Multilayer printed wiring board and test body for printed wiring board

Abstract

There are provided a multilayer printed circuit board and a testing piece for the printed circuit board, including a substrate having an inner-layer conductor circuit and one or more outer-layer conductor circuits formed on the substrate with an insulating layer laid between the substrate and outer-layer conductor circuit, wherein a strain gauge having a resistive element held tight between resin films formed from polyimide or thermoplastic resin is buried in the substrate, and electrodes electrically connected to the resistive element are exposed to outside from the resin film and are electrically connected at exposed portions thereof to a viahole. Even if a crack is caused by an impact test to take place in the insulative resin layer, the resin film layers prevent the crack from spreading and thus the resistive element forming the strain gauge will not be ruptured. Also, not only the information on strain in the surface layer of the circuit board but also information on strain in a desired position can be measured accurately, so that an actual stress given to the circuit board can accurately be determined.