Pre-Applied Inter Chip Fill Material and Process for Advanced 3D Chip Stack

To pursue further performance improvement of semiconductor devices, three-dimensional (3D) chip integration using TSV would be one of the key technologies. Inter Chip Fill (ICF), resin to fill gaps between chips, would be an important component for highly reliable and durable 3D integrated devices. Technology using the pre-applied ICF, designed for advanced 3D chip-stack with narrow gap of less than 10um-pitch TSV connections, was developed and successful stack of chips was demonstrated. This paper describes the characteristics of the fill resin material, process conditions required for the stack joining and the cause of mechanical stress within the stacked chip and required material features of the pre-applied ICF and device structure to reduce the stress.