Flux-free solder connections are essential in power module production. Therefore, instead of solder paste so-called solder preforms are used. The preforms are fed to the assembler on reels and cut to the required length directly on the machine.
The assembly head picks them from the feeder with special nozzles, which guarantee an absolute evenness of the preform, and places them correctly and precisely onto the substrate.
Depending on the cycle time requirements, the assembling of the preforms and the power semiconductor as well as the dispensing of a bonding agent can be realized on the same machine.
The preform feeder can easily be changed without opening the machine door. On an external setup station, new solder tapes can be equipped and prepared for their next use.
Flyer - Die Bonder
The assembly of power semiconductors (IGBT, diodes) on the substrates is more or less a standard process. Our solution offers the advantage that the power semiconductor can be directly assembled from the wafer onto the substrates in a large-scale oven carrier. Thus, the repositioning of the substrates from a small workpiece carrier into the oven carrier can be skipped.
Moreover, the power semiconductors have a large edge length and are quite thin, which requires an ejection from wafer with a needle bed. Thereby no cracks in the chip occur. Even inaccurately mounted wafers can automatically be oriented in their rotational position and correctly aligned to the portal, so that the multiple needles do not miss the chip.
If needed, the assembling of the preforms and the power semiconductor as well as the dispensing of a bonding agent, can be realized on the same machine, depending on the cycle time requirements.
The assembled and wired power modules have to be covered by a polyimide insulation layer. Thereby, the surfaces of the power semiconductor as well as the bond wires or specific boundary areas have to be covered very accurately. The fully integrated vision system uses the specific structures on the substrates to align the dispensing system exactly to the target position.
Normally, jetting is used as a common dispensing technique. The Infotech Component Matrix offers a multitude of modules for purging, cleaning and recalibrating dispense systems as well as for process and quality monitoring.
Flyer - KGD Tester
A special form of tests can be found in power modules production. For static and dynamic tests as well as partial discharge tests to verify the isolation, special test devices and special test environments are needed. Along with generators that produce high voltages and currents.
The test objects are moved into a test chamber, flooded with CO2, fed to the test system and connected to the test system over a contact unit. During the test procedure, the handling system can unload a second, already tested module and place it into the required output format.
Flyer - Power Module
The assembled and soldered power electronics module must be connected to the outside world, i.e. to the package and its housings. There are various processes for this. One of them consists of picking up the contact pins provided as bulk goods, turn them in an upright position and press them into the pin housings pre-assembled on the module. The force-displacement diagram is recorded during the process and forwarded to the appropriate server in a suitable form for traceability purposes.