WAFER HOLDING APPARATUS FOR CHEMICAL MECHANICAL POLISHING PROCESS

摘要

PURPOSE: A wafer holding apparatus for a chemical mechanical polishing process is provided to easily hold a wafer and improve polishing uniformity only by controlling an air pressure of a holding head. CONSTITUTION: A revolution axis connection unit receives revolution movement. The holding head includes the revolution axis connection unit and an air flow path(102). A plate(200) supplies a holding surface for holding the wafer(10), installed in a surface opposite to a polished surface of the wafer. The plate is detachably coupled to the holding head to form a space inside the holding head. At least one inner through hole is formed in the holding surface. The edge of a backing film(300) is fixed by the coupling of the holding head and the plate so that the backing film is closely supported by the holding surface. A one-way absorption unit is disposed in a position corresponding to the inner through hole in a direction from the outside to an inner space(103) of the holding head. A retainer(400) retains the outer circumference of the wafer absorbed to the backing film, surrounding the edge of the holding head. An inner connection hole is formed in the backing film, connected to the inner space. A hole extension part is formed near the inner connection hole. The one-way absorption unit has such a size to cover all of the hole extension part. A sealing layer is disposed inside the hole extension part so that the edge of the sealing layer is air-tightly attached to the backing film.