A HIGH YIELD PROCESS FOR DELICATE WAFERS
Original Publication Date: 1986-Oct-01
Included in the Prior Art Database: 2001-Oct-22
The processing of thin or delicate wafers is often hampered by excessive wafer breakage during the fabrica- tion process resulting in greatly reduced yields. This is especially true for optoelectronic device wafers of InP and GaAs because they are both fragile and thin (.002" - .OOW'). The process presented here minimizes the break- age of wafers during the fabrication process by utilizing a two wax bonding scheme where the wafer is attached to the submount using a high melting point wax which permits further attachment to the lapping and polishing fixtures with a lower melting point wax so that the wafer does not need to be removed from the submount. The melting point of the high temperature wax is sufficiently high so that the temperature cycles used in nor- mal photoresist processing are not an issue at the later steps in the process. The submount provides the mechan- ical support necessary for the wafer during the high breakage steps (i.e. lapping, polishing, alignment, etc.).