Controlling etch rate drift and particles during plasma processing

Abstract

The invention is an plasma processing system with a plasma chamber for processing semiconductor substrates, comprising: a radio frequency or microwave power generator coupled to the plasma chamber; a low pressure vacuum system coupled to the plasma chamber; and at least one chamber surface that is configured to be exposed to a plasma, the chamber surface comprising: a YxOyFz layer that comprises Y in a range from 20 to 40%, O in a range from ≦60%, and F in a range of ≦75%. Alternatively, the YxOyFz layer can comprise Y in a range from 25 to 40%, O in a range from 40 to 55%, and F in a range of 5 to 35% or Y in a range from 25 to 40%, O in a range from 5 to 40%, and F in a range of 20 to 70%.

What is claimed is: 
     
         1 . A plasma chamber for processing semiconductor substrates, comprising:
 a radio frequency or microwave power source coupled to the plasma chamber;   a low pressure vacuum system coupled to the plasma chamber; and   at least one chamber surface that is configured to be exposed to a plasma, the chamber surface comprising:
 a YxOyFz layer that comprises Y in a range from 20 to 40%, O in a range from ≦60%, and F in a range of ≦75%. 
   
     
     
         2 . The plasma chamber of  claim 1 , wherein the YxOyFz layer that comprises Y in a range from 25 to 40%, O in a range from 40 to 55%, and F in a range of 5 to 35%. 
     
     
         3 . The plasma chamber of  claim 1 , wherein the YxOyFz layer that comprises Y in a range from 25 to 40%, O in a range from 5 to 40%, and F in a range of 20 to 70%. 
     
     
         4 . The plasma chamber of  claim 1 , wherein the YxOyFz layer was formed with an initial layer of Y2O3 exposed to an F-containing treatment. 
     
     
         5 . The plasma chamber of  claim 4 , wherein the F-containing treatment included HF, CF4, C4F8, C5F8, F2, or SF6. 
     
     
         6 . The plasma chamber of  claim 4 , wherein the F-containing treatment is performed in a wet chemical treatment using HF or a plasma treatment using CFw or F. 
     
     
         7 . The plasma chamber of  claim 1 , wherein the YxOyFz layer was formed with an initial layer of YF3 exposed to an oxygen-containing treatment. 
     
     
         8 . The plasma chamber of  claim 7 , wherein the O-containing treatment included O2, CO, CO2, H2O, or H2O2. 
     
     
         9 . The plasma chamber of  claim 1 , wherein the YxOyFz layer was formed with a YxOyFz compound in powder form. 
     
     
         10 . The plasma chamber of  claim 1 , wherein the YxOyFz layer was formed with Y2O3 in powder form wherein the Y2O3 powder was surface-modified with an F-containing treatment. 
     
     
         11 . The plasma chamber of  claim 1 , wherein the YxOyFz layer was formed with YF3 in powder form wherein the YF3 powder was surface-modified with an O-containing treatment. 
     
     
         12 . The plasma chamber of  claim 1 , wherein the YxOyFz layer was formed with a co-spray of Y2O3 in powder form and YF3 in powder form. 
     
     
         13 . The plasma chamber of  claim 1 , wherein the YxOyFz layer is a layer or a multi-layer that is formed by a plasma spray or a thermal spray comprising YF3 on top of a Y2O3 layer followed by thermal annealing. 
     
     
         14 . The plasma chamber of  claim 1 , wherein the YxOyFz layer is a layer or a multi-layer that is formed by a plasma spray or a thermal spray comprising Y2O3 on top of a YF3 layer followed by thermal annealing. 
     
     
         15 . The plasma chamber of  claim 1 , wherein the YxOyFz layer has a surface roughness of less than 1.6 μm. 
     
     
         16 . The plasma chamber of  claim 1 , wherein the YxOyFz layer or a mixture layer is formed by spraying particles of YF3 and Y2O3 with a ratio in a range of 0.1:1 to 10:1. 
     
     
         17 . The plasma chamber of  claim 1 , wherein the at least one chamber surface is a liner placed in the plasma chamber. 
     
     
         18 . The plasma chamber of  claim 1 , wherein percentages of Y, O, and F are controlled to achieve a target etch rate of the substrate and a target particle generation of yttrium hydroxide in the plasma chamber. 
     
     
         19 . A plasma chamber for processing semiconductor substrates, comprising:
 a radio frequency or microwave power generator coupled to the plasma chamber;   a low pressure vacuum system coupled to the plasma chamber; and   at least one chamber surface configured to be exposed to a plasma, the chamber surface comprising a YxOyFz layer that comprises F less than or equal to 75%,   O less than or equal to 60%, and Y less than or equal to 45%;   
       wherein percentages of Y, O, and F are controlled to achieve a target etch rate of the substrate and a target particle generation of yttrium hydroxide in the plasma chamber. 
     
     
         20 . The plasma chamber of  claim 19 , wherein the YxOyFz layer or a mixture layer is formed by spraying particles of YF3 and Y2O3 in a ratio in a range of 0.1:1 to 10:1. 
     
     
         21 . The plasma chamber of  claim 19 , wherein the at least one chamber surface is a liner placed in the plasma chamber. 
     
     
         22 . A method for plasma etching semiconductor substrates comprising;
 positioning a substrate within a plasma processing chamber comprising a surface of Y2O3;   flowing process gases comprising HBr and O2;   flowing a scavenger gas with the process gas, the scavenger gas comprising CFx.   
     
     
         23 . The method of  claim 22 , wherein the scavenger gas reacts with H in the plasma to minimize reactions between the H and the Y2O3. 
     
     
         24 . The method of  claim 22 , further comprising:
 controlling a composition of the YxOyFz layer to achieve a target yttrium hydroxide particle generation in the plasma processing chamber and a target etch rate of the substrate.