As it is becoming clear that the 65nm node lithography would have no other alternative than "193nm" reinforced with all the possible RETs, "tricky" masks such as Alternating PSMs, Chromeless masks, or Enhancer masks might become inevitable. Most of the "tricky" masks will need the quartz substrate to be etched to give the phase shift. This means that an etching process without an etch-stop or an interface between different materials should be applied. We evaluated Qz etching process and optimized etching condition. Phase shift measurement system (λ 248 nm) and atomic force microscope were used for our measuring Qz depth and profile. And we can measure narrow space to 0.2 um size. As a result of optimized condition, Qz depth uniformity is 3sigma 1.5%, cross section is vertical sidewall and rectangular corner, and linearity error is 4.5% with isolated space and 9.0% at hole. And, we checked this linearity error does not affect so much to wafer printing, using aerial software simulation.