CARBON DOPED METAL OXYFLUORIDE (C:M-0-F) LAYER AS PROTECTION LAYER IN FLUORINE PLASMA ETCH PROCESSES

Abstract

An article including: a substrate; and a protective film overlaying at least part of the substrate, the film including a fluorinated metal oxide, containing one or more elements of the Group III and/or Group IV elements of the periodical system of elements, characterized in that the protective film includes the fluorinated metal oxide with a carbon doping with a carbon concentration not lower than 0.1 at % and not higher than 10 at %, preferably not lower than 0.5 at % and more preferably not higher than 2.5 at %, wherein the article is a plasma etch chamber component and/or part and preferably an article of the group formed by electrostatic chuck, a ring, a process kit ring, a single ring, a chamber wall, a shower head, a nozzle, a lid, a liner, a window, a baffle or a fastener.

Claims

1. An article comprising a substrate a protective film overlaying at least part of the substrate, the film comprising a fluorinated metal oxide, containing one or more elements of the Group III and/or Group IV elements of the periodical system of elements, characterized in that the protective film comprises the fluorinated metal oxide with a carbon doping with a carbon concentration not lower than 0.1 at % and not higher than 10 at %, wherein the article is a plasma etch chamber component and/or part.

2. Article according to claim 1, characterized in that the metal of the protective film contains Yttrium.

3. Article according to claim 1, characterized in that the protective film has a coating thickness not less than 0.1 μm and not more than 30 μm.

4. Article according to claim 1, characterized in that the protective film has a roughness of Ra<1 μm.

5. Article according to claim 1, characterized in that the protective film has a reduced peak height of Rpk<0.25 μm.

6. Article according to claim 1, characterized in that the protective film has a hardness of at least 10 GPa as determined by nanoindentation with a fixed load of 5 mN, while the indentation depth is maintained below 10% of the coating thickness.

7. Article according to claim 1, characterized in that between the protective film and the substrate is an adhesion-promoting layer being a second metal or second metal oxide, where the metal of the film and second metal are identical.

8. Article according to claim 1, characterized in that the protective film comprises a gradient layer with increasing fluorine concentration measured from a deeper part of the protective film to a less deep part of the protective film and/or the protective film is a multilayer system comprising at least two layers with different fluorine concentrations with the fluorine concentration in the layer more distant to the substrate being higher than the fluorine concentration in the layer closer to the substrate.

9. Article according to claim 1, characterized in that the protective film comprises a gradient layer starting close to the substrate from pure M2O3 to (MaObFcCd), in which the concentration of MaObFcCd are chosen as follows: 0.25<a<0.4, 0.2<b<0.6, 0.1<c<0.6 and 0.01<d<0.1 with a+b+c+d=1.

10. Article according to claim 1, characterized in that between the protective film or if given the adhesion promoting layer and the substrate foreseen is a Y-containing thermally sprayed precoat, comprising Y2O3 and/or YOF.

11. Method for producing an article according to claim 1, characterized in that the protective film overlaying at least a part of the substrate is applied by Physical Vapor Deposition (PVD) and/or Chemical Vapor Deposition (CVD).

12. Article according to claim 1 wherein the carbon concentration is not lower than 0.5 at %.

13. Article according to claim 12 wherein the carbon concentration is not higher than 2.5 at %.

14. Article according to claim 1 wherein the carbon concentration is not higher than 2.5 at %.

15. Article according to claim 1 wherein the article is at least one of an electrostatic chuck, a ring, a process kit ring, a single ring, a chamber wall, a shower head, a nozzle, a lid, a liner, a window, a baffle, or a fastener.

16. Article according to claim 1, characterized in that the metal of the protective film is Yttrium.

17. Article according to claim 1, characterized in that the protective film has a roughness of Ra<0.25 μm.

18. Article according to claim 1, characterized in that the protective film has a roughness of Ra<0.025 μm.

19. Article according to claim 1, characterized in that the protective film has a reduced peak height of Rpk<0.10 μm.

20. Article according to claim 1, characterized in that the protective film has a reduced peak height of Rpk<0.025 μm.

Description

[0026] The figures show the following:

[0027] FIG. 1 shows the material composition of the films resulting from the two coating runs.

[0028] FIG. 2 shows different roughness values of the films coated on alumina, aluminum and silicon.

[0029] FIG. 3a shows the SEM of a cross section of a sample.

[0030] FIG. 3b shows the SEM of a part of the surface of a sample.

[0031] FIG. 4 shows the measured hardness and the E-modulus of the films resulting from the two coating runs.

[0032] In a first coating run aluminum and alumina (4μ-in. Ra) as well as silicon substrates were solvent cleaned and loaded onto a 2-axis of rotation planetary system inside a stainless-steel deposition system.

[0033] Argon plasma etching of substrates was performed using a DC filament discharge and pulsed DC substrate biasing.

[0034] The chamber was evacuated below 1E-2 mbar and an Argon flow regulated to 160 sccm was established.

[0035] Pulsed DC power was then delivered to a balanced planar Yttrium target starting at a 50% power setting and then ramping to 6 kW.

[0036] Reactive gasses O2 and CF4 were then used to deposit the C doped Yttrium Oxyfluoride (YOFC) coating. The ratio of CF4 to O2 was set to a ratio of 30:70. The reactive gasses are then adjusted at this set ratio slowly over a period of 5 min. so that the cathode voltage decreases steadily from 565V (pure metal film) to a final set point of 380V (fully oxy-fluoride doped carbon film). At this point the CF4/O2 ratio is still fixed. Minor adjustments in gas flow maintains the operating voltage setpoint on the sputtering cathode for the duration of the deposition. The conditions are thereby held at constant until the desired thickness of 2 μm is reached for the YOF functional top layer of the coating.

[0037] A second coating run was performed. All parameters but the CF4 to O2 ratio were the same as in the first coating run. The CF4 to O2 ratio was set to a ratio of 10:90.

[0038] FIG. 1 shows the resulting coating compositions for both coating runs determined by ERDA/RBS analysis. Coating composition is given in atomic ratio at. %. The detection limit is below 0.1 at. %. It can be seen that the C concentration is at 1.2 at % for both coatings. In contrast oxygen concentration goes down and fluorine concentration goes up if CF4/O2 ratio is increased.

[0039] XRD measurements revealed a rhombohedral crystalline structure of the coating.

[0040] Roughness measurements were performed on these with a stylus profilometer. The results are shown in FIG. 2. The inventive films seem to provide very small roughness values which might help to decrease the flaking effect. Remarkable as well are the small Rpk (reduced peak height) values. The coating surface does not provide for a topology with extraordinary peaks, it more resembles a hilly landscape. This as well can be seen from the SEM picture in FIG. 3b, taken as top view. FIG. 3a shows an SEM of a cross section of one of the samples.

[0041] The inventors performed as well hardness measurements on their samples which were carried out on a UNAT equipment (Universal Nanomechanical Tester). Hardness might insofar at least indirectly play a role as harder films have typically a higher density and are therefore less prone to be etched. The films were indented 45 times using a fixed load of 5 mN, while indentation depths are maintained below 10% of film thickness (Oliver and Pharr method rule). FIG. 4 shows the respective measurements.

[0042] Hardness and E-Modulus turned out to be in the same range as compared to prior art Y2O3 films, taken as reference.