Biphoton SU-8 2000 Series Photoresist for High-Aspect-Ratio Microfabrication
| Brand | Biphoton |
|---|---|
| Origin | Shanghai, China |
| Manufacturer Type | Authorized Distributor |
| Product Category | Optical Instrument Component |
| Model | SU-8 2000 Series |
| Wavelength Sensitivity | Near UV (350–400 nm), compatible with i-line, electron beam, and X-ray lithography |
| Typical Film Thickness | 0.5–650 µm |
| Application Scope | MEMS, microfluidics, optical waveguides, passivation layers, and photonic device fabrication |
| Compliance | Compatible with standard semiconductor cleanroom processes (Class 100/10) and ISO 14644-1 certified environments |
Overview
The Biphoton SU-8 2000 Series is a high-performance, epoxy-based negative-tone photoresist engineered for precision microlithography in research and pilot-scale semiconductor, MEMS, and photonic device fabrication. Its crosslinking mechanism relies on cationic polymerization initiated by UV-generated acid catalysts—enabling exceptional resolution, thermal stability up to 200 °C, and near-zero outgassing during subsequent etch or deposition steps. Unlike conventional acrylic resists, SU-8 exhibits minimal shrinkage (<1.5%) post-exposure and post-bake, preserving critical feature fidelity in high-aspect-ratio structures (up to 20:1). The resist is formulated for compatibility with standard spin-coating equipment (100–6000 rpm), soft/hard bake ovens, and aqueous alkaline developers (e.g., 0.26 N TMAH), eliminating the need for hazardous organic solvents in development. Its optical transparency across visible and NIR wavelengths (400–1550 nm) supports integrated optical testing and alignment during multilayer processing.
Key Features
- High aspect ratio capability: Reliable patterning of features from sub-micron to >650 µm thickness with vertical sidewalls (wall angle ≥89.5°) and low line-edge roughness (<15 nm RMS)
- Thermal and chemical robustness: Withstands reactive ion etching (RIE) with SF6/O2, deep silicon etching (DRIE), sputtering, and electroplating without delamination or residue formation
- Low intrinsic stress: Compressive stress <50 MPa after full cure, minimizing substrate warpage—critical for wafer-level bonding and thin-film device integration
- Batch-to-batch consistency: Manufactured under ISO 9001-certified quality control; viscosity tolerance ±3% (measured at 25 °C per ASTM D1200)
- Extended shelf life: Stable for ≥12 months when stored at 2–8 °C in amber glass vials under inert atmosphere
Sample Compatibility & Compliance
SU-8 2000 demonstrates broad substrate adhesion across silicon (native oxide, thermally grown SiO2, HF-last), fused silica, quartz, glass (Corning 7740, Schott BF33), SOI wafers, GaAs, sapphire (C-, R-, M-plane), LiNbO3, and metalized surfaces (Ti, Cr, Ni, Au). Adhesion is enhanced via HMDS vapor priming or O2 plasma treatment (50–100 W, 30–60 s). The resist meets key industry requirements for process validation: it is compatible with GLP-compliant documentation workflows, supports audit-ready traceability (lot number, manufacturing date, QC certificate), and contains no restricted substances per RoHS Directive 2011/65/EU and REACH Annex XIV. While not classified as a medical device material, its residual metal content (<1 ppb Al, Fe, Na) satisfies SEMI F57 specifications for front-end semiconductor applications.
Software & Data Management
As a consumable photoresist, SU-8 2000 does not incorporate embedded firmware or software interfaces. However, its process parameters are fully integrable into industry-standard lithography data management systems—including KLA-Circon’s KLARF, Applied Materials’ Endura Data Suite, and open-source tools like LithoSim and Sentaurus Lithography. Process recipes (spin speed, soft bake ramp, exposure dose, post-exposure bake profile) can be exported in GDSII-compatible ASCII format for traceability. For regulatory environments requiring electronic records, usage logs may be captured via LIMS platforms compliant with FDA 21 CFR Part 11 (electronic signatures, audit trails, and data integrity controls).
Applications
SU-8 2000 serves as a foundational material in advanced microfabrication domains: structural layers in MEMS accelerometers and pressure sensors; microfluidic channel masters for PDMS replication; planar optical waveguides and grating couplers in integrated photonics; biocompatible electrode encapsulation in neural probes; and high-fidelity stencil masks for lift-off metallization. Its radiation stability enables use in synchrotron-based X-ray lithography (LIGA-like processes), while its electron-beam sensitivity supports maskless direct-write prototyping at ≤50 nm half-pitch. In academic and national lab settings, it is routinely employed in DOE-funded projects involving quantum photonic circuits, lab-on-chip diagnostics, and radiation-hardened sensor development.
FAQ
What is the recommended exposure dose for i-line stepper lithography?
Typical dose ranges from 15–45 mJ/cm² depending on film thickness, lens NA, and desired contrast—calibration via dose-to-clear experiments is advised.
Can SU-8 2000 be used on flexible substrates such as PI or PET?
Yes, with optimized adhesion promotion (e.g., oxygen plasma + silane coupling agents); however, thermal budget must remain below 150 °C to prevent substrate deformation.
Is residual stress measurement data available for this lot?
Stress values are reported in the Certificate of Analysis (CoA) provided with each shipment; wafer-level curvature measurements follow ASTM F390 methodology.
Does the resist require special handling under yellow-light conditions?
While SU-8 is not highly photosensitive pre-bake, handling under <500 lux yellow light (λ > 450 nm) is recommended to prevent ambient UV-induced premature crosslinking.
How does SU-8 2000 compare to SU-8 3000 in terms of adhesion and internal stress?
SU-8 3000 incorporates modified oligomer architecture yielding ~20% lower interfacial stress and improved adhesion to low-energy surfaces (e.g., bare Si, Al); SU-8 2000 offers superior resolution at sub-5 µm thicknesses and faster development kinetics.
