Planetary & Dome Fixturing
There are a variety of configurations available for fixturing multiple substrates in a physical vapour deposition system. A carefully designed substrate fixture can optimize throughput, uniformity, yield, and/or deposition geometry. What follows are three commonly used techniques.
Lift-off processes require an orthogonal geometry (right-angles) between the patterned substrate plane and the incoming flux of material to be deposited. Using computer modeling of these geometries, lift-off fixturing can be designed which optimizes the substrate angle and maximizes the number of substrates that can be processed in a single batch.
Planetary fixturing adds a second axis of substrate rotation which results in excellent film thickness uniformity. Individual rotating planets are arranged in orbit around a central rotation axis with a non-integral gear ratio. Each time a planet passes through a given position along the orbit, it will do so at a different radial position. The non-repeating nature of this rotation motif leads to film thickness uniformities often better than 1%.
Three dome rolling fixturing maximizes the throughput and yield of a deposition chamber by fully populating the deposition flux with substrate area. Additionally, the rolling dome provides two axes of rotation which ensures high film thickness uniformity.