In the development of pixel detectors for the HL-LHC ATLAS Inner
Tracking Detector upgrade (ITk), thin and finer granularity pitch planar
pixel detector has been developed by HPK/KEK and is ready for the
production. The hybridization optimization was started using the FE-I4
ASIC (250um x 50um pitch) for the current ATLAS pixel detector. Recently
a half size but final pitch readout ASIC, RD53A (50um x 50um pitch),
which is supposed to be the last prototype before the pre-production
chip, became available and the modules with this ASICs have been tested
in testbeam before and after irradiation.
In this presentation, I will summarize the progress in the HPK/KEK
hybridization development using sensor UBM and Sn/Ag solder bumps and
related sensor development targeting to implement on-pixel biasing
structures. The sensor module producton plan is also covered.