Triboelectric charge controlled electrostatic clamp
An electrostatic clamp which more effectively removes built up charge from a substrate prior to removal is disclosed. Currently, the lift pins and the ground pins are the only mechanism used to remove charge from the substrate after implantation. The present discloses describes an electrostatic chuck in which the top dielectric surface has an embedded conductive region, such as a ring shaped conductive region in the sealing ring. Thus, regardless of the orientation of the substrate during release, at least a portion of the substrate will contain the conductive region on the dielectric layer of the workpiece support. This conductive region may be connected to ground through the use of conductive vias in the dielectric layer. In some embodiments, these conductive vias are the fluid conduits used to supply gas to the back side of the substrate.
1. A clamp for handling a substrate, comprising:
a top layer, made of non-conductive material;
a gas source;
a conduit embedded in said clamp adapted to carry gas from said gas source to said top layer, wherein a sidewall of said conduit is made of a conductive material;
an outer sealing ring, surrounding said top layer and extending above said top layer for supporting the substrate a distance above said top layer;
an outer conductive ring disposed on the outer sealing ring, the outer conductive ring and the outer sealing ring each having a surface in direct contact with the substrate, the outer conductive ring and the outer sealing ring being the only portions of the clamp configured to engage the substrate; and
a first conductive material deposited on said top layer between said outer conductive ring and said sidewall of said conduit, wherein said sidewall is in communication with ground.
2. The clamp of claim 1 , further comprising a second material deposited on top of said first conductive material.
3. The clamp of claim 2 , wherein said first conductive material comprises metal and said second material comprises a non-metallic electrically conducting material.
4. The clamp of claim 1 , further comprising a lower portion disposed beneath said top layer, wherein said lower portion comprises metal and is grounded, and said sidewall is in communication with said lower portion.
5. The clamp of claim 1 , further comprising a plurality of conduits arranged in a ring, each having a conductive sidewall, and an inner conductive ring embedded in or deposited on said top layer, electrically connecting said sidewalls of said plurality of conduits.
6. The clamp of claim 5 , comprising a plurality of connections between said inner conductive ring and said outer conductive ring.
7. The clamp of claim 5 , wherein said plurality of connections extends across a diameter of said top layer.
8. The clamp of claim 1 , wherein said clamp does not utilize ground pins.
9. A clamp for handling a substrate, comprising:
a top layer made of non-conductive material;
a conduit adapted to carry gas to said top layer, wherein a sidewall of said conduit is made of conductive material and is connected to ground;
an outer sealing ring extending around said top layer and extending above said top layer for supporting the substrate a distance above said top layer;
an outer conductive ring disposed on the outer sealing ring, the outer conductive ring and the outer sealing ring each having a surface in direct contact with the substrate, the outer conductive ring and the outer sealing ring being the only portions of the clamp configured to engage the substrate; and
a first conductive material deposited on an upper-most surface of said top layer and connecting said outer conductive ring to said sidewall of said conduit.
10. The clamp of claim 9 , further comprising a second material deposited on top of said first conductive material.
11. The clamp of claim 10 , wherein said first conductive material comprises metal and said second material comprises a non-metallic electrically conducting material.
12. The clamp of claim 9 , further comprising a lower portion disposed beneath said top layer, wherein said lower portion comprises metal and is grounded and said sidewall is in communication with said lower portion.
13. The clamp of claim 9 , further comprising a plurality of conduits arranged in a ring, each having a conductive sidewall, and an inner conductive ring embedded in or deposited on said top layer, electrically connecting said sidewalls of said plurality of conduits.
14. The clamp of claim 13 , comprising a plurality of connections between said inner conductive ring and said outer conductive ring.
15. The clamp of claim 13 , wherein said plurality of connections extends across a diameter of said top layer.
16. The clamp of claim 9 , wherein said clamp does not utilize ground pins.