**Preface to "MEMS Packaging Technologies and 3D Integration"**

MEMS packaging is an essential technique for successful commercialization of MEMS products as MEMS has moving parts and an application-specific nature. A classic approach of MEMS packaging is to bond silicon or glass cap wafers to MEMS wafers. Therefore, it is typically implemented under high pressure and high temperature conditions. Advanced approaches use a thin-film deposition technique and then a cavity for MEMS is realized via sacrificial etch through access holes at the thin film cap. The packaging cap transfer technique is a compromise between the two approaches, since it makes it possible to bond and transfer a thin packaging cap to the released MEMS device. MEMS devices and IC are being integrated in a 3D fashion to achieve a better performance, and implantable devices need special packaging techniques. Thus, this Special Issue gathers research papers, short communications, and review articles that focus on MEMS packaging technologies and related integration methods. This Special Issue will help you to catch the trend of the recent MEMS or electronic device packaging and 3D integration technologies.

> **Seonho Seok** *Editor*
