QNF Soft Litho Fabrication Service

About

The QNF provides a fabrication service of soft lithography masters for the purposes of PDMS molding/casting and associated applications, such as microfluidic device prototyping and production. Each master is custom fabricated by our technical staff in the QNF cleanroom using SU-8 negative epoxy resist (e.g., HARE SQ) on a 4” silicon wafer.

This service was created to address a need communicated by our colleagues at Penn School of Medicine and the Children’s Hospital of Philadelphia, where the onboarding and training time of a new cleanroom user is often too significant an investment for a lab needing only a couple masters requiring minimal fabrication once every few years.

Services

Our standard master fabrication process includes single layer photolithography (one feature height, no alignment) with basic quality inspection and characterization. Standard feature sizes/standard parameters include:

• Feature widths/lengths larger than 20 μm (within +/- 10% target value)
• Feature heights/channel depths up to 100 μm (within +/- 20% target value)
• Aspect ratios of width to height up to 1:10

Other services may be requested but are subject to additional review. These include two-layer masters, design assistance, and process optimization -- such as for smaller feature sizes, thicker layer heights, tighter tolerances, and specialty alignment.

Pricing

	Fee (Academic Rate)
Master, Single Layer	$ 1060
Master, Two Layers	$ 3295
Staff Support	$ 55 / hour

The per-master price is based on a comprehensive review of the required materials, equipment, hours and reflects the true costs of cleanroom fabrication.

Design assistance as well as consultations outside of the initial 30-min meeting will be billed as staff support. Additional fabrication services, such as calibration tests, will be an additional fee quoted based on individual processing needs. All pricing and tool availability are subject to change over time.

Limitations

Although we strive to minimize fabrication issues, we cannot guarantee specific defect density thresholds, exact sidewall smoothness or angle, precise feature depth tolerances, nor suitability for any particular application.

If the demand of your lab surpasses what QNF staff can reasonably provide through this fabrication service (e.g. high volume of requests or more intensive process development), you will instead be provided the option to sign up as a standard QNF user to continue these projects. For more information about soft lithography masters and processing, see the associated wiki page.

Getting Started

1. Create your design!

Having a clear final design concept to minimize possible reworking of the design, which will incur extra staff charges. If you have any questions about the design, you may reach out to QNF staff about available assistance.

Design Considerations

• Ideal feature sizes
  • Height < 100μm -- limited by available resist material and associated processing
  • Width > 10um, spacing > 10μm -- limited by photolithography process on thicker resist
  • Aspect ratios < 10:1 -- tall narrow structures can have less stability and be more prone to breakage or delamination

• Leave enough space to cut out the PDMS!
  • Designs should be > 10mm from the edge of the substrate (if using a 4" wafer, everything should fit within a 90mm diameter circular area)
  • Individual devices should be spaced > 15mm apart

2. Fill out our request form.

Make sure to include your design files, specifications and other needs. Staff will review your design and requested parameters ahead of the consultation to help get a sense of the feasibility, expected costs, and if there is any other information needed.

Complete specifications:

• Feature sizes (minimum and typical)
• Channel depths and widths
• Critical dimensions with tolerances

Design file:

• GDS format is preferred
• DXF is acceptable for discussion purposes, but conversion to GDS for fabrication will incur staff charges at $55/hour

3. Initial consultation (30 min)

After reviewing your request, someone from our team will contact you to schedule a consultation. During this meeting our team will

1. Review your design for feasibility with our processes and capabilities
2. Discuss specifications and clarify any ambiguities or questions
3. Identify potential issues and suggest optimizations if needed
4. Provide guidance on design best practices for successful fabrication
5. Estimate timeline and confirm pricing for your specific project
6. Determine next steps: whether ready for quote and fabrication, needing design modifications (may incur $55/hour charges), or scheduling an additional consultation to finalize details

IMPORTANT: This 30-minute initial consultation is the one complimentary consultation included with your service. Any additional consultation time beyond the initial session will be billed at $55/hour. If the design changes between your initial contact and your consultation, you are not guaranteed to have adequate staff review time, resulting in an inefficient consultation. Coming prepared helps ensure you get maximum value from this included consultation.

Preparing for Consultation

Your initial consultation is a valuable 30-minute session with our staff! This is your opportunity to get complimentary design review and fabrication guidance. To make the most of this time:

• Know your critical specifications and tolerances
• Prepare specific questions about feasibility or design concerns

It would also be helpful to have

• Sketches or diagrams of your design
• Examples of similar devices you've used
• Information about your PDMS molding process
• Any previous fabrication attempts and their outcomes

4. Submit the NEMO Access Request Form

This is required to begin account setup for billing. Any questions can be directed to admin@nano.upenn.edu.

5. Sign and return quote

Staff will follow up with the official quote, which must be signed and returned before fabrication begins. By signing the quote, you accept the quoted cost as well as the included service agreement (a copy can be found under Terms and Conditions below)

Delivery Time

Fabrication begins only after receipt of signed quote and confirmation of active NEMO account for billing. Turnaround time varies based on tool availability and master complexity. A more detailed timeline can be provided upon request.

Making Changes

Any changes to the fabrication request will require additional charges or order cancellation. Once fabrication begins, any modification or cancellation of an order will result in charges for any processing already executed for the previous request.

Terms and Conditions

Service Agreement

[link pdf] part of quote to be signed and returned

Payment

Payment processing will be managed through our billing system in NEMO. Please submit the NEMO Access Request Form to begin account setup.

Publications Policy

If you publish on devices or work done using this service, please add an acknowledgement or line of text stating the following: A portion of this work was carried out in part at the Singh Center for Nanotechnology, which is supported by the NSF National Nanotechnology Coordinated Infrastructure Program under grant NNCI-2025608. This is important for the continued success of our facility.

In addition, process knowledge gained from conversations, advice and brainstorming sessions, as well as fabrication executed by QNF staff may also constitute significant "intellectual contribution", and warrant authorship, or be worthy of an acknowledgement. Feel free to contact us if you would like to discuss, and thank you for understanding.