Spray Photoresist Thickness Uniformity Improvement
Original Publication Date: 1985-Aug-01
Included in the Prior Art Database: 2005-Feb-19
In the application of liquid photoresist for use in the photolithographic defining of circuitry for substrates, the uneven application of resist results in thickness variations. When resist thickness varies, areas where the resist is too thick cannot receive enough expose energy to achieve adequate adhesion and the resist film will lift from the substrate when the resist is developed. This results in shorts or opens of the circuitry when defined through etching. A setup and process that significantly reduces the resist thickness variation is described in the following. In current practice the method used to coat photoresist on substrates is spraying. The substrates 1 (Fig. 1) are loaded on a conveyor 2, and the spray head 3 reciprocates transversely in the y direction depositing the resist 4 in a row-like configuration.