[Peace&Chips] Not a Speck of Dust Allowed... Why Semiconductor Factories Insist on 'Purity'

Complete Prevention of External Contamination in Semiconductor Processes
From Cleanroom to Ultra-Pure Water Eliminating Impurities

Japanese Kioxia's Market Share and Sales Decline Due to Contamination Incidents
Clean Manufacturing Enhancing Semiconductor Quality Is Key to Business Competitiveness

Editor's NoteSemiconductors, often called the rice of modern industry. Although it's a term we hear every day, it's hard to explain when asked. Peace & Chips will make the complex concepts and overall flow of the semiconductor industry easy to digest for you. Just place your spoon on it.

[Asia Economy Reporter Kim Pyeonghwa] What image comes to mind when you think of a semiconductor factory? Most people probably picture employees wearing full-body cleanroom suits working along production lines.

The cleanroom suits function to prevent various contaminants and dust generated from the body from escaping into the environment. They also block static electricity that may occur during the work process. Semiconductor factories are especially sensitive to external contamination like this.

An SK Hynix employee wearing an orange dustproof suit is holding a wafer. / Photo by SK Hynix

In semiconductor factories, semiconductors are mainly produced through numerous processes based on eight major steps on silicon (Si) round substrates called wafers. A protective and insulating oxide layer is formed on the wafer, and circuit patterns are drawn at the nanometer (nm; 1 nm is one-billionth of a meter) scale. Then, a thin film is applied, electrical wiring is created, and defective products are filtered out.

Although explained simply, it reportedly takes several months for a single semiconductor to be completed. Since any problem in any process can cause issues, perfect control of contaminants is essential.

Multiple semiconductor chips manufactured on a single wafer / Photo by SK Hynix

To achieve this, semiconductor factories operate their internal facilities as clean rooms. You can understand this as a dust-free, pristine space. A key feature is that the air pressure inside is raised to prevent contaminated outside air from entering, causing air to flow outward.

The floor is densely covered with countless small holes that are difficult to count. These allow air to flow from top to bottom, acting as an air purifier by filtering out unnecessary particles. Even a single piece of organic matter such as dust floating in the air or skin flakes can cause defects, so they are blocked at the source.

Samsung Electronics Pyeongtaek Campus cleanroom. Employees wearing white dustproof suits and a perforated floor can be seen. / Photo by Samsung Electronics

Water, as much as air, is also strictly managed. Since water is mainly used in key processes such as etching wafers, semiconductor factories reportedly use hundreds of thousands of tons of water daily. Ultrapure water, which has impurities such as electrolytes, microorganisms, and bacteria removed, is primarily used.

As semiconductor production gradually increases, securing ultrapure water is directly linked to semiconductor quality. Recently, both the private sector and government have been actively working on domestic production. This is because relying on imports from Japan is seen as a significant potential risk.

An image illustrating the process of cleaning by spraying ultrapure water while rapidly rotating the wafer / Source: Screenshot from Samsung Electronics Semiconductor YouTube channel

How big would the business impact be if contamination issues occur in a semiconductor factory? Looking at a case from a semiconductor factory jointly operated by Western Digital in the U.S. and Kioxia in Japan provides an answer.

In February, two NAND flash factories in Japan halted production due to impurities mixed in materials used for NAND production. As a result, Kioxia's sales dropped by 4.5% and 16.3% in the first and second quarters of this year compared to the previous quarters, respectively. In the second quarter, their global market share ranking also fell from second to third. This is why operating a clean semiconductor factory is directly linked to business competitiveness.