When manufacturing Power LEDs, cleaning takes places after the die attach process in order to remove flux residues and to properly prepare the substrate and chip surfaces for subsequent wire bonding.
If flux residues on the substrate and specifically flux spatter from the soldering process on the chip surfaces are not completely removed, they can lead to unfavorable bonding conditions. These often result in heel cracks and even chip defects due to unnecessary high wire bonding power.
A cleaning process using water based cleaning agents or modern solvents that has been specifically developed for Power LEDs provides optimal surface cleanliness for wire bonding and guarantees a higher yield.
Furthermore, the LED quality itself is significantly influenced by the cleaning process. Optimally cleaned LEDs offer not only a higher light conversion, higher luminosity and color fastness but also a longer product life.