Development of CO2 laser drilling system controlled by concurrent in-line inspection monitoring for printed wiring boards

Abstract

The performance of a CO2 laser drilling system was improved by real-time process control with concurrent in-line inspection monitoring for printed wiring boards. The principle of the concurrent in-line inspection monitoring method was based on the relationship between the exposed bottom area of the inner layer copper foil in the via hole and the intensity of the reflected laser light. The end of the drilling process was detectable by the saturation of the reflected laser light intensity generated at the copper foil surface of the blind via hole.In this paper, the development of the CO2 laser drilling system for printed wiring boards, which is controlled by concurrent in-line inspection monitoring, is described. We carried out the drilling process for glass-cored epoxy substrate and observed that the productivity of the drilling process was increased by about 30 % due to control by concurrent in-line inspection monitoring.The performance of a CO2 laser drilling system was improved by real-time process control with concurrent in-line inspection monitoring for printed wiring boards. The principle of the concurrent in-line inspection monitoring method was based on the relationship between the exposed bottom area of the inner layer copper foil in the via hole and the intensity of the reflected laser light. The end of the drilling process was detectable by the saturation of the reflected laser light intensity generated at the copper foil surface of the blind via hole.In this paper, the development of the CO2 laser drilling system for printed wiring boards, which is controlled by concurrent in-line inspection monitoring, is described. We carried out the drilling process for glass-cored epoxy substrate and observed that the productivity of the drilling process was increased by about 30 % due to control by concurrent in-line inspection monitoring.