Leadframes with heat spreaders have been developed for mounting high power LSI devices, such as MPUs and MPEGs. Power dissipation of this package is from 2 to 3 W. However, there is a great need for less expensive leadframes for Heatspreader-enhanced Quad Flat Packs (HQFPs) for general use. Therefore, we modified the structure of the leadframe for the HQFP and improved the manufacturing to achieve very low-cost leadframes. The features of this new leadframe are as follows: (1) Nearly the same cost as a conventional leadframe with-out a heat spreader. (2) From 2 to 3 W thermal dissipation. (3) Easy wire bonding. (4) High reliability through solder reflow. This leadframe achieves high thermal performance and guarantees high reliability at the least cost.