https://nanyte.com/photoresists/pmgi-sf-6 · last updated 2026-09-28
- Manufacturer
- MicroChem
- Tone
- Not photoimageable (underlayer)
- Chemistry
- Ancillary (not photoimageable)
- Thickness
- 0.2–0.4 µm
- Exposure dose
- Not exposed — dissolves in developer
- Developer
- 0.26N TMAH (no product named); 0.24N has some compatibility and metal-ion-bearing developers are not rated (selection guide, p.7).
- Applications
- Lift-off
Cross-checked — two independent extractions agree on the spin curve and the single-value figures.
- Substrate
- Underlayer
- Resist
- Exposed
Spin coating
Data points
| Series | rpm | µm |
|---|---|---|
| SF 6 | 1000 | 0.44 |
| 1500 | 0.34 | |
| 2000 | 0.27 | |
| 2500 | 0.23 | |
| 3000 | 0.21 | |
| 3500 | 0.19 | |
| 4000 | 0.18 |
Values are the manufacturer’s starting points, not a guarantee — characterize on your own tool. Series digitized from a published figure are approximate (±10 %).
read from figure — the cyan asterisk trace legended SF 6 on the 'Thickness vs. Spin Speed - PMGI SF Series Thin Films' chart, p.5, the highest of the five traces. Seven plotted markers at 500 rpm intervals; no numeric table accompanies the chart.
- The topmost trace on the SF thin-films chart, falling from 4,380 Å at 1000 rpm to 1,780 Å at 4000 rpm.
- It is the steepest of the five and never flattens completely, so speed remains a usable control across the whole range — unusual among the sub-micron grades on this sheet.
- Coating parameters are published for the product line rather than per grade: 5 ml dispensed dynamically over 3-5 s onto a 150 mm wafer at 300-500 rpm, 10,000 rpm/s acceleration to a 3,000 rpm terminal speed, 45 s spin, with EBR PG for edge-bead and whisker removal.
- Adhesion
- HMDS not required — "Primers such as HMDS (hexamethyldisilazane) are typically NOT required to promote adhesion with PMGI/LOR products when used as recommended." (Substrate preparation, p.2). Recommended substrate prep instead: solvent clean or dilute-acid rinse, followed by DI water rinse, then a dehydration bake at 200°C for 5 minutes on a contact hotplate or 30 minutes in a convection oven. LOR/PMGI is stated to have excellent adhesion to Si, NiFe, GaAs, InP and other III-V materials (p.1 Features list).
Soft bake
- Soft bake
- 160–210 °C · hotplate
- Notes
- The prebake dries the film and fixes its dissolution and undercut rate, and no grade-specific temperature or time is published. The recommended prebake range for the product line is 160-210 °C, hotplate preferred, and the datasheet notes some PMGI products may be baked as high as 280 °C — a headroom the SF grades in particular are built for. Prebake temperature has the greatest influence on undercut rate, with prebake time, developer choice, develop mode and especially develop time behind it. The published undercut-versus-bake curves (Figures 5a and 5b) are measured on LOR 10B, not on an SF grade.
SOURCE: Rev. D p.3: 'The recommended bake temperature range is 160°C –…
Rev. D p.3: 'The recommended bake temperature range is 160°C – 210°C'; 'Hot plates are the preferred tool for the prebake step.'
Exposure
PMGI SF6 is not photoimageable. It is not exposed at all — it is coated beneath an imaged top resist and undercut laterally during development. See the development step below.
Development
- Developer
- 0.26N TMAH (no product named); 0.24N has some compatibility and metal-ion-bearing developers are not rated (selection guide, p.7).
- Dilution
- The Product Selection Guide (p.7) marks 0.26N TMAH as recommended and 0.24N TMAH as having some compatibility for the SF category; metal-ion-bearing developers are not rated for SF. No single dilution is given as SF6's own.
- Developer family
- TMAH or buffered alkaline
Not published for this resist: Time, Method, Rinse — characterize on-tool.
SOURCE: Development Process section, p.4; Product Selection Guide ("Developer Compatibility" rows, "SF" column), p.7
Hard bake, etch & strip
- Stripper
- Kayaku Advanced Materials' Remover PG, or other NMP or DMSO based removers, remove the bi-layer resist stack. Removal rate of LOR/PMGI is dependent upon the soft-bake temperature of the LOR/PMGI product and remover bath temperature. As a baseline process, use Remover PG in two tanks: at 60°C for 30 minutes in the first tank followed by a rinse at 60°C in the second tank. Ultrasonic action will improve the resist removal efficiency. Actual removal times will vary depending upon prebake conditions, subsequent processing and resist patterns (Lift-Off Process, p.4).
- Storage
- "Store upright in original sealed containers in a dry area between 10-24 °C (50-76°F). Keep away from sources of ignition, light, heat, oxidants, acids and reducers. Do not use product after the expiration date (13 months from date of manufacture)." (Storage, p.8)
Not published for this resist: Hard bake, Descum, Etch resistance — characterize on-tool.
Where it's used
Practical notes from the datasheet
PMGI SF6 belongs to Kayaku's PMGI SF series (SF 2/3/4/5/6 thin films and SF 8/9/11/13 thick films, plus SFS), a polydimethylglutarimide-based ancillary layer that is never itself exposed for patterning: in the standard bi-layer lift-off flow it is coated and soft-baked first, then a conventional imaging resist is coated, exposed and developed on top, and the same develop step dissolves an undercut into the PMGI beneath the imaging-resist pattern. Prebake temperature shows the greatest influence on undercut rate, with prebake time, choice of developer, develop mode and particularly develop time also influential; this datasheet's own quantified bake-temperature-vs-undercut-rate curves (Figures 5a/5b) are published only for LOR 10B, not for SF6 — a matrix design varying prebake temperature and develop time is recommended instead for fine-tuning any given grade. HMDS priming is explicitly NOT required for PMGI/LOR adhesion, and the imaging resist can be applied directly over PMGI without barrier layers or a plasma descum step. Stripping uses Kayaku Advanced Materials' Remover PG, or another NMP- or DMSO-based remover (baseline two-tank 60°C/30 min process); actual removal rate depends on the layer's own soft-bake temperature and the remover bath temperature.
Troubleshooting
Common failure modes for PMGI SF6, answered from the manufacturer's datasheet and application notes. These are starting points — your substrate, tooling and environment shift the specifics, so calibrate on-tool.
Is PMGI SF6 exposed like a normal photoresist?
Not in the standard bi-layer flow. The datasheet says LOR and PMGI resists do not require an exposure step in the simple bi-layer lift-off process, and need no post-exposure bake. SF6 is coated and soft-baked first; the imaging resist is then coated, soft-baked and exposed on top, and one develop step clears the imaging resist and dissolves SF6 isotropically, leaving a re-entrant undercut under the resist edge.
SOURCE: Kayaku Advanced Materials, "LOR and PMGI Resists" technical…
Kayaku Advanced Materials, "LOR and PMGI Resists" technical data sheet, Rev. D (August 2023) — Figure 4 (Process Flow), p.2; Application and Processing the Patterning Resist Layer, p.3; Post Exposure Bake (PEB) Process, p.4
How do I control the undercut of PMGI SF6?
With the soft-bake. The datasheet says prebake temperature has the greatest influence on undercut rate, with prebake time, developer choice, develop mode and particularly develop time also influential. It recommends a hotplate bake at 160-210 °C (some PMGI products to 280 °C) and a matrix of prebake temperature against develop time. Nothing is plotted for SF6; the nearest data, SF11 in 0.26N TMAH, fall from about 15 nm/s dissolution at a 170 °C bake to about 4.5 nm/s at 200 °C. Characterize SF6 on-tool.
SOURCE: Kayaku Advanced Materials, "LOR and PMGI Resists" technical…
Kayaku Advanced Materials, "LOR and PMGI Resists" technical data sheet, Rev. D (August 2023) — Soft-Bake/Prebake Process, p.3; Figure 6, p.4
Which developer does PMGI SF6 use?
The selection guide recommends 0.26N TMAH for the SF products and rates 0.24N TMAH only as some compatibility; metal-ion-bearing developers are hatched out for SF, as for every product except LOR B. The only SF dissolution data, Figure 6 for SF11, were taken in 2.38 % TMAH (0.26N). No SF6 develop time, method or rinse is published: the LOR/PMGI and imaging-resist thicknesses together set the develop time, so set it on-tool.
SOURCE: Kayaku Advanced Materials, "LOR and PMGI Resists" technical…
Kayaku Advanced Materials, "LOR and PMGI Resists" technical data sheet, Rev. D (August 2023) — Development Process and Figure 6, p.4; Product Selection Guide (Developer Compatibility), p.7
Does PMGI SF6 need HMDS or a descum/barrier layer under the imaging resist?
No. The datasheet says primers such as HMDS are typically not required with LOR/PMGI used as recommended, and the imaging resist can be applied and prebaked directly over the PMGI without barrier layers or a plasma descum; there is no intermixing between the layers when they are baked properly. Recommended substrate prep is a solvent clean or dilute-acid rinse, a DI water rinse, then a dehydration bake at 200 °C (5 min on a contact hotplate or 30 min in a convection oven).
SOURCE: Kayaku Advanced Materials, "LOR and PMGI Resists" technical…
Kayaku Advanced Materials, "LOR and PMGI Resists" technical data sheet, Rev. D (August 2023) — Substrate Preparation, p.2; Application and Processing the Patterning Resist Layer, p.3
Sources & disclaimer
- MicroChem — PMGI SF6 datasheet (Rev. D, August 2023 (printed in the footer of every page)) · accessed 2026-09-10
- Cord et al.. Robust shadow-mask evaporation via lithographically controlled undercut. Journal of Vacuum Science & Technology B (2006). doi:10.1116/1.2375090The Dolan-bridge PMMA/PMGI undercut process for evaporated Josephson junctions; PMGI develops in aqueous base, enabling a controlled undercut independent of the PMMA imaging layer.
Manufacturer datasheet values are starting points; optimal parameters depend on your substrate, equipment and environment. Product names and trademarks belong to their respective owners. NANYTE is not affiliated with the manufacturers listed. Last updated 2026-09-28.