Sintered Gold(Au) Bonding Technology: AuRoFUSE™ Preform
What is "AuRoFUSE™ Preform"?
This is an Au sintering bonding technology for high-density packaging that utilizes AuRoFUSE™, a low-temperature sintering paste for gold-gold bonding developed by TANAKA. It contributes to efficient packaging processes and high reliability of bonding, and has high-performance properties such as electrical resistance of 4.5µΩ·cm and thermal conductivity of 200W/m·K.
Technical Information on AuRoFUSE™ Preforms
Sintered Au bonding technology for high-density mounting using AuRoFUSE™
In this technology, the bonding material is dried prior to bonding to eliminate fluidity, which suppresses creeping and minimizes spreading in the horizontal direction, thereby allowing fine-pitch bonding. So far, bumps of 5 µm have been successfully formed, and this technology is expected to be used as a bonding technology for flip-chip bonding that require high-density mounting.
Features
- ①Can produce Au bumps of various sizes and shapes
(smallest size formable: 5 µm size, 5 µm pitch) - ② Has excellent compression deformability as it is a bonding material with porous structure
- ③ High-density mounting is possible due to minimal deformation in the horizontal direction during compression
- ④ Oxidation and migration are unlikely as the main component is Au
- ⑤ Bonding is possible at comparatively low temperatures (from 200℃) and air atmosphere
③ Shape Deformation rate when bonding pressure is increased
Expected applications
Die-bonding materials for optical semiconductors (LED and LD), power semiconductors, ICs
Manufacturing of AuRoFUSE™ Preforms
- ① Perform metallization using Au/Pt/Ti as a base layer on the substrate to be bonded
- ② Apply photoresist to the substrate for bonding after metallization
- ③ Place a photomask that matches the preform shape over the substrate to be bonded, and perform exposure and development to create a resist frame.
- ④ Flowing of AuRoFUSE™ into the formed resist frame
- ⑤ Vacuum-dry at room temperature, and after drying, scrape off excess Au particles with a squeegee.
- ⑥ Temporary sintering through heating, followed by separation and removal of the resist frame
Comparison of AuRoFUSE™ Preforms and Other Materials
(〇) AuRoFUSE™ Preforms
- Drying the paste before bonding to eliminate fluidity can suppress lateral spreading and enable high-density mounting.
- Being a porous structure, it can be easily deformed, allowing bonding even when there are differences in height between electrodes, warpage of substrates, and differences in thickness.
(△) Soldering materials
- As bump pitch becomes finer, solder materials spread laterally when melted, which can cause a short circuit due to contact between electrodes.
(△) Electroless plating
- Can achieve narrow pitch, but requires relatively high pressure during bonding, which can lead to chip damage
Example of bonding: Flip-chip bonding
| Pretreatment: | UV ozonation, etc. |
| Thermo-Compression: | 200℃, 20MPa, 10sec. |
| Post-Bake: | 200℃, 60min. |
Characteristics
| AuRoFUSE™ preform_200℃, 20MPa, 10sec | |
|---|---|
| Electrical resistivity (µΩ·cm) | 4.5 |
| Thermal conductivity (W/mK) | 200 |
| Young's modulus (GPa) | 57 |
| Shear strength (MPa) | >30 |
| Coefficient of Liner Thermal Expansion (CTE) (ppm/K) | 14 |
| Under Barrier Metal | Au/Pt/Ti, Au/Pd/Ni |
Related Information
Please Inquiry
Please feel free Inquiry with any inquiries regarding products, media, competitive funding, etc.