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°C, more than 10¹² Ω/cm) and to heat (4×10¹² Ω/cm at 121°C), while still maintaining the same rubberlike elasticity as typical urethane resins. It also has much less ionic impurity (Na⁺=less than 5 p.p.m., Cl^-=less than 10 p.p.m.), as well as a good migration feature (PCT/121°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°C, 100% RH, 20-mm Hg), 200 cycles in heat-cycle tests (-55°C/30 min to 125°C/30 min), hot storage at 125°C/500 h, and cold storage at -55°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