Although IR detectors are old and well known devices, at present they have not reached the status of a mass-market product. The main reason is directly related to their lack of affordability. Fifteen years ago the latest generation of thermal infrared (IR) detectors, as large format focal plane arrays (FPA), appeared with very promising expectation. They have been called low cost detectors because they do not need cooling and, as a consequence, prices are sensitively lower. However, they are currently still not affordable. Issues related to packaging and processing are limiting the potential affordability of these type of devices. Meanwhile, the technology of uncooled photonic detectors such as polycrystalline lead salt detectors are evolving fast and now they are a real alternative in the field of cheap detectors. CIDA owns an innovative technology for processing low density polycrystalline PbSe FPAs. This technology presents some advantages compared to the standard technology, mainly for processing more complex devices, such as 2D arrays or multicolor detectors. Mass production and prices decrease depend strongly on the monolithic integration between detectors and read out electronics. The method developed makes possible to process monolithic devices without any fundamental limitation. This work presents the latest results obtained during a study of monolithic integration viability carried out in our laboratories. A complementary metal oxide semiconductor (CMOS) test circuitry was designed, processed and submitted to all PbSe processing with promising results. The next phase will consist of designing a proper CMOS circuitry and process sensors on top.