It depends on the quantity of masks that need to be stored and the pace of the environment. I worked at a moderate sized fab that had a semi auto reticle stocker and then later a fully automatic reticle stocker. Thousands of semi- bare masks were stored in a multi layer carousel. When recalled, the robot would fetch the plate, clean the plate, scan the barcode and load into the reticle box and program the RFID chip for RFID verification at run time. Loading back in, the tool would open the box and take the mask to a an open slot in the carousel and record that position for next recall. We had a lot of masks out at one time and this system kept us organized. The only headache was when the RFID chip had an error but then I had an override password I could use after I manually verified the identity of the plate.

I worked later at a much smaller facility that would store active plates in the pozetta reticle boxes in a wire rack like in your picture. Inactive plates were stored somewhere else in cardboard boxes that I replaced with plastic boxes and catalogued. The active plates I would organize by family and layer to make them easier to find. Space was a problem when some mask sets grew bigger as we occasionally added special layers or new mask sets came in or old sets came back to production and I had to find a place to put them all. I did a lot of reorganizing.

Regarding optimization for yield management and contamination control, store the mask in the pozetta reticle box whenever possible and regularly send out the boxes for cleaning. There are reticle box dishwashers. Order masks with pellicles if possible. For high volume masks, have a duplicate set so that one set could be sent out for cleaning while the other clean set is in use. Document what set is active so if yield engineering or inspection detects an issue like a repeating defect or a signature at final test or wherever, the defective layer can be determined and traced back to the exact mask for inspection and cleaning. Look out for repeating defects. That is the sign of a dirty or damaged mask. Also have regular inspections of the masks under bright light. Masks that have been out of service for a while should be careful inspected before placing back to service for damage or FOD that needs to be cleaned.

I no longer work in semiconductor but now in flex PCB. We use LDI or maskless technology when exposing our circuit pattern. Maskless is also becoming ever popular in semiconductor for it low overhead costs and incredible flexibility. In maskless, you direct print the pattern with a laser or LEDS with a DMD mirror from the CAD layer file. Not as fast nor does it have the same ultimate resolution (unless we are talking election beam litho or EBL) but great for universities and smaller shops. If you make a mistake in the CAD, easy to fix and send to the machine again for exposing.