Microfabrication and micromachining are terms that describe the technologies and processes used in making microscopic structures or devices. These structures can range in size from the width of a human hair down to smaller than a single human cell. The ability to build devices this small has spurred technological advancements in computers, consumer electronics, green energy technology and many other fields. Microfabrication techniques vary widely depending on the device being built.
In the field of microfabrication, sizes are measured in micrometers. A micrometer, frequently known as a micron, is one-thousandth of a millimeter. There are 25,400 microns in one inch. Nanotechnology is a similar field, but it deals with even smaller components.
The use of microfabricated parts was pioneered by the semiconductor industry. The inventions of the transistor and integrated circuit in the 1940s and 1950s gave rise to a miniaturization trend in electronics. As microfabrication techniques improved, smaller and more complex integrated circuits were built, allowing powerful microchips to be built.
An increasing number of industries rely on microfabrication. Tiny machines known as micro-electro-mechanical systems can be found in many devices, including smart phones and car airbag sensors. Fuel cells and solar panels also use microfabricated parts. Microfabrication techniques and technologies have been used in research applications in fields from microbiology to particle physics.
The techniques used in a microfabrication process depend on the industry and desired result. Most techniques are top-down approaches, meaning that they start with a larger component, such as a silicon wafer, and remove from it until the final structure is created. Examples of top-down techniques used at the microscopic level include cutting, polishing and etching.
Bottom-up manufacturing in this field is a largely experimental field. In the bottom-up approach, smaller items such as atoms or molecules are used to create a larger system or device. Bottom-up techniques are used in applications intended to mimic biological structures or functions.
Many of the techniques used in microfabrication are borrowed from other disciplines. The fields of photography, optics and physics have contributed to microtechnology. Some traditional manufacturing techniques, such as injection molding, have been miniaturized and used in microfabrication.
Regardless of the technique used, fabrication on a microscopic level presents unique challenges. The small size means that a single piece of dust can render a device useless. Microfabrication labs are rooms designed to control airborne particles such as dust and microbes. Workers must wear protective clothing within these rooms in order to prevent contamination of the microscopic parts being created.