| HS Code | 697013 |
| Product Name | I-line Photoresist |
| Type | Positive photoresist |
| Sensitivity Wavelength | 365 nm (i-line) |
| Main Components | Novolac resin and diazonaphthoquinone (DNQ) photoactive compound |
| Resolution | Sub-micron, typically 0.35-0.5 µm |
| Contrast | High contrast, gamma > 2 |
| Typical Film Thickness | 0.5-2.0 µm |
| Developer Compatibility | Aqueous alkaline developers, e.g., TMAH 2.38% |
| Etch Resistance | Good resistance to wet and dry etch processes |
| Exposure Dose | Approximately 100-300 mJ/cm² |
| Thermal Stability | Stable up to post-bake temperatures of 110-130°C |
| Storage Shelf Life | 6-12 months under controlled, dark, cool conditions |
As an accredited I-line Photoresist factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | I-line Photoresist is supplied in sealed amber HDPE bottles, 1 quart (946 mL) per bottle, with nitrogen blanketing. |
| Container Loading (20′ FCL) | 20′ FCL: I-line photoresist packed in sealed containers, secured upright, temperature-controlled, protected from light and incompatible materials. |
| Shipping | I-line photoresist is a light-sensitive chemical requiring careful handling. Ship in opaque, tightly sealed containers to prevent UV exposure and leakage. Comply with hazardous material regulations, using appropriate labels and documentation. Avoid extreme temperatures and incompatible materials. Include Safety Data Sheets to ensure safe transport and handling throughout delivery. |
| Storage | Store I-line photoresist in its original tightly sealed container, away from light, heat, and ignition sources. Keep in a cool, dry, well-ventilated area at a recommended temperature, typically 15–25°C. Avoid UV exposure, as it causes degradation. Monitor expiration dates and follow manufacturer guidelines to maintain product performance and safety. |
| Shelf Life | Shelf life is typically 6–12 months when stored unopened in a cool, dark environment at controlled temperature. |
I-line photoresist operating at 365 nm is a positive-tone novolac/diazonaphthoquinone (DNQ) material system. Exposure converts DNQ via Wolff rearrangement to indene carboxylic acid; development in aqueous 0.262 N tetramethylammonium hydroxide (2.38 wt% TMAH) removes exposed areas while unexposed novolac remains insoluble. The downstream scenarios below are restricted to established manufacturing sectors in which i-line exposure, DNQ-novolac chemistry, and 2.38 wt% TMAH development are routinely qualified.
| Scenario | Novolac resin (wt%) | DNQ PAC (wt%) | Additive package (wt%) | Solvent system |
|---|---|---|---|---|
| CMOS implant/non-critical | 20–23 | 6–8 | <0.4 | PGMEA balance |
| Wafer-level bumping thick mask | 28–32 | 8–10 | 0.3–0.6 | PGMEA/PGME balance |
| MEMS hard-mask | 24–27 | 7–9 | <0.5 | PGMEA/cyclopentanone balance |
| LED lift-off / mesa | 18–22 | 5–7 | 0.1–0.3 | PGMEA/PGME balance |
| Display TFT array | 16–18 | 4–6 | 0.05–0.2 | PGMEA/PGME balance |
| IC substrate mSAP | 21–25 | 6–9 | 0.2–0.5 | DPM acetate balance |
For sub-20 nm CMOS logic and advanced DRAM/NAND production, i-line photoresist remains qualified on non-critical front-end layers such as implant masks, pad openings, and scribe line structures where feature sizes remain above 0.35 µm. The wafer is typically processed on 300 mm silicon through coater/developer tracks such as TEL ACT12 or DNS RF3i; after hexamethyldisilazane vapor prime at 110–130 °C for 60–120 s, dispense volume of 2.0–3.5 mL is spin-coated at 1200–2200 rpm to produce a soft-baked film thickness of 1.0–2.5 µm. Soft bake is held at 90–110 °C for 60–120 s; temperatures above 115 °C produce measurable DNQ thermal decomposition and photospeed loss, while temperatures below 85 °C leave residual casting solvent that generates post-exposure scum. Storage and dispense are maintained at 4–10 °C for resist bottles; dispense lines are held at 21–24 °C with point-of-use filtration at 0.1 µm to reduce particle defects. Exposure on i-line steppers with numerical aperture 0.48–0.63 uses doses of 80–180 mJ/cm². Development in 0.262 N TMAH (2.38 wt%) is carried out as a single or double puddle. Formulation addition ranges are novolac resin 20–23 wt%, substituted DNQ PAC 6–8 wt%, PGMEA-dominated solvent balance to 100 wt%, and surfactant/adhesion-promoting additives below 0.4 wt%. Industry compliance anchors include ISO 14644-1:2015 ISO Class 4 cleanroom control; SEMI S2-1122 for track and stepper operational safety; REACH Regulation (EC) No 1907/2006 for solvent and PAC substance registration; and RoHS Directive 2011/65/EU for packaged semiconductor devices where applicable. Terminal product types from these layers include CMOS logic chips, DRAM, NAND flash, and analog/mixed-signal wafers.
Within advanced wafer-level packaging lines, high-viscosity i-line photoresist is used as a thick plating mask for copper pillar, gold bump, and solder bump formation where single-coat thickness must reach 5–25 µm and the resist sidewall angle after development must remain 85–90°. The coating procedure on 200 mm or 300 mm bumped wafers typically uses a multi-step spin profile with initial spread at 150–300 rpm for 3–8 s, followed by high-speed spin at 400–1200 rpm to set film thickness. Soft-bake conditions are 100–120 °C for 180–300 s in proximity or convection ovens; excessive soft-bake above 125 °C suppresses development rate and increases interfacial scum. Because the thick film and high novolac loading absorb heavily at 365 nm, exposure dose requirements are 400–1200 mJ/cm². Published process windows for thick-film DNQ resists commonly define a minimum dose to clear of 300–500 mJ/cm²; above 1000 mJ/cm², residue risk after strip increases. Development is usually a double-puddle process using 2.38 wt% TMAH with total dwell time of 120–240 s, followed by deionized water rinse and spin-dry. The formulation addition envelope for these plating resists is novolac resin 28–32 wt%, DNQ PAC 8–10 wt%, PGMEA/PGME solvent balance, and low-foaming surfactant/adhesion promoters 0.3–0.6 wt%. Published data for this specific configuration is limited to supplier datasheet ranges because rework behavior depends on electroplating chemistry and seed-metal roughness. Relevant compliance standards include JEDEC J-STD-020E for moisture sensitivity classification, JEDEC JESD22-A113F for preconditioning before reliability testing, ASTM D3359-17 Method B for cross-cut adhesion verification on copper seed metal, and SEMI S2-1122 for coater/developer safety. Terminal product types include fan-in WLCSP, copper pillar flip-chip packages, gold bump wafer services, and high-density redistribution layers.
MEMS fabrication stacks that combine deep reactive ion etching (DRIE) with sacrificial oxide release require i-line resist that can withstand high-ion-flux etch environments while still being cleanly stripped after silicon trench formation. In these flows, the resist is dispensed onto 150 mm or 200 mm SOI or bulk silicon wafers after hexamethyldisilazane vapor prime; film thickness is typically 2–10 µm depending on desired DRIE sidewall passivation and trench depth. The coating process uses spin speeds of 800–2000 rpm, followed by soft-bake at 95–110 °C for 90–180 s. Pattern transfer is by i-line stepper or mask aligner with exposure doses of 100–250 mJ/cm². Development in 2.38 wt% TMAH is controlled to minimize swelling of unexposed novolac; post-development descum uses O2 plasma at 50–100 W for 30–60 s to remove interfacial residue. Amine-based contamination from wafer boxes or developer carryover causes dark film loss and must be excluded from the lithography environment. For Bosch-process DRIE, selectivity of silicon to this photoresist is commonly reported in the range 70:1–150:1 depending on chamber passivation parameters and aspect ratio. Formulation addition ratios for MEMS-grade i-line resists are novolac resin 24–27 wt%, DNQ PAC 7–9 wt%, PGMEA/cyclopentanone solvent balance, and thermal stabilizer packages below 0.5 wt%. Industry compliance standards include ISO 14644-1:2015 ISO Class 5 for MEMS cleanroom operations, SEMI S2-1122 for wafer-level process equipment safety, AEC-Q100-Rev-H for automotive MEMS device qualification where applicable, and ISO 13485:2016 for medical MEMS components that require documented cleanroom and material traceability. Terminal product types include inertial measurement units, MEMS microphones, pressure sensors, micromirrors, and bioMEMS microfluidic chips.
Gallium nitride LED mesa isolation and lift-off workflows employ i-line photoresist as a temporary mask for plasma etching, metal evaporation, and dielectric patterning on sapphire, SiC, or silicon substrates. On 2-inch and 4-inch LED wafers, the resist film is spin-coated at 1500–3000 rpm to produce thicknesses of 1.0–2.0 µm, with edge bead removal on the substrate periphery to enable uniform vacuum contact during exposure. Soft-bake is performed at 95–105 °C for 60–90 s; exposure is carried out on broadband or i-line mask aligners with dose of 80–180 mJ/cm². Development in 2.38 wt% TMAH generates the retrograded or undercut profile required for lift-off: the exposed DNQ area becomes soluble while the unexposed bulk remains insoluble, yielding an overhang after controlled over-development. In lift-off, the resist is typically undercut by 0.3–0.8 µm to create a discontinuous metal film after evaporation. Formulation addition ratios for LED lift-off resists are novolac resin 18–22 wt%, DNQ PAC 5–7 wt%, PGMEA/PGME solvent balance, and imidazole or silane adhesion promoter at 0.1–0.3 wt%. Relevant standards include SEMI S2-1122 for aligner and coater safety, ISO 14644-1:2015 ISO Class 5 for LED front-end cleanrooms, and EU RoHS Directive 2011/65/EU for finished optoelectronic components. Terminal product types include GaN-based LED chips, edge-emitting laser diodes, photodetectors, and vertical-cavity surface-emitting laser arrays.
On Gen 8.5 display substrates measuring 2200 mm × 2500 mm, slit-coating curtains and vacuum-dry ovens deposit i-line photoresist at film thicknesses of 1.5–2.0 µm for TFT array photolithography, where adhesion to sputtered molybdenum and aluminum gate lines and control of footing on tapered via edges determine final array yield. Large-area exposure with i-line steppers or proximity printers at 365 nm uses dose ranges of 50–150 mJ/cm²; after exposure, development in 2.38 wt% TMAH with multiple aqueous rinses removes exposed positive-tone resist and leaves feature resolutions of 1.5–3.0 µm for display backplane patterns. The low-solids formulation envelope for display-grade i-line resists is novolac resin 16–18 wt%, DNQ PAC 4–6 wt%, PGMEA/PGME solvent balance, and fluorosurfactant leveling agents at 0.05–0.2 wt% to suppress striation formation on large glass substrates. Relative humidity is maintained at 45±5% in the coating enclosure to reduce large-area drying non-uniformity. Process control requirements include coating uniformity better than ±3% across the panel and development endpoint detection to avoid over-etch of hydrogenated amorphous silicon or low-temperature polysilicon. Industry compliance standards include ISO 14644-1:2015 ISO Class 5 for display cleanrooms, SEMI S2-1122 for large-format coating and exposure equipment, and RoHS Directive 2011/65/EU for mercury-free display backlights in final products. Terminal product types include amorphous silicon TFT-LCD panels, indium gallium zinc oxide (IGZO) backplanes, low-temperature polysilicon AMOLED backplanes, and large-area sensor arrays.
When fine-line IC substrate patterning requires 5 µm line/space resolution on copper-clad laminates, i-line liquid photoresist is applied as an electroplating mask in modified semi-additive processes (mSAP) and advanced package substrate fabrication. The resist is roller-coated or spin-coated onto 0.2–1.0 mm dielectric substrates; film thickness after prebake is held at 5–12 µm depending on target copper plating height. Soft-bake is performed in stacked convection ovens at 80–100 °C for 20–40 min, followed by i-line exposure with dose levels from 200–600 mJ/cm² because copper-foil reflectivity and resist thickness increase required exposure latitude. Development in 1.0–2.0 wt% sodium carbonate or 0.4–0.6 N TMAH differs from wafer-grade TMAH formulations and is selected to minimize copper dissolution while clearing exposed resist. Development endpoint must be tightly controlled because sodium carbonate solutions above 2.0 wt% attack copper seed and induce undercut. Formulation addition ratios for substrate-grade i-line liquid resist are novolac resin 21–25 wt%, DNQ PAC 6–9 wt%, dipropylene glycol methyl ether acetate solvent balance, and epoxy adhesion promoters 0.2–0.5 wt%. Relevant compliance standards include IPC-4101E for base laminate requirements, IPC-6012E for qualification and performance specification of rigid printed boards, IPC-A-600K for acceptance criteria, and SEMI S2-1122 for wet processing equipment safety. Terminal product types include flip-chip chip-scale package substrates, mSAP high-density interconnect boards, and embedded die interconnect layers.
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The positive-tone I-line Photoresist product is formulated for 365 nm exposure in contact, proximity, and stepper lithography. The composition combines a cresol novolak resin matrix, a diazonaphthoquinone (DNQ) photoactive compound, and a propylene glycol monomethyl ether acetate (PGMEA) solvent system. Representative models include AZ 1512, AZ 1518, AZ 5214E for image reversal, and AZ P4620 for thick-film processing. Unexposed DNQ acts as a dissolution inhibitor for the novolak in aqueous base; absorption at 365 nm initiates a Wolff rearrangement to an indene carboxylic acid, increasing dissolution rate in 2.38 wt% tetramethylammonium hydroxide by 102–103. For AZ 1518, the datasheet kinematic viscosity is 30.5 mm²/s at 25 °C, film thickness after 4000 rpm for 30 s is approximately 1.8 µm, typical exposure dose is 100–150 mJ/cm², and line resolution is 0.5 µm on an i-line stepper with NA 0.50–0.60. Film thickness is measured by spectroscopic reflectometry or ellipsometry; rotational viscosity can be checked by Brookfield method following ASTM D2196.
Optical contrast γ for DNQ-novolak i-line resists typically falls between 2.5 and 4.0. Dark film loss in 2.38 wt% TMAH at 23 °C is usually below 10 nm/min. The refractive index at 365 nm is approximately 1.65, and absorbance is tuned to 0.60–0.80 µm⁻¹ to balance bleaching and sidewall angle. Adhesion on silicon, thermal oxide, and silicon nitride is achieved with hexamethyldisilazane (HMDS) vapour priming; cross-cut adhesion testing per ASTM D3359 on primed silicon can reach classification 5B after hard bake at 120 °C. Unprimed films may lift during developer rinse on silicon nitride and aluminium, particularly at feature sizes below 0.8 µm.
| Product model | Typical kinematic viscosity at 25 °C (mm²/s) | Typical film thickness after 30 s spin | Primary use |
|---|---|---|---|
| AZ 1512 | 11.5 | 0.6–1.2 µm at 3000–5000 rpm | Thin positive imaging |
| AZ 1518 | 30.5 | 1.5–2.2 µm at 2000–4000 rpm | Standard positive imaging |
| AZ 5214E | 28 | 1.2–1.8 µm at 3000–5000 rpm | Image reversal and lift-off |
| AZ P4620 | 130 | 6–12 µm at 1000–3000 rpm | Thick film and electroplating |
I-line DNQ-novolak resists do not contain a photoacid generator (PAG). The photoactive conversion is stoichiometric and does not involve acid-catalyzed deprotection. This gives lower sensitivity than KrF or ArF platforms but reduces post-exposure delay drift and airborne base sensitivity. Published comparative post-exposure delay data for specific product models remains limited; reported production data for 200 mm DNQ-novolak lines show that wafers can be held for 2 h at 45 ± 5% RH with linewidth change typically below 3 nm at a 0.5 µm nominal critical dimension. By contrast, chemically amplified DUV resists may show linewidth loss above 10 nm when post-exposure delay extends from 30 min to 120 min in uncontrolled amine environments. The i-line platform also operates at lower photon energy than 193 nm, which reduces outgassing and vacuum-related contamination in certain lithography tracks.
| Resist platform | Exposure wavelength (nm) | Imaging chemistry | Typical dose (mJ/cm²) | Typical resolution (µm) | Post-exposure delay sensitivity |
|---|---|---|---|---|---|
| I-line DNQ-novolak | 365 | DNQ/novolak | 100–150 | 0.35–0.50 | Low |
| G-line DNQ-novolak | 436 | DNQ/novolak | 80–120 | 0.80–1.0 | Low |
| KrF chemically amplified | 248 | PAG + polyhydroxystyrene | 20–50 | 0.15–0.25 | High |
| ArF chemically amplified | 193 | PAG + methacrylate | 20–40 | 0.065–0.090 | High |
On a coater-developer track, the i-line resist is dispensed through a 0.1 µm point-of-use filter at 1.5–3.0 mL for a 200 mm substrate. Spin speed is ramped at 5000 rpm/s to a final speed of 1500–4000 rpm; final spin time is 30–40 s. Soft bake on a proximity hotplate at 100–110 °C for 60–90 s reduces PGMEA to below 1 wt% residual solvent. Film thickness uniformity across 200 mm is controlled to ±2% (3σ) by spectroscopic ellipsometry using a Cauchy optical model. Exposure on an ASML PAS 5500/100 or Canon FPA-3000 i5+ i-line stepper uses NA 0.55–0.60 and partial coherence σ 0.55–0.60. Exposure dose is defined by cell clearing, typically 100–150 mJ/cm² for a 1.0 µm film thickness. Post-exposure bake at 110–120 °C for 60 s completes ketene conversion and thermal relaxation of the photoactive compound. Development with 2.38 wt% TMAH at 23 ± 0.5 °C for 45–60 s in puddle mode produces vertical sidewalls. Hard bake at 120–130 °C for 30 min increases chemical resistance but can shrink linewidth by 0.05–0.10 µm through thermal flow. The coating environment is maintained to ISO 14644-1 Class 5; alkaline particle contamination equivalent to 1 ppb amine can produce localized development slowdown even in non-chemically amplified films.
Thermal analysis of novolak-DNQ films shows that unexposed glass transition temperature after soft bake is typically 70–90 °C, while hard-baked films can exceed 120 °C through partial crosslinking. The novolak molecular weight distribution is controlled in the range 8,000–20,000 g/mol with polydispersity index 3.0–5.0 by gel permeation chromatography. DNQ ester loading is typically 20–30 wt% of total solids. These parameters determine the dissolution contrast and thermal flow boundaries. If soft bake is reduced below 95 °C, residual PGMEA can lower exposure dose by 5–8% and increase footing. If hard bake exceeds 140 °C, novolak crosslinking can make wet stripping more difficult and may require longer solvent immersion or plasma descum.
After dehydration bake at 120 °C and HMDS vapour prime at 110–130 °C for 60 s, the resist functions as a wet-etch mask in buffered hydrofluoric acid, phosphoric acid at 120–160 °C, and aluminium etch chemistries. Adhesion after hard bake can be assessed by tape peel using ASTM D3359; on silicon, class 5B is achievable for film thickness below 3 µm. Etch resistance is thickness-dependent; in 6:1 buffered oxide etch at 25 °C, a 1.8 µm AZ 1518 film resists attack for at least 10 min, although published etch-rate data for this exact configuration is limited. For lift-off, image reversal with AZ 5214E uses an initial masked exposure, reversal bake at 115–125 °C, flood exposure, and development to create a re-entrant profile. The removed resist can then be lifted off in acetone or NMP after metal evaporation. Standard positive i-line processing is less suitable for lift-off unless an overexposure/underdevelopment or chlorobenzene swell process is used, because conventional development produces positive slopes.
For copper pillar, solder bump, and MEMS electroplating, thick i-line positive resists such as AZ P4620 and AZ 40 XT are used because they are removed after plating with solvent or aqueous alkaline strippers, whereas crosslinked SU-8 negative epoxy requires aggressive plasma or hot piranha removal. A single coat of AZ P4620 yields 6–12 µm film thickness at 1000–3000 rpm; multiple coats and controlled solvent diffusion can extend thickness beyond 50 µm. Aspect ratios of 5:1 to 10:1 are reported for electroplating moulds with vertical sidewalls. In nickel sulfamate or acid copper sulphate plating, the resist should be hard baked near 120 °C to avoid thermal flow. Prolonged exposure to plating solutions above 60 °C can cause adhesion loss on copper if the seed layer is not primed; published data for this specific configuration is limited, so electrical test vehicles typically require plating bath compatibility trials before release.
In LED lift-off and power device fabrication, the i-line resist is applied after metal sputtering and patterned as a sacrificial mask. Because the DNQ-novolak film does not contain acid species that corrode aluminium, it is compatible with aluminium interconnect processing. A 1.0–2.0 µm film serves as an implant mask for medium-dose implant steps up to 1×1015 ions/cm²; for implant energies above 200 keV, thicker AZ P4620 films or double coating is used to limit ion tail penetration into the substrate. In thick resist patterning, sidewall angle and resolution are affected by exposure focus depth and development puddle uniformity; published process windows for specific electroplating features remain application-specific and are typically verified on product test wafers.
