https://nanyte.com/photoresists/kl-ir · last updated 2026-09-28
- Manufacturer
- KemLab, Inc.
- Tone
- image reversal
- Chemistry
- DNQ-novolak
- Thickness
- 1.2–2.6 µm
- Exposure dose
- 120 mJ/cm² (broadband, image-reversal mode)
- Developer
- 0.26N TMAH
- Applications
- Image reversal · General prototyping
- Substrate
- Resist
- Exposed
Spin coating
Data points
| Series | rpm | µm |
|---|---|---|
| KL IR 15 | 1000 | 2.6 |
| 2000 | 1.8 | |
| 3000 | 1.4 | |
| 4000 | 1.3 | |
| 5000 | 1.1 |
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 captioned 'Spin Curve' (referenced in text as Figure 3), p.2 of KL IR 15 TDS. Single unambiguous curve — only one grade/SKU is plotted, no multi-curve legend to disambiguate. Axis range (1.00-2.80 µm, 0-6000 rpm) and curve shape are consistent with the stated 1.2-2.6 µm film-thickness range.
- Spin curve determined on 6-inch Si with static dispense of ~4 mL of KL IR 15 resist (TDS p.2, Coat).
- No spin ramp/accel profile or edge-bead-removal step is published.
- A closely related sibling SKU, KL IR LO 15 (lift-off variant, separate TDS, Rev 10-2023), publishes a similarly-shaped spin curve on the same axis scale but is a distinct product literature and was not used to source any value here.
- Adhesion
- HMDS recommended — HMDS primer is recommended with oxide-forming substrates (Si, etc.); KL IR adheres to silicon, copper, gold, glass, aluminum and chromium (TDS p.1, Substrate Preparation, in both the Negative and Positive Resist Mode tables).
Soft bake
- Soft bake
- 105 °C · 1.5 min · hotplate
- Notes
- Single softbake condition (105°C, 90 sec) is common to both positive-mode and negative-mode processing guidelines (TDS p.1-2).
SOURCE: Negative Resist Mode Processing Guidelines table, p.1, and…
Negative Resist Mode Processing Guidelines table, p.1, and Positive Resist Mode Processing Guidelines table, p.2 of KL IR 15 TDS
Exposure dose
The manufacturer publishes 120 mJ/cm² (broadband, image-reversal mode). Dose scales with film thickness and depends on your optics, so treat it as a starting point and run a dose array.
- As published
- In reversal (negative) mode the image exposure is 120 mJ/cm² broadband before the reversal bake; used as a straight positive resist the only published figure is an approximate 70 mJ/cm² on a 1.5 µm film.
- Reversal bake
- 130 °C · 2 min
- Flood exposure
- 150 mJ/cm²
Not published for this resist: Dose at 365 nm, Dose at 405 nm — characterize on-tool.
SOURCE: Negative Resist Mode Processing Guidelines, p.1: 'Exposure Broadband (120 mJ/cm2)'
Development
- Developer
- 0.26N TMAH
- Time
- 45–60 s
- Method
- puddle
- Developer family
- TMAH-based
Not published for this resist: Dilution, Rinse — characterize on-tool.
SOURCE: Negative Resist Mode Processing Guidelines table, p.1, and…
Negative Resist Mode Processing Guidelines table, p.1, and Positive Resist Mode Processing Guidelines table, p.2 of KL IR 15 TDS
Hard bake, etch & strip
- Stripper
- KL Photoresist Remover, or industry-standard removers such as NMP or DMSO-based strippers, at 50-80°C (TDS p.1 spec box; p.3 Resist Removal); thicker films may benefit from a two-bath process — first bath removes bulk resist, second bath cleans thoroughly.
- Storage
- Avoid light; store in an upright airtight container at 4-21°C, away from oxidizers, acids, bases and ignition sources (TDS p.3, Storage — the document's own wording says 'Keep developer away from oxidizers...', apparently a boilerplate carryover referring to the resist itself).
Not published for this resist: Hard bake, Descum, Etch resistance — characterize on-tool.
SOURCE: Negative Resist Mode Processing Guidelines table, p.1, and…
Negative Resist Mode Processing Guidelines table, p.1, and Positive Resist Mode Processing Guidelines table, p.2 of KL IR 15 TDS
Where it's used
Practical notes from the datasheet
KL IR 15 is a dual-tone image-reversal resist: exposed through a mask, it can be processed as either a positive resist (softbake -> exposure -> PEB at 115°C/60s -> develop -> optional 115°C/60s hardbake) or, via an added reversal bake and flood exposure, as a negative resist with the opposite tone (softbake -> exposure -> reversal bake at 130°C/120s -> flood exposure -> develop -> optional 130°C/60s hardbake). The reversal-bake temperature is explicitly called out by the manufacturer as the single most process-sensitive parameter (±1°C tolerance), while the flood exposure is explicitly non-critical over a 150-300 mJ/cm2 window — the opposite of the usual intuition that exposure dose is the sensitive knob. KemLab also sells a separate, distinct SKU, KL IR LO 15, whose own TDS (same Rev 10-2023 date) markets it specifically for lift-off-profile negative processing and states it 'can replace AZ 5214E'; the plain KL IR 15 datasheet used here makes no equivalent lift-off-profile claim. Negative mode is described as having 'excellent thermal stability' and being 'optimized for metallization processes.' The dnq-novolak chemistry entry is based on the classic DNQ image-reversal process (reversal bake + flood exposure) that both the KL IR 15 and the sibling KL IR LO 15 TDS describe.
Troubleshooting
Common failure modes for KL IR 15, 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.
KL IR 15 in negative mode gives different feature sizes from run to run — where do I look first?
The reversal bake. KemLab calls its temperature the most critical factor in the image-reversal process and says it must be held within ±1 °C of the 130 °C, 120 s guideline for a stable process. MicroChemicals' general note on DNQ image-reversal resists adds that this is hard to hold in a convection oven, so a hotplate is strongly preferred, and that thick, massive or poorly conducting substrates, or a gap to the plate, need their own bake tuning.
SOURCE: KL IR 15 Photoresist TDS (KemLab Inc., Rev 10-2023) — Negative…
KL IR 15 Photoresist TDS (KemLab Inc., Rev 10-2023) — Negative Resist Mode Processing Guidelines, p.1; Reversal Bake, p.2. MicroChemicals application note 'Image Reversal Resists and their Processing' (not a KemLab document) — Influence of Substrate and Equipment
Narrow spaces won't clear in negative-mode KL IR 15 — should I push the flood exposure harder?
Probably not. KemLab rates the flood as non-critical: 150 mJ/cm² broadband is the guideline and anything from 150 to 300 mJ/cm² has no major effect. MicroChemicals' image-reversal note points at the other two knobs: a first (masked) exposure that is too high scatters light into nominally dark areas and makes narrow spaces hard or impossible to develop, and a reversal bake that runs too hot or too long thermally destroys photoactive compound, so the flood-exposed resist then develops more slowly.
SOURCE: p.2. MicroChemicals application note
KL IR 15 Photoresist TDS (KemLab Inc., Rev 10-2023) — Flood Exposure, p.2. MicroChemicals application note 'Image Reversal Resists and their Processing' (not a KemLab document) — The first Exposure; Influence of Baking Parameters
How do I get more undercut from KL IR 15 for a metal lift-off?
Run it in negative mode, which KemLab describes as optimised for metallization, and tune the masked dose and the over-develop. MicroChemicals' note on DNQ image-reversal resists says a lower first-exposure dose leaves the substrate-near resist less converted and gives a stronger undercut, while a very high dose gives almost none; and that the undercut grows mainly after the film has cleared, with about 30 % over-development as a starting point. Keep the resist much thicker than the metal, and watch that narrow lines are not undercut free of the substrate.
SOURCE: p.1. MicroChemicals application note
KL IR 15 Photoresist TDS (KemLab Inc., Rev 10-2023) — Description, p.1. MicroChemicals application note 'Image Reversal Resists and their Processing' (not a KemLab document) — The first Exposure; Formation of the Undercut; Sufficient Resist Film Thickness
Crater-like defects show up in my KL IR 15 after the reversal bake — what causes them?
Nitrogen from the exposure. KL IR 15 runs the classic image-reversal process of a DNQ-novolak resist (reversal bake plus flood exposure), and MicroChemicals' image-reversal note explains that DNQ releases nitrogen during exposure; if it has not diffused out before the reversal bake softens the film, bubbles form and appear as craters after develop. Leave a delay between exposure and reversal bake — minutes for a 1–2 µm film, per that note.
SOURCE: MicroChemicals application note
MicroChemicals application note 'Image Reversal Resists and their Processing' (not a KemLab document) — Formation of Bubbles in the Resist Film
Can I use KL IR 15 as a plain positive resist, and does its 115 °C PEB reverse the image?
Yes to the first. KemLab's positive-mode sequence is softbake 105 °C 90 s, exposure, PEB 115 °C 60 s, then 45–60 s puddle in 0.26N TMAH, with no flood step; its positive-mode example uses about 70 mJ/cm² broadband on a 1.5 µm film, against 120 mJ/cm² for the negative-mode image exposure. MicroChemicals' image-reversal note states that without both the reversal bake and the flood exposure an image-reversal resist behaves as an ordinary positive resist.
SOURCE: KL IR 15 Photoresist TDS (KemLab Inc., Rev 10-2023) — Figures…
KL IR 15 Photoresist TDS (KemLab Inc., Rev 10-2023) — Figures 1–2 process boxes, p.1; Positive Resist Mode Processing Guidelines, p.2. MicroChemicals application note 'Image Reversal Resists and their Processing' (not a KemLab document) — Process Sequence
Sources & disclaimer
- KemLab, Inc. — KL IR 15 datasheet (Copyright 2023 © KemLab, Inc., Rev 10-2023) · accessed 2026-07-10
- https://www.kemlab.com/_files/ugd/5b8579_45ff748fc0894fa094a12c113747f6ef.pdf — KemLab's KL IR LO 15 (lift-off variant) TDS — a sibling product datasheet, not an SDS. It shows the same classic DNQ image-reversal process (reversal bake + flood exposure) as KL IR 15, the basis for classifying KL IR as dnq-novolak; its flood-exposure table value (200 mJ/cm2) disagrees with its own narrative text (150 mJ/cm2), noted under the flood exposure step above.
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.