| abstract |
There is provided a laser processing apparatus, anmultilayer printed wiring board manufacturing apparatus, andna manufacturing method to form via holes of ultra-fine diameter.nThe laser beam from the CO 2 laser oscillator (60) is convertednto the shortened wavelength beam by a tellurium crystal (94)nto control diffraction of the laser beam. Simultaneously, whennthe laser beam is condensed, a limit value of the condensationnlimit is reduced. Thereby, the spot diameter of laser beam isnreduced and a hole for via hole is bored on the interlayerninsulation resin on a substrate (10). Therefore, even when thenlaser beam output is raised to form a deeper hole, the holendiameter is not widened and thereby a hole for a small diameternvia hole can be formed. |