Vacuum compatible, deformable electrostatic chuck with high thermal conductivity

• US 6,215,642 B1
• Filed: 03/11/1999
• Issued: 04/10/2001
• Est. Priority Date: 03/11/1999
• Status: Expired due to Term

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Sogard, Michael
• Primary Examiner(s): SHERRY, MICHAEL JUDE
• Application Number:
  US09/266,705
• Time in Patent Office: 761 Days
• Field of Search: 361/233-235, 279/128
• US Class Current: 361/234
• CPC Class Codes: G03F 7/707 Chucks, e.g. chucking or un-chucking operations or structural details
• CPC Class Codes: G03F 7/70708 being electrostatic; Electrostatically deformable vacuum chucks
• CPC Class Codes: H01L 21/6831 using electrostatic chucks
• CPC Class Codes: H02N 13/00 Clutches or holding devices using electrostatic attraction, e.g. using Johnson-Rahbek effect

Abstract

A vacuum compatible, deformable electrostatic chuck with high thermal conductivity including a membrane having a layer of dielectric material, a layer of metallic film and a layer of semiconductor material with struts and a rim formed on the layer of semiconductor material. The rim is formed on the periphery of the layer of semiconductor material. The rim and struts contact a surface of a supporting structure forming a hollow area in which a coolant gas may be circulated. The supporting structure has gas manifold holes to connect the hollow area with a source of coolant gas. In a first embodiment, the struts have a rectangular cross section and are formed as a continuous structure from a first point on the rim to a second point on the rim. In a second embodiment, the struts are flexure struts having a first section with a rectangular cross section and a second section formed as a truncated cone or a pyramid.

Claims

1. A vacuum compatible, deformable electrostatic chuck with high thermal conductivity, comprising:

a supporting structure; and

a membrane comprising a first layer formed of a dielectric material, a second layer formed of a conductive material and a third layer formed of a substrate material and having a rim formed on a periphery of a surface of the third layer and multiple struts formed on the surface of the third layer, and wherein the membrane is attached to the supporting structure by the rim and the struts providing a hollow area between the membrane and a surface of the supporting structure, and wherein the supporting structure includes multiple gas manifold holes connecting the hollow area between the membrane and a surface of the supporting structure with a source of coolant gas.

2. The vacuum compatible, deformable electrostatic chuck with high thermal conductivity of claim 1 wherein the supporting structure includes a hollow structure, wherein the hollow structure is filled with a liquid coolant.

3. The vacuum compatible, deformable electrostatic chuck with high thermal conductivity of claim 2 wherein the hollow structure includes a top layer of material having a top surface interfacing with the rim and struts of the membrane and having a bottom surface having grooves that interface with the liquid coolant.

4. The vacuum compatible, deformable electrostatic chuck with high thermal conductivity of claim 1 wherein the third layer and struts is etched from a semiconductor wafer.

5. The vacuum compatible, deformable electrostatic chuck with high thermal conductivity of claim 2 wherein the second layer is formed from a conductive material selected from the group consisting of aluminum, titanium, tungsten, and copper.

6. The vacuum compatible, deformable electrostatic chuck with high thermal conductivity of claim 5 wherein the first layer is formed from a dielectric material selected from the group consisting of silicon dioxide, sapphire and an organic polymer.

7. The vacuum compatible, deformable electrostatic chuck with high thermal conductivity of claim 6 wherein the first layer has a thickness in the range of 20-100 μ

m.

8. The vacuum compatible, deformable electrostatic chuck with high thermal conductivity of claim 7 wherein the second layer has a thickness of approximately 50 nanometers.

9. The vacuum compatible, deformable electrostatic chuck with high thermal conductivity of claim 8 wherein the third layer has a thickness in the range of 10-20 μ

m.

10. The vacuum compatible, deformable electrostatic chuck with high thermal conductivity of claim 1 wherein the multiple struts are formed on the surface of the third layer from a first point of the rim to a second point on the rim.

11. The vacuum compatible, deformable electrostatic chuck with high thermal conductivity of claim 10 wherein the multiple struts have a rectangular cross section.

12. The vacuum compatible, deformable electrostatic chuck with high thermal conductivity of claim 11 wherein the multiple square shaped struts are formed on the surface of the third layer.

13. The vacuum compatible, deformable electrostatic chuck with high thermal conductivity of claim 12 wherein the multiple struts have a first section with a rectangular cross section and a second section in the shape of a truncated cone.

14. The vacuum compatible, deformable electrostatic chuck with high thermal conductivity of claim 12 wherein the multiple struts have a first section with a rectangular cross section and a second section in the shape of a pyramid.

15. An electrostatic chuck comprising:

a supporting structure including therein multiple gas manifold holes;

a membrane comprising,

a first layer formed of dielectric material,

a second layer formed of conductive material and

a third layer formed of a substrate material, the third layer having a rim formed on a periphery of a surface of the third layer and multiple struts formed on the surface of the third layer,

wherein the membrane is attached to the supporting structure by the rim and the struts, and

wherein the struts define a hollow area between the membrane and a surface of the supporting structure such that the multiple gas manifold holes connect the hollow area between the membrane and a surface of the supporting structure with a source of coolant gas.

16. An electrostatic chuck as in claim 15 wherein the supporting structure includes a hollow structure filled with liquid coolant.

17. An electrostatic chuck as in claim 16 wherein the hollow structure includes a top surface interfacing with the rim and struts of the membrane and including a bottom surface having grooves that interface with the liquid coolant, wherein the grooves are micro-machined into the bottom surface.