CARRIER HEAD WITH FLEXIBLE MEMBRANES TO CONTROL THE APPLIED LOAD AND THE DIMENSION OF THE LOADING AREA

摘要

A carrier head (300) for a chemical mechanical polishing apparatus includes two membranes (352, 350). The external membrane (352) includes a central portion (380) that provides a mounting surface to engage the substrate (10), a lip portion (382), and a perimeter portion (384) that extends in a convoluted path between the spacer rings (362, 364, 366) to be secured to the base assembly. The internal membrane (350) includes a central portion (370) that will contact the upper surface of the external membrane (352) in a controllable annular area, a relatively thick annular portion (372), an annular outer flap (374) that extends from the outer rim of the thick portion (372), an annular inner flap (376) that extends from the inner edge of the thick portion (372). The contact area of the internal membrane (350) against the external membrane (352), thus the loading area in which pressure is applied to the substrate (10), may be controlled by varying the pressure in the chambers (354, 356, 358) formed between the two membranes (350, 352) and the housing (302).