A large-area photomask carries an extended active field on one substrate. It can contain a single large structure or an array of repeated units whose positions share a common coordinate reference.
Choose it when a panel, repeated array or long layout should be exposed in a common field compatible with the tool, rather than assembled from separately positioned exposures.
Large area describes field coverage. It can be combined with a glass or fused-silica substrate and with one mask or a multilayer set. Across a wider field, support, flatness and thermal expansion affect registration as well as local line quality.
Active field, repeated cell arrangement, border clearances, handling outline and distributed alignment marks are the main configuration choices.
The product is a patterned glass or fused-silica mask, or an identified set of masks for successive layers. Exposure equipment, photoresist-coated workpieces and the finished devices are separate from the mask itself. Inspection records and packaging form part of the order specification.
| Product configuration | Large-format chrome photomask with a defined active field |
|---|---|
| Reference field | Up to 205 × 205 mm or 410 × 410 mm, subject to configuration |
| Substrate format | Up to 9 × 9 in or 17 × 17 in, subject to fixture |
| Stitching reference | Stitching stability and full-field registration defined on the drawing |
| Acceptance focus | Active-field placement, flatness, stitching and edge exclusion |
Measure full-field registration, representative critical features, flatness and defects over the agreed active area.
Glass photomasks with an extended patterned area for larger exposure fields. Overall format, usable pattern area and registration requirements must be specified separately.
A larger mask can carry extended structures, repeated arrays and alignment references within one plate. Typical tasks include compatible display, sensor and patterned-glass processes. The functional area is the region that the exposure system can actually use, not the entire outside dimension.
Large fields make substrate shape, coordinate placement and handling more significant. Alignment features should be distributed for the process rather than placed only where there is spare space. Local feature checks and overall registration answer different inspection questions.
Manufacturing capability
Large-area masks use the writing field, substrate format and stitching plan as one design problem. The system reference includes exposure fields up to 205 × 205 mm or 410 × 410 mm and substrate formats up to 9 × 9 in or 17 × 17 in, subject to the selected configuration and fixture.
Choose glass or synthetic fused silica around the exposure wavelength, thermal requirements and fixture. State chromium optical density, reflectance, film-side orientation and allowed defect classes. The clear and opaque regions must be unambiguous in the approved artwork.
Quality & Inspection PhotolithographyFinished masks covering an extended exposure field.
Masks for larger panels and repeated layouts.
Usually not. Holding, alignment and edge exclusion can reduce the usable field. Specify both dimensions.
Large-area photomasks carry exposure patterns over an extended substrate for large-field pattern transfer.
Distinguish the substrate outline, active pattern area and location datums. Define alignment and inspection locations across the field.
Overall dimensions, active area, tiled or array relationships, alignment marks, substrate and inspection regions.
Not necessarily. Edges may be reserved for handling, cleaning or alignment. Dimension the substrate and usable exposure field separately.