Method for forming a DRAM semiconductor device with a sense amplifier

A method for forming a sense amplifier of a semiconductor device comprising the steps of:

• providing a semiconductor substrate having an NMOS and a PMOS for a sense amplifier formed on the substrate, a P+ pickup and an N+ pickup formed on the substrate between the NMOS and the PMOS in the shape of parallel bars, and an insulation layer formed on the substrate between the NMOS and the P+ pickup, between the P+ pickup and the N+ pickup, and between the N+ pickup and the PMOS so that a portion of the insulation layer formed between the P+ pickup and the N+ pickup is bridged to a portion of the insulation layer formed in other regions;
• forming an insulation interlayer on the insulation layer so as to cover the NMOS, the PMOS, the P+ pickup, and the N+ pickup;
• etching the insulation interlayer so as to form contact holes for exposing a junction region of the NMOS, a junction region of the PMOS, the P+ pickup, the N+ pickup, and gates, respectively;
• forming a mask pattern on the substrate, the contact holes being formed on the substrate, the mask pattern having hole-type openings for selectively exposing the contact holes in the junction region of the PMOS and in a region of the P+ pickup;
• performing ion implantation of a P-type impurity in the junction region of the PMOS exposed by the contact holes and in the region of the P+ pickup exposed by the contact holes by using the mask pattern as an ion implantation barrier;
• removing the mask pattern;
• cleaning the substrate, the mask pattern having been removed from the substrate;
• and
• forming bit lines on the insulation interlayer so as to fill the contact holes.