| 摘要 |
1,209,781. Printed circuits. WESTERN ELECTRIC CO. Inc. 31 Oct. 1967 [31 Oct., 1966], No. 49351/67. Heading H1R. A thin film distributed RC network comprises a substrate 11, a layer (12) (Figs. 1 to 5, not shown) of film forming metal deposited on the substrate, a layer 14 of the oxide of the film forming metal formed by anodizing the surface except for terminal 13, and a tantalum layer 17 wherein the density of the tantalum is less than 16 grams per c.c. The first metal layer is formed by vacuum evaporation or cathode sputtering, the low density tantalum layer by cathode sputtering at 800 to 2500 volts at partial pressures of 10 to 100 microns mercury. Photoengraving techniques are used to give the desired pattern to layer 17 and the resistance of the layer is increased by anodizing until the frequency response curve equals that desired. |
