Optimization of the temperature distribution across stencil mask membranesunder ion beam exposure

The pattern placement accuracy of a stencil mask is affected by thermomecha nical distortion induced during ion beam exposure. Any temperature gradient across the mask membrane could result in thermal distortions which contrib ute to the stringent error budget. Therefore, a concept has been proposed t o control the temperature across the mask membrane by using radiation heat transfer between exposure station components. This work extends previous ef forts by including the effects of the backside radiation loss of the exposu re area, the aperture, etc. Here the exposure station which has been propos ed by IMS-Ion Microfabrication Systems is investigated and simulated with f inite element models. Parametric studies have been performed in order to op timize design variables such as material properties, and the temperature se ttings of the cooled lens electrodes and aperture. (C) 1998 American Vacuum Society. [S0734-211X(98)03406-4].