| 摘要 |
PROBLEM TO BE SOLVED: To prevent a circuit board from being contaminated by depositing a sacrificial layer on the surface of the circuit board, forming a hole on the circuit board by laser aberration, sucking a foreign object being generated at that time by the sacrificial layer, and eliminating the sacrifice layer along with the foreign object. SOLUTION: In a PCB, a copper layer is formed on the both surfaces of a substrate 10 that is made of a resin system. Then, a solder layer with a specific thickness is deposited on the top surface of the copper layer. The circuit board is then mounted to a scanning table 15 and is exposed to beams 16 from a pulse ultraviolet-ray excimer laser 17. The table 15 is indexed in two directions by a motor, so that the circuit board can obtained a specific pattern in relation to the beams. The laser beams pass through a hole, are absorbed by the exposed part of the substrate 10, and form an aberration and a hole through the substrate. In this case, the thin pieces of aberration are emitted from the hole and are deposited on a solder layer around the through-hole. Then, the solder layer that contains the foreign object by adsorption is chemically eliminated by dipping into a solder elimination solution. |
