Thermal Reliability Test
A quality control procedure where a sample of a circuit board is floated on the surface of molten solder determines the material’s resistance to delamination and blistering. Solder float simulates the extreme thermal shock that a board experiences during the assembly process. It is a standard method for verifying the integrity of the bond between the copper and the dielectric.
Test Procedure
The specimen is typically placed on a solder bath at 288 degrees Celsius for a fixed period of ten seconds. After the solder float, the sample is cross-sectioned and examined under a microscope for any signs of layer separation or resin recession. This test catches latent defects that might not be visible after a standard reflow cycle.
International standards define the maximum allowable degradation of the material after the exposure. Passing the test provides confidence that the board can survive the heat of modern lead-free assembly without failing. It remains a fundamental requirement for the qualification of new laminate materials and fabrication processes.
Acceptance Criteria
Microscopic analysis confirms the absence of internal cracks or separation after the thermal exposure. If a board fails the solder float, the entire production lot is usually quarantined for further investigation. This test is a critical gate for ensuring the long-term reliability of electronic hardware.
