Edge profiling for process chamber shields
Process chamber shields having specially profiled edges exhibit increased lifetime in PVD and CVD deposition chambers. Edge profiling reduces flaking and delamination of materials deposited onto the shields, thereby prolonging shield life, and, consequently, reducing costs associated with deposition. In one embodiment, a shield having an edge portion terminating in a rounded tip, where the tip has high curvature and a small thickness, is provided. In another aspect, a shield having a concave portion connecting with an edge portion, where an upper (inner) surface of the edge portion forms a tangent plane to the upper (inner) concave surface of the concave surface, is provided. In yet another aspect, a shield with a tapered edge portion is provided. Shields, having profiled edges in accordance with these aspects and in accordance with combinations of these aspects, can better support deposited films, particularly films containing compressively stressed materials, such as metal nitrides.
1. A shield configured for protecting components of a vacuum process chamber from undesired deposition of a material, the shield comprising:
a main portion designed or adapted to connect to an element of the vacuum process chamber, the main portion comprising an upper main surface and a lower main surface, wherein the main portion has a first average thickness;
a generally perimetrically shaped edge portion connected with the main portion, wherein the edge portion has an upper edge surface connected with the upper main surface and a lower edge surface connected with the lower main surface, wherein the edge portion has a second average thickness;
and a tip portion forming the terminus of the edge portion within an interior space of the chamber, and connecting the upper edge surface and a lower edge surface, wherein the tip portion has a rounded profile, such that an arc-like shape connects the upper edge surface and the lower edge surface, and wherein the distance between the upper edge surface and the lower edge surface at the tip is less than the first average thickness, wherein at least a part of the main portion of the shield has a generally concave shape, comprising a concave upper surface, and wherein the upper surface of the edge portion of the shield forms a tangent plane to the concave upper surface of the main portion of the shield.
2. The shield of claim 1 , wherein the distance between the upper edge surface and the lower edge surface at the tip is less than about 0.1 inches.
3. The shield of claim 1 , wherein the distance between the upper edge surface and the lower edge surface at the tip is less than about 0.05 inches.
4. The shield of claim 1 , wherein the distance between the upper edge surface and the lower edge surface at the tip is less than about 0.02 inches.
5. The shield of claim 1 , wherein the first average thickness is greater than the second average thickness.
6. The shield of claim 5 , wherein the edge portion of the shield is tapered, such that thickness of the edge portion of the shield decreases from the interface with the main portion of the shield towards the tip.
7. The shield of claim 5 , wherein the first average thickness is at least about 0.2 inches.
8. The shield of claim 1 , wherein the radius of concave main portion of the shield is between about 0.1 and 10 inches.
9. The shield of claim 1 , wherein the length of the tangent from the tip to the interface with the concave central portion is between about 0.1 and 5 inches.
10. The shield of claim 1 , wherein the shield has a kit life of at least about 2,000 kWh.
11. The shield of claim 1 , wherein the edge portion of the shield has a variable thickness.
12. The shield of claim 1 , wherein the tip has a radius of curvature that is equal to half of the distance between the upper edge surface and the lower edge surface at the tip.
13. The shield of claim 1 , wherein the shield is adapted to be movable within the vacuum process chamber.
14. The shield of claim 1 , wherein the shield comprises a shutter.
15. A vacuum process chamber comprising the shield of claim 1 .
16. The vacuum process chamber of claim 15 , wherein the vacuum process chamber is a physical vapor deposition (PVD) chamber or a chemical vapor deposition (CVD) chamber.
17. A shield configured for protecting components of a vacuum process chamber from undesired deposition of a material, the shield comprising:
a concave portion comprising an upper concave surface and a lower surface, wherein the concave portion of the shield has a first average thickness;
an edge portion connecting with the concave portion, wherein the edge portion has an upper edge surface connecting with the upper concave surface and a lower edge surface connecting with the lower surface of the concave portion, wherein the edge portion has a second average thickness, and wherein the upper surface of the edge portion of the shield forms a tangent plane to the concave upper surface of the concave portion of the shield.
18. The shield of claim 17 , wherein the second average thickness is smaller than the first average thickness.
19. The shield of claim 17 , wherein the edge portion is tapered such that thickness of the edge portion decreases from an interface with the concave portion of the shield towards a tip at a terminus of the shield edge.
20. The shield of claim 17 , wherein both the upper surface and the lower surface of the concave portion are arc-like and concave.
21. The deposition chamber comprising the shield of claim 17 .
22. A shield configured for protecting components of a vacuum process chamber from undesired deposition of a material, the shield comprising:
a concave portion comprising an upper concave surface and a lower surface, wherein the concave portion of the shield has a first average thickness;
an edge portion connecting with the concave portion, wherein the edge portion has an upper edge surface and a lower edge surface, wherein the edge portion has a second average thickness; and
a tip portion forming the terminus of the edge portion within an interior space of the chamber, and connecting the upper edge surface and the lower edge surface, wherein the tip portion has a rounded profile, such that an arc-like shape connects the upper edge surface and the lower edge surface, and wherein the distance between the upper edge surface and the lower edge surface at the tip is less than about 0.2 inches.
23. The shield of claim 22 , wherein at least one of the upper edge surface and a lower edge surface is flat.
24. A method of shielding a vacuum process chamber from undesired deposition of a material during integrated circuit fabrication, the method comprising:
providing a wafer substrate and at least one shield as recited in claim 1 , claim 22 or claim 17 into the vacuum process chamber, wherein the shield is connected with a chamber wall or a wafer pedestal; and
depositing the material onto the substrate and onto the shield or etching the material from the substrate while depositing the material onto the shield, such that material deposited onto the shield does not flake or does not contaminate the substrate.
25. The method of claim 24 , wherein the vacuum process chamber is a PVD or a CVD process chamber.