Referring to 
Semiconductor Package
Generally, numerous fine electrical circuits are integrated in a semiconductor chip. However, the semiconductor chip may not serve as a finished semiconductor product in itself, and may be damaged due to external physical or chemical impacts. Therefore, the semiconductor chip itself may not be used, but may be packaged and used in an electronic device, or the like, in a packaged state.
Here, semiconductor packaging is required due to the existence of a difference in a circuit width between the semiconductor chip and a mainboard of the electronic device in terms of electrical connections. In detail, a size of connection pads of the semiconductor chip and an interval between the connection pads of the semiconductor chip are very fine, but a size of component mounting pads of the mainboard used in the electronic device and an interval between the component mounting pads of the mainboard are significantly larger than those of the semiconductor chip.