| 摘要 |
1481015 Semi-conductor devices INTERNATIONAL BUSINESS MACHINES CORP 25 June 1974 [25 June 1973] 25989/74 Heading H1K [Also in Division B3] In bonding a semi-conductor device to a conductor on a substrate by solder, the device is placed on the substrate with a solder pad on the device in contact with the conductor and the solder pad is reflowed, a ternary intermetallic including palladium being dispersed within the solder and the palladium being derived from a layer thereof provided on the device. A semi-conductor chip 70 comprising integrated circuits has deposited thereon a chromium layer 72, a copper-chromium layer 74, a copper layer 76, a palladium layer 78, a lead region 80 and a tin layer 82. The chip is heated to homogenize the structure and then with the solder resolidified is inverted on a printed circuit carrying ceramic substrate 90 carrying a chromium layer 92, a copper layer 94 and a chromium layer 96. At the interface between the chip 70 and the lead-tin solder 98 there exists a thin chromium layer 100, a binary copper-tin layer 102 and a ternary copper-tin-palladium within the solder. Different concentrations 104, 106 of the intermetallic exist in the solder. A similar prior art system is described in which instead of the palladium layer a gold layer is used and a binary copper-tin zone is produced. Reference is made to Specifications 1,159,979 and 1,143,815. |
