Test coupons for determining the registration of subsurface layers in a multilayer printed circuit board

摘要

The present disclosure describes test coupons having predetermined respective test patterns, formed in a multilayer printed circuit board simultaneously with the fabrication of the latter. The test coupons are probed with conventional electrical instruments to provide information as to the occurrence of a misregistration of any given subsurface printed plane or trace, whether or not the misregistration exceeds a specified limit, and if desired, a measure of the degree of misregistration. The foregoing are readily accomplished in a time and cost efficient manner without the need for cross-sectioning portions of the board and the visual observation of the subsurface printed layers.