Why are processors square and not round?

Friends who know something about hardware almost know that shape of processor is a square metal plate, and of course there is also a rectangular version. The top surface is flat and smooth, while bottom surface has metal contacts or pins.

While default shape of CPU is a rectangle, I'm wondering if anyone has wondered why isn't CPU shaped like a circle?

1. The CPU we see is not a real CPU

Before answering this question, I want to popularize science among everyone. A small piece of metal that we can see with our eyes and touch with our hands is not a processor hardware case, but its hardware encapsulation.

The processor case is securely fixed in center of case. It's no coincidence that shape of a processor chip is also rectangular, so first let's talk about why a real processor chip has that shape.

2. Starting from production

Many students may know that CPU chips are made of sand. I don't know if this knowledge is due to Mr. Lay's popular science reputation, who wanted to sell mobile phone chips for price of sand.

Sand is composed of silicon dioxide, from which we extract silicon element to make a thick and long monocrystalline silicon rod, and then cut it into thin round silicon wafers, which we are more familiar with the term Wafers. .

Until now, waffle has been round, hence its name. After a number of complex processes, including ion implantation, electroplating, photolithography, etc., many prototypes of small processors appeared on this plate.

Then split plate, separate CPU chips one by one, and remove unsuitable parts, and rest will be qualified CPU chips.

Place processor chip on PCB, cover it with an aluminum cover and connect it with solder or silicone grease in middle, and we see that processor is ready. (Of course, it's not so easy, it's a long time to talk about it here)

3. Why is it square?

Some students may be confused: is there any necessary connection between manufacturing process of a processor and why it is square? In fact, we know that small CPU cubes are cut from a huge round pie, so to keep costs down, it needs to be cut into as many pieces as possible.

If many round sections are cut out of plane, then remaining gap between circles completely disappears, and when cutting out many small squares, there may be no gap at all, only in plate. There are a few holes left on the edges.

At same time, difficulty of cutting must also be taken into account. Of course, cutting in a straight line is many times easier than cutting in a curve. In this case, process is simplified and CPU performance can also be improved to a certain extent. So the answer to this question is not really difficult. The CPU is square, simply because a square is easier to cut and has a higher utilization rate, which means less waste.

Although cost control is an inevitable result of businesses' pursuit of profit, it is because of this that we can buy one of most advanced human technologies for just a few thousand or a few hundred yuan. can you feel beauty of this wisdom?