High Tg Circuit Board

A PCB built on high-Tg FR-4 with a glass-transition temperature of 170°C or higher, used in applications that see prolonged operation at elevated temperatures or aggressive thermal cycling. Above the Tg of standard FR-4 (about 130°C) the resin softens, copper-to-resin adhesion drops, and Z-axis expansion accelerates, which can crack plated through-holes and microvias. High-Tg laminate pushes that softening point well above typical operating temperature, so the Z-axis CTE stays low through assembly reflow and field life. Typical uses are automotive under-hood electronics, EV power electronics, industrial inverters, lead-free assembly with multiple reflow passes, server power supply boards, and any high-current or high-density board where IPC-6012 Class 3 reliability has to be demonstrated.