Development of 4-sides buttable CdTe-ASIC hybrid module for X-ray Flat Panel Detector

The 4-sides buttable CdTe-ASIC hybrid module for X-ray Flat Panel Detector (FPD) has been developed by applying Through Silicon Via (TSV) technology to the readout ASIC. The ASIC has 128 × 256 channels of charge integration type readout circuit having the area of 12.9 mm × 25.7 mm. The CdTe sensor of 1 mm thickness, having the same area and pixel of 100 μm pitch, was fabricated from the Cl-doped CdTe single crystal grown by Traveling Heater Method (THM). Then the CdTe pixel sensor was hybridized with the ASIC using the bump-bonding technology. The basic performance of this 4-sides buttable module was evaluated by taking X-ray images, and it was compared with that of the commercially available indirect type CsI(Tl) FPD. A prototype CdTe FPD was made by assembling 9 pieces of the 4-sides buttable modules into 3 × 3 arrays in which the neighboring modules were mounted on the interface board with the gap less than 30 μm. The FPD covers an active area of 77 mm × 39 mm. The results showed the great potential of this 4-sides buttable module for the new real time X-ray FPD with high spatial resolution.