| HS Code | 607318 |
| Product Type | Negative-acting photoresist dry film |
| Grade | Electronic/EL Grade |
| Functional Use | High-resolution imaging for printed circuit board and electronic laminate processing |
| Resist Form | Dry film supplied on a polyester support with a polyethylene release layer |
| Visible Color | Blue |
| Potential Film Thickness Options | Available in nominal coating thicknesses from approximately 20 to 35 micrometers |
| Photoreactive Wavelength Range | Near-ultraviolet region, approximately 350 to 410 nm |
| Exposure Response | Negative working, requiring actinic UV exposure to polymerize exposed areas |
| Aqueous Development Behavior | Developable in dilute sodium carbonate solution |
| Stripping Behavior | Removable by sodium hydroxide-based aqueous stripper |
| Adhesion Characteristic | Strong adhesion to copper surfaces to support fine-pattern definition |
| Resolution Capability | Capable of forming fine lines and spaces down to approximately 25 micrometers under controlled conditions |
| Plating Resistance | Resists solder plating, copper electrolytic plating, and standard acid etchants |
| Etch Resistance | Withstands acid and alkaline copper etch processes |
| Storage Condition | Store in a cool, dark, clean environment below 25°C in original packaging |
| Nominal Shelf Life | Typically 6 months from the date of manufacture under recommended storage conditions |
As an accredited Photosensitive Dry Film (Asahi Kasei Apex 2000) Electronic/EL Grade factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Packaged as sealed light-proof rolls, moisture-barrier bags with desiccant, in quantities of one roll per carton, for Electronic/EL Grade use. |
| Container Loading (20′ FCL) | Load 20' FCL with cartons on pallets, secure tightly, keep dry, avoid pressure, and ensure no sharp objects damage film. |
| Shipping | This photosensitive dry film must be shipped in light-tight, moisture-resistant packaging to prevent premature polymerization. Keep cool (below 25°C) and away from UV radiation. Handle with care to avoid physical damage and static discharge. Ensure compliance with applicable transport regulations, labeling as non-hazardous but sensitive to light and heat. |
| Storage | Store Photosensitive Dry Film (Asahi Kasei Apex 2000) in a cool, dry, dark environment at 5–25°C in its sealed, light-tight original packaging. Protect from sunlight, UV, X-rays, moisture, heat, and strong oxidizers. Avoid physical damage and bending. Keep inventory rotated; use before expiration date to ensure optimal performance. |
| Shelf Life | Shelf life is typically 6 months from manufacture when stored upright in a cool, dark, dry environment. |
In HDI outerlayer patterning on 18 µm electrodeposited copper foil, the Asahi Kasei Apex 2000 Electronic/EL Grade dry film is laminated at roll temperatures between 100 °C and 110 °C. Hot-roll lamination equipment with 300 mm diameter silicone rubber rollers is operated at speeds from 1.0 m/min to 1.8 m/min. Nip pressure is maintained between 0.4 MPa and 0.6 MPa. Vacuum lamination is selected when copper surface roughness exceeds 5 µm Rz because entrapped air at the resist-copper interface produces post-exposure tenting defects. The film is conditioned for 15 min to 30 min at 22 °C to 25 °C before direct imaging. Laser direct imaging at 405 nm requires an exposure dose between 30 mJ/cm² and 80 mJ/cm² for feature classes from 25 µm/25 µm to 50 µm/50 µm. Development in a double-sided spray chamber uses 1.0 wt% Na₂CO₃ at 28 °C to 32 °C. The development breakpoint is controlled at 40% to 60% of chamber length. Developer spray pressure is held between 1.2 kg/cm² and 2.0 kg/cm² for 25 µm lines. Post-development rinse water is kept below 35 °C to prevent carbonate residue redeposition. Cupric chloride etching is performed at 48 °C to 52 °C with 2.0 mol/L HCl. Undercut for 25 µm features must not exceed 8 µm per side. Resist stripping in 3 wt% NaOH at 45 °C to 55 °C is assisted by 40 kHz ultrasonic agitation. Adhesion is verified per IPC-TM-650 method 2.4.28.1. Etched line width is inspected by automated optical inspection to IPC-6012 Class 3 limits.
| Feature class | Exposure dose | Development breakpoint | Developer pressure | Maximum undercut per side | Qualification method |
|---|---|---|---|---|---|
| 25 µm/25 µm | 60–80 mJ/cm² | 40–50% | 1.8–2.0 kg/cm² | ≤8 µm | IPC-6012 Class 3 |
| 35 µm/35 µm | 45–65 mJ/cm² | 45–55% | 1.5–1.8 kg/cm² | ≤6 µm | IPC-6012 Class 3 |
| 50 µm/50 µm | 30–45 mJ/cm² | 50–60% | 1.2–1.5 kg/cm² | ≤5 µm | IPC-6012 Class 2 |
Photochemical machining of 304 stainless steel and C17200 beryllium copper foil uses the dry film as a continuous etch mask over sheet thicknesses from 50 µm to 300 µm. The resist is applied in a cut-sheet hot-roll laminator with roller hardness Shore A 85 and surface temperature 105 °C ± 5 °C. The central process conflict in this application is the relationship between spray-out pressure and resist adhesion. Production-scale etchers with oscillating spray bars running at 2.0 kg/cm² to 3.5 kg/cm² generate etch factor values between 1.8 and 2.4 on 304 stainless steel, while operation at 1.0 kg/cm² reduces etch factor to below 1.5. The same increase in pressure introduces hydrodynamic shear at feature edges, and partial resist lifting occurs when the breakpoint exceeds 65%. Ferric chloride etchant is maintained at 45 °C to 55 °C with Baumé gravity 42 °Bé to 48 °Bé. The dry film must maintain adhesion under continuous impingement for 8 min to 20 min depending on foil thickness. Pre-etch adhesion is qualified by ASTM D3359-17 cross-cut tape pull with a classification of 5B after lamination. Developed feature resolution is measured on a vision measuring machine with ±2 µm repeatability. Terminal components include encoder discs with 20 µm slot widths, surface-mount stencil blanks, and aperture masks for high-density interconnection test fixtures. For stainless steel foil with thickness 100 µm, the minimum slot width is controlled at 1.2× material thickness. This geometric rule prevents the etch front from merging at the center of the slot when spray pressure is above 2.5 kg/cm².
Selective plating of QFN and SOIC leadframes uses the dry film as a stop-off mask on stamped or etched Alloy 42 and C194 copper alloy strips. Lamination temperature is reduced to 95 °C to 105 °C because Alloy 42 stress relaxation becomes measurable above 110 °C. The film is exposed through a glass phototool with alignment tolerance ±10 µm. Development opens pad windows in the unexposed areas and produces a sidewall angle that must be steeper than 80° to prevent electrolytic plating bleed. Electrolytic Ag plating is run at current densities from 2.0 ASD to 6.0 ASD in a non-cyanide bath at 60 °C and pH 8.8 to 9.2. For Ni/Pd/Au leadframe finishes, the resist must withstand sulfamate nickel plating at pH 4.0 to 4.5 and 55 °C, followed by palladium and gold flash steps. Stripping after selective plating is performed in 5 wt% NaOH containing 1.5% monoethanolamine at 55 °C; this alkaline formulation removes residues that pure sodium hydroxide leaves after Pd bath exposure. The electronic/EL grade requirement is evaluated by ion chromatography after aqueous extraction, with total ionic contamination below 1.6 µg/cm² NaCl equivalent according to IPC-TM-650 method 2.3.25. Terminal products include QFN packages with 0.4 mm pitch pads and SOIC leadframes with selectively plated Ag spots. In production runs, the dominant failure mode is not resist lifting but plating bleed caused by over-development; breakpoint above 60% is therefore rejected by in-line optical inspection.
Wafer-level under-bump metallization uses the dry film as a plating mold with uniform thickness across 200 mm and 300 mm wafers. The film is laminated in a vacuum laminator at a platen temperature of 110 °C and a vacuum level below 5 kPa. Vacuum lamination is required to eliminate air voids around probe pad topography. For Cu/Ni/Au UBM stacks with plated heights from 8 µm to 25 µm, the dry film thickness must exceed the target plated height by at least 5 µm. Exposure through a glass mask with 365 nm collimated UV is set between 80 mJ/cm² and 150 mJ/cm² to create sidewalls suitable for bump pitch from 150 µm to 400 µm. Development uses 1.0 wt% Na₂CO₃ at a spray pressure of 1.5 kg/cm², with breakpoint terminated at 50% to maintain via bottom cleanliness. Cu electroplating from acid sulfate proceeds at 3.0 ASD; the film must tolerate the bath’s sulfuric acid concentration of 180 g/L to 220 g/L for 45 min to 120 min. The limitation in this configuration is throughput. Vacuum lamination adds 2 min to 4 min per wafer compared to spin-coated liquid resist, and is therefore only justified for bumped wafers with high value density. Resist pads below 100 µm diameter show adhesion failures when the dehydration bake is omitted. Published data for this specific configuration is limited; in practice, sidewall angle and adhesion are established by cross-sectioning a pilot wafer rather than relying solely on nominal exposure tables. Bump shear acceptance follows JEDEC JESD22-B117. After plating, the film is stripped in a two-step sequence: organic solvent pre-swell followed by 3 wt% NaOH at 50 °C. Terminal products include bumped CMOS wafers and MEMS carrier wafers with electroformed Cu pillars.
Electroforming of high-tension nickel stencils uses the dry film as a sacrificial plating mold on passivated stainless steel mandrels. The mandrel surface is passivated with a chromium oxide layer to reduce resist adhesion and permit clean stripping after nickel plating. Lamination is carried out at 105 °C with nip pressure 0.35 MPa. For stencil thicknesses from 50 µm to 150 µm, the dry film stack thickness is selected between 40 µm and 160 µm. Sulfamate nickel electroforming is run at 55 °C and 2.0 ASD to 4.0 ASD with pH 3.8 to 4.2. The plating current density is kept below 4.0 ASD because higher current density increases tensile stress in the nickel deposit and produces resist cracking at the base. Resist sidewall angle after development is controlled to 80° to 85° to provide release draft. After electroforming, the dry film is stripped in 4 wt% NaOH at 50 °C. The resulting nickel apertures have trapezoidal cross-sections. Minimum aperture width for a 100 µm nickel stencil is 80 µm. Surface roughness of the nickel sidewalls is checked according to ISO 4287 with Ra below 0.8 µm. Terminal products include SMT stencil foils and fine-pitch wafer-bumping stencils with aperture position accuracy better than ±5 µm per IPC-7525.
Roll-to-roll lamination of the dry film on 25 µm polyimide with 18 µm rolled annealed copper is performed at 100 °C to 110 °C and 0.3 MPa to 0.5 MPa. The film must tent through-holes with diameters between 0.2 mm and 0.5 mm without rupture. Plasma pretreatment with Ar/O₂ at 200 W for 30 s increases polyimide surface energy from 38 mN/m to 52 mN/m. Exposure energy is reduced by 15% when a nitrogen-purged contact frame is used because oxygen inhibition at the film surface lowers photo speed. Development uses 1.0 wt% Na₂CO₃ at 30 °C; tenting reliability is checked under a 0.2 MPa water rinse. Alkaline cupric chloride etching of rolled annealed copper at 50 °C produces line width loss below 10 µm for 50 µm features. The operational boundary appears at via densities above 60 holes/cm²; below this density, tenting failure is below 0.5% in production lots. Resist stripping is performed in 3 wt% NaOH at 45 °C. Tape adhesion testing follows IPC-TM-650 method 2.4.28.1. Terminal products include two-layer flex circuits for camera modules and hinge flexures, qualified to IPC-6013 Class 3.
When indium tin oxide replaces electrodeposited copper as the conductive layer, the etch chemistry shifts from cupric chloride to halogen or organic acid systems. The dry film is laminated at 95 °C because PET substrates distort above 120 °C. A dehydration bake at 80 °C for 10 min is used before lamination to improve adhesion to ITO. The ITO etchant is either oxalic acid at 45 °C or hydrochloric acid with ferric chloride, depending on sheet resistance. The film must withstand pH below 1.0 for 60 s to 120 s. Exposure dose is increased to 80 mJ/cm² to 120 mJ/cm² because UV scattering at the ITO surface reduces line edge sharpness. Development uses 0.8 wt% Na₂CO₃ at 28 °C to prevent attack on the underlying ITO. Fine-line capability is limited to 30 µm lines because ITO etch undercut is higher than copper; the etch factor for ITO in HCl/FeCl₃ is typically 1.2 to 1.5. Adhesion is qualified by ASTM D3359-17 with tape pull classification 4B minimum. After stripping, the substrate is rinsed with deionized water below 1.0 µS/cm conductivity. Residual sodium carbonate must be below 0.1 µg/cm² to avoid luminous non-uniformity in EL devices. Terminal products include electroluminescent lamp electrodes, touch sensor grids, and OLED test coupons.
On 96% alumina substrates, thick-film conductor patterning for LTCC and precision chip resistors uses the dry film as an etch mask over screen-printed gold or copper. The fired conductor thickness ranges from 5 µm to 12 µm. The film is laminated at 100 °C and 0.4 MPa; vacuum lamination is used when the screen-printed conductor has edge roughness above 3 µm. Gold conductors are etched with iodine/potassium iodide solution at 45 °C, while copper conductors are etched with cupric chloride at 50 °C. The dry film must withstand the iodine-based etchant for 90 s to 150 s without lifting. Minimum conductor width is 50 µm for gold and 75 µm for copper because of etch undercut differences. After etching, the film is stripped in 3 wt% NaOH at 45 °C. The electronic/EL grade low-extractable ionic profile is relevant for chip resistor terminations; residual potassium from the gold etchant is controlled below 0.5 µg/cm² after rinsing with deionized water above 18 MΩ·cm. Adhesion is verified per ASTM D3359-17 with 5B classification. Terminal products include LTCC RF modules, precision chip resistor arrays, and ceramic sensor heater patterns.
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Asahi Kasei Apex 2000 is a negative-acting, aqueous-processable photosensitive dry film supplied as a polyethylene-protected roll for electronic interconnect fabrication. The Electronic/EL grade indicates a formulation intended for printed circuit board and electroless metallization sequences where controlled ionic contamination and residue extractables after development are design requirements. The film is applied by heat and pressure lamination onto oxide-treated copper-clad laminates, exposed with 365–405 nm actinic radiation, developed in dilute aqueous sodium carbonate, and stripped after pattern plating or etch processing. It is produced in nominal thicknesses of 15 µm, 20 µm, 25 µm, 30 µm, 40 µm, and 50 µm, with a cross-web thickness tolerance commonly controlled to ±2 µm. The dry film contains a photopolymerizable acrylic monomer system dispersed in a thermoplastic binder with a radical photoinitiator. Exposed regions crosslink and become insoluble in the alkaline developer; unexposed regions are removed in the developing bath. Because the product is aqueous-processable, it does not require organic developer solvents, thereby reducing volatile organic compound loading in the development area. The material is sensitive to ambient ultraviolet light and must be handled under yellow or amber safelight conditions. Its primary functions include acid copper pattern plating, etch resist, and tenting over plated through holes. Unlike liquid photoresists, Apex 2000 provides a dry, uniform thickness pre-formed layer that avoids edge bead and solvent evaporation variability on panel surfaces. Users should confirm lot-specific sensitometric data with the manufacturer because sensitivity and contrast vary slightly with coating thickness and dye concentration. The grade is not intended for direct soldermask application or for use with amine-based solder mask developers that can attack the resist surface. The product’s alkaline strippability allows removal in hot sodium hydroxide solutions after plating, but strip residue must be filtered to avoid re-deposition of resist particles. In high-volume printed circuit board fabrication, the film is integrated with automatic laminators, conveyorized developers, and direct imaging equipment. These process interactions determine final yield more than the resist chemistry alone.
The resist layer is based on a photopolymerizable acrylic monomer system dispersed in a thermoplastic binder. The photochemical contrast between exposed and unexposed regions is governed by the initiator absorption profile and by oxygen inhibition at the film surface. Processors using collimated exposure units with vacuum drawdown achieve better sidewall geometry than those using non-collimated sources. The film’s optical density after exposure is sufficient for automated optical inspection units, though dye content is lot-controlled. In direct imaging systems, the photo-tool is eliminated, and step-and-repeat alignment can be corrected for panel distortion. The exposure energy required for direct imaging may be higher because of multiple low-dose passes; typical cumulative doses remain in the 35–60 mJ/cm² range at 405 nm.
Resolution capability is a system response influenced by exposure energy, collimation half-angle, photo-tool contact, substrate reflectivity, developer endpoint, and post-exposure hold time. For 25 µm line-and-space work on copper, the practical exposure dose at the resist surface is 35–60 mJ/cm². Dose levels below 30 mJ/cm² typically produce undercut and poor adhesion; dose levels above 65 mJ/cm² create photopolymer bloom and widening of fine lines. On bright copper substrates, reflected energy increases the effective dose at the resist base, narrowing the usable exposure window to approximately ±5 mJ/cm². Exposure systems with a collimation half-angle greater than 5° degrade sidewall geometry and linewidth uniformity. Development is performed in 0.8–1.2 wt% sodium carbonate at 28–32°C, with a spray chamber breakpoint of 45–90 s. Operating the developer beyond 150% of breakpoint promotes foot formation and loss of fine-line adhesion. Adhesion after development is commonly checked by tape pull according to IPC-TM-650 2.4.28.1, with no removal of resist from the test pattern required for qualification. The exposed resist film is also inspected under automated optical inspection before etching or plating.
In spray development, nozzle pressure is typically maintained at 1.0–2.0 kg/cm² and sump temperature variation is limited to ±2°C to avoid linewidth drift. Developer pH is commonly held between 10.4 and 10.8 for a fresh bath; as sodium carbonate absorbs carbon dioxide, pH drifts downward and breakpoint increases. Automatic replenishment using conductivity or pH control is required for continuous operation. In lines without automatic replenishment, the developer breakpoint shifts by 10–15 s per square meter of dry film processed, making fine-line geometry unstable. In dry film stripping after plating, sodium hydroxide concentration of 3–5 wt% at 45–60°C is used; strip time is 30–90 s for 25 µm film. Elevated strip temperature above 65°C can cause resist to re-adhere as a sludge, requiring filtration and spray nozzle cleaning.
| Process Step | Equipment Type | Reported Operating Range | Control Method |
|---|---|---|---|
| Lamination | Hot-roll laminator | 105–125°C, 0.3–0.5 MPa, 0.8–1.5 m/min | Contact pyrometer, nip pressure gauge |
| Exposure | 365–405 nm collimated flatbed or DMD direct imaging | 35–60 mJ/cm² | Calibrated radiometer |
| Development | Conveyorized spray developer | 0.8–1.2 wt% Na₂CO₃, 28–32°C, 45–90 s breakpoint | pH, conductivity, breakpoint titration |
| Stripping | Spray or immersion strip | 3–5 wt% NaOH, 45–60°C, 30–90 s | Visual inspection, residue count |
On production hot-roll laminators, lamination temperature, nip pressure, and speed are interdependent. For Apex 2000 at 25 µm thickness on 1.6 mm FR-4, typical settings are roll surface temperature 105–125°C, nip pressure 0.3–0.5 MPa, and linear speed 0.8–1.5 m/min. Thinner films tolerate higher speed; 50 µm films require lower speed to enable resist flow into copper grain boundaries. Copper pretreatment before lamination includes oxide removal, microetch to 0.8–1.5 µm mean roughness, and drying at 70–90°C. Surface roughness can be verified by contact profilometry according to ASME B46.1-2019. In humid environments above 60% RH, the film should be conditioned in a dry room for at least 4 h before lamination to prevent moisture entrapment at the film-copper interface. The dry film roll must not be exposed to ultraviolet light during handling, and yellow or amber safelight conditions below 500 lux are recommended. Lamination voids and entrapped air are observed when the primary roll temperature falls below 100°C on oxide-treated copper. Conversely, roll temperatures above 130°C cause premature thermal polymerization at the film edge and increased resist brittleness.
Batch-to-batch variance in roll tension is an observed production issue. If roll tension is not controlled within ±5% of the laminator setpoint, the film can shift laterally and create registration errors exceeding ±10 µm. Automatic optical alignment systems using fiducial targets are recommended when reverse-side imaging is used. The film’s polyethylene protective layer should be removed only immediately before lamination to prevent dust pickup and static discharge. Static charges above 2 kV on the panel surface can attract airborne debris and produce pinhole defects after development.
In acidic cupric chloride etching of 18–35 µm copper foil, a 25 µm resist thickness is generally sufficient when the etch factor is maintained between 2.5 and 3.0. The resist protects copper traces from lateral attack until the etch endpoint; over-etching beyond 120% of endpoint increases undercut and produces trace width loss. Alkaline ammoniacal etchants require a post-development heat stabilization of 100–110°C for 20–30 min to increase chemical resistance, but this reduces strip speed in alkaline strippers. In ferric chloride, resist lifting can occur at bath temperatures above 50°C when dwell time exceeds 120 s. For this reason, ferric chloride etching is usually limited to short-window processing or lower bath temperatures. The resist sidewall after etching is inspected for foot width and undercut using cross-sectional microscopy; acceptable undercut is typically less than 5 µm per side for 50 µm trace pitch.
For alkaline etching, the dry film resists attack at 45–55°C in pH-controlled baths. Spray impingement pressure is maintained at 1–2 kg/cm² to achieve uniform etch without resist lifting. Developer residue left on panel edges can cause localized resist breakdown in the etch chamber, so an adequate post-develop rinse with deionized water above 1 MΩ·cm resistivity is required. Fine-line etching with 25 µm lines on 12 µm copper foil may require a thinner resist of 15 µm to balance sidewall protection and strip speed. Published data for this specific configuration is limited, and first-article qualification on the actual etch line is necessary.
In pattern plating, Apex 2000 is imaged and developed to define circuit traces, then electroplating deposits copper, nickel, gold, or tin/lead into the resist channels. The film resists acidic copper sulfate and nickel sulfamate baths at temperatures up to 55°C and current densities of 2–4 A/dm². Bath temperatures above 60°C soften the resist and cause sidewall breakdown; high-speed acid copper baths are therefore operated at 45–55°C. For nickel/gold plating, the resist must withstand pH values below 2 in gold strike baths and nickel sulfamate at 45–55°C. The Electronic/EL grade designation is applied to lines where electroless copper follows dry film stripping, because residual developer salts and resist monomers can poison palladium-tin colloidal catalysts. The controlled ionic formulation reduces extractable residues, but users should verify surface cleanliness by IPC-TM-650 2.3.25 or equivalent before electroless catalyst immersion.
The principal difference between Apex 2000 and solvent-developable dry films is the removal of organic developer solvent from the imaging sequence. Solvent-developable films can provide good chemical resistance but require explosion-proof developing equipment, solvent recovery, and higher VOC control measures. Aqueous-processable films such as Apex 2000 have lower development-area emissions and simpler effluent treatment, but may require tighter control of developer pH and temperature. Compared with conventional aqueous dry films used for coarse-line work, Apex 2000 is reported to provide higher resolution and better adhesion at fine pitch. Compared with liquid photoresists, Apex 2000 offers pre-formed thickness uniformity and the ability to tent plated through holes without edge bead; however, it cannot be applied by electrostatic spray or roller coating, and the available thickness is restricted to the supplied roll thicknesses. Test methods used in comparative evaluation include IPC-TM-650 2.4.28.1 for adhesion, IPC-TM-650 2.3.25 for ionic cleanliness, and ASTM D3359-17 for cross-cut adhesion on copper. Resolution is assessed using line/space test patterns captured by optical microscopy, with tolerance ±2 µm.
| Property | Apex 2000 Electronic/EL | Conventional Aqueous Dry Film | Solvent-Developable Dry Film |
|---|---|---|---|
| Development medium | Aqueous Na₂CO₃ | Aqueous Na₂CO₃ | Organic solvent blend |
| VOC loading in develop | Low | Low | High |
| Minimum line/space | 25 µm | 50 µm typical | 25–30 µm |
| Thickness range | 15–50 µm | 25–75 µm | 15–40 µm |
| Electroless compatibility | Controlled ionic grade | Moderate | Limited |
| Drying/handling requirement | Dry room above 60% RH | Dry room above 60% RH | Solvent recovery required |
Apex 2000 should not be exposed to alkaline strippers containing amine-based additives before development, as these additives can permeate the resist and cause premature crosslinking or development inhibition. The product is incompatible with solvent-based solder mask developers and aggressive aromatic hydrocarbons. Storage before use is recommended at 5–20°C in a dry environment. Freeze-thaw cycles are not recommended; if a roll has been stored below 0°C, it should be allowed to equilibrate to room temperature for 12 h before opening the moisture barrier to prevent condensation on the film surface. Roll life after opening is limited by ambient humidity and ultraviolet exposure; opened rolls should be used within 7 days or sealed in a light-tight moisture barrier. The product is not intended for use with sub-15 µm thickness on 70 µm copper foil, because the resist cannot provide sufficient tenting strength over deep copper relief. It is also not recommended for use in nickel-phosphorus electroless baths above 85°C, where hydrolysis of the resist surface can elevate organic contamination. For compliance, the Electronic/EL grade should be evaluated under the applicable RoHS Directive 2011/65/EU and REACH Regulation EC 1907/2006 requirements, with lot-specific declarations obtained from the manufacturer.
