| 摘要 |
1,175,272. Semi -conductor devices. WESTERN ELECTRIC CO. Inc. 26 Jan., 1967 [10 March, 1966], No.3932/67. Heading H1K. [Also in Division C7] In fabricating a semi-conductor device, an Al layer on a semi-conductor body (e.g. of Si) is electrolytically etched in an aqueous solution of tetraalkylammonium hydroxide R 4 N<SP>+</SP>(OH)<SP>-</SP> using a metal cathode so as to remove A1 from the layer. R may be methyl, ethyl, propyl or butyl. The four alkyl radicals in the compound may not all be the same but may be selected from the above radicals. As shown, a Si transistor element 10 of PNP configuration has thereon a silicon oxide mask 16, a Ti layer 17, an A1 layer 18 and a photoresist mask 19. Unmasked parts of the Al layer are electrolytically etched in a 2% aqueous solution of tetramethylammonium hydroxide at 25‹ C. The element may be suspended by metal tweezers which comprise one electrode connection. The cathode may be a Mo rod positioned one inch from the A1 surface. The electrolytic etching may be at 10,000 Angstroms per minute using 200 milliamps. Unmasked parts of the Ti layer are removed by chemical etching in a solution of dilute H 2 SO 4 and HF. Subsequently the photoresist mask is removed. |
