Abstract: A collet structure may include a holder, a plate and an absorption member. The holder may include a shank and a vacuum provider. The shank may include a first magnet. The vacuum provider may be positioned over the shank. The vacuum provider may include at least one first vacuum hole configured to transfer vacuum, which may be supplied from the outside, to a space under the shank. The plate may have a size substantially the same as a size of the shank. The plate may include a plurality of second vacuum holes connected directly and indirectly to the first vacuum hole. The absorption member may be attached to the plate. The absorption member may include a plurality of third vacuum holes connected directly and indirectly to the plurality of second vacuum holes.

Abstract: A method of plasma etching tungsten silicide over polysilicon particularly useful in fabricating flash memory having both a densely packed area and an open (iso) area requiring a long over etch due to microloading. Wafer biasing is decreased in the over etch. The principal etchant include NF3 and Cl2. Argon is added to prevent undercutting at the dense/iso interface. Oxygen and nitrogen oxidize any exposed silicon to increase etch selectivity and straightens the etch profile. SiCl4 may be added for additional selectivity.

Abstract: A method of plasma etching tungsten silicide over polysilicon particularly useful in fabricating flash memory having both a densely packed area and an open (iso) area requiring a long over etch due to microloading. Wafer biasing is decreased in the over etch. The principal etchant include NF3 and Cl2. Argon is added to prevent undercutting at the dense/iso interface. Oxygen and nitrogen oxidize any exposed silicon to increase etch selectivity and straightens the etch profile. SiCl4 as an example of a silicon and chlorine containing passivating gas may be added for additional selectivity.