Like building a house out of Legos, IC chips create their desired shape by stacking them up on top of each other. However, there are quite a lot of steps to build a house, IC manufacturing is the same, what are the steps to make IC? DiskMFR in this introduction to the IC chip manufacturing process.
▮ Layered chip architecture
Before we begin, we need to know what an IC chip is. IC, full name Integrated Circuit (Integrated Circuit), from its name can be known that it is designed Circuit, in the way of stack combination. In this way, we can reduce the area required to connect the circuit. The following is a 3D diagram of an IC circuit, and you can see that its structure is like the beams and columns of a house, stacked on top of each other, which is why manufacturing IC is compared to building a house.
The 3D profile of an IC chip in the image above, shown in dark blue at the bottom, shows how important the wafer substrate is in the chip. As for the red and khaki part, it is the place to complete the IC production.
First of all, the red part here can be compared to the hall on the first floor of a high-rise building. The hall on the ground floor, which is the gateway to a house, is usually more functional under the control of traffic. Therefore, compared with other floors, construction will be more complex and need more steps. In an IC circuit, this hall is the logic gate layer, it is the most important part of the whole IC, by combining a variety of logic gates together, completes the functional IC chip.
In yellow, it looks like a regular floor. Compared to the first floor, the structure is not too complex, and each floor does not change much when it is built. The purpose of this layer is to connect the red logic gates together. So many layers are needed because there are too many lines to be connected together, and when a single layer cannot accommodate all the lines, several layers have to be added to achieve this goal. In this, different layers of wiring are connected up and down to meet the needs of the wiring.
▮ Layered construction, layer-by-layer architecture
Knowing the construction of IC, the next step is to introduce how to make it. Imagine if you want to paint spray cans to do fine drawings, we need to cut the graphic cover plate and cover the paper. Then spray the paint evenly on the paper. When the paint dries, remove the shutter. Repeat this step over and over again, and you get neat and complex shapes. An IC is made in a similar way, by being stacked on top of each other in a cover-up manner.
|Step 1||Step 2||Step 3||Step 4|
|Metal sputtering||Coating photoresist||Etching technique||Photoresist removal|
When making IC, can be simply divided into the above 4 steps. In practice, the process varies and the materials used vary, but the principle is similar. This process is slightly different from paint painting, where IC manufacturing is coating and then covering, and paint painting is covering and then painting. The processes are described below.
- Metal spattering: Sprinkle the metal material to be used evenly on the wafer to form a thin film.
- Photoresist coating: first put the photoresist material on the wafer, through the light mask (the principle of the light mask will be explained next time), hit the light beam on the part of the light resist material structure and damage. The damaged material is then washed away with chemicals.
- Etching technology: Silicon wafers without photoresist protection are etched by the ion beam.
- Photoresist removal: use the photoresist solution to dissolve the remaining photoresist, so as to complete a process.
Finally, many IC chips are made on a single wafer, and then the finished square IC chips are cut off and sent to a packaging factory for packaging. What is the packaging factory? We’ll have to explain it later.