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 covers all costs associated with 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 is subject to change
Getting Started
- Advance preparation -- create your design. You can refer to the good design considerations below. Having a clear final design concept to minimize possible reworking of the design, which will incur extra staff charges.
- 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.
- 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.
, and provide transparent pricing based on complexity, materials, and timeline.
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
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
If you have any questions about the design, you may reach out to QNF staff.