Qualification and Integration Aspects of the DSSC Mega-Pixel X-Ray Imager

The focal-plane module is the key component of the DEPFET sensor with signal compression(DSSC) mega-pixel X-ray imager and handles the data of 128 $\times512$ pixels. We report on assembly-related aspects, discuss the experimental investigation of bonding behavior of different adhesives, and present the metrology and electrical test results of the production. The module consists of two silicon (Si) sensors with flip-chipconnected CMOS integrated circuits, a Si- heat spreader, a low-temperature co-fired ceramicscircuit board, and a molybdenum frame. A low-modulus urethane-film adhesive fills the gaps between on-board components and frame. It is also used between board and heat spreader, reduces the misfit strain, and minimizes the module warpage very efficiently. The heat spreaderreduces the on-board temperature gradient by about one order of magnitude. The placement precision of the bare modules to each other and the frame is characterized by a standard deviation below 10 and 65 $\mu \text{m}$ , respectively. The displacement due to the in-plane rotation and vertical tilting errors remains below 80 and 50 $\mu \text{m}$ , respectively. The deflection of the sensor plane shows a mean value below 30 $\mu \text{m}$ with a standard deviation below 15 $\mu \text{m}$ . Less than 4% of the application-specified integrated circuits (ASICs) exhibit a malfunction. More than two-thirds of the sensors have a maximum leakage current below 1 $\mu \text{A}$ .