A method and apparatus to minimize thermal impedance using copper on the die or chip backside. Some embodiments use deposited copper having a thickness chosen to complement a given chip thickness, in order to reduce or minimize wafer warpage. In some embodiments, the wafer, having a plurality of chips (e.g., silicon), is thinned (e.g., by chemical-mechanical polishing) before deposition of the copper layer, to reduce the thermal resistance of the chip. Some embodiments further deposit copper in a pattern of bumps, raised areas, or pads, e.g., in a checkerboard pattern, to thicken and add copper while reducing or minimizing wafer warpage and chip stress.