IPC TM-650 2.6.26A

Abstract

These methods determine the physical endurance of representative coupons of printed boards to a series of high temperature excursions from ambient. The temperature excursions cause thermo-mechanical fatigue of the electrical interconnect structures. <br>The test coupon is resistance heated by passing DC current through the coupon to bring the temperature of the copper to a designated temperature. Switching the current on and off creates thermal cycles between room temperature and the designated temperature within the sample. The laminate and surrounding materials are heated to different extents depending on the thermal conductivity of the materials. The thermal cycling can accelerate latent interconnect anomalies to failure. <br>The number of cycles achieved permits a quantitative assessment of the performance.