Photomask Fabrication


The first step to submitting a photomask for fabrication is to register as a nanoFAB user. Once you have completed the account registration steps, you can proceed to the steps below:

1. Authorize mask submission

Due to the relatively high cost of mask fabrication, mask submission must be authorized by the primary account holder for each project under which the fabrication request is being submitted. This can be done in two ways:

  1. Project managers can directly authorize photomask submission for their project users within LMACS. From the Manage menu, choose Managed Projects, select the desired project, and click Users. Click the infoicon icon next to the desired user, switch the Can Submit masks slider from No to Yes, and optionally add a limit to the number of masks that the user can submit in the Mask Limit field; leaving this field as 0 allows for unlimited mask submissions by the user. Finally, click the Update button to implement the changes.
  2. OR
  3. Users can download a Mask Authorization Form, then upload a completed, signed copy of the form an LMACS request: create a new request of Administration request type, and attach this form to the request using the Add File(s) button.

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2. Get trained on GDSII pattern design (optional)

In some cases, you may have a photomask design already provided to you by a colleague; in others, however, you may need to construct a photomask design yourself. To this end, the nanoFAB supports two GDSII layout software options: L-Edit and KLayout.

L-Edit

L-Edit is a commercial layout tool, available on several computers in the nanoFAB design area for the convenience of our users. It is not necessary to be “signed off” before you begin using L-Edit. Training for L-Edit is offered online in the form of a series of videos with an accompanying guide.

All of the videos are available on our YouTube channel. You can find them embedded in our website below.

Watch the Videos Now Download the Fabrication Guide

If you have further questions regarding L-Edit after viewing the videos and reading the fabrication guide, please contact Michael Hume.

KLayout

KLayout is a free, open-source GDSII viewer and editor. It is available on several computers in the nanoFAB design area, but may also be downloaded and installed on any user’s own computer. A very good tutorial on using KLayout is available from the Washington Nanofabrication Facility.

If you have further questions regarding KLayout after viewing the above tutorial and the official KLayout documentation, please contact Aaron Hryciw.

Please note that the nanoFAB does not offer any design verification services.

3. Submit a GDSII file

Once you have a completed GDSII file, you can submit your mask for fabrication via LMACS:

  1. Login to LMACS.
  2. Click the Photomasks navigation button, found near the top of the page.
  3. Enter the appropriate information in the Mask Details section (project, name of cell to be printed, GDSII file, mask type, lens type, etc.). Additional information can be found by expanding the grey info boxes at the right side of the screen (General Instructions, Project, GDSII File, …).
    If the “Select Project” drop-down menu is empty, you need to get authorized on a project for mask submission, as explained in the “Complete a mask authorization form” section above.
  4. Enter the information for the layer(s) to be printed in the Layer [N] details section. Of particular importance is the polarity (inverted/non-inverted) and orientation (RRCU/RRCD). You can add additional layers to be printed (each layer represents a physical mask) by pressing the Add Layer button and entering the corresponding data for that layer.
  5. When finished, click Submit Request. You will receive a confirmation email.

You can monitor the status of the fabrication online (Photomasks → Queue) and you will also receive email notifications as your mask moves through the process (Submitted → Compiled → Exposing → Printed → Done). Please note that a status of “Printed” only means that the exposure step has been completed: developing, Cr etching, and resist stripping steps still remain. The mask is not ready for pick-up/shipping until its status is “Done”.

Additional Reading

Fabrication policy

  • All photomask fabrication requests must be submitted via LMACS.
  • Multi-layer submissions must use the same GDSII file. Each layer represents one physical mask.
  • Due to inherent differences in various CAD program outputs, mask results may vary.
  • The minimum feature size is 1 µm (exposed with the 4 mm lens); however, features below 2 µm may show distortions or fail to render.
  • Turnaround times may vary due to staff resources and equipment availability; however, the turnaround time under normal circumstances is approximately 10 business days.
  • Software support is provided on-site using the current version of L-Edit available in the nanoFAB design environment. The nanoFAB is not responsible for the integrity or compatibility of designs produced off-site, or with other versions of L-Edit.
  • Only the GDSII file format is accepted.
  • Submitted GDSII files will be stored for 1 year from the date of submission.
  • Masks with Problem status will be held in the queue for a maximum of 5 days, after which they will be deleted. Any warnings generated will be treated as a problem.
  • If there is a problem with one layer of a multi-layer mask set, all layers must be resubmitted.
  • All status updates are sent automatically via email. It is the user’s responsibility to ensure that the nanoFAB has the correct email address on file. Users can manage their contact info online.

Pricing & shipping policy

The following terms and conditions are enacted as the nanoFAB optical mask pricing and international shipping policy. This policy covers administration and pricing of optical masks to ensure consistent mask production to users and simplified administrative overhead; all prices listed below are in CAD.

  1. The pricing for photomask fabrication depends on the mask size, the lens used for exposure, and whether the customer is academic (affiliated with a Canadian educational institution), or external (not affiliated with a Canadian educational institution, such as industrial users or international academic users), as given by the project type for billing. The pricing does not depend on the device density or overall exposed area on the photomask.
    Mask size Lens Academic External
    5″ × 5″ 10 mm $185 $278
    7″ × 7″ 10 mm $370 $556
    5″ × 5″ 4 mm $379 $570
    7″ × 7″ 4 mm $758 $1140
  2. Shipping charges are applied directly to users with Freight on Board to the University of Alberta shipping dock. Users requiring shipping must submit a Courier Account Number during the online submission process. Masks requiring shipment without a Courier Account Number will be invoiced $150 for shipping (within Canada).
  3. A $25 handling surcharge will be applied to masks requiring shipping. This fee covers the cost of packaging and administrative overhead.

Optical mask pricing and shipping policy will be reviewed on a yearly basis for implementation on Sept 1.


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