A device, such as a MEMS device, with stress tuning to achieve a desired stack stress across the wafer. The stress tuning includes trimming a stress compensation layer over a target layer having different stresses in different target layer regions. The trimming may include ion beam trimming to produce a stress compensation layer having different thicknesses over the different target layer regions to balance the stress of the target layer to a desired stress. The desired stress may result in almost zero residual stress to produce an almost flat MEMS device.