Deflection Mapping is Useful for its Ability to Identify Distortion-prone GaAs Wafers
A U T H O R / C R E D I T S
Michael D. Gibson
TriQuint Semiconductor, Inc., 2300 N.E. Brookwood Parkway
Hillsboro, Oregon 97124
A B S T R A C T
Deflection Mapping is a valuable technique in its ability to recognize distortion-prone SI-GaAs wafers. This method was entertained for the purpose of characterizing wafer distortion, after the number of stepper misalignments increased in photo-lithography, and the nature of the misalignments suggested the Rapid Thermal Anneal (RTA) process was the root cause. Not only did Deflection Mapping prove useful in addressing distor-tion at the unit process, it helped characterize distortion-prone boules. More importantly, it helped identify an unknowing sup-plier of distortion prone ingots. The metric that Deflection Mapping provides is now instrumental in qualifying tools and matching multiple RTA's to one another.