After exposing the etch stop material 130 through the openings 145, the exposed portions of the etch stop material 130 are removed to expose the underlying oxide materials 115, as shown in FIG. 6. The etch chemistry used to remove the exposed portions of the etch stop material 130 may be a different dry etch chemistry than that used to form the openings 145. Alternatively, the same dry etch chemistry may be used and conducted for an additional amount of time. Portions of the underlying oxide material 115 and conductive material 140 are then removed, extending the openings 145 through the oxide material 115 and into the conductive material 140 to form the contact holes 150. As described above for the openings 145, the contact holes 150 may have different depths depending on the depth of the conductive material 140 to which each contact hole 150 extends. The etch chemistry used to form the contact holes 150 may be the same as or different from the etch chemistry used to remove the portions of the etch stop material 130. For instance, the etch chemistry used to form the contact holes 150 may include two etch chemistries, one to remove the etch stop material 130 and another to remove the portions of the oxide materials 115 and the conductive materials 140. The contact holes 150 may have a depth within a range of from about 1 μm to about 15 μm, such as from about 2 μm to about 12 μm, from about 3 μm to about 11 μm, from about 5 μm to about 15 μm, or from about 1 μm to about 10 μm. The difference in depth between shallower contact holes 150 and the deeper contact holes 150 may be about 10 μm.