EFFECT OF ADDITIVE GASES ON DIMENSION CONTROL DURING CL-2-BASED POLYSILICON GATE ETCHING

In order to minimize the pattern transfer difference (PTD) between a d ense cell pattern and isolated pattern, we investigated the effects of additive gases (O-2, HBr, and N-2) and bias power in Cl-2-based polys ilicon gate etching. When the flow rate of N-2 was increased, a lager PTD was due to a marked increase in the critical dimension bias in the isolated pattern. The PTD was also influenced to a large extent by th e bias power. When the bias power was increased, there occurred a line ar increase of the PTD in Cl-2/N-2 plasma, which also exhibited a stri king dependence on the bias power in Cl-2/HBr plasma; however, in Cl-2 /O-2 plasma, the PTD showed no notable the dependence on bias power, F rom these data, it is proposed that the PTD between the two may be due to the ion scattering and polymer build-up difference.