Performance comparison of thermally enhanced plastic (TEP) packages

Plastic packages have long been the mainstay of VLSI packaging due to a combination of important characteristics such as cost, reliability, and mass producibility. However standard plastic packages and higher pin-count standard plastic quad flat pack (PQFP) packages do not readily lend themselves to applications over 1-2 watts. Over the last few years several techniques have been used to enhance the thermal performance of plastic packages. These include the addition of a thin metal sheet referred to as a heat spreader or a thicker piece of metal called a heat slug internal to the package. These thermal enhancers behave differently depending on the external environment and the printed circuit board´s ability to carry heat away from the package. They also have important differences in other aspects such as cost and manufacturability. This paper discusses several different types of thermally enhanced plastic (TEP) packages, their thermal performance under different ambient conditions, relative costs and manufacturability, and the effects on thermal performance depending on the test environment and how the measurements are made. Such an analysis is useful in selecting the right type of thermally enhanced packages for a given application