Contamination is a process or act that causes materials or surfaces to be soiled with contaminating substances. There are two broad categories of surface contaminants: film type and particulates. These contaminants can produce a “killer defect” in a miniature circuit. Film contaminants of only 10 nm (nanometers) can drastically reduce coating adhesion on a wafer or chip. It is widely accepted that particles of 0.5 microns or larger are the target. However, some industries are now targeting smaller particles.
A partial list of contaminants is found below. Any of these can be the source for killing a circuit. Preventing these contaminants from entering the cleanroom environment is the objective. It requires a commitment by everyone entering the cleanroom to make it happen. Professional cleaning personnel need to be aware of the importance of controlling contaminants. Strict procedures should be followed whenever entering or cleaning a cleanroom. Compromise is not acceptable when cleaning in a cleanroom.
Sources of Contamination
This is a partial list of some of the commonly known contaminants that can cause problems in some cleanroom environments. It has been found that many of these contaminants generate from five basic sources. The facilities, people, tools, fluids and the product manufactures can all contribute to contamination. Review this list to gain a better understanding of where contamination originates.
1.Facilities
Walls, floors and ceilings; Paint and coatings; Construction material (sheet rock, saw dust etc.) ; Air conditioning debris; Room air and vapors; Spills and leaks
2.People
Skin flakes and oil; Cosmetics and perfume ; Spittle Clothing debris (lint, fibers etc.); Hair
3.Tool Generated
Friction and wear particles; Lubricants and emissions; Vibrations; Brooms, mops and dusters
4.Fluids
Particulates floating in air; Bacteria, organics and moisture; Floor finishes or coatings; Cleaning chemicals; Plasticizers (outgasses); Deionized water
5.Product generated
Silicon chips; Quartz flakes; Clean room debris; Aluminum particles
