Browse Prior Art Database

Infrared Laser Pattern Generation of Solder Masks

IP.com Disclosure Number: IPCOM000062563D
Original Publication Date: 1986-Dec-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Baldauf, L: AUTHOR [+4]

Abstract

A very fast, accurate, and economical method of coating printed circuit boards is described combining three technologies; Photosensitive Solder Masks, Laser Exposure, and Infrared Lasers. A very fast, accurate, and economical method of applying solder mask to printed circuit boards is accomplished by rastering an Infrared Laser across a panel that has been coated with a Photoimageable Solder Mask (PISM). Photoimageable Solder Masks are a great improvement over screen- printed solder masks. They can place an image within 0.05 mm of the desired location and that image can be accurate to +,- 0.02 mm. The disadvantage of these systems is that the raw materials cost approximately five times that of screen-printing inks.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 60% of the total text.

Page 1 of 1

Infrared Laser Pattern Generation of Solder Masks

A very fast, accurate, and economical method of coating printed circuit boards is described combining three technologies; Photosensitive Solder Masks, Laser Exposure, and Infrared Lasers. A very fast, accurate, and economical method of applying solder mask to printed circuit boards is accomplished by rastering an Infrared Laser across a panel that has been coated with a Photoimageable Solder Mask (PISM). Photoimageable Solder Masks are a great improvement over screen- printed solder masks. They can place an image within 0.05 mm of the desired location and that image can be accurate to +,- 0.02 mm. The disadvantage of these systems is that the raw materials cost approximately five times that of screen-printing inks. Unless the productivity of photoimageable solder masks is improved, their use cannot be justified on low end circuit boards. The steps in using a PISM are: Pre-Clean

Apply Solder Mask

Expose

Develop

Cure The main gate to a high speed PISM process is the imaging process itself. Usually the exposure time by itself takes almost as long as screen printing. This is due to the cycle time needed to align the glass and draw vacuum on a conventional expose machine and the low sensitivity of the PISM to ultraviolet light. One way of eliminating the handling time for photoresists is to raster a laser across the panel, exposing only the desired areas. There is no need to pull a vacuum and no glass to align. This pi...