As a conventional semiconductor device, a chip scale package (CSP)-type semiconductor device is known. This semiconductor device is manufactured as follows. First, a plurality of semiconductor chips is formed on a semiconductor wafer, and these semiconductor chips are sealed with a resin, or the like. This enables a plurality of semiconductor devices to be integrally formed on the semiconductor wafer. Next, the plurality of semiconductor devices is divided into individual pieces. Accordingly, the CSP-type semiconductor devices are manufactured. The CSP-type semiconductor device manufactured in this way is manufactured at low cost because a plurality of semiconductor devices is integrally packaged in the wafer process.
In this semiconductor device, external connection terminals are provided on a back surface of the device with solder balls, for example. The semiconductor device is flip-chip mounted on a mounting board through the external connection terminals.
Conventionally, this semiconductor device radiates heat generated from the semiconductor device to the mounting board through the external connection terminals. However, in recent years, semiconductor chips capable of high output at a high-frequency band, such as a field effect transistor, using a GaN-based material have been developed. In a CSP-type semiconductor device that incorporates such a high-output semiconductor chip, there is a problem that the quantity of generated heat is increased, and the semiconductor device cannot be sufficiently cooled by a conventional heat radiation method.
To solve the problem, a technique to provide a heat sink on an upper surface of the semiconductor chip can be considered, for example. However, one of advantages of the CSP-type semiconductor device is low cost of device. Therefore, if the heat sink is provided, the cost is increased, and the advantage of the CSP-type semiconductor device is impeded.
Further, the conventional CSP-type semiconductor device has a structure that simply seals the semiconductor chip with a resin, and thus does not have electromagnetic shield. However, with high frequencies of signals used for the incorporated semiconductor chip, providing of the electromagnetic shield has been demanded in order to separate the semiconductor chip from outside.
USPTO Backgrounds
USPTO Backgrounds