Minimizing Voiding In QFN Packages Using Solder PreformsAuthors: Seth J. Homer and Ronald C. Lasky, Ph.D., P.E.
Company: Indium Corporation
Date Published: 10/16/2011 Conference: SMTA International
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.
QFN, solder preforms, QFN packages, flux
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