Si Wafer | The Process of Etching a Wafer’s Surface


December 24, 2019

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The etching is a method used to get rid of unwanted materials from an Si wafer. It is carried out immediately after the photolithography process. The etching is not selective. Thus, the need to trace the pattern onto the wafer using photoresist. There are two main types of etching, wet etching, and dry etching. In this article, we will discuss to you what you need to know about etching and its process.

What is Etching?

The photoresist leaves a pattern on the Si wafer in the exact pattern of the mask. The hardened pattern is then cleaned using another chemical. This process is called wet etching.

What is Wet Etching?

Wet etching is a process that utilizes chemicals to get rid of unwanted material on a wafer's surface. The process is done in by batch which is good because this makes sits affordable and capable of etching multiple wafers at a time. The wafer is dipped into a pool of highly concentrated acid. Immediately, the exposed areas of the wafer are carved away. The only drawback of using this method is that it doesn't permit smaller complex geometries that are necessary for today's ICs and chips.

What is Dry Etching?

Dry etching is a process that utilizes gas, instead of chemical etchants, to remove unwanted materials on a wafer’s surface. What’s great about dry etching is that it is capable of generating very small critical geometries.

What is Plasma Etching?

Plasma Etching is a process that utilizes gas that is put under an intense electric field to achieve a plasma state of matter. There are two different types of plasma etching based on the shape of the chamber used.

  • Barrel type chamber- the wafers are placed upright while gas is flowing over them and out it goes through an exhaust pipe.
  • Parallel Plate Reactor- two plates that are utilized to create an electric field to charge the gas, instead of using a coil.

The gases are very reactive in their plasma form, providing very effective etching for the exposed wafer surface. It can also provide good critical geometry. The only drawback is that there’s a possibility of damaging the wafer from the RF radiation.

who offers an si wafer?

Looking for an Si Wafer?

If you’re looking for a high-quality Si wafer at a reasonable price, you can get them at Wafer World. Contact us for inquiries or you can purchase wafers online!

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