05 Feb 2024 Large area sintering (LAS)
Refers to the bonding of substrates, power modules or printed circuit boards to heat sinks. Due to the large surfaces (>10x10mm), this joining process is referred to as large-area sintering.
The process differs from conventional sintering of semiconductors on circuit carriers in a number of process steps. Due to the large surfaces, different squeegee blades and stencils are required for printing. Drying also requires more time and is sometimes carried out with vacuum support. The actual sintering process is similar, except that significantly higher total forces are required at lower sintering pressure. In addition, the sintering temperature for molded modules is well below 250°C in order to prevent delamination of the mold from the substrate. Therefore, the sintering pastes must already have a clear sintering activity at 200°C. This is currently only possible with silver sinter pastes.
In addition, large-area sintering places significantly higher demands on the warping and flatness of the components and their behavior under temperature.