Vacuum soldering

We supply a wide range of vacuum soldering systems, covering the full range with our batch and inline systems. Today’s customized vacuum soldering applications extend far beyond the traditional field of electronics. Vacuum soldering applications are finding use in all areas of modern micro-technologies (microelectronics, micromechanics and micro-optics), as well as in the manufacture of mechatronic products (MEMS, OMEMS).

centrotherm’s thermal vacuum soldering systems reach process temperatures of up to 650°C. Thanks to heat transfer in the vacuum through contact or radiant heat, they offer excellent temperature uniformity. The heating rates extend up to 300 K/min and the cooling rates up to 180 K/min. The vacuum or the pressure can be reduced to 10^-5 mbar. The short cycle times enable high throughput and low consumption of materials. The centrotherm Central Machine Control (CMC), with its self-explanatory graphical elements for intuitive operation, has EN 13849 certification. Constant data logging ensures total process traceability, while unrestricted remote operation is also available.

Voidless

Pressure is dropped to 1 mbar (optional 10^_-5 mbar) in the liquid phase of the soldering process, whereby the existing voids, which are found in the solder and continue to exist under normal pressure (DIN 1343 1013.25 mbar), can escape externally through the solder. This leaves the surface relatively void-free with less than 2% (optional < 0.5%). This figure stands at up to 20% for other reflow furnaces. The figures below show a solder joint with voids and a voidless solder joint respectively.

Fluxless

One of the main problems with reflow soldering technology is the constant oxide layers found under atmospheric conditions on the solder deposit and the substrate. Process safety in reflow soldering technology therefore also involves oxide removal and the prevention of oxidation on the soldered connection elements. Flux is usually used for this purpose. In centrotherm’s vacuum soldering process, flux can be completely substituted by using nitrogen (N₂), forming gas (N₂/H₂ 95/5), hydrogen (H₂), formic acid (HCOOH) or by RF plasma with process gas. However, the use of flux remains an option with all centrotherm vacuum soldering systems.

Ultraclean

The parts assembled and connected by soldering are not contaminated thanks to the fluxless process. Ultra-cleaning is carried out using a controlled low plasma with the appropriate process gas. This enables wafer-like processing (advanced packaging). The quality of the processes following vacuum soldering, such as wire bonding, is also improved.