Inexpensive and Efficient Backside Decapsulation Technique for Challenging Down Bond Devices

Abstract Backside decapsulation is necessary to be able to perform failure analysis on devices with dense metallization. However, for down bond devices with the down bonds located too close to the die edge, using the traditional chemical method tends to overetch the bonding wires, and using the precision milling tool is too time-consuming. In this paper, a new inexpensive and efficient method is developed for challenging down bond devices with the die attach pad (DAP) buried in the molding compound. This method uses laser to reduce the thickness of the whole die area molding compound first and then partially expose the DAP, which length and width are smaller than that of die area. Lastly, it uses a chemical method to remove the die DAP, and keep a measured thickness of the molding compound to protect the bonding wires from being over-etched.