In recent years, with a higher integration level of semiconductor devices, the storage capacity, signal processing speed and power of the semiconductor devices are also higher, but the volume thereof gets smaller. As a result, this tendency speeds up the rapid development of the semiconductor integrated circuit. Among them, a lead frame is a skeleton of the semiconductor integrated circuit, and as a chip carrier of an integrated circuit or a discrete device, the lead frame is regarded as a key structural component for realizing an electrical connection between a lead-out terminal of an internal circuit of a chip and an external lead by a golden bonding wire, thereby forming an electrical circuit, and hence the lead frame functions as a bridge connected with the external wires. The lead frame mainly includes a chip pad and a lead, where the chip pad is configured to provide a mechanical support for the chip during a packaging process, and the lead is configured as an electrical pathway for connecting the chip out of the package. It is apparent that the lead frame first functions as a support for the packaged electronic device and prevents resins from surging between the leads and further supports plastics; and second functions to connect the chip to a substrate in order for providing an electrical pathway and a thermal pathway on Printed Circuit Board (PCB) of the chip. When the integrated circuit is operating, heat generation is inevitable, especially for circuits with large power consumption. As a result, it is necessary for the lead frame to have an excellent thermal conductivity in operation, thus preventing the chip from being burnt due to the large heat generation which is not undissipated immediately. The lead frame is mainly used for providing a mechanical support carrier for the chip of the integrated circuit, and further is used as a conductive medium for connecting the integrated circuit with the external circuit and transmitting electrical signals, and along with the packaging material, to emit the heat produced during the operation of the chip.
The heat is dissipated in the existing lead frames by heat sinks. However, excessive leads located on the chip would cause relatively slow heat dissipation. In addition, the combination of the existing lead frame with the heat sinks still has other defects, such as the inaccurate combination, the lower efficiency.
The Chinese utility model patent CN201629305U discloses a radiating and packaging structure of a lead frame, which includes a lead frame and a radiating fin, where through holes are arranged at the periphery of the lead frame; the radiating fin is provided with bumps matched with the through holes; and the lead frame and the radiating fin are being in the stamping and clamping connection with each other by means of the bumps and the through holes. Such a structure employs the stamping and clamping connection manner, but the heat dissipation function is limited.
The Chinese utility model patent CN202394951U discloses a heat radiating fin of a lead frame of an integrated circuit, where a groove is provided at the middle of the bottom surface of a heat radiating fin body; an insert is located in the groove and matched with the groove; and a silver layer is coated on the outer surface of the insert. However, the heat dissipation function of this heat radiating fin is also limited.