# US 7,743,492 B2 · Method for forming cast flexible substrate and resultant substrate and electronic device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,743,492 B2 - Document ID: US7743492B2 - Status: Granted - Kind: B2 - Application number: 12/028,206 - Filed: 2008-02-08 - Published: 2009-08-13 - Granted: 2010-06-29 - Earliest claimed: 2008-02-08 - Assignees: Carestream Health, Inc. - Inventors: Roger Stanley Kerr; Timothy John Tredwell; Yongtaek Hong - Web page: https://patentgrep.com/patent/US7743492B2 ## CPC - H05K 3/0014: {Shaping of the substrate, e.g. by moulding} - H05K 3/007: {Manufacture or processing of a substrate for a printed circuit board supported by a temporary or sacrificial carrier (H05K1/187, H05K3/20 and H05K3/4682 take precedence)} - H05K 1/0346: {containing N} - H05K 1/0393: {Flexible materials (H05K1/038 takes precedence; specific organic compositions are classified in H05K1/0313 and subgroups)} - H05K 2201/09036: Recesses or grooves in insulating substrate - H05K 2201/09045: Locally raised area or protrusion of insulating substrate - H05K 2203/0108: Male die used for patterning, punching or transferring - H05K 2203/016: Temporary inorganic, non-metallic carrier, e.g. for processing or transferring - H05K 2203/0759: Forming a polymer layer by liquid coating, e.g. a non-metallic protective coating or an organic bonding layer - Y10T 29/49124: On flat or curved insulated base, e.g., printed circuit, etc. - Y10T 29/49126: Assembling bases - Y10T 29/4913: Assembling to base an electrical component, e.g., capacitor, etc. - Y10T 29/49158: with molding of insulated base - H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A method for forming an electronic device provides a casting master having a casting surface, and deposits a substrate material onto the casting surface to form a flexible substrate sheet of predetermined thickness, wherein the flexible substrate sheet has a circuit-side surface that is formed against the casting surface. The flexible substrate sheet is released from the master and secured against a carrier, with the circuit-side surface facing outward. An electronic device is then formed on the circuit-side surface. ## Claims ### Claim 1 A method for forming an electronic device comprising: forming a master having a casting surface; depositing a substrate material onto the casting surface to form a flexible substrate sheet of predetermined thickness, wherein the flexible substrate sheet has a circuit-side surface that is formed against the casting surface, and a back surface; releasing the flexible substrate sheet from the master; securing the flexible substrate sheet against a carrier, with the circuit-side surface facing outward; and forming the electronic device on the circuit-side surface of the flexible substrate sheet while the back surface of the flexible substrate sheet is secured against the carrier. ### Claim 2 (depends on 1) The method of claim 1 wherein the carrier is formed from glass. ### Claim 3 (depends on 1) The method of claim 1 wherein the casting surface of the master is featured with at least one indentation or protrusion. ### Claim 4 (depends on 1) The method of claim 1 wherein the substrate material is polyimide. ### Claim 5 (depends on 1) The method of claim 1 wherein the substrate material is plastic. ### Claim 6 (depends on 1) The method of claim 1 wherein the substrate material is metal. ### Claim 7 (depends on 1) The method of claim 1 wherein releasing the flexible substrate comprises cooling the master, the substrate, or both. ### Claim 8 (depends on 1) The method of claim 1 further comprising forming one or more patterns of material on the back surface prior to releasing the sheet from the master. ### Claim 9 (depends on 8) The method of claim 8 wherein the one or more patterns of material are taken from the group consisting of metals, semiconductors, and dielectrics. ### Claim 10 (depends on 8) The method of claim 8 further comprising forming one or more vias between the patterns of material formed on the back surface and the circuit-side surface. ### Claim 11 (depends on 1) The method of claim 1 wherein releasing the flexible substrate sheet comprises using a solvent. ### Claim 12 (depends on 1) The method of claim 1 wherein releasing the flexible substrate sheet comprises applying radiant energy to the substrate sheet or to the master. ### Claim 13 (depends on 1) The method of claim 1 further comprising curing the substrate material that is deposited onto the casting surface. ### Claim 14 (depends on 13) The method of claim 13 wherein curing comprises irradiating the substrate material with ultraviolet radiation. ### Claim 15 (depends on 1) The method of claim 1 wherein the predetermined thickness is less than 100 microns. ### Claim 16 (depends on 1) The method of claim 1 wherein the predetermined thickness is between about 50 and 100 microns. ### Claim 17 (depends on 1) The method of claim 1 wherein the predetermined thickness is between about 10 and 50 microns. ### Claim 18 (depends on 1) The method of claim 1 wherein depositing the substrate material comprises spin-coating. ### Claim 19 (depends on 1) The method of claim 1 wherein depositing the substrate material comprises printing the material onto the casting surface.