Optimal Yield Rate in ACF Cutting Process of TFT-LCD Module Using Orthogonal Particle Swarm Optimization Based on Response Surface Design

Abstract

Anisotropic Conductive Film (ACF) is essential material in LCM (Liquid Crystal Module) process. It is used in bondingprocess to make the driving circuit conductive. Because the price of TFT-LCD is getting lower than before in recentyears, the ACF has relatively higher cost ratio. The conventional long bar ACF cutting unit is changed into short barACF cutting unit in new bonding technology. However, the new type machine was not optimized in process controland mechanical design. Therefore, the failure rate of new ACF cutting process is much higher than the one of theconventional process. This wastes the ACF material and rework cost is considerably large. How to make themanufacturing cost down effectively and promote the product quality is the main issue to maintain competitioncapability for the product. Therefore, the orthogonal particle swarm optimization (OPSO) is used to analyze theoptimal design problem. The ACF cutting yield rate is selected to be objective function for optimization. The qualitycharacteristic function for yield rate is used in orthogonal particle swarm optimization. Three control factors such asplasma clean speed, ACF peeling speed and ACF cutter spring setting are selected to study the effect of the yieldrate. Results show that the proposed method can provide good optimal solution to improve the ACF cutting processfor TFTLCD manufacturing process.