A THERMAL COOLING SYSTEM DESIGN MOUNTING ON THE BOTTOM OF PC BOARD FOR A SLUG-DOWN IC OR ELECTRONIC DEVICE
Publication Date: 2003-Jun-02
The IP.com Prior Art Database
The present thermal cooling system design can significantly reduce the temperature for a slug-down IC or electronic device. The cooling system is mounted on the bottom of PC board. It includes: thermal via on PC board; a heat sink; a cover or surface exposure to air; a thermal conductive material between PC board and the heat sink, between the heat sink and the cover. It is an efficient combination design that utilizes thermal conduction, convection and radiation. The thermal cooling system design for a cable modem consists of a pattern of thermal via, a Cu heat sink, a cover which has enough surface area exposed to air and a thermal conductive material. The thermal via pattern design is a pure conductive path to transfer heat from the solder joint at the top of the board though the PC board to the heat sink at the bottom the board. Since the PC board is a lower conductive material compared with the copper via, most of the heat will follow the via and be transferred to the bottom surface of the board. The thermal via is the minimum practical drilled hole diameter at minimum practical space between holes – plated with minimum of 30 microns Copper. The wave solder mask openings were selected to prevent bridging during HASL and wave. This thermal via pattern design gives the minimum heat conductive distance and less bumped solder layer to reduce the air gap. The thinner the better, the more contact surface the better for the system cooling.