| 摘要 |
<p>1,226,814. 814. Electro-plating gold contacts on semi-conductors. WESTERN ELECTRIC CO. Inc. April 18, 1968 [Aug. 4, 1967], No.18294/68. Heading C7B. [Also in Division H1] In making connection to a metallic layer on a semi-conductor body by electro-plating layers of titanium and titanium dioxide are formed successively on the metallic layer and a photo-resist mask then applied to the oxide to delineate the areas for deposition. In the embodiment apertures are first formed in the oxide layer over the emitter and base regions of a planar diffused transistor. After depositing platinum in the apertures and heating to form platinum silicide, titanium 17 Fig. 3 is deposited overall and keys to the oxide 16. A further layer of platinum 18 is applied followed by an evaporated layer 19 of titanium 400-1000Š thick, which is oxidized by exposure to the atmosphere. A photo-resist mask defining the contact areas is then applied and the unmasked titanium oxide and titanium removed by etching in a hydrofluoricsulphuric acid mix. Then, after removing the photo-resist if desired, gold is electro-plated on the exposed platinum. Alternatively the exposed platinum is removed by chemical etching or cathode back-sputtering and the gold plated on the underlying titanium. Finally the photo-resist material is removed and the layers not masked by the gold contacts treated in a mixture of hydrofluoric and sulphuric acids to remove the titanium and in a mixture of hydrochloric and nitric acids to remove the platinum.</p> |
