If you have ever wondered exactly how a motherboard is made, PC Stats has a good article that will show you how.
Finally the motherboards undergo an ‘in-circuit test’ which involves testing each motherboard’s circuit paths, electrical characteristics and the chips that have just been added by applying electrical current to certain specific test points on the board. Each motherboard is placed on a special rack and a testing board is lowered onto it, making contact with the motherboard at specific points. Current is applied, and the results are analyzed by the technician running the station. The whole process takes less than a minute.