레이저 유도 플라즈마 분광분석법을 이용한 연성회로기판 절단 공정에서의 탄화 특성 계측

Monitoring of carbon contamination in the cutting process of FPCB using LIBS technique

In the present study, the carbon contamination generating from the laser based cutting process of flexible printed circuit board (FPCB) is characterized by molecular spectrum emission of carbon using the technique of laser induced breakdown spectroscopy (LIBS). Using KrF excimer laser the spectrum emission of polyimide film ranging from 250 nm to 700 nm is analysed and from the result, the dominant spectrum emission of carbon contamination is identified by the C₂swan band. The total emission area of C₂swan band ranging from 500 nm to 517 nm is compared according to the laser repetition rate. Increasing the repetition rate, the integrated emission area has a tendency to decrease exponentially. When the energy per pulse of the laser decreases as 74% in comparisin between 20 Hz and 150 Hz operation condition of repetition rate, the integrated emission area decreases rapidly as 15 %. The result shows that in the cutting process of FPCB using UV laser, the reduction of pulse energy has a strong influence on the generation of carbon contamination.