SEM/TEM of the Month
Staff -- Semiconductor International, 1/1/2002
This SEM from AIC Semiconductor Sdn Bhd shows the remains of a eutectic Pb-Sn solder bump on a silicon die after chemical etching. The large dendrite on the pad is the Pb-rich phase of the solder, which grew as a result of thermal aging, said Michael Raj Marks of AIC's Package Development Department. Au-Sn intermetallic compound nodules on the pad surface were formed because of the reaction between the Ti-Ni-Au upper bump metallization (UBM) that originally covered the pad, and the bulk solder.
Please send submissions for SEM/TEM of the Month to Peter Singer, Editor-in-Chief, 58 Summer St., Andover, MA 01810 USA. E-mail: sieditor@aol.com
