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Method Of Obtaining Fine Patterns For Thick Photo Sensitive Materials

IP.com Disclosure Number: IPCOM000004600D
Publication Date: 2001-Feb-28
Document File: 1 page(s) / 26K

Publishing Venue

The IP.com Prior Art Database

Abstract

A method is disclosed that enables the creation of fine patterns in thick photo sensitive materials used in (but not limited to) semiconductor fabrication and assembly while optimizing desirable patterning quality over prior methods.

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Method Of Obtaining Fine Patterns For Thick Photo Sensitive Materials

A method is disclosed that enables the creation of fine patterns in thick photo sensitive materials used in (but not limited to) semiconductor fabrication and assembly while optimizing desirable patterning quality over prior methods.

The method disclosed is comprised of using multiple level focus in conjunction with simultaneous increase of intensity of exposure from surface to the bottom of the photo sensitive material. In prior art the focus is shifted from the top, through the middle, and then to the bottom of the photo sensitive material, during which attenuation of the light intensity occurs. This attenuation of light intensity resulted in poor resist wall profiles/pattern quality . This is primarily due to the breaching effect, where the penetration rate of photosensitive materials increases after photosensitive material is exposed by light. The new method disclosed provides simultaneous compensation of the light intensity attenuation with the shift in focus to best optimize the resolution of the pattern created in the photo sensitive material. This new method enables vertical wall profiles highly desirable in thick photosensitive material applications.

One example where the method would be of use is in the area chip size packaging. Chip size packaging uses thick resist patterning to form chimney's which can be filled with metal by plating (see illustration below). Once the chimneys are filled with metal the photo resist can be removed and the area once occupied by photo resist filled with resin.