Printed circuit board

• US 4,960,614 A
• Filed: 06/14/1989
• Issued: 10/02/1990
• Est. Priority Date: 02/06/1987
• Status: Expired due to Fees

• Current Assignee: Poly-Flex Circuits Incorporated (PARLEX USA LLC)
• Original Assignee: Key-Tech, Inc.
• Inventors: Durand, David
• Primary Examiner(s): Niebling, John F.
• Assistant Examiner(s): Gorgos, Kathryn
• Application Number:
  US07/365,712
• Time in Patent Office: 475 Days
• Field of Search: 427/54.1, 427/96, 522/96, 522/103, 522/1, 522/107, 522/166
• US Class Current: 427/511
• CPC Class Codes: C09D 11/101 Inks specially adapted for printing processes involving curing by wave energy or particle radiation, e.g. with UV-curing following the printing
• CPC Class Codes: C09D 11/52 Electrically conductive inks
• CPC Class Codes: H01B 1/22 the conductive material comprising metals or alloys
• CPC Class Codes: H01F 41/16 the magnetic material being applied in the form of particles, e.g. by serigraphy , to form thick magnetic films or precursors therefor H01F41/18 -H01F41/24 take precedence
• CPC Class Codes: H05K 1/095 for polymer thick films, i.e. having a permanent organic polymeric binder
• CPC Class Codes: H05K 2201/083 Magnetic materials
• CPC Class Codes: H05K 2203/104 Using magnetic force, e.g. to align particles or for a temporary connection during processing
• CPC Class Codes: H05K 3/1283 After-treatment of the printed patterns, e.g. sintering or curing methods
• CPC Class Codes: H05K 3/245 Reinforcing conductive patterns made by printing techniques or by other techniques for applying conductive pastes, inks or powders; Reinforcing other conductive patterns by such techniques

Abstract

A method for producing a circuit board involves printing a U.V. curable ink onto a substrate in a desired circuit pattern and curing the ink by exposing it to a pulsed U.V. source having an output in the region between 360 nm and 420 nm in a pulsing manner consisting of 5 to 8 one-half second exposure periods where each exposure period is followed by a non-exposure period of about 2 to 3 seconds.

Claims

1. A method for producing a circuit board having conductive circuit elements with a specific resistivity of less than 0.05 ohm-cm² patterned on a nonconductive substrate comprising:

a. printing a U.V. curable ink onto the nonconductive substrate in a desired circuit pattern, and

b. effecting U.V. radiation cure of the U.V. curable ink by exposing said U.V. curable ink to a U.V. source having an output in a region between 360 nm and 420 nm in a pulsing manner consisting of 5 to 8 one-half second exposure periods, each exposure period followed by a non-exposure period of about 2 to 3 seconds.

2. The method of claim 1 wherein said U.V. source is an electrodeless U.V. source.

3. The method of claim 2 wherein said electrodeless U.V. source is provided with iron oxide as a dopant.

4. The method of claim 1 wherein said U.V. curable ink comprises from about 30 to 33 weight percent of a thermosetting resin binder and 70 to 67 weight percent of spherical or spheroidal conductive particles having a particle size distribution ranging from 1 to 30 microns.

5. The method of claim 4 wherein said conductive particles comprise silver coated glass spheres wherein the silver comprises about 8 to 12 weight percent based on the total weight of said silver coated glass spheres.

6. The method of claim 4 wherein said U.V. curable ink also includes an effective amount of a ketone-amine curing agent.

7. The method of claim 6 wherein said ketone-amine curing agent comprises Michler'"'"'s ketone.

8. The method of claim 7 wherein said ketone-amine curing agent comprises a mixture of benzophenone and Michler'"'"'s ketone.

9. The method of claim 4 wherein said silver coated glass spheres have an average particle size of about 15 microns.