Abstract
A large number of Sn whiskers have been found on the Pb-free solder finish on leadframes used in consumer electronic products. Some of the whiskers on eutectic SnCu finishes are long enough to short the neighboring legs of the leadframe. Tin whisker growth is known to be a stress relief phenomenon. We have performed synchrotron radiation X-ray micro-diffraction analysis to measure the local stress level, the orientation of the grains in the finish around a whisker, and the growth direction of whiskers. The compressive stress in the solder finish is quite low, less than 10 MPa; nevertheless, there exists a stress gradient around the root of a whisker. From the orientation map and pole figure, we found that the growth direction of whiskers is [0 0 1] and there exists a preferred orientation of [3 2 1] grains on the solder finish. In one of the whisker analyzed, we found that the normal orientation of the grain just below the whisker is different; it is [2 1 0]. © 2003 Published by Elsevier Ltd on behalf of Acta Materialia Inc.
| Original language | English |
|---|---|
| Pages (from-to) | 6253-6261 |
| Journal | Acta Materialia |
| Volume | 51 |
| Issue number | 20 |
| DOIs | |
| Publication status | Published - 8 Dec 2003 |
| Externally published | Yes |
Bibliographical note
Publication details (e.g. title, author(s), publication statuses and dates) are captured on an “AS IS” and “AS AVAILABLE” basis at the time of record harvesting from the data source. Suggestions for further amendments or supplementary information can be sent to [email protected].Research Keywords
- Grain orientation
- Pb-free solder
- Stress gradient
- Tin whisker
- X-ray micro-diffractions