Computer chips are composed of silicon - the second most common element in the Earth's crust - combined with various metals, which act as wiring and help control electrical charges. Chips go through many steps to get assembled, but they all begin with a super-pure form of silicon called "single-crystal silicon" that allows electricity to pass quickly without losing too much energy.

First, the silicon is grown. This starts with a seed crystal of silicon and grows into a large cylinder of single correct silicon:

This cylinder of silicon will go through many steps to become a computer chip with billions of components etched on it.

There are two methods used to cut the chips from this large cylinder known as Czochralski and float-zone:
Czochralski process: This is a method in which a silicon seed crystal is dipped into molten silicon, then slowly withdrawn from it, creating a single crystal of silicon. You can see an animation of how this works here. The floating zone process uses the same philosophy but instead of dipping the cylinder into molten silicon to extract silicon it heats both ends, melts the middle portion which becomes more fluid due to heating while the end portions are kept solid. Then by rotating one solid portion relative to the other it creates long cylindrical crystals known as boules (singular "boule"):

The next step in fabrication is wafering where ingots are cut up into bars or wafers, about 200 µm in thickness:
Then they are ground down to 50 µm so the surface is flat all the way through. Then metal conductors are added with an alloy chemical process known as 'diffusion':

And this makes wiring connections on the chip. After that comes photolithography when structures are produced via light exposure (similar to how printed circuit boards like TVs and computer monitors work). This involves using masks (left) and etching chemicals (right):

Semiconductor fabrication is a complex process that takes place inside hermetically sealed chambers or "fabs", where the air has been replaced by inert gases like argon, carbon dioxide, nitrogen. Immersion tools like high-purity water baths are used to clean the surfaces. A small chemical plant is required just for cleaning wafers before further processing. After chips are fabricated they go through a doping process where impurities are added via diffusion.