| 摘要 |
1,104,090. Printed circuit assemblies. INTERNATIONAL BUSINESS MACHINES CORPORATION. 7 Dec., 1966 [14 Jan., 1966], No. 54792/66. Heading H1R. [Also in Divisions G1 and H2] In a device for making temporary electrical connection to an integrated circuit to be tested (see Divisions G1 and H2) in which contacts carried on a transparent plastics diaphragm are blown by air pressure applied to the diaphragm, into contact with corresponding terminals on the circuit to be tested, the terminals and their connecting conductors are printed on the sheet. To form the printed circuit, the sheet is first clad on both sides with electrolytically deposited copper, the coating on one side being only used to stiffen the sheet while the printed circuit is formed. The coating on the other side is then coated with a photo-resist applied while the sheet is rotating on a spinner, and after baking the resist is exposed over all areas other than those forming the required pattern of conductors. After developing the resist in the areas of the pattern can be removed and this part of the copper plated with gold after which the remaining areas of copper are stripped of resist and removed by etching, or if a positive resist is used, the exposed areas can be removed and these areas of copper etched away after which the resist on the pattern is stripped and the pattern is plated with gold. Following either of the above steps a negative resist is applied over the face carrying the pattern, and all areas other than a central probing region are exposed and developed. The terminals and conductors in the probing area are then brush-plated with gold and the terminals are further plated with rhodium to give a hard rough surface which can break through any oxide &c. on the terminals of the circuit to be tested on impact in response to the applied air pressure. |
