Method for making conductive circuits using powdered metals

• US 20050039329A1
• Filed: 09/29/2004
• Published: 02/24/2005
• Est. Priority Date: 09/10/2001
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Kuhns, David W., Koskenmaki, David C.
• Granted Patent: US 7,237,330 B2
• Time in Patent Office: Days
• US Class Current: 29/825
• CPC Class Codes: H05K 3/102 by bonding of conductive powder, i.e. metallic powder H05K3/12 takes precedence
• CPC Class Codes: Y10T 29/49117 Conductor or circuit manufacturing
• CPC Class Codes: Y10T 29/49126 Assembling bases
• CPC Class Codes: Y10T 29/49128 Assembling formed circuit to base
• CPC Class Codes: Y10T 29/49155 Manufacturing circuit on or in base
• CPC Class Codes: Y10T 428/24273 including aperture
• CPC Class Codes: Y10T 428/24331 including nonapertured component
• CPC Class Codes: Y10T 428/24479 including variation in thickness
• CPC Class Codes: Y10T 428/24917 including metal layer

Abstract

A method for making an electrically conductive pattern, including: (a) depositing on a substrate a metal powder composition consisting essentially of at least one metal powder, wherein the substrate is selected from the group consisting of paper and materials that are at least about 10% compressible; and (b) densifying the composition to form a conductive pattern on the substrate.

Claims

1. A method for making an electrically conductive pattern, comprising:

(a) depositing on a substrate a metal powder composition consisting essentially of at least one metal powder, wherein the substrate is selected from the group consisting of paper and materials that are at least about 10% compressible; and

(b) densifying the composition to form a conductive pattern on the substrate.

2. The method of claim 1, comprising applying, prior to step (b), a first pressure in a pattern to the composition to capture the composition on the substrate.

3. The method of claim 2, further comprising removing uncaptured metal power composition from the substrate.

4. The method of claim 1, wherein an densifying step (b) comprises applying a second pressure, different from the first pressure, to the composition to form the conductive pattern.

5. The method of claim 2, wherein the application of a pressure in a pattern and the densification are performed in a single step.

6. The method of claim 2, wherein the densifying step (b) comprises applying at least one of pressure, heat, microwave energy and acoustic energy.

7. The method of claim 4, wherein the densifying step (b) further comprises applying at least one of heat, microwave energy and acoustic energy.

8. The method of claim 5, wherein the densifying step (b) comprises applying at least one of pressure, heat, microwave energy and acoustic energy.

9. The method of claim 2, wherein application of the first pressure in a pattern further comprises the application of at least one of heat, microwave energy and acoustic energy.

10. The method of claim 1, further comprising removing oxides from the metal powders in the composition.

11. The method of claim 1, wherein the substrate is selected from the group consisting of paper and materials that are at least about 20% compressible.

12. The method of claim 1, wherein the materials that are at least about 10% compressible are selected from the group consisting of microporous materials, nonwoven materials and woven materials.

13. The method of claim 1 wherein the metal powder composition consists essentially of at least one metal powder selected from the group consisting of copper, tin, lead, silver, gold, platinum, graphite, aluminum, nickel, iron, steel and zinc and alloys and combinations thereof.

14. The method of claim 13, wherein the metal powder comprises copper.

15. The method of claim 14, wherein the copper comprises dendritic copper.

16. The method of claim 14, wherein the metal powder further comprises tin.

17. The method of claim 1 wherein the metal powder composition further comprises a liquid.

18. The method of claim 17, wherein the liquid comprises water.

19. The method of claim 4, wherein the second pressure is applied substantially equally to the metallized and unmetallized portions of the substrate.

20. The method of claim 1, wherein the method is conducted at a temperature less than the annealing temperature of a metal powder in the metal powder composition.

21. The method of claim 1, wherein the method is conducted at a temperature less than about 50°

C.

22. The method of claim 7, wherein the temperature in the densifying step (b) is about 50 to about 300°

C.

23. The method of claim 1, wherein the method is conducted at a pressures of about 20 MPa to about 2000 MPa.

24. The method of claim 1, wherein the metal powder composition fills at least one via in the substrate and wherein the metal powder bridges the via and provides a conductive path across the via after step (a).