Hybrid Pixel Particle-Detector Without Bump Interconnection

A hybrid pixel particle-detector which does not require bump-interconnection is presented. The sensor signals are transmitted from the sensor to the readout chip using capacitive (AC) coupling. In order to facilitate the signal transmission, simple preamplifiers are implemented in the sensor pixels. The sensor chip with 100% fill-factor and in-pixel amplification is implemented in a standard high-voltage CMOS technology. Depleted high-voltage $n$-well/ $p$-substrate diodes are used as sensors. CMOS charge-sensitive amplifiers are placed inside the sensor-collecting electrodes ($n$-wells) using twin-wells. The outputs of the preamplifiers are connected to transmitter electrodes implemented in the top metal-layer of the sensor chip. The inputs of the receivers in the readout chip are also connected to electrodes in the top metal-layer. When the readout chip is precisely flipped and glued onto the sensor chip, the sensor- and receiver electrodes form capacitors that allow AC signal transmission. The first test results obtained with a small test-matrix containing 14 $\times$ 14 pixels of $78\times 60\ \mu{\rm m}^{2}$-size are presented. Noise, threshold dispersion and radioactive source spectra are measured.