| HS Code | 595460 |
| Product Name | Ruihong Electronics I-line Photoresist |
| Type | Positive photoresist |
| Exposure Wavelength | 365 nm |
| Resolution | 0.35 µm |
| Viscosity | 10 mPa·s |
| Solid Content | 28% |
| Sensitivity | 80 mJ/cm² |
| Contrast | 3.0 |
| Storage Temperature | 5-25 °C |
| Shelf Life | 6 months |
As an accredited I-line Photoresist Ruihong Electronics factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Packaged in light-proof sealed bottles under nitrogen, each 1-liter container of Ruihong Electronics I-line photoresist ensures purity and stability. |
| Container Loading (20′ FCL) | Twenty-foot FCL loading of I-line photoresist from Ruihong Electronics, securely packed in sealed containers for safe chemical transport. |
| Shipping | Ship I-line Photoresist (Ruihong Electronics) as a Class 3 flammable liquid in UN-approved, grounded containers. Keep sealed, upright, and away from heat, sparks, open flames, and UV light. Follow the current SDS for exact UN number, packing group, and labeling. Ensure emergency response documentation accompanies the shipment. |
| Storage | Store I-line Photoresist (Ruihong Electronics) in original, tightly sealed containers in a cool, dry, well-ventilated area away from direct sunlight, ultraviolet light, heat, and ignition sources. Maintain recommended temperatures (typically 15–25°C), avoid freezing, and keep separated from oxidizers. Monitor shelf life and storage duration to prevent degradation or contamination. |
| Shelf Life | Store in a cool, dark place. Typical shelf life is six months from manufacture date when container remains unopened. |
Across 0.5–0.35 µm CMOS logic and mixed-signal wafer fabs, the Ruihong Electronics I-line photoresist is applied as a positive-tone implant and gate masking layer where KrF capacity is either unavailable or cost-constrained. The as-supplied material is a PGMEA-based DNQ-novolak formulation with ready-to-use dynamic viscosity in the 10–20 cP range at 25 °C; dilution with PGMEA is not recommended because reducing solids below the as-shipped value depresses the contrast curve and widens CD dispersion across the wafer. The substrate is prepared with vapor HMDS at 100–120 °C for 60 s, followed by spin coating at 3,500–4,200 rpm to obtain a 1.0–1.2 µm film. Softbake on a contact hotplate at 90–100 °C for 60 s drives off residual solvent without inducing flow. Exposure is performed with a 0.54 NA i-line stepper at 365 nm; typical clearing doses range from 80–120 mJ/cm², followed by PEB at 110–115 °C for 60 s. Development in 2.38 wt% TMAH (0.26 N) for 60 s using a single puddle produces 0.35 µm dense lines with 0.05 µm CD uniformity after descum in 50 W O₂ plasma for 20 s. The final product is a patterned wafer with implant-blocking oxide or poly gate stacks for ASICs, power management ICs, or analog/mixed-signal controllers. Compliance is maintained under SEMI S2, ISO 14644-1:2015 Class 5 cleanroom, RoHS Directive 2011/65/EU, and REACH Regulation (EC) No 1907/2006. Storage below 25 °C and pre-drying at RH above 60% before coating are necessary because moisture uptake shifts the surface dissolution rate and causes CD shift if the delay between coat and exposure exceeds 4 h.
Advanced packaging lines that build copper pillars and Au bumps for flip-chip and wafer-level CSP use the Ruihong Electronics I-line photoresist at final thicknesses of 8–12 µm over sputtered Cu/Ti seed layers. The two-step dispense and spin profile consists of static dispense of 2–4 mL per 200 mm wafer, closed-bowl spread at 900–1,300 rpm for 10 s, then final spin at 2,500–3,000 rpm for 30 s. The as-received high-viscosity formulation may be blended with PGMEA at 5–10 wt% only when target thickness falls below 8 µm; if dilution is used, the blend must be refiltered through 0.2 µm PTFE and allowed to stand for 30 min to dissipate microfoam. Softbake at 110–115 °C for 180 s on a proximity-pin hotplate is required to avoid solvent burst and edge bead lifting. Exposure at 365 nm uses 300–500 mJ/cm²; PEB at 115–120 °C for 120 s stabilizes the latent image before development in 2.38 wt% TMAH with double puddle for 120 s total. The process target is top loss below 0.5 µm and sidewall angle of 85–89° before copper electroplating at 2–5 A/dm² in a CuSO₄/H₂SO₄ bath with pH below 1. Resist stripping after plating uses NMP-based stripper at 60–70 °C or aqueous alkaline stripper; oxygen ashing alone may leave CuO residues. The final product is 25–80 µm diameter copper pillar bumps with 40–80 µm pitch for flip-chip and fan-in wafer-level CSP. Compliance follows RoHS Directive 2011/65/EU and REACH Regulation (EC) No 1907/2006. Published Ruihong-specific lot data above 12 µm is limited; cracking can occur at thicknesses above 12 µm unless the film is split into two coats with an interim bake.
| Parameter | Front-end implant | Advanced packaging bump | MEMS etch mask |
|---|---|---|---|
| Film thickness | 1.0–1.2 µm | 8–12 µm | 4–6 µm |
| Dynamic viscosity | 10–20 cP | 400–900 cP | 150–300 cP |
| Softbake | 90–100 °C / 60 s | 110–115 °C / 180 s | 100–105 °C / 90 s |
| Exposure dose | 80–120 mJ/cm² | 300–500 mJ/cm² | 180–250 mJ/cm² |
| Developer | 2.38 wt% TMAH | 2.38 wt% TMAH | 2.38 wt% TMAH |
For sacrificial oxide release in bulk micromachined inertial sensors and bulk acoustic wave membrane transducers, the Ruihong Electronics I-line photoresist is used at 4–6 µm as an etch mask over thermal oxide or CVD oxide. The resist is dispensed dynamically at 1,500–2,500 rpm, followed by edge bead removal with PGMEA and softbake at 100–105 °C for 90 s. Exposure at 365 nm uses a dose of 180–250 mJ/cm²; development in 2.38 wt% TMAH for 90 s with a double puddle clears 4–6 µm features without forming scum at the oxide interface. A hard bake at 120–130 °C for 60–120 s is applied only after inspection because it increases etch resistance but reduces strip performance. In buffered HF at a 7:1 NH₄F:HF ratio and 25 °C, the patterned resist remains intact for 10–15 min, enabling oxide release of suspended structures. In SF₆/CF₄ plasma etching, etch selectivity to oxide is typically above 3:1 when the hard bake is used. The final products are capacitive accelerometers, pressure sensors, and BAW resonators with released membrane or proof-mass topologies. Compliance is maintained under RoHS Directive 2011/65/EU, REACH Regulation (EC) No 1907/2006, and ISO 14644-1:2015 Class 5. Hard bake above 140 °C is not advised because DNQ-novolak resist reflow causes linewidth collapse and sidewall rounding; thickness above 6 µm can crack during sacrificial release due to film stress.
In LED contact metallization on GaN-on-sapphire, the standard positive-tone DNQ-novolak response of the Ruihong Electronics I-line photoresist yields a sloped positive sidewall, not the re-entrant undercut needed for clean metal lift-off. Two process pathways are therefore used. Where the specific Ruihong grade is rated for image reversal, the resist is coated at 3–4 µm over GaN, softbaked at 100 °C for 90 s, exposed with the first mask dose at 40–60 mJ/cm², reversal-baked at 110–120 °C for 120 s to crosslink the exposed surface, flood-exposed at 200–300 mJ/cm², and developed in 2.38 wt% TMAH for 60–120 s; this yields a negative-tone profile with controlled undercut. Where the grade is not image-reversal-capable, a solvent soak in chlorobenzene at 25 °C for 5 min after exposure swells the resist surface and promotes undercut after standard development. No hard bake is applied before metal evaporation; the metallization stack is typically Ni/Au or Ti/Al/Pt/Au at 1–3 µm. Lift-off is performed in NMP-based stripper at 60–70 °C with ultrasonic agitation below 40 kHz to avoid damaging the GaN surface. The final product is an LED p-contact pattern for flip-chip or vertical LED die. Compliance follows RoHS Directive 2011/65/EU and REACH Regulation (EC) No 1907/2006. Operational boundaries include a maximum reversal bake of 125 °C because higher temperatures crosslink the entire film and prevent complete dissolution; residual resist on GaN after lift-off must be checked by SEM/EDX for carbon at detection limits below 5 at%.
On 150–200 mm power semiconductor lines manufacturing 600–1200 V MOSFET and IGBT devices, a double-coat process with the same I-line resist produces a 4–6 µm film to mask high-energy implants. The first coat targets 2–3 µm and is softbaked at 100–105 °C for 90 s; the second coat is spin-coated to the final thickness and softbaked at 100–110 °C for 120 s. Exposure is performed at 365 nm with a dose of 200–300 mJ/cm²; development in 2.38 wt% TMAH with dual puddle for 120 s clears the implant openings without lifting the first coat interface. Implant masking covers phosphorus, boron, and arsenic at energies between 60–300 keV and doses up to 1×1016 ions/cm². After implantation, resist removal uses heated SPM at 120–130 °C for 15–20 min followed by O₂ ashing at 1–2 Torr, because high-dose implant species can crosslink the resist surface and leave carbon-rich residues. The final products are power MOSFET and IGBT wafers with field oxide openings, termination rings, and source/drain implant regions. Compliance is maintained under SEMI S2, RoHS Directive 2011/65/EU, and REACH Regulation (EC) No 1907/2006. Doses above 1×1016 ions/cm² and implant energies above 300 keV require site-specific strip validation; the resist should not be used as the sole mask for long high-dose As implants where wafer temperature exceeds 150 °C.
For fan-out wafer-level packaging, the Ruihong Electronics I-line photoresist is used as an etch mask for opening benzocyclobutene or polyimide passivation over copper redistribution traces. The substrate is first dehydration-baked at 110 °C for 60 s and, where adhesion is marginal on BCB, a thin HMDS monolayer is applied; the resist is coated at 3–5 µm thickness to cover 5–15 µm topography without voiding. Softbake is 100–105 °C for 90 s on a proximity hotplate. Exposure at 365 nm uses 150–220 mJ/cm²; development in 2.38 wt% TMAH for 60–90 s opens vias and RDL channels down to 5/5 µm line/space. The remaining resist serves as the mask during CF₄/O₂ reactive ion etching of BCB or polyimide, with etch selectivity to the organic dielectric of 2:1 to 4:1 depending on RF power and gas ratio; a typical gas ratio is CF₄:O₂ = 10:1 at 100–150 W. After etching, the resist is stripped in heated NMP or proprietary alkaline stripper, and copper oxidation is removed with dilute H₂SO₄:DI water at 1:10 by volume for 10 s. The final product is a chip-first or chip-last FOWLP substrate with open passivation vias and Cu RDL for subsequent solder ball attach. Compliance follows RoHS Directive 2011/65/EU and REACH Regulation (EC) No 1907/2006. A critical operational limit is that the resist must be descummed in O₂ plasma for 20 s before BCB etching to prevent organic residue at the via base, and developer attack of the Cu surface can occur if develop time exceeds 90 s.
Competitive I-line Photoresist Ruihong Electronics prices that fit your budget—flexible terms and customized quotes for every order.
For samples, pricing, or more information, please contact us at +8615365186327 or mail to admin@ascent-chem.com.
We will respond to you as soon as possible.
Tel: +8615365186327
Email: admin@ascent-chem.com
Flexible payment, competitive price, premium service - Inquire now!
On 150 mm silicon wafers with 1.0 µm thermal silicon dioxide or sputtered Al-Si-Cu metallization, the Ruihong Electronics I-line photoresist is applied as a positive-tone DNQ-novolac layer for contact-to-interconnect patterning in device flows with design rules at or above 0.45 µm. The product is identified in supplier documentation as the RZJ-3900 series, with viscosity sub-grades such as RZJ-304/25 selected for nominal film thickness from 0.8 µm to 3.0 µm. A 1.2 µm film is obtained at 3,500 rpm spin speed on a track coater using dynamic dispense of 3.0 mL per 150 mm wafer. Film thickness is measured by spectroscopic reflectometry per SEMI MF1530. The standard imaging sequence includes HMDS vapor prime at 110 °C, soft bake at 100 °C for 90 s, exposure at 365 nm on a 0.54 NA i-line stepper with open-frame dose of 120–180 mJ/cm², post-exposure bake at 115 °C for 60 s, and double-puddle development in 2.38% tetramethylammonium hydroxide for 45–60 s. The dose range is constrained by sidewall angle and critical-dimension linearity at 0.45 µm, not by photospeed alone.
The resist is a diazonaphthoquinone-photoactive compound in a cresol-formaldehyde novolac matrix. In the unexposed film, the photoactive compound acts as a dissolution inhibitor; after exposure at 365 nm, Wolff rearrangement converts the diazonaphthoquinone to indene carboxylic acid, enabling aqueous-base dissolution in the exposed regions. The casting solvent is primarily propylene glycol monomethyl ether acetate with a minor ethyl lactate fraction. Solid content is 27.0–31.0 wt% by ASTM D2369. Kinematic viscosity for the 1.2 µm grade is 18.5–22.5 mm²/s at 25 °C by ASTM D445. The product is filtered through 0.1 µm membranes, and particle concentration above 0.1 µm is controlled to fewer than 10 particles/mL on certificate-of-analysis sampling.
Spin-coating behavior follows a thickness-versus-spin-speed relationship that is approximately inversely proportional to the square root of rotational speed. The film thickness window is most stable between 2,800 rpm and 4,000 rpm. Soft-bake at 100 °C for 90 s reduces residual casting solvent to below 5 wt%, preventing bubble formation during exposure while retaining sufficient photoactive compound mobility for post-exposure diffusion. Lot-to-lot viscosity drift of ±0.5 mm²/s can shift a 1.2 µm film thickness by approximately ±35 nm if spin speed is not trimmed. On a production track with exhaust imbalance, intermittent film thickness variation of ±8% has been observed due to nozzle-tip drying during idle periods; a dummy dispense and backside rinse before each cassette is therefore required.
| Property | Method | Representative value for RZJ-3900 series 1.2 µm viscosity sub-grade |
|---|---|---|
| Kinematic viscosity at 25 °C | ASTM D445 | 18.5–22.5 mm²/s |
| Solid content | ASTM D2369 | 27.0–31.0 wt% |
| Water content | Karl Fischer titration | <0.50 wt% |
| Particles ≥0.1 µm | Optical particle counter | <10 particles/mL |
| Metal impurities Na, K, Fe | ICP-MS | each <50 ppb |
| Film thickness at 3,500 rpm | SEMI MF1530 | 1.18–1.28 µm |
| Refractive index at 633 nm | Spectroscopic ellipsometry | 1.62–1.65 |
| Minimum dense-line resolution | Cross-section SEM | 0.45 µm |
| Open-frame exposure dose | Dose-matrix wafer | 120–180 mJ/cm² |
The production window for the Ruihong I-line resist is bounded by soft-bake temperature, exposure dose, and developer normality. Soft-bake temperatures above 105 °C accelerate thermal decomposition of the diazonaphthoquinone photoactive compound and reduce development rate; temperatures below 95 °C leave residual solvent, causing rounded profiles and increased dark loss. The acceptable soft-bake window is therefore 95–105 °C, with hot-plate uniformity better than ±0.5 °C across the plate surface. Exposure dose latitude at 0.45 µm dense lines is approximately ±10% of nominal dose before critical-dimension deviation exceeds 10%. Post-exposure bake at 115 °C for 60 s completes photoactive compound diffusion and reduces standing-wave sidewall ripple. The critical-dimension sensitivity to post-exposure bake temperature is 1–3 nm/°C, which is broader than typical 248 nm chemically amplified resist behavior.
Developer normality is held at 2.38% tetramethylammonium hydroxide. Deviation to 2.45% increases dark erosion and produces foot loss at the resist-substrate interface, while deviation to 2.35% leaves residual scum in 0.45 µm spaces. Developer temperature is controlled to 23 °C ± 0.5 °C by an inline heat exchanger. Double-puddle development of 45–60 s is adjusted to endpoint plus 10–20 s. Endpoint detection is performed on a monitor wafer with equivalent substrate reflectivity; aluminum substrates require recalibration because reflectance shifts the effective dose-to-clear.
On HMDS-primed silicon after hard bake at 120 °C for 30 min, tape adhesion per ASTM D3359 method B remains class 5B. On copper or Al-Si-Cu substrates, surface oxides produce interfacial footing; a conformal organic underlayer or dehydration bake at 110 °C in nitrogen is used before coating. Pre-drying is required at relative humidity above 60% because novolac absorbs water and shifts development rate. Amine-based adhesion promoters are incompatible with the exposed resist chemistry; residual amines neutralize the indene carboxylic acid at the surface and create insoluble interfacial scum.
After patterning, the resist is hard-baked at 120–130 °C for 60–90 s to densify the novolac matrix and reduce wet-etch penetration. Hard-bake temperatures above 135 °C induce thermal flow and pattern rounding in sub-micron features, so the thermal budget is limited to 135 °C for dense-line geometries. In aluminum interconnect etching using BCl₃/Cl₂ plasma, 1.2 µm resist thickness is sufficient for metal thickness up to 0.8 µm under normal overetch conditions. For silicon etch masking in SF₆/C₄F₈ plasma, the resist remains intact through a 2.0 µm silicon etch when selectivity is at least 3:1. Oxide etch resistance is sufficient for 40:1 buffered hydrofluoric acid immersion up to 10 min without lifting from HMDS-primed thermal oxide.
Compared with positive-tone g-line resists, the Ruihong I-line formulation reduces matrix absorbance at 365 nm by using lower-absorbance novolac and a more photobleachable diazonaphthoquinone loading, enabling linear sidewalls at 0.45 µm dense pitch without optical trimming. Compared with chemically amplified 248 nm deep-ultraviolet resists, the DNQ-novolac system does not use photogenerated acid and is therefore not subject to post-exposure delay drift in amine-contaminated ambient up to 10 ppb. The trade-off is resolution; the Ruihong I-line system is not qualified for half-pitch below 0.25 µm. Compared with thick-film epoxy resists used for MEMS, the RZJ-3900 series is optimized for 0.8–3.0 µm coatings and is removable by standard plasma ashing or commercial solvent strippers at 70 °C; it is not suitable for permanent dielectric structures.
Delay between coating and exposure should be held below 2 h in a humidity-controlled wafer storage environment. Post-coating delay in ambient relative humidity above 60% increases surface water uptake and changes the development-rate profile at the resist-air interface, producing linewidth growth. Delay between exposure and post-exposure bake should be held below 60 min in amine-filtered air; ammonia concentrations above 10 ppb can produce T-top profiles by neutralizing indene carboxylic acid in the exposed surface layer. In a coater-to-stepper transfer excursion of 6 h, final inspection critical dimension shifted +25 nm at 0.45 µm nominal. Published data for this specific configuration is limited, but the supplier application notes flag post-coating delay beyond 2 h for rework before exposure.
Incoming quality control verifies viscosity, water content, solids, particle count, and lithographic performance using a dose-to-clear matrix on thermal oxide monitor wafers. Retention samples are stored at 5–25 °C in sealed bottles; shelf life is 12 months from date of manufacture. Freezing or storage below 0 °C is prohibited because phase separation of the novolac matrix can occur. The compliance matrix below summarizes the applicable standards and certificate-of-analysis verification.
| Standard | Scope | Verification |
|---|---|---|
| RoHS 2 2011/65/EU | Restricted substances | Certified below maximum concentration values |
| REACH 1907/2006 | Substances of very high concern | Supplier declaration |
| SEMI C28 | Chemical purity and packaging | Lot certification |
| ISO 14644-1:2015 | Cleanroom classification | Class 5 filling |
| ASTM D445 | Kinematic viscosity | CoA value |
| ASTM D2369 | Volatile content | CoA value |
The resist is not formulated for sub-0.35 µm design rules, copper/low-k integration without an intermediate underlayer, or processes requiring negative-tone sidewall profiles. Users should qualify the material on device substrates because aluminum reflectivity and topography alter dose-to-size and depth-of-focus. Published data for this specific configuration is limited outside the supplier certificate of analysis.
