Direct writing is one kind of micro-fabrication technologies which can realize materials fabrication and processing in a broad range of size from sub-micrometer to several centimeters without masks. Direct ink writing, inkjet printing and direct laser writing are the most widely used direct writing technologies which enable fast and accurate fabrication of structures with high resolutions. A variety of materials including metals, ceramics, polymers and hydrogels can be processed for the formation of complicated two and three-dimensional architectures by these techniques. Therefore, they are widely used in many different fields such as microelectronics, tissue engineering, microfluidics and so on. In this review, we summarize the materials and principles of the three direct writing techniques, discuss their advantages and disadvantages, and then focus on their applications on microelectronics. An overview of the state-of-art developments in this area is given, the main challenges are discussed and the future trends is predicted. © 2017, Materials Review Magazine. All right reserved.
