Clamping and de-clamping semiconductor wafers on an electrostatic chuck using wafer inertial confinement by applying a single-phase square wave AC clamping voltage
First Claim
1. A method for clamping a semiconductor wafer to an electrostatic chuck, comprising:
- determining a single-phase square wave clamping voltage for the electrostatic chuck, wherein the determination is based, at least in part, on a wafer impact time;
placing the wafer on the electrostatic chuck, wherein a gap is defined between the wafer and the electrostatic chuck;
applying the determined single-phase square wave clamping voltage to the electrostatic chuck, therein electrostatically clamping the wafer to the electrostatic chuck; and
stopping the determined single-phase square wave clamping voltage, therein de-clamping the wafer from the electrostatic chuck.
5 Assignments
0 Petitions
Accused Products
Abstract
The present invention is directed to a method for clamping a wafer to an electrostatic chuck using a single-phase square wave AC clamping voltage. The method comprises determining a single-phase square wave clamping voltage for the electrostatic chuck, wherein the determination is based, at least in part, on an inertial response time of the wafer. The wafer is placed on the electrostatic chuck, wherein a gap between the electrostatic chuck and the wafer is defined. The determined single-phase square wave clamping voltage is then applied, wherein the wafer is generally clamped to the electrostatic chuck within a predetermined distance, while an amount of electrostatic charge is generally not allowed to accumulate, thereby enabling a fast de-clamping of the wafer.
-
Citations
20 Claims
-
1. A method for clamping a semiconductor wafer to an electrostatic chuck, comprising:
-
determining a single-phase square wave clamping voltage for the electrostatic chuck, wherein the determination is based, at least in part, on a wafer impact time;
placing the wafer on the electrostatic chuck, wherein a gap is defined between the wafer and the electrostatic chuck;
applying the determined single-phase square wave clamping voltage to the electrostatic chuck, therein electrostatically clamping the wafer to the electrostatic chuck; and
stopping the determined single-phase square wave clamping voltage, therein de-clamping the wafer from the electrostatic chuck. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
-
-
13. A system for clamping a wafer, comprising:
-
an electrostatic chuck comprising one or more electrodes operable to provide an electrostatic clamping force between a surface thereof and the wafer, the electrostatic chuck further having an RC time constant and a repelling force which is generally opposite the clamping force associated therewith, wherein a predetermined escape distance is generally defined by a wafer impact time, wherein the wafer impact time is further associated with the RC time constant of the electrostatic chuck; and
a power supply configured to provide a single-phase square wave clamping voltage to the one or more electrodes. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
-
Specification