Semiconductor device and manufacture thereof

Abstract

Abstract PURPOSE:To obtain a groove-type capacitor large enough in capacitance without providing a deep groove by a method wherein a groove is provided, whose diameter in the direction of its depth is larger than the diameter of its opening. CONSTITUTION:A SiO2 film 3 is bored applying a resist mask 4 and a groove 5 is made through a RIE. An SiO2 film 6 and a CVD SiN film 7 are laminated on the inner wall. Resist is buried in the groove 5 and subjected to development controlling the exposure to light rays so as to leave a resist 8 at a lower part. The upper parts of the SiO2 film 6 and the Si3N4 film 7 are removed through etching and then coated with a SiO2 film 3'. A SiO2 film 6' and a Si3N4 film 7' left as the lower part are made to be removed through etching to expose a substrate 1. Next, a trench groove 5' can be obtained through an isotropic etching, whose inner diameter l2 is larger than its diameter l1 at the opening. The inner wall 5' is coated with a SiO2 film 3''', and then a poly-Si layer 9, an insulating film, and a poly-Si opposed electrode layer 11 are formed. By this constitution, a groovetype capacitor large in capacitance can be obtained without making the groove deep.

Inventors

• 👤 Masataka Kase

Bibliographic Details