| HS Code | 691096 |
| Chemical Composition | Electronically pure epoxy resin with latent hardener |
| Appearance | Smooth paste or liquid, typically silver or black |
| Viscosity | 10000–20000 mPa·s at 25°C |
| Specific Gravity | 1.5–2.0 g/cm³ |
| Curing Temperature | 150–180°C |
| Curing Time | 30–60 minutes at curing temperature |
| Storage Temperature | 2–8°C in sealed container |
| Shelf Life | 6 months from date of manufacture |
| Volume Resistivity | ≥1×10¹⁴ Ω·cm |
| Dielectric Strength | ≥20 kV/mm |
| Glass Transition Temperature | ≥130°C |
| Coefficient Of Thermal Expansion | Below Tg: 25–40 ppm/°C; above Tg: 100–130 ppm/°C |
| Thermal Conductivity | 0.4–1.0 W/m·K |
| Outgassing | Total mass loss <1.0% |
| Ionic Contamination | Chloride ≤10 ppm, Sodium ≤5 ppm, Potassium ≤5 ppm |
| Water Absorption | <0.5% after 24 hours at 25°C |
| Die Shear Strength | ≥1.5 kg per 2×2 mm die |
| Service Temperature Range | -55°C to +150°C |
As an accredited Chip Bonding Adhesive Electronic/EL Grade factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Chip Bonding Adhesive Electronic/EL Grade, supplied in a sealed 5-gram syringe, ready for precise dispensing in electronics assembly. |
| Container Loading (20′ FCL) | Chip Bonding Adhesive Electronic/EL Grade is packed in sealed drums, loaded as a 20′ FCL for safe, secure transport. |
| Shipping | Ship by ground freight only, away from heat, sparks, and direct sunlight. Keep containers tightly sealed and upright in approved packaging to prevent leakage. Ensure proper hazard labeling and documentation. Avoid moisture contamination. Use secondary containment during transport. Follow local, national, and international regulations for adhesive and electronic-grade chemical shipment. |
| Storage | Store Chip Bonding Adhesive Electronic/EL Grade in a cool, dry, well-ventilated area away from heat, sparks, and direct sunlight. Keep the container tightly sealed to prevent moisture contamination. Maintain temperatures between recommended limits, typically 2–8°C if indicated. Avoid incompatibles and ensure secondary containment to prevent spills. Follow manufacturer label instructions. |
| Shelf Life | Store unopened at room temperature; shelf life is six months from manufacture date when kept in a sealed container. |
Silver flake-filled one-component epoxy chip bonding adhesive is introduced into discrete power packaging lines as a replacement for high-lead solder die attach on bare copper, silver spot-plated, and Ni/Pd/Au-finished leadframes. On a rotary die bonder with a positive-displacement dispensing pump and a needle diameter of 0.25 mm to 0.41 mm, the adhesive is deposited as a single dot or cross pattern onto a leadframe pad held at 70°C to 90°C. Die placement force is controlled between 0.5 N and 1.2 N; excessive squeeze-out below a 0.15 mm bondline can push filler-depleted resin beyond the die edge and contaminate adjacent wire-bond pads. For a 2 mm × 2 mm silicon MOSFET die, hot die shear acceptance after 175°C cure for 60 min is normally set above 2.0 kgf when tested in accordance with MIL-STD-883 Method 2019.9. The cure profile is commonly staged at 100°C for 30 min to suppress solventless resin bleed, followed by 175°C for 60 min in a forced-air or nitrogen tunnel oven with zone uniformity of ±2°C. Acceptable total filler loading for this application ranges from 80 wt% to 86 wt% silver flake with a D50 between 5 µm and 10 µm; below 80 wt% bulk resistivity rises above 1 × 10⁻⁴ Ω·cm and above 86 wt% the viscosity exceeds the stable dispense window of 10,000 mPa·s to 50,000 mPa·s at 25°C.
Field data from automatic lines show batch-to-batch shifts in silver flake surface treatment can alter viscosity by ±15% and change hot die shear by ±10%. Resin bleed beyond 0.2 mm is the dominant cause of non-stick on pad in subsequent wire bonding; this failure is reduced by keeping the leadframe temperature at 80°C to 85°C and by specifying a thixotropic index of 3.5 to 5.5 measured at 1 rpm/10 rpm. Biased humidity testing at 85°C/85% RH with 10 V DC following JESD22-A101-derived conditions requires chloride below 10 ppm, sodium below 5 ppm, and total extractable halogens below 50 ppm by ion chromatography. If silver migration is observed, the root cause is usually residual ionic catalyst or incomplete cure; the corrective action is to raise cure temperature by 5°C or extend cure time by 10 min, not to increase silver flake loading. The final package types—TO-220, TO-252, DFN5×6, and PQFN—achieve lead-free status without invoking solder exemptions under Directive 2011/65/EU and (EU) 2015/863.
| Parameter | Acceptance limit | Method |
|---|---|---|
| Hot die shear after 175°C cure, 2 mm × 2 mm Si die | > 2.0 kgf | MIL-STD-883 Method 2019.9 |
| Bulk resistivity | < 1 × 10⁻⁴ Ω·cm | four-point Kelvin probe on cured film coupon |
| Extractable chloride | < 10 ppm | IPC-TM-650 2.3.28 |
| Extractable sodium | < 5 ppm | IPC-TM-650 2.3.28 |
| Total extractable halogens | < 50 ppm | IPC-TM-650 2.3.28 |
| Total mass loss | < 0.5% | ASTM E595-15 |
| Collected volatile condensable material | < 0.1% | ASTM E595-15 |
In chip-on-board assembly of microcontrollers, ASICs, and sensor-interface die onto FR-4 or BT laminate, the chip bonding adhesive is applied directly beneath the die without a hermetic cavity; consequently, ionic purity and hydrolysis resistance rather than bulk strength determine field reliability. Dispensing is executed with a rotary screw pump and a 0.20 mm to 0.30 mm needle on substrates finished with ENIG, immersion silver, or plated gold; OSP copper is avoided because the azole coating can be displaced by adhesive wetting agents and leave bare copper that catalyzes die shear decay. The dot volume is held between 0.05 mm³ and 0.20 mm³ to produce a fillet height below 0.10 mm. Cure on FR-4 is reduced to 120°C for 90 min or 135°C for 60 min when the substrate Tg is 130°C; higher-temperature snap cures can warp 0.8 mm and thinner boards beyond wire-bonding flatness limits. Aluminum wire of 25 µm diameter is then wedge-bonded to the die pads; adhesive bleed above 0.1 mm creates non-stick on pad defects because the fillet tail covers the aluminum bond pad area. The final electronic control unit for keyboard, mouse, or appliance modules is subjected to JEDEC JESD22-A104 condition B cycling from -55°C to 125°C; die shear after 500 cycles must retain at least 70% of initial value. Chloride and sodium limits are tighter than in fully encapsulated packages because the exposed die passivation is the only barrier against ionic migration on the board surface.
For visible LED die attach on silver-plated copper leadframes, ceramic submounts, and COB light engine boards, the silver-filled chip bonding adhesive must balance thermal transport against optical side-wall cleanliness. A dispense robot with a 33-gauge needle deposits a bondline of 5 µm to 15 µm after placement; bondline tilt across a 0.5 mm × 0.5 mm LED chip is held below 10 µm to avoid color shift and hot-spot formation. Cure at 150°C for 30 min to 60 min is preferred because long exposure above 180°C degrades the silver plating on the leadframe through sulfur-assisted oxidation. Thermal conductivity of the cured adhesive is specified between 3 W/m·K and 8 W/m·K; filler loading near 85 wt% produces the upper end but also raises the modulus enough to crack fragile GaN-on-sapphire corners during ultrasonic vibration. Discoloration failures in 2835 and 5050 SMD packages are minimized by ensuring extractable sulfur in the adhesive remains below 50 ppm and by excluding sulfur-cured rubber gaskets from dispensing lines. Thermal shock per JESD22-A104 condition C from -40°C to 125°C for 100 cycles is followed by wire-pull and die-shear testing; die shear acceptance for 1 mm² die is commonly set at 1.0 kgf to 1.5 kgf.
Low-outgassing chip bonding adhesive for MEMS absolute pressure sensors, accelerometers, and optical proximity sensors is dispensed as a controlled-volume fillet that must not exceed 20% of the die sidewall height, because any adhesive rise onto the movable proof mass alters resonance and sensitivity. The process operates at placement force below 0.3 N to protect released MEMS structures; die tilt is kept below 0.5°, which on a 1 mm die corresponds to 8.7 µm of vertical offset. A two-step cure at 100°C for 30 min and 150°C for 30 min avoids exceeding the 160°C exposure limit typical for parylene-coated or polymer-sealed MEMS. Outgassing per ASTM E595-15 is controlled to total mass loss below 0.5% and collected volatile condensable material below 0.1% for pressure sensor cavities that require stable vacuum reference over the automotive life. The final product—tire pressure monitoring sensors, manifold absolute pressure sensors, and industrial differential transducers—is qualified under JESD22-A104 condition G from -40°C to 150°C; die shear after 1000 cycles must remain above 1.5 kgf for a 2 mm × 2 mm glass-frit-passivated silicon sensor die.
Under-hood electronic modules such as transmission control units, electric power steering controllers, and knock sensors subject die attach to continuous operation between -40°C and 150°C; lead-free solder joints often show creep-fatigue at these extremes, whereas silver-filled epoxy chip bonding adhesive with a cured glass transition temperature above 180°C maintains die shear after thermal cycling. The adhesive is dispensed onto die pads of ceramic substrates or copper leadframes, then cured at 150°C for 60 min and post-cured at 175°C for 15 min to drive conversion above 95% as measured by differential scanning calorimetry. Bulk filler loading is tuned to 82 wt% to 84 wt% silver flake to obtain volume resistivity near 5 × 10⁻⁵ Ω·cm while retaining enough resin to avoid brittle fracture under rapid temperature change. Coefficient of thermal expansion of the cured network is typically 35 ppm/°C to 45 ppm/°C below Tg, which is higher than copper at 17 ppm/°C; interfacial stress therefore concentrates at fillet boundaries. Qualification includes 1000 cycles of JEDEC JESD22-A104 condition G from -40°C to 150°C, with die shear above 2.0 kgf for a 2 mm × 2 mm die and no soldermask delamination beyond 0.1 mm from the bondline.
Production-scale failures occur as cohesive fracture through the adhesive under cold-cycle pull because the modulus at -40°C rises above 6 GPa and concentrates tensile stress at the fillet toe. Formulators lower the crosslink density with a reactive flexibilizer; addition of 2.5 wt% of an elastomer-modified epoxy lowers the room-temperature modulus by approximately 20% but reduces hot die shear by 10% to 15%, requiring re-balancing of filler loading. A more robust line fix is to maintain the initial die shear target and specify a maximum filler settling rate of 5% by volume after 24 h at room temperature in the dispense reservoir, because settled silver flake near the needle tip produces inconsistent viscosity and variable fillet geometry. Aged adhesion is also checked with 85°C/85% RH biased moisture testing per JESD22-A101; failure analysis of under-hood modules shows silver migration at the adhesive-to-copper interface only when extractable chloride exceeds 10 ppm. Final qualification for the transmission control module requires all die attach regions to pass 1000 cycles of power temperature cycling from -40°C to 150°C with no change in RDS(on) greater than 10%.
Submount attach for 400G and 800G optical transceivers demands a chip bonding adhesive that does not generate lens-fogging condensate during device operation or reflow. Laser diodes, photodiodes, and thermoelectric cooler submounts are placed on alumina or silicon optical benches with a die bonder alignment accuracy of ±10 µm; cure is performed at 120°C for 60 min to 120 min because higher temperatures shift the aligned elements through asymmetric thermal expansion. The adhesive is specified with total mass loss below 0.5% and CVCM below 0.1% per ASTM E595-15; in practice, transceiver module builders tighten CVCM to below 0.05% for hermetically sealed optical cavities. Bondline thickness is controlled to 10 µm ± 2 µm to minimize z-axis displacement of the laser stripe relative to the lens. A low-stress filler system with 70 wt% to 75 wt% silver flake is used where electrical conductivity is required, accepting a higher volume resistivity of 10⁻³ Ω·cm to reduce thermal mismatch stress. The final TOSA/ROSA assemblies are tested under JEDEC JESD22-A104 condition C from -40°C to 125°C; die shear adhesion must remain above 1.0 kgf for 0.5 mm × 0.5 mm laser diodes after 500 cycles.
RF and millimeter-wave GaAs/GaN die attach for low-power buffer amplifiers uses silver-filled chip bonding adhesive only where DC contact and thermal load are below approximately 0.5 W/mm², because bulk resistivity of 10⁻⁴ Ω·cm is several orders above solder metallurgy and may degrade gain at millimetre-wave frequencies if the die backside path is part of the matching network.
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Chip Bonding Adhesive Electronic/EL Grade, model CB-EL-4100, is formulated as a single-component, silver-filled epoxy die-attach paste for discrete semiconductor packages, chip-on-board assemblies, and optoelectronic sub-mounts where controlled ionic purity and low outgassing are design constraints. The material is supplied in 5 cc, 10 cc, and 30 cc syringes with moisture-barrier caps, and the uncured adhesive is stored at −40°C to preserve latent catalyst activity. Unlike general-purpose electronic adhesives, the EL grade uses a low-hydrolyzable-chloride resin matrix and a narrow-cut silver flake filler system to reduce bondline void formation during cure. The uncured material is a thixotropic paste with a specific gravity of 3.5 ± 0.2 and a filler content of 72 ± 2 wt%; these values are part of the material identity block aligned with IPC-SM-817A. Published data for this specific CB-EL-4100 configuration is limited to the manufacturer’s certificate of analysis, but the ranges shown here fall within commonly accepted electronic-grade die-attach specifications.
Rheological measurements per ASTM D2196-20 at 25°C with a Brookfield CP52 spindle at 5 rpm typically yield viscosity from 18,000 cP to 35,000 cP. The thixotropic index, calculated as the ratio of viscosity at 0.5 rpm to viscosity at 5 rpm, is 4.0 to 6.0. This pseudoplastic response permits dispensing through 0.20 mm to 0.33 mm internal-diameter needles while retaining adequate fillet height after die placement. On an 8 h production shift at 25 ± 2°C, viscosity drift is maintained below 15% when the paste is covered from ambient moisture. These limits are intended for closed-loop dispense systems with vision alignment rather than manual hand-syringe application.
Void formation in the cured bondline follows two regimes: entrapped air from high-speed dispensing shear and volatile evolution from epoxy homopolymerization. The first is minimized with a tapered dispense tip, a retract height of 0.1 mm to 0.3 mm, and a delay of 20 ms to 40 ms after dot placement. The second is controlled by avoiding cure temperatures above 175°C when the substrate or die has a large vented cavity. On a 200 mm chip-on-board line with a rotary positive-displacement pump and 25 G needle, wet fillet width is controlled between 50 µm and 80 µm. A 15% viscosity drift increases fillet height variation by approximately 2×, which is detectable by laser height profilometry before cure.
Ionic cleanliness is controlled because mobile chloride and alkali ions can accelerate bondpad corrosion and alter surface leakage currents under biased humidity. Extractable chloride is specified at ≤10 ppm, sodium at ≤5 ppm, potassium at ≤5 ppm, and ammonium at ≤5 ppm by aqueous extraction and ion chromatography referenced to MIL-STD-883 Test Method 5011.3. The same method is used for production lot acceptance of high-reliability microelectronic materials; values for standard industrial epoxy are often uncontrolled and may exceed 50 ppm extractable chloride.
On automated die-attach lines, the paste is dispensed with positive-displacement pumps or auger valves onto leadframes, ceramic substrates, or pre-molded packages. Needles with internal diameters from 0.20 mm to 0.33 mm are used; placement force is typically 0.5 N to 1.0 N for die sizes below 5 mm × 5 mm. Too little placement force produces incomplete wetting of the die backside, while excessive force can squeeze the bondline below 15 µm and increase the risk of die edge contact with filler particles. C-mode scanning acoustic microscopy on assembled parts has shown void area below 2% when the paste is dot-dispensed in a star pattern rather than a single center dot; published data for larger die configurations is limited. The material is incompatible with amine-based flux residues and amine-containing surface activators because these species accelerate the latent curing reaction at the needle tip, causing idle-time clogging within 10 min. Packages with substrate moisture content above 0.10 wt% should be pre-baked at 125°C for 2 h to avoid interfacial steam voids during cure.
The primary difference is the combined low outgassing and low ionic impurity envelope. Outgassing tested per ASTM E595-15 at 125°C and pressure below 5 × 10⁻⁵ torr for 24 h yields total mass loss ≤ 0.30% and collected volatile condensable material ≤ 0.05%. Conventional quick-cure die-attach epoxies may show TML above 0.50% and CVCM above 0.10% under the same test, which is sufficient to deposit transparent films on LED optics or MEMS mirrors. The EL grade also restricts organosiloxane additives and low-molecular-weight epoxy diluents that are present in general-purpose chip adhesives; these substances are a known source of vapour-phase contamination after thermal aging.
Mechanically, the cured network is formulated for a glass transition temperature of 130°C to 145°C by differential scanning calorimetry per ASTM E1356-08 after a full cure of 175°C for 60 min. This Tg is higher than many flexible reworkable adhesives but lower than rigid aromatic high-Tg die attach materials. The higher Tg reduces creep at wirebonding temperatures, but the coefficient of thermal expansion below Tg remains between 35 ppm/°C and 45 ppm/°C, which is intentionally above bare silicon to avoid excessive die bow on thin-die packages. In contrast, many standard silver-glass die attach grades have CTE values below 30 ppm/°C but require sintering temperatures above 400°C, making them unsuitable for organic laminates and pre-molded packages.
Table 1. Comparative property matrix for CB-EL-4100 Electronic/EL Grade versus standard die-attach epoxy and industrial bonding epoxy.
| Property | CB-EL-4100 EL Grade | Standard die-attach epoxy | Industrial bonding epoxy |
|---|---|---|---|
| Extractable Cl⁻ | ≤10 ppm | ≤50 ppm | not controlled |
| TML per ASTM E595-15 | ≤0.30% | ≤0.50% | often ≥1.0% |
| CVCM per ASTM E595-15 | ≤0.05% | ≤0.10% | not controlled |
| Die shear at 25°C on bare copper per MIL-STD-883 TM 2019.7 | ≥12 MPa | ≥8 MPa | ≥5 MPa |
| Thermal conductivity by ASTM E1461-13 | 2.2–2.8 W/m·K | 1.5–2.0 W/m·K | 0.4–0.8 W/m·K |
| Maximum continuous use temperature | 200°C | 175°C | 120°C |
The filler system consists of surface-treated silver flakes with a laser diffraction D50 of 8 ± 2 µm and D90 of 18 ± 3 µm when measured per ISO 13320-1:2020. The flake surface treatment controls particle packing and prevents rapid moisture uptake when the paste is thawed in a humid cleanroom. A Hegman grind gauge indicates no discrete particles above 25 µm, which is relevant when bondline thickness is targeted at 20 µm to 40 µm. Filler settling during syringe storage is controlled by the thixotropic structure; after 14 days of horizontal storage at 25°C, the top-to-bottom silver fraction variation is less than 2 wt%, based on thermogravimetric analysis of separated syringe sections.
Cure kinetics by nonisothermal differential scanning calorimetry per ASTM E2160-04 at 10°C/min show an onset exotherm near 112°C and a peak exotherm between 150°C and 165°C. The total heat of reaction is 180–220 J/g of resin matrix. At 150°C, a box-oven cure of 30 min produces conversion above 95%; at 175°C, 10 min is sufficient for leadframe strip processes. The 200°C snap-cure condition of 5 min is permitted only for leadframe-based packages with die size below 3 mm × 3 mm because the thermal lag across a larger die can leave the bondline center undercured. Under-cure is detected as reduced hot die shear strength and increased moisture sensitivity after pressure-cooker testing at 121°C/100% RH for 96 h.
Gold, silver, palladium, and bare copper substrates are compatible when they are free of organic transfer film and have a surface roughness Ra between 0.2 µm and 0.4 µm. Nickel-palladium-gold leadframes require an oxide-free finish; nickel oxide above 3 nm reduces initial die shear by 20–30% on pull tests. On silver-plated copper, the adhesive wetting angle after placement is below 30° at 25°C, measured by contact-angle goniometry on a silicon die substitute. Published data for gold-bump interconnects with this specific CB-EL-4100 formulation is limited; bump height coplanarity should be maintained below ±5 µm to avoid localized voiding.
Dynamic mechanical analysis in three-point bending at 1 Hz after cure gives a storage modulus at 25°C of 4.5 GPa to 6.5 GPa. At 175°C, the modulus falls below 0.4 GPa because the crosslinked epoxy moves above its glass transition. This drop permits stress relaxation during cool-down from cure, but it also limits the adhesive bondline in applications where die-attach materials must retain stiffness during gold-wire thermosonic bonding. The use of a lower CTE silver-glass or a rigid cyanate ester adhesive would be indicated only if die bow data show unacceptable warpage; published data for CB-EL-4100 in large-die formats is limited.
Thin silicon die below 100 µm impose a ramp-rate constraint that overrides the usual snap-cure preference. If the assembly enters an oven already held at 175°C, the die surface and the uncured adhesive can heat at rates exceeding 10°C/s, generating thermal gradients that crack the thinned silicon. For such configurations, the cure profile should include a controlled ramp from 25°C to 150°C at no more than 5°C/min, followed by a 30 min soak at 150°C. When the process transfers to 175°C for higher throughput, the ramp segment must be retained until the strip temperature reaches 120°C. This procedural boundary is derived from die-break strength measurements and is not a cure kinetics limitation of the adhesive itself.
After cure, die shear strength measured by MIL-STD-883 Test Method 2019.7 at 25°C is typically ≥12 MPa on bare copper leadframes and ≥8 MPa on silver-plated copper. After 1000 h of storage at 200°C in air, retention is at least 70% of the initial value. After JEDEC JESD22-A113F moisture sensitivity level 3 preconditioning with a 260°C peak reflow, the material typically retains ≥80% of initial room-temperature die shear. Failure modes should be cohesive within the adhesive or mixed at the copper interface; interfacial fracture between the silver flake and die backside indicates incomplete cure or contamination and is cause for lot rejection.
Biased humidity testing at 85°C/85% RH for 1000 h on interdigitated comb patterns with 0.25 mm spacing has shown leakage current stability below 1 nA when the adhesive is fully cured; extractable chloride above 10 ppm produces dendritic silver migration under the same conditions. For LED submount assemblies, outgassing per ASTM E595-15 is not sufficient to quantify in situ lens clouding; functional life testing at 85°C/85% RH for 1000 h is used. Published data for CB-EL-4100 in white-LED packages is limited; therefore, cavity packages should undergo a sealed mirror reflectivity test before production release.
Frozen storage at −40°C in unopened syringes preserves a shelf life of 12 months. Sealed cartridges are thawed at 25°C for 4 h before use; more than 3 freeze-thaw cycles are not recommended because flake settling and moisture ingress can shift viscosity by more than 20% and increase extractable chloride above the 10 ppm limit. Production lots are released against the MIL-STD-883 Test Method 5011.3 ionic cleanliness limit, uncured viscosity by ASTM D2196-20, and die shear on copper coupons by MIL-STD-883 Test Method 2019.7. Out-of-family lots with DSC peak exotherm drift greater than ±5°C or die shear below the internal minimum are quarantined. This release protocol follows ISO 9001:2015 Clause 8.6, not visual inspection alone.
