You know, the terminals of the integrated circuit, which is basically decided by its fabrication process.

Exactly speaking, due to the intergrated circuit adopts the semiconductor fabrication process, that’s to say, in a monocrystalline silicon wafer, there are a great number of transitors, resistors, capacitor, etc. According to the multilayer or tunnel routing method, those components will be combined into the whole circuit.

That’s why you observe the transistors and integrated circuit have so many terminals.

PS: Transistor includes diode and triode.