The establishment of standard resist processes are a primary requirement for the X-ray Lithography National Test Bed at the Center for X-ray Lithography. For this, experimental design is a necessary component of the methodology given the large parameter space associated with chemically amplified resists (CARs). The process development is carried out in three phases. DOX is applied to several steps in the development. The vacuum hot plate pre-bake, post-bake time, temperature and the exposure dose have the greatest effect on controlling the performance of the resist. Constraints are placed on the contrast, develop time and unexposed resist loss. The exposure dose needed to meet these requirements is obtained from the modified response surface of the bulk behavior. The final optimization is based on the CD control and side wall angle for quarter-micron features in resist. The process is run on a sampled basis in order to determine the control issues. Control limits are set from these data, and the process performance is determined.
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