Planarizing machines, carrier heads for planarizing machines and methods for planarizing microelectronic-device substrate assemblies in mechanical or chemical-mechanical planarizing processes. In one embodiment of the invention, a carrier head includes a backing plate, a bladder attached to the backing plate, and a retaining ring extending around the backing plate. The backing plate has a perimeter edge, a first surface, and a second surface opposite the first surface. The second surface of the backing plate can have a perimeter region extending inwardly from the perimeter edge and an interior region extending inwardly from the perimeter region. The perimeter region, for example, can have a curved section extending inwardly from the perimeter edge of the backing plate or from a flat rim at the perimeter edge. The curved section can curve toward and/or away from the first surface to influence the edge pressure exerted against the substrate assembly during planarization. The second surface of the backing plate is a fixed, permanent surface. The backing plate can further include a permanent, low-friction coating over at least a portion of the perimeter region. The bladder is configured to extend over the second surface of the backing plate to form a fluid cell between the bladder and the second surface.
CROSS-REFERENCE TO RELATED APPLICATION
This application is a divisional of pending U.S. patent application Ser. No. 10/935,839, filed Sept. 7, 2004, which is a continuation of U.S. patent application Ser. No. 10/457,883, filed Jun. 9, 2003, now U.S. Pat. No. 6,787,055, which is a divisional of U.S. patent application Ser. No. 09/295,019, filed Apr. 20, 1999, now U.S. Pat. No. 6,227,955.
