Method of manufacturing decoder circuit

A method of manufacturing a semiconductor integrated circuit device comprising the steps of:

• (a) preparing a semiconductor substrate of a first conductivity to which has a principal surface,
• said semiconductor substrate including, at least, a first region in which memory cells are to be formed, and a second region in which a decoder circuit for reading out information of said memory cells is to be formed;
• (b) forming on the principal surface of said second region a plurality of selector switch elements for selecting decode signal lines in accordance with address signals received from pairs of complementary address signal lines, each pair including a true line and a bar line,
• said each selector switch element being configured of a first MISFET of said first conductivity type and a second MISFET of second conductivity type opposite to said first conductivity type, gate electrodes of said first and second MISFETs being unitarily formed of a first conductor film of identical layer and constructing an input terminal of said selector switch element;
• (c) forming a first insulator film on said selector switch elements;
• (d) removing selected parts of said first insulator film on the input terminals of said selector switch elements, thereby to form first contact holes;
• (e) forming on said first insulator film, members of a second conductor film which are electrically connected to the respective input terminals through the corresponding first contact holes and each of which is extended to under regions where the corresponding true and bar lines are to be formed;
• (f) forming a second insulator film on the second conductor film members;
• (g) forming second contact holes in said second insulator film on said second conductor film so as to reach said second conductor film;
• and
• (h) forming a third conductor film of said second insulator film and subsequently patterning said third conductor film, thereby to form said true lines and said bar lines on said second conductor film, and simultaneously to electrically connect either of said true lines and said bar lines to said second conductor film members through the corresponding second contact holes.