| HS Code | 561881 |
| Product Name | Stripper (IC- Cu process) Electronic/EL Grade |
| Appearance | Colorless clear liquid |
| Chemical Family | Amine-based solvent formulation |
| Ph As Is | >12 (alkaline) |
| Specific Gravity At 25 C | 1.05 |
| Viscosity At 25 C Cp | 2.5 |
| Purity Assay | ≥99.9% |
| Metal Impurities Each | ≤1 ppb |
| Particle Count 0 2 µm | ≤100 particles/mL |
| Water Content | ≤0.1% |
| Boiling Point C | 160 |
| Flash Point C Closed Cup | >60 |
As an accredited Stripper (IC- Cu process) Electronic/EL Grade factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Packaged in clean, sealed 20L pails or 55-gallon drums; Electronic/EL grade stripper for IC-Cu process, ensuring purity. |
| Container Loading (20′ FCL) | Electronic/EL grade IC-Cu stripper is packed in sealed drums on pallets, securely loaded into a 20′ FCL container with proper hazmat labeling. |
| Shipping | Shipping restrictions apply: this electronic-grade copper stripper is corrosive and requires UN-compliant packaging, inert containers, and hazard labeling. Transport via ground freight only, in ventilated, leak-proof drums. Avoid moisture, heat, and incompatible materials. Include SDS, emergency response information, and proper hazardous materials documentation. |
| Storage | Store in a clean, tightly sealed original container in a cool, dry, well-ventilated area, ideally between 15–30°C. Protect from moisture, direct sunlight, and physical damage. Keep away from strong oxidizers, acids, and reactive metals. Avoid prolonged storage; use within manufacturer-recommended shelf life. Ensure secondary containment to prevent leaks and contamination. |
| Shelf Life | Shelf life is typically 6–12 months when stored unopened in original container at recommended temperature, away from heat, light, and moisture. |
On 200 mm and 300 mm copper pillar bump lines, EL-grade stripper for integrated circuit Cu processes operates in a bath-life-limited sequence after electrolytic pillar plating. Resist thickness from 40 µm to 120 µm is common, with positive-tone novolac systems used for aspect ratios above 1.0 and negative-tone acrylic dry films used for finer tip-to-tip spacing. The stripper bath receives acid copper plating carryover, so dissolved Cu²⁺ concentration rises across batch life and shifts free amine availability. In single-wafer spray processors, the working solution is dispensed at 1.2 L/min to 2.5 L/min per swing arm, with wafer rotation from 800 rpm to 1,500 rpm. Immersion batch tanks maintain 55 °C to 70 °C for 15 min to 35 min, depending on resist loading and bath age. The exposed copper pillar sidewall is passivated by benzotriazole or tolyltriazole at 0.05 wt% to 0.5 wt% in the working bath. DMSO or sulfolane swells the resist matrix, and alkaline hydrolysis cleaves the polymer backbone. Low-pressure DI water spray dislodges the fragmented film without reflowing organic residue. Post-strip inspection includes dark-field wafer inspection and ROSE testing per IPC-TM-650 2.3.25, with acceptance commonly above 1.0 × 10⁶ Ω·cm. The terminal output is a solder-capped copper pillar with tip diameter from 20 µm to 80 µm. An organic collar remaining on the pillar sidewall is a known cause of solder wetting failure under J-STD-002 conditions. The package is a flip-chip die ready for thermocompression bonding. Alkaline versions are not used on exposed aluminum bond pads because aluminum dissolves in strongly alkaline media. Cu-specific benzotriazole inhibition does not protect aluminum. Site-specific bath-life limits are set by ICP-MS copper loading and pillar sidewall pitting coupons rather than by fixed cycle counts.
After electrolytic Cu pattern plating in SAP and mSAP substrate fabrication, the limiting defect after dry film strip is undercut and line collapse at trace spacing below 10 µm. Dry film resist in the 10 µm to 25 µm thickness range is removed from Cu traces without dissolving the underlying seed layer. Alkaline baths with pH above 10.5 can raise the Cu etch rate above 1.0 nm/min if the benzotriazole film is disturbed by cavitation. Megasonic rinse at 0.8 MHz to 1.2 MHz is therefore preferred over 40 kHz ultrasonic tanks. Acoustic streaming dislodges swollen resist fragments without cavitation-induced seed-layer pitting. The working bath contains a polar aprotic solvent such as DMSO or sulfolane for dry film swelling and a quaternary ammonium hydroxide or alkanolamine for ester crosslink cleavage. Temperature is held between 50 °C and 60 °C rather than 70 °C, because panel warpage on 510 mm × 610 mm ABF substrates increases with temperature differential across patterned copper. A 30 s to 60 s CO₂-bubbled DI water rinse after chemical strip rebuilds a stable oxide interface before acid clean. The terminal product is an FCBGA substrate with 2/2 µm or 5/5 µm line/space traces that must survive open/short testing and die-attach lamination without residue-induced delamination. Ionic contamination is measured by ROSE per IPC-TM-650 2.3.25. Acceptance for high-density substrates is often set at ≤0.5 µg NaCl equivalent per cm², though published site-specific limits vary. The dominant process control variable is the ratio of free amine to inhibitor. Automatic titration is used because resist loading shifts this ratio as the bath ages. At 2/2 µm geometry and below, published line-collapse data is limited, and rinse-and-dry module configuration rather than stripper chemistry often becomes the controlling factor.
Panel-scale processing for fan-out redistribution layers has a lower tolerance for amine-water stripper formulations than wafer-level tools because exposed copper pad surface area per panel can exceed 0.5 m². Removal of a 15 µm to 30 µm dry film after RDL Cu plating is performed in conveyorized spray chambers or vertical dip tanks with automatic transfer. A solvent-rich first stage swells the film, an aqueous alkaline second stage hydrolyzes the binder, and a high-pressure DI rinse at 1.0 MPa to 2.0 MPa removes residue from the seed layer. The copper surface must retain an inhibitor film that survives both alkaline strip and subsequent acid seed etch. If the inhibitor is too weak, pitting appears at the triple junction between RDL line bottom, seed layer, and polymer passivation. If the inhibitor is too strong, seed etch requires higher acid concentration and line undercut risk increases. Published comparative etch-rate data for panel tools with nozzle arrays above 600 mm × 600 mm is limited. Coupon-level response curves are used to define the working bath. The terminal product is a multi-chip fan-out wafer or panel with Cu RDL line width from 5 µm to 15 µm, ready for dielectric curing and micro-bump attach. In-line inspection uses automated optical inspection with 2 µm resolution. Residual organic contamination on Cu pads is confirmed by TOF-SIMS or XPS, with acceptance commonly below 5 atomic % carbon after argon sputter. Particle monitors track post-rinse defect density at ≤0.05 defects/cm² for pad-level cleanliness, and bath replenishment is conductivity-based.
| Compliance dimension | Standard or method | Cu process target range |
|---|---|---|
| Ionic surface cleanliness after strip | IPC-TM-650 2.3.25 ROSE | ≥1.0 × 10⁶ Ω·cm or ≤0.5 µg NaCl/cm² where specified |
| Wetted component compatibility | SEMI F57-0301 | No Fe, Cr, Ni extraction above detection limit at process temperature |
| Final strip and rinse cleanroom environment | ISO 14644-1:2015 | Class 5 or better in critical rinse modules |
| Restricted solvent content in EU supply chain | REACH Regulation (EC) No 1907/2006 Annex XVII | NMP below restriction threshold; alternative DMSO or sulfolane preferred |
| Heavy metal restrictions | RoHS Directive 2011/65/EU Annex II | Pb < 1000 ppm homogeneous, Cd < 100 ppm homogeneous |
In through-silicon via flows with via diameter from 10 µm to 50 µm and aspect ratio up to 10:1, the stripper must enter high-aspect-ratio recesses where mass-transfer limitations control the rate. Bulk bath agitation does not scale to the bottom of a 50 µm deep via. A solvent-rich formulation with reduced viscosity is needed for full via wetting, followed by a low-concentration alkaline hydrolysis step to avoid sidewall copper roughening. The Cu sidewall inside the via is passivated with a thin cuprous oxide–benzotriazole complex. This layer must remain intact through the subsequent rinse and drying sequence. In batch immersion, the process is often run at 25 °C to 40 °C for 20 min to 40 min, with slow wafer lifting to allow polymer fragments to exit the via without re-deposition. Equipment selection includes quartz or PTFE-lined tanks because DMSO-based strippers can extract iron, chromium, and nickel from stainless steel surfaces at elevated temperature. All wetted polymer components are specified to SEMI F57-0301. Post-strip via cleanliness is verified by top-down SEM at 45° tilt and cross-section FIB, with acceptance requiring no continuous organic layer thicker than 1 nm on the via bottom. The terminal product is a thinned TSV wafer with Cu nails ready for backside passivation and RDL build. Thermal control is critical because copper etch rate in aggressive amine formulations increases nonlinearly above 45 °C. In high-volume lines, the strip bath is controlled to ±2 °C to maintain via critical dimension. The EL-grade stripper must not be blended with acid peroxide seed etch chemistries or strong oxidizers. Exothermic decomposition and rapid Cu attack can occur in mixed waste lines.
The sequence of resist strip followed by Cu seed etch places two competing demands on the EL-grade stripper. After dry film removal from RDL copper lines, a thin Cu seed layer remains on field areas and must be etched in a dilute acid or cupric chloride solution. The stripper must not leave an inhibitor film that suppresses seed etch rate below the line throughput requirement, yet the RDL copper surface must remain free of pitting during alkaline strip. A controlled inhibitor desorption step is introduced by a 30 s to 60 s DI water rinse at pH 6.5 to 7.5 with dissolved CO₂. This weakens the benzotriazole film predictably. A pure hot DI rinse produces variable seed etch induction times. High-density fan-out packages with RDL line width of 5 µm to 10 µm use spray cleaning tools with oscillation arms and barrier-free transfer to prevent particle re-adhesion after strip. The terminal product is a reconstructed wafer with Cu RDL lines and micro-bump pads ready for under-bump metallurgy deposition. Batch-to-batch variation is controlled by near-infrared moisture analysis of the dry film before coating and by automatic titration of free amine content in the working bath. If titrated free amine drops below the formulation lower limit, strip time must be extended or the bath renewed. Operating beyond the upper limit causes copper seed layer attack and line lifting.
In quad-flat no-leads and exposed-pad packages, electrolytic Cu bump plating on copper leadframes uses a photoresist mask that must be removed before wire bonding and mold compound transfer. The stripper bath is an aqueous-organic alkaline system running at 60 °C to 75 °C in a spray-and-flood cell. This temperature band swells plated resist that is thinner than wafer-level films at 10 µm to 20 µm. The exposed Cu leadframe surface is prone to galvanic attack at the interface with silver spot plating applied before bump formation. The inhibitor package must suppress Cu dissolution without depositing a residue that reduces silver wire-bond pull strength. Post-strip cleaning includes DI water cascade rinsing and hot air drying. Ionic contamination after strip is checked by ROSE per IPC-TM-650 2.3.25, with acceptance commonly ≤0.75 µg NaCl equivalent per cm² for leadframe surfaces. The terminal product is a QFN strip with plated Cu bumps, intact silver spots, and low residual chloride, ready for die attach. Process engineers limit dissolved metal loading in the bath to below 500 ppm for Cu and below 50 ppm for Ag. Above these levels, redeposition or silver sulfide staining risk increases. The bath is filtered through 1 µm polypropylene cartridges and maintained by conductivity-based replenishment.
Competitive Stripper (IC- Cu process) Electronic/EL Grade 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!
Stripper (IC-Cu process) Electronic/EL Grade is an alkaline liquid resist stripper supplied for post-ash residue and photoresist removal on copper damascene, Cu redistribution layer (RDL), Cu pillar bump, and through-silicon via structures. The product designation identifies the material as Electronic/EL Grade, a classification that imposes reduced trace-metal and particle burdens relative to technical-grade strippers. The product is intended for use in single-wafer spray processors and recirculated immersion tanks. The formulation removes positive-tone DNQ/novolac and chemically amplified deep-UV resists after plasma ashing while preserving Cu, TiN, TaN, and low-k dielectric film integrity. The product is supplied as a ready-to-use liquid; no dilution is required for standard Cu back-end-of-line applications. The model designation is carried in the full product name; the manufacturer does not assign an additional numeric suffix.
Release specifications for the product include a pH of 10.8–11.8 at 25 °C, density of 1.06–1.12 g/cm³, and dynamic viscosity of 2.8–4.2 cP at 25 °C. Electronic/EL Grade control limits for critical cations are ≤10 ppb per element for Na, K, Ca, Mg, Fe, Cr, Ni, Cu, and Zn when measured by inductively coupled plasma mass spectrometry. Particle count is ≤10 particles/mL at the 0.1 μm threshold using liquid optical particle counting. Anion contamination for chloride, nitrate, and sulfate is ≤10 ppb each. The product is filtered through 0.05 μm final membrane filtration prior to packaging. Flash point is typically greater than 100 °C because the continuous phase is predominantly water.
| Parameter | Typical criterion | Method designation |
|---|---|---|
| Critical cation contamination | ≤10 ppb each for Na, K, Ca, Mg, Fe, Cr, Ni, Cu, Zn | ASTM D5673-16 |
| Anion contamination | ≤10 ppb for Cl⁻, NO₃⁻, SO₄²⁻ | ASTM D4327-17 |
| Particle count | ≤10 counts/mL at 0.1 μm | ISO 21501-2:2019 |
| pH | 10.8–11.8 | ASTM E70-19 |
| Dynamic viscosity | 2.8–4.2 cP | ASTM D445-21 |
Process control parameters are derived from blanketed Cu film etch-rate coupons rather than from fixed immersion time alone. The stripper is operated at 50–70 °C in immersion tanks and 40–65 °C in single-wafer spray tools. At bath temperatures above 75 °C, the Cu dissolution rate increases and the azole passivation film becomes less stable, leading to roughening of the Cu seed layer. Bath pH is maintained in the 10.8–11.8 range; excursions above 12.0 increase galvanic attack at Cu/TiN interfaces. Carbon dioxide absorption from ambient air reduces pH and can produce carbonate precipitation, which is controlled by nitrogen blanketing or sealed tank covers.
Residue types encountered in Cu back-end-of-line processing include fluorinated polymer from CF4/O2 ash, metal oxide sidewall residues, and stubborn photoresist after high-dose ion implantation. The stripper contains a high-boiling solvent blend that swells the cross-linked resist crust and an alkaline component that hydrolyzes ester linkages in the resist polymer. Removal of ion-implanted photoresist with a dose of 1×10¹⁵ ions/cm² or higher typically requires a first immersion at 60 °C for 10–15 min, followed by ultrasonic agitation at 40 kHz. For heavily implanted resist, a two-bath sequence is recommended: the first bath performs bulk removal, and the second bath removes residual carbon. Bath loading is measured by total organic carbon; replacement is required when TOC exceeds 40 ppm to maintain consistent strip rate.
In production-scale 200 mm and 300 mm batch tools, bath life is commonly extended by continuous filtration through 0.1 μm PTFE membranes and by replenishment of evaporated aqueous phase. Differential pressure across the point-of-use filter is held below 1.5 bar to prevent particle shedding. Bath copper concentration is monitored by ICP-MS; bath replacement is triggered when Cu concentration exceeds 50 ppm or when strip time for a fixed resist load exceeds 2× the fresh-bath value.
The stripper is operated within a narrow temperature and pH window because Cu corrosion is governed by both electrochemical potential and inhibitor desorption. On production-scale single-wafer spray tools, the dispense temperature is maintained at 60 °C for the first dispense and 55 °C for the second dispense, with flow rates of 1.0–2.0 L/min. In batch immersion systems, temperature control at ±2 °C is required to prevent non-uniform residue removal across the wafer cassette. Wetted components in the strip chamber are specified as PTFE, PVDF, quartz, or high-purity polypropylene. Prolonged contact with unpassivated stainless steel is not recommended because alkaline amine components can leach iron and raise particle counts above the electronic grade limit.
Compatibility with aluminum interconnects is limited; this product is intended for Cu-process flows. If Al bond pads are present on the wafer, a chloride-free rinse and short contact time below 60 °C are required because alkaline strippers can etch aluminum and produce pitting when chloride contamination exceeds 10 ppm.
Rinsing after the strip step uses ultrapure water with resistivity ≥18.2 MΩ·cm at 25 °C. A two-stage overflow rinse of 180–300 s per stage removes residual stripper and prevents redeposition of dissolved resist organics. In single-wafer spray tools, the rinse sequence may include a dilute CO₂-sparged water step at 1–2 L/min to reduce pH shock on Cu surfaces before final ultrapure water rinse. Wetted parts in the rinse module are specified as PTFE, PVDF, quartz, or high-purity polypropylene; no metallic contact is permitted downstream of the final strip chamber.
Residue removal performance is evaluated on patterned Cu/low-k wafers after CF4/O2 plasma ashing. The stripper removes sidewall polymer and fluorinated residues without increasing the dielectric constant of porous SiCOH films. Mercury-probe capacitance–voltage measurements after stripping show no flatband voltage shift greater than 0.2 V when the process is operated within the stated temperature window. The low etch rate on Cu is confirmed by four-point probe sheet-resistance mapping; an increase in sheet resistance of ≤0.5% is considered acceptable for 200 mm and 300 mm production wafers.
For Cu pillar bump wafers, the strip time is shorter than for blanket Cu test coupons because the exposed Cu area is lower and the resist thickness on pillar tops is higher. Segmented spray recipes are used with a first dispense at 60 °C for 120 s, a second dispense at 55 °C for 90 s, and a rinse step at 1.5 L/min. The product removes resist from via sidewalls without producing measurable undercut at the Cu/TiN interface when inspected by cross-section scanning electron microscopy.
Relative to NMP-based strippers, the product does not contain N-methyl-2-pyrrolidone, which is subject to restricted-use documentation under REACH Annex XVII. The vapor pressure is lower than that of typical solvent blends, reducing bake-out residue on chamber walls and improving operator exposure margins. Compared with hydroxylamine-based Cu strippers, the formulation employs an azole inhibitor package that lowers Cu etch rate to ≤2 Å/min at 60 °C in static coupon tests while maintaining residue removal on high-dose ion-implanted photoresist. However, the product is not recommended for removal of fully cured polyimide or silicone passivation because alkaline hydrolysis of those films is slower than in aggressive solvent blends.
Another operational difference is purity. General-purpose strippers may carry 100–500 ppb total metal contamination, while Electronic/EL Grade material is controlled to ≤10 ppb per critical cation, reducing the risk of mobile ion contamination in Cu/low-k dielectrics. The product is also filtered at point of use through 0.05 μm membranes; combinations with unfiltered solvent strippers can introduce particles that lower probe yield. In addition, the product avoids halogenated solvent components, therefore it is not managed as a hazardous air pollutant under the United States Clean Air Act solvent category.
Corrosion inhibition is provided by a benzotriazole-type adsorption layer. The inhibitor chemisorbs onto Cu(111) and Cu(200) surfaces and reduces the anodic corrosion current in alkaline cleaning environments. Potentiodynamic polarization measurements using a three-electrode cell with a saturated calomel reference electrode per ASTM G5-14e1 show open-circuit potential shifts of −0.25 V to −0.15 V vs SCE for treated Cu in the bath. The passivation film is removed by the subsequent rinse and is not intended to remain on the Cu surface after drying. In-line X-ray photoelectron spectroscopy of processed wafers shows no detectable increase in C–N or N–H surface species after rinse, indicating the inhibitor does not leave a persistent organic residue. Published data for this specific formulation are limited; the stated ranges represent typical Cu-compatible stripper behavior reported across semiconductor chemical supplier technical bulletins.
Spent stripper solutions contain dissolved copper, organic amines, and resist byproducts. Waste treatment includes pH adjustment to 9–10 with sulfuric acid, precipitation of copper as hydroxide/oxide, and separation through filter press or membrane filtration. Copper concentration in discharged aqueous effluent is controlled to local limits, commonly ≤1 ppm in semiconductor fabs. The product is supplied with safety data sheets in accordance with REACH Article 31 and 29 CFR 1910.1200. No CMR category 1A/1B substances are intentionally added. The stripper should not be blended with hydrogen peroxide or strong oxidizers because exothermic decomposition may occur; mixing with acidic post-etch residue removers in the same tank is also prohibited because acid-base neutralization can precipitate organic solids.
Storage of unopened containers is recommended at 15–30 °C, away from direct sunlight and acids. Shelf life is typically 12 months from date of manufacture when stored in original fluoropolymer-lined containers. Once opened, the material should be blanketed with nitrogen and used within 72 h to prevent carbonate absorption. Lot-to-lot variation in pH and viscosity is controlled within the release criteria listed above; no additional filtration is required before use.
