| HS Code | 698200 |
| Chemical Formula | CH3OH |
| Molecular Weight | 32.04 g/mol |
| Cas Number | 67-56-1 |
| Purity | >= 99.9% (Electronic/EL Grade) |
| Appearance | Clear, colorless liquid |
| Water Content | <= 500 ppm |
| Resistivity | >= 10 MΩ·cm |
| Evaporation Residue | <= 5 ppm |
| Acidity As Ch3cooh | <= 20 ppm |
| Chloride Cl | <= 0.1 ppm |
| Sulfate So4 | <= 0.1 ppm |
| Heavy Metals As Pb | <= 0.1 ppm |
| Density At 20 C | 0.791 g/cm³ |
| Boiling Point | 64.7°C |
| Flash Point | 11°C |
As an accredited Methanol Electronic/EL Grade factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Methanol Electronic/EL Grade, 4L bottle: high-purity solvent in amber glass bottle with PTFE cap and safety labels. |
| Container Loading (20′ FCL) | 20' FCL container loading of Methanol Electronic/EL Grade requires secure drum placement, proper ventilation, and hazardous material compliance. |
| Shipping | Ship Methanol Electronic/EL Grade as UN1230, Methanol, Class 3, PG II. Use sealed, grounded containers and dedicated hazardous-material transport. Segregate from oxidizers and foodstuffs. Ensure proper labeling, placarding, and documentation. Keep away from ignition sources, monitor for leaks, and follow spill-containment procedures throughout transit. |
| Storage | Methanol Electronic/EL Grade must be stored in tightly sealed, corrosion-resistant containers, preferably stainless steel or approved HDPE, under inert nitrogen to prevent moisture uptake and impurity contamination. Keep in a cool, dry, well-ventilated area away from heat, ignition sources, and oxidizers. Use proper grounding and bonding, with clear labeling and regular container integrity checks. |
| Shelf Life | Shelf Life: 12 months when stored unopened in the original container under recommended conditions, protected from moisture and contamination. |
In back-end wafer thinning and dicing operations for silicon, gallium arsenide, and indium phosphide substrates, methanol Electronic/EL Grade is charged as a neat solvent at 100 vol% into 40 kHz PFA ultrasonic immersion tanks. The solvent removes rosin-based waxes and polyetherimide mounting adhesives from ground wafer surfaces before die attach inspection. Bath temperature is maintained between 25 °C and 35 °C, and immersion time is set from 180 s to 300 s depending on wafer thickness and adhesive loading. After ultrasonic treatment, the cassettes pass through a three-stage deionized water cascade with resistivity not less than 18.2 MΩ·cm and final drying under filtered nitrogen at 0.3 m/s. The solvent specification is not a general cleaning statement; post-evaporation cation residue must remain below 10 ppb for sodium, potassium, calcium, and iron individually, with evaporation residue limited to 2 ppm and chloride below 50 ppb under SEMI C18. These thresholds protect surface leakage current on passivated areas and prevent pad contamination prior to wire bonding. Downstream terminal components include RF bulk acoustic wave filters, MEMS pressure sensors, and indium phosphide photodetectors.
| Parameter | Electronic/EL Grade Limit | Reference Method |
|---|---|---|
| Water content | ≤300 ppm | ASTM E203-22 Karl Fischer titration |
| Evaporation residue | ≤2 ppm | ASTM D1353-13 |
| Chloride | ≤50 ppb | Ion chromatography per SEMI C18 |
| Individual alkali/transition metals | ≤10 ppb | ICP-MS per SEMI C18 |
| Particle count ≥0.1 µm | ≤10 particles/mL | LPC per SEMI C18 |
Liquid-crystal display front-plane lines operate a final clean immediately before indium tin oxide sputtering, and methanol Electronic/EL Grade is used for its ability to wet polished 0.7 mm soda-lime glass without attacking alignment-layer precursor films already deposited on the substrate. The cleaning fluid is used neat at 100 vol%; the water limit is fixed at ≤300 ppm because higher moisture increases the frequency of post-drying micro-spotting defects on sputtered ITO layers. The tank is constructed from 316L stainless steel with electropolished surfaces, and the liquid is recirculated through 0.05 µm PTFE point-of-use filters at 18–22 L/min. Process control monitors density at 0.786–0.791 g/cm³ at 20 °C and refractive index to detect water ingress from humid ambient air. Air-knife drying follows with 0.1 µm filtered nitrogen, and the separation distance is set between 3 mm and 5 mm to prevent re-entrainment of charged glass dust. The terminal parts are TFT-LCD cell assemblies and projected-capacitive touch sensor arrays. The relevant release standard is SEMI C18; water content is confirmed by ASTM E203-22, and trace metal verification uses ICP-MS. Flash point of methanol is 11 °C, so the cleaning module is interlocked with lower flammable limit detection at 10% LEL and local exhaust velocity not less than 0.5 m/s.
After monocrystalline silicon wafers undergo KOH-based anisotropic texturing for PERC or heterojunction front-surface pyramids, the primary rinse task is removal of potassium silicate residues from the troughs of 2–4 µm pyramidal structures. Methanol Electronic/EL Grade is blended at 1.0–3.0 vol% with deionized water in the overflow rinse bath because its viscosity of 0.54 mPa·s at 25 °C is lower than the 2.04 mPa·s figure for isopropanol, allowing faster mass transport from high-aspect-ratio surface features. The bath operates at 25–30 °C with overflow rates between 5 L/min and 10 L/min per wafer carrier, followed by a dilute HF oxide removal step. Methanol volatility requires that the rinse module be exhausted at not less than 0.5 m/s and that the LEL alarm threshold be set at 10%; the flash point of 11 °C and autoignition temperature of 464 °C define the risk envelope for equipment layout. The addition lowers surface tension from the pure-water baseline of 72 mN/m at 25 °C, improving wetting of the textured silicon surface without introducing sodium, potassium, or calcium above 10 ppb when the EL-grade specification is maintained. Downstream terminal products are monocrystalline PERC cells and hydrogenated amorphous silicon heterojunction cells used in utility-scale modules.
Direct methanol fuel cell stacks receive methanol Electronic/EL Grade because industrial-grade methanol contains alkali and sulfur-containing impurities that accelerate membrane conductivity loss and Pt-Ru anode catalyst poisoning. The supplied solvent is diluted with deionized water to 1.0–3.0 M methanol, equivalent to approximately 3.2–9.6 wt%, and metered into the anode recirculation loop at 0.2–0.5 mL/min·cm² of membrane electrode assembly active area. Heat removal is controlled by stack coolant temperature at 60–80 °C, and the anode loop uses a 0.1 µm PTFE filter to capture particulate contamination released from bipolar plates. The methanol feed must remain below 10 ppb for sodium and potassium and below 50 ppb for chloride because these ions compete with proton transport in perfluorosulfonic acid membranes and reduce open-circuit voltage on repeated load cycling. The water used for dilution is degassed to <1 ppm dissolved oxygen to limit peroxide formation, and the mixing tank is nitrogen-blanketed to exclude atmospheric carbon dioxide. Published stack-level data for every impurity threshold is limited, but the raw methanol specification is controlled against SEMI C18, and conductivity of the diluted feed is monitored inline at ≤1.0 µS/cm after mixing. Terminal products in this segment include portable fuel cell generators, off-grid telemetry power units, and lightweight auxiliary power supplies for unmanned aerial vehicles.
Boron precursor production for borophosphosilicate glass chemical vapour deposition starts with the esterification of boric acid in methanol Electronic/EL Grade. The reaction is operated at a stoichiometric molar ratio of 3:1 methanol to boric acid, with additional methanol maintained in the condenser loop at 6:1 total feed to support azeotropic removal of water and drive completion. Fractional distillation under dry nitrogen separates trimethyl borate from the methanol/trimethyl borate azeotrope at a column top temperature of 55–68 °C depending on vacuum level; this range is derived from atmospheric vapour-liquid equilibrium data for methanol/trimethyl borate mixtures. Water in the feedstock must remain below 300 ppm, and chloride below 50 ppb, because residual halide becomes entrained in the boron oxide film and shifts dielectric loss. The distillation train uses 316L stainless steel and PTFE packing, with reflux ratios between 3:1 and 8:1 to maintain head space moisture below 10 ppm. The purified precursor is then vaporized in low-pressure CVD equipment at 350–450 °C with silane and phosphine for BPSG layers on patterned logic wafers. The terminal films include borophosphosilicate glass passivation, borosilicate optical layers, and boron doping sources for solid-state diffusion processes.
For cleanroom laboratories that support semiconductor chemical distribution systems, methanol Electronic/EL Grade is used as a high-purity diluent in ion chromatography and ICP-MS sample preparation because the solvent background for sodium, potassium, calcium, and iron is specified at ≤10 ppb for each element. Routine dilutions are prepared at 1:10 or 1:100 (v/v) in perfluoroalkoxy sample bottles, and the final solution is filtered through 0.05 µm PTFE syringe filters immediately before injection. The methanol is also used as a 5 vol% mobile phase modifier in ion chromatography when separating monovalent cations from 300 mm wafer surface extracts, although published data for this specific method is limited. The use of electronic-grade rather than HPLC-grade methanol is driven by the need for low total residue after evaporation, not by chromatographic baseline noise alone. The reference test methods for water and residue are ASTM E203-22 and ASTM D1353-13, respectively. The terminal products are calibration reports, process chemical release certificates, and out-of-control action summaries for fabs running high-mix logic and power devices.
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Methanol Electronic/EL Grade is a high-purity methanol stream supplied to semiconductor wafer cleaning, flat-panel display, photolithography, and precision surface preparation operations. The material is identified as methanol with CAS 67-56-1, molecular formula CH3OH, and UN shipping classification UN 1230, Class 3, Packing Group II. Commercial product designations vary by supplier; model codes usually refer to packaging configuration, trace-metal tier, and analytical certificate content rather than a universal industry model. A complete product model statement for procurement is therefore a concatenation of grade, specification standard, and container: Methanol, Electronic/EL, SEMI C18, H2O ≤ 500 ppm, Na ≤ 100 ppb, 200 L lined steel drum, nitrogen-blanketed. This product is not defined by a single assay value but by simultaneous control of organic, ionic, and particulate impurities across the lot.
Relevant physical constants include a boiling point of 64.6 °C, freezing point of -97.8 °C, density of 0.7915 g/cm³ at 20 °C, and viscosity of 0.59 mPa·s at 20 °C. The closed-cup flash point is 11 °C, and flammability limits in air are 6.0 vol% to 36.0 vol%. Vapor pressure at 20 °C is 12.8 kPa, and surface tension is approximately 22.5 mN/m at 25 °C. Methanol is hygroscopic; open reservoirs absorb water from ambient air, which is a principal process variable in high-purity cleaning and solvent-exchange drying.
The electronic/EL distinction is derived from specification documents such as SEMI C18, which sets limits for methanol assay, water, evaporation residue, free acid, chloride, sulfate, phosphate, and individual trace metals. Unlike industrial methanol, which is sold primarily on distillation range and total acidity, electronic/EL methanol carries lot-specific certificates for metal ions, anions, and particle levels. Representative upper limits for a standard EL lot are compiled in the following table; they are not universal purchase specifications, but they reflect common lot-release values documented in semiconductor chemical supplier data.
| Parameter | Unit | Representative limit | Test method |
|---|---|---|---|
| Methanol assay | area% | ≥ 99.9 | GC-FID, internal normalization |
| Water | ppm | ≤ 500 | ASTM E203 coulometric Karl Fischer |
| Evaporation residue | ppm | ≤ 5 | ASTM D1353 gravimetric |
| Total acidity as CH3COOH | ppm | ≤ 5 | ASTM D1613 |
| Chloride, Cl− | ppm | ≤ 1 | Ion chromatography |
| Sulfate, SO42− | ppm | ≤ 1 | Ion chromatography |
| Phosphate, PO43− | ppb | ≤ 100 | Ion chromatography |
| Sodium | ppb | ≤ 100 | ICP-MS |
| Potassium | ppb | ≤ 100 | ICP-MS |
| Iron | ppb | ≤ 50 | ICP-MS |
| Copper | ppb | ≤ 50 | ICP-MS |
| Zinc | ppb | ≤ 50 | ICP-MS |
| Particles ≥ 0.2 µm | particles/mL | ≤ 50 | Laser particle counter |
Higher-purity tiers, often called low-sodium or ULSI electronic grade, reduce sodium and potassium to 10 ppb or lower and may specify particles at ≥ 0.1 µm to 10 particles/mL. These tiers are vendor-defined and should be verified against the intended process node, because a standard EL lot may not satisfy the metal budget of advanced logic or charge-sensitive devices.
In wet-bench immersion cleaning of 150 mm and 200 mm wafers, methanol EL grade is pumped from 20 L returnable canisters or bulk day tanks through 0.05 µm PTFE filters to overflow rinse baths. Bath temperature is normally maintained between 20 °C and 35 °C. Open unblanketed baths absorb atmospheric water at reported rates exceeding 20 ppm per shift at relative humidity above 60%; this shifts water content toward the specification limit and can produce water spotting after spin-rinse-dry. Production-scale equipment therefore applies dry nitrogen blankets at 5–10 psig and uses bleed-and-feed replenishment to keep water below 500 ppm. The lower water content and controlled chloride concentration in EL material prevent ionic residue streaks on aluminum and copper interconnect surfaces after drying.
The difference between methanol grades is primarily a purification-train and packaging-control issue, not a single distillation-cut issue. Industrial methanol typically contains water, ethanol, higher alcohols, acetone, and aldehydes that are acceptable as fuel or chemical-intermediate impurities but that interfere in microelectronic cleaning. ACS reagent methanol is refined to controlled assay and residue limits, but it is not routinely delivered with particle counts or ppb-level metal certification. Electronic/EL methanol adds deionization, organic acid removal, sub-boiling distillation or distillation under inert gas, and filtration into cleaned containers. This sequence lowers chloride, sulfate, and metal cations to levels that do not add mobile ions to wafer surfaces.
| Property | Industrial | ACS reagent | Electronic/EL |
|---|---|---|---|
| Assay | 99.0–99.85% | ≥ 99.8% | ≥ 99.9% |
| Water | ≤ 1500 ppm | ≤ 1000 ppm | ≤ 500 ppm |
| Evaporation residue | ≤ 20 ppm | ≤ 5 ppm | ≤ 5 ppm |
| Chloride | not specified | ≤ 1 ppm | ≤ 1 ppm |
| Sulfate | not specified | ≤ 1 ppm | ≤ 1 ppm |
| Trace-metal control | total metals 10 ppm or higher | single cations in the 1 ppm range | single cations ≤ 100 ppb, ULSI ≤ 1 ppb |
| Particle count | not controlled | not controlled | ≤ 50 particles/mL at ≥ 0.2 µm |
Electronic/EL methanol also differs from HPLC or LC-MS grade methanol. HPLC-grade methanol is optimized for UV transmittance, fluorescence background, and non-volatile residue; it is not necessarily certified for chloride, sulfate, or particle counts. Conversely, electronic/EL methanol may not carry ultraviolet absorbance performance required for high-sensitivity chromatography. The two grades should not be interchanged without reviewing lot-specific certificates for the intended use.
Compared with electronic-grade isopropyl alcohol, methanol EL grade has a lower boiling point, a lower viscosity, and a higher polar solubility parameter, but it is systemically toxic at lower exposure levels. Electronic-grade isopropyl alcohol is often preferred where personnel exposure is difficult to control; methanol is selected where faster evaporation and higher solvency for polar photoresist residues are required. The two are not direct drop-in replacements without re-qualifying drying time, residue levels, and material compatibility.
SEMI C18 certification requires analytical methods that minimize environmental contamination. Cation determinations use ICP-MS with internal standards and blank subtraction; anion determinations use ion chromatography with suppressed conductivity. Particle counts are run by optical liquid particle counters on continuously flowing, degassed samples. Sample containers are fluoropolymer or precleaned glass with TFE-lined caps. A lot certificate for electronic/EL methanol should include the actual measured value for each parameter, not only a pass/fail statement. Quality agreements commonly require retaining 500 mL retains per lot for a defined retention period, and some end users re-test water content and particle counts at point-of-use because packaging and transfer lines contribute more than the bulk material.
On photoresist edge-bead removal tools, methanol EL grade is dispensed through a nozzle at the wafer edge while the wafer rotates at 800–1200 rpm. The solvent dissolves residual photoresist and prevents re-deposition onto the bevel. Evaporation rate and low residue leave no visible film after 30 s of spin-off. The edge-bead process is sensitive to water content: water above 500 ppm reduces the dissolution rate of certain novolac resists and increases the risk of airborne particle attachment. In contrast, industrial methanol may contribute sodium and iron to the bevel surface; after plasma etch and metal deposition, those mobile ions migrate to device-adjacent regions and shift threshold voltage. Published data for wafer-level threshold shift caused by specific methanol impurities is limited, but the ionic-budget argument is well established in microcontamination control.
Dilution of epoxysilanes and methacrylsilanes in methanol electronic/EL grade produces primer solutions for glass, silicon oxide, and ITO surfaces. A representative solution contains 2–5 wt% silane monomer and 1–2 wt% deionized water in methanol. The solvent’s low water content is used to control hydrolysis; excess water or acidity in industrial methanol causes premature condensation and gelation. Chloride in solvent must remain below 1 ppm because chloride can accelerate aluminum pad corrosion after the primer is cured. Batch-to-batch adhesion uniformity is also affected by trace metals that complex with the silane functionality and change film cross-linking. Under process conditions, an open container of methanol EL grade can absorb enough water within 24 h to alter hydrolysis stoichiometry; therefore, point-of-use nitrogen blanketing and sealed dispensing are required.
In flat-panel display and OLED manufacturing, methanol EL grade is used for cleaning fine metal masks after shadow-mask deposition and for removing organic residues from ITO-coated glass. The cleanliness requirements are driven by sodium and potassium mobility in organic layers; even 100 ppb sodium in cleaning solvent can become concentrated at the surface after evaporation. Display fabricators therefore specify low-sodium electronic/EL methanol and filtration to 0.1 µm. Published dark-spot failure thresholds for specific methanol residues are limited; internal specifications typically set total metals below the levels shown in the standard EL table and impose additional particle counts. That limitation should be anticipated when qualifying a new supplier.
Operational boundaries derive from flammability, toxicity, and moisture sensitivity. The solvent is classified under GHS as H225 Highly flammable liquid and vapor; H301+H311+H331 Toxic if swallowed, in contact with skin, or if inhaled; and H370 Specific target organ toxicity. Storage and transfer areas require explosion-proof electrical classification according to NFPA 497 or EN 60079-10-1, with closed piping or local exhaust. Atmospheric exposure limits are 200 ppm 8-hour TWA under OSHA and 250 ppm short-term exposure under ACGIH. When unattended, electronic/EL methanol should not be stored in open containers, and it should not be mixed with strong oxidizers such as concentrated nitric acid or hydrogen peroxide because exothermic decomposition and flammable vapor generation may occur. Transfer equipment should be constructed of 316L stainless steel, PVDF, or PTFE; avoid natural rubber and EPDM seals where low extractables are required.
