Prevention of Tin Whisker Growing

Tin whisker growing is a phenomenon related mainly to pure bright tin (Sn) terminal finishes. The whiskers may cause shorts between electrical terminals, therefore actions to prevent whisker growing have to be undertaken. A description of tin whisker theory and mitigation practices can be found in the Jedec standard JP002. The here shown measures are based on that standard. Special tests are however not conducted.

The fact that Diotec uses measures to prevent tin whisker growing does not mean that these parts are designed nor produced for aerospace or similar applications, where tin whiskers can be of high risk. Please refer to our disclaimer.

Matte Sn plating with annealing

At this process, matte Sn is applied, without usage of a brightener. After plating, there is an annealing at 150°C for at least 1h. This measures prevent tin whisker growing even at a pure Sn plating. Therefore it is an accepted method for tin whisker prevention.

Usage of hot dipped SnAgCu alloys

Most Diotec parts are using SnAgCu alloy for terminal finish, which is applied in a hot dip tinning process. After plating, there is an annealing at 150°C for at least 1h. A nickel (Ni) underplating provides additional protection against tin whisker growing. For this reason, SnAgCu alloys with above treatment are preferred terminal finishes for prevention of tin whisker growing at Diotec.