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Introduction to etch chambers.
This section shows simplified schematics highlighting the many differences seen in chamber types.
 Chamber opened to inspect a wafer. Not much to see eh! |  Our chamber or reactor must be able to maintain a vacuum, pass RF, flow gases and be temperature controlled. |  Simple schematic of the important pieces. |
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 Remind ourselves what is required. |  This is what goes on. |  A very simple schematic. Power to one electrode the other grounded. This is what is known as a parallel plate CCP etcher. |
 Simple schematic for a plasma etcher and an RIE etcher. Ion bombardment is greatest on the electrode having the RF and greater on the smaller of the two. |  A more sophistocate schematic now with real values shown. |  Plasma etching process. ICP tool, Cl2 etching poly Si with a PR mask. Cl radicals, Cl2+ ion incident on wafer, SiF4 by-product. |
 Different types of configurations which also exist. |  MERIE, magnetic field generates higher density plasma and can improved uniformity in some cases. Many etch tool suppliers used B flelds before to increase plasma density and help with uniformity. |  |
 Simple CCP parallel plate reactor have limitations obviously. Faster processes with a greater process latitude can be had with a few key changes. |  In a CCP chamber, as you add more RF power, you get larger dc bias as well as the plasma density benefits. However some process cannot live with tooo much dc bias. |  ICP or TCP was an early improvement. This type chamber gives ~ 100x plasma density of the basic CCP tools. ICP chambers however use a far lower pressure regime, this somewhat reduces the full benefit of 100x plasma density. |
 |  These days ICP has more processes than the older CCP design. This is fortunate and convenient. There is more process develpment latitude with ICP tools. |  ECR used microwave frequencies ~2GHz and large magnets to confine the plasma. Hitachi have been the most successful with this style. |
 |  |  Remote plasma for PR strip, but can also be used for chamber cleaning. These days most tools run a chamber clean after each wafer. |
 Alternative chamber designs with different plasma sources. |  Helicon. Not used commercially as far as I know. |  Helicon. |
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