AuRoFUSE™ Preform Technology

■Features

1. ① Can produce Au bumps of various sizes and shapes
   (minimum formable size: 5 µm size, 5 µm gap)
2. ② Has excellent compression deformability as it is a bonding material with porous structure
3. ③ High-density mounting is possible due to minimal deformation in the horizontal direction during compression
4. ④ Oxidation and migration are unlikely as the main component is Au
5. ⑤ Bonding is possible at comparatively low temperatures (from 200℃) and air atmosphere

■Expected applications

Die-bonding materials for optical semiconductors (LED and LD), power semiconductors, ICs

■Manufacturing of AuRoFUSE™ Preforms

1. ① Au/Pt/Ti metallization of the bonding substrate to form the base layer
2. ② Photoresist applied to the bonding substrate after metallization
3. ③ Exposure/development by holding the photomask, corresponding to the preform shape, over the bonding substrate to form a resist frame
4. ④ Flowing of AuRoFUSE™ into the formed resist frame
5. ⑤ Vacuum drying at room temperature, followed by scraping off excess gold particles with a squeegee
6. ⑥ Temporary sintering through heating, followed by separation and removal of the resist frame

■Comparison of AuRoFUSE™ Preforms with other materials

(〇) AuRoFUSE™ Preforms

• The paste is dried prior to bonding to eliminate fluidity, which minimizes spread and allows high-density mounting
• The porous structure of the paste makes it easily formable, which allows bonding even when there is a difference in height between electrodes or differences in warpage or thickness of the substrate

(△) Solder materials

• As the bump pitch becomes finer, the solder material tends to spread outward when melted, which may lead to short-circuiting due to contact between electrodes

(△) Electroless plating

• While this method enables fine-pitch bonding, the relatively high pressure required during the process may cause chip damage

AuRoFUSE™ preforms do not spread outward and are softer than plating bumps

■Example of bonding: Flip-chip bonding

• 
• Recommended condition
  

  Pretreatment:	UV ozonation, etc.
  Thermo-Compression:	200℃, 20MPa, 10sec.
  Post-Bake:	200℃, 60min.

■Characteristic table