Comprehensive Study on the Interactions of Multiple Die Shift Mechanisms During Wafer Level Molding of Multichip-Embedded Wafer Level Packages

• Published in: IEEE transactions on components, packaging, and manufacturing technology (2011) Vol. 4; no. 6; pp. 1090 - 1098
• Main Authors: Ho Siow Ling, Bu Lin, Chong Ser Choong, Velez, Sorono Dexter, Chai Tai Chong, Xiaowu Zhang
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 01-06-2014; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Adhesives; Assembly; Compounds; Computational fluid dynamics; Computational modeling; die shift; die shift mechanisms; embedded wafer level packaging (EWLP); finite element modeling (FEM); mold tape characterization; Numerical models; Semiconductor device modeling; Temperature; wafer level packaging; Computational fluid dynamics; mold tape characterization; finite element modeling (FEM); wafer level packaging; die shift; die shift mechanisms; embedded wafer level packaging (EWLP)
• ISSN: 2156-3950; 2156-3985
• DOI: 10.1109/TCPMT.2014.2316019

Comprehensive numerical and experimental analyses were performed to investigate the issue of die shift during the 12-in wafer level molding process of multichip-embedded wafer level packages. The proposed modeling methodology considers the major mechanical and mold flow mechanisms in the phenomenon. Experimental characterization of the adhesion behavior of a die attached on mold tape at molding temperature suggests that mold tape behavior is an important contributing factor to die shift and the mold tape behavior at high temperature needs to be considered for improved die shift prediction. Incorporating the characteristics of the mold tape adhesion behavior, the die shift obtained from the improved numerical model is compared with the experimental observations and a good correlation is observed. From the investigation, it was found that mechanical effects such as coefficient of thermal expansion of the mold plate and chemical shrinkage can contribute up to 85% of the die shift while fluidic force accounts for the rest.