Use of Water in Semiconductor Industry

PURIFICATION AND USE OF WATER IN

SEMICONDUCTOR INDUSTRY

Jithin Hemanath

Introduction:

Water is the one of the most important compounds for human beings. It has uses in

agricultural, manufacturing and service industry. Out of the total water present on the

earth, 97.5% constitutes salt water, and only the remaining 2.5% is fresh water. Out of the

fresh water reserve on earth, 68.8 per cent is present in the form of glaciers and permanent

snow cover, 30 per cent as fresh ground water, and only 0.3 per cent is present in the form

of lakes and rivers and 0.9 per cent as soil moisture.

Fig 1. Distribution of water across various sources

Since fresh water is such a scarce source, it has to be used at a regulated pace. Industrial

consumption of water should take into consideration the water requirements at all levels of

activities. Some of the most water intensive industries are as follows:

1.

2.

3.

4.

5.

6.

Automobile

Food and beverage

Biotech/Pharmaceutical

Chemical

High-technology/Electronics

Metal Mining and refining

The Semiconductor industry:

Semiconductors are considered to be the building blocks of modern electronic industry. It is

called a ‘semiconductor’ due to its conductivity lying between those of insulators and of

conductors. Its biggest application has been in the manufacture of microchips which are

found in almost every electronic device these days, ranging from mobile phones to

microwave ovens.

The Semiconductor industry is considered to be one of the most water intensive industries

around. It is estimated that approximately 2200 gallons of water in total, of which 1500

gallons is ultra-pure water (UPW) is required for creating an integrated circuit on a 300 mm

wafer. A typical semiconductor manufacturing plant (also called a ‘fab’) consumes between

2 to 4 million gallons of UPW every day, which is approximately equivalent to the water use

of a city with a population of 40 to 50 thousand.

UPW (Ultra-Pure...