| 摘要 |
PURPOSE:To form a flat shape which has less ruggedness on a worked surface by providing materials which are unified in absorptance to electromagnetic waves to constitute the materials for constituting a printed circuit board. CONSTITUTION:An oxide film 4 is formed on the surface of a copper foil layer 1, by which the absorbance of the copper foil layer 1 is improved. Epoxy is used for the base of a resin layer 2 and fine powder of silica is incorporated therein to suppress the absorbance of the resin layer 2. A material formed by incorporating Fe<3+>, etc., into glass which is a reinforcing material is used for a glass cloth layer 3 to improve the absorbance of IR. The printed circuit board constituted in such a manner can be worked to the flat sectional shape having the less ruggedness in the resulted hole when this printed circuit board is irradiated with a CO2 laser under prescribed conditions. The absorptances of the copper, resin, glass, etc., to wavelength light are uniformized to about the same level at a high level above the prescribed value in such a manner, by which the respective constituting materials are decomposed and evaporated to about the same extent and the worked section having the flat shape with the less ruggedness is obtd. |
