Ultra-Fine Printing Solder Paste

Printing solder paste is a kind of solder paste that is printed on the substrate pads through the stencil apertures. Printing solder paste is widely used in the SMT and semiconductor packaging processes. Printing solder paste is the most prevalent kind of solder paste in electronic assembly. Extraordinary printing solder paste requires excellent solder release performance, long stencil life, superior anti-slump performance, and outstanding thixotropic performance.

The specific surface area of the solder alloy is large as ultra-fine solder pastes (T6 and above) have small particle sizes. A large surface area of the solder alloy leads to a great increase of contact area with the air, which makes it easier to be oxidized. With the progress of printing, the solder paste with inappropriate control of oxygen content will be continuously oxidized in the air, resulting in dramatic changes in viscosity and thixotropy, thus reducing the stability and reliability of the process.

One of the keys to controlling the quality of ultra-fine solder paste is to reasonably control the oxygen content of the ultra-fine solder powder in solder paste, thereby ensuring the process stability of the printing solder paste.