New Chemical Formulation and Its Use in Lift-Off Technology
Original Publication Date: 1983-Sep-01
Included in the Prior Art Database: 2005-Feb-07
In the semiconductor industry it is very often desirable to delineate an aluminum interconnecting pattern at the surface of a semiconductor structure. Subtractive etching has been used for a long time; however, in view of its limitations such as poor definition, it is more and more often replaced by so-called lift-off technology. When aluminum is used as the interconnecting metal, the lift-off operation takes a very long time and the results are generally not reproducible. At present, the basic compound for this step is N-methyl pyrrolidone, and a standard etch process might read: N methyl pyrrolidone (135ŒC) 1 to 10 hrs. N " " Œ (20 C) 10 min. Acetone 6-10 min. RP Œ (95 C) 10 min. 1332* Acetone (three times) 5 min.