Quality Inspection Aspects of Hybrid Prototypes for the CMS Outer Tracker Upgrade at HL-LHC

At the High Luminosity LHC (HL-LHC), the CMS experiment will need to operate at up to 200 interactions per 25 ns beam crossing time and with up to 4000 fb-1 of integrated luminosity. To achieve the physics goals the experiment needs to improve the tracking resolution and the ability to selectively trigger on specific physics events. The CMS tracker upgrade requires designing a new detector to cope with the HL-LHC conditions. The new Outer Tracker is based on two types of silicon modules (strip-strip and pixel-strip). Each module type has a few types of high-density interconnect hybrid circuits which house the front-end and auxiliary electronics. This paper introduces the technological choices for modules and hybrids and presents the quality inspection aspects of the first hybrid prototypes.