| HS Code | 608460 |
| Product Name | DuPont AZ-4620 |
| Photoresist Type | Positive |
| Exposure Wavelength | G-line (436 nm) |
| Viscosity | 500 cSt @ 25°C |
| Solids Content | 35% |
| Density | 1.03 g/cm³ |
| Film Thickness Range | 5–10 µm |
| Resolution | 2 µm |
| Sensitivity | 120 mJ/cm² |
| Developer Compatibility | AZ 400K series |
| Storage Temperature | 15–25°C |
| Shelf Life | 12 months |
As an accredited G-line Photoresist DuPont AZ-4620 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | DuPont AZ-4620 G-line photoresist is packaged in a sealed 4-liter amber bottle, protected from light and contamination. |
| Container Loading (20′ FCL) | 20′ FCL: packed in sealed drums/plastic containers, palletized, secured, labeled, temperature-controlled, no incompatible cargo, full container load. |
| Shipping | Ship G-line Photoresist DuPont AZ-4620 as a flammable liquid (Class 3) in approved, tightly sealed containers. Keep away from heat, sparks, and open flames. Use grounded equipment and ensure proper ventilation. Protect from direct sunlight and extreme temperatures. Follow local, national, and international transport regulations, including appropriate labeling and documentation for safe handling and delivery. |
| Storage | Store upright in tightly sealed, original container in a cool, dry, well-ventilated area away from heat, sparks, open flames, and direct sunlight. Recommended storage temperature is 15–25°C; avoid freezing and excessive heat. Prevent solvent evaporation and contamination. Keep away from oxidizers and foodstuffs. Follow manufacturer’s expiration guidance to maintain shelf life and performance. |
| Shelf Life | Shelf life is typically 12 months when stored unopened in original containers, protected from light at 5–25°C. |
During wafer-level packaging of copper pillar interconnects for peripheral and area-array flip-chip designs, undiluted AZ-4620 is coated on 200 mm and 300 mm wafers with a closed-bowl spin coater; typical post-softbake film thickness ranges from 6 µm to 10 µm at spin speeds between 2000 rpm and 3000 rpm. The formulation addition ratio for standard plating molds is 0 wt% reactive diluent, and no additional sensitizer or adhesion promoter is introduced; viscosity trimming is treated as a separate dilution process using propylene glycol monomethyl ether acetate in 5 wt% to 10 wt% increments only when a sub-6 µm target thickness is required and only after lot-to-lot spin-curve verification. Softbake is performed on a vacuum hotplate at 100 °C to 110 °C, followed by broad-band g-line and i-line exposure at 436 nm and 365 nm with an exposure dose between 200 mJ/cm² and 400 mJ/cm² depending on substrate reflectivity, proximity gap, and feature bias. Puddle or spray development in AZ 400K diluted 1:4 with deionized water clears the exposed vias; oxygen/argon plasma descum at low RF bias removes residual scum before copper electroplating in an acid copper sulfate bath. The plating template defines via openings for Cu pillar heights from 20 µm to 80 µm; resist sidewall angles and foot profiles are monitored by SEM cross-section because mushroom plating and void formation at the resist/seed interface are production-line failure modes. Terminal product types include copper pillar flip-chip bumps, wafer-level chip-scale package interconnects, and redistribution-layer capture pads. Applicable compliance controls include REACH Regulation (EC) No 1907/2006 Article 33 SVHC communication, CLP Regulation (EC) No 1272/2008 SDS classification, ISO 14644-1:2015 Class 5 wafer handling, and SEMI S2-0712 equipment safety for resist coat/develop tracks.
| Dimension | Standard / regulation | Verification point |
|---|---|---|
| Chemical registration | REACH (EC) No 1907/2006 | Article 33 SVHC communication |
| Classification and labelling | CLP (EC) No 1272/2008 | SDS delivery at point of use |
| Cleanroom environment | ISO 14644-1:2015 | Class 5 particle count during coating |
| Equipment safety | SEMI S2-0712 | Coater/developer track interlock and exhaust |
Silicon microstructures with etch depth exceeding 50 µm require a thick positive mask that survives alternating SF6 etch and C4F8 passivation cycles in an inductively coupled plasma deep reactive ion etching tool. Undiluted AZ-4620 is spin-coated to a post-softbake thickness of 8 µm to 12 µm and patterned without a top anti-reflective coat; the formulation addition ratio on MEMS production lines is 0 wt% additive, with no crosslinker, sensitizer, or dye doping introduced because dye loading alters sidewall absorption and critical dimension linearity. After softbake at 100 °C to 110 °C with time scaled to film thickness, and development in AZ 400K diluted 1:4, the resist mask enters a Bosch process where SF6 flows between 300 sccm and 700 sccm and C4F8 passivation cycles alternate at chamber pressures from 20 mTorr to 60 mTorr. Published selectivity data for this specific configuration is limited beyond vendor process notes; manufacturing lines therefore validate etch resistance with test-wafer depth measurements for each tool and lot. Production-line failure data show mask edge microcracking and foot undercut at etched depths approaching 80 µm if softbake time is shortened below 90 s or if the wafer is exposed to uncontrolled post-coat delay. Terminal products include inertial measurement unit proof masses, pressure-sensor diaphragms, microbolometer thermal isolation legs, and resonating structures for acoustic transduction. Compliance controls include ASTM E595-15 outgassing screening for MEMS sensors intended for vacuum or hermetic packages, ISO 14644-1:2015 Class 5 cleanroom handling, REACH Regulation (EC) No 1907/2006 Annex XVII restrictions, and SEMI S2-0712 for plasma etch tool exhaust interlock verification.
Electroformed nickel tools for microfluidic polymer replication are prepared by first defining a sacrificial photoresist master with AZ-4620 on a conductive seed layer. The standard formulation addition ratio is 0 wt% functional additive; when a lower dry-film thickness is required for fine channel geometries below 5 µm half-pitch, propylene glycol monomethyl ether acetate is introduced in small increments that are validated against spin-speed and softbake curves rather than fixed supplier recipes. The applied process uses spin coating on a 150 mm or 200 mm wafer, softbake at 100 °C to 110 °C, broad-band UV exposure through a dark-field mask, and development in AZ 400K diluted 1:4 to form concave channel walls and reservoir planes. After development, the master undergoes desiccated vacuum drying and nickel sulfamate electroforming at a current density between 1 A/dm² and 5 A/dm² until the deposited nickel reaches 1 mm to 2 mm thickness; internal stress is controlled by sulfamate bath temperature and agitation. The resist master is then stripped in solvent, and the nickel tool is used for injection molding or hot embossing of thermoplastic microfluidic chips. Terminal product types include point-of-care diagnostics cartridges, droplet generators, cell-culture perfusion chips, and capillary flow circuits. If a final device is marketed for medical diagnostics, end-product validation under ISO 10993-1:2020 may apply to the polymer materials; the photoresist itself is not present in the final device. Cleanroom compliance follows ISO 14644-1:2015 Class 5, and chemical handling records align with REACH Regulation (EC) No 1907/2006 and CLP Regulation (EC) No 1272/2008.
As flip-chip reflow moves to lead-free SnAgCu alloys, the electroplating mold for solder bumps must maintain consistent sidewall geometry to prevent plating bath entrapment and bump height variation. Undiluted AZ-4620 is coated on 300 mm wafers to a post-softbake thickness of 8 µm to 12 µm; the formulation addition ratio is 0 wt% reactive thinner, and no photosensitizer is added because the commercial novolak/diazonaphthoquinone balance is already adjusted for broad-band g-line and i-line response. The process sequence includes vacuum hotplate softbake at 100 °C to 110 °C, exposure at 365 nm with a dose from 200 mJ/cm² to 400 mJ/cm², puddle development in AZ 400K diluted 1:4, and oxygen descum before SnAgCu electroplating. The main thickness restriction is not coating capability but mechanical stability of the mold opening during fountain plating; at current densities above 2 A/dm² and bath temperatures above 40 °C, thin resist roofs over high-density solder openings can distort and produce mushroom bumps with nonuniform coplanarity. Production lines therefore cap bump height below 100 µm unless a double-coat or dry-film resist process replaces the single-coat AZ-4620 mold. Terminal product types include flip-chip ball grid array packages, wafer-level chip-scale packages, and automotive radar transceiver modules. Compliance interfaces include RoHS Directive 2011/65/EU Annex III for lead-bearing solder exemptions where applicable, JEDEC JESD22-A113 temperature cycling for final bump reliability, REACH Regulation (EC) No 1907/2006 Article 33, and ISO 14644-1:2015 Class 5.
Post-grind silicon interposers and via-middle TSV wafers receive a titanium-copper seed layer by physical vapor deposition before AZ-4620 is applied as a single-coat mold for redistribution-layer electroplating. The formulation addition ratio remains 0 wt% additive for standard 2 µm to 5 µm redistribution-layer line/space geometry; viscosity reduction by propylene glycol monomethyl ether acetate is employed only when linewidths under 2 µm require a thinner resist and is re-qualified for each seed roughness condition. The downstream process begins with spin-coating at 1500 rpm to 3000 rpm, softbake at 100 °C to 110 °C, broad-band g-line or i-line exposure on a mask aligner or stepper, and spray development in AZ 400K diluted 1:4. After oxygen/argon descum, electrolytic copper plating fills the vias and redistribution-layer traces using pulsed or periodic reverse pulse waveforms at 1 A/dm² to 3 A/dm²; copper thickness is typically 5 µm to 10 µm. The resist is then removed with solvent, and the exposed seed layer is etched using a wet copper etchant followed by a titanium etchant. Terminal product types include silicon interposer redistribution-layer layers, through-silicon via landing pads, and high-density fan-out redistribution layers for high-bandwidth memory stacks. Compliance controls include SEMI S2-0712 equipment safety, ISO 14644-1:2015 Class 5, REACH Regulation (EC) No 1907/2006, and JEDEC JESD22-A104 thermal cycling for final interposer qualification.
Display driver wafer maps for chip-on-glass and chip-on-film assembly require gold bumps of uniform height and tight top-surface coplanarity, which places the sacrificial mold thickness tolerance at ±1 µm across the wafer. AZ-4620 is coated undiluted to a target thickness of 8 µm to 10 µm and patterned with broad-band UV exposure; the formulation addition ratio is 0 wt% solvent for standard gold bump molds, and any propylene glycol monomethyl ether acetate dilution for thinner films is limited to 5 wt% increments with full bump height capability re-qualification. The process flow includes hotplate softbake at 100 °C to 110 °C, exposure at 365 nm, development in AZ 400K diluted 1:4, and oxygen plasma descum before gold electroplating in a cyanide-free sulfite gold bath or cyanide-based gold bath at 0.5 A/dm² to 2 A/dm². The mold must tolerate bath pH above 8 and temperature above 50 °C without pattern lifting; this is the main production-line failure mode when edge bead removal and dehydration bake are omitted. Terminal product types include gold bump display driver ICs for chip-on-glass modules, chip-on-film packages, and optoelectronic device arrays. Compliance controls include REACH Regulation (EC) No 1907/2006, CLP Regulation (EC) No 1272/2008, ISO 14644-1:2015 Class 5, and RoHS Directive 2011/65/EU for final electronic assemblies. Published data for specific gold bath compatibility with AZ-4620 is limited; compatibility is validated on a per-bath chemistry basis using adhered nickel/gold coupons.
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DuPont AZ-4620 is a positive-tone, g-line-sensitive photoresist formulated on a novolak–diazonaphthoquinone matrix. The product is supplied as a filtered, solvent-borne liquid with a typical kinematic viscosity near 400 mm²/s at 25 °C and is specified for single-coat film thicknesses from approximately 6 µm to 20 µm. Primary uses include gold bump plating, copper pillar plating, solder bump formation, MEMS sacrificial and etch masks, and wafer-level plating molds. The DNQ-novolak system is positive-tone: exposed areas undergo Wolff rearrangement to indene carboxylic acid and dissolve in aqueous alkaline developer, while unexposed areas remain resistant enough to serve as an electroplating mask. Supplier documentation identifies g-line exposure at 436 nm, with processing possible on broadband mercury arc aligners in the 405–436 nm range. The material is typically filtered to 0.2 µm or finer for defect control. Compared with thin-film AZ 1500-series resists, AZ-4620 increases single-coat thickness by roughly 5× to 10× while retaining positive-tone develop/removal behavior. Compared with SU-8 negative epoxy resists, AZ-4620 avoids cationic crosslinking and can be stripped by organic solvents after electroplating; however, its resolution is lower and its practical thermal stability is limited when hardbake exceeds 130 °C.
Because the DNQ photoactive compound bleaches at g-line wavelengths, exposure can penetrate through thick films more uniformly than non-bleaching resists; however, residual solvent from insufficient softbake raises the dose-to-clear and increases film-thickness-dependent exposure variation. The unexposed novolak matrix is dissolved slowly by standard alkaline developers, so development endpoint control limits sidewall undercut. For electroplating applications, the resist sidewall profile after development is a critical mold attribute; a straight or slightly re-entrant profile may be produced by adjusting softbake, exposure focus, and developer concentration on a contact aligner. Production-scale equipment used for AZ-4620 processing includes automatic coat/develop tracks such as the TEL ACT 8 and Süss MicroTec ACS200, manual or semi-automated mask aligners such as the SUSS MA6/BA6 or EVG 620, and contact profilometers or spectroscopic reflectometers for film-thickness verification.
Representative spin-curve values for a closed-bowl coater with static dispense, 3000 rpm/s acceleration, and 30 s spin time are approximately 12 µm at 1000 rpm, 8.5 µm at 2000 rpm, 7 µm at 3000 rpm, and 6 µm at 4000 rpm. Film thickness is also influenced by bowl exhaust, lid temperature, and wafer backside cooling; a change in exhaust balance alters solvent drying rate and can shift the spin curve by several tenths of a micrometer. Thickness uniformity on 200 mm wafers is typically controlled to less than ±2% using a hotplate-bake track, but batch-to-batch viscosity variation requires verification against the supplier certificate of analysis and a pre-production coat test. Softbake is commonly performed on a hotplate at 100 °C for 1 min/µm of film thickness; hotplate vacuum contact or proximity gaps must be minimized to avoid skin formation and entrapped solvent. Oven bakes are less repeatable for films above 10 µm because the surface dry layer can slow solvent removal from the bulk film.
Exposure dose for a 10 µm film on a mercury arc contact aligner is typically in the range of 200–300 mJ/cm² when the lamp is calibrated at 405 nm and 436 nm. Insufficient dose leaves residual DNQ at the substrate interface and produces footed profiles; excessive dose reduces linewidth and can cause sawtooth sidewalls. Development with AZ 400K diluted 1:3 in deionized water, or with metal-ion-free AZ 726 MIF, is carried out at 21–23 °C with immersion or puddle agitation for 2–5 min depending on film thickness. Spray development on an automatic track increases contrast but may increase surface roughness if the spray pressure is excessive. Cleanroom processing is normally performed under ISO 14644-1:2015 Class 5 or Class 6 conditions to reduce airborne particle defects during coat, bake, align, and develop.
After development, a hardbake at 100–120 °C for 2–5 min on a hotplate is often inserted to improve adhesion and reduce developer absorption before electroplating. Hardbake above 130 °C can partially crosslink the novolak matrix, increasing strip time and raising the risk of organic residue after downstream plasma descum. The resist mold is compatible with acidic electroplating chemistries including copper sulfate, nickel sulfamate, and tin-silver formulations. A copper sulfate bath at 0.8–1.2 A/dm² and 25–30 °C, or a nickel sulfamate bath at 50–55 °C and pH 3.8–4.2, can be used when the AZ-4620 thickness is selected to give at least 1.2× the target plated-metal height. Plated metal stress above the tensile limit of the novolak film can cause sidewall cracking, particularly at thickness ratios approaching 1:1; published data for specific device configurations is limited, so plating trials on representative topography are necessary before lot release.
Resist removal after electroplating is typically performed with NMP, AZ 100 Remover, or equivalent solvent strippers at 60–80 °C. Ultrasonic agitation shortens removal time but may damage high-aspect-ratio plated structures. Oxygen plasma ashing at 100–150 °C removes organic residue but can oxidize copper or silver surfaces, requiring a subsequent oxide removal step. Compared with SU-8, AZ-4620 does not require aggressive plasma ashing or molten salt stripping; this is a process advantage when plated features are sensitive to oxidation or thermal budget. However, the novolak matrix is not suited to prolonged exposure to strongly alkaline plating baths above pH 10, because alkaline attack increases dark erosion and roughens the mold sidewall.
AZ 1500-series thin resists produce films in the 1–3 µm range and generally do not require dedicated edge-bead removal or thick-film softbake profiling. AZ-4620 at 12 µm can exhibit an edge bead that is 2–3× the interior film thickness, which degrades mask contact and critical-dimension uniformity in contact lithography. A solvent edge-bead removal line using PGMEA or an equivalent approved solvent is therefore applied during spin or immediately after coating. The exact EBR nozzle position is set by the wafer diameter and the exclusion zone, typically 3–5 mm from the edge for 200 mm substrates. On wafers with pre-existing topography, AZ-4620 planarizes depressions better than 1–2 µm resists but does not offer the complete planarization of dry-film resists. Multiple spin coats increase film thickness but introduce interfacial strain and require dehydration bakes between coats; spray coating is an alternative for severe cavity or bump topography, though solvent retention in spray-coated films must be controlled by extended softbake or vacuum contact bake.
Compared with AZ 9260, which is used for single-coat films from 20 µm to 100 µm, AZ-4620 has lower viscosity and is easier to degas, but it cannot reach very thick single-coat targets without multiple coats. Adjacent AZ 4000-series thick resists may offer slightly different viscosity, so selection should be made from the current supplier spin curve rather than from nominal viscosity alone. Replacing a thin resist with AZ-4620 changes exposure time, depth-of-focus effects in projection lithography, development time, and strip time; these changes are manageable on contact/proximity aligners but require process requalification on steppers because the thick film may exceed the available depth of focus.
Storage of AZ-4620 at 4–8 °C extends shelf life; bottles must be equilibrated to 20–25 °C for at least 24 h before opening to avoid moisture condensation. Batch-to-batch lot release documentation under ISO 9001:2015 includes solids content, kinematic viscosity, and trace metals; viscosity may be reported according to ASTM D445-21 or an equivalent internal polymer-solution method. Safety data sheet review under EU Regulation 1907/2006 (REACH) is required before installation because the solvent system contains PGMEA, which has a flash point and requires local exhaust ventilation. Final device RoHS compliance is determined by the full material set after stripping and cleaning, not by the resist alone.
Common production failure modes include edge-bead lifting during softbake, bubbles from insufficient softbake, plating-bath attack at developer residues, resist cracking under high plated-metal stress, and incomplete stripping after hardbake above 130 °C. These are managed by controlling hotplate ramp rates, dispense volume, EBR solvent flow, developer replacement intervals, and hardbake temperature. A lot monitoring plan that records spin speed, exhaust setting, hotplate temperature, exposure dose, developer concentration, and strip time provides the numerical baseline needed to maintain a stable thick-resist process across production shifts.
