| abstract |
PROBLEM TO BE SOLVED: To provide a laser processing apparatus, a multilayer printed wiring board manufacturing apparatus and a manufacturing method capable of forming a via hole having a small diameter at low cost. SOLUTION: The laser beam from a CO 2 laser oscillator 60 is shortened in wavelength by a tellurium crystal 94 to suppress the diffraction of the laser beam and to reduce the limit value of the laser beam when the laser beam is focused. Thereby, the spot diameter of the laser beam is reduced, and a hole for a via hole is formed in the interlayer insulating resin on the substrate 10. For this reason, even when the output of the laser beam is increased to form a deep hole, the hole diameter is not increased, so that a small-diameter via hole can be formed. |