COOLTHERM ME-525
Harmonization Code : 3910.00.00.90 | Silicones in Primary Forms; Others
Main features
- 6,000 cP High-Purity Capillary Underfill
- 30-Minute 150 deg C Cure
- 120 deg C Tg
Product Description
CoolTherm® ME-525 Underfill Encapsulant is a high-purity, semiconductor-grade, one-part epoxy underfill developed for flip-chip device encapsulation. The black, low-viscosity liquid has a typical 6,000 cP viscosity at 25°C, 36-hour working life at 25°C, and five-minute gel time at 150°C. For the documented capillary-flow process, the substrate is preheated to 100°C, the underfill is dispensed as a corner-dot extrusion, and the material is cured for 30 minutes at 150°C or 15 minutes at 165°C. Typical cured properties include 120°C Tg by TMA, 23 ppm/°C α1 CTE, 0.5 W/m·K thermal conductivity, and 1 × 1015 ohm-cm volume resistivity.
Key features
- High-purity, semiconductor-grade epoxy underfill for flip-chip encapsulation
- 6,000 cP viscosity for capillary flow beneath small die and devices with stand-off heights above 25 µm
- Self-filleting flow behaviour designed to limit bulky material accumulation on top of the device
- Corner-dot dispense process with 100°C substrate preheat
- Fast cure in 30 minutes at 150°C or 15 minutes at 165°C
- Engineered for compatibility with 260°C peak lead-free reflow exposure
- Low extractable chloride, sodium, and potassium levels
Applications
- Flip-chip underfill encapsulation
- Small-die and fine-gap assemblies with stand-off heights above 25 µm
- Assemblies requiring subsequent over-moulding and lead-free reflow compatibility
TDS, SDS & Technical Documents
Technical Specifications
General Properties
Physical Properties
Electrical Properties
Thermal Properties
Additional Information
CoolTherm® ME-525 Underfill Encapsulant
A one-part, semiconductor-grade epoxy underfill developed for flip-chip device encapsulation. ME-525 is formulated for capillary flow beneath small die and devices with stand-off heights above 25 µm, while providing a self-filleting edge profile, high cured Tg, controlled thermal expansion, and strength for subsequent over-moulding processes.
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Low-viscosity frozen underfill properties
ME-525 is supplied as a frozen black liquid. Its viscosity value is tied to the published CP40 test at 5 rpm and 25°C.
| Property | Typical value | Context |
|---|---|---|
| Appearance | Black, low-viscosity liquid | One-part semiconductor underfill. |
| Viscosity at 25°C | 6,000 cP | CP40, 5 rpm. |
| Specific gravity | 1.70 | Typical as-supplied value. |
| Gel time at 150°C | 5 minutes | Gel time is not equivalent to the full cure schedule. |
| Working life at 25°C | 36 hours | Ambient working-life value after conditioning. |
Thaw upright, preheat the substrate, purge, dispense a corner dot, and cure
Warm the frozen syringe naturally to room temperature, ideally 20–25°C, while keeping it vertical with the dispense tip facing downward. Before application, preheat the substrate to 100°C to reduce underfill time.
- Do not use ovens, hot plates, hot-air guns, warm water, or other artificial heat sources to accelerate thawing.
- Mount the syringe on thoroughly cleaned dispensing equipment.
- Purge until an unbroken flow of underfill is extruded.
- Dispense as a corner-dot extrusion and allow capillary flow beneath the device.
- Cure for 30 minutes at 150°C or 15 minutes at 165°C.
- Remove uncured material with acetone or isopropanol, subject to substrate and process compatibility.
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Allow the frozen syringe to reach 20–25°C naturally with the tip facing down.
Bring the substrate to 100°C before underfill application.
Establish unbroken flow and apply a controlled corner-dot extrusion.
Allow capillary fill and cure for 30 minutes at 150°C or 15 minutes at 165°C.
Frozen storage and handling
Shelf life is six months from the date of manufacture when stored at -40°C in the original unopened container. Keep syringes vertical with the dispense tip facing downward; do not store them horizontally. Transfer received material promptly to -40°C storage, use first-in/first-out inventory control, wear insulated gloves when handling frozen containers and review the current regional SDS and product label before use.
Thermal, mechanical, electrical and ionic properties
The following values are typical cured-material or joint-test results. They do not independently establish package-level warpage, solder-joint stress, voiding or long-term reliability for every die, board, gap and process.
| Property | Typical value | Context |
|---|---|---|
| Glass transition temperature | 120°C | By TMA. |
| Coefficient of linear thermal expansion | 23 ppm/°C α1; 85 ppm/°C α2 | Below- and above-Tg regions must remain distinct. |
| Thermal conductivity | 0.5 W/m·K | Bulk cured-material property. |
| Volume resistivity at 25°C | 1 × 1015 ohm-cm | Bulk electrical property; not an assembly working-voltage rating. |
| Die-shear strength | 9,400 psi | Tested joint result; specimen details are not stated in DS3737. |
| Storage modulus | 4,000 MPa | Cured-material modulus under the supplier test condition. |
| Moisture absorption | <0.5% | Duration and conditioning details are not stated in DS3737. |
| Extractable chloride | <10 ppm | Extractable ionic-contaminant result. |
| Extractable sodium | <5 ppm | Extractable ionic-contaminant result. |
| Extractable potassium | <1 ppm | Extractable ionic-contaminant result. |
Flip-chip underfill for small die and subsequent package processing
The documented role is capillary underfill encapsulation of flip-chip devices. ME-525 is described for small die and stand-off heights above 25 µm, with adhesion to laminate, ceramic, solder mask and metal surfaces. Package-level validation must address the actual gap, die dimensions, dispense volume, flow path, fillet geometry, surface condition, cure and subsequent reflow or over-moulding process.
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Microelectronic Materials Catalogue — PC3003
The catalogue identifies ME-525 as a high-purity one-component underfill with 6,000 cP viscosity, 30-minute cure at 150°C or 15-minute cure at 165°C, 0.5 W/m·K thermal conductivity, 1 × 1015 ohm-cm volume resistivity and 120°C Tg.
Open the Microelectronic Materials CatalogueElectronic Materials Handling — -40°C Storage
UI3022 provides frozen-storage orientation, insulated-glove guidance, FIFO handling, ambient thawing, typical thaw times, condensation removal and syringe-tip purging instructions.
Open the -40°C handling instructionsValidate ME-525 for your flip-chip underfill process
Krayden can help review package gap, stand-off height, substrate and die preheat, dispense position and volume, capillary-flow time, fillet geometry, frozen handling, cure, reflow, over-moulding, ionic requirements and package-level reliability for CoolTherm® ME-525.
