# US 2014/0151096 A1 · Low temperature/high temperature solder hybrid solder interconnects > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0151096 A1 - Document ID: US20140151096A1 - Status: Published application - Kind: A1 - Application number: 13/693,403 - Filed: 2012-12-04 - Published: 2014-06-05 - Earliest claimed: 2012-12-04 - Inventors: Hongjin Jiang; Patrick N. Stover; Arun Kumar C. Nallani; Rajen Sidhu; Ameya Limaye - Web page: https://patentgrep.com/patent/US20140151096A1 ## CPC - H05K 3/3436: {having an array of bottom contacts, e.g. pad grid array or ball grid array components} - H10W 72/20: Bump connectors, e.g. solder bumps or copper pillars; Dummy bumps; Thermal bumps - H10W 90/701: {characterised by the relative positions of pads or connectors relative to package parts} - H05K 3/346: Solder materials or compositions specially adapted therefor - H05K 3/3494: Heating processes for reflow soldering - H05K 2203/041: Solder preforms in the shape of solder balls - H10W 72/07253: {changes in shapes} - H10W 72/234: {Cross-sectional shape, i.e. in side view} - H10W 72/245: {of outermost layers of multilayered bumps, e.g. bump coating being only on a part of a bump core} - H10W 72/252: {comprising solid metals or solid metalloids, e.g. PbSn, Ag or Cu} - H10W 72/354: {comprising polymers} - 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 90/734: {between a chip and a stacked insulating package substrate, interposer or RDL} - Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product - Y10T 29/49144: by metal fusion - H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS - H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10 - Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract Embodiments of the present description relate to the field of fabricating microelectronic structures, wherein a microelectronic package may be attached to a microelectronic substrate with a hybrid solder interconnect. The hybrid solder interconnect may comprise a homogenous mixture of low temperature solder and a high temperature solder extending between at least one bond pad on a microelectronic package and at least one bond pad on a microelectronic substrate, wherein the relatively low reflow temperature used during the formation of the hybrid solder interconnect may prevent solder defects caused by warpage which may occur during the attachment of the microelectronic package to the microelectronic substrate. ## Claims ### Claim 1 A hybrid solder structure, comprising: a bond pad; a high temperature solder ball; and a low temperature solder material disposed between the bond pad and the high temperature solder ball. ### Claim 2 (depends on 1) The hybrid structure of claim 1, wherein the high temperature solder ball comprises a tin/silver/copper alloy. ### Claim 3 (depends on 2) The microelectronic structure of claim 2, wherein the tin/silver/copper alloy comprises an alloy of about 95.5% tin, about 4% silver, and about 0.5% copper. ### Claim 4 (depends on 1) The microelectronic structure of claim 1, wherein the low temperature solder material comprises a tin/bismuth/copper/nickel alloy. ### Claim 5 (depends on 1) The microelectronic structure of claim 1, wherein the low temperature solder material comprises a tin/bismuth/copper/antimony alloy. ### Claim 6 (depends on 1) The microelectronic structure of claim 1, wherein the bond pad is disposed on an attachment surface of the microelectronic package. ### Claim 7 A hybrid solder structure, comprising: a bond pad; a high temperature solder ball attached to the bond pad; and a low temperature solder material disposed on at least a portion of the high temperature solder ball not attached to the bond pad. ### Claim 8 (depends on 7) The hybrid structure of claim 7, wherein the high temperature solder ball comprises a tin/silver/copper alloy. ### Claim 9 (depends on 8) The microelectronic structure of claim 8, wherein the tin/silver/copper alloy comprises an alloy of about 95.5% tin, about 4% silver, and about 0.5% copper. ### Claim 10 (depends on 7) The microelectronic structure of claim 7, wherein the low temperature solder material comprises a tin/bismuth/copper/nickel alloy. ### Claim 11 (depends on 7) The microelectronic structure of claim 7, wherein the low temperature solder material comprises a tin/bismuth/copper/antimony alloy. ### Claim 12 (depends on 7) The microelectronic structure of claim 7, wherein the bond pad is disposed on an attachment surface of the microelectronic package. ### Claim 13 A method of fabricating a microelectronic structure, comprising: forming a microelectronic package having at least one high temperature solder ball attached to at least one microelectronic package bond pad; disposing a low temperature solder material on the at least one high temperature solder ball; forming a microelectronic substrate having at least one microelectronic substrate bond pad; and attaching the microelectronic package to the microelectronic substrate by reflowing the at least one high temperature solder ball to form a hybrid solder interconnect extending between the at least one microelectronic package bond pad and the at least one microelectronic substrate bond pad. ### Claim 14 (depends on 13) The method of claim 13, further including reflowing the low temperature solder material to substantially coat the high temperature solder ball prior to attaching the microelectronic package to the microelectronic substrate. ### Claim 15 (depends on 13) The method of claim 13, wherein forming the microelectronic package having at least one high temperature solder ball attached to at least one microelectronic package bond pad comprises forming the microelectronic package having at least one high temperature solder ball comprising a tin/silver/copper alloy, attached to at least one microelectronic package bond pad. ### Claim 16 (depends on 15) The method of claim 15, wherein forming the microelectronic package having at least one high temperature solder ball, comprising a tin/silver/copper alloy, attached to at least one microelectronic package bond pad comprises forming the microelectronic package having at least one high temperature solder ball, comprising an alloy of about 95.5% tin, about 4% silver, and about 0.5% copper, attached to at least one microelectronic package bond pad. ### Claim 17 (depends on 13) The method of claim 13, wherein disposing a low temperature solder material on the at least one high temperature solder ball comprises disposing a low temperature solder material, comprising a tin/copper/nickel alloy, on the at least one high temperature solder ball. ### Claim 18 (depends on 13) The method of claim 13, wherein disposing a low temperature solder material on the at least one high temperature solder ball comprises disposing a low temperature solder material, comprising a tin/copper/antimony alloy, on the at least one high temperature solder ball. ### Claim 19 A method of fabricating a microelectronic structure, comprising: forming a microelectronic package having at least one high temperature solder ball attached to at least one microelectronic package bond pad; forming a microelectronic substrate having at least one microelectronic substrate bond pad; disposing a low temperature solder material on the at least one microelectronic substrate bond pad; and attaching the microelectronic package to the microelectronic substrate by reflowing the at least one high temperature solder ball to form a hybrid solder interconnect extending between the at least one microelectronic package bond pad and the at least one microelectronic substrate bond pad. ### Claim 20 (depends on 19) The method of claim 19, wherein forming the microelectronic package having at least one high temperature solder ball attached to at least one microelectronic package bond pad comprises forming the microelectronic package having at least one high temperature solder ball comprising a tin/silver/copper alloy, attached to at least one microelectronic package bond pad. ### Claim 21 (depends on 20) The method of claim 20, wherein forming the microelectronic package having at least one high temperature solder ball, comprising a tin/silver/copper alloy, attached to at least one microelectronic package bond pad comprises forming the microelectronic package having at least one high temperature solder ball, comprising an alloy of about 95.5% tin, about 4% silver, and about 0.5% copper, attached to at least one microelectronic package bond pad. ### Claim 22 (depends on 19) The method of claim 19, wherein disposing a low temperature solder material on the at least one microelectronic substrate bond pad comprises disposing a low temperature solder material, comprising a tin/bismuth/copper/nickel alloy, on the at least one microelectronic substrate bond pad. ### Claim 23 (depends on 13) The method of claim 13, wherein disposing a low temperature solder material on the at least one microelectronic substrate bond pad comprises disposing a low temperature solder material, comprising a tin/bismuth/copper/antimony alloy, on the at least one microelectronic substrate bond pad. ### Claim 24 A method of fabricating a microelectronic structure, comprising: forming a microelectronic package having at least one microelectronic package bond pad; disposing a low temperature solder material on the at least one microelectronic package bond pad; attaching at least one high temperature solder ball to the low temperature solder material and then reflowing to form at least one hybrid solder structure; forming a microelectronic substrate having at least one microelectronic substrate bond pad; and attaching the microelectronic package to the microelectronic substrate by reflowing the at least one hybrid solder structure to form a hybrid solder interconnect extending between the at least one microelectronic package bond pad and the at least one microelectronic substrate bond pad. ### Claim 25 (depends on 24) The method of claim 24, wherein attaching at least one high temperature solder ball to the low temperature solder material comprises attaching at least one high temperature solder ball, comprising a tin/silver/copper alloy, to the low temperature solder material. ### Claim 26 (depends on 25) The method of claim 25, wherein attaching at least one high temperature solder ball, comprising a tin/silver/copper alloy, to the low temperature solder material comprises attaching at least one high temperature solder ball, comprising an alloy of about 95.5% tin, about 4% silver, and about 0.5% copper, to the low temperature solder material. ### Claim 27 (depends on 24) The method of claim 24, wherein disposing a low temperature solder material on the at least one microelectronic package bond pad comprises disposing a low temperature solder material, comprising a tin/bismuth/copper/nickel alloy, on the at least one microelectronic package bond pad. ### Claim 28 (depends on 24) The method of claim 24, wherein disposing a low temperature solder material on the at least one microelectronic package bond pad comprises disposing a low temperature solder material, comprising a tin/bismuth/copper/antimony alloy, on the at least one microelectronic package bond pad. ### Claim 29 (depends on 24) The method of claim 24, wherein attaching at least one high temperature solder ball to the low temperature solder material and then reflowing to form at least one hybrid solder structure comprises attaching at least one high temperature solder ball to the low temperature solder material and then reflowing to form at least one homogenized hybrid solder structure.