A finished chrome-on-glass photomask uses transparent windows and opaque chromium to form an exposure image. It transfers geometry through a photoresist process; the mask is the reusable pattern source, not the processed workpiece.
Choose a physical mask when the same layout will be exposed repeatedly, or when the exposure tool uses masks to align successive layers. It can support prototypes as well as repeated production.
A finished chrome-on-glass mask already carries the exposure pattern; a chrome blank does not. Compared with fused silica, other optical glasses can be suitable when the wavelength and thermal budget do not require the silica route.
Clear-field or dark-field layout, repeat arrays, marks, substrate outline and the contact or proximity use mode can be combined.
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 | Finished binary chrome-on-glass photomask |
|---|---|
| Pattern definition | Clear and opaque regions to approved artwork |
| Writing reference | Configuration I / II / III selected around feature size and field |
| Exposure route | Contact, proximity or other specified exposure method |
| Acceptance focus | Critical dimensions, placement, polarity and clear/opaque defects |
Check critical dimensions, placement, clear defects, opaque defects and pattern orientation against the approved artwork.
Patterned chromium on glass for optical pattern transfer. Specify clear and opaque regions, minimum feature size, pattern orientation and the exposure wavelength.
A chrome photomask divides the exposure field into transparent and opaque regions. In a compatible lithography process, light passing through the mask changes the photoresist so later development and processing can form the required geometry. The mask carries the design; the exposure process determines how it is reproduced.
A reusable glass master helps repeat the same artwork for optical components, sensor features and other patterned layers. Alignment marks, identification and polarity can be included with the functional geometry. It is different from an unpatterned chrome blank, which still needs the mask-writing process.
Manufacturing capability
The Heidelberg direct-writing route is suited to binary chrome-on-glass masks where clear and opaque regions must follow an approved artwork. The selected writing configuration, resist stack and chrome etch bias are reviewed together before release.
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 PhotolithographyOpaque/clear artwork for a compatible exposure process.
Terminology can depend on the exposure workflow. Provide a marked drawing showing exactly which regions must be clear and which must remain chrome.
Chrome-on-glass photomasks carry artwork as transparent and opaque regions for optical exposure and pattern transfer.
Confirm polarity, line width, spacing, viewing direction, exposure area and wavelength. Keep pattern and mechanical drawings on the same revision.
Artwork, exposure method, wavelength, substrate thickness, film-side orientation, active area and quantity.
Specify the viewing side and which way the patterned surface faces, including right-reading or mirrored artwork. The same pattern appears reversed when viewed from opposite sides.