Non-contact cool-down station for wafers
A stationary cooling station for cooling wafers after the wafers have been subjected to semiconductor processing supports the wafer by flowing gas in accordance with the Bernoulli principle. An upper wall of the cooling station contains a plurality of gas outlets that direct gas to flow over the top surface of the wafer. In this way, a low-pressure region is created over the wafer and the wafer is suspended within the cooling station, without directly contacting any surface for support. In addition to providing lift for the wafer, the gas is a thermally conductive gas that can cool the wafer by conducting heat away from it.
1. A semiconductor wafer cooling station, comprising:
an upper horizontal surface;
a lower horizontal surface, wherein the lower horizontal surface and the upper horizontal surface define a wafer space configured to accommodate the semiconductor wafer; and
an immobile cooling assembly, the cooling assembly having a plurality of gas outlets configured to exhaust a gas onto a face of the wafer;
wherein the cooling assembly is configured to suspend the wafer by the Bernoulli principle utilizing the plurality of gas outlets, with both faces of the wafer vertically separated from the upper and the lower horizontal surfaces.
2. The cooling station of claim 1 , wherein the gas outlets are in gas communication with an inert gas source.
3. The cooling station of claim 2 , wherein the inert gas source contains nitrogen gas.
4. The cooling station of claim 2 , wherein the inert gas source contains a highly thermally conductive gas.
5. The cooling station of claim 4 , wherein the thermally conductive gas comprises helium.
6. The cooling station of claim 4 , wherein the thermally conductive gas comprises argon.
7. The cooling station of claim 1 , wherein the cooling assembly provides gas flow through the upper horizontal surface to the wafer space.
8. The cooling station of claim 7 , further comprising a showerhead to provide gas flow through the lower horizontal surface to the wafer space.
9. The cooling station of claim 1 , wherein the cooling assembly provides gas flow through the lower horizontal surface to the wafer space.
10. The cooling station of claim 1 , wherein each of the gas outlets is configured to emit the gas at an angle to create a low pressure region adjacent to the face of the wafer, in accordance with the Bernoulli principle.
11. A method of cooling a hot substrate that has been subjected to high temperatures in a chamber, comprising:
removing the hot substrate from the chamber with a substrate handler;
transferring the hot substrate into a stationary cooling station using the substrate handler;
vertically suspending the substrate inside the cooling station in accordance with the Bernoulli principle by flowing a gas to create a low pressure zone across a horizontal surface of the substrate; and
withdrawing the handler from the cooling station; and
convectively cooling the substrate by flowing the gas.
12. The method of claim 11 , wherein the gas comprises a highly thermally conductive gas.
13. The method of claim 12 , wherein the thermally conductive gas comprises helium.
14. The method of claim 12 , wherein the thermally conductive gas comprises argon.
15. The method of claim 11 , wherein convectively cooling the substrate further comprises flowing a gas to a side of the substrate opposite the horizontal surface.
16. The method of claim 11 , wherein convectively cooling the substrate comprises reducing a temperature of the substrate to about 60° C. or less.
17. The method of claim 16 , further comprising transporting the substrate to a wafer cassette after reducing the temperature of the substrate.