Chips can be bonded to rough
or warped substrates
Bond strength is not stable due to substrate roughness
- When a chip with a AuSn deposition film is bonded, the surface of the substrate is rough and does not attach properly.
- When a chip with a AuSn deposition film is bonded, the warp of the substrate is large and does not attach properly.
AuSn paste is a solder paste that is a mixture of AuSn powder and flux. In addition to flexibility in the supplying shape, since it contains a flux that accelerates the wetting and spreading of the solder, it can fill into the uneven parts of the substrate and get wet, and good bonding can be obtained.
When a chip with a AuSn deposition film is used, since the surface of the substrate is rough / the substrate is greatly warped, the part where the AuSn layer is not in contact remains unwetted even after reflow.
Even if the substrate has surface roughness and / or warpage, the fill into the parts where the distance between the substrate and the chip are uneven, thus good bonding can be obtained.
This video shows a comparison between the bonding of chips with AuSn deposition film, and AuSn paste. AuSn paste ensures good bonding conditions and bonding strength.
Since it is a paste, it can flexibly handle unevenness on the substrate.
The AuSn paste can also flexibly handle the warpage of substrates that are difficult to bond with AuSn deposition films.
Other solutions for AuSn paste
Hope to flexibly change the thickness and shape of AuSn
The chip is misaligned when bonding
Hope to reduce the cost of the cleaning process
There are problems when using paste in mass production
Other related solutions
This solution utilizes
Mitsubishi Materials' AuSn paste.