Eliminating first wafer metal contamination effect in high density plasma chemical vapor deposition systems
Methods and apparatuses for conditioning chambers using a two-stage process involving a low bias and a high bias stage are provided. Methods also involve clamping a protective electrostatic chuck cover to a pedestal by applying a bias to the electrostatic chuck during the high bias stage while cooling the protective electrostatic chuck cover, such as by flowing helium to the backside of the cover.
1. A method comprising:
(a) performing a first stage comprising exposing a chamber to plasma to deposit a film on surfaces of the chamber while no wafer is present in the chamber at a first bias power, the first bias power applied to an electrostatic chuck in the chamber; and
(b) after performing the first stage, performing a second stage comprising exposing the chamber to plasma to deposit a second film on surfaces of the chamber while no wafer is present in the chamber at a second bias power,
wherein the second bias power is greater than the first bias power.
2. The method of claim 1 , wherein (b) further comprises clamping a protective cover to the electrostatic chuck and flowing a gas to a backside of the protective cover.
3. The method of claim 1 , wherein (b) further comprises cooling a protective cover on the electrostatic chuck.
4. The method of claim 1 , wherein (b) further comprises performing high density plasma chemical vapor deposition.
5. The method of claim 2 , wherein pressure of the gas flowed to the backside of the protective cover is less than about 3 Torr.
6. The method of claim 2 , wherein the protective cover comprises ceramic material.
7. The method of claim 2 , wherein the protective cover is clamped for at least about 10 seconds.
8. The method of claim 2 , wherein the protective cover is clamped at a clamping voltage of at least about 2000V.
9. The method of claim 1 , wherein the first bias power is less than about 1500 W.
10. The method of claim 1 , wherein the second bias power is at least about 2000 W.
11. The method of claim 1 , further comprising (c) after performing the second stage, exposing a wafer to plasma in the chamber to deposit a film by high density plasma chemical vapor deposition.