SMTA International Conference Proceedings

The Effects Of Preforms In Paste On Voiding Under Large Area Surface Mount (BTC) Components

Authors: Ellen Tormey, Jerry Sidone, Westin Bent, Karen Tellefsen, Paul Koep, and Rahul Raut
Company: Cookson Performance Materials; Alpha Division
Date Published: 10/14/2012   Conference: SMTA International

Abstract: Voiding in solder joints for bottom terminated components (BTCs) is often excessive and adversely affects component reliability. Voiding for such components can be reduced to some extent by optimizing the solder paste and process parameters such as reflow profile and atmosphere, however, a new approach was investigated to significantly reduce voiding under BTC’s. Designs of experiments were conducted to investigate the effects of preforms in paste on voiding under BTCs. The effects of variables including component type and size, preform size, preforms with and without flux coating, preform-to-paste ratio, solder paste printed pad design, and reflow profile were studied using lead-free SAC305 paste and preforms. The test board design, assembly parameters and voiding results for leaded and non-leaded components such as Fusion Quads (FQs), QFNs and MLFs is presented.

Key Words: 

bottom terminated components; preforms in paste; voiding; tape and reel packaged preforms

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