What is a Clean Room?

When the first electric-digital computer was unveiled in 1946 in the US for use by the army, it was a huge, 30-ton machine. It used over 17,000 vacuum tubes and over 7,200 crystal diodes to consume a whopping 180 KW of energy. ENIAC, which lay sprawling across an entire room, was truly a cyber-mammoth capable of making thousands of calculations a second. The world has come a long way since.
When transistors got invented, they made vacuum tubes obsolete and gave rise to the second generation of computers – the mainframes. Later still, the era of integrated circuits arrived and they along with the transistors ushered in the third generation of computers which we all use today, called the desktops.
Information technology is now obsessed with miniaturisation in its eternal quest to pack more and more processing power in less and less amount of space. Often, digital devices have microscopic components invisible to the naked eye. Microprocessors are a prime example of how the information technology industry progresses in terms of speed and capability.
A microprocessor is nothing but a tiny silicon wafer. On it are placed millions of microscopic transistors. Each of these can remain in an ‘off’ state (absence of electric current) or ‘on’ state (presence of electric current). The former represents one and the latter, zero. Thus, digital calculations are made possible at a breath-taking speed.
Since the components used in many digital devices such as the microprocessors are microscopic, there is one constant worry while manufacturing them – dust. A tiny spec of dust or any other contaminant floating in the air can actually wreck tiny electronic circuits or get wedged between two components and create havoc. In the world of information technology, the biggest problems are created by things that are no even visible to us! The solution to this problem? Set up a “clean room.”
Clean rooms are exactly what their name suggests. They have hardly any dust particles circulating inside. They are made up of enclosed spaces where the air flow and entry of people are strictly regulated. There are layers of powerful air-filtration systems which process the entire air inside the room about ten times a minute as well as filter the outside air coming in.
These filters extract even microscopic particles of dust and other suspended matter such as human hair, pollen, vapours, microbes and skin flakes. The result is that the air in a clean room is up to 10,000 times cleaner than what is found inside a hospital operation theatre! There are absolutely no air-borne particles that may create problems with sensitive electronic circuits.
Cleaning the air inside a clean room is one thing. Maintaining it at the same level is quite another. That is why special precautions are taken with respect to the people working inside a clean room. They have to wear a bunny suite so that they do not shed skin flakes or hair that may accidentally come into circulation.
The suit is made of lint-free fabric and is static-free, ensuring that it does not add its own contaminants. Everyone entering or exiting a clean room has to go through an air lock and take an air shower. Another trick played to keep clean rooms clean is by keeping their air pressure positive. With this, whenever there is a leak, the air from the room travels outward while the polluted outside air is prevented from coming in.
The most popular classification of clean rooms divides them into various classes, from Class 1,000 to Class 1. The number signifies the number of dust particles in a cubic foot of air. For example, a Class 1,000 clean room will have 1,000 suspended particles in a cubic foot of air, while for a Class 100 clean room, this figure will only be 100. Class 1 clean rooms are obviously the cleanest and most sophisticated.
Clean rooms play a very important role in data recovery. There are many digital storage devices that are very sensitive to dust particles. Hard disks are one of them. These hold all the user data and software programmes. A disk may malfunction due to a variety of reasons. For example, its read and write head may come crashing down on the platters spinning at an incredible speed and just get stuck there. The spindle motor may stop working and consequently the platters may come to a grinding halt. The inner circuitry of the disk such as the controller card may get burnt.
In these cases, to diagnose the problem and carry out repairs or extract the data from the platters, one has to open the hard disk. This can only be done in a clean room because the disk is extremely sensitive to dust.
The read and write head hovers just a sub-micron level above the platters. Even a tiny spec of dust can get wedged between them and cause the disk to crash or the data-recording surface to be scratched. Without a clean ream, it is not possible to carry out any repairs of the hard disk or extract lost data residing on the platter surface.