Inventors:
Philip E. Mauger - Santa Clara CA
Alex R. Shimkunas - Palo Alto CA
Junling J. Yen - Cupertino CA
Assignee:
Nanostructures, Inc. - Mountain View CA
International Classification:
H01L 21306
B44C 122
C03C 1500
C03C 2506
Abstract:
A high resolution shadow mask with low pattern distortion is formed from a silicon membrane with a pattern of apertures etched through the membrane by reactive ion etching using a silicon dioxide masking layer. To achieve low distortion over a large area membrane, the stress of the membrane and the masking layer is controlled to remain within an optimal range so that the stress relief that occurs when the apertures are formed is kept negligibly small. A silicon membrane with controlled stress is made using a p/n junction electrochemical etch-stop process. After making the membrane, it is then coated with a deposited silicon dioxide layer. The stress of the oxide layer may be adjusted to an optimum value by annealing after deposition. The membrane with the oxide mask layer is next coated with a photoresist layer which is then patterned with the desired shadow mask pattern. Once the photoresist is patterned, the pattern is then transferred into the oxide layer by reactive ion etching.