Posts made in September 2020

Gettering in the Wafer Manufacturing Process

Silicon Wafer Manufacturing

A silicon wafer manufacturer might mention that they incorporate gettering into their processes. What is gettering? It’s a step that removes impurities from a silicon wafer. Typically, this step occurs during the crystal growth process or as a facilitator for VLSI manufacturing. Gettering involves several steps. This article will briefly cover why gettering is important.


The Importance of Gettering

As you can imagine, silicon wafers are highly sensitive components that require care and attention to detail before they are used for electronic device manufacturing. Extrinsic gettering is employed to create a form of stress on the silicon wafer, which brings out the impurities of the material that are later removed.


The presence of impurities is among the leading cause of silicon wafer failure. They can adversely affect conduction, compromising printed circuits in the process. An impurity can also become a hindrance to the wafer polishing process. Inconsistencies in a wafer’s composition can create a defect, ultimately leading to the failure of an electronic device or semiconductor.


Gettering also has its advantages, as it removes any excess gases that might be present in the wafer material. Even the minutest amounts of gases can cause unstable conduction. Therefore, the gettering process is critical in removing any factors that might damage the wafer.


An impure wafer can mean the difference between success and failure. When consulting with your silicon wafer manufacturer, it is crucial to ensure that they include gettering as part of their services.

How to Clean Silicon Wafers

Silicon WafersSilicon wafers form the foundation of electronics manufacturing. Almost every electronic device that you use today uses them. As such, it is helpful to learn about silicon wafer polishing and the cleaning process.


Silicon wafers are very sensitive pieces–they can be contaminated simply by being exposed to air. As such, cleaning the wafers is an indispensable step in the manufacturing process. Thanks to standardization, there is an industry-recognized, three-step process for cleaning. We will summarize it here.


The Cleaning Process

The first step is solvent cleaning. The wafers are dipped in acetone to eliminate oils and contaminants. Then, the wafers move to a container with methanol. The first step involves two liquids because the solvent (acetone) can leave a residue that might contaminate the wafer. Methanol removes leftover residue.


After getting rinsed with DI water and blow-dried with nitrogen, the wafer undergoes RCA-1 cleaning. This step oxidizes the wafer. The RCA-1 solution is a mixture of ammonium hydroxide and DI water.


Finally, the wafers are placed in a hydrofluoric acid dip. The acid dip removes the oxidized layer formed form the second step. Hydrofluoric acid is highly volatile, so the step requires protective equipment.


This standardized cleaning procedure purges the wafer of contaminants, ensuring they are ready to proceed with the manufacturing process. Many wafer manufacturing firms offer this service as part of their silicon wafer polishing solutions.