Title :
Metal film protection of CMOS wafers against KOH
Author :
Munch, U. ; Brand, O. ; Paul, O. ; Baltes, H. ; Bossel, M.
Author_Institution :
Phys. Electron. Lab., Eidgenossische Tech. Hochschule, Zurich, Switzerland
Abstract :
This paper reports a new protection for the front side of fully processed CMOS wafers against KOH etching solutions. The protection is based on thin TiW and Au films and is fully CMOS compatible. No mechanical fixture is required during the anisotropic etching step. Therefore, the new method is excellently suited for batch micromachining. Up to 100% of all chips on 6 inch wafers were fully operational after 4 hours KOH etching. The membrane yield after KOH etching was 100% and nearly 90% after the not yet optimized removal of the protection films. Thus, this protection fulfils the requirements of inexpensive and reliable sensor production
Keywords :
CMOS integrated circuits; diffusion barriers; electroplating; etching; micromachining; KOH etching solutions; anisotropic etching; batch micromachining; chip yield; diffusion barrier; etch rate; front side protection; fully processed CMOS wafers; membrane yield; metal film protection; plating seed layers; reliable sensor production; Aluminum; Biomembranes; CMOS process; Etching; Fixtures; Gold; Micromachining; Production; Protection; Resists;
Conference_Titel :
Micro Electro Mechanical Systems, 2000. MEMS 2000. The Thirteenth Annual International Conference on
Conference_Location :
Miyazaki
Print_ISBN :
0-7803-5273-4
DOI :
10.1109/MEMSYS.2000.838587
