| HS Code | 595591 |
| Purity | High purity formulation with minimal metallic and ionic impurities. |
| Outgassing | Very low outgassing under vacuum and thermal cycling. |
| Adhesion | Excellent adhesion to silicon, ceramic, glass, and metal substrates. |
| Temperature Resistance | Stable performance from -65°C to +200°C or higher. |
| Ionic Contamination | Extremely low levels of chloride, sodium, and potassium ions. |
| Dielectric Strength | High electrical insulation with dielectric strength above 15 kV/mm. |
| Thermal Conductivity | Enhanced thermal conductivity for effective heat dissipation. |
| Moisture Resistance | Low moisture absorption with strong resistance to humid environments. |
| Chemical Resistance | Resistant to common solvents, fluxes, and process chemicals. |
| Mechanical Integrity | High mechanical strength and impact resistance after curing. |
| Curing Profile | Cures rapidly at moderate temperatures with low shrinkage. |
| Shelf Life | Extended shelf life under recommended storage conditions. |
As an accredited Electronic Grade Packaging Adhesive Electronic/EL Grade factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Available in 1 kg sealed containers, this Electronic Grade Packaging Adhesive (Electronic/EL Grade) ensures high purity and reliable performance. |
| Container Loading (20′ FCL) | A 20′ FCL shipment of Electronic/EL Grade Packaging Adhesive, packed in sealed drums/pails, secured upright, protected from moisture and contamination. |
| Shipping | Ship as a moisture-sensitive, electronic-grade material in sealed, clean containers to prevent contamination. Maintain controlled temperature away from heat and direct sunlight. Ensure proper labeling, packaging, and documentation per hazardous goods regulations if applicable. Use dedicated transport to avoid cross-contamination, with careful handling to preserve purity and performance. |
| Storage | Store in original, tightly sealed containers in a cool, dry, well-ventilated area away from direct sunlight, heat, and ignition sources. Keep protected from moisture and contamination. Recommended storage temperature: 5–35°C (41–95°F). Avoid prolonged exposure to air and humidity. Ensure shelves are stable and containers are clearly labelled. |
| Shelf Life | Shelf life is typically 12 months from manufacture date when stored sealed, dry, and at controlled room temperature. |
Electronic/EL-grade packaging adhesive is specified by extractable ionic cleanliness, outgassing under vacuum bake, and the absence of chloride species that compromise aluminum bond-pad corrosion resistance. The downstream applications below are limited to established electronic-packaging routes in which the material functions as a resin matrix, die-attach vehicle, capillary underfill base, lid-seal compound, or glob-top precursor. Formulation ratios are wet-formulation mass percentages, not dry-film fractions.
In high-volume QFN and DFN assembly, the EL-grade adhesive is used as the resin matrix in silver-filled die-attach pastes at 12–17 wt% of the total wet formulation, with silver flake at 78–85 wt%, anhydride hardener at 1.5–3.0 wt%, and silane coupling agent at 0.2–0.8 wt%. Dispensing occurs through time-pressure or auger valves onto electroplated silver or bare copper leadframes, followed by die placement at 2–5 N contact force and snap cure in an inline conveyor oven at 175 °C for 60–120 s; alternatively, staged cure at 120 °C for 20 min followed by 175 °C for 30 min is applied when lower void rates are required. Compliance on the assembly line is referenced to MIL-STD-883J Method 5011.11 for die shear, IPC/JEDEC J-STD-020F for moisture sensitivity classification before reflow, ASTM D3418-21 for glass transition temperature by differential scanning calorimetry, and IPC-TM-650 2.3.28 for chloride and bromide extraction by ion chromatography. Ion chromatography is included because chloride above 20 ppm in the cured paste can reduce wire-bond adhesion on aluminum bond pads after biased humidity storage, while low-molecular-weight ionic species increase leakage current in packages rated for 500 V operation. Terminal products include QFN packages with 0.4 mm lead pitch, power DFN packages, smart power modules, and automotive sensor leadframe packages that retain die shear after 1,000 h at 150 °C. The formulation boundary is pot life: once mixed with a high-activity anhydride curative, the material drops below printable viscosity after 8 h at 25 °C, so frozen one-component versions are specified for lines with extended idle periods.
Mid-power LED leadframe assembly imposes a narrower processing window because volatiles from die-attach material deposit on phosphor coatings and reduce luminous flux maintenance. In white LED packages, the EL-grade adhesive is formulated as a low-outgassing die-attach layer at an adhesive resin content of 15–20 wt%, with submicron fused silica at 20–30 wt%, silver-coated copper or silver flake at 50–65 wt%, and cure accelerator at 0.3–0.7 wt%. The material is dispensed into PPA or PCT leadframe cavities, the LED chip is placed, and the adhesive is cured at 100 °C for 2 h followed by 160 °C for 3 h in a nitrogen-purged oven because oxygen at the elevated temperature accelerates yellowing of the aromatic resin fraction. Compliance for the segment is referenced to ASTM E595-22 total mass loss below 0.5% and collected volatile condensable material below 0.1%, IEC 62717:2018 for LED module performance, and IPC/JEDEC J-STD-020F moisture sensitivity level 3 or better. A production-line failure signature specific to this segment is die tilt after cure: if filler and resin fractions separate during dispensing, chip edges lose adhesion and the package fails high-temperature operating life at 85 °C/85% RH. End-product types include 2835, 3030, and 5050 surface-mount LED packages, automotive exterior lighting arrays, and horticultural modules with extended 12 h daily high-current operation. The material is not compounded with sulfur-bearing accelerators because sulfur migration into silver-plated leadframes creates silver sulfide migration paths that appear as current leakage between package terminals after 1,000 h of biased damp heat.
A capillary underfill is introduced into the 20–45 µm standoff gap between a flip-chip die and an organic substrate after reflow soldering, with substrate preheat held at 80–110 °C to lower viscosity while avoiding premature cure. For this segment, the EL-grade adhesive forms the resin fraction of a silica-filled underfill at 28–38 wt%, with fused silica at 60–70 wt%, latent imidazole catalyst at 0.5–1.0 wt%, and coupling agent at 0.3–0.5 wt%. The dispensed fillet is pulled by capillary action under the die; process engineers specify a fillet height of 25–50% of the die thickness and reject parts where non-wetting extends beyond 1.5 mm along any die edge. Cure is performed in a convection oven at 150 °C for 30 min, after which the underfill is inspected by C-mode scanning acoustic microscopy for voids larger than 100 µm. The governing compliance set is IPC-9691C for flip-chip assembly requirements, ASTM D2556-14 for viscosity and thixotropy, ASTM D3418-21 for the glass transition temperature of the cured network, and IPC/JEDEC J-STD-020F for moisture sensitivity classification of the assembled component. The critical processing risk is void entrainment at the die inlet: if the underfill is dispensed above 110 °C, pot life falls below 2 h, and if dispensed below 80 °C, viscosity exceeds 20,000 mPa·s, preventing complete gap fill. Terminal product types include mobile application processors in flip-chip ball grid array packages, GPU substrates with 55 mm × 55 mm die dimensions, and RF front-end modules where underfill coverage must extend beneath 0.6 mm-square transmit/receive switches without fillet spreading onto adjacent antenna keep-out areas.
For ceramic leadless and metal-lid packages, the EL-grade adhesive is compounded as a one-component, thixotropic lid-seal material with a resin content of 30–42 wt%, spherical silica filler at 55–68 wt%, silane adhesion promoter at 0.5–1.0 wt%, and non-conductive carbon black marker at 0.1–0.3 wt% where laser marking contrast is required. The paste is dispensed through a 0.25–0.45 mm needle onto the package shelf, the lid is placed with 1–2 N closure force, and the assembly is cured at 150 °C for 1 h. Compliance is evaluated against MIL-STD-883L Method 1014.12 for gross and fine leak after thermal cycling from −65 °C to 150 °C for 500 cycles, ASTM E595-22 for outgassing in vacuum-baked packages, and MIL-PRF-38534 for hybrid microcircuit package acceptance. The processing boundary is fillet geometry: if the material flows into the cavity by more than 0.3 mm after lid placement, MEMS membranes or wire bonds become contaminated during cure; if the fillet is narrower than 0.15 mm, gross leak failures appear within the first 50 thermal cycles. Terminal parts include MEMS inertial measurement units, barometric pressure sensors, oven-controlled crystal oscillators, and hermetic image-sensor packages where cavity pressure must remain below 10 mbar after sealing.
Glob-top encapsulation on chip-on-board substrates uses the EL-grade adhesive as the base resin in a heavily filled system: the formulation contains 70–80 wt% spherical silica filler, 15–25 wt% high-purity resin, 0.3–0.8 wt% carbon black for light blocking, and 1–2 wt% flexibilizer to control modulus and warp on thin FR-4 or polyimide carriers. The material is applied as a dam around the die perimeter, followed by a fill dispense that must avoid air entrapment at the wire-loop apex; vacuum degassing is conducted at 100–150 Pa for 5–10 min before thermal cure at 120 °C for 4 min followed by 150 °C for 1 h. Compliance is referenced to UL 94 V-0 at a thickness of 1.5 mm, ASTM D2240-15 for Shore D hardness, ASTM D149-20 for dielectric strength, and MIL-STD-883J Method 2011.8 for wire bond pull after encapsulation. The main operational boundary is moisture uptake: if the uncured material is held in the dispense reservoir at 25 °C and 60% RH for more than 4 h, absorbed moisture produces voids during cure above 120 °C, resulting in dome cracks after 100 thermal cycles. Terminal products include smart-card microcontroller modules with 0.18 mm loop heights, optical proximity sensor chip-on-board assemblies, LED array modules for automotive interior illumination, and printed circuit board assemblies requiring dust and mechanical protection without hermetic packaging.
For insulated-gate bipolar transistor modules and power discrete packages that require die attach with controlled electrical conductivity, the EL-grade adhesive is compounded into a silver-filled electrically conductive paste at 10–15 wt% resin fraction, 80–85 wt% silver flake, 2–4 wt% conductive carbon or low-oxide silver-coated copper filler, and 0.5–1.0 wt% wetting agent. The paste is printed or dispensed onto nickel-plated or silver-plated copper substrates, the die is placed with 3–6 N pressure, and the assembly is cured at 175 °C for 60 min in an inert atmosphere to prevent oxidation of the silver network. Electrical and thermal parameters are verified using ASTM D257-14 volume resistivity, with accepted production values in the range of 5 × 10−4 Ω·cm to 8 × 10−4 Ω·cm, and ASTM D5470-17 for thermal conductivity, with accepted die-attach values of 20–40 W/(m·K) for silver-filler systems. Packaging compliance is referenced to MIL-STD-883J Method 5011.11 for die shear at 25 °C and after 260 °C reflow conditioning; the formulation also avoids total bromine and chlorine above 900 ppm to meet REACH Regulation (EC) No 1907/2006 and Directive 2011/65/EU RoHS restrictions. The critical limitation is the absence of true metallic sintering: this conductive adhesive is not a substitute for silver sintering paste at operating junction temperatures above 175 °C, because the polymer network retains only limited shear strength above 200 °C and may show property cliff-edge degradation after continuous exposure at 200 °C for 500 h. Terminal products include IGBT modules for motor drives, silicon-carbide power discretes in high-voltage converter stages, and RF power amplifiers where solder reflow would exceed the temperature tolerance of adjacent gallium-nitride passivation layers.
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Electronic Grade Packaging Adhesive Electronic/EL Grade is supplied under model designation EL-4601 as a two-component, solvent-free anhydride-cured epoxy system. The recommended mix ratio is 100:22 by weight resin to hardener. The material is formulated for semiconductor package assembly: capillary underfill for flip-chip and chip-scale packages, glob-top encapsulation of wire-bonded die, and lid-seal attachment for ball grid array and land grid array packages. In the cured state, the product provides a volume resistivity of 9.0 × 10^15 Ω·cm after 85 °C / 85% RH exposure for 168 h when tested per ASTM D257-14. Its primary differentiation from general-purpose electronic adhesives is the combination of a ≤ 5 ppm extractable chloride limit, low outgassing, and a sub-45 ppm/°C coefficient of thermal expansion below the glass transition temperature. The uncured material is filled with fused silica to yield a thixotropic flow profile suitable for needle dispensing or jetting, but the filler package is non-conductive and non-magnetic, which permits use adjacent to Cu pillar and Au wire bond interconnects. The product is available in 30 mL syringes, 100 g cartridges, and 1 kg jars with desiccant-packed aluminium-foil pouches. Storage of frozen single-component formats is required at -40 °C; the two-component bulk format is stored at 5 °C and must be warmed to 25 °C before mixing to avoid moisture condensation.
For package reliability, the controlling specification is not lap shear strength alone but the mobile ion and condensable volatile content after cure. The EL Grade is tested by ion chromatography after 80 °C water extraction for 60 min in accordance with IPC-TM-650 method 2.3.28. The production release limit for extractable chloride is ≤ 5 ppm; sodium and potassium are each limited to ≤ 2 ppm; ammonium is limited to ≤ 10 ppm. These thresholds are below the typical 50–300 ppm chloride range seen in industrial-grade epoxy adhesives because the anhydride hardener and epoxy resin are selected from high-purity, low-hydrolyzable-chloride starting materials. Outgassing is measured by ASTM E595-15; the material demonstrates total mass loss of ≤ 0.10 % and collected volatile condensable material of ≤ 0.01 %. High-purity silica filler is passivated with an organosilane coupling agent, and the formulation contains no intentionally added silicone, amine, or transition-metal catalyst.
| Property | Test method | Value |
|---|---|---|
| Mixed viscosity at 25 °C, 5 rpm | ASTM D2196-20 | 5,500 mPa·s |
| Thixotropic index, 0.5/5 rpm | ASTM D2196-20 | 3.2 |
| Pot life at 25 °C, 100 g mass | ASTM D2471-15 | 6 h |
| Cure schedule | Supplier specification | 150 °C for 30 min or 165 °C for 10 min |
| Glass transition temperature by DMA | ASTM E1640-18 | 140 °C |
| Coefficient of thermal expansion below Tg | ASTM E831-19 | 42 ppm/°C |
| Coefficient of thermal expansion above Tg | ASTM E831-19 | 118 ppm/°C |
| Lap shear on aluminium at 25 °C | ASTM D1002-10 | 12.5 MPa |
| Volume resistivity after 85 °C / 85% RH, 168 h | ASTM D257-14 | 9.0 × 10^15 Ω·cm |
| Water absorption, 24 h immersion | ASTM D570-98(2021) | 0.25 % |
| Extractable chloride | IPC-TM-650 2.3.28 | ≤ 5 ppm |
| Outgassing total mass loss | ASTM E595-15 | ≤ 0.10 % |
In high-volume flip-chip lines using positive-displacement auger valve dispensers with 30 mL syringes, the relevant failure modes are not bond-line cohesive fracture but filler settling during idle periods and moisture uptake during open staging. Production lots are therefore characterized for viscosity recovery after 72 h ambient idle; the target is a shift of ≤ 10 % from initial mixed viscosity. Published data for this specific configuration is limited; production approval requires lot-level flow-time runs against a reference die. The material is also supplied in jetting-compatible packages, but jet-valve shear can exceed 100,000 s^-1 at the nozzle. Lot qualification includes viscosity before and after 10,000 cycles of jetting to confirm filler suspension stability.
For a flip-chip with a standoff gap of 25–80 µm, the mixed adhesive is usually dispensed at a substrate temperature of 80–100 °C to lower viscosity and accelerate capillary flow. Needle inner diameter is selected between 0.20 mm and 0.33 mm, with dispense shot volume from 0.20 mg to 1.5 mg depending on die edge length and fillet design. The flow time to complete underfill for a 10 mm × 10 mm die at 80 °C is typically 60–180 s; production lines should verify lot-to-lot flow time against a reference die because filler particle-size distribution shifts of 5 % can extend capillary penetration. The substrate should remain at dispense temperature for 15–30 min after flow completes to allow fillet bleed-out and reduce trapped air, then oven cure at 150 °C for 30 min or inline cure at 165 °C for 10 min. Void content in the final fillet is inspected by scanning acoustic microscopy; acceptance thresholds are typically ≤ 1 % total fillet void area. At relative humidity above 60 %, die and substrate should be prebaked at 125 °C for 2 h because moisture absorbed by organic solderability preservatives and die passivation can vaporize during underfill flow and create interfacial voids. The material is incompatible with amine-based flux residues at the die edge; these residues catalyze the anhydride-epoxy reaction prematurely and produce hard gel particles ahead of the flow front. Continuous use with tin-catalyzed condensation-cure silicones in the same cavity is not recommended without a narrow thermal or physical separation step because low-molecular-weight tin species can migrate and alter cure kinetics.
For lid-seal attachment, the EL Grade is dispensed as a continuous bead on a metal or ceramic lid; typical bead width is 0.30–0.60 mm with a wet height of 0.20–0.40 mm. The package is closed under a clamp load of 0.5–2.0 N per linear cm and cured at 150 °C for 30 min. The cured adhesive provides a moisture barrier rather than a hermetic seal; water vapor transmission rate is controlled by the fused silica filler and high crosslink density. For glob-top encapsulation of wire-bonded die, the high thixotropic index of 3.2 maintains a dam profile and prevents bleed onto wire bond pads. Needle dispense is preferred over jetting for large glob volumes; flow-out is observed at 85–100 °C to release trapped air before gelation. The upper use temperature for continuous exposure is 150 °C; short-term excursions to 260 °C during solder reflow are tolerated by the cured network for ≤ 90 s. The material is not recommended for applications requiring rework by solvent immersion because the high crosslink density resists common electronic solvents. Mechanical removal and repolish are required after gross misalignment or incorrect lid placement.
Unlike industrial-grade epoxy adhesives, the EL Grade is not a repackaged structural bonding compound. The specifying difference is the ionic cleanliness and outgassing envelope, not the cured hardness or lap shear. Industrial adhesives commonly contain 50–300 ppm extractable chloride from epichlorohydrin-derived resins; the EL Grade imposes a ≤ 5 ppm release limit and validates each lot by ion chromatography. Silver-filled conductive adhesives have volume resistivity in the range of 1 × 10^-4–1 × 10^-3 Ω·cm and are used for die attach where electrical conduction is required, but they introduce bleed-out and shorting risk in underfill or lid-seal applications. The EL Grade remains electrically insulating at 9.0 × 10^15 Ω·cm after damp heat conditioning. UV-curable packaging adhesives cure in 10–30 s under 365 nm irradiation but leave shadow regions uncured beneath opaque die; the EL Grade is thermally cured and therefore develops a uniform network in shadowed areas. Silicone packaging gels offer 0.1–1 MPa modulus and high elongation, but they lack the 42 ppm/°C CTE and the 2.4 GPa storage modulus required to stiffen large flip-chip die against solder bump fatigue.
| Parameter | EL Grade | Industrial Epoxy | Silver-Filled Conductive | Silicone Encapsulant |
|---|---|---|---|---|
| Volume resistivity | 9.0 × 10^15 Ω·cm | 10^12–10^14 Ω·cm | 1 × 10^-4–1 × 10^-3 Ω·cm | 10^14–10^15 Ω·cm |
| Extractable chloride | ≤ 5 ppm | 50–300 ppm | 20–100 ppm | 10–50 ppm |
| CTE below Tg | 42 ppm/°C | 65–100 ppm/°C | 75–120 ppm/°C | 250–350 ppm/°C |
| Storage modulus at 25 °C | 2.4 GPa | 2.0–3.5 GPa | 1.5–3.0 GPa | 0.001–0.01 GPa |
| Outgassing total mass loss | ≤ 0.10 % | 0.5–1.5 % | 0.2–0.8 % | 0.1–0.5 % |
| Primary use case | Underfill, glob top, lid seal | General bonding | Die attach, EMI shielding | Stress relief, encapsulation |
Qualification data for package-level thermal cycling from -55 °C to 125 °C show that the EL Grade shifts failure modes from bulk cohesive cracking of the underfill to solder bump fatigue at the die edge. The low CTE below Tg of 42 ppm/°C reduces the global coefficient of thermal expansion mismatch between silicon die and organic substrate. The material is qualified against JEDEC J-STD-020 moisture sensitivity level 3 for reflow at 260 °C peak temperature; packages that have absorbed moisture above 0.25 wt% should be baked at 125 °C for 12 h before reflow. In open-air reflow, the cured adhesive does not exhibit measurable weight loss below 300 °C by thermogravimetric analysis at 10 °C/min under nitrogen, which supports the low-outgassing requirement in cavity packages. Because the material is a rigid epoxy network, it is not a drop-in replacement for low-modulus silicone encapsulants in packages with large die-to-lid spacing and high thermal expansion mismatch. The operational boundary for continuous use is 150 °C; exposure above 175 °C for more than 1,000 h may produce progressive oxidative darkening and a measurable increase in storage modulus but is not accompanied by rapid ionic release.
Production-scale use is differentiated by the lot-release certificate rather than by visual appearance alone. Each lot of EL Grade is checked for mixed viscosity, extractable chloride, outgassing, and lap shear before shipment. On manufacturing lines with twin-screw or planetary mixing, the two components must be homogenized under vacuum to avoid air entrapment, but the product is supplied pre-degassed to a wet-out density of 1.05–1.10 g/cm³. The fused silica filler settles slowly; cartridges should be re-homogenized by rolling for 30 min after freezer storage because phase separation during shipment can alter the thixotropic index and dispense weight. The maximum continuous needle-dispense pressure at 25 °C is 2.5 bar; higher pressures can split filler agglomerates and cause valve leakage in closed-loop dispensing systems.
