^7fThe molding process with Clear Epoxy Molding Compound (CEMC) becomes more rampant due to the increasing application of optical/opto-electronic packages. Due to high coefficient of thermal expansion (CTE) and high mold shrinkage of the CEMC, the thermal mismatch between CEMC and leadframe causes more warpage compared to the traditional epoxy molding compound especially in map QFN packages. Such package warpage after molding is one of the critical issues in the QFN manufacture which should be controlled in order to pass the back end process (e.g. sawing). This paper will discuss approaches developed to reduce warpage of the packages molded with CEMC. One technique is to control the profiles of cooling and post mold cure process. The warpage can also be reduced by assigning the designed package/leadframe with easy stress relief capability. The warpage performance of CEMC molded at different temperature shows that high Tg, low CTE and low molding temperature are the direction for compound composition study.
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