Photomask Fabrication

Photomasks at BNC are made on the Heidelberg MLA150 using a laser direct write process.

The mask production process flow is:

Design: Researcher designs layout in GDS, CIF, or DXF format using CAD program of choice.
Submission: NOTE: BNC is currently offering mask fabrication on an extremely limited basis, contact Joon Park for more information.
The previous procedure was:
1) Researcher submits a Photomask Fabrication Request in the Request Services tab in the BRK Lithography Core iLab page.
Verification: Staff converts layout into Heidelberg specific LIC file on cleanroom PC.
Acceptance: Researcher meets with staff in cleanroom or staff offices to inspect translated file and give final approval.
Fabrication: After final approval, masks will be completed within 5 business days. Fabrication consists of:
1. Writing: Staff member writes the appropriate plate on the Heidelberg, with total write time depending on the size of the design (the Heidelberg writes at ~12 mm²/min).
2. Wet Processing: The written plate is developed, etched, and the remaining PR is removed.
3. Inspection: Minimum feature size is inspected and recorded.
4. Completion: The completed photomask is placed in the dry box in cleanroom bay M. Researcher is notified electronically of completion.

Alignment mark examples: