Bottom terminated components (BTC) are leadless components where terminations are protectively plated on the underside of the package. They are all slightly different and have different names, such as QFN (quad flat no lead), DFN (dual flat no lead), LGA (land grid array) and MLF (micro lead-frame. BTC assembly has increased rapidly in recent years. This type of package is attractive due to its low cost and good performance like improved signal speeds and enhanced thermal performance.
However, bottom terminated components do not have any leads to absorb the stress and strain on the solder joints. It relies on the correct amount of solder deposited during the assembly process for having a good solder joint quality and reliable reliability. Voiding is typically seen on the BTC solder joint, especially on the thermal pad of the component (...) This paper will present some data to address these concerns.
SMTA - Surface Mount Technology Association is a non-profit international association of companies and individuals (totalling 4,000) involved in all aspects of advanced electronics assembly, surface mount and related technologies.
IPC - Association Connecting Electronics Industries is a US-based trade association dedicated to the competitive excellence and financial success of its nearly 2,600 member companies which represent all facets of the electronic interconnection industry, including design, printed wiring board manufacturing and electronics assembly.