# US 5,700,562 A · Flexible printed circuit and manufacturing method therefor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,700,562 A - Document ID: US5700562A - Status: Granted - Kind: A - Application number: 08/701,954 - Filed: 1996-08-23 - Granted: 1997-12-23 - Earliest claimed: 1995-08-24 - Assignees: Nitto Denko Corporation - Inventors: Toshihiko Sugimoto; Chiharu Miyaake; Yousuke Miki - Web page: https://patentgrep.com/patent/US5700562A ## CPC - B32B 15/08: of synthetic resin - B32B 7/027: Thermal properties - B32B 7/03: with respect to the orientation of features (direction of fibres or filaments B32B5/12) - B32B 7/12: using interposed adhesives or interposed materials with bonding properties - B32B 38/1825: {characterised by the control or constructional features of devices for tensioning, stretching or registration} - H05K 1/0271: {Arrangements for reducing stress or warp in rigid printed circuit boards, e.g. caused by loads, vibrations or differences in thermal expansion} - H05K 3/281: {by means of a preformed insulating foil (H05K3/284 takes precedence)} - B29C 55/00: Shaping by stretching, e.g. drawing through a die; Apparatus therefor (B29C61/08 takes precedence) - B29K 2995/0096: Dimensional stability - B32B 2038/0028: {Stretching, elongating} - B32B 2457/00: Electrical equipment - B32B 2457/08: PCBs, i.e. printed circuit boards - H05K 1/0266: {Marks, test patterns or identification means} - H05K 1/0393: {Flexible materials (H05K1/038 takes precedence; specific organic compositions are classified in H05K1/0313 and subgroups)} - H05K 3/0052: {Depaneling, i.e. dividing a panel into circuit boards; Working of the edges of circuit boards} - H05K 3/386: {by the use of an organic polymeric bonding layer, e.g. adhesive} - H05K 3/4611: {by laminating two or more circuit boards (H05K3/4652 takes precedence)} - H05K 3/4635: {laminating flexible circuit boards using additional insulating adhesive materials between the boards} - H05K 2201/068: wherein the coefficient of thermal expansion is important - H05K 2203/0156: Temporary polymeric carrier or foil, e.g. for processing or transferring - H05K 2203/0271: Mechanical force other than pressure, e.g. shearing or pulling - Y10S 428/901: Printed circuit - Y10T 428/24917: including metal layer - Y10T 428/254: Polymeric or resinous material - B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM - H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS - B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00) - B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A composite sheet comprises a first resin film; and a second resin film laminated on the first resin film; wherein two ellipses of coefficient of linear expansion are created on polar coordinates in corresponding parts of the first and second resin films by a predetermined method and the two ellipse are overlapped so as to match in the center point and coordinate axes X and Y, and the maximum value of a linear expansion coefficient difference between the two resin films is equal to or less than a predetermined value. ## Claims ### Claim 1 A composite sheet comprising: a first resin film having a first linear expansion coefficient ellipse defined by a pair of first polar coordinate axes and a first base point located at an intersection of the first axes; and a second resin film having a second linear expansion coefficient ellipse defined by a second pair of polar coordinate axes and a second base point located at an intersection of the second axes; the second resin film being laminated on the first resin film such that the second ellipse overlaps the first ellipse with the first axes coinciding with the second axes and the first base point coinciding with the second base point; wherein the first and second linear expansion coefficient ellipses are a set of distances from the first and second base points, respectively, representing magnitudes of linear expansion coefficients of the first and second resin films, respectively, in directions having a measurement angle .theta. with respect to one of the first axes and the corresponding one of the second axes, respectively; and wherein a maximum difference between a linear expansion coefficient having the measurement angle .theta. of the first resin film and a linear expansion coefficient having the measurement angle .theta. of the second resin film is equal to or less than 1.4.times.10.sup.-5 (1/.degree. C.). ### Claim 2 (depends on 1) The composite sheet according to claim 1, wherein the first and second resin films are laminated on each other with the same surfaces thereof facing each other. ### Claim 3 (depends on 1) The composite sheet according to claim 1, wherein the composite sheet is a flexible printed circuit. ### Claim 4 (depends on 3) The composite sheet according to claim 3, wherein a metal electric circuit is formed between the first and second resin films and a product of thickness and tensile modulus of the metal electric circuit is 500 kg/mm or less. ### Claim 5 (depends on 1) The composite sheet according to claim 1, wherein a reinforcing plastic film is stuck on one side of the composite sheet and has a third linear expansion coefficient ellipse defined by a pair of third polar coordinate axes and a third base point located at the intersection of the third axes; and wherein a maximum difference between a linear expansion coefficient having the measurement angle .theta. of the reinforcing plastic film and a linear expansion coefficient having the measurement angle .theta. of one of the first and second resin films positioned on a side on which the reinforcing plastic film is not stuck is equal to or less than 1.4.times.10.sup.-5 (1/.degree. C.). ### Claim 6 (depends on 1) The composite sheet according to claim 1, wherein one or more other resin films are sandwiched between the first and second resin films. ### Claim 7 (depends on 1) The composite sheet according to claim 1, wherein the first and second resin film are laminated via an adhesive layer. ### Claim 8 (depends on 7) The composite sheet according to claim 7, wherein the first and second resin films stacked via the adhesive layer are temporarily crimped by a roll laminate method in stacked relation and then pressurized under gas pressure in an autoclave and crimped. ### Claim 9 A composite sheet comprising: a first resin film having a first linear expansion coefficient ellipse defined by a pair of first polar coordinate axes and a first base point located at an intersection of the first axes; and a second resin film having a second linear expansion coefficient ellipse defined by a second pair of polar coordinate axes and a second base point located at an intersection of the second axes; the second resin film being laminated on the first resin film such that the second ellipse overlaps the first ellipse with the first axes coinciding with the second axes and the first base point coinciding with the second base point; wherein the first and second linear expansion coefficient ellipses are a set of distances from the first and second base points, respectively, representing magnitudes of linear expansion coefficients of the first and second resin films, respectively, in directions having a measurement angle .theta. with respect to one of the first axes and the corresponding one of the second axes, respectively: and wherein a total area of portions where the first and second ellipses do not overlap is equal to or less than 6.5.times.10.sup.-10 ((1/.degree. C.).times.(1/.degree. C.). ### Claim 10 (depends on 9) The composite sheet according to claim 9, wherein the first and second resin films are laminated on each other with the same surfaces thereof facing each other. ### Claim 11 (depends on 9) The composite sheet according to claim 9, wherein the composite sheet is a flexible printed circuit. ### Claim 12 (depends on 11) The composite sheet according to claim 11, wherein a metal electric circuit is formed between the first and second resin films and a product of thickness and tensile modulus of the metal electric circuit is 500 kg/mm or less. ### Claim 13 (depends on 1) The composite sheet according to claim 1, wherein a reinforcing plastic film is stuck on one side of the composite sheet and has a third linear expansion coefficient ellipse defined by a pair of third polar coordinate axes and a third base point located at the intersection of the third axes; and wherein a total nonoverlapping area of the third ellipse and the ellipse of one of the first and second resin films positioned on a side on which the reinforcing plastic film is not stuck is equal to or less than 6.5.times.10.sup.-10 (1/.degree. C.).times.(1/.degree. C.)). ### Claim 14 (depends on 9) The composite sheet according to claim 9, wherein one or more other resin films are sandwiched between the first and second resin films. ### Claim 15 (depends on 9) The composite sheet according to claim 9, wherein the first and second resin film are laminated via an adhesive layer. ### Claim 16 (depends on 15) The composite sheet according to claim 15, wherein the first and second resin films stacked via the adhesive layer are temporarily crimped by a roll laminate method in stacked relation and then pressurized under gas pressure in an autoclave and crimped. ### Claim 17 A composite sheet comprising: a first resin film having a first ultrasonic propagation velocity ellipse defined by a pair of first polar coordinate axes, having a crystal orientation main axis in a long-axis direction and a crystal orientation subaxis in a short-axis direction, and a first base point located at an intersection of the first axes; and a second resin film having a second ultrasonic propagation velocity ellipse defined by a second pair of polar coordinate axes, having a crystal orientation main axis in a long-axis direction and a crystal orientation subaxis in a short-axis direction, and a second base point located at an intersection of the second axes; the second resin film being laminated on the first resin film such that the second ellipse overlaps the first ellipse with the first axes coinciding with the second axes and the first base point coinciding with the second base point; wherein the first and second ultrasonic propagation velocity ellipses are a set of distances from the first and second base points, respectively, representing magnitudes of ultrasonic propagation velocities of the first and second resin films, respectively, in directions having a measurement angle .theta. with respect to one of the first axes and the corresponding one of the second axes, respectively; and wherein a shift angle difference between crystal orientation main axes of the ellipses (.DELTA..theta.) is within 30 degrees. ### Claim 18 (depends on 17) The composite sheet according to claim 17, wherein the first and second resin films are laminated on each other with the same surfaces thereof facing each other. ### Claim 19 (depends on 17) The composite sheet according to claim 17, wherein the composite sheet is a flexible printed circuit. ### Claim 20 (depends on 19) The composite sheet according to claim 19, wherein a metal electric circuit is formed between the first and second resin films and a product of thickness and tensile modulus of the metal electric circuit is 500 kg/mm or less. ### Claim 21 (depends on 1) The composite sheet according to claim 1, wherein a reinforcing plastic film is stuck on one side of the composite sheet and has a third ultrasonic propagation velocity ellipse defined by a pair of third polar coordinate axes, having a crystal orientation main axis in a long-axis direction and a crystal orientation subaxis in a short-axis direction, and a third base point located at the intersection of the third axes; and wherein a shift angle difference between a crystal orientation main axis of the third ellipse and the ellipse of one of the first and second resin films positioned on a side on which the reinforcing plastic film is not stuck is within 30 degrees. ### Claim 22 (depends on 17) The composite sheet according to claim 17, wherein one or more other resin films are sandwiched between the first and second resin films. ### Claim 23 (depends on 17) The composite sheet according to claim 17, wherein the first and second resin films are laminated via an adhesive layer. ### Claim 24 (depends on 23) The composite sheet according to claim 23, wherein the first and second resin films stacked via the adhesive layer are temporarily crimped by a roll laminate method in stacked relation and then pressurized under gas pressure in an autoclave and crimped. ### Claim 25 (depends on 1) The composite sheet according to claim 1, wherein one axis of each of the first and second axes is in a machine direction of film stretch and the other axis of each of the first and second axes is in a transverse direction of film stretch. ### Claim 26 (depends on 1) The composite sheet according to claim 1, wherein the composite sheet is a flexible printed circuit, and one axis of each of the first and second axes is in a machine direction of film stretch and the other axis of each of the first and second axes is in a transverse direction of film stretch. ### Claim 27 (depends on 9) The composite sheet according to claim 9 wherein one axis of each of the first and second axes is in a machine direction of film stretch and the other axis of each of the first and second axes is in a transverse direction of film stretch. ### Claim 28 (depends on 9) The composite sheet according to claim 9, wherein the composite sheet is a flexible printed circuit, and one axis of each of the first and second axes is in a machine direction of film stretch and the other axis of each of the first and second axes is in a transverse direction of film stretch. ### Claim 29 (depends on 17) The composite sheet according to claim 17, wherein one axis of each of the first and second axes is in a machine direction of film stretch and the other axis of each of the first and second axes is in a transverse direction of film stretch. ### Claim 30 (depends on 17) The composite sheet according to claim 17, wherein the composite sheet is a flexible printed circuit, and one axis of each of the first and second axes is in a machine direction of film stretch and the other axis of each of the first and second axes is in a transverse direction of film stretch. ### Claim 31 (depends on 1) The composite sheet according to claim 1, wherein the first and second resin films are made of the same material. ### Claim 32 (depends on 9) The composite sheet according to claim 9, wherein the first and second resin films are made of the same material. ### Claim 33 (depends on 17) The composite sheet according to claim 17, wherein the first and second resin films are made of the same material.