Improving the Yield and Reliability During the Production of Monolithic Integrated Circuits
Original Publication Date: 1984-Mar-01
Included in the Prior Art Database: 2005-Feb-03
During the production of monolithic integrated semiconductor circuits, ohmic contact 1 to silicon 2 is produced by means of a mask 3. Semiconductor technologies for high integration densities use a double layer, for example, Si3N4 on SiO2, as mask material for defining the geometry of contact 1. During the etching of the contact hole 4 (Fig. 1), a window 5, etched into the Si3N4 layer, serves as an etching mask for the SiO2 layer. This step produces an overhang 6 of the Si3N4 layer over the SiO2 layer. Ohmic contact 1 is produced by vapor depositing a contact metal 8, using a photoresist mask 7 applied to the Si3N4 layer. Upon application of photoresist mask 7, residues 9 of the photoresist penetrate below the nitride overhang 6 of the contact hole 4.