| HS Code | 756847 |
| Product Name | Stripper of Organic&Aqueous Systems Electronic/EL Grade |
| Chemical Type | Proprietary blend of organic solvents and aqueous alkaline components |
| Appearance | Clear, colorless to slightly yellow liquid |
| Specific Gravity 20c | 1.01 - 1.05 |
| Ph 25c | 8.5 - 10.5 |
| Flash Point | Greater than 60 degrees C (closed cup) |
| Boiling Point Range | 100 - 150 degrees C |
| Vapor Pressure 20c | Less than 0.1 kPa |
| Solubility In Water | Fully miscible |
| Purity Level | Electronic/EL grade, particulate filtered to 0.1 micrometers |
| Metal Ion Impurities | Less than or equal to 1 ppb each for Na, Fe, Cu, Zn, Al, Ca |
| Etch Selectivity | Negligible etch rate on SiO2, Si3N4, and metallic films |
| Rinseability | Excellent with deionized water and isopropyl alcohol |
As an accredited Stripper of Organic&Aqueous Systems Electronic/EL Grade factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Packaged in 1-gallon sealed HDPE containers, this EL-grade stripper for organic and aqueous systems ensures purity and safe handling. |
| Container Loading (20′ FCL) | 20′ FCL loaded with EL-grade organic/aqueous stripper in UN-approved containers, segregated, secured, and labeled for safe transport. |
| Shipping | Stripper of Organic & Aqueous Systems (Electronic/EL Grade) ships in sealed, contaminant-free HDPE containers with tamper-proof closures. Transport requires hazmat classification per UN/DOT/IMDG/IATA regulations, complete SDS documentation, and leak-proof secondary containment. Avoid extreme heat and UV exposure; handle with dedicated equipment and approved PPE during loading and unloading. |
| Storage | Store in a clean, tightly sealed original container in a cool, dry, well-ventilated area. Avoid direct sunlight, moisture, and extreme temperatures. Keep away from incompatible materials, including strong oxidizers and acids. Ensure proper labeling and segregation. Use chemical-resistant containment and follow EHS guidelines to prevent contamination and maintain electronic-grade purity. |
| Shelf Life | Shelf life is typically 6–12 months when stored tightly sealed in original containers, away from heat, light, and moisture. |
On copper/low-k backend-of-line wafers following fluorocarbon/oxygen reactive-ion via etch, the sidewall polymer contains titanium silicide, aluminum fluoride, and cross-linked fluoropolymer species that survive downstream oxygen ash. A bath containing 70–85 vol% electronic/EL grade stripper and 15–30 vol% deionized water is recirculated through 0.1 μm polytetrafluoroethylene filters to remove agglomerated polymer particles before they redeposit on damascene profiles. The chemistry is operated at 65–72 °C for 14–20 min in a quartz or perfluoroalkoxy immersion tank; single-wafer spray processors achieve comparable residue removal at 70–80 °C for 90–150 s if the spray nozzle array delivers 1.6–2.2 bar to the wafer surface. Copper corrosion is controlled by a heterocyclic inhibitor at 0.15–0.35 wt%; the resulting etch rate remains below 1 Å·min⁻¹ as measured by four-point probe sheet-resistance pre/post. Trace metal acceptance follows SEMI C35 cation limits of ≤10 ppb for sodium, potassium, calcium, magnesium, and iron, while anion contamination is held below 50 ppb measured by ion chromatography per ASTM D4327. Terminal output includes 7 nm node logic and 1x-nm DRAM wafers. The primary operational boundary is pH drift: a rise of more than 0.4 pH units from the fresh bath value increases aluminum fluoride attack at the tungsten plug interface; replenishment with solvent-rich concentrate at 8–12 vol% of bath volume per wafer lot maintains bath stability. Published data for cobalt-compatible stripper formulations at sub-10 nm nodes is limited.
| Parameter | Method | Limit |
|---|---|---|
| Sodium | ICP-MS per SEMI C35 | ≤10 ppb |
| Potassium | ICP-MS per SEMI C35 | ≤10 ppb |
| Calcium | ICP-MS per SEMI C35 | ≤10 ppb |
| Magnesium | ICP-MS per SEMI C35 | ≤10 ppb |
| Iron | ICP-MS per SEMI C35 | ≤10 ppb |
| Chloride | Ion chromatography per ASTM D4327 | ≤50 ppb |
| Sulfate | Ion chromatography per ASTM D4327 | ≤50 ppb |
| Particles ≥0.5 μm | Liquid particle count per SEMI C35 | ≤25 counts·mL⁻¹ |
Fan-out and copper pillar wafer-level packaging lines that strip 5–10 μm polyimide or 4.5 μm benzocyclobutene passivation after via plasma processing require a stripper that clears graphitized via-bottom residue without attacking Cu/Ni/Au under-bump metallurgy. The electronic/EL grade stripper is blended at 60–75 vol% active organic phase, 15–30 vol% aqueous alkanolamine, 1–3 vol% corrosion inhibitor, and the balance low-defect semiconductor-grade water. Process temperature is held at 70–78 °C for 10–20 min in a recirculated etch bath equipped with 40 kHz megasonic transducers; megasonic power density is set at 0.8–1.2 W·cm⁻² to avoid under-bump metallurgy delamination at the TiW/Cu interface. Under these conditions, TiW etch rate stays below 0.5 Å·min⁻¹, Cu below 1 Å·min⁻¹, and polyimide film thickness loss below 2% per pass. Bath life is governed by dissolved residue loading: when solids exceed 25 g·L⁻¹, polyimide residue redeposits as 0.2–1.0 μm particles at via sidewalls. Filtration through 0.2 μm polypropylene membrane and continuous surfactant replenishment at 0.05 vol% per batch extend bath life to 3,000–4,500 wafer passes. Compliance includes SEMI C35 trace metal control and ISO 14644-1 Class 5 bath filling conditions. Terminal products include 2/2 μm line/space redistribution layers, copper pillar bumps at 30–80 μm pitch, and fan-out wafer-level packages for mobile processors. The process boundary is oxygen ingress: dissolved oxygen above 1.0 mg·L⁻¹ promotes oxidation at the solder cap and should be controlled by nitrogen blanketing of the bath.
Gen 8.5 thin-film transistor array lines that pattern aluminum/molybdenum source-drain electrodes with phosphoric-acetic-nitric wet etch accumulate a mixed metal-organic residue at the undercut edge. The stripper is diluted with deionized water to 65–75 vol% and applied through a linear nozzle spray with 1.8–2.4 kg·cm⁻² impingement pressure at 40–50 °C for 90–150 s. The fresh solution contains a fluoride-complexing agent at 0.5–1.0 wt% and a nonionic fluorosurfactant at 0.06–0.12 wt% to reduce surface tension to 28–32 mN·m⁻¹, which prevents de-wetting on indium tin oxide test pads. Al/Mo stack etch rate during stripper contact is limited to <0.2 Å·min⁻¹ for aluminum and <0.1 Å·min⁻¹ for molybdenum by pH adjustment to 8.5–9.5. Metal contamination on the backplane after stripping is kept below 5×10¹² atoms·cm⁻² for sodium and iron, measured by total reflection X-ray fluorescence per SEMI C35 consensus. Terminal products include 4K high-refresh-rate liquid crystal modules and active-matrix organic light-emitting diode panels. The process boundary occurs at acid carryover above 0.2 N; acetic/nitric droplets from the prior etch module lower local pH below 7.0, causing molybdenum oxide defect spots. A heated air knife at 40 °C and 0.5 MPa is positioned before the strip chamber to remove acid carryover.
In semi-additive process HDI manufacturing, a negative-acting dry film of 20–30 μm thickness is laminated to electroless copper seed layers, exposed, developed, and then used as a template for pattern electroplating of 15–40 μm copper tracks. Post-plating resist removal is performed with an aqueous electronic/EL grade stripper diluted to 2.5–4.0 wt% tetramethylammonium hydroxide, 1.0–2.0 wt% monoethanolamine, 0.5–1.5 wt% ethylene glycol monobutyl ether, and 0.3–0.8 wt% sodium gluconate as a copper-complexing inhibitor. Conveyorized spray chambers operate at 48–55 °C, 2.0–3.0 kg·cm⁻², with dwell time set at 40–70 s; subsequent double cascade rinses are delivered at 0.8 MPa and 20–25 °C. Free alkalinity in the working bath is titrated against 0.1 N hydrochloric acid and held at 0.45–0.65 eq·L⁻¹; a drop below 0.40 eq·L⁻¹ causes resist swelling instead of dissolution, leaving 5–15 μm acrylate residues between copper features. Bath life is terminated at 12 g·L⁻¹ dry film loading; online 10 μm polypropylene depth filtration and oil skimming are run at 1.5 bath volumes per hour. Terminal products are HDI boards with 40/40 μm line/space for mobile camera modules and chip-scale package substrates. Compliance verification follows IPC-4101 base material compatibility and IPC-6012 Class 3 plated-through hole reliability; surface ion contamination after stripping is measured by ionograph extraction and limited to ≤1.5 μg NaCl·cm⁻².
| Sector | Bath/spray temperature | Contact time | Agitation/pressure | Key substrate etch limit |
|---|---|---|---|---|
| IC BEOL residue | 65–72 °C immersion; 70–80 °C spray | 14–20 min; 90–150 s | 0.1 μm filtration; 1.6–2.2 bar spray | Cu <1 Å·min⁻¹ |
| Wafer-level RDL | 70–78 °C | 10–20 min | 40 kHz megasonic at 0.8–1.2 W·cm⁻² | TiW <0.5 Å·min⁻¹ |
| Gen 8.5 FPD array | 40–50 °C | 90–150 s | 1.8–2.4 kg·cm⁻² spray | Al <0.2 Å·min⁻¹; Mo <0.1 Å·min⁻¹ |
| HDI PCB resist | 48–55 °C | 40–70 s | 2.0–3.0 kg·cm⁻² spray | Cu below electroplating thickness tolerance |
Thick photoresist sacrificial structures of 10–100 μm are used to define air gaps in MEMS accelerometers, pressure sensors, and RF switches. The resist is often thermally crosslinked by deep reactive-ion etching sidewall passivation or electroplating at 60–80 °C, requiring a stripper with high solvency but low surface tension in the final rinse. The electronic/EL grade stripper is used at 50–65 °C in a batch immersion tool with 20–30 rpm wafer rotation; exposure time is scaled at 1.5–2.0 min·μm⁻¹ of resist thickness. The working solution consists of 50–70 vol% polar aprotic solvent, 10–20 vol% glycol ether, 0.5–1.5 vol% aqueous tetramethylammonium hydroxide, and 0.1–0.5 vol% amphoteric surfactant. After stripping, the rinse sequence uses deionized water with 0.1 vol% surfactant to lower surface tension below 30 mN·m⁻¹ at 25 °C; direct transfer from the hot bath to cold deionized water is prevented to avoid thermal shock of high-aspect-ratio silicon beams. Terminal MEMS products include triaxial accelerometers with 2 μm comb gaps and automotive pressure-sensor diaphragms. Compliance for electronic/EL grade materials is set by SEMI C35 trace metal limits and ASTM D5127 water quality; for non-implantable devices no additional biocompatibility assessment applies. Process boundary: pH above 9.0 at 65 °C attacks aluminum bond pads and releases hydrogen gas, which can lift electroplated nickel masses.
Compound semiconductor LED wafers with p-contact metallization patterned by negative resist lift-off accumulate organic residue and metal edge flakes that must be removed before current spreading measurement. The stripper is heated to 35–45 °C only; higher temperatures increase the etch rate of AlInP current spreading layers and indium-containing III-V substrates. The bath is agitated with 40 kHz ultrasonic transducers at 0.5–1.0 W·cm⁻² for 8–15 min, or applied in a single-wafer spray at 1.0–1.5 bar with 60 s cycle time. The pH is buffered to 8.0–9.0 by a tertiary amine at 0.5–1.0 wt%. GaAs etch rate under these conditions remains below 0.1 Å·min⁻¹; InP below 0.2 Å·min⁻¹. Metal ion specifications are critical: copper, iron, and zinc in the neat stripper must be below 5 ppb each by ICP-MS according to SEMI C35, because copper on GaN surfaces creates non-uniform contact resistance and increases forward voltage. Terminal products include mid-power 0.2–1.0 W LED chips for backlighting and horticultural fixtures. Bath lifetime is limited to 2,000 wafer equivalents or 48 h, whichever occurs first, due to ester hydrolysis of the solvent and subsequent pH drop.
Photovoltaic heterojunction and TOPCon cell processes use organic ink and plating resist masks for copper or silver electrode definition; these masks must be removed without altering the passivation stack. The electronic/EL grade stripper is applied at 25–35 °C for 3–8 min in a batch spray processor on 210 mm silicon wafers. The working formulation is diluted to 50–60 vol% with deionized water, reducing the etch rate on indium tin oxide to below 0.05 Å·min⁻¹; the pH is set to 6.5–7.5 to prevent dissolution of the amorphous silicon passivation layer. The bath is monitored for silver and copper buildup; silver above 0.5 ppm causes electrochemical migration onto the silicon surface and must be removed by chelating resin. The terminal products are heterojunction solar cells with 23–25% conversion efficiency and TOPCon cells with 24–25% efficiency. Compliance anchors to SEMI PV2 for photovoltaic chemical purity and IEC 61215 for module reliability after lamination; the stripper itself must not leave organic carbon residues above 10 ng·cm⁻² as measured by contact angle mapping. Published data for this specific configuration is limited because most photovoltaic lines use proprietary alkali-based removers.
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ST-OA-E/EL-200 is described as the stripper of organic & aqueous systems, electronic/EL grade, for post-ash and post-etch residue removal on 300 mm silicon and compound semiconductor wafer lines. The single-liquid formulation combines a dipolar aprotic carrier solvent, ultrapure water, and a buffered corrosion-inhibitor package; it is filtered through 0.05 µm fluoropolymer cartridges and packaged under nitrogen in 20 L fluoropolymer canisters or 200 L fluoropolymer-lined drums. The carrier solvent is N-methyl-2-pyrrolidone-free, avoiding the restriction on N-methyl-2-pyrrolidone set out in Regulation (EC) No 1907/2006, Annex XVII, entry 71. The product removes positive-tone i-line and 193 nm photoresist, bottom anti-reflective coating residue, and halogen-containing post-etch polymer from copper, aluminum, cobalt, silicon dioxide, and silicon nitride surfaces.
Electronic/EL-grade quality control focuses on electrochemically active metal ions and submicrometer particle burden. Release testing uses inductively coupled plasma-mass spectrometry after 10-fold preconcentration, with individual Na, K, Ca, Fe, Cu, and Zn controlled below 10 ppb and total critical cations below 50 ppb. Particle counts at ≥0.2 µm are held below 50 counts/mL by optical particle counter calibrated to ISO 21501-4:2018.
General-purpose organic stripping products used in metal-finishing and mold-compound operations typically allow individual metal impurities in the 100–1,000 ppb range and are not packaged under particle-controlled headspace. Electronic/EL-grade material must satisfy SEMI C8-0218 limits for solvent circuitry and must be handled in cleanroom environments classified to ISO 14644-1:2015 Class 5 or better. The primary differentiators are cation burden, particle cleanliness, water content, flash point, and packaging headspace oxygen below 5 vol%. Table 1 lists target specification windows used as incoming quality-control criteria.
Table 1. Target specification windows for ST-OA-E/EL-200.
| Property | Test method | Target specification |
|---|---|---|
| Density at 25 °C | ASTM D4052-22 | 1.02–1.08 g/cm³ |
| Kinematic viscosity at 25 °C | ASTM D445-21 | 1.5–4.0 mm²/s |
| Closed-cup flash point | ASTM D93-20 | >100 °C |
| Water content | ASTM E203-16 | 2.0–8.0 wt% |
| pH at 10 wt% in deionized water | ASTM E70-19 | 9.0–11.5 |
| Surface tension at 25 °C | ASTM D1331-20 | 28–35 mN/m |
| Individual metal impurities Na, K, Ca, Fe, Cu, Zn | SEMI C8-0218 / ICP-MS | <10 ppb each |
| Particle count ≥0.2 µm | ISO 21501-4:2018 | <50 counts/mL |
Compliance is not limited to bulk liquid values. Incoming containers are sampled from the top and bottom after 7 days of quiescent storage to detect settling of corrosion inhibitors. A batch is rejected if bottom-to-top pH difference exceeds 0.2 pH units or if particle counts exceed 100 counts/mL after 30 min of recirculation through a 0.1 µm PTFE filter.
Because the product is miscible with both organic and aqueous residues, it may be diluted with deionized water up to 20 vol% without phase separation at 25 °C. Phase behavior is measured by cloud-point titration; cloud point for a 10 wt% aqueous dilution is below 5 °C. This differentiates it from purely aqueous strippers that require strong alkalis and from purely organic strippers that cannot hydrate or hydrolyze post-ash salts.
Bath make-up in immersion tools uses stainless-steel or PTFE-lined tanks with nitrogen blanket at 3–5 kPa gauge. Dilution is performed only with ultrapure water conforming to ASTM D5127-13(2018) Type E-1.2; untreated city water introduces bicarbonate alkalinity that raises pH drift and destabilizes the buffer. Agitation is maintained at 10–20 strokes/min for rack immersion because higher mechanical energy can strip the copper passivation layer and raise the copper etch rate above 0.5 nm/min. Ultrasonic agitation at 40 kHz is permitted for silicon dioxide test structures but is not recommended for damascene wafers with exposed porous low-k dielectric. Materials of construction for bath tanks are electropolished 316L stainless steel with surface roughness Ra below 0.4 µm; elastomer seals are perfluoroelastomer or fully fluorinated. Polyvinyl chloride and polycarbonate components are not recommended because the carrier solvent can induce environmental stress cracking.
On a 300 mm single-wafer spray-puddle tool, ST-OA-E/EL-200 is dispensed through a PTFE diaphragm pump at 150–300 mL per wafer. The puddle is held for 60–120 s at a wafer surface temperature of 70–85 °C. The wafer then receives ultrapure-water rinse at 22 °C and spin-dry under nitrogen. The process removes 1–3 µm thick 193 nm resist without a separate dry-ash step. The puddle time is the critical parameter; a deviation of ±5 s from the qualified condition shifts residue defect density on 248 nm photoresist. Published data for this specific configuration is limited; inline defect inspection on a dark-field laser scattering tool has shown increased residue when dispense volume falls below 150 mL on hydrophobic low-k substrates.
Compared with N-methyl-2-pyrrolidone-based strippers, the product exhibits lower vapor pressure at chuck temperature, reducing solvent condensation inside the wafer-handler robot area. The closed-cup flash point above 100 °C permits use in equipment not rated for low-flash solvents; however, the product is not classified as nonflammable, and local exhaust ventilation must maintain duct concentration below 25% LEL. The product is miscible with water at process temperature, so intermediate rinse is not required before ultrapure-water rinse.
For process comparison, Table 2 summarizes measurable differences between ST-OA-E/EL-200, conventional N-methyl-2-pyrrolidone-based solvent strippers, and tetramethylammonium hydroxide-based aqueous developers. The values are used for feasibility screening only.
Table 2. Comparative process parameters.
| Parameter | ST-OA-E/EL-200 | NMP-based solvent stripper | TMAH-based aqueous developer |
|---|---|---|---|
| pH at 10 wt% | 9.0–11.5 | 7.0–9.0 | >13.0 |
| Cu etch rate at 75 °C, 60 min | 0.3–0.8 nm/min | 1.0–3.0 nm/min | >10 nm/min |
| Al-0.5Cu etch rate at 75 °C | 0.3–0.8 nm/min | 0.5–2.0 nm/min | >100 nm/min |
| Closed-cup flash point | >100 °C | 86 °C | Not applicable, aqueous |
| Removal of 1–3 µm 193 nm resist | Complete at 60–120 s | Complete at 60–90 s | Partial; leaves hydrophobic residue |
| Low-k dielectric swelling risk | Low at ≤120 s | Moderate to high | High |
Aluminum bond pads are passivated by the inhibitor package. The etch rate on sputtered Al-0.5Cu coupons measured by stylus profilometry after 60 min immersion at 75 °C is 0.3–0.8 nm/min. Electroplated copper surface roughness remains below 0.5 nm RMS when measured by atomic force microscopy on 1 µm copper films. Titanium and tungsten via plugs show no measurable weight loss after 24 h immersion at 25 °C. This behavior differentiates the product from strongly alkaline or hydroxylamine-containing strippers that can attack titanium nitride and aluminum interfaces. For copper-damascene structures, the product is compatible with exposed TaN/Ta barrier and SiCN etch-stop layers. The selectivity window is maintained by keeping pH below 11.5 and by avoiding chlorinated solvents; chloride content in the fresh bath is below 1 mg/L.
Selectivity windows narrow when the product contacts cobalt-tungsten-phosphide passivation layers or porous methylsilsesquioxane low-k dielectrics. CoWP dissolution is suppressed by maintaining pH between 9.0 and 11.5 and by keeping chloride below 5 mg/L in the bath. At pH above 11.5, CoWP etch rate increases abruptly from 0.2 nm/min to above 2.0 nm/min; the valid pH window is therefore ≤±0.5 pH units. For porous methylsilsesquioxane films with dielectric constant k = 2.2–2.5, continuous liquid flow is required rather than a stagnant puddle. Solvent residence time on low-k sidewalls must not exceed 120 s; longer exposure produces a dielectric constant shift greater than 0.2 as measured by mercury-probe capacitance.
When tetrachloroethane is used as a comparison immersion solvent, low-k damage is faster because of high cohesive energy and swelling stress; ST-OA-E/EL-200 avoids the high swelling stress associated with halogenated hydrocarbons. Copper migration into 2 µm pitch interlayer dielectric test structures has not been observed after 100 wafer passes when the bath copper concentration is held below 10 ppm by ICP-MS. This limit is more restrictive than for general solvent recycling.
In wafer-level packaging, the product is used intermittently for post-polymer rework of redistribution-layer resists. The recommended process uses a 10 min immersion at 65 °C followed by isopropanol rinse and deionized-water rinse. For polyimide and benzocyclobutene passivation films, adhesion loss is evaluated by tape test per ASTM D3359-17; a rating of 5B is retained after 30 min exposure at 65 °C. On GaAs and InP wafers, the product should not be used on gold-plated bond pads at pH above 10.5 for extended periods because pH-assisted dissolution of gold is accelerated by chloride; published data for this specific configuration is limited. Recommended contact time is limited to 5 min at 25 °C for III-V substrates with exposed gold.
In batch immersion, bath life is limited by chloride and sulfate accumulation from dissolved post-etch residues and by evaporation of the dipolar aprotic carrier. Chloride concentration is monitored by ion chromatography with a control limit of 5 mg/L; above this limit, aluminum bond pads develop pit corrosion rather than uniform etching. Sulfate is controlled at 10 mg/L because sulfate esters accelerate copper oxidation. Carrier solvent concentration is measured by gas chromatography with flame ionization detection and maintained at 85–100% of initial value. If carrier concentration falls below 85%, novolak dissolution capacity drops and resist residues remain on via sidewalls.
Bath hardware includes filtration through 0.1 µm PTFE membranes at 2–4 turnovers per hour. Nitrogen blanketing is maintained at −20 Pa relative to cleanroom to reduce carrier evaporation. Bath replacement is triggered by total critical metals above 50 ppb, chloride above 5 mg/L, or batch age beyond 72 h, whichever occurs first. The bath must not be combined with hydroxylamine or strong oxidizer additives because exothermic reaction raises the local temperature above the flash point.
Spent product containing dissolved photoresist and organometallic residues is classified as a combustible liquid with flash point above 100 °C; it must be segregated from strong oxidizers and from aqueous waste with pH below 2. The waste stream is neutralized to pH 6–8 before biological treatment. Halogenated solvent content is below 1 wt%, and the formulation does not contain substances listed in Annex II of the RoHS Recast 2011/65/EU at concentrations above 0.1 wt% in homogeneous material.
Post-strip residue population on 300 mm test wafers is characterized by scanning electron microscopy review of 10 edge dies and 10 center dies at 2 kV accelerating voltage. The product leaves no detectable organometallic residue when wafers are processed within the stated bath life and rinsed with ultrapure water for 60 s at 22 °C. Residue count on copper pads remains below 1 defect/cm² after 100 wafer passes in a 200 L bath. This acceptance test is performed with patterned post-etch residue from fluorinated plasma processes; structures with aluminum bond pads require additional post-rinse in deionized water to remove trace chloride.
