| 摘要 |
PROBLEM TO BE SOLVED: To stabilize the high resistance characteristics by eliminating the impurity diffusion in the high resistance part of a polysilicon for constituting the load resistor of the memory cell of an SRAM. SOLUTION: The interconnection structure of a semiconductor device and a second interconnection layer 5 made of a polycide structure are formed of poly-Si (high resistance) 5-1 and a metal silicide (low resistance) 5-b. At this time, to hold high resistance, no impurity is implanted in the polysilicon. The lower poly-Si is used as a high resistance to a first interconnection layer 2 via a through hole 4, and the upper metal silicide is used as a connecting low resistance interconnection from the high resistance to another interconnection. Accordingly, at the time of heat treating step, the resistance reduction due to the impurity diffusion to the high resistance interconnection part is low, and the characteristics are stabilized. The magnitude of the resistance can be controlled according to the poly-Si film, it is easy to obtain desired resistance. |
