US Patent 10087525 Variable gap hard stop design

A reaction system for processing semiconductor substrates is disclosed. The reaction system includes a susceptor for holding the substrate as well as a baseplate as a part of housing for the reaction system. A pin located on the susceptor can interact with a baseplate feature located on the baseplate to result in a variable gap between the susceptor and the baseplate. The baseplate feature may take the form of a series of steps, a wedge, or a milled-out feature.