| AVS 61st International Symposium & Exhibition | |
| Vacuum Technology | Tuesday Sessions |
| Session VT-TuM |
| Session: | Gas Dynamics, Modeling, and Pumping Systems |
| Presenter: | Jack McInerney, Lam Research Corp |
| Correspondent: | Click to Email |
The excellent cooling capabilities of the electrostatic chuck enable high power plasma etching of modern semiconductor devices. In order to maintain a uniform temperature across the silicon wafer, a thin layer of helium is inserted between the wafer and chuck. Some of this gas leaks out at the wafer edge, and the resulting flow of helium can lead to pressure drops that compromise the heat transfer uniformity of the chuck. Fluid dynamics modeling of the helium distribution is often used in the design phase to ensure uniform pressure under various scenarios.
Because of the small gaps and low pressures, the gas behind the wafer is in the transitional or molecular flow regime. Modeling electrostatic chuck designs then requires using very computationally expensive methods such as Direct Simulation Monte Carlo (DSMC). In this paper, a simplified modeling approach is developed that allows the pressure distribution to be modeled as a two-dimensional conductance problem. This is done by extending the conductance calculations used in one-dimensional vacuum piping networks. The accuracy of the method is compared to molecular flow modeling. The method is then used to model some chuck configurations.