Patent ID: 7303466

Claim:
A carrier head for chemical mechanical polishing equipment, comprising: a support having a bottom surface; an elastic membrane secured to said support and spaced from the bottom surface of said support so that a pressure chamber is defined between the membrane and the bottom surface of the support; and an annular barrier of elastic material extending from the bottom surface of said support, said barrier having an annular partition portion that extends through said pressure chamber and divides the pressure chamber into respective pressure zones on opposite sides of the annular partition, and an annular contact portion that extends from a lower end of said partition portion, said contact portion having a bottom surface that abuts said membrane such that the barrier contacts the membrane but is not fixedly attached thereto, and said contact portion comprising a pair of annular flanges extending laterally in opposite directions at the lower end of said partition portion, each of said flanges having a cross section that tapers to a point in the direction from which the flange extends from the partition portion, whereby fluid pressure in the pressure zones can deflect the flanges to maintain the entire bottom surface of the contact portion in contact with said membrane.