Organic particulate contamination

Particulate contamination This class of contaminants includes organic, metallic solid, and inorganic solid contaminants. These contaminants are discussed in the following paragraphs. 

Whether the substrate is bulk Si or SOI, the most critical step in IC fabrication is the initial cleaning of the wafer. The RCA clean procedure is the industry standard, consisting of the following complex treatment to remove both organic and inorganic contaminants. It should be noted that these procedures are performed within a clean room, to avoid particulate contamination ... 

Level of cleanliness required Type and amount of organic contaminant Type, size, composition and amount of particulate contaminant Co-solvent requirements Type of parts to be cleaned (e.g., size, complexity, porosity, loading density, pressure sensitivity) Production capacity Breadth of application Temperature, pressure, separator efficiency, cycle time Temperature, pressure, co-solvents Flow rate, agitation, filtration Type, quantity, emission control and recycle considerations Dimensions, fixturing and flow pattern within cleaning vessel process control strategy Parts per cycle and cycles per work period Number of different processes that must be performed by the system... 

Figure 2.13 Atomic force micrographs of (a) the surface of Cu cleaned with dilute organic acid after CMP (the surface is free of particulates but dendrites are observed in certain lines) and (b) the surface of Cu cleaned with deionized water after CMP (particulate contamination is...

Water, deionized (DI) (cleaning) Water in which most of the ions, which have a potential for reaction with cleaning materials and/or leaving a residue, have been removed. Often used (erroneously) synonymously with pure water or ultrapure water this is incorrect since DI water can still have organic and particulate contamination. For deionized water the electrical conductivity can be as low as 18.2megohm-cm at room temperature. See also Conductivity Water, ultrapure. 

Environmental Aspects. Airborne particulate matter (187) and aerosol (188) samples from around the world have been found to contain a variety of organic monocarboxyhc and dicarboxyhc acids, including adipic acid. Traces of the acid found ia southern California air were related both to automobile exhaust emission (189) and, iadirecfly, to cyclohexene as a secondary aerosol precursor (via ozonolysis) (190). Dibasic acids (eg, succinic acid) have been found even ia such unlikely sources as the Murchison meteorite (191). PubHc health standards for adipic acid contamination of reservoir waters were evaluated with respect to toxicity, odor, taste, transparency, foam, and other criteria (192). BiodegradabiUty of adipic acid solutions was also evaluated with respect to BOD/theoretical oxygen demand ratio, rate, lag time, and other factors (193). 

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