Method of making a device comprising at least one micro movable element provided above a cavity in said device and at least one hinge for said micro element and actuation electrodes for causing movement of said micro element, the method comprising the steps of: bonding together a substrate wafer, having a depression formed therein for providing enough space for the micro element to be able to deflect from a rest position without contacting surrounding structures, and a SOI wafer comprising a device layer, an oxide layer and a handle layer from which the micro element subsequently is to be made, the SOI wafer having a thinned down portion in the device layer made to define the thickness of said hinge, wherein the SOI wafer and the substrate are bonded together with the device layer facing the substrate wafer side where the depression is formed, whereby a closed cavity is formed between the wafers; removing the handle layer; providing first mask structures on the device layer defining a vent hole precursor structure, and performing a first etching through the first mask structure to a predefined depth so as to provide a vent hole precursor structure which extends down into the device layer of the wafer with out reaching the closed cavity; providing a second mask structure on the device layer defining the micro movable element and its hinge by opening up a contour in the second mask structure, performing a second etching through said second mask structures in a controlled way such that the vent hole precursor structure opens up to the cavity before the micro element and hinges have been finished, wherein the steps of etching vent holes and free etching the hinge structures are performed in the same step of second etching; and wherein the vent hole precursor structure and the micro movable element and hinges are formed in the device layer by performing the first and second etching, respectively. bonding together a substrate wafer, having a depression formed therein for providing enough space for the micro element to be able to deflect from a rest position without contacting surrounding structures, and a SOI wafer comprising a device layer, an oxide layer and a handle layer from which the micro element subsequently is to be made, the SOI wafer having a thinned down portion in the device layer made to define the thickness of said hinge, wherein the SOI wafer and the substrate are bonded together with the device layer facing the substrate wafer side where the depression is formed, whereby a closed cavity is formed between the wafers; removing the handle layer; providing first mask structures on the device layer defining a vent hole precursor structure, and performing a first etching through the first mask structure to a predefined depth so as to provide a vent hole precursor structure which extends down into the device layer of the wafer with out reaching the closed cavity; providing a second mask structure on the device layer defining the micro movable element and its hinge by opening up a contour in the second mask structure, performing a second etching through said second mask structures in a controlled way such that the vent hole precursor structure opens up to the cavity before the micro element and hinges have been finished, wherein the steps of etching vent holes and free etching the hinge structures are performed in the same step of second etching; and wherein the vent hole precursor structure and the micro movable element and hinges are formed in the device layer by performing the first and second etching, respectively.