Manufacture of non-voltage semiconductor memory device

Abstract

Abstract PURPOSE:To acquire a desired gate length by substantially enlarging an etching mask for isolating and forming a control gate through a technique wherein the side walls are left and by carrying out anisotropic etching and isotropic etching thereafter. CONSTITUTION:A nitride film 12 is made to remain as an etching mask only on the sidewall of an oxide film 11. A second layer polycrystalline silicon film 6 is etching by using an etching mask consisting of the oxide film 11 and the nitride film 12 to isolate and form a control gate. Then, a second gate insulating film 5 is etched, and a first layer polycrystalline silicon film 4 is etched to isolate and form a floating gate which is self-aligned to the control gate. The second layer polycrystalline silicon film 6' which remains on a step section is etched and removed by isotropic etching. The control gate and floating gate are simultaneously etched in a transverse direction at an etching amount of about a thickness of the nitride film 12 formed at the sidewall of the oxide film 11 through sidewall remaining. Then, a source/drain diffusion layer 7 is formed, an interlayer insulating film is formed, and a wiring such as a bit line is formed.

Inventors

• 👤 Yoshihisa Iwata
• 👤 佳久 岩田
• 👤 Ryozo Nakayama
• 👤 中山　良三

Bibliographic Details