To form a through-hole with a small taper on a substrate while the damage of a film on the substrate is suppressed.
In the method according to this invention, a substrate 10 whose surface is mounted with an electron device is worked. At first, a film 12 forming a part of the electron device is formed on the surface 10a of the substrate. Next, the back face 10b of the substrate is irradiated with a laser beam 20, and the substrate is penetrated from the back face thereof so as to form a through-hole 30 extending to the film on the surface. When forming the through-hole, the laser beam is emitted while being converged on a convergent point A arranged at the inside of the substrate. The convergent point is fixed at least in the direction of the optical axis 21 of the laser beam.
Shiro Terasaki
Hiroaki Aoki
Ikeda adult