Develop temperature and process study on a thick film photoresist

Abstract

In a variety of microlithographic applications the importance of thick film photoresist continues to grow. Thick film photoresists are evolving into materials, which can meet the demand for smaller features while maintaining good exposure latitude, depth of focus, sidewall profiles, and photospeed. It is know that the performance characteristics of photoresists will change with changing process conditions and that the best performance of a photoresist is achieved by optimization of these conditions. One of the more critical steps in the lithographic process is development, which requires a tight process control. In our study we evaluated the effects of developer temperature and developing mode such as spray, spray/puddle, and immersion. The performance of an advanced thick film photoresists was examined regarding to resolution, depth of focus, exposure latitude, profile, photospeed, and scumming. A full lithographic evaluation was carried out. Assessment of the thick film photoresist, which is a commercially available product, was done on a Nikon. This paper includes a discussion, looking at the best compromise of performance based on temperature and develop process.