There are various steps in Manufacturing Semiconductor Chips!

The semiconductor chip is that invention that changed the world. It is the unsung hero of the technology and electronics industries. Semiconductor chip’s primary purpose is to power toys, cars, computers, smartphones, thermostats, etc.

Over the years, semiconductor chips have contributed immensely to many technology breakthroughs such as machine learning, artificial intelligence, etc. And these breakthroughs have entirely changed the way we work and live.

More than one trillion chips were produced in 2020 alone despite the shortage. However, designing and manufacturing semiconductor chips are very challenging. To make a single chip, there are so many processes to follow to make a single chip, and you are only one mistake away from making heavy losses.

This article will help you learn about the six vital steps involved in Manufacturing Semiconductor Chips.

Step 1: Disposition

You need silicon water to perform this step. First, wafers are cut from pure silicon and polished until they are incredibly smooth. Then, thin films of isolating, conducting, or semiconducting materials are unloaded on the wafer depending on the shape. This will print the first layer on the wafer.

This critical process is known as Disposition. The operation patterning the wafer becomes more difficult as the microchip structure shrinks. Boosts in disposition, Lithography, and etch contribute to shrinking and the pursuit of Moore’s theory. This boost includes the innovation and use of new materials that will enable more accuracy when depositing these materials.

Step 2: Photoresist Coating

After the disposition step, the wafer is covered with a photoresist, a light-sensitive coating. There are two types of photoresists which are positive and negative. The chemical composition of the resist and how it reacts with light is how you know the difference between positive and negative photoresists.

For positive photoresists, the part exposed to ultraviolet will change its composition. This will make it more soluble-ready for disposition and etching. While for negative photoresists, the components exposed to ultraviolet light polymerize, which means they become stronger and more complex to dissolve.

The photoresist popularly used in semiconductor chips production is the positive photoresist. This is because it has better resolution capabilities, making it better suited for lithography.

Step 3: Lithography

This is one of the most critical steps in producing semiconductor chips. Lithography determines how small a transistor used for chips will be. This process is done by putting chip wafers in a lithography machine.

The wafer is then exposed to EUV (Extreme ultraviolet) or DUV (Deep ultraviolet) light. For simple chip designs, the wavelength of ultraviolet light is 365nm. 13.5 is used to manufacture some of the most efficient details of a semiconductor chip, which is way smaller than a grain of sand.

The lithography machine has a reticle that holds the blueprint of the pattern to be formed. When light is projected through the reticle, the system optics shrink and focus the design on the photoresist layer.
Immediately the light hits the photoresist; a chemical change occurs, which enables the pattern on the reticle to be duplicated on the photoresist layer. Getting the exact design can be difficult, which is why it is better to deform the blueprint so you can get the particular pattern you need. Doing this can prevent refraction, particle interference, and other defects.

Step 4: Etch

After Lithography, the following process will remove the debased photoresist to show the needed pattern. In this step, the wafer is developed and baked, and part of the photoresist is washed away to reveal a 3D design of open channels.

This process is called Etch. The etch processes must form increasingly conducive features in a precise and consistent manner without affecting the stability and integrity of the chip composition.

Advancement in etches technology means manufacturers can use double, quadruple, and space-based patterning to produce most of the small features of modern chips. There are two types of etching which are wet and dry etchings.

Dry etching uses gases to determine the exposed form of the wafer. In contrast, wet etching washes the wafer with chemical baths. It is essential to control etch because chips consist of numerous layers. And with chips with so many layers being produced every time, etch is becoming increasingly difficult yet essential.

Step 5: Ionization

The wafer is bombarded with positive or negative icons once patterns are etched in the wafer. Doing this will tune the electrical conducting properties of areas of the design.

Raw silicon is not a perfect conductor or insulator; it’s somewhere between. Bombarding the wafer with electrically charged ions will allow the flow of electricity to be correctly controlled, forming transistors. This step is known as Ionization or Ion implantation.

Step 6: Packaging

After producing the chip and removing it from the wafer, it is diced and sliced mostly with a diamond saw into each chip. These chip dies have various sizes; while some wafers contain a few dozen, others contain thousands of chips.

After this, the chip die is put on a substrate, a baseboard for the chip that uses metal foil to control the output and input signal of the chip to other parts of the equipment. A heat spreader is then placed on top of the substrate.

A heat spreader is a flat metal protective container, primarily small, which holds a cooling solution to ensure that the semiconductor chip stays cool during operations.

Final Thoughts

Designing and manufacturing semiconductor chips is no small feat. It involves numerous delicate processes and can take up to three months or more. Other steps include electroplating, measurement, inspection, testing, etc. Also, each semiconductor chip goes through all these steps repeatedly until it is efficient enough to be used.