What are the advantages of using a recess chuck versus a mechanical locating finger chuck when spinning square or rectangular substrates?
The non-vacuum, recess and the carrier recess chucks are designed for the end user who needs to have uniform coatings all the way to the edge of the substrate. These chucks have a recess pocket that is machined, at HRI’s machine shop, to the particular substrate dimensions and tolerances. Typically when using a recess chuck with our Inhibited Drying Spin Coating Kit, a better than 2% uniformity within a border of approximately .062″ from all the edges has been achieved. The mechanical locating finger chucks are designed to help center substrates. These chucks have four adjustable finger extensions to accommodate various substrate sizes. This chuck is recommended whenever protection of the backside of the substrates is not required by the end user. Uniform coatings can be achieved when using our Inhibited Drying Spin Coating Kit, however, turbulence at the finger extensions may have some affect on coatings.
