3-D laser patterning process utilizing horizontal and vertical patterning

• US 6,114,097 A
• Filed: 02/13/1995
• Issued: 09/05/2000
• Est. Priority Date: 02/13/1995
• Status: Expired due to Fees

• Current Assignee: Lawrence Livermore National Security LLC (Government of the United States of America)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Malba, Vincent, Bernhardt, Anthony F.
• Primary Examiner(s): Young, Christopher G.
• Application Number:
  US08/387,495
• Time in Patent Office: 2,031 Days
• Field of Search: 430/313, 430/314, 430/315, 430/318, 430/311, 430/329
• US Class Current: 430/314
• CPC Class Codes: G03F 7/164 using electric, electrostatic or magnetic means; powder coating
• CPC Class Codes: G03F 7/2053 using a laser ablative removal B41C
• CPC Class Codes: H05K 3/32 electrically connecting electric components or wires to printed circuits

Abstract

A process which vastly improves the 3-D patterning capability of laser pantography (computer controlled laser direct-write patterning). The process uses commercially available electrodeposited photoresist (EDPR) to pattern 3-D surfaces. The EDPR covers the surface of a metal layer conformally, coating the vertical as well as horizontal surfaces. A laser pantograph then patterns the EDPR, which is subsequently developed in a standard, commercially available developer, leaving patterned trench areas in the EDPR. The metal layer thereunder is now exposed in the trench areas and masked in others, and thereafter can be etched to form the desired pattern (subtractive process), or can be plated with metal (additive process), followed by a resist stripping, and removal of the remaining field metal (additive process). This improved laser pantograph process is simpler, faster, move manufacturable, and requires no micro-machining.

Claims

1. A three-dimensional patterning process, comprising:

depositing at least one metal layer on a surface to be patterned,

isotropically depositing a layer of photoresist on vertical and horizontal surfaces of the thus deposited metal layer,

patterning the photoresist on vertical and horizontal surface areas using a directed light source,

developing the thus patterned areas of the photoresist to expose metal in the patterned areas,

processing exposed metal in the patterned areas by a technique selected from a group consisting of etching the metal and plating the metal,

stripping the remaining photoresist, and

removing any of the unprocessed remainder of the metal layer.

2. The process of claim 1, wherein the step of patterning is carried out with a laser pantograph as the directed light source and at an angle other than 90°

for vertical surfaces.

3. The process of claim 1, wherein the at least one metal layer is deposited by a sputtering technique.

4. The process of claim 1, wherein the photoresist was deposited by electroplating.

5. The process of claim 1, wherein the developing of the patterned areas of the photoresist was carried out using aqueous sodium carbonate or aqueous lactic.

6. The process of claim 1, wherein the exposed metal is etched by an etchant selected from the group consisting of ammonium persulfate, sodium persulfate ferric chloride, and cupric chloride.

7. The process of claim 1, wherein the exposed metal is plated by an acidic copper sulfate solution.

8. The process of claim 1, additionally including depositing an adhesion layer on the surface to be patterned prior to depositing the metal layer.

9. The process of claim 1, wherein the surface to be patterned is a substrate selected from the group consisting of silicon, glass, plastic, ceramic and laminated material.

10. The process of claim 1, wherein the surface to be patterned is of an artistic material.

11. The process of claim 1, wherein the photoresist is an electrodeposited photoresist, capable of covering the surface of the metal conformally, thereby coating the vertical as well as the horizontal surfaces thereof.

12. The process of claim 8, wherein the adhesion layer is composed of material, selected from the group consisting of Ti, TiW, Cr, Ta, TiN and W.

13. The process of claim 1, wherein the at least one metal layer is composed of metal selected from the group of copper, gold, nickel, and platinum.

14. A process for interconnecting IC chips to a substrate via sidewall patterning, comprising:

attaching the chip to the substrate utilizing an adhesive, and

forming a fillet at the region of connection following attaching the chip to the substrate.

15. The process of claim 14, wherein the chip is attached to the substrate by a film of an adhesive selected from the group consisting of eutectic solder, epoxy, thermoset adhesive, thermoplastic adhesive.

16. The process of claim 14, wherein the fillet is formed from an adhesive material.

17. A process for 3-D laser patterning, comprising:

sputtering an adhesion layer on a surface of a substrate,

depositing a film seed layer on the adhesive surface, and

carrying out a subtractive process or an additive process on horizontal and vertical surfaces of the film seed layer following depositing the film seed layer.

18. The process of claim 17, wherein the subtractive process is carried out by:

electroplating a layer of conductive metal on the film seed layer,

applying an electrodeposited photoresist on the horizontal and vertical surfaces of the layer of conductive metal,

drying and soft-baking the applied photoresist, exposing horizontal and vertical areas of the photoresist to laser patterning, developing the photoresist, etching the conductive metal exposed by the photoresist development,

removing the remaining photoresist, and

removing the remaining adhesive layer.

19. The process of claim 17, wherein the additive process is carried out by:

applying a layer of electrodeposited photoresist directly onto horizontal and vertical surfaces of the film seed layer,

soft-baking the photoresist,

exposing horizontal and vertical surface areas of the photoresist to laser patterning,

developing the patterned areas of the photoresist,

depositing a conductive metal on exposed areas of the seed layer located in the patterned photoresist areas,

removing the remaining photoresist, and

removing the remaining seed layer and adhesive layer.

20. A three dimensional patterning process, comprising:

isotropic deposition of a photodefinable layer on both vertical and horizontal areas of a surface,

patterning at least one area on the layer by exposure of the photodefinable layer to a directed light source,

developing the thus patterned areas to form exposed material

processing the exposed material under the patterned areas, and

stripping the remaining photodefinable layer.

21. The process of claim 20, wherein the step of exposure is carried out by a laser.

22. The process of claim 20, wherein the photodefinable layer is electroplated photoresist.

23. The process of claim 20, wherein the exposed material is metal and its processing consists of etching.

24. The process of claim 20, wherein the exposure step and developing step are carried out simultaneously by laser ablation.

25. The process of claim 20, wherein the processing consists of electroless deposition of metal.

26. A three dimensional patterning process comprising;

depositing at least one seed layer on vertical and horizontal areas of a surface to be patterned,

isotropic deposition of a photodefinable layer on the seed layer,

exposing material under patterned horizontal and vertical areas of the layer,

developing the patterned areas,

processing the exposed material,

stripping the remaining photodefinable layer, and

removing any remainder of the seed layer.

27. The method of claim 26, wherein the seed layer consists of at least one metal layer.

28. The method of claim 26, wherein the processing consists of electroplating.