| 摘要 |
1,080,618. Mounting semi-conductor devices on printed circuits; printed circuits. STANDARD TELEPHONES & CABLES Ltd. July 22, 1966, No. 33056/66. Headings H1K and H1R. An insulating substrate of glass or ceramic may form the base of a printed circuit and bears conductive lands from which extend conductive fingers integral therewith but spaced from the substrate and which make contact with electrode areas on an integrated circuit mounted on and/ or under the fingers. Several integrated circuits and other components may be mounted on the substrate. To make a particular structure, the substrate is first coated in selected areas with aluminium, and gold is then coated over the entire substrate and photoresist masked and etched to the desired pattern of lands and fingers (or it may be deposited in the desired pattern). Those portions of the fingers which are to be spaced from the substrate are formed over the aluminium deposits. The metal coatings may be applied by vapour deposition, chemical plating, spraying, painting, or gluing. The aluminium is then selectively etched away using a solution of sodium hydroxide and potassium bromide. The fingers may be pulled further away from the substrate by suction nozzles so that an integrated circuit may be slid beneath them and, if desired, bonded to the substrate. The fingers are then joined to the electrodes by thermocompression bonding, for example. As a variant the integrated circuit may be inverted and placed on the fingers to which the electrodes are bonded by heating the structure in an oven or, if the substrate is transparent, by the use of laser welding. A portion of the integrated circuit may be bonded directly to the substrate to take the weight off the fingers. If the integrated circuit is to be mounted only on the fingers the aluminium need not be etched away until bonding has taken place. In a modification some fingers may be pulled away from the others so that a circuit may be slid between the two sets of fingers which are then bonded to electrodes on the two faces of the circuit. |
