Copperless flexible circuit

• US 20060131616A1
• Filed: 12/21/2004
• Published: 06/22/2006
• Est. Priority Date: 12/21/2004
• Status: Abandoned Application

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Lueneburg, David C., Devaney, Douglas E.
• Application Number:
  US11/018,948
• Publication Number:
  US 20060131616A1
• Time in Patent Office: Days
• US Class Current: 257/226
• CPC Class Codes: A61B 2562/02 Details of sensors specially adapted for in-vivo measurements
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/1486 using enzyme electrodes, e.g. with immobilised oxidase
• CPC Class Codes: H05K 1/09 Use of materials for the conductive, e.g. metallic pattern
• CPC Class Codes: H05K 2201/0141 Liquid crystal polymer [LCP]
• CPC Class Codes: H05K 2201/0352 Differences between the conductors of different layers of a multilayer
• CPC Class Codes: H05K 3/108 by semi-additive methods; masks therefor characterised by metallic etch mask H05K3/062; electroplating methods or apparatus H05K3/241
• CPC Class Codes: H05K 3/388 by the use of a metallic or inorganic thin film adhesion layer

Abstract

This invention relates to a copperless flexible circuit; more particularly, a two-sided copperless flexible circuit.

Claims

1. An article comprising:

a two-sided circuit comprising a flexible polymeric substrate having two opposing surfaces and

copperless metal traces or features on each substrate surface.

2. The article of claim 1 wherein the polymeric substrate is a semi-crystalline polymer having a quasi-amorphous surface.

3. The article of claim 1 wherein the metal circuit comprises a noble metal.

4. The article of claim 3 wherein the noble metal is gold.

5. The article of claim 1 wherein the metal on both substrate surfaces is the same.

6. The article of claim 1 wherein the metal on each substrate surface is different.

7. The article of claim 1 wherein the two-sided circuit forms a portion of a biosensor.

8. The article of claim 7 wherein the biosensor is a glucose sensor.

9. The article of claim 1 wherein the two-sided circuit forms a portion of a hard disk drive.

10. The article of claim 1 wherein the substrate thickness is greater than the minimum distance between two traces on opposite surfaces of the substrate.

11. The article of claim 1 wherein the substrate thickness is less than the minimum distance between two traces on a first surface of the substrate and wherein a ground plane is on a second opposing substrate surface.

12. A method comprising:

providing a flexible polymeric substrate having two opposing surfaces, and forming copperless metal traces or features on each substrate surface.

13. The method of claim 12 wherein the polymeric substrate is treated with rapid, pulsed high intensity ultra-violet light before the copperless metal traces or features are formed.

14. The method of claim 12 wherein the formation of the metal traces or features comprises:

applying a copperless metal to opposing sides of a flexible polymeric substrate, forming a photoresist mask in the desired circuit pattern;

removing the exposed portions of the metal layers;

removing the photoresist mask to expose the desired circuit pattern; and

plating the patterned metal layers.

15. The method of claim 12 further comprising:

applying a covercoat layer over at least a portion of the metal layer; and

patterning the covercoat layer to expose at least a portion of the metal layer.

16. The method of claim 15 further comprising plating the exposed metal layer.

17. The method of claim 12 comprising:

applying a copperless metal to opposing sides of a flexible polymeric substrate, forming a photoresist mask in the negative image of the desired circuit pattern;

plating the exposed portions of the metal layers;

removing the photoresist mask; and

etching the copperless metal until the exposed portion is removed from the substrate.

18. The method of claim 17 further comprising:

applying a covercoat layer over at least a portion of the metal layer; and

patterning the covercoat layer to expose at least a portion of the metal layer.

19. The method of claim 18 further comprising plating the exposed metal layer.

20. The method of claim 12 comprising:

applying a copperless metal to opposing sides of a flexible polymeric substrate, forming a photoresist mask in the image of the desired circuit pattern;

etching the exposed copperless metal until it is removed from the substrate; and

removing the photoresist mask.

21. The method of claim 20 further comprising:

applying a covercoat layer over at least a portion of the metal layer; and

patterning the covercoat layer to expose at least a portion of the metal layer.

22. The method of claim 21 further comprising plating the exposed metal layer.