Title :
Characterization of molybdenum thin films for micromechanical structures
Author :
Brown, Richard ; Ger, Muh-ling ; Nguyen, Tri
Author_Institution :
Dept. of Electr. Eng. & Comput. Sci., Michigan Univ., Ann Arbor, MI, USA
Abstract :
Characteristics of sputter-deposition, patterning, and sacrificial-layer etching for the formation of free-standing molybdenum structures are described. Stress measurement, etching, and deposition techniques are discussed. It is shown that sacrificial layer material has a strong influence on residual stress, and that long sacrificial layer etching times degrade film quality. For these reasons, aluminum is superior to SiO2 as a sacrificial layer for molybdenum. Appropriate wet and dry etching processes have been developed for patterning molybdenum and for removing the sacrificial layer. It is found that sputtering current and speed of rotation have little effect on film stress. These and other parameters are characterized so as to give control of film stress as deposited. X-ray diffraction measurements have revealed that the orientation of metal grain is determined by the direction of wafer rotation under the sputtering target
Keywords :
X-ray diffraction examination of materials; aluminium; etching; molybdenum; sputter deposition; sputtered coatings; stress measurement; Al; Mo-Al; X-ray diffraction measurements; dry etching; etching times; film quality; metal grain; micromechanical structures; patterning; residual stress; sacrificial-layer etching; speed of rotation; sputter-deposition; sputtering current; stress measurement; wafer rotation; wet etching; Aluminum; Degradation; Dry etching; Micromechanical devices; Residual stresses; Sputter etching; Sputtering; Stress control; Stress measurement; Transistors;
Conference_Titel :
Micro Electro Mechanical Systems, 1990. Proceedings, An Investigation of Micro Structures, Sensors, Actuators, Machines and Robots. IEEE
Conference_Location :
Napa Valley, CA
DOI :
10.1109/MEMSYS.1990.110253
