How are microprocessors made

Processor manufacture - from sand to microprocessor

Since I've been looking for how CPUs are made myself a few times, I thought I should open a thread in which I explain exactly how a CPU is made.

Step 1: the silicon

As some may know, the chip (DIE) of CPUs is made of silicon. This silicon (please do not confuse it with silicon!) Is mostly contained in sand - especially in quartz sand - in the form of silicon dioxide. (SiO2)

There are 3 different ways of filtering out this silicon (in the laboratory): 1.) By reduction, 2.) By the aluminothermic process and 3.) By element coverage.

Step 2: the ingot

After you have pure silicon, it is melted down and cleaned and processed until it is suitable as "Electronic Grade Silicon". From this cleaned and liquid silicon, a large crystal with a regular structure is obtained by slowly turning it, a so-called "ingot" is created.

Step 3: the wafer

After the ingot has solidified, it is cut into thin silicon wafers. These thin slices are called wafers. The typical diameter is 30 cm. But before the wafer can be used, it is polished for a long time until a flawless surface is present. Only then can it be used for "High-K / Matel Gate" production, with structure widths of 45 nm (32 nm).

Step 4: the photolithography

A liquid is poured onto the wafer: photoresist, as it is also used in analog photography. By rotating the wafer extremely quickly, the photoresist is distributed evenly and very thinly.

After the photoresist has been applied, it is irradiated with UV light. A lens reduces the pattern of the mask, which is why the structures on the wafers are much smaller than those of the mask itself. (The photoresist exposed to the UV light becomes soluble.)

There is also a second exposure; Here, special attention is paid to the smallest component of the CPU: the transistor, it acts as a switch in the processor => control of the current flow in the CPU.

Step 5: etching process

The photoresist dissolved by the UV light is now removed using a solvent. The non-irradiated photoresist now secures the areas that should be preserved. Unprotected areas are etched away with the solvents.

After the etching process, the photoresist is removed and the desired basic silicon shape emerges.

Step 6: the ion implantation

Before this step, photoresist is applied again, irradiated with UV light and cleaned again. However, the photoresist now protects against the implantation of ions. During the ion implantation (part of the "doping") itself, the wafer is irradiated with ions. They are implanted to optimize electrical conductivity. The ions hit the wafer at speeds of over 300,000 km / h.

After the ion implantation, the photoresist is removed again. The desired silicon shape is now visible, with the "doped" areas now showing some foreign atoms. (NPN layer)

Step 7: the metal application

Now the transistor is almost finished - 3 holes are now etched into the applied insulation layers, these are then filled with copper in order to establish a conductive connection to other transistors.

Electroplating takes place - the wafers are immersed in a copper sulphate solution. The copper ions now migrate from the positive anode to the wafer, which acts as the cathode. The copper ions are deposited on the transistor.

After electroplating, a thin copper layer has formed from which the copper that is no longer required is polished off.

Step 8: metal layers - layers

After there are a lot of transistors on the wafer, they just have to be able to communicate with each other. This is made possible by metal layers which, like wires, create a connection between the transistors. How and where these wires are laid is determined solely by the processor architecture.

Step 9: wafer test / cut

After the layers have been laid, the wafer is now cut into individual chips. After that, the chips have to endure a few tests to see if they are working properly. Only those DIEs that have passed all the tests go on sale. The DIEs that are not fully functional are sorted out.

Step 10: packaging

After the chips have passed the test run, they are sent to packaging. In this step, the DIEs receive their carrier board and headspreader.

Step 11: performance test

After all these steps, there is still a performance rating: The processors are tested for their performance and are assigned according to heat radiation and maximum clock frequency.


These are the most important steps in CPU manufacturing.

I hope for some reviews and also that I was able to help some people.

Mfg Agena

PS: sources were hung on.


  • quellen.txt
Last edited: