The dual-gain 10 μm back-thinned 3k×3k CMOS-APS detector of the solar orbiter extreme UV imager

The Extreme Ultraviolet Imager (EUI) on-board the Solar Orbiter mission will provide image sequences of the solar atmosphere at selected spectral emission lines in the extreme and vacuum ultraviolet. For the two Extreme Ultraviolet (EUV) channels of the EUI instrument, low noise and radiation tolerant detectors with low power consumption and high sensitivity in the 10-40 nm wavelength range are required to achieve the science objectives. In that frame, a dual-gain 10 μm pixel pitch back-thinned 1k x 1k Active Pixel Sensor (APS) CMOS prototype has been tested during the preliminary development phase of the instrument, to validate the pixel design, the expected EUV sensitivity and noise level, and the capability to withstand the mission radiation environment. Taking heritage of this prototype, the detector architecture has been improved and scaled up to the required 3k x 3k array. The dynamic range is increased, the readout architecture enhanced, the power consumption reduced, and the pixel design adapted to the required stitching. The detector packaging has also been customized to fit within the constraints imposed by the camera mechanical, thermal and electrical boundaries. The manufacturing process has also been adapted and back-thinning process improved. Once manufactured and packaged, a batch of sensors will undergo a characterization and calibration campaign to select the best candidates for integration into the instrument qualification and flight cameras. The flight devices, within their cameras, will then be embarked on the EUI instrument, and be the first scientific APSCMOS detectors for EUV observation of the Sun.