Three-dimensional micromachining for microsystems by confined etchant layer technique

The micromachining of GaAs with three different truly three-dimensional (3D ) molds were performed by the confined etchant layer technique (CELT). The etched patterns were found, approximately, to be the negative copy of the 3 D molds. The general comparison of CELT with the existing micromachining te chniques, such as two-dimensional (2D) projection lithography and electro-d ischarge machining, was made. The replication of the complex microstructure s down to micrometer scale has been done by CELT in a single step. The phot oresist layer, together with the procedures of exposure, developing and rem oval of resist, could be eliminated. The advantages of CELT over the existi ng lithography techniques and its potential applications are discussed brie fly. It has been shown that CELT could be developed as a complementary tech nique to the existing micromachining techniques in fabricating microdevices for microsystems. (C) 2001 Elsevier Science Ltd. All rights reserved.