Unique polybutadiene resin-characteristics after hardening and application to IC

Tests results on a urethane-modified polybutadiene formulated for use on electronic parts are reported. This polybutadiene resin is shown to have excellent insulating resistance to humidity (pressure cooker test, or PCT/121 degrees C, more than 10/sup 12/ Omega /cm) and to heat (4*10/sup 12/ Omega /cm at 121 degrees C), while still maintaining the same rubberlike elasticity as typical urethane resins. It also has much less ionic impurity (Na/sup +/=less than 5 p.p.m., Cl/sup -/=less than 10 p.p.m.), as well as a good migration feature (PCT/121 degrees C, 100% RH, 24 h, 90 VDC). The resin was applied to integrated circuits as an encapsulation material. The results were excellent: 100 h for PCT (121 degrees C, 100% RH, 20-mm Hg), 200 cycles in heat-cycle tests (-55 degrees C/30 min to 125 degrees C/30 min), hot storage at 125 degrees C/500 h, and cold storage at -55 degrees C/550 h. This resin is expected to be used as an encapsulation material for VLSI or automotive electronics, with the latter fully utilizing the resin's elasticity.<
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