Definition

Test coupons are dedicated structures that replicate production board features for quality verification without destructive testing of product boards. Impedance coupons contain transmission line structures (same layer, trace width, and stackup as the product) with probe launch pads for TDR measurement - typically 100-150 mm trace length for clean readings. Microsection coupons are cross-sectioned to verify plating thickness, hole quality, and registration. Coupons are usually placed in panel margins (same process conditions as product, discarded at depaneling), as breakaway tabs (stays with board until customer removes), or on separate test panels (retained by fabricator as batch records). Standard practice: fabricator measures, logs results, and provides a test report; physical coupons delivered only on request for incoming QC or audit purposes.