Method for forming cast flexible substrate and resultant substrate and electronic device

• US 7,743,492 B2
• Filed: 02/08/2008
• Issued: 06/29/2010
• Est. Priority Date: 02/08/2008
• Status: Active Grant

• Current Assignee: CareStream Health Incorporated
• Original Assignee: CareStream Health Incorporated
• Inventors: Tredwell, Timothy John, Hong, Yongtaek, Kerr, Roger Stanley
• Primary Examiner(s): Banks; Derris H
• Assistant Examiner(s): CARLEY, JEFFREY T.
• Application Number:
  US12/028,206
• Publication Number:
  US 20090199401A1
• Time in Patent Office: 872 Days
• Field of Search: 298/29, 298/30, 298/32, 257/E23.065, 257/E23.177, 438149-166, 174254-256, 174/258, 174/260, 164/2, 164/46, 164/47, 264/209, 264/309, 264/316, 264/336, 264/337
• US Class Current: 29/832
• CPC Class Codes: H05K 1/0346 containing N
• CPC Class Codes: H05K 1/0393 Flexible materials H05K1/038 takes precedence; specific organic compositions are classified in H05K1/0313 and subgroups
• CPC Class Codes: H05K 2201/09036 Recesses or grooves in insulating substrate
• CPC Class Codes: H05K 2201/09045 Locally raised area or protrusion of insulating substrate
• CPC Class Codes: H05K 2203/0108 Male die used for patterning, punching or transferring
• CPC Class Codes: H05K 2203/016 Temporary inorganic, non-metallic carrier, e.g. for processing or transferring
• CPC Class Codes: H05K 2203/0759 Forming a polymer layer by liquid coating, e.g. a non-metallic protective coating or an organic bonding layer
• CPC Class Codes: H05K 3/0014 Shaping of the substrate, e.g. by moulding
• CPC Class Codes: 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
• CPC Class Codes: Y10T 29/49124 On flat or curved insulated base, e.g., printed circuit, etc.
• CPC Class Codes: Y10T 29/49126 Assembling bases
• CPC Class Codes: Y10T 29/4913 Assembling to base an electrical component, e.g., capacitor, etc.
• CPC Class Codes: Y10T 29/49158 with molding of insulated base

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

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.

2. The method of claim 1 wherein the carrier is formed from glass.

3. The method of claim 1 wherein the casting surface of the master is featured with at least one indentation or protrusion.

4. The method of claim 1 wherein the substrate material is polyimide.

5. The method of claim 1 wherein the substrate material is plastic.

6. The method of claim 1 wherein the substrate material is metal.

7. The method of claim 1 wherein releasing the flexible substrate comprises cooling the master, the substrate, or both.

8. 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.

9. The method of claim 8 wherein the one or more patterns of material are taken from the group consisting of metals, semiconductors, and dielectrics.

10. 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.

11. The method of claim 1 wherein releasing the flexible substrate sheet comprises using a solvent.

12. The method of claim 1 wherein releasing the flexible substrate sheet comprises applying radiant energy to the substrate sheet or to the master.

13. The method of claim 1 further comprising curing the substrate material that is deposited onto the casting surface.

14. The method of claim 13 wherein curing comprises irradiating the substrate material with ultraviolet radiation.

15. The method of claim 1 wherein the predetermined thickness is less than 100 microns.

16. The method of claim 1 wherein the predetermined thickness is between about 50 and 100 microns.

17. The method of claim 1 wherein the predetermined thickness is between about 10 and 50 microns.

18. The method of claim 1 wherein depositing the substrate material comprises spin-coating.

19. The method of claim 1 wherein depositing the substrate material comprises printing the material onto the casting surface.