The present invention relates to a chip package assembly, and more particularly to a semiconductor chip package assembly with improved heat dissipation performance.
In a conventional method for forming a semiconductor chip package assembly, a chip (or a chip package) is electrically connected to a package substrate and mechanically bonded in a solder joining operation. The chip is aligned with and placed onto a placement site on the package substrate such that the solder balls are aligned with electrical pads or pre-solder on the substrate. The substrate is typically composed of an organic material or laminate. Heat is then applied causing the solder balls to alloy and form electrical connections between the chip and the package substrate.
For chip packages, electrical performance and dissipation control are two major challenges. In the aspect of electrical performance, chip packages have to maintain signal integrity and operating frequency of semiconductor devices. In the aspect of dissipation control, it is required that chip packages efficiently dissipate heat generated by the semiconductor chip.
A heat spreader or lid, typically composed of a high thermal conductivity material, and having substantially the same dimensions as the package substrate is typically attached over the substrate and the chip by a thermally conductive adhesive. The purpose of the heat spreader is to disperse the heat generated during operation to reduce stress in the package.
With the rapid development of semiconductor technology, the number of I/O pads in a chip has dramatically increased, and the power that each chip consumes has also increased. The heat spreader typically mounted on the inactive surface of the flipped chip does not efficiently dissipate the heat from the active surface of the chip (or land side of a chip package). Therefore, there is a need in this industry to provide a chip package assembly with improved heat dissipation performance.