Techniques for forming a magnetic device are provided. In one aspect, a method of forming a via hole self-aligned with a magnetic device comprises the following steps. A dielectric layer is formed over at least a portion of the magnetic device. The dielectric layer is configured to have an underlayer proximate to the magnetic device which comprises a first material, and an overlayer on a side of the underlayer opposite the magnetic device which comprises a second material. The first material is different from the second material. In a first etching phase, a first etchant is used to etch the dielectric layer, beginning with the overlayer, and through the overlayer. In a second etching phase, a second etchant which is selective for etching the underlayer is used to etch the dielectric layer through the underlayer.