Development methods for chemical amplification resist

Critical-dimension (CD) uniformity of the mask is the most critical issue for the quarter micron technology and below. Resist development methods, baking temperature uniformity and etching methods are very important parameters for the mask making to obtain good CD uniformity. New development systems which has a capability of applying several development methods for chemical amplification resist (CAR) was developed. The CD uniformity characteristics of three chemical amplification resists (CAR-A: negative, CAR-B: positive) were examined by using this system. In the experiments, a high-acceleration voltage electron beam system, a newly developed post exposure baking system, a precise metrology system and 6025 mask plates were used. The CD uniformity of CAR-B with conventional shower-spray development method gives worst CD variation than those of paddle development and dip development. It was also found that the development method which gives smaller damage on the resist layer gives smaller CD variation. The minimum CD variation was 16 nm in 3 (sigma) . The CD distributions in a mask plate were dependent on the resist materials. It also depends on other factors such as resist thickness, bake temperature and so on. By the optimization of these parameters, there are possibilities to obtain much smaller CD variations in a mask plate.