Method for Transferring Thin Film to Substrate

• US 20100066683A1
• Filed: 09/17/2008
• Published: 03/18/2010
• Est. Priority Date: 09/17/2008
• Status: Abandoned Application

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: CHANG, Shih-Chang, Hotelling, Steve Porter, Huang, Lili
• Application Number:
  US12/212,478
• Publication Number:
  US 20100066683A1
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: B32B 17/06 comprising glass as the main or only constituent of a layer, next to another layer of a specific material
• CPC Class Codes: B32B 2457/208 Touch screens
• CPC Class Codes: B32B 37/025 Transfer laminating

Abstract

A method for transferring single layer thin film from a temporary substrate to a target substrate is disclosed. A base layer may be fabricated onto a fabrication sheet. A single layer thin film of conductive material may be patterned onto the base layer. A temporary transfer substrate may be adhered to the single layer thin film. The fabrication sheet may be removed and the base layer-patterned single layer thin film-temporary transfer substrate block transferred to a target substrate, where the base layer may contact the target substrate. Upon completion of the transfer, the temporary transfer substrate may be removed.

Claims

1. A method for transferring a thin film to a substrate, comprising:

applying a base layer to a fabrication sheet;

patterning a single layer of thin film on top of the base layer;

adhering a transfer layer on top of the patterned single layer;

removing the fabrication sheet from the base layer;

transferring the combined base layer, patterned single layer, and transfer layer to a surface of a substrate, the base layer being in contact with the substrate surface; and

removing the transfer layer from the patterned single layer.

2. The method of claim 1, wherein the patterning of the single layer of thin film comprises forming a plurality of portions of conductive material into co-planar touch sensors.

3. The method of claim 1, wherein the adhering of the transfer layer comprises:

depositing a layer of removable adhesive over the patterned single layer; and

placing the transfer layer on top of the removable adhesive layer to adhere to the patterned single layer.

4. The method of claim 1, wherein the removing of the fabrication sheet comprises chemical etching of the fabrication sheet.

5. The method of claim 1, wherein the transferring of the combined base layer, patterned single layer, and transfer layer comprises:

depositing a permanent adhesive on the surface of the substrate; and

placing the base layer on top of the permanent adhesive to adhere the combined base layer, patterned single layer, and transfer layer to the substrate surface.

6. The method of claim 3, wherein the removing of the transfer layer comprises dissolving the removable adhesive in a solvent.

7. The method of claim 1, wherein the base layer includes etch stopping material.

8. The method of claim 1, wherein the single layer of thin film includes a conductive material.

9. The method of claim 8, wherein the conductive material is indium tin oxide (ITO).

10. The method of claim 1, wherein the transfer layer includes a polymer.

11. The method of claim 1, wherein the base layer includes plastic.

12. The method of claim 11, wherein the applying of the base layer comprises bonding the plastic to the fabrication sheet.

13. The method of claim 11, wherein the removing of the fabrication sheet comprises de-bonding the plastic from the fabrication sheet.

14. The method of claim 1, wherein the substrate is a cover material for a touch sensitive device.

15. A method for transferring a thin film to a substrate, comprising:

providing a flexible transfer block on a fabrication sheet comprising

a flexible layer placed on the fabrication sheet,

a patterned single layer of thin film formed on top of the flexible layer, and

a transfer layer adhered on top of the patterned single layer;

removing the fabrication sheet from the flexible layer;

transferring the flexible transfer block to a substrate having a substantially non-flat surface, with the flexible layer adjacent to the substrate; and

removing the transfer layer from the patterned single layer.

16. The method of claim 15, the substantially non-flat surface being a curved surface, wherein the transferring of the flexible transfer block is to the curved surface of the substrate to conform thereto.

17. The method of claim 15, the substantially non-flat surface being a curved surface opposite a substantially flat surface, wherein the transferring of the flexible transfer block is to the substantially flat surface of the substrate.

18. The method of claim 15, the substrate being deformable so as to form the substantially non-flat surface, wherein the flexible transfer block deforms with the substrate so as to conform to the deformable substantially non-flat surface of the substrate.

19. The method of claim 15, the substrate being flexible so as to form the substantially non-flat surface, wherein the flexible transfer block flexes with the substrate so as to conform to the flexible substantially non-flat surface of the substrate.

20. A method for transferring a thin film to a substrate, comprising:

forming a thin film block having a base layer formed on a fabrication sheet, a single layer of thin film forming a pattern on the base layer, and a temporary layer adhered on top of the patterned single layer;

cutting the thin film block into smaller blocks, each smaller block having a portion of the fabrication sheet, a portion of the base layer formed on the portion of the transparent sheet, a portion of the single layer of thin film forming a pattern on the portion of the base layer, and a portion of the temporary layer adhered on top of the portion of the patterned single layer; and

for each smaller block,

removing the portion of the fabrication sheet from the portion of the base layer,

applying the combined portions of the base layer, patterned single layer, and temporary layer to a surface of a cover glass, the portion of the base layer being adhered to the surface of the cover glass, and

removing the portion of the temporary layer from the portion of the patterned single layer.

21. The method of claim 20, further comprising:

for each smaller block, attaching a flex circuit to the portion of the patterned single layer after the removing of the portion of the temporary layer.

22. The method of claim 20, further comprising:

for each smaller block, applying an anti-reflective layer to the portion of the patterned single layer after the removing of the portion of the temporary layer.

23. The method of claim 20, wherein the cover glass has a front surface configured to receive a touch and a back surface opposite the front surface, the back surface being adhered to the portion of the base layer.

24. The method of claim 20, wherein the cover glass and the combined portions of the base layer and patterned single layer form a touch sensitive device.

25. In a system including a sensor panel having a touch surface with a front side configured to receive a touch and a back side opposite the front side, a method for transferring a thin film to the sensor panel, the method comprising:

applying a base layer to a substrate;

patterning at least one single layer of thin film onto the base layer, the at least one single layer of thin film comprising conductive material configured to detect the touch;

adhering a transfer layer on top of the at least one patterned single layer;

removing the substrate from the base layer;

transferring the combined base layer, at least one patterned single layer, and transfer layer to the back side of the touch surface with the base layer being disposed on the back side and the transfer layer being disposed furthest from the back side; and

removing the transfer layer from the at least one patterned single layer.

26. The method of claim 25, wherein the patterning of the at least one single layer of thin film comprises:

patterning a first single layer of thin film onto the base layer;

placing a dielectric material on top of the first patterned single layer of thin film; and

patterning a second single layer of thin film on top of the dielectric material,

wherein the transfer layer is adhered on top of the second patterned single layer.

27. The method of claim 25, wherein the patterning of the at least one single layer of thin film comprises:

patterning a first single layer of thin film onto the base layer;

patterning a second single layer of thin film on top of the first single layer,

wherein the transfer layer is adhered on top of the second patterned single layer.

28. A multi-touch panel comprising:

a touch surface having a front side configured to receive a touch and a back side opposite the front side; and

a plurality of co-planar single layer touch sensors configured to detect the touch, the touch sensors having been fabricated in a single layer on one side of a transfer substrate and transferred to the back side of the touch surface from the one side of the transfer substrate.

29. The multi-touch panel of claim 28 incorporated into a computing system.

30. The multi-touch panel of claim 28 incorporated into a mobile telephone.

31. The multi-touch panel of claim 28 incorporated into a digital media player.

32. A mobile telephone including a touch sensor panel, the touch sensor panel comprising:

a touch surface having a front side configured to receive a touch and a back side opposite the front side; and

a plurality of co-planar single layer touch sensors configured to detect the touch, the touch sensors having been fabricated in a single layer on one side of a transfer substrate and transferred to the back side of the touch surface from the one side of the transfer substrate.

33. A digital media player including a touch sensor panel, the touch sensor panel comprising:

a touch surface having a front side configured to receive a touch and a back side opposite the front side; and

a plurality of co-planar single layer touch sensors configured to detect the touch, the touch sensors having been fabricated in a single layer on one side of a transfer substrate and transferred to the back side of the touch surface from the one side of the transfer substrate.

34. A computer including a touch sensor panel, the touch sensor panel comprising:

a touch surface having a front side configured to receive a touch and a back side opposite the front side; and

a plurality of co-planar single layer touch sensors configured to detect the touch, the touch sensors having been fabricated in a single layer on one side of a transfer substrate and transferred to the back side of the touch surface from the one side of the transfer substrate.