| HS Code | 177277 |
| Photosensitive Wavelength | 436 nm (g-line of mercury lamp) |
| Polymer Resin | Novolac resin |
| Photoactive Compound | Diazonaphthoquinone (DNQ) |
| Resist Type | Positive-tone photoresist |
| Typical Resolution | 0.5 to 1.0 µm |
| Sensitivity | Approximately 50 to 200 mJ/cm² |
| Contrast | High contrast (gamma > 2.0) |
| Solvent Composition | Propylene glycol methyl ether acetate (PGMEA) or ethyl lactate |
| Film Thickness Range | 0.5 to 2.5 µm |
| Developer Compatibility | Aqueous alkaline developer (e.g., 2.38% TMAH) |
As an accredited G-line Photoresist factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Packaged in 1 L amber glass bottles, sealed with chemical-resistant lids, labeled clearly, and stored upright to protect light-sensitive G-line photoresist. |
| Container Loading (20′ FCL) | G-line photoresist packed in sealed, upright containers into 20′ FCL, secured properly, protected from heat/light, with hazard labels visible. |
| Shipping | Ship G-line photoresist in opaque, sealed, grounded containers to prevent light exposure and static discharge. Use authorized hazardous-material packaging with correct labels, SDS, and documentation. Comply with IATA, IMDG, or ADR regulations, protect from heat and ignition sources, and indicate handling and emergency response information clearly. |
| Storage | Store G-line photoresist in its original, tightly sealed container in a cool, dry, well-ventilated area away from direct sunlight and UV radiation. Maintain temperatures between 15–25°C, keep away from heat, sparks, and open flames, and separate from oxidizing agents. Check expiry dates and avoid contamination when dispensing. |
| Shelf Life | "Shelf life is typically 6–12 months from manufacture when stored unopened in a cool, dark, dry environment." |
Positive DNQ-novolac G-line photoresist is used on 150 mm and 200 mm silicon wafer lines for ion implantation masking, non-critical etch transfer, and bond pad opening definition. The applicable design rule band is 0.8 µm to 3.0 µm. Below 0.8 µm, the resolution limit of 436 nm exposure with conventional contact or proximity tools becomes statistically unstable in production. The resist is coated on HMDS-vapor-primed wafers, exposed on g-line steppers or aligners, and developed in metal-ion-free aqueous TMAH.
As-supplied material for this segment is formulated at 28–30 wt% solids, with a novolac resin to diazonaphthoquinone ester mass ratio of 2.2:1.0. PGMEA solvent accounts for 68–70 wt%, and a fluorosurfactant is present at 0.05–0.10 wt%. Viscosity is 8.5–11.0 cSt at 25°C per ASTM D445-21. The formulation is diluted with PGMEA at 1:0.3 by weight when target film thickness falls below 1.0 µm.
An HMDS vapor prime cycle at 120°C for 60 s precedes spin coating. A spin program of 3200 rpm for 30 s yields a 1.2 µm dry film after softbake at 100°C for 90 s on a vacuum hotplate. Exposure at 436 nm with a g-line stepper requires 80 mJ/cm². Development in 2.38 wt% TMAH at 22°C for 60 s clears exposed areas; unexposed film loss during development is controlled below 50 nm when post-exposure delay is kept under 30 min. Hardbake at 120°C for 30 min is used before plasma etch or high-dose implant to improve dry etch resistance and outgas control.
On production coat-and-develop tracks, batch-to-batch viscosity variation of ±2% at 25°C can shift mean film thickness by 80 nm on 200 mm wafers. Spin speed is trimmed in 50 rpm steps per incoming lot to hold thickness within ±1.5% of specification measured by spectroscopic reflectometry. Compliance documentation includes RoHS 2011/65/EU, REACH Regulation (EC) No 1907/2006, and SEMI S2 equipment integration. Cleanroom operation is performed in ISO 14644-1 Class 5 conditions.
Terminal devices produced with this resist include analog mixed-signal controllers, power management integrated circuits, and non-critical gate masks for discrete low-voltage MOSFETs. The material is not specified for sub-0.5 µm front-end layers where chemically amplified i-line or DUV resists are required.
In wafer-level packaging, the G-line resist acts as an electroplating mold for copper pillars, solder bumps, and redistribution layer lines. The main process conflicts are sidewall angle control in thick films, swelling during aqueous alkaline development, and interfacial adhesion loss in acid copper electrolytes. These three factors limit the usable aspect ratio more often than raw exposure resolution.
For 20 µm mold application, as-supplied viscosity is 1200–1800 cSt at 25°C and solids content is 42–46 wt%. The solid fraction contains novolac resin at 55–65 wt% and DNQ ester at 25–35 wt%; PGMEA forms 50–58 wt% of the total formula. Surfactant concentration is 0.2–0.4 wt%. No alkali-metal-containing additives are present because electroplating baths are sensitive to sodium and potassium contamination.
After Ti/Cu seed layer sputtering and HMDS vapor prime at 110°C for 90 s, the resist is spin coated with a two-step program: 500 rpm for 10 s for dispense spreading, then 1000 rpm for 40 s to set 20 µm dry film. Edge bead removal uses PGMEA dispensed at 200 rpm and spin-off at 3500 rpm. Edge accumulation above 10 µm creates a mask contact gap and subsequent plating leakage at the wafer perimeter, a common failure mode on 300 mm lines.
Softbake is a multi-step hotplate sequence: 65°C for 2 min, 95°C for 2 min, and 115°C for 10 min. The ramp rate is limited to 2°C/s; ramp rates above 5°C/s generate solvent vapor bubbles at the resist-copper interface. Hotplate temperature drift above ±2°C changes residual solvent content and alters development rate by approximately 5% per step in thick films.
Pattern exposure at 436 nm in vacuum contact mode requires 600–900 mJ/cm² for 20 µm thickness, corresponding to 40–50 mJ/cm² per µm. A post-exposure bake at 110°C for 60 s reduces standing-wave sidewall roughness. Development uses two puddle steps with 2.38 wt% TMAH, each 180 s, followed by a 90 s DI water rinse. Prolonged contact with aqueous developer swells the resist and can expand feature widths by 0.5–1.0 µm before rinse; total development time is therefore treated as a critical parameter.
Copper electroplating in a fountain cell at 2–4 A/dm² and 25°C subjects the mold to pH 0.8–1.0 electrolyte for 60–120 min. Adhesion loss at the seed layer is a documented failure when softbake temperature is below 110°C or when HMDS prime is incomplete. The usable aspect ratio is 2.5:1–3.0:1; above 3:1, development clearing of scum at the mold bottom becomes inconsistent without raising TMAH concentration. Published data for this specific configuration is limited.
Terminal structures include copper pillar bumps, solder bump molds, and redistribution layer traces in fan-out wafer-level packages. Compliance documentation includes RoHS 2011/65/EU, REACH Regulation (EC) No 1907/2006, and SEMI S2. Final resist strip uses alkaline aqueous solution at 45°C followed by solvent or plasma descum as needed.
| Production configuration | Dry film thickness | Coating method | Softbake | Exposure dose at 436 nm | Development in 2.38 wt% TMAH | Hardbake |
|---|---|---|---|---|---|---|
| Semiconductor implant mask | 1.2 µm | Spin 3200 rpm 30 s | 100°C 90 s | 80 mJ/cm² | 60 s puddle | 120°C 30 min |
| Wafer-level copper pillar mold | 20 µm | Spin 500/1000 rpm | 65°C 2 min / 95°C 2 min / 115°C 10 min | 600–900 mJ/cm² | 2×180 s puddle | Not applied before plating |
| Lead frame chemical milling mask | 6–8 µm | Spray coat | 100°C 10 min oven | 150 mJ/cm² | 90 s spray | 140°C 40 min |
Microelectromechanical systems fabrication on 150 mm silicon-on-insulator wafers uses G-line positive DNQ-novolac resist as a sacrificial mold for nickel electroforming and as an etch mask for Bosch-process deep reactive ion etching. The material is selected because it remains strippable after sulfamate nickel plating and does not develop thermal cracks when all bake steps are kept at or below 120°C.
For 18–25 µm mold thicknesses, the supplied resist is used without dilution. Viscosity is 2500–3200 cSt at 25°C per ASTM D445-21, solids content is 48–50 wt%, and the novolac resin to DNQ ester mass ratio is 3.0:1.0. Dispense volume of 6–8 mL on a 150 mm wafer with spin speed 800 rpm for 30 s provides uniform coverage; spin acceleration is limited to 300 rpm/s to avoid radial striations.
Softbake is performed in two stages: 65°C for 4 min to remove solvent, then 110°C for 8 min on a vacuum hotplate. Exposure on a g-line mask aligner in vacuum contact mode uses 800–1200 mJ/cm² for 20 µm film; the dose is verified with a 436 nm radiometer after lamp warm-up. Development is a four-puddle sequence with 2.38 wt% TMAH at 20°C, each puddle 120 s, followed by 120 s DI water rinse. The first puddle is discarded to remove the surface skin layer. Descum with oxygen plasma at 50 W for 30 s clears residual organic film from the mold bottom before nickel electroforming.
Electroforming in a sulfamate nickel bath at 45°C and pH 4.0 deposits structures up to 15 µm. The resist mold must remain adhered to the seed layer for 2–4 h of plating; interfacial adhesion loss is prevented by HMDS vapor prime at 120°C and by avoiding softbake temperatures above 115°C. The same resist is used for silicon DRIE masks; selectivity to silicon in the Bosch process is typically above 50:1, but chamber-specific qualification is required because SF₆/O₂ ratios and platen power alter the erosion rate.
Adhesion is checked by cross-hatch tape pull per ASTM D3359-17. Compliance documentation includes REACH Regulation (EC) No 1907/2006 and RoHS 2011/65/EU; processing is performed under ISO 14644-1 Class 5 cleanliness. Terminal products include capacitive pressure sensors, accelerometer comb-drive structures, microfluidic channel masters, and inkjet actuator nozzle plates.
In gallium nitride and gallium arsenide device fabrication, the G-line resist serves as a mesa etch mask and as a lift-off template for transparent conductive layers. The process is constrained by resist erosion in chlorine-based plasma and by edge bead formation on hard sapphire wafers, which do not flatten under vacuum contact like silicon.
Typical viscosity is 18–25 cSt at 25°C and solids content is 31–33 wt%. The novolac resin to DNQ ester mass ratio is 2.5:1.0. PGMEA solvent with surfactant below 0.10 wt% keeps metal-ion contamination below LED qualification limits. The formulation contains no free metal ions, which is necessary for compound semiconductor contamination control.
After UV ozone surface treatment to improve wetting on sapphire, the resist is spin coated at 2500 rpm for 30 s to obtain 1.8–2.0 µm dry film. Softbake at 100°C for 90 s precedes exposure at 436 nm on a contact aligner with 120 mJ/cm². Post-exposure bake at 115°C for 60 s improves sidewall smoothness. Development in 2.38 wt% TMAH at 22°C for 90 s is followed by hardbake at 130°C for 30 min.
Hardbake is mandatory before inductively coupled plasma etching in Cl₂/BCl₃ chemistry. Resist erosion in GaN mesa etching is observed at approximately 0.8–1.0 times the GaN etch rate; mask thickness is therefore set at 1.5× the target mesa depth. Wet etch of indium tin oxide is also possible because the hardbaked film resists acidic ITO etchants; however, published data for this specific configuration is limited. For lift-off processing, evaporated transparent conductor layers are separated by ultrasonic lift-off in alkaline stripper at 50°C, and complete removal must be confirmed by scanning electron microscopy.
Edge bead removal with PGMEA at 500 rpm is recommended because sapphire wafers are thinner and less compliant than silicon, and edge beads can prevent full mask contact. Compliance documentation includes RoHS 2011/65/EU, REACH Regulation (EC) No 1907/2006, and SEMI S2. Terminal products include blue and green GaN LED chips, GaAs infrared LEDs, laser diode ridge masks, and photodetector active area masks.
Copper and copper alloy lead frame fabrication uses liquid G-line resist where dry film lamination cannot resolve below 80 µm pitch or where a thin 6–8 µm mask is required for chemical milling. The liquid resist also removes the dry film lamination temperature step, which is useful for thin copper substrates prone to warp.
Spray-coatable formulations are adjusted to 580–850 cSt at 25°C, with solids content 36–39 wt% and a novolac resin to DNQ ester mass ratio of 3.0:1.0. Dilution with PGMEA at 5–10 wt% is permitted to target 6 µm dry film on copper alloys.
Substrate cleaning uses sulfuric acid/hydrogen peroxide microetch followed by DI water rinse and nitrogen drying. Spray coating deposits a 6–8 µm film; softbake in a forced-air oven at 100°C for 10 min removes residual solvent. Exposure uses a collimated g-line source at 150 mJ/cm². Development by spray with 2.38 wt% TMAH at 20°C for 90 s clears the pattern. Hardbake at 140°C for 40 min is necessary before ferric chloride or cupric chloride spray etching at 45°C; under these conditions, the mask withstands 20–30 min of acid spray without lifting.
Developer spray pressure above 1.5 bar is avoided because impingement at the resist edge increases undercut by up to 2 µm per side. Adhesion on microetched copper is checked by cross-hatch tape pull per ASTM D3359-17. Compliance documentation includes RoHS 2011/65/EU and REACH Regulation (EC) No 1907/2006. After strip in alkaline aqueous solution at 45°C, the copper surface is inspected for organic residue by water break test and scanning electron microscopy. Terminal products include QFN lead frames, discrete transistor lead frames, intelligent power module lead frames, and battery tab masks.
Specialty display and sensor backplane photolithography on glass and flexible substrates uses G-line positive resists in contact and proximity aligners where design rules are 2.5 µm and above. The process is used on legacy TFT-LCD lines and on sensor arrays that do not require sub-2.5 µm gate patterning.
The resist is supplied at 12–20 cSt at 25°C, solids 28–30 wt%, and a novolac resin to DNQ ester ratio of 2.0:1.0. PGMEA solvent content allows slit die coating or spin coating on glass and foil substrates. Substrate cleaning by UV ozone precedes coating; a 1.0–2.0 µm dry film is softbaked at 90°C for 2 min.
Exposure at 436 nm in a proximity aligner uses 100–200 mJ/cm². Development in 2.38 wt% TMAH for 60 s is followed by hardbake at 120°C for 30 min before wet or dry etch of transparent conductor or metal layers. Thickness uniformity on large plates is held within ±3%; hotplate zoning is verified by spectroscopic reflectometry because solvent loss varies across the plate.
Compliance documentation includes REACH Regulation (EC) No 1907/2006 and RoHS 2011/65/EU. Terminal products include industrial TFT-LCD modules, X-ray sensor panels, and capacitive sensor backplanes.
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G-line Photoresist is a positive-tone, solvent-borne photoresist formulated for exposure at 436 nm, the mercury G-line. The formulation consists of a cresol-formaldehyde novolak resin and a diazonaphthoquinone photoactive compound dissolved in an electronic-grade solvent system based on propylene glycol monomethyl ether acetate (CAS 108-65-6) with an ethyl lactate (CAS 97-64-3) co-solvent. The product is supplied through a 0.1 µm polytetrafluoroethylene filter and is intended for spin coating, spray coating, and dip coating on silicon, silicon dioxide, silicon nitride, aluminum, and select III-V substrates. Unlike negative-tone bis-aryl azide resists, the DNQ-novolak system is aqueous-base developable, non-swelling during development, and does not require solvent development. The material is available in low-, mid-, and high-viscosity grades corresponding to nominal spin-coated film thicknesses from 0.5 µm to 2.5 µm at 2000–6000 rpm. Grade designation follows viscosity-stack format rather than a single model number; the mid-viscosity grade is specified for 1.0 µm to 1.8 µm films on production coat tracks.
Resolution for contact and proximity exposure is dominated by mask-to-resist gap, resist thickness, and the angular divergence of the arc lamp. In a proximity system with a 20 µm gap, diffraction blur is approximately 2.8 µm; in vacuum contact, 1.0–1.5 µm isolated features are commonly resolved if the film thickness is kept at or below 1.2 µm. Production aligners with 350 W Hg short-arc lamps and chromium-on-glass masks typically exhibit exposure latitude of approximately ±10% for 2.0 µm features. Exposure dose at 436 nm for a 1.0 µm film is normally in the 80–150 mJ/cm² range; the value shifts upward when softbake is extended beyond 120 s at 110 °C because residual solvent is depleted and the photoactive compound becomes more ordered.
Spin-coated thickness is controlled by fluid viscosity, solvent boiling point, exhaust flow, and wafer temperature. Representative process data for mid-viscosity G-line resist on 150 mm silicon wafers are summarized in Table 1.
| Property | Representative Range | Method or Reference |
|---|---|---|
| Viscosity at 25 °C | 5–50 mPa·s depending on grade; mid-viscosity 20–30 mPa·s | ASTM D2196-20 rotational viscometer |
| Non-volatile solids | 20–35 wt% after solvent removal at 105 °C | ASTM D2369-20 |
| Nominal film thickness | 0.6–2.0 µm at 2000–6000 rpm on 150 mm Si | spectroscopic reflectometry, 550 nm Cauchy model |
| Softbake | 90–110 °C on vacuum hotplate, 60–120 s | contact hotplate, ±2 °C surface uniformity |
| Dark erosion | 5–15 nm after 120 s immersion in 0.26 N TMAH | interferometric thickness loss |
| Contrast | 2.0–2.8 from normalized remaining thickness versus log dose | step-wedge exposure and reflectometry |
| Photosensitivity | 80–150 mJ/cm² at 436 nm | quartz mask step wedge |
Film thickness uniformity on 150 mm wafers is typically ±2% when the resist is dispensed as a 3 mL puddle over 3 s and spun with a closed-bowl exhaust of 50–80 m³/h. Edge bead removal is performed with PGMEA or ethyl lactate using a bottom-side rinse; if the edge bead is not removed before softbake, contact aligner soft-contact modes can transfer mask contamination to subsequent wafers.
The most direct comparison is with i-line photoresists. Both G-line and i-line products use DNQ-novolak chemistry, but G-line formulations are spectrally sensitized for 436 nm and therefore require a higher dose than an equivalent i-line film at 365 nm. Typical G-line photospeed is 1.5–2.0× slower because the mercury lamp output at 436 nm is high but the DNQ absorption is lower than at 365 nm. Thermal stability is comparable: a hardbake of 120–130 °C for 30 min is sufficient for buffered oxide etch and phosphoric acid metal etch; crosslinking and flow become significant above 140 °C. The absence of chemical amplification means there is no post-exposure bake acid-catalyzed deprotection step and no sensitivity to airborne amines. Compared with 248 nm and 193 nm chemically amplified resists, the G-line product has a wider film thickness range and better adhesion on polar substrates, but lower intrinsic resolution and lower plasma etch resistance. Under a CHF₃/CF₄ reactive-ion-etch process at 50 W, a dense novolak film may etch 1.2–1.8× faster than silicon dioxide, whereas selected polyhydroxystyrene systems can be tuned to ratios near 1.0×. Published data for exact etch rate ratios on specific equipment remain limited.
Differences from negative-tone solvent-developed resists are operationally significant. G-line positive resist does not swell during development, so linewidth loss in fine features is generally lower than with solvent-developed cyclized polyisoprene resists. The developer is aqueous, supplied as 2.38% tetramethylammonium hydroxide, which eliminates much of the solvent waste stream associated with xylene-based negative developers. The principal trade-off is coating conformality on severe topography, where negative resists have historically been preferred for electroplating molds because of their thicker crosslinked layer.
On pre-etched substrates, spin coating produces a non-conformal thickness profile: the rim of a 5 µm etched cavity may retain 20–40% less thickness than the field area, making linewidth control difficult at the step edge. Spray coating with a low-solids dilution of the same product is used to follow moderate topography, although coverage inside narrow trenches with aspect ratio above 2:1 remains incomplete. For pressure sensor and microfluidic mold fabrication, a two-coat process at 1500 rpm for the first coat and 4000 rpm for the second has been used to reduce edge thinning. Production records from 100 mm InP wafers indicate that the G-line DNQ-novolak film adheres to silicon nitride without HMDS but requires dehydration bake above 150 °C for 120 s before coating on gallium arsenide to minimize lifting during 0.26 N TMAH development.
A practical point for MEMS processing is that this resist is not suitable as a permanent structural material. Its glass transition and flow above 140 °C limit its use to sacrificial masking or short-term etch and electroplating steps. For electroplating masks in copper or nickel, a thicker film of 3.0–5.0 µm can be obtained with multiple coats, but the first coat must be softbaked fully to prevent solvent entrapment and blistering during subsequent coats. Published data for this specific configuration is limited; users typically validate adhesion by sequential immersion in acidic copper sulfate plating baths.
The standard developer is 0.26 N tetramethylammonium hydroxide at 21–23 °C. Development rate is strongly temperature-dependent: a temperature increase from 21 °C to 23 °C can reduce time-to-clear by 10–20% for DNQ-novolak films. Single-puddle development is preferred over spray development for dark erosion control, but puddle stagnation can leave residue at the base of dense line-space arrays. A 2.0 µm line-space pattern exposed on a contact aligner may require 45–90 s of puddle development with intermittent wafer rotation at 30–60 rpm to remove dissolved resist from the feature surface. Dynamic developer dispense with a 0.8 µm point-of-use filter reduces particulate defects; unfiltered developer can shed organic agglomerates that cause bridging in sub-2 µm features.
Plasma descum before development is not routinely required for G-line resist on HMDS-primed silicon, but a short O₂ descum of 30–60 s at 50 W in a barrel etcher removes a thin DNQ scum layer. On copper and gold surfaces, adhesion is inferior unless a thiol- or HMDS-based bilayer is applied. These metallic surfaces can also change the development residue profile; copper oxide may react with the developer to form a visible blue-green residue that must be removed by a dilute acetic acid rinse before inspection. Avoid combination with amine-based adhesion promoters and unpassivated metals that catalyze diazonaphthoquinone decomposition. The process window narrows when relative humidity exceeds 60% because the novolak film absorbs water, reducing photospeed and increasing residue. In such conditions, a dehydration bake of 110 °C for 120 s immediately before exposure is recommended.
Because this photoresist is solvent-borne and flammable, it must be handled in explosion-proof coating tracks with 30–60 L/min exhaust per spin bowl. The flash point of the PGMEA-based solvent system is approximately 42 °C; storage below 25 °C is recommended. The product is not intended for sub-micrometer advanced-node lithography, nor for exposure wavelengths below 300 nm where the novolak matrix absorbs strongly. Total sodium and potassium target specification is below 50 ppb each by inductively coupled plasma mass spectrometry, and the product meets RoHS Directive 2011/65/EU restrictions for lead, mercury, cadmium, hexavalent chromium, PBB, and PBDE. No heavy-metal additives are present in the formulation.
