Statistically designed polyimide coating process for TAB bumping

Design of experiments and statistical data analysis were used to develop a wafer coating process for straight wall bumping of 6" wafers for TAB (tape automated bonding). The effect of important parameters and their interactions on polyimide coat thickness, uniformity, and quality were identified, and models were developed. Using the results of the experiments, a dynamic coating process was developed which provided well-controlled polyimide coating for the straight wall bumping process. Subsequent results showed excellent correlation between measured values and predicted values from models