ensure your components are functioning as intendedPower Electronics Cleaning
ZESTRON offers water and solvent based process solutions for cleaning power electronics such as DCBs, IGBTs, discrete components on leadframes, and Power LEDs.
Water & solvent based solutions
These processes ensure that optimal results are achieved when performing shear and power cycling tests and that the substrates are fully cleaned prior to the subsequent bonding and molding processes.
cleaning for optimal bond quality
Power Modules
Cleaning IGBT modules, i.e. DCBs, is an absolute must within the power electronics industry. The substrate surfaces must be prepared for wire bonding after the die attach process. Cleaning is also necessary after the "heat sink soldering" process and before modules are further processed, that is molded, wire bonded and/or connected to the frames. There are two main requirements for the cleaning process:
- Complete removal of contaminants that typically remain on substrate surfaces, and chips. Residues can impair achievable shear values for copper and IGBTs.
- Visually spot-free substrate and chip surfaces such that it is able to activate oxidized surfaces.
Using specifically developed processes with aqueous-based ZESTRON cleaning agents, clean surfaces can be achieved that will significantly increase the wire bond quality. Consequently, shear tests results as well as the qualification through power cycling (long-term reliability) test will be significantly improved. This also increases the product yield.
Using modern water-based cleaning processes provide optimal compatibility with various chip passivation and substrate surfaces. Eliminating the need for subsequent plasma treatments that are typically necessary, unsuitable cleaning agents attack the passivation leading to impairment of chip function.
improved bond quality
Lead Frames
Leadframe-based discrete components, such as MOSFETs, QFNs, SOTs, etc. are soldered onto the base substrate using a die attach process. The typical or standard wire bond connection is partially replaced with clip bonding technology wherein the connection between the die and lead consists of a copper bridge that will also be soldered with a paste.
ZESTRON’s aqueous and solvent based cleaning media, that have been specifically developed for cleaning leadframe-based discrete components, provide excellent cleaning results leading to higher bond quality, and therefore improved pull and shear test results as well as optimal molding adhesion. Cleaning agents attack the passivation leading to impairment of chip function.
surface activation
Power LEDs
When manufacturing Power LEDs, cleaning is required following wire bonding and the die attach process to ensure optimum bond strengths and yields, surface activation as well as provide an improved bond between the die and substrate.
If flux residues and specifically flux spatter from the soldering process on the chip surfaces are not completely removed, it can lead to unfavorable bonding conditions. These often result in heel cracks and even chip defects due to unnecessary high bonding power. Poor bond strengths and low yields are often due to process contamination.
A cleaning process using aqueous-based cleaning agents or modern solvents that has been specifically developed for power LEDs increases wire bond strength and enhances heat transfer in die attach guaranteeing higher yields.
Optimally cleaned LEDs offer not only a higher light conversion, higher luminosity and color fastness but also extends product life.
