Method of producing and depositing a metal film

• US 6,548,122 B1
• Filed: 11/19/1999
• Issued: 04/15/2003
• Est. Priority Date: 09/16/1997
• Status: Expired due to Fees

• Current Assignee: National Institute for Strategic Technology Acquisition and Commercialization, SRI International, Inc.
• Original Assignee: SRI International, Inc.
• Inventors: Sharma, Sunity, Narang, Subhash, Bhasin, Kuldip, Sharma, Madan Lal
• Primary Examiner(s): Beck, Shrive P.
• Assistant Examiner(s): Michener, Jennifer Kolb
• Application Number:
  US09/444,031
• Time in Patent Office: 1,243 Days
• Field of Search: 427/559, 427/556, 427/96, 427/552, 427/256, 427/558, 427/597, 427/555, 427/226, 427/229, 430/313, 430/315, 428/209, 428/901
• US Class Current: 427/559
• CPC Class Codes: G03F 7/16 Coating processes; Apparatus therefor applying coatings to base materials in general B05; applying photosensitive compositions to base for photographic purposes G03C1/74
• CPC Class Codes: H05K 3/105 by conversion of non-conductive material on or in the support into conductive material, e.g. by using an energy beam
• CPC Class Codes: H05K 3/1241 by ink-jet printing or drawing by dispensing
• CPC Class Codes: Y10S 428/901 Printed circuit
• CPC Class Codes: Y10T 428/24909 Free metal or mineral containing

Abstract

Methods and apparatus are provided in which a metal precursor is formed in a process that includes the following steps: depositing a metal precursor on a substrate; adding an energy to reduce the metal precursor and to precipitate metal on the substrate as a continuous metal layer; and selecting the metal precursor and the energy such that the purity of the continuous metal layer is greater than 85%, and/or the deposited layer has an electrical conductivity substantially that of a pure metal. Methods and apparatus are also provided in which a metal is deposited onto a substrate by a process which includes the following steps: depositing the metal precursor onto the substrate in a desired pattern; and applying sufficient energy to decompose the precursor to precipitate metal in a continuous metal layer in the desired pattern.

Claims

1. A method of laying down a metal on a substrate installed in or forming part of an electronic device comprising:

depositing a metal precursor comprising a metallic salt directly on a substrate installed in or forming part of an electronic device;

adding an energy derived from an extended source;

reducing the metal precursor and precipitating metal on the substrate installed in or forming part of an electronic device as a continuous metal layer, wherein the step of reducing the metal precursor occurs at a temperature less than about 150°

C. and the continuous layer is an electrical conductor; and

selecting the metal precursor and the energy such that the continuous layer is an electrical conductor and comprises at least 85% of the metal wherein the metal comprises an element where a highest d orbital occupied by an electron of the element is the 3d, 5d, or 6d.

2. The method of claim 1, wherein the continuous layer has an electrical conductivity of pure copper.

3. The method of claim 1, wherein the metal precursor comprises a ligand.

4. The method of claim 3, wherein the ligand comprises a material selected from the group consisting of an amine, an amide, a phosphine, a sulfide, and an ester.

5. The method of claim 3, wherein the ligand is selected from the group consisting of a nitrogen donor, a sulfur donor, and a phosphorus donor.

6. The method of claim 1, wherein the extended source is an infra-red source.

7. The method of claim 1, wherein the extended source is a microwave source.

8. The method of claim 1, wherein the coating has a thickness of less than about 100 nanometers.

9. The method of claim 1, wherein the metal comprises cobalt, copper, nickel, zinc, vanadium, chromium, platinum, gold, or tungsten.

10. The method of claim 9, wherein the metal comprises copper.

11. A method of depositing a metal in a desired pattern onto a substrate installed in or forming part of an electronic device by:

depositing a metal precursor directly onto the substrate installed in or forming part of an electronic device in the desired pattern, wherein the metal precursor comprises a metallic salt;

applying sufficient energy to the metal precursor in the form of an extended source;

reducing the metal precursor, wherein the step of reducing the metal precursor occurs at a temperature less than about 150°

C.; and

precipitating a metal in the desired pattern, said layer having an electrical conductivity substantially that of the pure metal wherein the metal comprises an element where a highest d orbital occupied by an electron of the element is the 3d, 5d, or 6d.

12. The method of claim 11, wherein the pattern comprises an electrical circuit.

13. The method of claim 11, wherein the step of depositing the precursor is selected from the group consisting of spraying, stamping, roller printing, letter press printing, gravure printing, screen printing, flexographic printing, planographic printing, offset printing, and mimeograph printing.

14. The method of claim 11, wherein the step of reducing the metal precursor occurs at a temperature less than about 100°

C.

15. The method of claim 11, wherein the steps of reducing the metal precursor occurs at about room temperature.

16. The method of claim 11, wherein the metal comprises cobalt, copper, nickel, zinc, vanadium, chromium, platinum, gold, or tungsten.