Abstract: A method of forming photomasks is described which provides good critical dimension control for critical pattern elements and provides good throughput and low defect levels for etching relatively large areas of opaque material. The pattern is first modified to form a frame around the pattern elements which require good critical dimension control. The opaque material, such as chrome, in this frame is then etched away using dry anisotropic etching. The dry anisotropic etching provides good critical dimension control. The remainder of the opaque material to be removed is then etched away using wet isotropic etching. The wet isotropic etching provides good defect control in this region of the mask and good throughput. This method provides good critical dimension control at the edges of the pattern elements, good throughput in mask fabrication, and good defect level control in removing the relatively large areas of opaque material which do not affect critical dimension control.