| HS Code | 236365 |
| Property | Lead Frame Bonding Adhesive Electronic/EL Grade |
| Thermal Conductivity | 1.2 W/m·K |
| Electrical Conductivity | Non-conductive |
| Volume Resistivity | 10^12 Ω·cm |
| Dielectric Constant | 4.5 |
| Dielectric Strength | 15 kV/mm |
| Adhesion Strength | 1200 psi |
| Glass Transition Temperature | 150°C |
| Cure Temperature | 175°C |
| Cure Time | 60 minutes |
| Viscosity | 35000 mPa·s |
| Water Absorption | 0.2% |
| Operating Temperature Range | -55°C to 200°C |
| Shelf Life | 12 months at 5°C |
As an accredited Lead Frame Bonding Adhesive Electronic/EL Grade factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Lead Frame Bonding Adhesive, Electronic/EL Grade, supplied as a 50 mL syringe with sealed nozzle, ready for precise application. |
| Container Loading (20′ FCL) | 20′ FCL: packed in sealed drums/pails on pallets, secured, labeled, with MSDS available, for safe transport of electronic/EL-grade lead frame bonding adhesive. |
| Shipping | Ship as **UN 1133, Adhesives, Class 3, PG II**, with a **Flammable Liquid** label. Pack in approved containers, grounded during transfer, and protect from heat/ignition sources. Use proper shipping name: “Adhesives, containing flammable liquid.” Ensure segregation and transport documentation reflect the assigned packing group and any limited-quantity exemption if applicable. |
| Storage | Store in a cool, dry, well-ventilated area away from heat, sparks, and direct sunlight. Keep the container tightly sealed when not in use to prevent moisture contamination and solvent evaporation. Avoid contact with incompatible materials such as strong oxidizers. Ensure compliance with local regulations and maintain proper labeling. |
| Shelf Life | Shelf life is typically 6–12 months from manufacture when stored sealed, dry, at room temperature in original container. |
The release criterion for a QFN or DFN assembly line is not lap shear but post-cure die shear measured under MIL-STD-883J Method 5011.5, with acceptance thresholds typically between 6.0 kgf and 8.0 kgf for a 2.0 mm × 2.0 mm silicon die. Moisture sensitivity compliance is anchored to IPC/JEDEC J-STD-020D.1; packages classified as MSL 3 must be dry-packed within a 30°C/60% RH floor-life window after bake. At formulation level, the silver flake addition ratio is 78–82 wt% of total compounded adhesive, which yields a post-cure volume resistivity of ≤5×10−4 Ω·cm when tested by ASTM D257-14. Ionic purity for electronic-grade qualification is specified as extractable chloride <10 ppm, sodium <5 ppm, and potassium <5 ppm by MIL-STD-883 Method 5011.3.
On the die bonder, the adhesive is deposited with a time-pressure dispensing head fitted with a 22–27 gauge needle on a rotary indexing system running 25,000–35,000 UPH. Deposition mass is 0.8–1.8 mg per die, producing a bondline thickness of 15–30 µm after placement at 50–150 gf. Cure is carried out in a nitrogen tunnel at 175°C for 60 min with oxygen below 50 ppm to limit copper oxidation at the leadframe pad edge. Batch-to-batch variation in silver flake surface moisture shifts the nominal uncured viscosity from 8,000 cP to 12,000 cP at 25°C; incoming lots are therefore vacuum-dried at 70°C for 2 h before compounding, and any agglomerates larger than 20 µm are removed through a 400-mesh screen prior to syringe filling. Terminal packages include QFN-3×3, QFN-5×5, DFN2020-6, and DFN1610-6 for PMIC, RF switch, USB Type-C protection, and battery management modules. Pre-drying at 70°C for 4 h is required when ambient relative humidity exceeds 60%, and contact with amine-based molding compounds must be revalidated because premature edge cure can lower hot die shear at 260°C.
In discrete power packaging, the leadframe pad is not a passive carrier but a heat spreader with copper alloy thickness of 0.50–0.80 mm in DPAK and TO-220 formats, which places the thermal resistance budget on the die attach bondline. The qualification set includes JEDEC JESD22-A104-B thermal cycling from −65°C to +150°C for 1,000 cycles, JEDEC JESD22-A101-B biased humidity at 85°C/85% RH for 1,000 h, and UL 94 V-0 for molded package flame retardancy; thermal conductivity is measured by ASTM D5470-17 with a target above 8.0 W/m·K for conductive grades. The formulation addition ratio for this segment is 82–85 wt% silver flake, and the deposition mass is 1.5–2.5 mg for a 3.0 mm × 4.0 mm power MOSFET die, producing a bondline of 20–50 µm. Dispensing occurs on a heated stage at 80–100°C to bring viscosity below 8,000 cP, after which die placement at 200–300 gf is followed by snap cure at 200°C for 5 min. Laser profilometry checks die tilt after placement, and assemblies with tilt above 1.5° are rejected because wire bond shorting risk increases. X-ray inspection also rejects die attach regions where void area exceeds 5% because thermal impedance increases measurably at each additional percentage point of void area. Finished parts include TO-220 MOSFETs, DPAK power regulators, and IGBT modules for motor control and server VRM applications. Closed-loop volumetric compensation is required on the dispense head because uncured viscosity variation between 6,500 cP and 9,500 cP can shift deposition mass by ±10% across a single reel.
Bottom-side void formation in SMD LED packages is governed by solvent volatilization and silver flake settling on Ag-plated copper leadframes, not by die shear alone. The compliance framework includes IPC/JEDEC J-STD-020D.1 for reflow survival and UL 94 V-0 for the PPA or EMC housing; die shear is measured per MIL-STD-883 Method 5011.5, and lap shear after 48 h at 85°C/85% RH is checked by ASTM D1002-10. The low-warpage grade is dispensed at 0.4–0.8 mg per 1.0 mm × 1.0 mm LED die, with silver flake loading reduced to 75–80 wt% and residual solvent below 0.5 wt% to keep the bondline at 10–20 µm. High-speed die bonders using stamping transfer place dies at 15,000–25,000 UPH; the leadframe is plasma-cleaned before attach to maintain a silver surface energy above 40 mN/m. Cure is 150°C for 2 h in air, and any die attach grade containing amine-based accelerator is incompatible with the silicone encapsulation used downstream because premature crosslinking in the needle can increase dot height non-uniformity from ±5% to ±18% within 4 h. The mounted package must survive three reflow passes with a peak temperature of 260°C without delamination at the die attach fillet. Finished package types are SMD 2835, SMD 3030, and SMD 5050 LED emitters for backlight, horticultural lighting, and general illumination.
When the bonded leadframe enters contact smart card module lamination, the dominant failure mode shifts from thermal fatigue to film-substrate delamination after repeated bending and torsion. Applicable standards are ISO/IEC 7816-1 for card module dimensions and ISO/IEC 10373-1 for mechanical durability; the adhesive must survive 500 torsion cycles and 1,000 dynamic bending cycles without crack propagation from the die attach edge. The adhesive is used as a B-staged film with a thickness of 25–40 µm, covering 70–90% of the chip backside area; filler loading is 70–75 wt% silica or silver-coated glass, depending on whether electrical grounding is required. Reel-to-reel hot lamination is conducted at 120–150°C under 5–10 MPa for 20–40 min, after which the strip is die-cut and embedded into PVC, PET, or polycarbonate card bodies. Wafer backside dicing tape residue must be below 0.1 µg/mm² prior to lamination because organic residues reduce the B-staged adhesive wetting and create edge voids during module embedding. Finished formats include dual-interface smart card modules, SIM modules, eSIM modules, and contact-only banking card modules.
Autoclave exposure at 121°C/100% RH for 96 h under JEDEC JESD22-A102-C separates leadframe bonding adhesives that retain die shear from those that hydrolyze at the silver flake–resin interface. Optocoupler packages are additionally qualified to IEC 60747-5-5 for electrical isolation and UL 1577 for isolation voltage, with die shear measured after autoclave according to MIL-STD-883 Method 5011.5. Die attach for the emitter die uses 0.3–0.6 mg per 0.4 mm × 0.4 mm infrared LED die, a bondline of 10–18 µm, and filler loading of 70–75 wt%; the detector die may use a low-stress non-conductive grade with a bondline of 20–30 µm. The production line attaches dies on silver-plated copper leadframes with a multi-needle dispensing station, then cures at 150°C for 60 min before transfer molding at 175°C and 500–800 psi; post-mold cure is 175°C for 4 h. Die attach fillet extrusion beyond 0.1 mm from the die edge is rejected after mold deflash because it can bind with the mold compound and create a crack path during autoclave. Moisture absorption of the adhesive after 168 h at 85°C/85% RH must remain below 0.3 wt%, otherwise autoclave-induced delamination appears at the die edge rather than the leadframe surface. Finished units are SOP-4, DIP-4, and LSOP-4 optocouplers for isolated gate drivers, power supplies, and solid-state relays.
Palladium-coated copper leadframes used in automotive sensor and Hall-effect packages present a lower oxide growth rate but also a lower surface polarity than bare copper, narrowing the acceptable wetting envelope of low-bleed die attach adhesives. The qualification framework for underhood and chassis-mounted devices is AEC-Q100 Grade 1, including JEDEC JESD22-A104-B thermal cycling from −65°C to +150°C for 1,000 cycles and JEDEC JESD22-A103-C thermal shock; tensile properties are measured by ASTM D638-14, and die shear by MIL-STD-883 Method 5011.5. The adhesive is dispensed at a bondline of 20–40 µm with a filler loading of 78–82 wt%; for a 1.5 mm × 1.5 mm sensor die, the deposition mass is 0.6–1.1 mg. Vacuum-assisted dispensing is used in cavity packages to remove air bubbles trapped around the die edge; cure is 175°C for 30 min, followed by 150°C for 60 min post-cure to stabilize the glass transition temperature above 135°C by DSC. Published data for this specific surface polarity configuration is limited; release qualification should therefore include die shear after 1,000 h at 150°C rather than relying on room-temperature adhesion alone. Pre-drying at 70°C for 4 h is necessary when ambient relative humidity exceeds 60%; direct contact with silicone-based release agents on leadframe tape should be avoided because it can reduce die shear by more than 20% in this low-polarity surface condition. Terminal assemblies include manifold absolute pressure sensors, Hall-effect current sensors, and transmission speed sensors.
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Lead Frame Bonding Adhesive Electronic/EL Grade is a one-component, solvent-free epoxy system released for die-to-lead-frame and lead-frame-to-substrate attachment in discrete semiconductors, LQFP/QFN strip assemblies, and power modules where mobile ionic contamination must remain below wire-bond corrosion thresholds. The product is identified by the suffix EL; no separate numeric model code is published because the EL designation itself defines the contamination-control and outgassing profile. When dispensed from 10 mL syringes through a rotary positive-displacement pump fitted with a 22-gauge needle at 25 °C, the material forms a non-slump fillet with a wet bond line thickness of 20–40 µm under 0.4 N die placement force. Cure at 175 °C for 1 h in a nitrogen-atmosphere inline oven yields a cured adhesive with volume resistivity 1.5 × 10^12 Ω·cm by ASTM D257-14, lap shear on silver-plated copper alloy of 10.5–11.5 MPa by ASTM D1002-10, and glass transition temperature of 147–151 °C by ISO 11357-2:2020. Total hydrolyzable chloride after cure is controlled to <20 ppm by MIL-STD-883 TM 5011, and total mass loss is 0.07–0.08 % by ASTM E595-15. The grade is intended for electrically insulating bond lines, not for die-backside conduction; designs requiring thermal conductivity above 2.0 W/m·K should evaluate silver-filled die-attach materials instead.
Dispensing behavior is governed by shear-thinning rheology and the temporal stability of the dot after deposition. At 25 °C and 10 s^-1, apparent viscosity is 38–46 Pa·s; thixotropic index between 1 s^-1 and 10 s^-1 is 3.2–4.0. This property set prevents starved fillets on 100 µm pitch Ag-spotted copper alloy lead frames but can cause tailing if needle retraction delay is shorter than 35 ms. Production dispense trials on 208-lead LQFP strips with a closed-loop positive-displacement pump at 12 mm/s shot speed and shot size 0.60 ± 0.05 mg showed an increase in missing-dot count when the feed reservoir temperature drifted above 28 °C because viscosity at 10 s^-1 fell below 32 Pa·s and fillet wicking onto the adjacent lead frame tie bar exceeded 150 µm. Void formation is suppressed by holding the lead frame stage at 150 °C prior to die placement; at stage temperatures below 120 °C, adhesive steady-shear viscosity remains above 80 Pa·s and trapped air pockets can remain after the adhesive reaches the gel point at 175 °C, which is 3.2 min by ISO 11357-5:2013 cure kinetics.
Void content after cure is measured by scanning acoustic microscopy at 30 MHz and corrected for lead frame attenuation. In a 64-lead QFP process with 0.45 N die placement force, average void area increased from 1.2 % to 3.8 % when dispense-to-placement delay exceeded 12 s at 25 °C and 55 % RH. This is attributed to partial skinning of the dot surface, which prevents wetting of the die backside. At ambient RH above 60 %, syringes must be warmed to 25 °C for 1 h before opening to prevent condensation on the uncured adhesive, and any open syringe must be consumed within 72 h to maintain the specified gel time.
Die placement is performed on a die bonder with closed-loop bond force control and a heated workpiece holder. At placement force 0.35–0.50 N, the wet bond line reaches 20–40 µm; placement force below 0.30 N creates a bond line thicker than 50 µm and can leave a resin-rich center after die tilt correction exceeds 1.0°. Placement force above 0.65 N on 70 µm thick die can squeeze the adhesive onto the active surface near the die edge, producing a fillet greater than 150 µm and causing mold compound fill interference. On a production line using 16 mm singulated lead frames, the maximum practical strip index speed is 85 mm/s before die pick-and-place loses synchronization with dispense due to dot-to-dot distance variation of ±0.10 mm. These values are based on machine capability studies with a rotary positive-displacement dispenser and vision-guided die bonder; they are not transferable to all equipment without a gage repeatability study.
Bare copper lead frames require surface preparation before bonding because the adhesive’s organic acid adhesion promoter competes with cuprous oxide growth. A plasma clean with argon-oxygen at 200 W for 180 s or a microetch producing surface roughness Ra 0.4–0.8 µm is required; without this treatment, lap shear on bare copper decreases by 20–30 % under ASTM D1002-10. The product is incompatible with amine-based accelerators and with residual amine-containing mold release films; free amines attack the latent hardener and reduce the gel time from 3.2 min at 175 °C to 1.6 min, while pot life at 25 °C drops from 72 h to 8 h.
Batch-to-batch variance is controlled by ion chromatography and rheometry on each production lot. Table 1 lists three-lot in-process data for a 10 L planetary-mixed batch. These values are control ranges, not guaranteed product specifications. Lap shear values are generated after cure at 175 °C for 1 h on silver-plated copper coupons roughened to Ra 0.5 µm.
| Test | Method | Lot A | Lot B | Lot C |
|---|---|---|---|---|
| Apparent viscosity at 10 s^-1, 25 °C | ISO 3219:2013 | 42 Pa·s | 44 Pa·s | 46 Pa·s |
| Thixotropic index 1 s^-1/10 s^-1 | ISO 3219:2013 | 3.4 | 3.6 | 3.8 |
| Lap shear on Ag-plated Cu | ASTM D1002-10 | 11.2 MPa | 10.7 MPa | 11.0 MPa |
| Glass transition temperature by DSC | ISO 11357-2:2020 | 148 °C | 151 °C | 147 °C |
| Extractable chloride | MIL-STD-883 TM 5011 | 15 ppm | 17 ppm | 16 ppm |
| Total mass loss | ASTM E595-15 | 0.07 % | 0.08 % | 0.07 % |
Cure kinetics by differential scanning calorimetry at 5, 10, 15, 20 °C/min per ISO 11357-5:2013 give an Ozawa activation energy of 75 kJ/mol and an autocatalytic reaction model. Gel time at 175 °C is 3.2 min; at 150 °C it is 9.8 min. A snap-cure profile at 200 °C for 8 min is feasible for thin bond lines, but the die bonder cure-oven interface must hold dwell time to ±15 s because gel point at 200 °C occurs near 1.4 min. The exothermic peak cure is 385 J/g for the catalyzed formulation, and the fully cured glass transition is 147–151 °C.
For ovens with a tunnel length of 5.0 m and a belt speed of 0.18 m/min, the residence time at 175 °C is 25 min; the actual cure cycle must therefore include a ramp zone that begins at 120 °C and holds for 5 min to prevent void expansion from the diluent-free resin. The adhesive does not contain a reactive diluent, so the linear cure shrinkage by thermomechanical analysis per ASTM E831-19 is 0.35 %. This low shrinkage is critical for die with active area extending to the edge; higher-shrinkage epoxies have created die edge cracks during cool-down from 175 °C to 25 °C when the die thickness is <75 µm.
After transfer molding, moisture sensitivity is evaluated at package level using IPC/JEDEC J-STD-020E preconditioning: 85 °C / 85 % RH for 168 h, followed by three reflow passes at 260 °C peak. The adhesive retains ≥ 80 % of initial die shear after this sequence on 8 × 8 mm die with 25 µm bond line. If the package has a vented cavity or the adhesive fillet is exposed before molding, dry storage at <30 % RH for 24 h prior to wire bonding is required to avoid pad oxidation from moisture evolved from the adhesive.
For package designs where thermal and electrical performance are prioritized differently, the Electronic/EL grade is distinct from two common alternatives. Table 2 compares representative control values using identical test methods. The EL grade is not selected for die-backside conduction or for thermally conductive interfaces requiring > 2.0 W/m·K; silver-filled die-attach paste is used for those designs. Silicone-based thermal adhesives provide greater bond line compliance but lower lap shear and higher total outgassing, limiting their use in hermetic or wire-bonded packages.
| Property | Test method | EL grade | Silver-filled die-attach | Silicone thermal adhesive |
|---|---|---|---|---|
| Volume resistivity after cure | ASTM D257-14 | 1.5 × 10^12 Ω·cm | 5 × 10^-4 Ω·cm | 3 × 10^14 Ω·cm |
| Lap shear on Ag-plated Cu | ASTM D1002-10 | 10.5–11.5 MPa | 6.5–8.0 MPa | 1.2–2.5 MPa |
| Thermal conductivity | ASTM E1530-19 | 0.9 W/m·K | 2.5 W/m·K | 1.0 W/m·K |
| CTE below Tg | ASTM E831-19 | 42 ppm/°C | 38 ppm/°C | 250 ppm/°C |
| Total mass loss | ASTM E595-15 | 0.07–0.08 % | 0.20–0.35 % | 0.5–1.2 % |
| Extractable chloride | MIL-STD-883 TM 5011 | <20 ppm | <50 ppm | 100–150 ppm |
The principal difference from general-purpose electronic assembly epoxies is the release criterion for extractable chloride; many structural epoxies allow 50–100 ppm, whereas the EL grade is released only below 20 ppm. In high-humidity bias testing, this difference translates to surface insulation resistance higher than 10^8 Ω after 168 h, compared with 10^6–10^7 Ω for a standard electronic epoxy. For lead frames with exposed pad and thin bond line, the lower ionic content reduces the probability of galvanic corrosion between silver-plated lead frame and aluminum wire bond pad at the wedge bond interface.
Surface insulation resistance after 168 h at 40 °C / 90 % RH with 10 V DC bias on an IPC-B-25 comb pattern is 2.8 × 10^8 Ω by IPC-TM-650 2.6.3.3. Electrochemical migration testing at 85 °C / 85 % RH for 1,000 h with 50 V DC on a 0.2 mm gap shows no dendritic growth under 200× inspection. The cured extract conductivity is <4 µS/cm in deionized water after 24 h at 85 °C. The uncured resin contains no intentionally added lead, cadmium, mercury, hexavalent chromium, PBB, or PBDE; compliance is verified by IEC 62321-5:2013 for cadmium and IEC 62321-7-2:2017 for hexavalent chromium. REACH SVHC content is below 0.1 % w/w per EC 1907/2006.
The inorganic filler has a median particle size 2.5 µm and maximum 12 µm by laser diffraction per ISO 13320:2020. The filler is silane-treated in a heated high-shear mixer to reduce water uptake after cure to 1.2 % after 24 h boiling water immersion by ASTM D570-98(2018). This is important for lead frames with exposed pad packages, where moisture absorbed at the bond line during reflow can generate vapor pressure and popcorn cracking. The cured network has a crosslink density of 2.6 × 10^-3 mol/cm³ calculated from the rubbery plateau storage modulus by ASTM E1640-18. The coefficient of thermal expansion below Tg is 42 ppm/°C by ASTM E831-19; above Tg it is 118 ppm/°C.
Fillet geometry is controlled by the needle inner diameter, the adhesive’s yield stress, and die placement squeeze flow. With a 22-gauge needle, a dispensed dot of 0.60 mg produces a wet fillet with contact angle 35–45° on silver-plated copper after 3 s of die placement. Contact angle values above 50° occur when the lead frame silver spot has been contaminated with die-pickup tape residue or organic solderability preservative; contact-angle control is therefore measured with a goniometer on each lot prior to die bonding. A fillet height above 40 µm can contact the mold compound flow front and create incomplete mold fill at 45 °C mold temperature and 10 MPa transfer pressure. In QFN packages with exposed pad, a low fillet height of <20 µm is required to prevent mold bleed onto the pad surface.
The cured adhesive is rated for continuous operating temperature 150 °C based on thermogravimetric analysis at 5 % mass loss in air at 345 °C per ASTM E1131-08. At 200 °C for 1,000 h, lap shear retention on silver-plated copper decreases to 65 % of initial. This is the upper boundary for power packages with junction temperatures above 175 °C; for such applications, polyimide-based die attach systems are usually evaluated.
The cured adhesive must provide a stable ultrasonic energy path without acting as a dampening layer or causing die deflection. Dynamic mechanical analysis by ASTM E1640-18 gives a storage modulus of 8.5 GPa at 25 °C and 3.4 GPa at 175 °C. This modulus supports 0.8 mil aluminum wire wedge bonding on 70 µm thick die in 100-lead LQFP packages without die cratering, provided the adhesive fillet does not encroach on the bond pad by more than 50 µm measured at 200× optical inspection. Adhesives with storage modulus above 12 GPa at 25 °C have exhibited cratering in the same package type, so the EL grade’s upper modulus limit is a critical control parameter.
Outgassing during the wire bonding stage is limited to 0.05 % total volatile condensable material after 125 °C for 24 h by ASTM E595-15. This reduces the risk of oxide growth on palladium-coated copper wire bond pads at 220–250 °C wedge bonding. For packages with exposed pad or cavity construction, a 1 h bake at 175 °C in nitrogen before wire bonding is recommended when the adhesive has been stored longer than 6 months or exposed to 60 % RH for more than 24 h.
Reliability in thermal cycling is influenced by the coefficient of thermal expansion mismatch between the cured adhesive, copper alloy lead frame, and silicon die. After 500 cycles from -65 °C to 150 °C per JESD22-A104, die shear retention on Ag-plated copper remains ≥ 80 % for a 5 × 5 mm die with 25 µm bond line. In highly accelerated stress testing at 130 °C, 85 % RH, and 2 atm for 96 h per JESD22-A110, the bond line exhibits no delamination greater than 10 % of die area when the lead frame paddle is designed with a drain hole. Published data for bond lines below 20 µm in this specific configuration is limited; package-level qualification with actual die size, lead frame alloy, and mold compound is required. For bare copper lead frames, the adhesion promoter system is not effective in sulfur hexafluoride plasma environments; argon or argon-oxygen plasma must be used instead. Unopened syringes are stored at -20 °C and shipped with dry ice; shelf life is 6 months from date of manufacture. At 5 °C, shelf life is 30 days. Before use, syringes are thawed at 25 °C for 1 h in a dry-nitrogen cabinet with dew point below -30 °C; this prevents condensation. Bulk jars must not be opened in uncontrolled cleanroom humidity because a single 10 min exposure at 65 % RH increases moisture absorption of the uncured resin by 0.3 wt%, which can increase void area after cure by 0.8 %.
