Lead-Free Low-Melting and Semiconductive Vanadate Glass Applicable to Low-Temperature Sealing

摘要

We optimized the fundamental composition and additives in a semiconducting V_2O_5-P_2O5-TeO_2 glass system to develop lead-free low-melting glass suitable for low-temperature sealing below 400°C. Glass with a composition of 55.7V_2O_5-19.8P_2O_5-23.5TeO_2 (mol%) has a low glass transformation temperature (Tg < 300°C) as well as hard crystallization, and it is desired as a low-temperature sealing material. The effects of adding BaO, SD_2O_3, MnO_2, or Fe_2O_3 to the fundamental composition of 55.7V_2O_5-19.8P_2O_5-23.5TeO_2 (mol %) on the thermal properties and water-vapor resistance were then characterized. Adding 11.7 mol % Fe_2O_3 improved the water-vapor resistance drastically and decreased the thermal expansion coefficient without increasing T_9. Sealing at 360°C with our lead-free Fe_2O_3-added vanadate glass enabled practical airtight packaging on an electronic device.