Specific Process Knowledge/Etch/ASE (Advanced Silicon Etch): Difference between revisions
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==The Bosch process:== | ==The Bosch process:== | ||
The Bosch process uses alternation between an etch cycle and a passivation cycle. In the case of the silicon etching on the ASE, an etch phase with SF<sub>6</sub> and O<sub>2</sub> alternates with a passivation phase with C<sub>4</sub>F<sub>8</sub>. | The Bosch process uses alternation between an etch cycle and a passivation cycle. Introducing a passivation step in an etch process is very beneficial for the control of the angle of the sidewalls in the etch process because it allows us to cover them with a protective layer that suppresses the isotropic etching. Combined with the high plasma density in the ICP chamber, the excellent sidewall control enables us to etch high aspect ratio structures quickly. | ||
In the case of the silicon etching on the ASE, an etch phase with SF<sub>6</sub> and O<sub>2</sub> alternates with a passivation phase with C<sub>4</sub>F<sub>8</sub>. The coil power is responsible for the dissociation of the gas molecules into highly reactive radicals. | |||
Two recipes have been optimized for the ASE. Their specification is on a 10 % etch load wafer with trenches. | Two recipes have been optimized for the ASE. Their specification is on a 10 % etch load wafer with trenches. | ||