| 摘要 |
999,679. Sem-conductor devices. BROWN, BOVERI & CO. Ltd. March 28, 1963 [March 30, 1962], No. 12319/63. Heading H1K. The carrier plate 2 (e.g. of molybdenum) and top electrode 3 (which may be of gold) of a semi-conductor element 1, Fig. 1, are connected with respective terminal elements 4, 5, by layers 10, 11 of a solder which is fluid at the operating temperature of the device. This prevents breakage of the soldered connection which thermal stresses produce when hard solders are employed, allows the use of a thinner carrier plate with improved heat transfer to the terminal element 4 (also acting as a heat sink) and prevents damage to the semi-conductor element by the high temperatures associated with hard soldering. When fluid, the solder layer 11 is retained by capillary forces and by surface tension but when the device is to be subjected to high accelerations the outer edge of the solder is preferably sealed by a layer 12 of silicon lacquer or, as shown in Fig. 2, by a ring 13 of silicon rubber or of lead retained by a groove in the terminal element 5. The carrier plate 2 may be dispensed with and the element 1 soldered directly by the fluid solder to terminal element 4. To prevent the solder from solidifying at high temperatures due to the formation of higher melting temperature alloys or compounds with the material of the adjacent surfaces the latter (electrode 3 and terminal element 4 when the carrier plate 2 is not employed) are preferably covered by layers of molydbdenum, or tungsten with which the solder forms no alloy or compound. The solder may comprise those metals and alloys which are fluid in the range of 30‹ to 130‹ C. Gallium (melting point 29À8‹ C.) is mentioned. Mercury is also stated to be suitable. |
