Programmable MEMS diffraction gratings are used for spectroscopic applications because of their potential in tailoring visible and infrared spectra. A fully programmable MEMS diffraction grating (FPMDG), where every micro-mirror can move independently in a range 0 - λ/2, where λ is the wavelength of light, leads to a better control of the intensity for each wavelength in the synthetized spectrum – the intensity can take any value from 0 (micro-mirror λ/4-condition) to the maximum (no micro-mirror displacement). The FPMDG chip contains 64 micro-mirrors which are actuated electrostatically. Rigid Si micro-mirrors are connected to side electrodes via linkage arms, permitting the micro-mirror to follow a pure vertical displacement, reducing the micro-mirror bending throughout actuation. Microfabrication is based on a 4 mask photolithography process, using SOI and Pyrex wafers. Each micro-mirror of the FPMDG chip can move by 1.25μm at voltages below 100 V. Two families of micro-mirrors, 50μm or 80μm wide, show negligible cross-talk during actuation. The micro-mirror bowing is as small as 0.14 μm over 700 μm and remains unchanged throughout actuation. Extinction ratios of up to 100 have been achieved by actuating only 3 adjacent micro-mirrors. The measurements have shown high stability and good reproducibility over time. Finally, FPMDGs are used to demonstrate shaping of the input spectrum: the intensity in a particular wavelength region is controlled through independent actuation of a set of adjacent micro-mirrors. The result is attenuation or cancellation of the corresponding wavelengths.