Coating for performance enhancement of semiconductor apparatus

Abstract

A plasma processing chamber having advanced coating for the showerhead and for an extended bottom electrode. The extended bottom electrode can be formed by one or more of the focus ring, cover ring, and plasma confinement ring. The extended electrode can be formed using a one-piece composite cover ring. The composite cover ring may be made of Al2O3 and include a Y2O3 plasma resistant coating. The plasma confinement ring may include a flow equalization ion shield that may also be provided with the plasma resistant coating. The plasma resistant coating of the extended electrode may have elements matching that of the showerhead.

Description

[0001]This application claims the priority of Chinese Patent Application No. 201210421964.4, entitled “COATING FOR PERFORMANCE ENHANCEMENT OF SEMICONDUCTOR APPARATUS”, filed with the Chinese Patent Office on Oct. 29, 2012, which is incorporated by reference in its entirety herein.BACKGROUND[0002]1. Field[0003]The subject invention relates to plasma processing chambers and, in particular, to chamber arrangements using coating for internal chamber parts, which enhance the performance of the plasma chamber.[0004]2. Related Art[0005]In plasma processing chambers, a showerhead is often used to inject the process gas. In certain plasma chambers, such as capacitively-coupled plasma chambers, the showerhead may also function as an electrode, coupled to either ground or RF potential. However, during processing the showerhead is exposed to the plasma and is attacked by the active species within the plasma, such as halogen plasma of CF4, Cl2, etc. This phenomenon is especially troublesome for ...

AI Technical Summary

Benefits of technology

The invention provides methods for improving the performance of showerheads by coating them with advanced plasma resistant coatings. These coatings can improve the service performance of the showerhead and enhance the quality of plasma processes. The methods involve depositing a thick, crack-free coating with a random crystal orientation using a series of thinner coatings. This multi-layer structure reduces stress and the risk of cracking and delamination. The roughness of the surface to be coated is important for reducing these issues. Overall, the invention enables the creation of better showerheads for use in plasma processes.

Problems solved by technology

This phenomenon is especially troublesome for showerheads having a chemical vapor deposited silicon carbide coating (CVD SiC).

As is known, during processing the plasma may be rather corrosive to the various elements of the chamber, especially the showerhead, since it forms a part of the capacitive RF power circuit.

Yttria (Y2O3) coating is believed to be promising; however, it has been very difficult to find a process that results in good coating, especially one that does not crack or generate particles.

However, conventional PS Y2O3 coating is formed by the sprayed Y2O3 particles, and generally results in a coating having high surface roughness (Ra of 4 micron or more) and relatively high porosity (volume fraction is above 3%).

The high surface roughness and porous structure makes the coating susceptible to generation of particles, which may contaminate the wafer being processed.

In addition, the particle will come out from the gas holes and dropped on the wafer when the as-coated shower head is used in the plasma process, as the plasma sprayed coating inside the gas hole is very rough and has poor adhesion to the substrate.

However, all these deposition processes have some technical limitations such that they have not been actually used to scale up for the deposition of thick coating on the chamber parts for the plasma attack protections.

For instance, CVD of Y2O3 can not be carried out on substrates that cannot sustain temperatures above 600° C., which excludes the deposition of plasma resistant coating on chamber parts that are made of aluminum alloys.

PVD process, such as evaporation, can not deposit dense and thick ceramic coating because of their poor adhesion to substrate.

Therefore, so far no satisfactory coating has been produced, that would have good erosion resistance, while generating low or no particles and can be made thick without cracking or delamination.

However, the ER drops at the wafer edge area, which induces an increased non-uniformity of the ER over the wafer surface.

The increase of non-uniformity limits the application of Y2O3 coated showerhead (SH) to actual etching process.

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