METHOD FOR MANUFACTURING SEMICONDUCTOR DEVICE

PROBLEM TO BE SOLVED: To provide a method for manufacturing a semiconductor device capable of preventing the resistance to hot carriers from degrading. SOLUTION: This method comprises the steps of forming a field oxide film 12, gate oxide films 13a, 13b, and gate electrodes 14a, 14b on a semiconductor substrate 11; forming a first diffusion layer n, in an element region of a normal transistor 2 and an element region of a high breakdown strength transistor 1; coating the surface of the semiconductor substrate 11 with an oxide film 16; coating the high-breakdown voltage transistor 1 with a photoresist R3 as a mask; thereafter, forming a side wall 16s in the gate electrode 14b on the normal transistor 2 side by carrying out RIE in the oxide film 16; forming openings R4a in a photoresist R3 on the high breakdown voltage transistor 1 side and on the oxide film 16; carrying out ion implantation in the semiconductor substrate 11; forming a second diffusion layer n+, in the element region of the normal transistor 2; and carrying out ion implantation, from the opening R4a on the high breakdown voltage transistor 1 side, to form the second diffusion layer n+. COPYRIGHT: (C)2007,JPO&INPIT