A method of forming a memory device is provided. In some embodiments, a memory cell is formed over a substrate, and a sidewall spacer layer is formed along the memory cell. A lower etch stop layer is formed on the sidewall spacer layer, and an upper dielectric layer is formed on the lower etch stop layer. A first etching process is performed to etch back the upper dielectric layer using the lower etch stop layer as an etch endpoint.