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 .
Election/Restrictions
Claims 1-17, and 21-24 are pending in this application.
Applicant’s election without traverse of invention I ( in the reply filed on November 11, 2025 is acknowledged.
Claims 18-20 withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected invention, there being no allowable generic or linking claim. Election was made without traverse in the reply filed on November 11th, 2025.
Information Disclosure Statement
The information disclosure statements (IDS) submitted on 05/23/2025 are in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statement is being considered by the examiner.
Response to Amendment
This Office Action is in response to Applicant’s Amendment filed 11/11/2025. Claims 17-20 are cancelled. New claims 21-24 are added. The Examiner notes that claims 1-17 and 21-24 are examined.
Drawings
The drawings are objected to because labeling at theCorrected drawing sheets in compliance with 37 CFR 1.121(d) are required in reply to the Office action to avoid abandonment of the application. Any amended replacement drawing sheet should include all of the figures appearing on the immediate prior version of the sheet, even if only one figure is being amended. The figure or figure number of an amended drawing should not be labeled as “amended.” If a drawing figure is to be canceled, the appropriate figure must be removed from the replacement sheet, and where necessary, the remaining figures must be renumbered and appropriate changes made to the brief description of the several views of the drawings for consistency. Additional replacement sheets may be necessary to show the renumbering of the remaining figures. Each drawing sheet submitted after the filing date of an application must be labeled in the top margin as either “Replacement Sheet” or “New Sheet” pursuant to 37 CFR 1.121(d). If the changes are not accepted by the examiner, the applicant will be notified and informed of any required corrective action in the next Office action. The objection to the drawings will not be held in abeyance.
Specification
The disclosure is objected to because of the following informalities: the unknown unit "um" is repeatedly used throughout the specification. Examiner notes that it is likely that the unit "μm," denoting micrometers, was intended. Appropriate correction is required.
Claim Objections
Claims objected to because of the following informalities: the unknown unit "um" is repeatedly used throughout the specification. Examiner notes that it is likely that the unit "μm," denoting micrometers, was intended. Appropriate correction is required.
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, 12, 15, and 22 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.
Claims 1, 4, and 10 rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being incomplete for omitting essential elements, such omission amounting to a gap between the elements. See MPEP § 2172.01. The omitted elements are: the definition of. The term “percentage of (111) orientation of copper” could refer to multiple distinct material properties. For example, this language could refer to face-centered cubic copper in a solid lattice which contains copper atoms in the (111) orientation when viewed from the plane defined by the (111) Miller index, or to textured nano-twinned copper in which copper is in the (111) orientation along grain boundaries. As set forthe under 35 U.S.C. §112, second paragraph, as indefinite.” 89 USPQ2d 1207, 1211 (Bd. Pat. App. & Int. 2008). For the purposes of this action, this language will be interpreted to refer to the definition given in the specification: “when measuring crystal orientations on any cross-section of the copper pillar 294, a (111) crystal orientation has a proportion of 90% or 97% (for claim 10) or more among all crystal orientations (e.g., (100) crystal orientation, (110) crystal orientation, (111) crystal orientation) on that cross-section of the copper pillar 294.”
Claims 3, 12, 17, and 22 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being incomplete for omitting essential structural cooperative relationships of elements, such omission amounting to a gap between the necessary structural connections. See MPEP § 2172.01. The omitted structural cooperative relationships are: the definition ofness” could refer to the average roughness obtained by the arithmetic mean position of points on the surface along a direction perpendicular to the substrate, or the root-mean square (RMS) of the position of the points on the surface along a direction perpendicular to the substrate. As set forth in In re Miyazaki, “if a claim is amenable to two or more plausible claim constructions, the USPTO is justified in requiring the applicant to more precisely define the metes and bounds of the claimed invention by holding the claim unpatentable under 35 U.S.C. §112, second paragraph, as indefinite.” 89 USPQ2d 1207, 1211 (Bd. Pat. App. & Int. 2008). For the purposes of this action, the term “average roughness” will be interpreted to encompass either the arithmetic or the RMS roughness in a direction perpendicular to the substrate.
The term “about” in claim 7 is a relative term which renders the claim indefinite. The term “a ratio of” is not defined by the claim, the specification does not provide a standard for ascertaining the requisite degree, and one of ordinary skill in the art would not be reasonably apprised of the scope of the invention. The claim refersld be constructed. For the purposes of this action, the “about’ term will be considered in the range given by the specification: “10um ≤ S1≤ 130 um, and 10um < S2 < 130 um,” that is, the metes and bounds of the word “about” will be evaluated under the assumption that both the “first distance” and “second distance” fall in the range of 10 and 130 micrometers as it relates to, for example, manufacturing tolerances.
Claim 9 is rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being incomplete for omitting essential structural cooperative relationships of elements, such omission amounting to a gap between the necessary structural connections. See MPEP § 2172.01. The omitted structural cooperative relationships are: the metes and bounds of the word “tilted.” Claim 9’s language “wherein the lower sidewall surface comprises a tilted sidewall surface” does not define a feature in which the mentioned sidewall surface is tilted relative to. Therefore, the word “tilted” can be interpreted in this context to encompass any and all orientations, and is rendered indefinite. For the purposes of this action, this claim will be interpreted to mean that the lower sidewall surface is neither perpendicular nor parallel to the surface of the substrate.
Claim 12 is rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being incomplete for omitting essential structural cooperative relationships of elements, such omission amounting to a gap between the necessary structural connections. See MPEP § 2172.01. The omitted structural cooperative relationships are: which of the two copper pillars described in claim 11 has an average roughness on the top surface of “between about 30um and about 130um.” The examiner notes that the “second copper pillar” of claim 11 has an ambiguous roughness, and therefore it is within the broadest reasonable interpretation of claim 12 for the second pillar to optionally comprise a rough upper surface. For the purposes of this action the “first copper pillar,” which necessarily comprises a rough top surface, will be taken to have an average roughness (calculated by arithmetic average or rms roughness on a direction perpendicular to the substrate) within the described range.
Dependent claims 1-10 are rejected at least on the same basis as the claims upon which they depend.
Claim Rejections - 35 USC § 102
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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.
The examiner notes that translations of foreign patent literature are utilized for the purposes of this action. All paragraph numbers and quotes hereafter refer to the positions and quotations as they appear in the translations attached to this application.
Claim(s) 21 and 24 is/are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Li (CN 101621044 A).
The following is the full quotation of claim 21 with superscripts added for later referencing:
A semiconductor structure, comprising: a contact pad1 over a substrate2; an under-bump metallization (UBM) layer over the contact pad3; a copper pillar over UBM layer and electrically coupled to the contact pad via the UBM layer4, wherein the copper pillar comprises: a lower portion surrounded by the UBM layer5, a middle portion over the lower portion, wherein middle portion has a width that gradually increases along a direction from a bottom surface of the copper pillar towards a top surface of the copper pillar6, wherein an edge of the middle portion is aligned with an edge of the UBM layer7, and an upper portion over the middle portion8.
With respect to claim 21, Li FIG 2 discloses a “connector” wherein it is stated that “in practical application, connector 26 is often made of copper, and often with a ball bottom metal layer 24 is formed between the welding pad 22” (Preferred embodiment paragraph 3). This discloses a copper pillar4 above a UBM layer3 that is itself above a contact pad1. Figure 3 further shows that this structure is further disposed above a substrate1 and that the disclosed copper pillar increases in width from the bottom surface of the copper pillar to the top surface6, and comprises an upper portion8 and a lower portion surrounded by the UBM5. Finally, it is shown that the edge of the middle portion is aligned with an edge of the UBM layer7.
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With respect to claim 24, Li further teaches that the copper pillar structure described in the previous paragraph comprises the following limitation from claim 24: “a solder cap on the copper pillar, wherein a bottom surface of the solder cap is substantially planar.” This is shown in the image included in the previous paragraph.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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.
Claim(s) 1-2, 4, 6, and 10 is/are rejected under 35 U.S.C. 103 as being obvious over Lin (US 20210104478) in view of Bergman (WO-2023027917-A1).
With respect to claim 1, The following is a quote from Lin: “as shown in FIG. 1, the semiconductor apparatus 10 includes a semiconductor substrate 12, a first passivation layer (PASV) 14, a second passivation layer (re passivation layer, Re-PASV) 16, an under bump metal (UBM) layer 18, a stress buffer layer 20, a copper pillar 22 and a solder structure 24. The semiconductor substrate 12 has at least one metal pad 26 thereon. The semiconductor substrate 12 may be a silicon wafer or a layer of silicon-containing material, and integrated circuits may be formed therein or thereon.”
Lin further teaches a semiconductor structure with a first contact pad over a substrate, a first UBM layer over the first contact pad, a first metal pillar comprising copper (“copper pillar 22”), and solder cap (“solder structure”).
However, Lin fails to teach that the copper pillar has a percentage of (111) copper crystal orientation - measured on any plain - of 90% or more.
Bergman, in an application named “Nanotwin Materials in Semiconductor Devices” teaches “polycrystalline copper with nanotwin copper (NTCu), which has a <1,1,1> crystallographic orientation. (paragraph 0023). Additionally, Bergman discloses that the “copper-containing material 430 may include. . . greater than or about “90 wt.% NTCu or more” (paragraph 0040). Additionally, Bergman teaches that “in many instances, metals with a nanotwin crystal structure are less susceptible to oxide formation and more easily bond to similar metal surfaces at lower bonding temperatures and pressures” (paragraph 0012). Additionally, Bergman teaches a semiconductor structure which utilizes this NTCu in figure 4B; the structure features the NTCu on top of a “barrier layer” additionally, “the barrier layer 425 may be made of an electrically conductive material, such as a metal other than copper . . .”
Therefore, Bergman teaches a nanotwinned copper crystal with 90% or more aligned in the (111) orientation when viewed from a particular plane (as a 90% weight of copper crystal requires that such a crystal structure also accounts for 90% of the copper in the structure) sitting atop a “barrier layer” which acts as a UBM layer. The title of Bergman’s disclosure being “Nanotwin Materials in Semiconductor Devices” further suggests to one of ordinary skill in the art to utilize this material in a semiconductor device.
It would be obvious to one of ordinary skill in the art to modify Lin with Bergman such that the aforementioned copper pillar structure taught by Lin (which is itself a part of the aforementioned semiconductor structure taught by Lin) comprises the copper crystal orientation content described by Bergman, in order to garner the known benefits taught by Bergman, as the use of conventional materials to perform their known function is prima-facie obvious (MPEP 2144.04).
With respect to claim 2, Lin further teaches a planar top surface on the aforementioned copper pillar structure - which is a part of the aforementioned semiconductor structure – in FIG. 1.
With respect to claim 4, Lin further teaches/replicates the semiconductor structure of claim 1, with the added limitation that the second semiconductor structure’s copper pillar has “less (111) copper crystal orientation than the first pillar.”
It is obvious that, given any two copper pillars, that one of those copper pillars will have less (111) copper orientation along any plane than the other, because there exists no manufacturing process that can create two pillars of exactly the same (111) copper crystal orientation along any plane, due to inevitable manufacturing variation. Thus, the pillar with a greater (111) copper orientation percentage in this context can be named “the first metal pillar” and the pillar with a lesser (111) copper orientation percentage can be named the “second metal pillar,” and any two copper pillars (in which one of the copper pillars comprises 90% or more (111 copper orientation along a particular plane) would fall under the limitations set forth by claim 4. The examiner notes that the first metal pillar, which has a greater (111) copper orientation percentage than the first, is constrained to have a flat upper surface by the limitations set forth by claim 2; the shape of the upper surface of the second metal pillar (comprising a lesser (111) copper crystal orientation percentage along a particular plane) is left ambiguous by the claim language of claim 4, and the second metal pillar could, for example, comprise a planar top surface under the broadest reasonable interpretation of claim 4. For these reasons, it is within the broadest reasonable interpretation of claim 4 to simply introduce a second semiconductor structure as described in claim 1.
Regarding claim 6, Bergman further teaches that “contact surfaces formed from electroplated NTCu can also be characterized by a high average surface roughness” (paragraph 0023).
Therefore, if the second copper pillar possess a lesser (111) copper crystal orientation percentage than the first pillar, as is claimed in claim 6, it is obvious that the second copper pillar would possess a lesser average roughness than the first pillar as explained above.
Regarding claim 10, Bergman further discloses a nanotwinned copper crystal with 90% or more aligned in the (111) orientation when viewed from a particular plane. The examiner notes that there is no reasoning given as to why raising the (111) copper crystal orientation percentage to a level of “no less than 97%” (claim 10) is critical to the claimed invention. Thus, this limitation rendered obvious due to Lin in view of Bergman, as Bergman teaches a range of (111) copper crystal orientation that is close to the non-critical claimed range (97%+). See (In re Dreyfus, 73 F.2d 931, 934, 24 USPQ 52, 55 (CCPA 1934)).
Claim(s) 3 is/are rejected under 35 U.S.C. 103 as being unpatentable over Lin (US 20210104478 A1) in view of Bergman (WO 2023027917 A1) and Rokugawa (US 20160005685 A1).
Lin teaches a semiconductor structure with a first contact pad over a substrate, a first UBM layer over the first contact pad, a first metal pillar comprising copper (“copper pillar 22”) with a planar top, and solder cap (“solder structure”).
However, Lin fails to teach that the copper pillar has a percentage of (111) copper crystal orientation - measured on any plain - of 90% or more and a roughness of between about 30 and 130 micrometers on the upper surface of a copper pillar.
Bergman teaches a nanotwinned copper crystal with 90% or more aligned in the (111) orientation when viewed from a particular plane sitting atop a “barrier layer” which acts as a UBM layer. In addition, Bergman teaches a motivation to raise the (111) copper crystal orientation percentage to this range.
However, Bergman fails to teach some of the specific structural components of the semiconductor device in claim 1 (a metal feature, contact pad over a substrate, a metal pillar with a planar top, and a solder cap on the metal pillar) and fails to explicitly teach a UBM layer underneath a (111) copper crystal containing structure (although this is implied).
Rokugawa teaches a metal pillar wherein “metal post is formed from, for example, copper (Cu)” (paragraph 0026). Additionally, “the surfaces of the wiring layer 25a and the metal posts 27 have a roughness indicated by a surface roughness Ra value that is in the range of, for example, 100 to 500 μm (e.g., 350 μm)” (paragraph 0050). Further, this structure is connected to a solder bump: “Each pad 60b is connected to the corresponding metal post 27 of the wiring substrate 10 by the solder” (paragraph 0050). Furthermore, the “wiring layer 25a” is shown in FIG. 3A to be in contact with the copper pillar (“metal post”); the “wiring layer” can therefore be interpreted to be a contact pad. The copper pillar (“metal post”) of FIG. 3A is also shown to have a planar top surface.
It would have been obvious to one of ordinary skill in the art to modify Lin with Bergman and Rokugawa such that the semiconductor and copper pillar structure taught by Lin comprises the (111) copper crystal percentage taught by Bergman for the reasons outlined by Bergman, and to additionally implement the specific roughness range on the top of that copper pillar structure taught by Bergman. One having reasonable skill in the art is also motivated to implement this roughness on the top of the metal pillar to, for example, increase the contact area between a solder cap and the copper pillar to increase electrical and thermal conductivity across the barrier between the copper pillar structure and the solder cap structure.
Claim(s) 5 is/are rejected under 35 U.S.C. 103 as being obvious over Lin (US 20210104478 A1) in view of Bergman (WO 2023027917 A1), and Takeuchi (US 20190304942)
Lin teaches a semiconductor structure with a first contact pad over a substrate, a first UBM layer over the first contact pad, a first metal pillar comprising copper (“copper pillar 22”), and solder cap (“solder structure”).
However, Lin fails to teach that the copper pillar has a percentage of (111) copper crystal orientation - measured on any plain - of 90% or more, a second copper pillar structure of identical nature except that it comprises less (111) copper crystal orientation percentage along a particular plane than the first pillar and that the copper pillar that comprises less (111) copper crystal orientation percentage along a particular plane than the first copper pillar comprises a substantially smooth convex upper surface.
Bergman teaches a nanotwinned copper crystal with 90% or more aligned in the (111) orientation when viewed from a particular plane sitting atop a “barrier layer” which acts as a UBM layer. Further, Bergman teaches a motivation to use this kind of material in a semiconductor device.
However, Bergman fails to teach some of the specific structural components of the semiconductor device in claim 4 (a metal feature, contact pad over a substrate, a metal pillar with a flat upper surface, and a solder cap on the metal pillar, and a copy of each of these elements which includes a second copper pillar, which has less (111) copper crystal orientation percentage along a particular plane than the first copper pillar, and that second pillar having a substantially smooth convex upper surface) and fails to explicitly teach a UBM layer underneath a (111) copper crystal containing structure (although this is implied by Bergman), and a second UBM layer underneath a second (111) copper crystal containing structure (this is not implied).
Takeuchi teaches two “posts” in which “The posts 911 and 921 may be formed through copper electroplating” (paragraph 0019). In addition, one of these posts comprises a flat upper surface and the other post comprises a convex upper surface, as shown in FIG. 1B. Furthermore, these metal posts comprise a solder cap on its upper surface. Further, Takeuchi teaches “According to further detailed studies conducted by the inventors of the present invention with regard to this phenomenon, the provision of a concave surface for the post 921 of the large-diameter terminal 920 as illustrated in FIG. 2 causes the height of the small-diameter terminal 910 and the large-diameter terminal 920 to be substantially aligned after the reflow process. This arrangement reduces the occurrence of connection failures and short circuiting, thereby improving the reliability of connections.” Therefore, Takeuchi teaches two copper pillars, in which one comprises a planar top surface and the other comprises a convex top surface, both of which have solder caps. Additionally, Takeuchi further states that this variation between flat and convex upper surfaces provides an advantage in interconnect reliability when dimensions between copper pillar structures vary.
The examiner notes that the claim language of claim 6 specifically pairs a first copper pillar with greater (111) crystal orientation (that is of 90% or more) with a flat upper surface and pairs a second copper pillar with less (111) copper orientation percentage with a convex upper surface. Expanding upon the reasoning used in the rejection of claim 4 under 35 U.S.C. 103, any reasonable usage of the semiconductor structure described by claim 1 would contain a plurality of copper pillars. It has been previously explained that manufacturing errors will inevitably lead to some copper pillars having more (111) copper crystal orientation percentage than others if a semiconductor device with a plurality of copper pillars is constructed under the specifications set forth by claim 1; furthermore, if some of those copper pillars comprise flat upper surfaces and convex lower surfaces (as taught by Takeuchi), it is therefore inevitable that some of those copper pillars with flat upper surfaces will have more (111) copper crystal orientation than another copper pillar with a convex upper surface, meeting the conditions set forth by claim 5. That is to say, the conditions set forth by claim 5 pertain to a plurality of semiconductor structures described by claim 1, with the additional limitation that some of those semiconductor structures comprise flat upper surfaces and the remaining semiconductor structures comprise convex upper surfaces.
It would have been obvious to one of ordinary skill in the art to modify Lin with Bergman and Takeuchi such that the metal post which is itself part of the larger semiconductor structure taught by Lin comprises the (111) copper crystal orientation percentage taught by Bergman, and to utilize a combination of flattened and convex upper surfaces to a plurality of such a copper post as taught by Takeuchi (noting that reasonable uses of the claimed semiconductor structure of claim 5 require a plurality of such semiconductor structures). A person having ordinary skill in the art is motivated to have a combination of flat and convex upper surfaces on copper pillar structures to, for example, increase the reliability of connections between copper pillar structures in the case that the sizes of those copper pillar structures vary (which is within the scope of claim 5).
Claim(s) 8-9 is/are rejected under 35 U.S.C. 103 as being obvious over Lin (US 20210104478 A1) in view of Bergman (WO 2023027917 A1) and C. Lin (US 20210104478 A1).
With respect to claim 8, Bergman teaches a nanotwinned copper crystal with 90% or more aligned in the (111) direction. Further, Bergman teaches a motivation to use this kind of material in a semiconductor device.
However, Bergman fails to teach some of the specific structural components of the semiconductor device in claim 1 (a metal feature, contact pad over a substrate, a metal pillar, and a solder cap on the metal pillar) and fails to explicitly teach a UBM layer underneath a (111) copper crystal containing structure (although this is implied).
C. Lin teaches, in FIG. 1, a copper pilar having a lower sidewall surface and an upper sidewall surface wherein the lower sidewall surface and upper sidewall surface form an obtuse angle. Further, in FIG. 8, C. Lin teaches that this structure reduces the normalized stress applied to the substrate compared to a vertical copper pillar structure.
It would have been obvious to one of ordinary skill in the art to modify Lin with Bergman and C. Lin such that the copper pillar in the semiconductor structure taught by Lin comprises the (111) copper orientation taught by Bergman for the reasons outlined by Bergman, and the shape taught by C. Lin. One of ordinary skill in the art would be motivated to shape a copper pillar structure this way due to the reduction in normalized stress taught by C. Lin.
With respect to claim 9, C. Lin further teaches a lower portion of a copper pillar structure which is tilted with respect to a substrate, as seen in the previously provided figure.
Claim(s) 11-12 is/are rejected under 35 U.S.C. 103 as being obvious over Huang (US 20210159197 A1) in view of Rokugawa (US 20160005685 A1).
Regarding claim 11, Huang teaches, in FIG 3G, a semiconductor structure with two metal features (“metal layers”) in a dielectric layer, a passivation layer (“insulating layer”), two contact pads over this passivation layer, one of which is electrically coupled to a metal feature, and two copper pillars over these contact pads.
However, Huang fails to teach that the top surface of one of these metal pillars is roughened. In addition, Huang fails to explicitly teach that both of the disclosed metal features are electrically coupled to a contact pad.
Rokugawa teaches a metal pillar (“metal post”) wherein “metal post is formed from, for example, copper (Cu)” (paragraph 0026). Additionally, Rokugawa discloses that “the surface of the structure illustrated in FIG. 3A (surfaces of wiring layer 25a and metal posts 27) undergoes a roughening process” (Paragraph 0049).
It would have been obvious to one of ordinary skill in the art to modify Huang with Rokugawa such that the semiconductor structure taught by Huang comprises the roughened top surface taught by Rokugawa. The examiner notes that Huang does not explicitly teach two metal features in a dielectric layer electrically coupled to a contact pad, but rather one metal feature coupled to a contact pad and a second contact pad that is not electrically coupled to the contact pad directly over it. It would have been obvious to one having ordinary skill in the art to couple the metal feature to the contact pad described by Huang in the same manner as the first metal feature described by Huang. Additionally, one having ordinary skill in the art would be motivated to roughen the top surface of one of the metal pillars in order to increase the contact area between the copper pillar and a contact surface in order to, for example, increase the thermal and electrical coupling therebetween. The examiner notes that the scope of this claim does not require that the top surface of the second pillar be unroughened. Therefore, one does not need a motivation to roughen the top surface of the first pillar and leave unroughened the surface of the second pillar, one only needs a motivation to roughen the top surface of a copper pillar (which has been described).
Regarding claim 12, Rokugawa further teaches “the surfaces of the wiring layer 25a and the metal posts 27 have a roughness indicated by a surface roughness Ra value that is in the range of, for example, 100 to 500 μm (e.g., 350 μm)” (paragraph 0050). Further, this structure is connected to a solder bump: “Each pad 60b is connected to the corresponding metal post 27 of the wiring substrate 10 by the solder” (paragraph 0050). Furthermore, the “wiring layer 25a” is shown in FIG. 3A to be in contact with the copper pillar (“metal post”); the “wiring layer” can therefore be interpreted to be a contact pad.
Claim(s) 13-14 is/are rejected under 35 U.S.C. 103 as being obvious over Huang (US 20210159197 A1) in view of Rokugawa (US 20160005685 A1) and C. Lin (US 20210104478 A1).
Regarding claim 13, Huang teaches, in FIG 3G, a semiconductor structure with two metal features (“metal layers”) in a dielectric layer, a passivation layer (“insulating layer”), two contact pads over this passivation layer, one of which is electrically coupled to a metal feature, and two copper pillars over these contact pads.
However, Huang fails to teach that the top surface of one of these metal pillars is roughened. In addition, Huang fails to explicitly teach that both of the disclosed metal features are electrically coupled to a contact pad. In addition, Huang additionally fails to teach that a bottom width of one of the copper pillars is greater than the top width of that copper pillar.
Rokugawa teaches a metal pillar (“metal post”) wherein “metal post is formed from, for example, copper (Cu)” (paragraph 0026). Additionally, Rokugawa discloses that “the surface of the structure illustrated in FIG. 3A (surfaces of wiring layer 25a and metal posts 27) undergoes a roughening process” (Paragraph 0049).
However, Rokugawa fails to teach the additional portions of the semiconductor structure described by claim 11 (namely, two metal features in a dielectric layer, electrically coupled to a two contact pads that are specifically over a passivation layer, and copper pillars over those contact pads, with one of those copper pillars having a bottom portion with a greater width than a top portion).
C. Lin teaches, in FIG. 1, a bottom width that is wider than a top width of a copper pillar. Further, C. Lin Teaches in FIG. 8 that this structure reduces the normalized stress applied to the structure below the copper pillar.
It would have been obvious to one of ordinary skill in the art to modify Huang with Rokugawa and C. Lin such that at least one of the copper pillars which are part of the larger semiconductor structure described by Huang comprises a roughness on the top portion surface, as taught Rokugawa, and to modify the structure of that roughened copper pillar such that the lower portion of the copper pillar has a greater width than the upper portion of the copper pillar, to garner the benefits described by C. Lin. The examiner notes that the roughness of the upper portion of the second copper pillar, and the relative widths of the lower and upper portions of the second copper pillar are left ambiguous by the claim language of claim 11 and 12. That is to say, the “second pillar” may or may not be roughened and may or may not have a wider width of its bottom portion relative to the width of its top portion in order to fit within the scope of claim 12. It would have been obvious to one of ordinary skill in the art to make both pillars in the manner outlined by Huang in view of Rokugawa and C. Lin for the aforementioned reasons.
Regarding claim 14, C. Lin further teaches the aforementioned copper pillar structure having an upper portion with uniform width and a lower portion having non-uniform width. A person having ordinary skill in the art is again motivated to create this structure because of the reduction in normalized stress on materials below the copper pillar as detailed in FIG. 8.
It would have been obvious to one of ordinary skill in the art to modify Huang with Rokugawa and C. Lin such that at least one of the copper pillars which are part of the larger semiconductor structure described by Huang comprises a roughness on the top portion surface, as taught Rokugawa, and to modify the structure of that roughened copper pillar such that the lower portion of the copper pillar has a nonuniform width and the upper portion of the copper pillar has a uniform width, to garner the benefits described by C. Lin (namely, a reduced normalized stress on the lower structure). The examiner notes that the roughness of the upper portion of the second copper pillar, and the uniformity of the upper portion and lower portion of the second copper pillar are left ambiguous by the claim language of claim 11 and 12. Thus, one does not need to have a motivation to both roughen one copper pillar, and make wider the lower portion of that copper pillar structure relative to the upper portion of the copper pillar and to either leave the second pillar’s top surface unroughened or leave the second pillar’s structure uniform (or in any other shape not described by claim 12) in order to construct an embodiment of the semiconductor structure described by claim 12. That is to say, the “second pillar” may or may not be roughened and may or may not have a nonuniform width of its bottom portion and a uniform width of its top portion in order to fit within the scope of claim 12. It would have been obvious to one of ordinary skill in the art to make two pillars in the manner outlined by Huang in light Rokugawa and C. Lin for the aforementioned reasons.
Claim(s) 22 is/are rejected under 35 U.S.C. 103 as being obvious over Li (CN 200810040231 A) in view of Rokugawa (US 20160005685 A1)
Li teaches the limitations set forth by claim 21. However, Li fails to teach that the upper surface of this copper pillar has a roughness “between about 30um and 130um.”
Rokugawa teaches a metal pillar wherein “metal post is formed from, for example, copper (Cu)” (paragraph 0026). Additionally, “the surfaces of the wiring layer 25a and the metal posts 27 have a roughness indicated by a surface roughness Ra value that is in the range of, for example, 100 to 500 μm (e.g., 350 μm)” (paragraph 0050). In addition, this is connected to a solder bump: “Each pad 60b is connected to the corresponding metal post 27 of the wiring substrate 10 by the solder.”
It would have been obvious to one of ordinary skill in the art to modify Li with Rokugawa such that the upper surface of the copper pillar structure, which is a part of the overall semiconductor structure described by Li, comprises a roughened surface of an average roughness in the range described by Rokugawa. One of ordinary skill in the art would be motivated to apply this roughness to the upper surface of such a copper pillar structure because doing so would, for example, increase the surface are of contact between the copper pillar and a contact surface, increasing the overall thermal and electrical coupling therebetween.
Claim(s) 23 is/are rejected under 35 U.S.C. 103 as being obvious over Li (CN 101621044 A) in view of C. Lin (US 20210104478 A1).
Li teaches the limitations set forth by claim 1. However, Li fails to teach a copper pillar structure which is a part of the aforementioned semiconductor structure in which the upper portion of the copper pillar structure has a “substantially uniform width.”
C. Lin teaches, in FIG. 1, a bottom width on a copper pillar that is wider than a top width of the copper pillar.
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It would have been obvious to one of ordinary skill in the art to modify Li with C. Lin such that the copper pillar which is a part of the overall semiconductor structure described by C. Lin comprises a middle portion which gradually increases along a direction from the bottom of the copper pillar to the top, as described by Li, and an upper portion in which the width of the copper pillar is uniform, as described by C. Lin. A person having ordinary skill in the art would be motivated to do this, for example, to maintain a large surface area of contact between the top of the metal pillar and a secondary structure to which the substrate is bonded in order to reduce the stress applied to that secondary structure.
References Considered but not Cited
Chuang (US-20220344298-A1) – 90% or more (111) copper orientation in silver for low temp bonding.
Chen (US-20140090880-A1) – Electrical connect structure comprising 50% (111) oriented nanotwinned copper.
Katagiri (WO-2014142075-A1) – Pillar structure having a gradually increasing width from bottom to top.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to GABRIEL S MINNEY whose telephone number is (571)272-9688. The examiner can normally be reached Monday Friday, 8:30 a.m. 5 p.m. ET.
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/G.S.M./Examiner, Art Unit 2897
/JACOB Y CHOI/Supervisory Patent Examiner, Art Unit 2897