High-Throughput Fabrication of Glass Micro-Vias Through a Direct Laser Ablation Process Utilizing a DOE and an Optimized KrF Excimer Laser

Artificial intelligence (AI) and high-performance computing (HPC) are demanding unprecedent computing power and the advanced packaging has been seeking new materials to continue the scaling in performance, power, area, and cost (PPAC). The silicon interposer has been challenged by its scalability by 300mm wafer and reticle size. The organic-core substrate is suffering to increase its body size with high-density wiring by a lack of stiffness and surface roughness. Glass has been investigated as a promising substrate core material because of its tunable properties (e.g., coefficient of temperature expansion and modulus, etc.) and panel scalable manufacturing technologies. Additionally, their high rigidity and smoothness enable high-density wiring. We present a micro-via fabrication technology using KrF excimer laser direct ablation drilling. This method offers several advantages, including: 1) the ability to process in both organic and inorganic materials, 2) no need or reduction of etching, 3) the capability to fabricate high aspect ratio Through-Glass-Via (TGV) (diameter: <20microns, aspect ratio: >50) in thick glass exceeding 1 mm, 4) high productivity through specially designed optics, and 5) easy scalability to panel size. In this study, we demonstrated the ability to achieve high productivity processing of over 1000 high aspect ratio TGVs per second using a single excimer laser light source and a DOE (Diffractive Optical Element). By exchanging the DOE, it is possible to change the number of holes processed simultaneously. Additionally, metallization tests are currently being conducted.