US 6,547,559 B1 · Clamping of a semiconductor substrate for gas-assisted heat transfer in a vacuum chamber

Abstract

A method and apparatus are provided for supporting a semiconductor wafer in a vacuum and transferring heat by gas conduction between the wafer and a wafer chuck to facilitate wafer processing. The wafer substrate is loaded onto a seat plate, and then a clamp ring is lowered against the force of compression springs that bias the seat plate upward on guides extending upward from the body of the chuck. The clamp ring touches the wafer on the front or top side with an inner O-ring that is attached to the bottom of the clamp ring, and forces the wafer and the seat plate down to a lower position parallel to a heat transfer surface of the chuck, spaced therefrom by a narrow gap. In the lower position, an outer O-ring that is also attached to the bottom of the clamp contacts an outer sealing surface that surrounds the heat transfer surface, thereby enclosing a cavity that includes an annular chamber around the outside of the chuck and the narrow gap. Gas is supplied to the passage and thus to the gap. The gap and pressure may be such that a mean free path of the gas in the gap that is greater than the gap thickness, for example, 0.005 inches. Raising of the clamp ring allows the seat plate to raise to a transfer position to and from which a wafer is loaded or unloaded.

Claims16

Dependent claims

An apparatus for supporting a semiconductor wafer for vacuum processing comprising:

a heat transfer body having an upwardly facing heat transfer surface approximately corresponding in size to that of a semiconductor wafer to be processed, and an upwardly facing annular outer sealing surface;
a substrate seat member configured to support an upwardly facing semiconductor wafer to be processed thereon by contacting the backside of the wafer around its edge, the seat member being attached to the heat transfer body so as to move vertically thereon between a lower processing position spaced by a narrow gap from the heat transfer surface and an upper wafer exchange position, the seat member being resiliently biased toward the upper wafer exchange position;
an inner seal adapted to contact and form a gas tight seal against the wafer around the edge of the wafer;
a clamp ring vertically moveably supported above the substrate seat member adapted to contact the frontside of the wafer around the edge thereof and to force the wafer and seat member downward against the resilient bias to the lower processing position of the seat member and to form a gas tight seal between the wafer and the inner seal;
an annular outer seal between the outer sealing surface of the heat transfer body and the clamp ring positioned to form a gas seal between the annular outer sealing surface and the clamp ring when the seat member is forced to its lower processing position by the clamp ring;
the heat transfer body, the clamp ring and the seals enclosing a gas tight cavity that includes the gap.

3 more elements

An apparatus for processing a semiconductor wafer in a vacuum comprising:

a processing chamber;
a control system operable to maintain a vacuum of a processing gas in the processing chamber;
a substrate support mounted in the processing chamber and including:
a heat transfer body having an upwardly facing heat transfer surface,
a substrate seat member configured to support an upwardly facing semiconductor wafer to be processed thereon by contacting the backside of the wafer around its edge, the seat member being attached to the heat transfer body so as to move vertically thereon between a lower processing position spaced by a gap from the heat transfer surface and an upper wafer exchange position, the seat member being resiliently biased toward the upper wafer exchange position;
a clamp ring vertically moveably supported in the chamber above the substrate seat member and adapted to contact the wafer around the edge and to force the wafer and seat member downward against the resilient bias to the lower processing position of the seat member;
and
a seal positioned to contact the wafer around its edge and form a gas tight cavity that includes the gap between the heat transfer body and the wafer when the seat member is forced to its lower processing position by the clamp ring.

5 more elements

A method of supporting a semiconductor wafer for vacuum processing comprising:

resiliently maintaining a seat member biased toward an upper wafer exchange position above a heat transfer body having an upwardly facing heat transfer surface;
placing a semiconductor wafer, with a surface thereof to be processed facing upwardly, on the substrate seat member when in the upper wafer exchange position and supporting the wafer by contacting the backside of the wafer around its edge by the seat member;
moving a clamp ring from above the substrate seat member vertically downward, contacting, with an inner seal, the wafer around its edge and forcing, with the clamp ring, the wafer and seat member downward against the resilient upward bias applied to the seat member, to a lower processing position of the seat member in which the wafer is spaced by a narrow gap above the upwardly facing heat transfer surface of the heat transfer body;
and
forming a seal between the heat transfer body and the wafer when the seat member is forced to its lower processing position by the clamp ring and forming thereby a cavity that at least includes the gap.

2 more elements

Dependencies are inferred from the claim text.

Clamping of a semiconductor substrate for gas-assisted heat transfer in a vacuum chamber

Life of this patent

Clamping of a semiconductor substrate for gas-assisted heat transfer in a vacuum chamber

Life of this patent

Abstract

Claims16