Embedded features for registration measurement in electronics manufacturing

摘要

Etch features are included on a printed circuit (PC) board to be used in monitoring and controlling assembly processes such as soldering. A vernier pattern of etch blocks receives corresponding solder blocks during solder paste screening; misalignment of the solder stencil to the PC board is indicated by an easily-seen interference pattern of spaces created by the superimposed etch and solder blocks. The degree of misalignment can be determined by measuring the distance between the center of the interference pattern and a reference etch block. Also, a scale pattern of etch receives a bar of solder paste; misalignment in the direction orthogonal to the long axis of the scale is indicated by the location of the intersection of the long axis and the solder bar.