Wafer carrier assembly for a chemical mechanical polishing apparatus and a polishing method using the same

A wafer carrier assembly for a chemical mechanical polishing apparatus, comprising:

• a first plate having a plurality of protrusions formed on a surface thereof;
• a second plate located under said first plate and having a plurality of apertures passing through, each of said apertures matched with one of said protrusions of said first plate to enable said first plate and said second plate to detachably combine together;
• and
• a flexible membrane positioned under said second plate, a first surface of said flexible membrane contacting a surface of said second plate and a second surface of said flexible membrane opposite said first surface providing a wafer-receiving surface;
• wherein when said first plate is separated from said second plate and a vacuum is turn on there-between, a plurality of vacuum spaces are formed under said second surface of said flexible membrane beneath said apertures of said second plate to provide vacuum-chucking for a semiconductor wafer.