Fluxless soldering using formic acid
Soldering using formic acid vapor in combination with nitrogen (HCOOH + N2) offers significant advantages in assembly and connection technology for applications in optoelectronics and photonics. In these applications, the requirements for packaging technology regarding voids or external contamination are particularly strict. Formic acid offers a reliable reduction of oxides with complete avoidance of flux.
The use of formic acid also ensures a well-wettable surface and thus creates ideal conditions for demanding soldering processes. The module is used for eutectic soldering and thermocompression bonding, for example with indium. In all bonding processes, nitrogen is enriched with formic acid (HCOOH) using a so-called bubbler. The nitrogen-formic acid vapor mixture is fed into the process chamber in a controlled manner and extracted.