| 摘要 |
1364898 Coating with tungsten or molybdenum RCA CORPORATION 9 Dec 1971 [14 Dec 1970] 57351/71 Heading C7F [Also in Division H1] A silicon dioxide layer is coated with W or Mo by deposition from WF 6 or MoF 6 . A silicon chip 2, having a transistor 8, 10 and resistor 6 fabricated therein, has a coating of SiO 2 12, etched to form openings 14, 16, 18, 20. The chip 2 is heated in a chamber to 500-800‹C, preferably 700‹C after which an inert gas, e.g. N 2 , reducing gas, e.g. H 2 , and gaseous WF 6 (or MoF 6 ) are fed in, the ratio of N 2 :H 2 being between 20:1 and 40:1. A deposit of W 54, is formed in the openings 14, 16, 18, 20 by Si replacement, whilst the gaseous WF 6 etches the SiO 2 surface, and a thin layer of W 56, is formed by reduction of the WF 6 . After this partial deposition, the WF 6 flow is stopped, the chamber purged with N 2 , and then WF 6 and H 2 only are fed in resulting in extra deposition of W on the previous layer 56. Finally, the chamber is again purged with N 2 . Unwanted W (or Mo) can be removed by any suitable etching technique. |
