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.
|A Square Uniform UV Laser Beam for Screen Printing Enhancement and Photoresist Ablation for Ultra-miniature Chip Resistors|
|Keywords: Printing, Direct Write, Ultraminiture|
|For today’s “Ultraminiture” metric 0603, 0402 and 0201 thick film Chip Resistors and for next generation Hybrid Circuits, screen printing technology has reached its practical production limits. Yet, the industry desperately needs this low cost manufacturing process to be cost efficient. Current lithography processes, together with their associated clean rooms, mask exposure tools, etch processes steps, and more, are not able to meet production cost goals. In this paper we examine how the Square Uniform UV beam as a post screen printing cleanup step dramatically reduces achievable feature sizes. This resolution/accuracy enhancement step is done after drying but before firing, resulting in the unfired organic materials ablating very easily and cleanly. The ease of ablation, combined with today’s high repetition rate UV-YAG lasers, make this a very high speed, cost effective process. For today’s Hybrid Circuits, having a very fast low cost method for producing very fine lines with vertical walls is extremely attractive, particularly in high frequency applications. The termination of the Ultraminiture Chip R’s is also addressed. After the plate of chip R’s is completed and fired, they are coated with a non-photosensitive resist that is easily ablated with the UV-YAG. Again using the square uniform beam, the metal pads are precisely defined by the ablation of the resist with the square uniform beam, before the rows of individual Chip R’s (row bars) are singlulated. Since the plate is in completed form, the square beam can be precisely aligned to the full pattern, thus assuring very high accuracy and resolution in the definition of the resistor pads before the parts are singlulated into bars for termination. This paper will show photos of the production of a 0402 metric Chip R substrate, SEM of each of the process steps, and the final plate of finished Chip R’s.|
|Edward Swenson, Senior Vice President of Research and Development
Electro Scientific Industries, Inc