METHOD FOR MEASURING AMOUNT OF HEAT IN METAL FOIL, METHOD FOR ADJUSTING SURFACE CHARACTERISTICS, LASER DRILLING METHOD, AND APPARATUS FOR MEASURING AMOUNT OF HEAT

摘要

A method for measuring amount of heat in metal foils wherein a small amount of laser light is directed to a metal foil and the amount of heat absorbed by the metal foil is measured by a sensor disposed on the back surface of the metal foil is disclosed. It is also disclosed an apparatus for measuring amount of heat in metal foils comprising a laser light introducing pipe having a light-reflective inner surface; a unit for placing a metal foil, which is subjected to measurement of amount of heat, on the bottom portion of the laser light introducing pipe; and a sensor for measuring amount of heat, which is in close contact with the back surface of the metal foil. A method for forming a small interlayer connection hole (through hole) in a printed circuit board wherein the amount of heat in a metal foil is measured for efficiently forming the interlayer connection hole and drilling with a laser can be conducted easily is disclosed. The resulting small interlayer connection hole (through hole) is excellent in quality and stable. An apparatus used therefor is also disclosed.