Anodic bonding using Gorilla Glasses

For the first time, this paper investigates anodic bonding using the latest chemically-strengthened glass called Gorilla Glass (from Corning). Gorilla Glass has many excellent properties for MEMS/NEMS applications, including hardness (resistance to scratching), flexibility, high fracture toughness and antibacterial resistance. However, the high thermal expansion coefficient of Gorilla Glass (7.58ppm/°C) makes it doubtful for anodic bonding, where high temperature (200∼4000C) and high electrical field are applied to facilitate silicon to glass bonding. We show that the presence of the potassium ions at the surfaces of Gloria Glass not only makes the glass more resistant to damage but also facilitates the process of anodic bonding (including lower bonding temperature and voltage). With the proper cooling conditions, it is also feasible to develop silicon-glass microstructures based on the principle of stress engineering.