Axcelis Technologies, Inc.

Shu Qin

Peter Lawrence Kellerman

Douglas A Brown

Ernie Allen

William F DiVergilio

The present invention is directed to a method and a system for clamping a wafer to a J-R electrostatic chuck using a single-phase square wave AC clamping voltage. The method comprises determining a single-phase square wave clamping voltage for the J-R electrostatic chuck, wherein the determination is based, at least in part, on a minimum residual clamping force associated with the wafer and the electrostatic chuck and a surface topography of a leaky dielectric layer associated therewith. The wafer is placed on the electrostatic chuck; and the determined clamping voltage is applied to the electrostatic chuck, therein electrostatically clamping the wafer to the electrostatic chuck, wherein at least the minimum residual clamping force is maintained during a polarity switch of the single-phase square wave clamping voltage. The determination of the surface topography comprises a first gap and a second gap between the wafer and the electrostatic chuck and an island area ratio, wherein a difference in RC time constants associated with the respective first gap and second gap is provided such that at least the minimum residual clamping force is maintained during the polarity switch. Upon removal of the square wave clamping voltage, the de-clamping time is substantially reduced, and corresponds to the pulse width of the square wave clamping voltage.

Clamping and de-clamping semiconductor wafers on a J-R electrostatic chuck having a micromachined surface by using force delay in applying a single-phase square wave AC clamping voltage

The present invention is directed to a semiconductor processing apparatus and a method for clamping a semiconductor substrate and controlling a heat transfer associated therewith. According to one aspect of the present invention, a multi-polar electrostatic chuck and associated method is disclosed which provides a controlled and uniform heat transfer coefficient across a surface thereof. The multi-polar electrostatic chuck comprises a semiconductor platform having a plurality of protrusions that define gaps therebetween, wherein a distance or depth of the gaps is uniform and associated with a mean free path of the cooling gas therein. The electrostatic chuck is permits a control of a backside pressure of a cooling gas within the plurality of gaps to thus control a heat transfer coefficient of the cooling gas. The plurality of protrusions further provide a uniform contact surface, wherein a contact conductivity between the plurality of protrusions and the substrate is controllable and significantly uniform across the substrate.

MEMS based multi-polar electrostatic chuck

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.

Clamping and de-clamping semiconductor wafers on an electrostatic chuck using wafer inertial confinement by applying a single-phase square wave AC clamping voltage

The present invention is directed to a method of forming a clamping plate for a multi-polar electrostatic chuck. The method comprises forming a first electrically conductive layer over a semiconductor platform and defining a plurality of portions of the first electrically conductive layer which are electrically isolated from one another. A first electrically insulative layer is formed over the first electrically conductive layer, the first electrically insulative layer comprising a top surface having a plurality of MEMS protrusions extending a first distance therefrom. A plurality of poles are furthermore electrically connected to the respective plurality of portions of the first electrically conductive layer, wherein a voltage applied between the plurality of poles is operable to induce an electrostatic force in the clamping plate.

Method of making a MEMS electrostatic chuck

The present invention is directed to a method for clamping and processing a semiconductor substrate using a semiconductor processing apparatus. According to one aspect of the present invention, a multi-polar electrostatic chuck and associated method is disclosed which provides heating or cooling of a substrate by thermal contact conduction between the electrostatic chuck and the substrate. The multi-polar electrostatic chuck includes a semiconductor platform having a plurality of protrusions that define gaps therebetween, wherein a surface roughness of the plurality of protrusions is less than 100 Angstroms. The electrostatic chuck further includes a voltage control system operable to control a voltage applied to the electrostatic chuck to thus control a contact heat transfer coefficient of the electrostatic chuck, wherein the heat transfer coefficient of the electrostatic chuck is primarily a function of a contact pressure between the substrate and the plurality of protrusions.

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Malden, MA, United States of America

Shu Qin