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. Advance preparation -- 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.
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 review your requirements, discuss any design considerations. 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. As a reminder, additional consultation time will be billed as additional staff support at $55/hr.
Terms and Conditions
Agreement [link pdf] part of quote to be signed and returned
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, fabrication executed by QNF staff is often significant "intellectual contribution".
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.
Payment
Payment processing will be managed through our billing system in NEMO. Please submit the NEMO Access Request Form to begin account setup.