Wafer backing member for mechanical and chemical-mechanical planarization of substrates

A chemical-mechanical planarization machine, comprising:

• a platen mounted to a support structure;
• a polishing pad positioned on the platen;
• a wafer carrier having a lower face with a perimeter and a retaining rim extending downward from the perimeter of the lower face, wherein the lower face and the retaining rim define a mounting cavity in which a wafer substrate may be mounted;
• and
• a wafer backing member having a body including an upper section abutted against the lower face of the wafer carrier and a lower section to abut against a backside of the wafer, the lower section being substantially rigid to inhibit flexing of the wafer and the upper section being resiliently compressible to cushion the backside of the wafer.

A method of planarizing a semiconductor wafer, comprising the steps of:

• providing a wafer carrier having a wafer holder and a wafer backing member positioned in the wafer holder, the wafer backing member having an upper section abutted against a lower face of the wafer holder and a lower section to abut against a backside of the wafer, the lower section being substantially rigid to inhibit flexing of the wafer and the upper section being resiliently compressible to cushion the backside of the wafer;
• mounting the backside of the wafer to the lower section of the wafer backing member;
• pressing the wafer against a polishing pad;
• and
• moving at least one of the wafer carrier and the polishing pad to impart relative motion therebetween as the wafer is pressed against the polishing pad.

A method for chemical-mechanical planarization of a semiconductor wafer, the method comprising the steps of:

• pressing the wafer against a polishing pad;
• moving at least one of the wafer and the polishing pad with respect to the other to impart relative motion therebetween as the wafer is pressed against the polishing pad;
• inhibiting deformation of the wafer with a first substantially rigid layer abutting a backside of the wafer as the at least one of the wafer and the polishing pad moves with respect to the other;
• and
• cushioning displacement between the backside of the wafer and a lower face of a wafer carrier to which the wafer is mounted with a second compressible layer abutting the first layer as the at least one of the wafer and the polishing pad moves with respect to the other.