My research activity is within the LSPE (Large scale Polarization Explorer) experiment which aims to measure the polarization B-modes of the Cosmic Microwave Background at large angular scales. The mission is composed of two instruments: SWIPE and STRIP. STRIP is a ground-based telescope that will be installed at El Teide Observatory (Tenerife, Canary Islands). SWIPE is a balloon-borne experiment that will fly in a circumpolar long duration balloon mission during the polar night. My work revolves around fabrication and test of bolometer for the SWIPE instrument. The detectors are TES (Transition Edge Sensor) spider-web bolometers with a micromesh absorber. During the first year of my PhD I worked on defining the final characteristics of the detectors, getting ready for the final production. Now I am working on fabrication of the detectors for the flight model, testing them to verify that they meet the requirements of the experiment. I am also beginning to work on a model of the detector to compare the performance of our devices with the results of simulations.