A system for fluid processing substrate surfaces arrayed in a fluid having a process section with a frame having a plurality of process elements to process the substrate surfaces without contacting the substrate surfaces and a substrate holder assembly having a number of substrate holders and configured for transporting substrates as a unit. The substrate holder assembly and each of the substrate holders are configured for removable coupling to the process section frame, each substrate holder configured to hold at least one of the substrates. The process section frame has alignment features disposed so that, on coupling of the substrate holder assembly with the process section frame, the alignment features interface with each substrate holder of the substrate holder assembly and locate each substrate holder in repeatable alignment, at corresponding coupling of each substrate holder and the process section frame, with respect to a predetermined feature of the process section.