Laser transfer deposition

• US 4,987,006 A
• Filed: 03/26/1990
• Issued: 01/22/1991
• Est. Priority Date: 03/26/1990
• Status: Expired due to Term

• Current Assignee: AMP Limited
• Original Assignee: AMP Limited
• Inventors: Williams, Richard T., Wu, Jeff C., Wrisley, David B. Jr.
• Primary Examiner(s): Morgenstern, Norman
• Assistant Examiner(s): Padgett, Marianne
• Application Number:
  US07/498,875
• Time in Patent Office: 302 Days
• Field of Search: 427/53.1, 427/42, 427/43.1, 427/248.1, 427/250, 427/123, 427/124, 427/125, 427/126.1, 427/96, 505/732
• US Class Current: 427/597
• CPC Class Codes: B41M 5/24 Ablative recording, e.g. by burning marks; Spark recording marking by high energetic means, e.g. by laser otherwise than burning or ablative removal B41M5/26; materials or methods for recording or reproduction by optical means G11B7/00
• CPC Class Codes: B44C 1/14 Metallic leaves or foils, e.g. gold leaf
• CPC Class Codes: C23C 26/00 Coating not provided for in groups C23C2/00 - C23C24/00
• CPC Class Codes: H05K 3/046 by selective transfer or selective detachment of a conductive layer

Abstract

This invention is directed to a method for producing a smooth and continuous pressure bonded layer of a material such as gold or other precious metal, to a substrate, such as a metal substrate, through the driving force of a pulsed laser. The method comprises the steps of selecting a laser transparent substrate, applying thereto a thin polymeric film, where said polymer is characterized by a high optical coefficient of absorption to the wavelength of said laser. Preferably, such coefficient is at least 2×10⁴ cm^-1. To the polymeric film, a thin layer or film of the material, such as gold is applied. Thereafter, the laser transparent substrate, containing the dual layers is placed in close proximity to the substrate or workpiece upon which such material is to be deposited. To this assembly, a pulsed laser is directed through the transparent substrate toward the polymeric film and material layer, whereby the laser energy is absorbed by the polymeric causing heating and vaporization thereof over a controlled depth of such polymer film. The vaporization provides the necessary pressure to blow-off the remaining polymer film and propel the material layer onto the substrate or workpiece. The resulting pressure bonded layer, i.e. gold or other precious metal, is smooth and continuous.

Claims

1. In a method for producing a smooth and continuous pressure bonded layer of a material, selected from the group consisting of conductive, semiconductive, superconductive and insulating materials, on a base material through the driving force of a pulsed laser, the improvement comprising in combination therewith the steps of

(a) selecting a laser transparent substrate,

(b) applying thereto a thin polymeric film, where said polymer is characterized by a high optical coefficient of absorption to the wavelength of said laser,

(c) applying to said polymeric film a thin layer of said material for pressure bonding to said base material,

(d) placing said base material in close proximity to said thin layer of material, and

(e) directing pulsed laser energy through said transparent substrate toward said polymeric film and said layer of material to be pressure bonded, whereby said laser energy is absorbed by said polymer causing heating and vaporization thereof to a controlled depth of said polymeric film, leaving remaining portions of said polymeric film unvaporized after said depth, to act as support for said thin layer of material to be pressure bonded, said vaporization providing the necessary pressure to blow-off said remaining portions of polymeric film, whereby to propel said material for pressure bonding on to said base material.

2. The method according to claim 1 wherein said material to be pressure bonded is gold, a gold alloy, palladium, or palladium alloy.

3. The method according to claim 1 wherein the method is practiced in a controlled environment to minimize oxidation of said material to be bonded and base material.

4. The method according to claim 1 wherein the material to be bonded is non-oxidizing and is conducted in an air environment.

5. The method according to claim 1 wherein said laser transparent substrate is a member selected from the group consisting of glass, quartz and sapphire.

6. The method according to claim 1 wherein said laser transparent substrate is a polymer having an optical coefficient of absorption of less than about 10¹ cm^-1.

7. The method according to claim 2 wherein the base material is a metal.

8. The method according to claim 1 wherein said laser is an excimer laser and said polymeric film has an optical coefficient of absorption of at least 2×

10⁴ cm^-1.