https://nanyte.com/photoresists/k-pro · last updated 2026-08-04
- Manufacturer
- KemLab, Inc.
- Grades
- K-PRO 1 · K-PRO 2 · K-PRO 3 · K-PRO 5 · K-PRO 7 · K-PRO 151
- Tone
- positive
- Thickness
- 1–25 µm
- Developer
- 0.26N TMAH
- Applications
- Electroplating / molding · Etch mask · High aspect ratio
- Substrate
- Resist
- Exposed
Spin coating
For the K-PRO series spin curve, work from the manufacturer's datasheet and characterize film thickness on your own coater.
- Adhesion
- HMDS recommended — HMDS primer is recommended with oxide-forming substrates such as silicon (TDS p.2, Substrate Preparation); K-PRO adheres to silicon, copper, gold, glass, aluminum and chromium, and the datasheet claims excellent substrate adhesion for wet-etch work.
- Rehydration
- 3-30 minutes at 35-50% relative humidity, scaling with film thickness (TDS p.2, Rehydration Time).
Soft bake
- Soft bake
- 115 °C · 2–5 min · hotplate
- Notes
- Narrative Softbake section (p.2): 'Recommended softbake contact hotplate temperature is 115°C. Typical bake time is 2 – 5 minutes.' No single typical time is named, so the published 2-5 min window is recorded rather than a scalar.
SOURCE: Softbake section, p.2, and Processing Guidelines table, p.1, of the K-PRO TDS Rev 3-2021.
Exposure dose
K-PRO series's dose is published against film thickness, not as a single number. Read the row for the film you coat and run a dose array around it.
- As published
- Broadband aligner dose climbs steeply with the coat — 65 mJ/cm² at 1 µm, 125 at 7 µm, 380 at 25 µm.
| Film thickness | Dose |
|---|---|
| 1 µm | 65 mJ/cm² |
| 2 µm | 72 mJ/cm² |
| 3 µm | 76 mJ/cm² |
| 4 µm | 80 mJ/cm² |
| 7 µm | 125 mJ/cm² |
| 15 µm | 210 mJ/cm² |
| 25 µm | 380 mJ/cm² |
SOURCE: 'Broadband Aligner Exposure' column of the Processing Guidelines table, p.1 of the K-PRO TDS Rev 3-2021.
Development
- Developer
- 0.26N TMAH
- Developer family
- TMAH or buffered alkaline
Not published for this resist: Dilution, Time, Method, Rinse — characterize on-tool.
SOURCE: Development section, p.3, and the Features block, p.1, of the K-PRO TDS Rev 3-2021.
Hard bake, etch & strip
- Etch resistance
- Wet chemical etchants for Au, Cu, Cr and Al do not degrade patterns made with K-PRO (TDS p.3, Etch Resist).
- Stripper
- Industry-standard removers such as NMP at 50-80°C (TDS p.3, Resist Removal).
- Storage
- Store upright in an airtight container at 4-21°C, away from light, oxidizers, acids, bases and ignition sources (TDS p.3, Storage).
Not published for this resist: Hard bake, Descum — characterize on-tool.
Where it's used
Practical notes from the datasheet
K-PRO is KemLab's advanced-packaging positive series — six grades sharing one process family, aimed at plating, bumping, TSV and other metal-deposition work rather than at general lithography. Two things set it apart from a conventional thick positive resist. First, no post-exposure bake is required at all, which removes a step and its associated stress from the flow. Second, rehydration is an explicit, thickness-dependent process step (3 min at 1-3 µm rising to 30 min at 15-25 µm, at 35-50% RH) rather than an afterthought — skip it on the thick grades and development slows and scums. Broadband dose climbs steeply with the coat, from 65 mJ/cm² at 1 µm to 380 at 25 µm, so a dose array around the tabulated row for your film is the practical starting point. The grade numbers are product names, not thicknesses: K-PRO 5 is tabulated at 4 µm and K-PRO 15 covers both the 15 and 25 µm process points. Compatibility with copper, pure tin and nickel plating chemistries is claimed by the manufacturer, as is wet-etch resistance to Au, Cu, Cr and Al etchants; both are worth confirming against your own bath.
Sources & disclaimer
- KemLab, Inc. — K-PRO series datasheet (Rev 3-2021 (Copyright 2021 KemLab, Inc.; ISO 9001:2015 certified mark on every page)) · accessed 2026-08-04
- K-PRO TDS Rev 3-2021, 'PROCESSING GUIDELINES' table (p.1), Product column: K-PRO 1, K-PRO 2, K-PRO 3, K-PRO 5, K-PRO 7, K-PRO 15. The grade number does not track film thickness one-for-one — K-PRO 5 is tabulated at 4 µm, and K-PRO 15 carries two rows (15 µm and 25 µm) — so the numbers are product names, not thickness specifications.
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 2026-08-04.