During deposition of thin film layers using shadow masking techniques, thin film layer structure morphology changes with respect to the position of the thin film layer and the shadow of the mask. Morphology changes in the thin film result in refractive index and density changes that affect the performance of the thin film layer in and around the shadow mask.
A robot was developed to ensure consistent thin film morphology over the entire surface area while utilizing shadow masking techniques. The two main figures of merit on the thin film consistency are density and refractive index. The robot allows for this by using masks that move during the deposition of the thin film.
The robot consists of three main parts: the backing mount that attaches the robot to the coating chamber planetary, the controlling electronics and motors, and the mechanism that holds and moves the masks during deposition. The robot is loaded into a thin film deposition chamber. During the deposition of a chosen layer, it is triggered to move the masking plates such that a taper or edge structure is created. This process can be changed or repeated over many different layers.
The primary feature of the robot is that it is programmable to run arbitrary profiles of thin film structures on many layers. Each robot is used only for one substrate, so many different profiles can be created within one coating run. In addition, the robot allows for the creation of arbitrary thin film structures while keeping the thin film characteristics uniform over the entire layer.