Technique For In-Situ Or Real-Time Monitoring Of Contact Hole Etching In Silicon Technology
Original Publication Date: 1979-Nov-01
Included in the Prior Art Database: 2005-Feb-20
In MOSFET and monolithic bipolar technologies, it is always necessary to obtain electrical contacts to various n- and p-regions by opening contact holes to these regions. Sometimes, such as in the case of VMOS fabrication, contacts must be made by vertical etching through various n- and p-layers. A revolutionary blanket diffusion technique can be applied in monolithic bipolar technology if it is possible to make contacts to 'covered' or 'buried' n- and p-regions by vertical etching. The difficulty in vertical etching to contact buried regions lies in the precise control of etching depth considering, for example, the fact that the base region of a bipolar device is typically 2000 Angstroms thick.