| abstract |
1,235,811. Electrolytic etching, plating. TEEG RESEARCH INC. May 21, 1968 [June 26, 1967], No.43778/69. Divided out of 1, 234, 302. Heading C7B. [Also in Division G2] An exposed and developed photo-resist (see Division G2) consisting of a metal (e.g. silver) layer 420 covered in certain areas by dielectric (e.g. arsenic trisulphide) layer 422 is electrolytically etched by placing the resist in enclosure 460 and making the metal layer 420 the anode via electrical contact 466. Contact 471 in metal plate 470 is the cathode and an electrolytic solution (e.g. sodium chloride) is circulated at high velocity and at a pressure between 10 and 50 p.s.i. between the cathode and anode. A direct current of 10 to 20 volts is used and metal layer 420 is partly or completely etched. Alternatively, metal layer 420 may be electro-plated in an electro-plating bath to produce a metallic coating which may be thicker or thinner than layer 422. To prevent plating of layer 422, it may be coated with an oil before electro-plating. Layer 422 may be arsenic tri- or penta-sulphide, arsenic or bismuth. |