| 摘要 |
<p>PURPOSE: A method is provided to accurately and easily detect whether a hole passed through an insulating layer. CONSTITUTION: At making of a hole(13) through the insulating layer(10) of a printed wiring board(1) for electrical continuity of a conductor(11) formed on the insulating layer(10) with a conductor(12) formed under the layer(10) and exposing the lower conductor(12) in the bottom of the hole(13), a printed wiring board provided with a treated layer(14), which radiates an electromagnetic wave having a different wavelength from that of a laser beam for machining at performing laser beam machining between the lower conductor(12) and the insulating layer(10) is used as the printed wiring board(1) and at the time as performing of the laser beam machining for making the hole(13) through the insulating layer(10), the remaining state of the layer(10) is discriminated by measuring the change of a signal generated from the treated layer(14) of the board(1) Since the reflected light of the laser beam is not utilized, and electromagnetic waves, radiated from the treated layer(14) provided between the conductor(12) and insulating layer(10) when the laser beam machining is performed, are utilized, whether or not the hole(13) passed through the insulating layer(10) can be detected precisely.</p> |
