How do the integrated circuits work?

An integrated circuit is actually a number of transistors and resistors all formed on the same piece of silicon. These are connected with a layer of aluminium which is chemically formed onto the silicon. Resistors are formed by making the aluminium extremely thin. Capacitors are actually transistor junctions. There is no board involved the whole thing is formed by chemically doping areas of the silicon then adding layers of gl and aluminium. The size of the circuit is dictated by the number of connections it has. Modern Ultra Large Scale Integration chips use multiple layers of aluminium or even copper.