Reliability of High Temperature Laminates

Printed circuit boards have been reported to have limited lifetime at 200 to 250°C. Characterization of high temperature laminates for application at 200 to 250°C was conducted to better quantify their lifetime using accelerated testing of key functional parameters. Eight high temperature laminates consisting of 3 material types was evaluated. Life testing was applied for via cyclic life, weight loss, peel strength, and surface insulation resistance. Via lifetime was characterization using Interconnect Stress Test (IST) coupons. Weight loss was measured at intervals during the life of the tests. Peel strength was tested using IPC IPC-TM-650 method 2.4.8c. Weight loss was characterized using isothermal aging. Comparison of lifetime is made between the laminate samples. The non-polyimide laminates exhibited the longer life times than polyimide laminates in most tests except peel strength. Peel strength is the life limiting parameter for the laminates. Parylene HT was found to improve stability in peel strength and weight loss of one PTFE laminate tested.