Fast Image Alignment for Inspection of FCB Bump Coin System

Sungho Suh,Hansang Cho

doi:10.12792/iciae2015.100

Abstract

FCB Bump Coin System is a machine that makes the bump height on the front side of FCB (Flip Chip Ball Grid Array) PCB uniform by pressing with high temperature and pressure vessels. In the process of pressing, defects such as scratches in SR (Solder Regist) area, breakages in MLCC (Multi Layer Ceramic Capacitor), etc. can occur on the backside of the product. FCB bump coin system inspects for defects on the backside of the product. It is essential for the inspection algorithm in the system to align inspection images with reference image. For fast and accurate inspection, the alignment algorithm is the most crucial element. And the image size the system provides is 4072x 3096 for which widely used methods take much time to process due to its big size. This paper introduces a method of fast image alignment for inspection of FCB bump coin system. It includes a global alignment method and a specific area selection method for fast image alignment. While the proposed method is simple, the experiment shows that it gives a fast and accurate image alignment result for FCB bump coin inspection.

Highlights

Image alignment is the process of finding the correspondence between the original reference image and the target image
To avoid the long processing time and inaccurate results, this paper proposes the fast image alignment method for FCB bump coin system inspection
The rest of this paper is organized as follows: We propose the fast image alignment method which is suitable for FCB bump coin system inspection

Summary

Introduction

Image alignment is the process of finding the correspondence between the original reference image and the target image. It cannot be known which specific area should be inspected for MLCC breakages or SR scratches. If all of these areas are aligned with inspection images by the template matching method[8], it takes much time to align the images It cannot meet the required processing speed of the bump coin system inspection. To avoid the long processing time and inaccurate results, this paper proposes the fast image alignment method for FCB bump coin system inspection. The rest of this paper is organized as follows: We propose the fast image alignment method which is suitable for FCB bump coin system inspection. We show the experiment result by comparing our proposed method to other methods, and conclude our paper as well as describe future work

Global Alignment between the Reference Image and the Inspection Image

Experimental Result

Conclusion