Temperature cycling of surface mounted thick film 'zero-ohm' jumpers

Thermal cycling tests for surface mounted components are usually taken around a mean temperature of approximately 35°C (e.g., -55°C to +125°C; -40°C to +110°C). To test the effect of different maximum temperatures thermal cycling tests using a lower temperature of -55°C have been conducted with alumina/thick film 'zero-ohm' jumper chips with nickel barriers. These are connected in series chains and wave soldered on to FR-4 test coupons (128 chips/coupon). The test regimes used were -55°C to +5°C; +65°C; +95°C, +110°C and +125°C. Resistance changes before and after cycling were observed at room temperature. After 100 cycles changes of approximately +200 mΩ were observed against a total resistance of 5.5 Ω. However, more detailed examination showed that a top temperature of +95°C gives optimum results with a total change over 100 cycles of +4.9%.