Semiconductor devices can either be discrete devices, (each physical device is a single semiconductor component), or integrated circuits (ICs). An IC may contain anywhere from several up to millions (and above!) of individual components!
The common process for manufacturing semiconductor devices is outlined below.
First we must produce a pure mono-crystalline cylindrical ingot of silicon. Mono-crystalline means that all of the atoms are bonded together by covalent bonds (atomic bonds), so it is effectively one big molecule. (As opposed to materials that contain molecules bonded by molecular bonds. i.e . The molecules themselves are formed by atomic bonds, but the molecules are held together by molecular bonds to form the material). One common process of producing ingots is described below.
The ingot is then sliced into circular silicon wafers. These wafers are then used to manufacture many integrated circuits (or many discrete components) on a single wafer. When the process is complete, a saw is used to cut the wafer into rectangular sections, each containing a single circuit or component.
The process of forming the semiconductor components is described below (images courtesy of ""wicki media commons").
The individual rectangular silicon chips can then be encapsulated in an epoxy material, with wires connected between the IC contacts and the connecting leads on the package.