Specific Process Knowledge/Etch/OES: Difference between revisions

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 '''The etch process:'''<br>
-As an example, let's take the etching of silicon by fluorine in one of the dry etchers. The fluorine is supplied to the system as SF<sub>6</sub> gas that is fed to the process chamber using mass flow controllers. Driven by the RF generators (both coil and platen) the plasma will decompose the gas in a series of dissociation and ionisation reactions to form fluorine radicals F<sup>*</sup>. In the areas on the wafer that are not covered by a mask, the exposed silicon atoms will be attacked aggressively by the fluorine radical to form volatile SiF. As such, the SiF will desorp from the wafer surface and eventually get pumped away.
+As an example, let's take the etching of silicon by fluorine in one of the dry etchers. The fluorine is supplied to the system by a carrier gas, in this case as SF<sub>6</sub>, that is fed to the process chamber using mass flow controllers. Driven by the RF generators (both coil and platen) the plasma will decompose the gas in a series of dissociation and ionisation reactions to form fluorine radicals F<sup>*</sup>. In the areas on the wafer that are not covered by a mask, the exposed silicon atoms will be attacked aggressively by the fluorine radical to form volatile SiF. As such, the SiF will desorp from the wafer surface and eventually get pumped away.
 '''The plasma:'''<br>
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-The plasma in the process chamber emits light; the RF field
+'''The intensity of the light:'''<br>
- that depends on what molecules are in the
+The intensity of the light will depend on whether the molecule is a reactant or an etch product:# Reactant: The concentration in the plasma:** The carrier gas flow rate** The RF power (both coil and platen)** The process pressure
- as the gas constituents are continuously pumped into excited rotational
+# Etch product:
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