Flow Field Inside a Plasma Etch Reactor

Micro-electronic circuit wafers are typically manufactured using plasma etch reactors. Manufacturing is accomplished by depositing layers of conducting or insulating material onto a silicon wafer and then etching circuit features into them. The etch process involves bombarding the silicon wafer with a reactive neutral gas and an ion stream in a near-vaccum condition to carve out circuit features in a preferred direction. In order to improve the manufacturing process, increase yield, and raise quality, the flow field inside a chlorine plasma etch reactor is under study.

The goal of this research is to aid in the understanding of how the manufacturing control parameters affect the physical processes inside a low pressure plasma etch reactor. The flow inside the reactor varies from continuum flow to near free molecular flow. In addition, electromagnetic effects are important due to rf heating, magnetic confinement, and wafer potential bias acceleration. In order to correctly model the convective and diffusive transport as well as the chemistry and electromagnetic effects, particle methods (DSMC-PIC) are used. Computations are carried out on a massively parallel architecture IBM SP2. The work is done in collaboration with industrial partners who provide the specifics of reactor design and experimental data.

Numerical simulation allows the full characterization of both neutral and ion behavior inside the reactor. With simulation, it is also possible to study etch reactor design changes before building of hardware.

Acknowledgment

This work was funded by the Advanced Research Projects Agency (ARPA).

Publications