Characterization of a broad beam Kaufman-type ion source operated with CHF3 and O2

The composition and ion energy distributions of the main ion species of an ion beam were recorded and analyzed. The RF-type broad beam ion source was operated with a mixture of CHF3 and O2. A plasma bridge neutralizer operating with Ar was employed for ion beam neutralization. The data were collected with an energy-selective mass spectrometer (ESMS). The mass spectrum showed numerous ion species, beginning with ionized molecules, dissociation products of the process gases and products from reactions with background gas and the plasma discharge vessel, and the extraction system. For a quantification of the ion beam composition, the mass dependent transmission functions for two ESMS were determined. The ion energy distributions show that, in comparison to operation with inert gases, there are additional slower ions present. These ions can be related to dissociation processes outside of the ion beam source. As a result of their typically lower etching yield, these slower ions affect the etching behavior.

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Influence of the RF-power on the etching yields and surface morphology in reactive ion beam etching of Si and photoresist

Rohkamm,

Spemann,

Scholze

et al. 2024

Journal of Applied Physics

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The change in ion energy distribution and composition of a reactive ion beam produced by an RF-excited ion beam source and operation with a mixture of CHF3 and O2 was investigated and correlated with the etching behavior. To this end, measurements were performed with an energy-selective mass spectrometer to determine ion energy distributions, current density measurements for the measurement of current density distributions of the ion beam, and tactile measurements to determine the etching rates of Si and photoresist. The morphology of the photoresist was measured with a scanning force microscope. In particular, alterations in the etching yield and surface morphology of the photoresist can be observed in response to changes in the applied RF-power. An increase in plasma density leads to an increase in fragmentation processes of the injected reactive gases, resulting in the formation of smaller fragments. These smaller fragments have a chemical impact on the substrate surface, which affects the etching performance. These effects can have significant consequences in the context of long-time reactive ion beam processing for patterning applications.

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Characterization of a broad beam Kaufman-type ion source operated with CHF3 and O2

Cited by 5 publications

References 14 publications

Adaptive processing strategy of pulse ion beam for sub-nanometer precision optical components

Adaptive processing strategy of pulse ion beam for sub-nanometer precision optical components

Characterization of an RF-excited broad beam ion source operated with a mixture of CHF3 and O2

Influence of the RF-power on the etching yields and surface morphology in reactive ion beam etching of Si and photoresist

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