Quad-flat No-leads Package
Flat no-leads packages such as QFN (quad-flat no-leads) and DFN (dual-flat no-leads) physically and electrically connect integrated circuits to printed circuit boards. Flat no-leads, also known as MicroLeadFrame and SON (small-outline no leads), is a surface-mount technology, one of several package technologies that connect ICs to the surfaces of PCBs without through-holes. Flat no-lead is a near chip scale package plastic encapsulated package made with a planar copper lead frame substrate. Perimeter lands on the package bottom provide electrical connections to the PCB. Flat no-lead packages include an exposed thermal pad to improve heat transfer out of the IC (into the PCB). Heat transfer can be further facilitated by metal vias in the thermal pad. The QFN package is similar to the quad-flat package, and a ball grid array.
Read more about Quad-flat No-leads Package: Flat No Lead Cross Section, Different Types of QFNs, Advantages, Disadvantages, Comparison To Other Packages, Variants