Development of Laser-Induced Deep Etching Process for Through Glass Via

2.5D glass interposer technology based on through glass via (TGV) becomes a hot research topic on account of good electrical property and CTE (coefficient of thermal expansion) mismatch [1]. In this paper, the Laser-Induced Deep Etching (LIDE) technology is used to manufacture TGVs on glass substrate. The LIDE process can be mainly divided into two steps: Initially, picosecond laser is used to modified the glass substrate. Then, using 10% HF etch the modified glass substrate. On account of denaturation of the laser irradiation area, the area where is exposed to the laser will be etched more quickly than unexposed area in the process of wet etching. In consideration of the properties of various glass, SCHOTT AF 32® eco glass and CORNING HPFS 7980 fused silica glass is selected as the substrate of this study. The result show that the LIDE process is a promising high-speed TGVs manufacturing process which can fabricate TGV of high verticality (the taper angle is approximately 9° on AF 32® eco glass and 1° on CORNING HPFS 7980 fused silica glass) at a high speed (289 TGV/s). Ultimately, the stability of the break strength of the LIDE processed glass substrates is verified by the results of ANSYS simulation and three-point bending test.