Real time analysis for Laser drilling vias of 5G Material with Multiphoton microscopy

The ultrafast laser for material processing concentrates the pulse energy into the scale of picosecond or femtosecond temporal duration. The high peak power would induce nonlinear multiphoton fluorescence, material modification and photoablation with higher pulse energy [1]-[3]. With the increase of processing resolution and complexity, we would propose the noninvasive inspection method by integrating with multiphoton excited fluorescence microscopy (MPEFM) to directly monitor the processed structure in specimen for verification and analysis [1]. In this paper, we would show the setup of FPGA-based MPEFM and adopt the single photon counting (SPC) technique for high signal-to-noise (SNR) images. The image spatial resolution is submicron level. To the need of the high bandwidth electrical components and applications in industry, companies are developing different kinds of composite materials and insulators together with the technology of different kinds of laser processing methods and protocols including direct writing, drilling, and modification with etching-assistance. Glass and polyimide (PI) are important materials for the insulation layer in PCB (printed circuit board) design and the narrow electrical routing structures are especially required to be confirmed after processing [4], [5]. We have shown the MPEFM can detect the axial-resolved images of the laser modified surface on the silicon glass and the laser-cut structure on the PI film without damaging the specimen. The mechanism shows the potential for the rapid 3D inspection of the laser processed specimen.