Feasibility of Using Adhesion Force as a Parameter for IC Package Mold Design

• Main Authors: Hwe-Zhong Chen, 陳暉長
• Other Authors: Huei-Huang Lee
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/32868971228118165707

碩士 === 國立成功大學 === 工程科學系碩博士班 === 94 === In integrated circuit (IC) packaging, when epoxy molding compound (EMC) is filling the mold cavity and cured in the mold, adhesion effects occurs in the interface between EMC and mold surface. Adhesion effects can cause many problems. For example, too large an adhesion force may damage an IC during ejection and causes the package to fail and thus lower the yield rate and reliability. To get rid of the mold adhesion problems, improving the mold design and applying suitable surface treatments such as mold surface coating are the common approaches. Applying suitable surface coating approach is a more popular and practical approach. How to reduce the mold adhesion force and improve products yield rate are the main issues for packaging. This research uses a semi-automatic EMC adhesion force test instrument that had been developed and fabricated to measure normal and shear adhesion force between the mold surface and EMC. By measuring the adhesion force, one can judge how much does a specific type of surface treatment help in reducing the amount of mold adhesion force. One will use this instrument to measure the magnitude of adhesion force between EMC and nine kinds of various mold surface coating. And determine the most effectiveness of mold coating. This paper also discuss the issue of successive normal force test. One will use the most effectiveness of mold coating to execute the continuous normal adhesion experiment. The variation of normal force during successive molding test can be used to predict the time for mold cleaning. By wanting the total number of shots when the normal force begins to rise, one can accurately predict the number of shots for a specific kind of mold surface coating to be cleaned. This paper also describes that effects of defrosting period on mold adhesion force of EMC. Defrosting is a process to increase the frozen EMC temperature to room temperature and stay at room temperature for some time period before molding. It is found by molding engineers that increased defrosting time period will increase the frequency of mold cleaning. But there has been no quantitative description on how much mold adhesion force increase during the defrosting process. One can use a semi-automatic EMC adhesion force test instrument to evaluate the effects of defrosting period on mold adhesion force of EMC. By measuring the adhesion force, one can quantify how much adhesion force exists between EMC and the mold surface under different defrosting periods. The influence of moisture during defrosting on the adhesion force is also discussed. Finally, one can determine the best defrosting period of EMC.