Methods for removing particles from etching chamber

1. A method comprising:

etching a wafer using an etching tool, wherein the etching tool comprises:

a wafer station, wherein the wafer is placed on the wafer station during the etching;

a dry etching chamber, with the wafer station in the dry etching chamber; and

a coating layer on an inner surface of the dry etching chamber, wherein the coating layer comprises a silicon-based oxide exposed to a vacant inner space of the dry etching chamber, wherein a gas-flow re-distributor located in the dry etching chamber redistributes gas flow during the etching, and the gas-flow re-distributor separates the dry etching chamber into a top portion over the gas-flow re-distributor and a bottom portion under the gas-flow re-distributor, and the gas-flow re-distributor comprises:

an inner edge encircling the wafer station;

an outer edge concentric with the inner edge; and

a plurality of through-holes between the inner edge and the outer edge, wherein the plurality of through-holes interconnect the top portion and the bottom portion of the dry etching chamber, and the gas-flow re-distributor comprises Y 2 O 3 at surface.

2. The method of claim 1 , wherein the coating layer comprises SiClO x , with x being three or four.

3. The method of claim 1 , wherein the inner edge of the gas-flow re-distributor has a center, and first ones of the plurality of through-holes closer to the center have smaller sizes than second ones of the plurality of through-holes farther away from the center than the first ones.

4. The method of claim 3 , wherein the plurality of through-holes has increasingly greater sizes with an increase in distances between the plurality of through-holes and the center.

5. The method of claim 1 further comprising:

after the wafer is etched, moving the wafer out of the dry etching chamber; and

removing the coating layer.

6. The method of claim 5 further comprising:

coating an additional coating layer on the inner surface of the dry etching chamber; and

etching an additional wafer in the dry etching chamber.

7. The method of claim 6 , wherein when the additional coating layer is coated on the inner surface of the dry etching chamber, the additional coating layer is not coated on the gas-flow re-distributor.

8. The method of claim 1 , wherein the gas-flow re-distributor is free from the coating layer.

9. A method comprising:

etching a wafer using an etching tool, wherein the etching tool comprises:

a dry etching chamber;

a coating layer on an inner surface of the dry etching chamber, wherein the coating layer comprises SiClO x , with x being three or four;

a wafer station in the dry etching chamber, wherein the wafer is placed on the wafer station; and

a gas-flow re-distributor located in the dry etching chamber, wherein the gas-flow re-distributor separates the dry etching chamber into a top portion over the gas-flow re-distributor and a bottom portion under the gas-flow re-distributor, and wherein the gas-flow re-distributor comprises:

an inner edge encircling the wafer station;

an outer edge concentric with the inner edge; and

a plurality of through-holes between the inner edge and the outer edge.

10. The method of claim 9 , wherein the gas-flow re-distributor is free from the coating layer.

11. The method of claim 9 , wherein a metal sputtered from the wafer during the etching is attached to the coating layer.

12. The method of claim 11 , wherein the dry etching chamber further comprises a quartz layer, and the coating layer is on an inner side of, and in contact with, the quartz layer.

13. The method of claim 11 further comprising:,

after the wafer is etched, removing the wafer from the dry etching chamber;

etching the coating layer;

coating an additional coating layer on the inner surface of the dry etching chamber; and

etching an additional wafer in the dry etching chamber when the additional coating layer is present in the dry etching chamber.

14. The method of claim 13 , wherein when the additional coating layer is coated on the inner surface of the dry etching chamber, the additional coating layer is not coated on the gas-flow re-distributor.

15. The method of claim 9 , wherein the gas-flow re-distributor comprises Y 2 O 3 as a surface layer.

16. A method comprising:

performing a plurality of cycles in a dry etching chamber of an etching tool, wherein each of the plurality of cycles comprises:

etching a wafer in the dry etching chamber;

removing a coating layer located on an inner surface of the dry etching chamber; and

re-coating an additional coating layer on the inner surface of the dry etching chamber, wherein in the re-coating, the additional coating layer is not coated on a gas-flow re-distributor located in the dry etching chamber, with the gas-flow re-distributor separating the dry etching chamber into a first portion higher than the wafer, and a second portion lower than the wafer.

17. The method of claim 16 , wherein each of the coating layer and the additional coating layer comprises a silicon-based oxide.

18. The method of claim 17 , wherein each of the coating layer and the additional coating layer comprises SiClO x , with x being three or four.

19. The method of claim 16 , wherein during the etching, a gas-flow re-distributor located in the dry etching chamber redistributes gas flow, wherein the gas-flow re-distributor separates the dry etching chamber into a top portion over the gas-flow re-distributor and a bottom portion under the gas-flow re-distributor, and the gas-flow re-distributor comprises a plurality of through-holes interconnecting the top portion and the bottom portion of the dry etching chamber.

20. The method of claim 19 , wherein the plurality of through-holes has increasingly greater sizes with an increase in distances between the plurality of through-holes and a center of the gas-flow re-distributor.