Alcohol Modified RTV Silicone Encapsulation for Integrated Circuit Device Packaging

Room temperature vulcanized (RTV) silicone elastomer has been proven to be one of the most effective encapsulants for mechanical, moisture, electrical, and alpha particle protection of bipolar, metal--oxide semiconductor (MOS), and hybrid integrated circuit (IC) devices. This RTV material is also one of the few commercial polymer materials that meets Bell System encapsulant specifications. The chemistry of the silicone elastomer and its intrinsic properties as an IC device encapsulant will be addressed. The advantages of using the alcohol modified silicone encapsulant for mechanical protection, enhancement of electrical performance in bias humidity temperature (BHT) testing, and protection against alpha particle-induced "soft errors" in memory devices (e.g., the 64K DRAM) will be discussed. The physical, mechanical, and cure properties of the alcohol modified silicone dispersions have been investigated and the performance of these encapsulants in bias humidity temperature electrical testing and production coating experiments has also been characterized. When the alcohol diluent is added according to the prescribed method in concentrations at or below the optimum level for coating performance, no degradation of specified properties is observed. The optimum formulation for the alcohol modified Dow Corning encapsulant has been identifid as six weight percent dry isopropyl alcohol added to the DC3-6550 RTV silicone as received.