Why Are Silicon Wafers Round?

The image of silicon chips should be familiar to everyone who knows the slightest amount about computer chips. The classic square shape is practically the emblem of computer technology. After all, the silicon chip is the fundamental basic core of computers. It’s present in the tiniest bit of technology. Before a chip is born, however, it starts as a wafer–and those are round.

What Are Round Wafers? 

Round wafers are flat, disc-shaped slices of semiconductor material, typically made from silicon, that are used in the manufacture of electronic devices such as microprocessors, memory chips, and sensors.

Have you ever wondered why silicon wafers used in chip production are round instead of squared or rectangular? Wouldn't there be waste at the edges since the die pieces that are being cut out of the wafer are square?

The Shapes

If the fundamental question with silicon is, Why are chips square and wafers round? then it’s important to understand how silicon wafers are formed. They are made from melted sand, which has a high percentage of silicon in the form of silicon dioxide. The sand is melted in a large vat, and a seed crystal is dropped in. Crystal growth begins around the seed, and the seed is rotated as the growth continues, gradually forming a solid, round ingot.

The circular, cylindrical shape of the wafers is a by-product of the process with which they are grown, called "The Czochralski Growth Method." This method grows silicon crystal by solidifying a crystal-liquid into a solid.

But why are chips square? There are several reasons. First, it’s much easier to cut square chips out using a quick process rather than the complex process of cutting round chips out. Square chips are also more convenient for wire operation. Furthermore, it’s impossible to escape waste with circular chips. In fact, you can more efficiently cut chips from a round wafer than a square one. More integrated circuits can fit on a round wafer than any other shape in fact.

What We Offer

Silyb Wafer Services is proud to offer short-loop patterned wafers that are designed for testing. Central to this is chemical mechanical planarization (CMP), which flattens a surface during the manufacturing of integrated circuits. We’re proud to create some of the finest test wafers in the world though we do not sell prime or silicone wafers. Visit our website to see how we can benefit you. 

Published June 22, 2023.