HgCdTe third-generation infrared focal plane arrays such as avalanche photodiodes, two-color detectors and multi-color
detectors usually have mesa microstructures, which bring on huge challenge in device technology, especially coating
resist process and exposing process. Using conventional spinning coater technology, the thickness of different position in
the structure usually is incoordinate, the resist in the bottom of trench is often very thick, but the resist on the top corner
of trench is often very thin, sometimes may be nothing. Spray coater technology is a new resist coating technology,
which can make the resist equably distribute. The equipment we used is spin module Delta Alta Spray coater (AK
995023) produced by Suss Micro Tec. Through adjusting the parameters of the equipment, such as flux of resist, flux of
nitrogen, chuck temperature, arm speed, scan times and so on, we have obtained multifarious resist figure with diverse
thickness in order to satisfy different requirements. Now, we have already experimented three different mesa
microstructures, the resist thickness we have obtained can change from zero point five micrometer to five micrometers.
The pictures gained by scanning electronic microscope show that the resist have good uniformity, which increase the
maneuverability of exposure process which we will do next.