Specific Process Knowledge/Etch/OES: Difference between revisions
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== Optical Emission Spectroscopy == | == Optical Emission Spectroscopy == | ||
'''The etch process:''' | '''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 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. | ||
'''The plasma:''' | '''The plasma:'''<br> | ||
The plasma emits light as the gas constituents are continuously exited | The plasma emits light as the gas constituents are continuously exited | ||
Revision as of 14:36, 26 November 2020
Optical endpoint detection on the dry etch tools at DTU Nanolab
Several dry etch tools at DTU Nanolab are equipped with an endpoint detection system. Out of those systems only one is not of the type optical endpoint detection. The instruments are:
- ICP Metal Etch
- III-V ICP
- Pegasus 1
- Pegasus 4
The section below describes the principle behind the optical endpoint detection system.
Optical Emission Spectroscopy
The etch process:
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 SF6 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*. 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:
The plasma emits light as the gas constituents are continuously exited
fdgsdfg
| Monitored species | Wavelength (nm) | Monitored species | Wavelength (nm) | |
| Al | 308.2, 309.3, 396.1 | In | 325.6 | |
| AlCl | 261.4 | N | 674.0 | |
| As | 235.0 | N2 | 315.9, 337.1 | |
| C2 | 516.5 | NO | 247.9, 288.5, 289.3, 303.5, 304.3, 319.8, 320.7, 337.7, 338.6 | |
| CF2 | 251.9 | O | 777.2, 844.7 | |
| Cl | 741.4 | OH | 281.1, 306.4, 308.9 | |
| CN | 289.8, 304.2, 387.0 | S | 469.5 | |
| CO | 292.5, 302.8, 313.8, 325.3, 482.5, 483.5, 519.8 | Si | 288.2 | |
| F | 703.7, 712.8 | SiCl | 287.1 | |
| Ga | 417.2 | SiF | 440.1, 777.0 | |
| H | 486.1, 656.5 |