Automatic Inspection System Design for Wire Bonding

• Main Author: 周正全
• Other Authors: 彭德保
• Format: Others
• Language: en_US
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/58469863939722412446

博士 === 國立交通大學 === 工業工程與管理系所 === 95 === Wire bonding is the process that makes the connection between the IC chip and the substrate. The minimum diameter of a bonding wire, which appears as a 3D loop in an IC chip, is about 20 μm. This kind of bonding wire easily bends or sags in the middle segment. Bonding wire defects can be classified as 2D-type and 3D-type. The 2D-type defects include broken, lost, shifted or shorted wires. These defects can be inspected from a 2D top-view image of the wire. The 3D-type defect is wire sagging, which is difficult to be inspected from a 2D top-view image. In this dissertation, a structured lighting system was designed and developed to facilitate all 2D and 3D-type defect inspection. The devised lighting system can be programmed to turn the structured LEDs on or off independently. For the 2D-type defect, the lighting system can provide light in proper incident angle to illuminate the bonding wire and the position of bonding wire will be represented in the image clearly. For the 3D-type defect, we supplant the traditional height measurement by the slope inspection. The structured lighting system can provide light in proper incident range and the variance of slope, the sagged wire segment, will be highlighted in a 2D image. Experiments show that the devised illumination system is effective and robust for wire bonding defect inspection. We developed a fast and robust set of machine vision algorithms for wire bonding inspection. The defect of a bonding wire being broken, lost, shifted, shorted or sagged in an IC chip can be inspected automatically. Some illustrations are given to show the efficiency and effectiveness of this proposed novel wire bonding vision inspection system.