JPS5799743A - Apparatus and method of plasma etching - Google Patents

Abstract

PURPOSE:To achieve a high-accuracy working under a relatively high vacuum using a plasma etching apparatus by a method wherein a No.1 cathode and a No.2 cathode which is a plate with through-holes are disposed facing to each other with vertical arrangement in a cylindrical anode, and a magnetic field is generated between both cathodes to etch a specimen held under the No.2 cathode. CONSTITUTION:Inside a quartz, for example, tube 1, a pair of parallel electrodes 2 and 3 and a stainless cylindrical electrode 4 are arranged to form a main discharging region (shaded part). An electrode 3 is of a ring shape or is a plate with many through-holes. A specimen 8 is held on a holder 5 installed outside the main discharging region facing the electrode 3. For example, in etching a silicon substrate with a resist mask, electrodes 2 and 3 are grounded, the electrode 4 is, for example, at 600V, and a magnetic flux of 450 Gauss, is generated with a coil 6. Introducing CF4 gas into the tube, plasma etching is implemented at the vacuum of 10<-2>torr. By applying an external magnetic field in such a way, discharge at a high-vacuum area is feasible. Further, since etching by ions is also effective, an almost vertical etching characteristic can be obtained, so a minute pattern can be achieved in a high accuracy.