Local stress distribution is determined in polycrystalline silicon using micro-Raman spectroscopy. The microstructures are thin membranes over a thick porous silicon channel locally grown on bulk silicon. The effect of the width of the membrane on the distribution of the local stress is measured. The results show that annealing reduces the residual stress by an order of magnitude and that the tensile stress in the membrane has a sinusoidal dependence for the relatively narrow channels.