What is a PCB Test Coupon?

During the PCB Manufacturing process, it is important to evaluate the quality of the boards being fabricated. A good way to do this is to fabricate a few extra boards called PCB Test Coupons which can be tested to evaluate the performance of the boards. PCB Test Coupons are designed to have the same spec (trace width, copper weight, via structure, etc.) as the original PCB board and are tested to identify manufacturing defects, material defects or other related defects. 

During the PCB Fabrication process multiple PCBs are fabricated on a large board called a panel. The PCB Test Coupon is usually not a part of the core PCB panel, is built in section surrounding the PCBs. They are designed to represent actual board conditions for plating, etching and lamination. It's common to fabricate one coupon at each end of a board panel to verify performance across the entire panel. Any defect identified in the PCB Test Coupon would mean that other boards on the same panel would have the same issues.

Advantages of using PCB Test Coupon:

• There is always a coupon which can be analyzed without the need to cut samples from any of the PCBs in a batch. 
• Coupons are the best way to measure and characterize the real-life PCB conditions.
• They can be standardized using fixtures to speed up the testing process.
• Apt for destructive testing, say demanding testing without damaging the desired PCB.
• Monitoring of the production and assembly processes becomes easier, hence increases the production yields.