METHOD FOR FORMING CONTACT OF SEMICONDUCTOR DEVICE

摘要

PURPOSE: A method for forming a contact of a semiconductor device is provided to reduce a device failure due to poly stringer in a modified plug self aligned contact process. CONSTITUTION: A spacer nitride is formed on sidewalls of a word line on a substrate(1). Next, a barrier nitride(4) and a doping barrier(5) are deposited over all surfaces, and an interlayer dielectric(6) is subsequently formed thereon. The interlayer dielectric(6) and the doping barrier(5) are then polished until the barrier nitride(4) above the word line is exposed. Next, an oxide layer(8) and an anti reflection coating(ARC) layer(9) are successively deposited and etched through a photoresist mask formed thereon. After removing the photoresist mask, the barrier nitride(4) is etched by using both the oxide layer(8) and the ARC layer(9) as a mask. Contact holes are therefore formed to partly expose the substrate(1). A plug polysilicon(14) is then deposited and subsequently subjected to a first chemical mechanical polishing(CMP) process using a slurry for polysilicon and a second CMP process using a slurry for oxide. A poly stringer produced in the first CMP process is removed in the second CMP process.