The Semiconductor Wastewater Story, Ultrapure Water Utilization and Wastewater

Hello, I'm Minhee Hwang from the public relations office.

Today, I would like to introduce wastewater treatment in the electrical and electronics industry, which is a core industry in Korea. The electrical and electronics industry, which is mainly related to the semiconductor process, uses ultra-pure water (UPW) for cleaning semiconductors, displays, and nano-research fields among other electronic components.

Ultrapure water is literally the purest water and is closest to the resistivity level (18.25㏁.cm). Even microscopic debris can interfere with semiconductor current flow, and ultrapure water is free of such debris.

Ultrapure water used to be a Japanese monopoly, but now South Korea has ultrapure water technology as well, and the ultrapure water process requires a 24-step process including ultraviolet oxidation and ion exchange.

Semiconductors are manufactured in ultra-clean environments because they need to be ultra-pure, as any impediment to the flow of current from microscopic particles can cause significant losses in the critical functions of electronics.

Ultrapure water used in the process of washing silicon wafers when making semiconductor wafers. And other electrical and electronic wastewater.

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Semiconductor Processes and Cleaning

Silicon is extracted from sand as silicon crystal growth technology, in which silicon is melted to a high temperature into a solution and cooled to a single crystal, which is then made into an ingot.

This ingot is then saw-cut to produce semiconductor wafers, which generates primary wastewater.

Diagram of electrical and electronic production processes and wastewater generation

The production process of electrical and electronic products varies from product to product, but they are all subjected to ‘cleaning’ with ‘ultra-pure' water, and wastewater is generated during this process.

Inclusions by concentration in electrical and electronic wastewater

Separation	pH	Contents
Low-concentration wastewater	Acidic 3-5	Fluoride ion, nitrate, phosphate, silica, organic matter (BOD, COD), ammonium ion, hydrogen peroxide
High Concentration Wastewater		Sulfuric acid, hydrochloric acid, nitric acid, hydrogen peroxide, fluorine, acid ammonium fluoride, silicone powder

What is suspended solids, the primary effluent of electrical and electronic wastewater?

Suspension water from primary processing: This refers to water containing silica from cutting the primary ingot and processing the wafer in the above process. It is highly turbid but contains few soluble chemicals, so it is purified using membrane filtration technology and a large part of it is reused.

Inorganic Electrical and Electronic Wastewater Treatment Process Diagram

Since the wastewater contains hydrofluoric acid and hydrogen peroxide, the enzyme catalase is used to break it down, followed by neutralization/flocculation treatment with calcium chloride and calcium hydroxide.

The flocculation precipitation byproduct is calcium fluoride sludge, which is sold to cement manufacturers, and the treated water is sand filtered and activated carbonized before being reused.

The above facility process is an inorganic process, and in the case of organic system, additional facilities such as flow adjustment tank, aeration tank, sand filtration tower, activated carbon tower, etc. are required to decompose flocculation treatment water into biological treatment activated sludge.

List of domestic pure/ultrapure water facilities

Separation	Business name	Phone number	Homepage
Net Equipment	Kurita Hansu Co.	031-789-1700	View
Pure/ultrapure	WelchronHantech	031-350-8900	View
Ultra-pure water facilities	Environment	053-763-1911	View
Ultra-pure water facilities	JINYUNG ENTITY	031-457-6565	View
Ultra-pure water facilities	(Corea WaterTrol	02-943-9623	View
Ultra-pure water facilities	Thawing Technology	031. 386. 3901	View
Ultra-pure water facilities	AcroWaterTech	070-5129-6501	View
Ultra-pure water facilities	Techwin	043-261-8114	View