| abstract |
A method and apparatus for selective material removal and via drilling for semiconductor applications using an ultrafast laser pulse directly from an ultrafast pulse laser oscillator without amplification are disclosed. The method and apparatus includes techniques to avoid/reduce the cumulative heating effect and to avoid machine quality degrading in multi shot ablation. Also the disclosed method and apparatus provide a technique to change the polarization state of the laser beam to reduce the focused spot size, and to improve the machining efficiency and quality. The disclosed method and apparatus provide a cost effective and stable system for high volume manufacturing and inspection applications. The disclosed method and apparatus have particular applications in, but not limited to, drilling vias for interconnect formation, selective material removal for application specific integrated circuits, selective material removal for flash memory applications, exposing layers for further semiconductor processing such as wire bonding etc. The ultrafast laser oscillator can be a called a femtosecond laser oscillator or a picosecond laser oscillator depending on the pulse width of the laser beam generated. |