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URN etd-1030115-222727
Author Chun-Hsien Ou
Author's Email Address sai0033x@gmail.com
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Department Mechanical and Electro-Mechanical Engineering
Year 2015
Semester 2
Degree Master
Type of Document
Language zh-TW.Big5 Chinese
Title FE Analysis for PBGA and Optimization of Laser Dicing for QFN Package
Date of Defense 2016-07-27
Page Count 90
Keyword
  • Response surface method
  • Finite element analysis
  • Taguchi method
  • Laser dicing
  • Abstract In this study, the optimal parameters focuses on decreasing the stress difference between two materials and increasing productivity and yield. The size of Quad Flat No leads (QFN) packaging are getting smaller, and laser dicing also gradually replaces the diamond cutting to avoid delamination. Therefore, Taguchi method and Analysis of variance (ANOVA) are used to determine the optimal parameters in the laser dicing, and surface of dicing path is analyzed by Energy-dispersive X-ray spectroscopy (EDS). Different material plating are diced by different laser wavelength and the dicing results are compared in the this study. There are many re-depositions in the dicing path after laser dicing because the carbon compound reacts with other element. The carbon content in Ultraviolet (UV) laser dicing packaging is smaller than Infrared (IR) laser. The IR laser has the same dicing situation between different materials, but the UV laser would decrease dicing effectiveness when dicing harder materials. The different shrinkages rate of two materials lead to discontinuous stress in high temperature and high molding pressure Ball Grid Array (BGA) process, therefore this study carries out finite element analysis to improve the processing. From Taguchi experiment method and ANOVA, the optimal parameters of IR laser are 90 mm/s for speed, 90 times for pass, 80 kHz for frequency, and 60 % for power, and the most significant contribution of factor is speed with 36%. The optimal parameters of UV laser are 90 mm/s for speed, 90 times for pass, 65 kHz for frequency, and 70% for power, and the most significant contribution of factor is speed with 38%. From simulated results, the optimal parameters of uniform design are 31.7 MPa for molding pressure, 171.61°C for temperature, and 358.33 μm for shoulder width. The best parameters of response surface method are 42.57 MPa for molding pressure, 185°C for temperature, and 800 μm for shoulder width. The two experimental methods have different trends. According to real products, the interaction exists in factor of processing, so the response surface method is more accurate than the uniform design.
    Advisory Committee
  • Chi-Hui Chien - chair
  • Zong-Hsin Liu - co-chair
  • Y. J. Chen - co-chair
  • Yeong-Maw Hwang - co-chair
  • Cheng-Tang Pan - advisor
  • Files
  • etd-1030115-222727.pdf
  • Indicate in-campus at 1 year and off-campus access at 2 year.
    Date of Submission 2016-08-09

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