| 摘要 |
1293140 Resistors; capacitors WESTERN ELECTRIC CO Inc 18 Nov 1969 [19 Nov 1968 11 Dec 1968] 56377/69 Headings H1M and HIS] [Also in Division C7] A thin-film resistor has a substrate on which is deposited a film of a ceramic material and a metal or metallic compound, its resistance then being increased to a desired value by electrochemical anodization. The resistance film may be deposited by co-sputtering the metal, e.g. tantalum, and the ceramic metal, e.g. an oxide of silicon or aluminium, using the apparatus of Fig. 2, not shown (see Division C7). An alternative method, Figi 1, heats the substrate and its coating of the ceramic prior to the impregnation by the metal or metallic compound. Contact pads are deposited on the resistor once it has been patterned or cut into strips, which may be by a conventional photo-etching technique or by originally sputtering through a suitable refractory metal mask. Successive layers of chromium or michrome, copper, platinum or other noble metal are deposited by evaporation through openings in a mask, to form the contact pads. Conductive leads are attached by ultrasonic bonding. The resistor is then electrochemically anodized to increase its resistance, by transforming some of the tantalum into tantalum pentoxide, Fig. 4 (not shown) (see Division C7). The composition of the anodized mixture of Ta and Si oxide is suitable for use as a capacitor dielectric. The resistor is finally thermally aged to increase its stability. Aluminium oxide may replace the silicon oxide as the ceramic material and tantalum nitride used as the metallic compound. |
