790 us 6,037,258 The Rejections Feb. 13,2001 July 6, 1999 Mar. 14,2000 The claims stand rejected as follows: claims 37-72 under 35 U.S.C. § 112(a) as failing to comply with the enablement requirement, claims 37--44, 48-52, 55-57, 60, 61, 66, and 67 under 35 U.S.C. § 103 over Brown in view of the Appellants admitted prior art (AAP A), claims 45--4 7, 58, and 68 under 35 U.S.C. § 103 over Brown in view of AAPA and Liu, claim 53 under 35 U.S.C. § 103 over Brown in view of AAPA and Wetzel, 2 Appeal2016-004700 Application 14/077 ,05 8 and claims 54, 59, 62---65, and 69--72 under 35 U.S.C. § 103 over Brown in view of AAP A, Liu and Wetzel. OPINION We reverse the rejection under 35 U.S.C. § 112(a) and affirm the rejections under 35 U.S.C. § 103. Rejection under the 35USC§l12(a) enablement requirement A specification complies with the 35 U.S.C. § 112(a) enablement requirement if it allows those of ordinary skill in the art to make and use the claimed invention without undue experimentation. See In re Wright, 999 F.2d 1557, 1561 (Fed. Cir. 1993); Atlas Powder Co. v. E.I. du Pont De Nemours & Co., 750 F.2d 1569, 1576 (Fed. Cir. 1984). Factors which are illustrative, not mandatory, see Amgen, Inc. v. Chugai Pharm. Co., 927 F.2d 1200, 1213 (Fed. Cir. 1991), to be considered in determining whether a disclosure would require undue experimentation "include (1) the quantity of experimentation necessary, (2) the amount of direction or guidance presented, (3) the presence or absence of working examples, (4) the nature of the invention, (5) the state of the prior art, (6) the relative skill of those in the art, (7) the predictability or unpredictability of the art, and (8) the breadth of the claims." In re Wands, 858 F.2d 731, 737 (Fed. Cir. 1988). The Examiner finds that one of ordinary skill in the art could not have carried out the Appellant's claimed method without undue experimentation because "there are a large number of variables such as temperature, pressure, substrate bias, sputtering gas pressure, sputtering gas flow rate, cathodic power, and plasma power density etc." (Final Act. 10), "the applicant fails to disclose detail the [sic] specific conditions (i.e. substrate bias voltage, 3 Appeal2016-004700 Application 14/077 ,05 8 sputtering gas pressure, duration of deposition, and plasma power density) for the deposition of a PVD seed layer that is continuous on the sidewalls and has a thickness of 20-350 angstroms over the field" (id.), "the inventor has not provided any working examples to the deposition conditions such as temperature, pressure, substrate bias, sputtering gas pressure, sputtering gas flow rate, cathodic power, and plasma power density" (id.), and affidavits filed by the Appellant state that "a first deposited seed layer, having a thickness of only between 50-300A on the field, could be continuous on the sidewalls and bottom of the openings - was unexpected and unpredictable because the prior art teaches away from this limitation" (id.) and "disclose the claimed subject matter involved more than routine skill in the art with respect to other references that were state of the art at the time the invention was filed" (Final Act. 10-11 ). The Examiner does not specifically address the Wands factors or provide evidence or technical reasoning in support of the Examiner's findings regarding nonenablement. The Examiner's mere assertions are insufficient for establishing that undue experimentation would have been required for one of ordinary skill in the art to carry out the Appellant's claimed method. As for the affidavits pertaining to the prior art, the Examiner does not address the Appellants' Specification's disclosure and establish that in view of that disclosure and the prior art, one of ordinary skill in the art could not have carried out the Appellant's claimed method without undue experimentation. Accordingly, we reverse the rejection under the 35 U.S.C. § 112(a) enablement requirement. 4 Appeal2016-004700 Application 14/077 ,05 8 Rejections under 35 USC§ 103 Brown discloses regarding the prior art (col. 4, 11. 29--41): To guarantee a minimum seed layer thickness of 5 nm [(50A)J anywhere in the channel opening 106 [(Fig. IC)], including at the lower portion of the sidewalls 109, the seed layer thickness in the wide-open areas tends to be much higher than 5 nm and in the range of 100 to 200 nm on top of the second channel oxide layer 108. Further, an excessively thick seed layer in the upper portion of the sidewalls of the second channel opening 102 would interfere with the subsequent filling of the second channel opening 106 and via opening 118 with the second conductive material. This has become an increasingly greater problem as the width[ s] of the channels and vias have decreased in size due to the size reduction in the semiconductor devices. Brown's invention is a method for forming seed layers in channel or via openings by using a two-stage approach. First, a low temperature deposition of a seed layer is performed at below the temperatures at which agglomeration occurs. This means below 250Q C. for standard thicknesses, below 150Q C. for other thicknesses, and preferably below 1 OOQ C. The absence of agglomeration results in a first seed layer with good adhesion and uniform thickness. Second, a deposition of the seed layer is performed at above 250Q C. At the higher temperatures, the seed material has improved flow and surface mobility which results in better sidewall coverage and enhanced subsequent filling of the channel and via openings by conductive material [(col. 2, 1. 59- col. 3, 1. 4)]. The thickness of the first seed layer 224 [Fig. 2] is determined by the thickness of the second seed layer ... but the combined thickness will be about 5 nm [(col. 4, 11. 60-64)]. Due to the greater surface mobility of the second seed material at higher temperatures, the combined thickness of the first and second seed layers 224 and 226 [(Fig. 3)] on top of the 5 Appeal2016-004700 Application 14/077 ,05 8 second channel oxide layer 108 (B') and the combined thicknesses of the thinnest areas of the combine[d] first and second seed layers 224 and 226 along the sidewalls 109 (A') will be about the same. Accordingly, the sidewall step coverage ( A'/B ') has substantially increased [ (col. 5, 11. 19--26)]. Claims 37-40, 43, 46, 47, 49-52, 55, 57-59, 66-68 and 72 The Appellant acknowledges: As is also well known to those of ordinary skill in the art, controller 80 controls the specific process sequence and process parameters for operation of the various ones of processing chambers 75-79, sometimes referred to in the art as "recipes." For example, in PVD Cu seed layer deposition chamber 77, among other things, controller 80 controls the duration of the sputter deposition, the background pressure, the sputtering gas (such as Argon) pressure and flow rate, the cathodic voltage and power, and/or bias voltage applied to the wafer. Lastly, as is also well known to those of ordinary skill in the art, controller 80 performs these functions in accordance with specific recipes which are data structures that dictate the operation of controller 80 software [(Spec. i-f 64)]. As is well known to those of ordinary skill in the art, the nature of certain deposition techniques, such as ion plating or other PVD techniques, can be made more conformal, or less conformal, by varying the deposition parameters (or variables, or conditions). For example, increasing the (partial) pressure during ion plating and other PVD techniques, tends to increase scattering of the depositing atoms (or ions), thereby making the deposition more isotropic and conformal. Similarly, biasing the substrate has an effect on the nature of the deposit. For example, in ionized metal plasma (IMP), self ionized plasma (SIP), hollow cathode magnetron (HCM), and ion plating deposition techniques, increasing the (negative) bias voltage further accelerates positive ions (of the depositing metal) towards the substrate, thereby improving the filling of small openings. At the same time, the higher (negative) bias also 6 Appeal2016-004700 Application 14/077 ,05 8 increases the removal rate (or back-sputtering) from the top comers or the openings and the field, thereby rendering the deposition to be more conformal [(Spec. i-f 66)]. The Appellant asserts that "Appellant's admitted prior art (AAPA) of the effects of varying certain deposition variables on a single PVD seed layer, does not affect in any way embodiments of the invention which disclose two PVD seed layers deposited with two different values of the deposition parameters" (App. Br. 34). The knowledge in the art of varying deposition parameters including substrate bias voltage and sputtering gas pressure to control conformality applies to each layer deposited and, therefore, applies to each of Brown's seed layers. The Appellant argues that "a POSIT A [person of ordinary skill in the art] would have known that [Brown's] teaching (a combined thickness of the two seed layers over the field of only about 50A) was entirely inadequate, because the prior art taught that a minimum thickness of the seed layer( s) over the field, of at least an order of magnitude larger, was essential to enable adequate (or uniform) electroplating" (App. Br. 32). Brown discloses that to guarantee a seed layer thickness of 5 nm (50A) anywhere in a channel opening, the prior art seed layer's thickness over the field had to be in the range of 100-200 nm (1000-2000A) (col. 4, 11. 29--34), whereas Brown's two-temperature method reduces the required seed layer thickness over the field to 5 nm and substantially increases sidewall step coverage (col. 2, 1. 59- col. 3, 1. 13; col. 4, 11. 60-63; col. 5, 11. 19--26). 7 Appeal2016-004700 Application 14/077 ,05 8 The Appellant asserts that "[ t ]he proposed modification will also change Brown et al.' s principle of operation (by eliminating the two-stage substrate temperature depositions)" (App. Br. 30), "[ s ]ince Brown et al. already asserts good conformality and smaller overhangs, the POSIT A would have no motivation to modify Brown et al.' s process by AAP A's process, to (allegedly) obtain the same result" (App. Br. 31 ), "while AAP A refers to a prior art single PVD seed layer, it does not describe two PVD seed layers deposited under two different substrate bias values" (id.), and "a POSIT A would have understood from Chen '181 and Chiang et al. that, for a PVD seed layer to be continuous inside narrow openings, it must have a minimum thickness between 500-1 oooA over the field" (App. Br. 41 ). As acknowledged by the Appellant, it was well known in the art to control substrate bias voltage and sputtering gas pressure, and to use substrate bias voltage control to achieve conformality (Spec. i-fi-1 64, 66). Hence, one of ordinary skill in the art, through no more than ordinary creativity, would have chosen for the deposition of each seed layer in Brown's two-temperature process a substrate bias voltage that contributes to achieving Brown's desired conformality, and would have chosen a sputtering gas pressure suitable for depositing that layer. See KSR Int 'l Co. v. Teleflex Inc., 550 U.S. 398, 421 (2007) ("A person of ordinary skill is also a person of ordinary creativity, not an automaton"). The Appellant argues that "[b ]ecause Brown et al. teaches a combined thickness of its two PVD seed layers of only about 50A over the field, while the prior art taught that a minimum thickness over the field of at least 5ooA was essential for adequate (or uniform) electroplating, a POSIT A would consider Brown et al. as an unreliable reference" (App. Br. 33), and 8 Appeal2016-004700 Application 14/077 ,05 8 "because a POSIT A would know that Brown et al.' s teaching of a combined thickness of its two PVD seed layers of only 50A over the field is unreliable and inoperable, the POSIT A would not use or combine Brown et al. with any other prior art to meet the limitations of the claims" (Reply Br. 15) .. Brown discloses that to guarantee a minimum seed layer thickness of 5 nm anywhere in the channel opening, prior art methods require a 100- 200 nm seed layer thickness over the field, whereas Brown's two-temperature method requires only a 5 nm thickness over the field (col. 2, 1. 59-col. 3, 1. 13; col. 4, 11. 29-34, 60-63; col. 5, 11. 19-26). The Appellant does not establish that without undue experimentation, one of ordinary skill in the art given not only the prior art but also Brown's disclosure could not have carried out Brown's claimed method to form over the field a 5 nm seed layer that enables uniform electroplating across the substrate. Claims 48 and 60-65 The Appellant asserts that Brown's overhangs would interfere with void-free electrofilling of narrow openings such as 0.1---0.13µm openings (App. Br. 37-38, 60). Brown's disclosures that the total seed layer is only 5 nm thick and has good sidewall step coverage (col. 4, 11. 60-63; col. 5, 11. 19-26) would have indicated to one of ordinary skill in the art that the seed layer overhangs would not interfere with void-free electrofilling of narrow openings including 0 .1---0 .13 µm openings. 9 Appeal2016-004700 Application 14/077 ,05 8 Claims 41, 42 and 56 The Appellant asserts that Brown would not have enabled one of ordinary skill in the art to successfully deposit a continuous PVD seed layer inside an opening having an aspect ratio (AR) of 8:1to14:1 (App. Br. 45). The Appellant acknowledges that the desirability of depositing seed layers in high AR openings was known in the art, and that future trenches and via openings will have ARs of 8:1-20:1 or higher (Spec. i-fi-f 12-14). Thus, one of ordinary skill in the art would have been motivated to use Brown's method to form seed layers in openings having 8: 1-20: 1 ARs. Brown's disclosures that the combined seed layer thickness in the opening and over the field is only 5 nm (col. 4, 11. 60-63) and that the seed layer has good step coverage (col. 5, 11. 19-26) would have provided one of ordinary skill in the art with a reasonable expectation of success in doing so. See In re O'Farrell, 853 F.2d 894, 903---04 (Fed. Cir. 1988) ("Obviousness does not require absolute predictability of success .... For obviousness under§ 103, all that is required is a reasonable expectation of success"). Claims 44 and 45 The Appellant asserts that Brown would not have suggested forming the seed layers in either the same chamber or separate chambers (Br. 4 7, 51 ). Brown's disclosure that except for a higher temperature, the second seed layer's deposition process generally is a continuation of the first seed layer's deposition process (col. 5, 11. 7-9) would have suggested, to one of ordinary skill in the art, carrying out both processes in the same chamber. The well-known use of cluster tools to deposit layers in separate chambers without breaking the vacuum (Spec. i163) would have led one of ordinary skill in the art, through no more than ordinary creativity, to deposit Brown's 10 Appeal2016-004700 Application 14/077 ,05 8 seed layers in separate chambers. See KSR, 550 U.S. at 418 (in making an obviousness determination one "can take account of the inferences and creative steps that a person of ordinary skill in the art would employ"). Claims 53, 54 and 69-71 The Appellant asserts that one of ordinary skill in the art would not have used a collimated sputtering chamber, a hollow cathode magnetron sputtering chamber, a self-ionized plasma sputtering chamber or an ionized metal plasma sputtering chamber to carry out Brown's sputter deposition of the seed layers (App. Br. 70). One of ordinary skill in the art, given that Brown's seed layers are deposited by sputtering (col. 3, 11. 5-13), would have selected a suitable sputtering chamber from the well-known sputtering chambers which, as acknowledged by the Appellant (Spec. 8), include those listed above (Spec. if 8). Thus, we are not persuaded of reversible error in the rejections under 35 U.S.C. § 103. DECISION/ORDER The rejection of claims 37-72 under the 35 U.S.C. § 112(a) enablement requirement is reversed. The rejections under 35 U.S.C. § 103 of claims 37--44, 48-52, 55-57, 60, 61, 66 and 67 over Brown in view of AAPA, claims 45--47, 58 and 68 over Brown in view of AAPA and Liu, claim 53 over Brown in view of AAPA and Wetzel, and claims 54, 59, 62- 65 and 69-72 over Brown in view of AAP A, Liu and Wetzel are affirmed. It is ordered that the Examiner's decision is affirmed. 11 Appeal2016-004700 Application 14/077 ,05 8 No time period for taking any subsequent action in connection with this appeal may be extended under 37 C.F.R. § 1.136(a). AFFIRMED 12 Copy with citationCopy as parenthetical citation