An Automatic Bump Detecting System for LCD COG Module Using Fuzzy Reasoning

The Chip-on-Glass (COG) package, which assemblies the driver IC onto a glass substrate with Anisotropic Conductive Film (ACF), is mainly used in the Liquid Crystal Display (LCD) module. With the higher demand of display capacity, the stability of COG interconnection under fine pitch package becomes more important and difficult. Interconnection test and bump microscopic inspection are commonly used to confirm the viability of the interconnections, and are accomplished manually by engineers, which are repetitious and can merely give out the conductive particle numbers in rough. According to the existent ACF-COG interconnection resistance models, the conductivity of bump and pad can be quantitatively analyzed with the conductive particle contact area. In order to implement an automatic system for the bump microscopic inspection to count the particle number and achieve the distribution of contact areas, it is necessity to realize the bump detecting and extracting automatically. In this paper, an automatic bump detecting system using fuzzy reasoning is proposed, and can perform the bump image extraction with a high accuracy. With this system, the particle contact areas and conductive particle number can be analyzed automatically.