Introduction to Cleanroom Technologies & safety Protocols “The success of the manufacture of micro/nanodevices depends as much on the attention to particles control, cleaning and gettering as it does on the design features of a particular product” •

Introduction to Cleanroom Technologies & safety Protocols “The success of the manufacture of micro/nanodevices depends as much on the attention to particles control, cleaning and gettering as it does on the design features of a particular product” • Cleanroom definition and applications • Cleanroom classifications • Micro-contamination • Controlled Environment concepts • Cleanroom practice and protocols • Safety issues Outline Definition of a cleanroom Dictionary (Collins) definition: clean room (kliːn rʊm ) noun (industry) an environment, typically used in manufacturing or scientific research, in which environmental contaminants are kept to an absolute minimum A cleanroom is a room that is clean. A cleanroom now has a special meaning and it is defined in the International Organization for Standardization (ISO) standard 14644-1 as: A room in which the concentration of airborne particles is controlled, and which is constructed and used in a manner to minimize the introduction, generation, and retention of particles inside the room and in which other relevant parameters, e.g. temperature, humidity, and pressure, are controlled as necessary. Key requirements: • supply exceptionally large quantities of air filtered through with high efficiency filters. • dilute and remove the particles and bacteria dispersed from personnel and machinery within the room. • cleanroom is built with materials that do not generate particles • cleanroom personnel use special clothing that minimizes dispersion of particles and micro-organisms. Historical background The first recognition of a need to control the environment during a work operation was in medicine. During the latter part of the 19th century, physicians learned that microorganisms were responsible for transmission of infection. “Operating rooms" were established in an effort to control the spread of infection. The emphasis in the operating room was on sterile conditions or control of biological contamination. Need for cleanrooms • Medicine, pharmaceutical, surgery • Devices for aerospace missions: for ex. the function of a valve in the propellant system of an attitude control device with 10-micron clearances could be impaired by very small particles of contamination. If contamination were to cause the valve to stick partly open, creating a continuing loss of propellant, the attitude control propellant would soon be dissipated, and control of the vehicle would be impossible. The entire mission would fail. • During World War II, the first clean rooms were used in the development of the Norden bombsight and the first navigational gyroscopes. The clearances in these devices were such that if particles in the range of 20 to 50 microns were introduced their function would be impaired. • Today's highly sophisticated electronic, hydraulic, electromechanical, and electro-optical systems require such extreme precision that the presence of microscopic particles of dust cannot be tolerated. In many cases the need for a clean room is obvious. • Semiconductor devices, consumer electronics, optical products Particle size of common pollutants