High-density plasma sources provide a number of advantages over conventional parallel plate plasma systems.
Disadvantages of Conventional Systems
In conventional RIE, the plasma density is limited by coupling RF energy into the plasma. This restricts the rates at which certain materials can be deposited or etched. This particular problem becomes very acute at low pressures, where with a RIE efficiency, the plasma density becomes extremely low. Traditional RIE plasma sources normally attain a plasma density in the 0.5 - 5.0 x 1010 cm-3 range. These sources typically show a decrease in plasma density and etch rate with a change in pressure. When an inductively coupled plasma source is used, it allows for higher plasma densities as power is transferred into the bulk plasma through the magnetic field resultant from inductively coupling. Lower pressure processing is beneficial in a number of ways. It enables tight control of anisotropy in high aspect ratio structures and reduces the effect of micro-loading.
Advantages of Inductively Coupled Plasma Sources
Inductively coupled plasma sources have several advantages over other high density sources that include the following:
- Design simplicity
- Less stringent requirements on operating pressures
- No need for magnetic field
- RF power supplied at lower frequencies than microwave systems
Applications of Inductively Coupled Plasma
Typical applications of this inductively couled plasmas are listed below:
- Oxide
- Deep silicon trench
- Polyimide
- Polysilicon
- Active devices effected by radiation
The figure below shows one of Trion’s systems shown with ICP option.
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Figure 1. The Minilock-Phantom III reactive ion etcher with vacuum loadlock.
Conclusion
It is possible to obtain enhanced etch rates and profile control, enhanced selectivity, improved evenness and a drastic reduction in contamination and radiation damage from RIE sputtering.
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This information has been sourced, reviewed and adapted from materials provided by Trion Technology.
For more information on this source, please visit Trion Technology.