Who makes masks and blanks for AI data centers

A photomask carries the pattern that lithography projects onto the wafer; the blank is the coated quartz plate the mask is written onto. Every layer of every chip needs one, and the set of masks for an advanced logic device is one of the larger fixed costs of bringing a design to production — which is why a mask set is treated as a program commitment rather than a consumable. The part splits into two very different businesses that this catalog keeps together. Blanks are a materials business with an unusually short list of qualified suppliers at the most demanding grades, particularly for EUV, where defect requirements on the blank are severe. Mask writing and inspection is a service business, run either inside the fab's own mask shop or by merchant mask makers, and it turns around new revisions on a schedule that gates tape-out. AI changes the demand shape here more than the volume: accelerator and HBM roadmaps have compressed generation cycles, and each new design or shrink means a new mask set. What to look for is the split between captive and merchant capacity — much of the most advanced mask making happens inside the chipmakers themselves, so a merchant supplier's addressable share is narrower than the total. Blank supply and mask writing constrain separately; check which one a claim is about.