Cleaning of plasma chamber walls using noble gas cleaning step
View Patent ↗An improved reaction chamber cleaning process is provided for removing water residues that makes use of noble-gas plasma reactions. The method is easy applicable and may be combined with standard cleaning procedure. A noble-gas plasma (e.g. He) that emits high energy EUV photons (E>20 eV) which is able to destruct water molecules to form electronically excited oxygen atoms is used to remove the adsorbed water.
1. A method for removing water residues from a surface of a material in a plasma chamber, the method comprising:
exposing a surface of a material in a plasma chamber to a noble gas plasma, wherein the noble gas plasma emits at least one of extreme ultra violet and vacuum ultra violet photons having sufficient energy to cause photolysis of water molecules adsorbed to the surface of the material, so as to release at least one of oxygen radicals, hydrogen radicals, and hydroxyl radicals;
detecting an amount of at least one of released oxygen radicals, released hydrogen radicals, and released hydroxyl radicals by at least one of optical emission spectroscopy, laser induced fluorescence, and mass spectrometry, wherein the detecting is conducted during exposing the surface of the material in the plasma chamber to the noble gas plasma; and
removing the radicals from the reaction chamber, such that re-deposition of water residues on the surface of the material is avoided.
2. The method of claim 1 , wherein detecting an amount of at least one of released oxygen radicals, released hydrogen radicals comprises detecting released oxygen radicals using optical emission spectroscopy at 777 nm.
3. The method of claim 1 , wherein the noble gas plasma is a He plasma.
4. The method of claim 1 , wherein the step of exposing a surface of a material in a plasma chamber to a noble gas plasma is performed using a noble-gas pressure of from about 0.39 Pa to about 10.66 Pa, at a noble-gas flow rate of from about 100 sccm to about 1500 sccm, and at a plasma power of from about 400 Watt to about 2000 Watt.
5. The method of claim 1 , further comprising a step of performing a waferless auto cleaning procedure using at least one of an O 2 /SF 6 plasma and an O 2 /Cl 2 plasma, wherein the step of performing is conducted before the step of exposing a surface of a material in a plasma chamber to a noble gas plasma.
6. The method according to claim 1 , wherein water residues are removed from at least one inner wall of a reactive ion etching chamber using at least one of a He plasma and an Ar plasma.
7. The method according to claim 1 , wherein the method is performed “in-situ”.
8. The method according to claim 1 , wherein the step of exposing is carried out for a time period of 15 seconds to 100 seconds.
9. The method according to claim 1 , wherein the step of exposing is carried out for a time period of 20 seconds to 100 seconds.