# US 7,610,678 B2 · Heat transfer sheet, heat transfer structural body and manufacturing method of the heat transfer structural body > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,610,678 B2 - Document ID: US7610678B2 - Status: Granted - Kind: B2 - Application number: 11/012,147 - Filed: 2004-12-16 - Published: 2006-02-23 - Granted: 2009-11-03 - Earliest claimed: 2004-08-19 - Assignees: Fujitsu Limited - Inventors: Hideshi Tokuhira; Hiroaki Date; Hiroki Uchida; Minoru Ishinabe - Web page: https://patentgrep.com/patent/US7610678B2 ## CPC - H10W 40/77: Auxiliary members characterised by their shape - H10W 40/251: {Organics} - H10W 40/257: {having a heterogeneous or anisotropic structure, e.g. powder or fibres in a matrix, wire mesh or porous structures (H10W40/254, H10W40/251 take precedence)} - H10W 40/70: Fillings or auxiliary members in containers or in encapsulations for thermal protection or control - H10W 72/30: Die-attach connectors - H10W 72/07331: {Connecting techniques} - H10W 72/325: {Die-attach connectors having a filler embedded in a matrix} - H10W 72/352: {comprising metals or metalloids, e.g. solders} - H10W 72/354: {comprising polymers} - H10W 72/877: {Bump connectors and die-attach connectors} - 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 90/726: {between a chip and a stacked lead frame, conducting package substrate or heat sink} - H10W 90/734: {between a chip and a stacked insulating package substrate, interposer or RDL} - Y10S 165/905: Materials of manufacture - Y10T 29/4935: Heat exchanger or boiler making - H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10 - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A pattern is formed with an insulative resin on a bonding face of a silicon chip, which is a heat generating element, and a pattern is formed with the insulative resin on a bonding face of a heat sink, which is a heat dissipating element, in alignment with the insulative resin parts formed on the silicon chip. The silicon chip and the heat sink are bonded to each other via a heat transfer sheet. The silicon chip and the heat sink are bonded to each other by a metal to form metal connection portions in a region where no insulative resin parts are formed, while the silicon ship and the heat sink are bonded to each other by a resin to form resin connection portions in a region where the insulative resin parts are formed. ## Claims ### Claim 1 A heat transfer sheet provided between a heat generating element and a heat dissipating element to transfer heat from the heat generating element to the heat dissipating element, the heat transfer sheet comprising: insulative resin films in which patterns corresponding to each other are formed; resin connection portions arranged corresponding to the patterns of the insulative resin films; and metal connection portions provided in regions exclusive of the insulative resin films, wherein the heat transfer sheet has plural regions having respective metal content ratios different from one another, and the insulative resin films are located in an area free of the metal connection portions. ### Claim 2 (depends on 1) The heat transfer sheet of claim 1, wherein shapes of the plural regions are the same as those of a heat spot region and regions other than the heat spot region. ### Claim 3 (depends on 1) The heat transfer sheet of claim 1, wherein the metal connection portions include a first kind of metal having a melting point of 200° C. or less and a second kind of metal higher in thermal conductivity than the first kind of metal. ### Claim 4 (depends on 3) The heat transfer sheet of claim 3, wherein the first kind of metal is a metal selected from the group consisting of alloys of Sn—Si, In—Sn—Bi, In—Bi, In—Sn and Pb—Sn, and In. ### Claim 5 (depends on 3) The heat transfer sheet of claim 3, wherein the second kind of metal is a metal selected from the group consisting of Au, Ag, Cu, Sn and Al. ### Claim 6 A heat transfer structural body comprising: a heat generating element; a heat dissipating element; and a heat transfer sheet provided between the heat generating element and the heat dissipating element to transfer heat from the heat generating element to the heat dissipating element, wherein the heat transfer sheet comprises insulative resin films in which patterns corresponding to each other are formed; resin connection portions arranged corresponding to the patterns of the insulative resin films; and metal connection portions provided in regions exclusive of the insulative resin films, and wherein the heat transfer sheet has plural regions having respective metal content ratios different from one another, and the insulative resin films are located in an area free of the metal connection portions. ### Claim 7 A heat transfer structural body comprising: a heat generating element; a heat dissipating element; and a heat transfer sheet provided between the heat generating element and the heat dissipating element to transfer heat from the heat generating element to the heat dissipating element, wherein the heat transfer sheet comprises insulative resin films in which patterns corresponding to each other are formed; resin connection portions arranged corresponding to the patterns of the insulative resin films; and metal connection portions provided in regions exclusive of the insulative resin films, wherein the heat transfer sheet has plural regions having respective metal content ratios different from one another, and the insulative resin films are located in an area free of the metal connection portions, and wherein the heat generating element has plural regions having respective temperatures different from one another, and a region of the heat generating element having a higher temperature corresponds to a region of the heat transfer sheet having a higher metal content. ### Claim 8 A heat transfer structural body comprising: a heat generating element; a heat dissipating element; and a heat transfer sheet provided between the heat generating element and the heat dissipating element to transfer heat from the heat generating element to the heat dissipating element, wherein the heat transfer sheet comprises insulative resin films in which patterns corresponding to each other are formed; resin connection portions arranged corresponding to the patterns of the insulative resin films; and metal connection portions provided in regions exclusive of the insulative resin films, wherein the heat transfer sheet has plural regions having respective metal content ratios different from one another, wherein the insulative resin films are located in an area free of the metal connection portions, and wherein the heat generating element has plural regions having respective temperatures different from one another, and a region of the heat generating element having a lower temperature corresponds to a region of the heat transfer sheet having a lower metal content. ### Claim 9 (depends on 6) The heat transfer structural body of claim 6, wherein the metal connection portions include a first kind of metal having a melting point of 200° C. or less and a second kind of metal higher in thermal conductivity than the first kind of metal. ### Claim 10 (depends on 9) The heat transfer structural body of claim 9, wherein the first kind of metal is a metal selected from the group consisting of alloys of Sn—Bi, In—Sn—Bi, In—Bi, In—Sn and Pb—Sn, and In. ### Claim 11 (depends on 9) The heat transfer structural body of claim 9, wherein the second kind of metal is a metal selected from the group consisting of Au, Ag, Cu, Sn and Al. ### Claim 12 A method for manufacturing a heat transfer structural body comprising a heat generating element, a heat dissipating element, and a heat transfer sheet bonded between the heat generating element and the heat dissipating element to thereby transfer heat from the heat generating element to the heat dissipating element, the method comprising the steps of: forming patterns with an insulative resin on respective bonding surfaces of the heat generating element and the heat dissipating element; applying a mixed material of a metal and a resin onto the respective bonding surfaces of the heat generating element and/or the heat dissipating element on which the pattern has been formed with the insulative resin by arranging resin connection portions corresponding to the patterns of the insulative resin; and providing metal connection portions in regions exclusive of the insulative resin; and aligning the patterned insulative resin formed on the heat generating element with the corresponding patterned insulative resin formed on the heat dissipating element to thereby heat-bond the heat generating element, the mixed material and the heat dissipating element; wherein said regions have respective metal content ratios different from one another, and the insulative resin are located in an area free of the metal connection portions. ### Claim 13 (depends on 12) The method of claim 12, wherein an area coverage in percent in a pattern with the insulative resin is 60% or less of the total area of each of the bonding surfaces of the heat generating element and the heat dissipating element. ### Claim 14 (depends on 12) The method of claim 12, wherein the mixed material is obtained by dispersing a metal filler having a thermal conductivity into a thermosetting resin. ### Claim 15 (depends on 14) The method of claim 14, wherein the metal filler includes a first kind of metal filler having a melting point of 200° C. or less and a second kind of metal filler higher in thermal conductivity than the first kind of metal filler. ### Claim 16 (depends on 15) The method of claim 15, wherein the first kind of metal filler is a filler of metal selected from the group consisting of alloys of Sn—Bi, In—Sn—Bi, In—Bi, In—Sn and Pb—Sn, and In. ### Claim 17 (depends on 15) The method of claim 15, wherein the second kind of metal filler is a filler of metal selected from the group consisting of Au, Ag, Cu, Sn and Al.