SMTA International Conference Proceedings


Minimizing Voiding In QFN Packages Using Solder Preforms

Authors: Seth J. Homer and Ronald C. Lasky, Ph.D., P.E.
Company: Indium Corporation
Date Published: 10/16/2011   Conference: SMTA International


Abstract: According to Prismark Partners, the use of QFNs is growing faster than any package type except for flip-chip CSPs. Prismark projects that by 2013, 32.6 billion QFNs will be assembled worldwide, which represents 15% of all IC packages.

However, QFNs can be a challenge to assemble, especially when it comes to voiding. In most QFN assembly processes, solder paste is used as a means of attachment. This approach can be problematic, as excessive voiding often occurs due to the lack of standoff on the component and the high flux content of the paste. The addition of a solder preform can reduce such voiding by increasing the solder volume of the joint without adding flux volume.

Adding preforms to an assembly process is very easy. Preforms are packaged in tape & reel for easy placement by standard pick and place machines, right next to your components. The focus of this paper will quantify the preform requirements and process adjustments needed to use preforms in a standard SMT process. In addition, experimental data showing void reduction using preforms will also be presented.

Key Words: 

QFN, solder preforms, QFN packages, flux



Members download articles for free:

Not a member yet?

What else do you get when you join SMTA? Read about all of the benefits that go along with membership.

Notice: Sharing of articles is restricted to just your immediate work group. Downloaded papers should not be stored on an external network or shared on the internet.


Back


SMTA Headquarters
6600 City West Parkway, Suite 300
Eden Prairie, MN 55344 USA

Phone +1 952.920.7682
Fax +1 952.926.1819