An optical photo lithography based 0.15µm GaAs PHEMT process and 2mil-substrate technology that enables high production throughput and low cost is described. The developed process achieved Imax=575mA/mm, BVgd=14V, and 753mW/mm of output power density at P-1 condition at 18GHz. Design and test results for DC to 85GHz traveling wave amplifier (TWA) and 29-30.5GHz 4.9W power amplifier (PA) are also described as process capability verification. TWA shows 8dB of small-signal gain and 12dBm of output power up to 85GHz frequency. PA shows 20dB of small-signal gain and 36.9dBm of output power at 3dB gain compression condition in between 29 and 30.5GHz frequencies. These results verify the process capability to manufacture MMIC devices for applications up to 90GHz.