# US 11,908,820 B2 · Dual solder methodologies for ultrahigh density first level interconnections > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,908,820 B2 - Document ID: US11908820B2 - Status: Granted - Kind: B2 - Application number: 17/668,246 - Filed: 2022-02-09 - Published: 2022-05-26 - Granted: 2024-02-20 - Earliest claimed: 2017-12-18 - Assignees: Intel Corporation - Applicants: Intel Corporation - Inventors: Chandramouleeswaran Subramani - Web page: https://patentgrep.com/patent/US11908820B2 ## CPC - G06F 13/102: {where the program performs an interfacing function, e.g. device driver (G06F13/105 takes precedence; contention policies within device drivers G06F9/4881; scheduling within device drivers G06F9/52)} - H10W 74/131: {the semiconductor body being only partially enclosed} - H10W 90/00: Package configurations - H10W 72/01235: {by plating, e.g. electroless plating or electroplating} - H10W 72/01251: {Changing the shapes of bumps} - H10W 72/01257: {by reflowing} - H10W 72/072: {of bump connectors} - H10W 72/07221: {Aligning} - H10W 72/07232: {Compression bonding, e.g. thermocompression bonding} - H10W 72/07236: {Soldering or alloying} - H10W 72/07255: {changes in materials} - H10W 72/073: {of die-attach connectors} - H10W 72/222: {Multilayered bumps, e.g. a coating on top and side surfaces of a bump core} - H10W 72/241: {Dispositions, e.g. layouts} - H10W 72/244: {relative to underlying supporting features, e.g. bond pads, RDLs or vias} - H10W 72/252: {comprising solid metals or solid metalloids, e.g. PbSn, Ag or Cu} - H10W 72/2528: {Intermetallic compounds} - H10W 72/29: Bond pads specially adapted therefor - H10W 72/354: {comprising polymers} - H10W 72/952: {comprising metals or metalloids, e.g. PbSn, Ag or Cu} - H10W 74/012: {of encapsulations on active surfaces of flip-chip devices, e.g. forming underfills} - H10W 74/15: on active surfaces of flip-chip devices, e.g. underfills - H10W 90/724: {between a chip and a stacked insulating package substrate, interposer or RDL} - H10W 90/725: {between a chip and a laterally-adjacent insulating package substrate, interposer or RDL} - H10W 90/734: {between a chip and a stacked insulating package substrate, interposer or RDL} - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10 ## Abstract An apparatus, comprising an integrated circuit (IC) package having at least one solder bond pad, a die having at least one solder bond pad, wherein the die is bonded to the IC package by at least one solder joint between the at least one solder bond pad of the die, and the at least one solder bond pad of the IC package, and an underfill material between the IC package and the die, wherein the at least one solder joint is embedded in the underfill material, and wherein the at least one solder joint comprises a first metallurgy and a second metallurgy. ## Claims ### Claim 1 A method, comprising: providing, between a first bond pad of a die and a second bond pad of an integrated circuit (IC) package, a first structure comprising a first solder metallurgy and, between the first structure and one of the first bond pad or the second bond pad, a second structure comprising a second solder metallurgy; reflowing, prior to underfill, the first structure at a first temperature below a liquidus temperature of the second structure to form a first solder joint between the first bond pad and the second bond pad; forming an underfill material between the die and the IC package and adjacent the first solder joint; and reflowing, after said forming the underfill material, the first and second structures at a second temperature above the liquidus temperature of the second structure to form a second solder joint between the first bond pad and the second bond pad. ### Claim 2 (depends on 1) The method of claim 1, wherein the first structure is between the first bond pad and the second structure. ### Claim 3 (depends on 2) The method of claim 2, further comprising: forming the second structure on the second bond pad by depositing a bump comprising the first second solder metallurgy and compressing the bump to form the second structure. ### Claim 4 (depends on 3) The method of claim 3, further comprising: forming the first structure on the first bond pad. ### Claim 5 (depends on 2) The method of claim 2, wherein the first structure is on the first bond pad, the second structure is on the second bond pad, and the first solder joint is formed at an interface between the first and second structures. ### Claim 6 (depends on 1) The method of claim 1, wherein the second structure is between the first bond pad and the first structure. ### Claim 7 (depends on 6) The method of claim 6, further comprising: forming the second structure on the first bond pad; and forming the first structure on the second structure. ### Claim 8 (depends on 7) The method of claim 7, wherein the first solder joint is formed at an interface between the first structure and the second bond pad. ### Claim 9 (depends on 1) The method of claim 1, wherein the first structure has a volume less than a volume of the second structure. ### Claim 10 (depends on 1) The method of claim 1, wherein the first structure comprises one or more of tin, silver, zinc, copper, bismuth and indium and the second structure comprises one or more of gold, aluminum, germanium, zinc, tin, bismuth, or indium. ### Claim 11 (depends on 1) The method of claim 1, wherein the first structure comprises not less than 89% tin and the second structure comprises not less than 80% gold or not less than 95% zinc. ### Claim 12 (depends on 11) The method of claim 11, wherein the first structure further comprises silver, copper, zinc or bismuth. ### Claim 13 A method, comprising: providing a first structure comprising a first solder metallurgy on a first bond pad of a die; providing a second structure comprising a second solder metallurgy on a second bond pad of an integrated circuit (IC) package; contacting the first structure and the second structure; reflowing, prior to underfill, the first structure at a first temperature below a liquidus temperature of the second structure to form a first solder joint between the first structure and the second structure; forming an underfill material between the die and the IC package and adjacent the first solder joint; and reflowing, after said forming the underfill material, the first and second structures at a second temperature above the liquidus temperature of the second structure to form a second solder joint between the first bond pad and the second bond pad. ### Claim 14 (depends on 13) The method of claim 13, wherein the first structure has a volume less than a volume of the second structure. ### Claim 15 (depends on 13) The method of claim 13, wherein the first structure comprises one or more of tin, silver, zinc, copper, bismuth and indium and the second structure comprises one or more of gold, aluminum, germanium, zinc, tin, bismuth, or indium. ### Claim 16 (depends on 13) The method of claim 13, wherein the first structure comprises not less than 89% tin and the second structure comprises not less than 80% gold or not less than 95% zinc. ### Claim 17 A method, comprising: providing a first structure comprising a first solder metallurgy on a first bond pad of a die; providing a second structure comprising a second solder metallurgy on the first structure; contacting the second structure to a second bond pad of an integrated circuit (IC) package; reflowing, prior to underfill, the second structure at a first temperature below a liquidus temperature of the first structure to form a first solder joint between the second structure and the second bond pad; forming an underfill material between the die and the IC package and adjacent the first solder joint; and reflowing, after said forming the underfill material, the first and second structures at a second temperature above the liquidus temperature of the first structure to form a second solder joint between the first bond pad and the second bond pad. ### Claim 18 (depends on 17) The method of claim 17, wherein the first structure has a volume less than a volume of the second structure. ### Claim 19 (depends on 17) The method of claim 17, wherein the first structure comprises one or more of tin, silver, zinc, copper, bismuth and indium and the second structure comprises one or more of gold, aluminum, germanium, zinc, tin, bismuth, or indium. ### Claim 20 (depends on 17) The method of claim 17, wherein the first structure comprises not less than 89% tin and the second structure comprises not less than 80% gold or not less than 95% zinc.