Leiterplatte und Verfahren zu deren Herstellung

摘要

A circuit board includes an electrical insulator layer formed of a reinforcer sheet (101) with density distribution in its in-plane direction, an electrical conductor filled in a plurality of inner via holes provided in the electrical insulator layer in its thickness direction, and a wiring layer connected to the electrical conductor. The inner via holes (104) provided in a high-density portion of the reinforcer sheet (101) are formed to have a smaller cross-section than the inner via holes (103) provided in a low-density portion of the reinforcer sheet. In this manner, it is possible to provide a circuit board that can achieve a high-density wiring and an inner via connection resistance with less variation, when a base material including a reinforcer sheet with density distribution in its in-plane direction such as a glass cloth formed of warps (102b) and wefts (102a) is used for an insulator layer.