Method of collecting chemically contaminating impurity constituents contained in air

#The present invention relates to a technique for detection of trace amounts (at a ppb to ppt level in concentration) of water-soluble chemically contaminating impurity constituents contained in air inside a clean room. The invention is suitably applied to a method of detecting chemically contaminating impurity constituents in a gaseous or molecular state, evolved from constituent members of a building used as a clean room of a semiconductor manufacturing plant, or manufacturing equipment installed inside the clean room, chemicals used in a manufacturing process, constituent components of auxiliary facilities such as service supply facilities, humans themselves, and so forth, including, for example, chemically contaminating impurity constituents of acidic, basic, condensate (organic substance) series, and dopant series, and constituents of compounds thereof.

#As for control of contamination on the surface of semiconductor silicon wafers, it has become important to control surface contamination (cleanliness), surface shape, and residual surface distortion (crystallinity). In a manufacturing process at a semiconductor manufacturing plant and a liquid crystal manufacturing plant, besides adverse effects of fine particle contamination and metallic contamination, chemical contamination such as adsorption contamination, chemical reaction contamination, or condensation contamination of chemically contaminating impurity constituents on the surface of silicon wafers and lenses for the manufacturing equipment such as photolitho stepper, acting as factors of deterioration in reliability and yield, has given adverse effects on the surface of products (silicon wafers) processed in a manufacturing process line, thereby causing problems of various quality deteriorations. Examples of factors causing such quality deteriorations include various chemically contaminating substances in gaseous or molecular state, present in air inside the clean room, and evolved from sources of evolution such as the constituent components of the building, the manufacturing equipment, the chemicals used in the manufacturing process, the constituent components of the auxiliary facilities, humans, etc. and compounds thereof.

#More specifically, in the air inside the clean room, there exist not only fine particles but also four species of constituents as chemically contaminating impurity constituents present in mixed state, which can be classified as follows, although this is dependent on variation in process conditions of a manufacturing process line:

#FIGS. 1(a) and 1(b) are schematic views illustrating broadly a first embodiment of the invention, and

#FIG. 2 is a schematic view illustrating broadly a second embodiment of the invention.

#First Embodiment

#FIG. 1(a) is a schematic illustration showing a collection/detection apparatus for carrying out a first embodiment of a detection method according to the invention, for collecting chemically contaminating impurity constituents contained in circulating air inside a clean room for semiconductor manufacturing plants, incorporating the function of collecting the chemically contaminating impurity constituents contained in air. FIG. 1(b) is a schematic illustration showing an overall system wherein the collection/detection apparatus is installed on the inlet side and the outlet side of a chemically contaminating impurity constituent's removal apparatus, respectively.

#As shown in FIG. 1(a), the method for collection and detection is carried out with a system configuration wherein (1) a first collection piping, (2) a first collection vessel containing a first collection liquid, (3) a second collection piping, (4) a third collection piping, (5) a second collection vessel containing a second collection liquid, and (6) a fourth collection piping are disposed in that order sequentially from the upstream side.