Z shift modules

Linear modules for sample transfer and deposition height adjustment
The distance between the wafer cradle and the system mounting flange is usually specified by the customer to suit individual applications. An important feature in the EpiCentre 100 concept, is the option to insert single or multiple Z shifts (click here to view linear shift mechanism details) into the build to achieve varying levels of wafer manipulation. A single Z shift placed between MagiGear and the system mounting flange, will adjust the entire stage by moving both wafer cradle and heater along an axis normal to the substrate (Z axis). This is typically used to vary the deposition height.
By installing a single Z shift between MagiGear and the heater module service collar, the heater module may be retracted away from the wafer, hence providing a gap for manually extracting the sample. By installing both Z shifts, the stage may be manipulated in a typical wafer hand-off routine, as the heater may be retracted from the wafer to provide extraction space and the entire stage lifted or lowered to perform the wafer hand-off. These operations may be completed by hand rotated systems, motorisation or even pneumatically activated systems. A further option is the ‘double-Z shift’ (right), which will simply move the wafer cradle with respect to a fixed heater position. This is often the choice selected for production applications.

Examples of these options are illustrated below.
Simple stage using heating and rotation modules in fixed geometry. This set-up is typically used for hand manipulated wafer or sample loading.
When a linear shift mechanism is added between the mounting flange and MagiGear rotary feedthrough, the whole stage may be adjusted along the ‘Z’ axis. This is used for variable deposition stations and alignment requirements.
A linear shift mechanism placed between the MagiGear rotary feedthrough and the heater support flange will allow heater module separation from the wafer cradle. This allows wafer loading access but still requires the hand-off motion to be generated from an alternative mechanism.
With two independent linear shift mechanisms fitted, control is available over the heater and cradle separation together with the ability to shift the entire stage. This combination generates the motion required to exchange wafers or samples from a simple end effector positioned between the heater and cradle. The option of variable deposition geometry is still available with this combination.
This configuration is normally used for production style wafer hand-off motion. A single motorised (or hand wheel driven) linear shift mechanism manipulates the cradle for pick and place activity, while the heater module remains in a fixed geometry.