Fiber Laser Cutting of Alumina Substrates for Electronic Applications Comparison of the Experimentally Determined and Simulated Influence on the Mechanical Strength

Abstract

This study compares experimentally determined and simulated mechanical strength of different geometries laser cut into alumina ceramic substrates. A digital power modulated 500 W single mode fiber laser is used to cut differently shaped inner contours into rectangular ceramic substrates. The flexural strength of these samples is measured by a 3-point-bending test. In addition, employing a finite element simulation the principal stress of these geometries during a 3-point-bending is simulated with a linear elastic model. The reciprocal of the simulated stress is compared with the measured strength revealing an excellent agreement. We, therefore, can conclude that the strength reduction by cutting inner contours can be exclusively explained by the geometry of the rectangular, which in turn implies that the fiber laser cutting process itself causes no relevant additional structural damage. These results highlight the superior quality of digital power modulated fiber laser cutting of ceramics. Moreover, we demonstrate by a further comparison between experimental and simulated results that an increased strength is feasible by displacing fragile parts of inner contours to areas with less mechanical load.

Picosecond laser microvia drilling of ABF material using MHz burst mode

“…The trend towards miniaturized high-performance electronic components driven by increasing demands on their functionality requires a high-density electronic packaging and interconnection technology. Hence, laser drilling has been intensively studied for various materials used in interconnect devices, such as, e.g., ceramics or different printed circuit board (PCB) materials [1][2][3][4][5][6]. In particular, ultrashort pulsed (USP) laser percussion drilling has been established for the fabrication of blind vias, so-called microvias, to inner conductive layers in multi-composite PCB material [5][6][7][8] with small diameters of <10 μm [9,10].…”