METHOD FOR MANUFACTURING SEMICONDUCTOR DEVICE PREVENTING THINNING OF THICK GATE OXIDE LAYER IN DUAL GATE OXIDE LAYER

摘要

PURPOSE: A method for manufacturing a semiconductor device is provided to improve GOI(Gate Oxide Integrity) and HCE(Hot Carrier Effect) by preventing thinning of a thick gate oxide layer in a dual gate oxide layer. CONSTITUTION: A first gate structure including a thick gate oxide layer(37a) and a first gate electrode(37a), and a second gate structure including a sacrificial gate oxide layer and a sacrificial gate electrode are simultaneously formed on a substrate(31) defined by a thick oxide region(I) and a thin oxide region(II). A spacer(39) is formed at both sidewalls of the first and second gate structure. A first interlayer dielectric is formed on the resultant structure. A trench is formed by selectively etching the interlayer dielectric on the second gate structure. A thin gate oxide layer(47) is formed on the bottom of the trench. A second gate electrode(49a) is formed on the thin gate oxide layer. Then, a second interlayer dielectric(51) is formed on the resultant structure.