Failure analysis of die-attachment on static random access memory (SRAM) semiconductor devices

Different combinations of the SRAM die and the substrates to yield a better die-attachment are studied. Cleanliness of die backside, plasma etching of contaminated die backside, new frames and old frames are the factors considered. The number of rejects due to die cracking in the die-attachment can be minimized if (1) production die and new frames are used, (2) 100% eutectic coverage is performed, (3) no gold preforms is added for substrates that are already coated with a thin layer of 98% Au-2% Si and (4) plasma etcher is used in clean surface preparation for suspected contaminated die backside surfaces. To whom correspondence should be adressed.