Recent trends of underfill resin for portable device were reviewed. In recent years, almost everyone in many countries has at least one or more portable devices such as mobile phone, smart-phone, and portable game consoles.
Since these devices are often used under extremely severe condition for various purposes, they are required to have resistibility toward variety of physical and environmental stress. Underfill is one of the effective solutions to protect portable devices from troubles caused by these stresses. The requirements for physical and chemical properties of underfill resins and recent technologies used are described.