A self-aligning contact process for MOS LSI

A Self-Aligning Contact (SAC) process, which easily forms contact holes on fine patterns and yields flat device surfaces, is proposed. Several new techniques which are necessary for the SAC process are established by using a process evaluation test element groups pattern for total process evaluation. In particular, a plasma-reactive-sputter etching technique makes it easy to etch double layer of nitride and polysilicon and simplifies the SAC process as well as the conventional MOS process. The new MOSFET structure realized by the SAC process has the advantage of smaller short-channel effect and can be applied to short-channel MOS LSI's. The high potential of the SAC process for future fine-pattern MOS LSI processes is verified by the good yield and high performance of the 1K RAM's fabricated.