Low-temperature Sintering Paste for Au-Au Bonding: AuRoFUSE™
Focusing on the low-temperature sintering properties of submicron-sized gold particles
We have developed a halogen-free gold paste that can be used for gold-gold bonding at 200℃. This paste is made solely from submicron-sized gold particles and a solvent, and can provide metal bonding with low electrical resistivity (5.4µΩ･cm) and high thermal conductivity (150W/m･K).
■Features
Spherical submicron Au particles that do not contain polymers, etc.
- Sintering begins at approximately 150℃ without compression
- A porous sintered body is obtained in the case of uncompressed sintering ⇔ Dense Au is obtained by applying compression
- Outgassing from sintered bodies is low because no organic protective agents such as resins or polymers are used
- High-purity Au is obtained after sintering
- 150℃･5min (expanded)
- 200℃･5min
- 300℃･5min
- 400℃･5min
■Properties of porous bonding obtained by “uncompressed bonding”
| Features | Characteristics of bonding | AuRoFUSE™ 230℃ with no pressure |
|---|---|---|
| Low resistance | Electrical resistivity (µΩ･cm,@25℃) |
5.4 |
| High thermal conductivity | Thermal conductivity (W/mK) |
＞150 |
| High temperature resistance | Heat-resistant (℃) | 1064 |
| Flexible | Young’s modulus (Gpa,@25℃) |
9.5 |
| High strength | Shear strength (Mpa,@25℃) |
30 |
| High content | Au content (mass%) | 99.95 |
| Au-Au bonding | Under Barrier Metal | Au/Pt/Ti, Au/TiW |
■How to Use
- A dispenser method and pin transfer method are used to supply the paste to the gold electrode on the circuit board.
- After mounting the device (gold electrode), bonding is possible in 20 minutes without applying pressure by raising the temperature to 200℃(0.5℃/sec.).
- Bonding is possible in air or gas atmosphere and no washing is needed after bonding.
- Additional heating at 200℃ for about one hour is effective for increasing the bonding strength.
| Form of provision | Paste_drawing number_ TR-191T1000 | |
|---|---|---|
| Container types (container materials) |
Syringe By EFD/5 cc syringe (PP)/ Piston (PE)
|
Pot Paste tube container (PP or PE) *The container depends on the amount.
|
■Comparison of Durability from Differences in Bonding Material
LEDs were flip-chip bonded to a metal circuit board using AuRoFUSE™ with gold-tin solder and silver-tin-copper solder. A LED module was created by mounting 12 LED elements connected in series of two rows. Subsequently, a thermal stress test was performed by applying a load of 24V at 350mA and turning the LEDs on and off (load time was 15 minutes). The results demonstrated a high bonding reliability of the LED devices connecting to gold particles.
Results of LED module bonding reliability test
