Here is the abstract you requested from the CICMT_2007 technical program page. This is the original abstract submitted by the author. Any changes to the technical content of the final manuscript published by IMAPS or the presentation that is given during the event is done by the author, not IMAPS.
|UV Laser Processing of Alumina (AI(2)0(3)) Ultra-miniature Circuit Substrates|
|Keywords: Alumina, Scribing, UV-YAG|
|For over thirty years, the laser has been used extensively to singulate multi-up circuits on Alumina substrates. As circuit densities increased, the CO-2 laser was replaced by the IR YAG laser. In this paper, we report on a new UV laser scribing method which is specifically directed to the singulation of today’s “ultraminiature” metric” 0603, 0402 and 0201 surface mounted passive components. Although it can be applied to many different passive components types, we will report on the singulation of surface mounted Ultraminiature Chip Resistors. The solid state UV-YAG laser has made tremendous strides in available power, repetition rate and reliability. These include making ever increasing high density vias in HDI circuit boards and organic packages. Using this production proven UV technology, a new unique scribing method has been developed. With the Solid State UV lasers, a much shorter wavelength and smaller beam spot size are produced. Also, with its much better absorption in the ceramic, the UV removes the material with very limited melting and thus produces virtually no resolidification of the ceramic material. This forms a sharp, shallow “V” grove that permits very sharp clean breaks. Optical and SEM pictures will be presented showing the very straight side walls after breaking that are produced from a single high speed pass with the UV laser pulses. Another major advantage of the UV laser is its ability to ablate organic materials and cleanly cut metals with very minimal slag and heat effected zone. The superior lasers material interaction allows a process change, where the scribing can be done at the end of the production process after the entire substrate has been screened, unlike today’s process with the IR laser where the scribing is done on the bare ceramic substrate.|
|Edward Swenson, Senior Vice President of Research and Development
Electro Scientific Industries, Inc.