Reliability of the advanced COPNA-resin laminate which exhibited high glass transition temperature (Tg) at 255/spl deg/C, low coefficient of thermal expansion (CTE) at 5-7 ppm (xy-axis) and at 29 ppm (x-axis) was evaluated by temperature-humidity-bias (THB) test, pressure-cooker (PC) test, heat-shock test, heat-cycle test, and conductive anodic filaments (CAF) test. The laminate exhibited higher reliability than the FR-4 graded epoxy-resin laminate in every test, and exhibited higher reliability than the bismaleimide-triazine resin laminate in the THB test, heat-shock test, and heat-cycle test. The high reliability of the advanced COPNA-resin system is considered to be due to its high Tg and small CTE. In this paper, low CTEs of the advanced COPNA-resin laminate are also theoretically studied by using a model for uni-axially reinforced composites.