Pressure indicating film characterization of pressure distribution in eutectic Au/Sn wafer-to-wafer bonding

摘要

Purpose - The purpose of this paper is to characterize pressure non-uniformity in a wafer-to-wafer bond chamber using pressure sensitive paper.Design/methodology/approach - Pressure non-uniformity in a wafer-to-wafer bond chamber is characterized using pressure sensitive paper. Theeffect of poor pressure uniformity is discussed, and the non-uniformity corrected for use in a eutectic Au/Sn based wafer-to-wafer bond. Findings - Several types of under solder metallization were also investigated, with Nb/Au seed metal providing the best overall result with good soldercompression, liquid proof seal and minimal solder spill-out. Solder compression versus pressure applied was studied to achieve an excellent gap control(2-3 μm) between the bonded substrates. Originality/value - This paper shows that characterization of applied pressure measured directly at the substrate is an important aspect in thedevelopment of high yielding bond processes.