Module development for the HL-LHC ATLAS ITk Pixel upgrade

For the Large Hadron Collider (LHC) Phase 2 upgrade ATLAS replaces its current inner detector with an all silicon Inner Tracker (ITk) to achieve high performance in a very high occupancy and radiation environment. It consists of strip and pixel modules. Here the focus is placed on the assembly and testing procedures needed to assure the quality of the pixel modules to be installed in the detector. Ongoing developments and activities are discussed, e.g. with a special focus on the effect of mechanical stress in the connection of sensor and readout chip in the module due to thermal effects.