Indium Flip-Chip Packaging For X-ray Detector

X-ray detector is widely used in medicine, astronomy, security and other fields, and is very important that draws much attention. With the development of integrated circuit technology, the X-ray detectors today use large area, high density pixel arrays of silicon diode. That technology meets up a huge challenge of interconnection packaging between the sensor chip and the readout circuit chip.This article uses the hotspot of the flip-chip bonding to accomplish the X-ray detector pixels’packaging. Due to the density and points of the detector array that go beyond current mature flip-chip technology, there needs a lot of experiments to verify the feasibility and reliability of packaging.This thesis introduces the basic principle of X-ray detector and the basic flow of the flip-chip bonding process, designs the process flow and technology specifications that suitable for the design of the sensor chip and the readout chip. In particular, this thesis selects a not commonly used kind of metal "indium" as the solder, and designs a single layer thick negative photoresist lift-off method and the specified reflow temperature curve aiming at the indium ball fabrication. In addition, this thesis proposes a solder joint test method using a load capacitor, and makes it under the solder joint, then completes C-V characteristics test. Furthermore, this thesis takes some preliminary stress tests that verify the reliability of the welding. Finally, this article discusses the technology improvement in the future, and lays a foundation for further research.