A method of producing a device with a movable portion spaced apart from a support wafer comprises a step of providing the support wafer having a structured surface and a further step of providing a device wafer with a backing layer and a device layer disposed thereon. Further, the method comprises the step of generating a first planarization layer from a first starting material on the support wafer with a first method to fill in the structures of the structured surface of the support wafer, whereby a surface with a first degree of planarization is obtained. Further, the method comprises a step of generating a second planarization layer from a second starting material on the planarized surface of the support wafer with a second method to obtain a surface with a second degree of planarization, which is higher than the first degree of planarization, wherein the first and second planarization layers can be removed together. Additionally, the support wafer is connected to the device wafer such that the device layer and the planarized surface of the support wafer are connected. Then, removing the backing layer of the device wafer is performed, followed by structuring the resulting structure and removing the first and second planarization layers via a common method to generate the moveable portion of the device.
At temperatures near, and above, 385.degree. C., gold can diffuse into silicon and into some contact materials. Gold, however, is an excellent material because it is corrosion resistant, electrically conductive, and highly reliable. Using an adhesion layer and removing gold from the contact area above and around a contact allows a Micro-Electro-Mechanical Systems device or semiconductor to be subjected to temperatures above 385.degree. C. without risking gold diffusion. Removing the risk of gold diffusion allows further elevated temperature processing. Bonding a device substrate to a carrier substrate can be an elevated temperature process.
