Cleaning etching reactors

Step 2. A dual-armed robot (e g., an Endura VHP robot by Applied Materials) transfers one wafer to the plasma-etch reactor in 20 s. The robot is encased within a transport module that is evacuated to 1 torr. Based upon the Trikon Sigma fxp Deposition Cluster, it is estimated that 35.1 ft2 of 100-level clean room area are required. 

Plasma Cleaning of CVD and Etching Reactors in Micro-Electronics... 

The etch cycle is performed at the end of the growth cycle and on new quartz reactors to clean the interior surface of impurities. 

This reaction is not a simple one. There are a number of intermediate chlorosilanes generated by competing reactions (10). The process is sensitive both to the thermodynamics and kinetics of the chemical reactions, and to the fluid mechanics (qv) of the gas flow in the reactor. The overall procedure involves purging the reactor with hydrogen gas, raising the temperature of the reactor, cleaning the wafers with a brief HC1 etch, and replacing the HQ with the silicon source gas. A complete process cycle can take up to an hour. 

Secondly, the wafer must be very "clean." Even a clean substrate will have 20 to 50 A layer of native oxide on it, and/or some carbon, and this will be enough to impede nucleation and give rise to many defects.1S After wafers are cleaned and inserted into the reactor, there is still the oxide layer to be removed as well as possibly some carbon on the surface. The traditional way of dealing with this phenomena is to operate a high-temperature HCI (1200°C) etch before attempting depositions. This etches away the native oxide, and any carbon on the surface diffuses into the bulk at this temperature. 

Wet Chemistry For sub-micron interconnect systems wet etching of tungsten is not a viable way to pattern tungsten lines. However, to clean reactor parts, or to reclaim or repair (8") precious wafers, a good wet etch chemistry is of importance. 

Growth processes should be conducted in chemically clean environments. There should be no interaction of the plasma with any element of the reactor, because the plasma can etch materials and transport them to the growing substrate. In general, any etching should be eliminated, and only diamond growth should occur. Hot filaments are not advised for homoepitaxial growth, due to contamination of the diamond by materials from the filament. Dust particles originating inside the system should be eliminated because they can provide secondary nucleation sites. 

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