Cleanroom Terminology

Common Terms

NVR (Nonvolatile Residue)

The quantity of residual molecular and particulate matter remaining following evaporation of a solvent containing contaminants. Compounds which may be NVR sources can come from uncured adhesive components, mold release agents, plasticizers (DOP), oils from motors and bearings, and monomers from tray materials.


Unwanted organic matter that could affect or degrade the performance of devices in a Cleanroom.

FTIR (Fourier Transform InfraRed spectroscopy)

It is an analytical instrument that detects and quantifies molecular acids, bases and solvents of airborne molecular contamination.


Liquid Particle Count is a consistent analytical method. It is to determine the cleanliness by measuring and counting easily releasable particulate contamination on surfaces of disk drive parts in a wetted state under minimal stress conditions.


It is a measurement of the quantity of volatile chemicals released from a material while it is heated. It is to determine the total concentration of volatile organic compounds that outgas from parts, assemblies, components, tapes and adhesive.

Ionic Contamination

The sources of ionic contamination are varied from the drive manufacturing process. Some sources of ionic contaminates: latex gloves, finger cots, cotton Q-tips, foam swabs, particulates, packaging materials, vapor or aerosols and the presence of humans in the manufacturing environment.


Mists from oils, condensed volatiles from other organic materials in time may accumulate on surfaces such as wafers and media.

Solid Particulates

Solid particulates may be from organic, inorganic, metallic or magnetic materials. Examples of solid organic and inorganic particulates: powder from gloves, finger cots, make-up and human debris.


Volatile components from gaskets or adhesives or other sources which outgas may condense upon the media surface causing problems such as stiction, head smear, or corrosive attack of pole tip surfaces.