| 摘要 |
<p>1,211,657. Semi-conductor devices. R.C.A. CORPORATION. 10 March, 1969 [28 March, 1968], No. 12470/69. Heading H1K. A metal layer on a semi-conductor device is patterned by covering it with an adherent resistant insulating layer, by photo-resist masking and etching the insulating layer, and by using the insulating layer as a mask while etching the metal layer. This method avoids the excessive undercutting often found when a photo-resist mask (which adheres poorly) is used directly on a metal layer. The planar diode shown has a silicon body consisting of a substrate 3 and epitaxially grown layer 2 with diffused P and N<SP>+</SP> regions 1, 16. The P region is formed by diffusion from a deposited borosilicate glass layer. The initially overall deposit of aluminium 7 (or instead gold or tungsten) is separated into the two electrodes for the diode by etching it through the apertured pyrolytically deposited silicon dioxide layer 8 (direct oxidation of silane is used), itself patterned by photo-resist masking and etching. A mixture of HF, NH 4 F, and CH 3 COOH is used for etching the oxide a mixture of HNO 3 and H 3 PO 4 is used for etching the aluminium. The entire surface is then coated with silicon dioxide 12 and both oxide layers etched to expose areas of the metal to which leads may be ultrasonically bonded. Since the silicon dioxide is a stronger mask than the photo-resist, it is possible to simultaneously etch metal layers (on different wafers) which differ in thickness without overetching the thinnest ones.</p> |
