The IC Laser Mark Quality Criterion And Optimization Of Laser Parameters

This thesis is based on the fiber laser marking system of IPG Technology Ltd. The laser mark quality criterion is analyzed and the optimal fiber laser marking parameters is obtained.Laser marking is one of the major alternatives for marking semiconductor packages aside from ink-based marking. It has been widely used to write directly onto the surface of integrated-circuit (IC) devices.In this thesis, the process of marks produced by fiber laser is analyzed. Based on the character of the laser marks, the method of the digital image process is chosen. After the information of mark is obtained, the statistical theory is used to analyze how clear the laser marks are. Utilized the quality criterion, the grey relational analysis is used to optimize the fiber laser marking system.Generally speaking, the thesis includes the following parts:①Analyze the laser marking process on IC packages.②Obtain the digital images by CCD camera.③Preprocess the digital images and get the samples in order to the template.④The statistical characters are obtained by the template and compute the contrast, variance and skewness.⑤Optimize the fiber laser marking system parametersThe quality criterion in this thesis validates to the actual laser marks and the better laser marks are obtained by optimal laser parameters. The conclusions in this thesis have the definite referenced value for the laser markers of IC packages in actual industrial productions.