| 摘要 |
1286219 Etching NATIONAL CASH REGISTER CO 28 May 1971 [2 July 1970] 17725/71 Heading B6J An N-type silicon semiconductor wafer 10, Fig. 3, has formed thereon by oxidation a silicon dioxide layer 15 formed thereon and formed with windows to expose p-type regions of the wafer. An aluminium film 20 is evaporated on to the layer 15 and the exposed regions of the wafer. A photoresist is deposited on the film 20, and selectively removed by a solvent after exposure to ultraviolet radiation through a mask. The exposed film 20 is then etched by a stream of phosphoric acid directed thereon while the wafer and film assembly is rotated to remove gas bubbles formed during etching, to produce a semiconductor device having contacts 25, 26, 27, of which the last two contact the p-type regions. Three toothed spinners 20, Fig. 1, are provided. Each spinner supports an article to be etched and is rotated at 2;000 r.p.m. by a motor 52 through a gear 43, from which it can be disconnected by a cam 41. Etchant 45 is heated in a reservoir 49 by a heater 47 and pumped into a reservoir 46, whence it passes through a tube 54 into the spinner and on to the article, excess etchant collecting in a housing 43<SP>1</SP> from which it returns to the reservoir 45. |
