静圧シール型真空ピンチャックの開発

概要

論文の詳細を見る
The next generation of lithography with ArF eximer lasers will decrease the focus depth to ±0.5μm. A chucking error of less than 0.03-0.05 μm in a 30-mm-squae field must therefore be achieved, excluding the region 2 mm from a processed wafer edge. A new static-perssure seal-type vacuum pin chuck whose vacuum seal extends beyond the wafer edge has been developed. This paper describes the chuck structure, the pin characteristics, and the flattening ability around the wafer periphery, which was calculated by the finite element method. Experimental results for 4 and 8-inch wafers agree roughly with the calculations. The diameter of pins made of pore-free ceramics is smaller than that of those made of alumina ceramics. As the hardness of the pore-free ceramics is almost half, pin corners are not irregular. These features greatly reduce the influence of dust and scratching. The flattening ability with the static-pressure-seal-type chuck is two times better than that with the ring-seal-type chuck in spite of the low vacuum pressure of-78 kPa. The allowable process-induced concave bow for a 775-μm-thick standard 12-inch wafer is 600μm when a chuck whose seal extends 1mm inside from the wafer edge is used.
公益社団法人精密工学会の論文
2003-06-05