| HS Code | 449599 |
| Product Name | Asahi Kasei Apex 2000 Dry Film Photoresist |
| Type | Negative-tone aqueous-developable dry film photoresist |
| Film Thickness | Typically 25 to 50 µm |
| Resolution | Supports fine line and space patterns down to approximately 30 to 50 µm |
| Exposure Energy | Typical exposure energy range of 40 to 80 mJ/cm² |
| Developer | Aqueous developer such as 1% sodium carbonate solution |
| Stripping | Removable with aqueous alkaline stripping solution |
| Adhesion | Excellent adhesion to copper surfaces and laminate substrates |
| Copper Compatibility | Designed for use with copper foil, inner-layer circuits, and outer-layer plating |
| Sensitivity | High sensitivity for efficient and consistent photolithographic imaging |
| Shelf Life | Typically 6 months when stored in original sealed packaging |
| Storage Temperature | Store at 5 to 25°C in a cool, dark, dry place |
| Color | Blue dyed film for easy inspection and alignment |
| Processing | Suitable for roll-to-roll and panel plating processes |
As an accredited PCB Dry Film Photoresist Asahi Kasei Apex 2000 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Asahi Kasei Apex 2000 dry film photoresist is supplied as rolls, vacuum-sealed in light-proof, moisture-barrier bags with desiccant — one roll per bag. |
| Container Loading (20′ FCL) | 20′ FCL loading of PCB Dry Film Photoresist Asahi Kasei Apex 2000: secure rolls upright, protect from moisture and heat, no shifting. |
| Shipping | Ship PCB Dry Film Photoresist Asahi Kasei Apex 2000 as light-sensitive, moisture-protected rolls in sealed packaging. Avoid extreme temperatures and humidity. Handle as non-hazardous, but keep away from UV light and ensure proper labeling. Use reliable couriers with shock-resistant, opaque cartons to preserve film integrity during transit. |
| Storage | Store PCB Dry Film Photoresist Asahi Kasei Apex 2000 in a cool, dry, dark environment, ideally between 5–25°C (41–77°F). Keep rolls sealed in their original packaging to prevent moisture absorption and light exposure. Avoid direct sunlight, heat, and humidity. Under proper conditions, shelf life is typically six months; inspect before use. |
| Shelf Life | Shelf life is typically 6 months from manufacture when stored below 25°C in darkness, ensuring consistent performance. |
On multilayer PCB innerlayer production lines running 35 µm copper foil with 50 µm line/space rules, Asahi Kasei Apex 2000 is laminated as a 25 µm negative-acting aqueous-alkaline dry film resist. The copper surface is prepared by mechanical scrubbing with 400-grit pumice or chemical microetching to a surface roughness Ra of 0.25–0.35 µm before hot roll lamination at 105–115 °C, 0.4 MPa, and 1.0–1.5 m/min. The polyester cover sheet is removed after the board exits the laminator and cools below 35 °C, preventing residual acrylic monomer from re-adhering to the phototool. A collimated UV exposure unit with a 5 kW metal halide lamp delivers 60–80 mJ/cm² through a glass phototool; a Stouffer 41-step strip is used to confirm a clear step of 7–9 after development. Development in 1.0 wt% sodium carbonate at 30±1 °C for 45–60 s clears unexposed areas, while exposed line width is measured with a 200× optical microscope. The alkaline etch uses CuCl₂/HCl sprayed at 50–52 °C, with pH maintained at 1.2–1.8 and oxidation-reduction potential at 540–580 mV versus Ag/AgCl. Undercut below 5 µm is required after the breakpoint is reached; adhesion is checked on witness coupons using ASTM D3359-17 Method B with a 5B or 4B rating. After etch, the resist is stripped in 3–5 wt% NaOH at 45–50 °C, and microsections are evaluated per IPC-TM-650 2.1.1 for residual resist or copper overhang. Apex 2000 is not recommended for innerlayer processes where etchant temperature exceeds 55 °C because the resist softening increases the undercut rate non-linearly.
Outer layer pattern plating on rigid FR-4 panels uses the dry film as a plating mask rather than an etch mask. The film thickness selected is 38–40 µm, while the acid copper plating height is controlled at 20–25 µm; this provides a freeboard of at least 10 µm above the plated copper line. The copper bath is a high-throw CuSO₄/H₂SO₄ electrolyte operated at 20–25 ASF (2.0–2.5 A/dm²) with chloride ion at 50–70 mg/L and organic brightener maintained by cyclic voltammetric stripping. If the freeboard is reduced below 5 µm, copper grows laterally over the resist dam and produces mushroom-shaped profiles that short adjacent conductors. Resist adhesion to the plated copper and to the original copper-clad laminate is verified after plating by ASTM D3359-17 Method B tape pull; any lifting at the resist-to-plated-copper interface is classified as a major defect because it allows plating solution ingress and causes notch defects in the final conductor sidewall. Tin/lead plating follows at 15 ASF in a fluoroboric acid bath at 25 °C, after which the resist is stripped in 3–5 wt% NaOH at 45–50 °C for not less than 90 s. Stripping time below 60 s leaves acrylic residues in 75 µm spaces; these residues are detected by backlight inspection at 40× and scanning electron microscopy at 500×. The final surface insulation resistance is tested at 85 °C and 85% relative humidity under 100 V DC for 168 h per IPC-TM-650 2.6.14.1. A process conflict occurs when the acid copper bath brightener concentration exceeds the supplier upper limit: the deposited copper becomes brittle, while the resist swell in the acidic bath increases, leading to sidewall lifting that is not observed in laboratory coupon testing.
| Route | Lamination | Exposure | Development | Primary failure mode |
|---|---|---|---|---|
| Innerlayer 25 µm on 18 µm copper | 105–115 °C, 0.4 MPa, 1.0–1.5 m/min | 60–80 mJ/cm² | 1.0 wt% Na₂CO₃, 30 °C, 45–60 s | Etch undercut above 5 µm |
| Outer layer 38 µm pattern plating | 110–120 °C, 0.5 MPa, 0.6–1.0 m/min | 80–100 mJ/cm² | 1.0–1.2 wt% Na₂CO₃, 30–32 °C, 60–75 s | Plating bath lifting or notching |
| Via tenting 40 µm | 105–115 °C, 0.35 MPa, 0.5–0.8 m/min | 100–130 mJ/cm² | 1.1 wt% Na₂CO₃, 31 °C, 55–70 s | Tent puncture |
When via densities exceed 120 holes/dm², double-sided and multilayer boards are processed with dry film as a tent-and-cover etch resist. A 30–40 µm layer is laminated over drilled holes of 0.20–0.30 mm diameter; the hot roll conditions are 105–115 °C, 0.35 MPa, and 0.5–0.8 m/min. The film must bridge the hole after lamination without rupture, which is checked with backlight at 20×. Exposure at 100–130 mJ/cm² polymerizes the tent and the surrounding trace pattern; unexposed areas are developed in 1.1 wt% Na₂CO₃ at 31 °C for 55–70 s. During alkaline etching with NH₄OH-based or Na₂CO₃-compatible etchant at 45–50 °C, the tent must withstand spray pressure of 1.0–1.2 kg/cm² for 10–12 s. Tent puncture leads to etchant ingress into the via and subsequent barrel attack, which is detected in microsection per IPC-TM-650 2.1.1 as uneven copper wall thickness. Hole diameters above 0.40 mm are outside the practical tenting window for 40 µm dry film due to sag; such holes are plugged with resin or processed with liquid photoresist before etching. The thermal expansion mismatch between acrylic dry film and FR-4 substrate is approximately 40–60 ppm/°C versus 15 ppm/°C; board storage below 5 °C should be avoided before development to reduce tent cracking.
In lead frame chemical milling of copper alloys such as UNS C19400 and UNS C70250, the dry film is used as an etch mask over a cleaned metal surface. Lamination is conducted at 110–120 °C with a 25–50 µm film, depending on the required etch depth. Ferric chloride etchant is maintained at 42–48 Baumé, 45–50 °C, and sprayed at 1.0–1.5 kg/cm². Etch depth in copper alloy can reach 150–250 µm, so the resist breakthrough time must exceed the etch time by a safety factor of at least 1.5. On C70250 alloy, which contains 2.2–4.2 wt% nickel and 0.25–1.2 wt% silicon, adhesion is lower than on C19400; premature resist lifting occurs unless a benzotriazole-based pre-coat or pumice scrub with 400-grit is applied immediately before lamination. Pinhole density is evaluated by etching the resist-coated panel for twice the standard etch cycle and counting defects at 40×; acceptance is fewer than 0.1 pinholes/cm². The etch factor for 200 µm thick copper alloy parts is measured as 2.5:1–3.0:1 in production, with lower values on C70250 due to slower lateral dissolution and higher passivation tendency. After etching, the resist is stripped in 2–3 wt% KOH at 50 °C. The stripping solution and rinse water are monitored for copper and nickel under the facility discharge permit; the dry film itself is controlled under REACH Regulation (EC) No 1907/2006 Article 33 for SVHC communication and under Directive 2011/65/EU Annex II for RoHS-restricted substances, when the final component enters the EU market.
| Checkpoint | Standard or regulation | Acceptance condition |
|---|---|---|
| Dry film adhesion to copper | ASTM D3359-17 Method B | Rating 4B or 5B before etch |
| Microsection evaluation | IPC-TM-650 2.1.1 | No resist residue, no copper overhang |
| Surface insulation resistance after strip | IPC-TM-650 2.6.14.1 | Minimum 100 MΩ at 85 °C/85% RH |
| RoHS restricted substances | Directive 2011/65/EU Annex II | No Pb, Cd, Hg, Cr(VI), PBB, PBDE above thresholds |
| REACH SVHC communication | Regulation (EC) No 1907/2006 Article 33 | Article 33 declaration if SVHC above 0.1 wt% |
Copper pillar bumping at wafer level uses thick dry film as a plating mold on sputtered Ti/Cu seed layers. A 50–100 µm dry film is vacuum-laminated onto 200 mm or 300 mm wafers, with lamination temperature between 90–110 °C and chamber vacuum below 10 Torr. Exposure through a glass mask is performed on an i-line stepper or broad-band aligner at 365 nm, with dose increasing from 300 mJ/cm² for 50 µm film to 600 mJ/cm² for 100 µm film. Development uses 1.0–1.5 wt% sodium carbonate at 30–32 °C with ultrasonic agitation for 180–300 s, producing sidewall angles between 85° and 90°. The plating process fills the open areas with copper at 1.5–2.0 A/dm² to a height of 40–80 µm, followed by tin/silver cap plating. If the sidewall angle falls below 85°, seed-layer etching after stripping removes excessive copper at the pillar base and reduces the cross-sectional area of the interconnection. If the angle exceeds 90°, the resist overhang traps electrolyte and creates voids. Residue in the pillar base is checked by focused ion beam cross-section at 10,000× and EDX analysis. Published data for Asahi Kasei Apex 2000 in sub-50 µm copper pillar applications is limited; first article qualification with scanning electron microscopy and electrical continuity tests is required before production release.
In electroforming of nickel stencils and precision screens, the dry film is used as a mandrel mask over a passivated stainless steel substrate. The film thickness is selected between 25 µm and 75 µm to define aperture walls. Nickel sulfamate electrolyte is maintained at 55–60 °C, pH 3.8–4.2, and current density 2.0–5.0 A/dm². Internal stress of the nickel deposit is controlled in the range 0–50 MPa tensile by adjusting saccharin concentration from 0.5 g/L to 1.5 g/L. If the stress exceeds 50 MPa, the growing deposit curls the resist sidewall and creates an undercut path for nickel flash, shorting adjacent apertures. The resist foot must remain anchored to the mandrel throughout the plating cycle; mandrel passivation with chromium oxide or a release layer is adjusted so that the dry film adhesion is high enough to prevent lifting but low enough to permit clean stripping. After electroforming, the resist is removed in an alkaline stripper at 50 °C, and mandrel cleanliness is verified by EDX detection of carbon and oxygen; residual organic levels above 5 at% carbon indicate incomplete strip. Final apertures for solder paste stencils as narrow as 80 µm are measured by CNC vision with a tolerance of ±5 µm. Published data for Apex 2000 in continuous electroforming operations beyond 8 h bath immersion is limited; chemical compatibility testing with the specific nickel sulfamate formulation should be performed in advance.
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Asahi Kasei Apex 2000 is a negative-acting, aqueous-alkali-developable dry film photoresist supplied as a three-layer laminate consisting of a polyethylene terephthalate support film, the photopolymer resist layer, and a polyolefin cover sheet. The model designation Apex 2000 covers a series of dry film thicknesses used in printed circuit board outer layer pattern plating, inner layer etching, and through-hole tenting. Standard thickness values are 20 µm, 25 µm, 33 µm, and 40 µm, excluding carrier and cover layers. The resist is exposed with UV radiation in the 350–410 nm band and developed in dilute sodium carbonate solution. This differentiates it from solvent-processed dry films, which require organic solvent or solvent/alkali developer blends, and from liquid photoresists, which produce edge bead and less uniform coating on vertical surfaces. Because the resist is UV-sensitive, handling is performed under yellow safe lighting or low-UV white lighting. Users should confirm lot-specific total thickness, photo speed, and development latitude against the manufacturer’s certificate of analysis.
Unopened rolls stored at 18–22°C and 50–60% relative humidity typically remain processable for 6 months. Cold storage below 10°C requires equilibration to room temperature for 4–6 h before cover sheet removal to prevent condensation on the photopolymer surface. Lamination is carried out on hot-roll laminators with roll temperature 100–115°C, nip pressure 0.3–0.5 MPa, and speed 1.0–2.5 m/min. Lamination rolls with 60–70 Shore A silicone rubber durometer and total indicated runout below 0.05 mm reduce thickness variation and air entrapment. Vacuum lamination at 0.08 MPa is used for high-topography inner layers and thin cores. Copper surfaces are prepared by mechanical cleaning and microetching to 1.0–1.5 µm depth with sodium persulfate or sulfuric acid/hydrogen peroxide. Cleanroom conditions of class 10,000 are typical for dry film lamination of lines and spaces below 50 µm. Adhesion after development can be screened by cross-hatch tape pull adapted from ASTM D3359-17; a 5B classification indicates no removal. For dry film photoresists, tape type and dwell time must be specified because coating thickness is 20–40 µm. Published adhesion data for Apex 2000 at different microetch depths is limited; the stated range reflects general dry film practice on copper-clad laminate.
Development takes place in conveyorized spray chambers containing 0.8–1.0 wt% sodium carbonate at 28–32°C. Spray pressure is controlled at 1.5–2.5 bar, and the breakpoint is held between 40% and 60% of the chamber length. The sodium carbonate solution pH is typically 10.5–11.0; a fall below 10.5 slows development and leaves resist scum in fine spaces. Replenishment is controlled by conductivity or specific gravity rather than visual inspection alone. A 21-step Stouffer wedge is used to evaluate exposure response; a clear step of 7–9 after development is class-typical for aqueous dry film resists in this thickness range, but the exact value for Apex 2000 must be calibrated to the exposure unit and film thickness. Underdevelopment produces residue, reduced adhesion, and open circuits after etching. Overdevelopment narrows line widths and lowers tenting strength. In production, development breakpoint is recorded on control charts; a shift of 10% or more within a shift indicates sodium carbonate depletion, spray nozzle blockage, or temperature drift. The breakpoint is checked by stopping the conveyor with a half-developed panel and measuring the position of wet film removal. Since the resist is negative-acting, unexposed areas dissolve in the developer and exposed areas remain crosslinked.
Exposure uses UV sources in the 350–410 nm range, commonly 5 kW metal halide lamps in vacuum frames or LED direct imaging systems operating at 365 nm or 405 nm. Collimated UV improves sidewall angle and resolution on copper. The cover sheet is removed before lamination; the polyester carrier remains in place during exposure as an oxygen barrier and is peeled before development. Exposure energy at the resist surface is typically 20–45 mJ/cm² for aqueous dry films, with thicker films requiring higher energy. Apex 2000 photo speed should be confirmed using a radiometer matched to the lamp spectrum and the manufacturer’s exposure ladder. Vacuum frame pressure below 0.08 MPa is required for intimate phototool contact; air gaps at the phototool/resist interface degrade resolution and increase light scattering. Lamp aging shifts output, so radiometer checks are performed every 8 h shift or after lamp replacement.
Resolution of dry film photoresists is controlled by film thickness, exposure collimation, vacuum contact, and copper reflectivity. On smooth copper, 25 µm film typically resolves 25–50 µm lines and spaces with collimated UV; published data for Apex 2000 using standard resolution test patterns is limited, so production qualification should include a resolution target with the intended copper thickness. Laser direct imaging at 405 nm may be used, but depth of focus and photo speed must be re-characterized because laser spot size and dose distribution differ from vacuum-frame metal halide exposure. Sidewall angle after development should be checked by cross-section; vertical sidewalls reduce etch undercut and improve plating line shape. Thicker films of 33 µm and 40 µm provide greater tenting strength but reduce ultimate fine-line resolution because light scattering and development load increase with film thickness.
During acidic cupric chloride etching at 50°C, excessive spray impingement may produce undercut of 10–20% of resist thickness if conveyor speed and free chloride are not controlled. In ammoniacal alkaline etching, partially cured dry film may lose adhesion at high spray temperature; panels exposed to humidity after development should be held for minimum 24 h before etching only after adhesion confirmation. These limitations are common to aqueous dry film systems and should not be interpreted as Apex 2000-specific performance data. Etch factor should be monitored on first article panels to separate resist loss from process-level spray nozzle wear.
In pattern plating, Apex 2000 must withstand sulfuric acid/copper sulfate solution at pH below 1 and current densities of 1.5–2.5 A/dm² on vertical or horizontal plating lines. Outer layer copper plating thickness is commonly 25–35 µm; the use of 25 µm dry film for plating heights above 35 µm may produce bleed-out and resist lifting, particularly where solution impingement is high. Production-scale horizontal plating lines with high flow have shown resist lifting when developer breakpoint exceeds 60% or post-development rinsing is inadequate because residual carbonate at the resist/copper interface reduces adhesion. For plating above 25 µm, 33 µm or 40 µm film is specified to provide a wider process window. Plating compatibility is site-dependent and must be confirmed in a production cell because bath additives, chloride ion concentration, and air agitation influence resist adhesion under current load.
Through-hole tenting uses the dry film to bridge drilled holes and protect hole walls during etching. Tenting capability depends on film thickness, hole diameter, panel thickness, lamination temperature, and overdevelopment. For holes of 0.3–0.8 mm, 40 µm film is often selected. Vacuum lamination improves conformance around hole rims and reduces air entrapment. Hole rupture during etch or plating has been observed when lamination roll temperature falls below 100°C or when the resist is overdeveloped beyond 60% breakpoint. Published comparative data for Apex 2000 tenting strength against specific hole diameters is limited; qualification on production panels is required. Cross-sectioning of plated through-hole rims after lamination is used to detect resist thinning before etch.
Etching and stripping operations follow conventional aqueous dry film practice. In cupric chloride etching, spray pressure and free chloride are controlled to limit resist undercut; in ammoniacal etching, bath pH and copper concentration are managed within the etchant supplier’s range. After etching or plating, the resist is stripped in 2–3 wt% sodium hydroxide at 45–55°C, often with 1–2 wt% ethanolamine or ethylene glycol monobutyl ether as an accelerant. Stripped resist fragments are removed by in-line filtration to prevent re-deposition on copper traces. Post-strip rinsing with deionized water at 15–20°C is followed by hot-air drying. Waste developer and stripper streams require pH neutralization and copper precipitation before discharge. The aqueous process eliminates solvent recovery units but increases sodium loading in wastewater compared with solvent-based dry film processing.
The principal difference between Apex 2000 and solvent-processed dry films is the use of aqueous sodium carbonate development, which eliminates organic solvent in the developer but requires tighter control of temperature and concentration. The difference from liquid photoresists is the absence of edge bead and the availability of dry film thickness values of 20–40 µm for tenting; however, dry film cannot conform to blind microvias below 100 µm diameter. Published head-to-head data for Apex 2000 against other aqueous dry films is limited; lot-specific certification and in-line qualification should govern product selection.
| Processing attribute | Apex 2000 aqueous dry film | Solvent-processed dry film | Liquid photoresist |
|---|---|---|---|
| Developer | 0.8–1.0 wt% sodium carbonate at 28–32°C | organic solvent or solvent/alkali blend | dilute alkali or solvent depending on type |
| Thickness control | ±1–2 µm across panel | ±1–2 µm across panel | edge bead and dip-coating variation |
| Waste stream | aqueous sodium carbonate/caustic | solvent recovery or incineration | aqueous or solvent |
| Through-hole tenting | capable at 33–40 µm grade; qualification required | grade dependent | limited unless electrodeposited |
| Fine-line capability | 25–50 µm lines/spaces with 25 µm film class-typical | comparable | comparable but coating uniformity may limit |
Compliance with RoHS Directive 2011/65/EU and REACH Regulation EC 1907/2006 is confirmed through the supplier’s safety data sheet; the product is intended for industrial PCB manufacturing and not for direct food contact. FDA 21 CFR clearance is not implied. The aqueous development process does not use chlorinated solvents, but the photopolymer may contain acrylate monomers and photoinitiators. Operators should review the SDS for exposure limits and use nitrile gloves and safety glasses during handling.
Operational boundaries include lamination below 90°C, which may reduce adhesion, and development above 35°C, which may increase line narrowing. Storage above 25°C or exposure to UV light can cause thermal or photochemical fogging. Avoid contact with ketones, esters, and chlorinated solvents before development because these solvents may swell or dissolve the uncured resist. Alkaline cleaners should not be used immediately before lamination unless neutralized and dried. If relative humidity exceeds 65%, copper-clad laminate is pre-dried at 100–110°C for 30–60 min before lamination. Compared with liquid photoresists, Apex 2000 provides uniform dry thickness on vertical surfaces and hole rims but cannot fill deep blind microvias; compared with solvent-based dry films, the aqueous developer reduces volatile organic solvent loading but requires tighter control of sodium carbonate concentration and temperature because the development window is narrower.
