| HS Code | 934895 |
| Chemical Composition | Mixture of organic solvents such as propylene glycol monomethyl ether acetate (PGMEA) and methyl ethyl ketone (MEK) |
| Appearance | Clear, colorless liquid |
| Purity | High-purity grade with low metallic and particulate contamination |
| Boiling Point | Approximately 120–160°C depending on formulation |
| Flash Point | Above 25°C (closed cup), flammable liquid |
| Density | Approximately 0.85–1.05 g/cm³ at 20°C |
| Solubility | Fully miscible with common photoresist solvents and organic coating formulations |
| Evaporation Rate | Fast to moderate evaporation rate relative to n-butyl acetate |
| Vapor Pressure | Low to moderate at room temperature, typically less than 10 kPa |
| Application | Used in photolithography to remove edge bead polymer residues from wafer edges and backside |
| Storage Condition | Store in tightly sealed containers away from ignition sources and direct sunlight |
As an accredited Edge Bead Remover (EBR) factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Edge Bead Remover (EBR) is packaged in a 950 mL HDPE bottle with a safety-sealed, child-resistant cap for controlled dispensing. |
| Container Loading (20′ FCL) | 20′ FCL: UN-approved drums/palletized EBR, secured and labeled, with dangerous goods documentation for safe transport. |
| Shipping | Edge Bead Remover (EBR) is a flammable solvent requiring hazmat-compliant shipping. It must be transported via ground only, in UN-approved containers, with proper labeling, documentation, and segregation from incompatible materials. Shipping is restricted to trained carriers, with temperature control and spill-containment measures to ensure safe delivery. |
| Storage | Store Edge Bead Remover in a tightly sealed container in a cool, dry, well-ventilated area, away from heat, open flames, and direct sunlight. Keep it separate from strong oxidizers and incompatible chemicals. Ensure the storage area is properly grounded and equipped with spill containment, following all local safety regulations. |
| Shelf Life | Shelf life is typically 12 months from manufacture when stored sealed at room temperature; refer to label expiry. |
Edge bead formation is inherent to spin coating positive-tone chemically amplified resists onto 300 mm silicon wafers. At spin speeds between 1,500 rpm and 3,000 rpm, resist accumulates as a raised lip at the wafer bevel, creating a contamination source for downstream etch, ion implantation, and scanner stages. In a front-end coater/developer track, the edge bead remover is dispensed undiluted from a top-edge rinse nozzle while the wafer rotates at 500–1,200 rpm; point-of-use dispense volume is 0.6–2.0 mL per wafer, yielding an edge exclusion width of 1.0–3.0 mm. The formulation usage ratio is 100% as supplied, with no water or solvent trimming at the tool. Point-of-use filtration through 0.05–0.1 µm membranes reduces particle-related edge defects. Process compliance is anchored to ISO 14644-1:2015 Class 3/4 cleanroom operation and to wet-chemical module safety evaluations under SEMI S2 and SEMI S8. The coating sequence remains adhesion priming, resist dispense, edge bead removal, backside rinse, soft bake at 90–130°C, immersion or EUV exposure, post-exposure bake, develop, and rinse. In production, insufficient edge rinse flow leaves crescent-shaped resist remnants that detach during etch; excessive flow wicks solvent into the active area and creates CD non-uniformity at the outermost dice. Terminal products from this segment include logic processors, mobile SoCs, ASICs, FPGAs, DRAM, and NAND flash stacks.
GaAs and silicon carbide substrates are smaller and more brittle than silicon, with edge geometry that alters edge bead remover wetting and run-off. After spin-coating 2–10 µm positive resists, the edge bead is removed undiluted at 0.8–2.5 mL per 150 mm GaAs wafer and 1.2–3.5 mL per 200 mm SiC wafer; edge exclusion width is maintained at 2.0–5.0 mm. The edge bead remover is used at 100% as-received, and the dispense sequence is run at reduced spin speed of 300–800 rpm to prevent over-thinning of the resist near the wafer flat or notch. Cleanroom classification is typically ISO 14644-1:2015 Class 5 or better, and the coater/developer equipment is evaluated under SEMI S2 and SEMI S8 for solvent handling. Downstream, the wafer proceeds through soft bake, alignment, exposure, develop, and plasma descum before metal deposition or ion implantation. A process boundary exists at edge bead remover dwell times above 10 s: solvent can wick along microcracks at the wafer edge and undercut the resist line, producing edge CD variation on high-power RF and power-device die. Terminal products include GaN high-electron-mobility transistors, GaAs pHEMT power amplifiers, SiC MOSFETs, and Schottky barrier diodes.
Liquid resists and dry-film resists in wafer-level packaging are coated at 10–100 µm thickness; the resulting edge bead is not a thin organic ridge but a thick annular wall that can survive a single-pass solvent rinse. In this segment, the edge bead remover is used at 100% as-received and dispensed at 2–8 mL per 300 mm wafer with edge exclusion widths from 3.0 mm to 15.0 mm, depending on die-layout keep-out and bump/RDL design rules. Multiple edge rinse passes at 200–700 rpm are required because the thick bead dissolves in layers; a single high-speed pass tends to fold the bead outward rather than remove it. Process equipment is wet-process packaging track hardware evaluated to SEMI S2 and SEMI S8, installed in ISO 14644-1:2015 Class 5/6 cleanrooms, with point-of-use filtration at 0.1 µm. The sequence is spin coat, top-edge rinse, backside solvent rinse, edge dry, soft bake or UV flood for dry-film resist, exposure, develop, then Cu plating or solder paste printing. For negative-tone dry-film resists, edge bead remover must be applied before final crosslink; after UV-cure or thermal imidization, edge residue cannot be redissolved by solvent alone and requires plasma ash. The deep technical constraint is that edge bead remover removal width must not exceed the die-edge keep-out, because solvent migrating under the edge bead can alter CD at the outermost bumps or RDL lines. Production lines qualify edge removal by dark-field inspection for residual flakes after develop and before plating. Terminal products are fan-out wafer-level packages, wafer-level chip-scale packages, copper pillar bumps, and RDL interposers.
| Segment | Substrate | Undiluted dispense / flow | Edge exclusion width | Observed failure boundary |
|---|---|---|---|---|
| 300 mm front-end IC | 300 mm Si | 0.6–2.0 mL per wafer | 1.0–3.0 mm | Resist flaking at etch when edge bead remains |
| Compound semiconductor | 150 mm GaAs, 200 mm SiC | 0.8–3.5 mL per wafer | 2.0–5.0 mm | Solvent wicking into active die edge if dwell > 10 s |
| Wafer-level packaging | 300 mm Si | 2–8 mL per wafer | 3.0–15.0 mm | Post-crosslink dry-film residue cannot be redissolved |
| MEMS/sensor | 150–200 mm Si | 0.5–2.0 mL per wafer | 1.5–6.0 mm | Hard-baked sacrificial resist edge cracking |
| Flat-panel display | Gen 8.5–10.5 glass | 10–80 mL/min per edge | 3–15 mm | Air-knife drying can drag dissolved resist into active area |
| Photomask/reticle | 6025 quartz | 0.2–0.8 mL per blank | 1.0–2.0 mm | Edge bead redeposition on chrome pattern write zone |
Because sacrificial photoresist layers in MEMS and sensor fabrication can reach 5–25 µm thickness and are later removed by solvent strip or oxygen plasma, edge bead control is inserted directly after spin coating to prevent cracked edge residues from elevating particulate levels above the deposition-chamber baseline. The edge bead remover is applied undiluted at 0.5–2.0 mL per 150 mm wafer, producing an edge exclusion width of 1.5–6.0 mm; the lower volume is set by the presence of through-wafer etch features that restrict the available top-side edge band. The process operates under ISO 14644-1:2015 Class 5 cleanroom conditions, with wet-process equipment evaluated under SEMI S2. After edge rinse, the resist-coated wafer is baked at 90–120°C, aligned, exposed, and developed; the cleared edge reduces particle transfer into deep reactive ion etching and vapour-phase HF release. If edge bead removal is omitted after thick-resist soft bake, microcracks at the wafer edge can propagate during wafer handling and generate particles above the chamber limit. Terminal products include silicon microphones, accelerometers, pressure sensors, gyroscopes, and microfluidic chips.
On Gen 8.5 and Gen 10.5 glass substrates used for TFT-LCD and OLED backplanes, edge bead removal is executed after slit coating by linear solvent extrusion along the coated edges, followed by an air knife that drags dissolved resist outward while preventing solvent flow into the display area. The edge bead remover is used undiluted and dispensed at 10–80 mL/min per edge, depending on substrate size and coat speed; the edge removal band is maintained between 3 mm and 15 mm. Compliance for this segment references SEMI S2 for wet-process equipment safety and ISO 14644-1:2015 Class 5/6 cleanroom operation. Downstream processing includes vacuum bake, exposure on large-area steppers or scanners, develop, etch, and stripping; the edge-cleared region prevents resist flakes from contaminating the photomask or the stage. Published point-of-use flow data for this specific configuration is limited; process owners qualify the setpoint by edge exclusion width inspection rather than nominal flow alone. Terminal products include amorphous-silicon TFT-LCD panels, LTPS mobile displays, OLED display backplanes, and mini-LED backplanes.
Photomask blanks in 6025 format are coated with resist on a chrome- or phase-shift-layer front side; edge bead removal is required before e-beam or laser write to eliminate particle sources and avoid stage contamination. Undiluted edge bead remover is dispensed at 0.2–0.8 mL per 6025 blank and controlled to an edge exclusion width of 1.0–2.0 mm, with the spin speed held at 200–500 rpm during the edge rinse step. The cleaning and coating environment is ISO 14644-1:2015 Class 4 or better, and the wet-processing hardware is evaluated under SEMI S2 and SEMI S8. After edge rinse, the blank is soft-baked, exposed by e-beam or laser, developed, and chrome-etched. Residual edge bead at the chrome interface can distort local etch rate and redeposit organic residue on the mask write zone; excessive edge bead remover below the edge band can lift resist at the blank edge and generate pattern fidelity loss. Terminal products include binary photomasks and phase-shift masks for DUV lithography.
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Edge Bead Remover (EBR) is a solvent system dispensed onto the periphery of a photoresist-coated wafer during spin coating to dissolve and remove the resist accumulation known as edge bead. The product described here, EBR-70/30, is a formulated blend of electronic-grade propylene glycol monomethyl ether (PGME) and propylene glycol monomethyl ether acetate (PGMEA) at a nominal mass ratio of 70:30. The blend is used on 200 mm and 300 mm coater tracks for positive-tone photoresists in i-line, KrF, and ArF processing. Its role is confined to edge-bead removal and backside edge rinsing; it is not a bulk photoresist stripper. The product acts by redissolving unexposed or pre-bake resist before crosslinking or thermal hardening. Because this step occurs before exposure and post-exposure bake, the solvent must dissolve the outer edge without disturbing the central resist film. That requirement imposes a narrow balance between solvency and evaporation. Low-viscosity, high-purity product with controlled water content is required to avoid particle generation and resist scumming. The EBR is filtered at point of use through 0.05 µm or 0.1 µm fluoropolymer filters and dispensed through low-pressure nitrogen-pressurized canisters. In production qualification, EBR-70/30 is compared with PGMEA-only and PGME-only edge-bead removers by edge-bead width uniformity, post-develop defect density, and metal contamination after spin-off.
On a closed coater-developer track, EBR-70/30 is dispensed through a moving nozzle positioned at a radial distance that defines the edge exclusion zone. Typical production settings fall within a spin speed of 800–1,500 min⁻¹, a dispense time of 0.5–2.0 s, and a flow rate of 20–60 mL/min. The nozzle tip is maintained 2–4 mm from the wafer surface to prevent splashing and to preserve a coherent low-pressure meniscus. Edge-bead removal width is controlled by the nozzle scan profile. A variation of more than ±0.2 mm in radial position is associated with incomplete removal or solvent penetration into active device areas. The wafer is spun after dispense for 3–5 s to dry the cleaned edge; excessive post-dispense spinning can reduce film thickness at the outer radii by centrifugal spread of residual solvent. Airflow and exhaust balance are critical because EBR evaporation from the dispense tip can produce a viscous film on the nozzle. If exhaust flow rate drops below the track minimum specification, solvent vapor accumulates over the wafer and can partially redissolve the top of the resist, creating a shallow crater or thickness loss outside the target edge bead. The process window is therefore quoted as spin speed ±100 min⁻¹, flow rate ±10 mL/min, and radial nozzle position ±0.2 mm. Outside this window, defect modes include edge-bead residues, lifted resist at the exclusion boundary, and backside contamination. Published data for specific resist stacks is limited; the values above represent common production tool recipes for chemically amplified positive-tone resist films with thicknesses between 0.5 µm and 1.5 µm.
Electronic-grade EBR-70/30 is controlled for water, metals, particles, and nonvolatile residue. Water is limited to ≤ 0.05 wt% by Karl Fischer titration using ASTM E203-24. Higher water content accelerates hydrolytic decomposition of PGMEA to PGME and acetic acid, which shifts the dissolution rate and can leave acidic residue on copper and aluminum bondpads. Metal contamination is controlled to low parts-per-billion levels, typically ≤ 50 ppb total metals by inductively coupled plasma mass spectrometry, because trace sodium, potassium, and iron degrade gate oxide integrity in front-end processing. Point-of-use filtration is performed with 0.05 µm or 0.1 µm PTFE or UHMWPE filters. Filter integrity is verified by bubble point or diffusion testing per manufacturer protocols. The product is not compatible with high-pressure diffusion filters that permit air ingress. Lines should be purged with dry nitrogen and protected from atmospheric moisture. The flash point of the blend is ≥ 31 °C by ASTM D56-22 closed-cup, which places it in the flammable liquid category. Dispensing must be performed in vented enclosures with interlocks for exhaust flow. Unattended storage of open containers in ambient air is not recommended at relative humidity above 60%. Equipment materials should be stainless steel or fluoropolymer; Buna-N and EPDM elastomers may swell or extract plasticizer and should be avoided in dispense lines. Viscosity is low enough for stable dispense through small-bore lines, typically below 2 mPa·s at 25 °C by ASTM D445-24.
For a typical i-line novolak/diazonaphthoquinone resist, the edge-bead removal step is performed immediately after spin coating and before softbake. A dispense arm moves to the wafer edge while the wafer rotates at low speed. The EBR dissolves the raised resist rim; the dissolved resist is slung outward and directed to the cup drain. The cleaned edge width is inspected after development with bright-field microscopy or automated macro-defect inspection. The process is considered acceptable when edge-bead residues are cleared within the specified exclusion zone and no solvent marks extend into the active die. The main failure mode on high-volume lines is incomplete removal at the wafer notch or flat due to local flow disturbance. Track hardware with a second backside rinse nozzle reduces backside contamination when the EBR is used on hydrophobic resists. In this configuration, the backside rinse nozzle dispenses a separate electronic-grade solvent at 10–30 mL/min during the edge-bead step, preventing redeposition of dissolved resist on the wafer backside. The cleaning endpoint is not easily measurable in situ; post-develop inspection by scanning electron microscopy is used to confirm no residual polymer at the edge. For low-viscosity resists, the EBR flow rate is reduced to the lower boundary of the dispense window to avoid capillary penetration into the active area.
On continuous production tracks, nozzle tip fouling and filter pressure rise are the primary causes of rate loss. The edge-bead removal rate is not directly measured; instead, wafer inspection after develop shows a recurrent edge-bead residue when the effective flow rate drops below 20 mL/min or when the nozzle meniscus is disturbed by exhaust imbalance. In such cases, the dispense system is purged with clean solvent, the nozzle tip is inspected for crystallized resist, and the point-of-use filter differential pressure is checked against the manufacturer maximum limit. A differential pressure above 0.10–0.15 MPa across a 0.05 µm filter indicates a fouled filter or inadequate filter wetting; replacement is required rather than increasing line pressure. Operators also inspect the dispense tip for dried PGMEA/PGME residues that form when elapsed time between wafers exceeds the solvent evaporation time at the tip. To avoid this, some tracks are configured with an idle purge at 0.2–0.5 mL/min or a solvent dip cup. Batch-to-batch variance in EBR water content can shift the edge-bead removal rate because water uptake during storage lowers the effective PGMEA concentration due to ester hydrolysis, producing acetic acid and increasing the polarity of the blend. This can cause over-wetting in the edge exclusion zone and larger edge-bead removal width than specified. For this reason, lot qualification includes water content and acidity checks. Lots with water above 0.05 wt% are rejected or dried by molecular sieve contact. The product must not be blended with amine-based additives or alkaline strippers because residual amines can contaminate chemically amplified photoresists and cause T-topping or footing.
PGME/PGMEA EBR-70/30 differs from single-solvent edge-bead removers in the balance between redissolution speed and drying time. PGME-only EBR has a higher relative evaporation rate and can dissolve the edge bead faster, but it may dry prematurely at the nozzle and has a lower solvency for some novolak resists. PGMEA-only EBR has a lower evaporation rate and longer drying time, which can leave residual solvent at the edge and widen the cleaned region if the post-dispense spin is too short. The 70:30 blend is selected to provide a distillation range of approximately 120–146 °C and a relative evaporation rate between the two single solvents. The table below gives characteristic physical comparisons for edge-bead removal solvents; the ranges are not product specifications but are used in track process screening.
| Property | EBR-70/30 | PGMEA-only EBR | PGME-only EBR | Ethyl lactate EBR |
|---|---|---|---|---|
| Principal solvent | PGME/PGMEA 70:30 | PGMEA ≥ 99.5% | PGME ≥ 99.5% | Ethyl lactate ≥ 99.5% |
| Density at 20 °C, g/cm³ (ASTM D4052-22) | 0.95–0.97 | 0.969 | 0.923 | 1.03 |
| Distillation range, °C | 120–146 | 145–146 | 119–121 | 151–154 |
| Closed-cup flash point, °C | 31–45 | 43–46 | 32–35 | 46–52 |
| Relative evaporation rate, n-butyl acetate = 1 | 0.45–0.55 | 0.34 | 0.62 | 0.28 |
| Typical edge-bead removal speed on novolak resist | Medium | Slow to medium | Fast, risk of drying | Slow, high wetting |
The table shows that PGME-only EBR has a low flash point and high evaporation rate, which increases fire risk and nozzle drying. Ethyl lactate EBR has a higher flash point and lower evaporation rate, but it may require a longer drying step and can leave a thin film if the wafer does not reach sufficient spin speed. EBR-70/30 is therefore used where a single solvent fails to clear the edge bead without spreading into the active pattern. This comparison is directional; specific resist compatibility must be verified by wafer-level defect density and post-develop SEM inspection.
Storage and distribution of EBR-70/30 in a bulk chemical room should use stainless steel pressure vessels or fluoropolymer-lined containers blanketed with dry nitrogen. The product is hygroscopic enough to absorb moisture through open vents, and the PGMEA ester can hydrolyze slowly in the presence of water and trace acid. The resulting acetic acid can corrode copper lines and shift developer pH if the solvent is drained into developer waste without segregation. A closed-loop dispense system with recirculation through a 0.05 µm filter is recommended to maintain particle cleanliness. Before first use, the entire dispense system is rinsed with the product and the rinse waste is collected for solvent disposal. The product is not formulated for direct immersion cleaning of wafer backsides with heavy organic contamination; that operation requires a separate backside cleaner or a hot solvent immersion step. It is also not designed for removal of fully crosslinked or deep-UV-exposed photoresist, and it does not strip implant-hardened resist or remove post-etch residues. When high-dose ion implantation is present, the resist crust is not dissolved by EBR; a downstream plasma or wet strip must be used. These limitations define the boundary between EBR as an edge-drying solvent and aggressive strippers.
The distinction between EBR, backside rinse, and bulk strip solvents is functional, not merely compositional. A backside rinse solvent is applied to the wafer backside to remove edge-bead overspray and particles; it is often PGMEA or a PGME/PGMEA blend similar to EBR. The difference lies in nozzle position, flow pattern, and process timing. EBR is applied to the top edge or edge exclusion zone; backside rinse is applied to the backside edge and may be dispensed simultaneously with EBR or in a separate step. A bulk strip solvent such as N-methyl-2-pyrrolidone, dimethyl sulfoxide, or a formulated alkaline stripper is used after processing to remove the entire photoresist film, including exposed and crosslinked regions. In contrast, EBR-70/30 is a low-temperature, short-contact solvent that is not heated and is not recycled through a stripper bath. Its contact time on the wafer is typically 1–3 s, whereas bulk strip immersion times range from 30 s to several minutes at elevated temperature. The EBR product is also controlled for low water and low particle content because it contacts only the edge of the resist film and does not undergo subsequent solvent purification before point of use. Using EBR as a bulk strip solvent would result in incomplete removal of crosslinked photoresist and excessive solvent consumption. Using bulk strip solvent at the edge-bead nozzle would contaminate the track with low-volatility residue and cause resist lifting far beyond the edge exclusion zone.
In a modern chemically amplified KrF process, the edge-bead removal module is often qualified by imaging the resist edge after develop and measuring the width of the removed zone with an overlay metrology tool. The process specification is derived from the device edge exclusion rules. For example, a product may require that no resist remain within 1.5 mm of the wafer edge and that no solvent penetration occur inward of 1.0 mm from the edge. EBR-70/30 is selected only after checking the compatibility of its PGME component with the resist solvent system. Some solvent-sensitive top coats require a lower PGME fraction or a different solvent blend. The user qualification sequence therefore includes a resist film thickness map after coating, edge-bead inspection after develop, optical defect scan with a laser-based inspection tool, and metal analysis of a blank silicon wafer after spin-off. A batch is released only when edge-bead residues are below the inspection threshold and no increase in post-develop defects is detected. This application-specific release prevents the use of a generic EBR product in a process where the edge removal zone is narrower than 1.0 mm. The required edge exclusion and the allowed solvent penetration are determined by the device design and the downstream etch or implant masks; published data for a specific device configuration is limited.
