Electricity: electrical systems and devices – Discharging or preventing accumulation of electric charge
Patent
1994-01-24
1997-01-21
Fleming, Fritz
Electricity: electrical systems and devices
Discharging or preventing accumulation of electric charge
361213, H05F 306
Patent
active
055964788
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to an apparatus for neutralizing charges on bodies which are extremely easily charged and for which it is necessary to avoid a charge, such as processed substrates represented by substrates (wafers) in manufacturing processes of, for example, semiconductor devices, liquid crystal plates in manufacturing processes of flat display apparatuses, EL glass plates and the like.
BACKGROUND ART
In the manufacture of semiconductor devices or flat plate displays, various substrate processing apparatuses (thin film formation apparatuses for forming prespecified thin films on the processed substrate, impurity addition apparatuses for conducting the addition or impurities such as boron, phosphorous, arsenic, and the like) are employed; however, a composition in which all processing apparatuses are built into a single chamber is rare, and it is generally the case that the processing apparatuses are compartmentalized through the medium of a conveyance path under atmospheric pressure or a conveyance passage (tunnel chamber), or via opening and closing mechanisms, from other processing chambers.
However, since the instances of various types of handling of the processed substrates, such as gripping, moving, and the like, are frequent, and particularly since the implements and the like which come into contact with the processed substrate at the time of such handling are normally formed using fluorine resin or silica insulating film or the like in order to avoid metallic contamination of or damage to the processed substrates, the processed substrate is positively (in some cases, negatively) charged as a result of the electrification rank relationship thereof with respect to the implements at the time of contact, and the potential of these processed substrates easily becomes high.
In addition, In order to prevent the depositting of dust on the processed substrate, a gas flow which bas been passed through a filter is normally caused to flow in the vicinity of the processed substrate, and because floating particles, water, and trace amounts of gaseous impurities and the like, even if in very small amounts, are contained in this gas flow, dust is actively deposited on the charged processed substrate, or the interior of the processing apparatus is contaminated. Furthermore, with respect to the conveyance of the processed substrate between apparatuses, the processed substrate is commonly first transferred to a pretreatment chamber and placed on a prespecified installation platform, and is then transferred to a reaction chamber.
In this case, during the transfer of the processed substrates, instances in which the gripping, rubbing, or the like of the processed substrates by means of the handling mechanisms are frequent, and furthermore, the implements comprising the handling mechanisms are normally formed using fluorine resins, silica, or the like in order to avoid metallic contamination of the processed substrates, so that as a result of the electrification rank relationship of the processed substrate with respect to the implements, the processed substrate is positively charged, and easily attains a high potential.
The following methods are commonly known for the prevention of the charging of processed substrates and processed substrate carriers, that is to say, as charge removal mechanisms; first, a method employing an ionizer, that is to say, a method in which corona discharge is generated in an ambient atmosphere in which a processed substrate or a processed substrate carrier is placed, and by means of this, the generated ions and the charges are neutralized,
secondly, a method in which the processed substrate is subjected to handling by means of a resin material in which a grounded metallic body or a grounded conductive substance (carbon, metal, or the like) is included, and charges are thus neutralized, and the like.
However, in the first conventional method above, corona discharge in an ambient atmosphere Is employed, so that the generation of electromagnetic noise as a result
REFERENCES:
patent: 4827371 (1989-05-01), Yost
patent: 5255153 (1993-10-01), Nozawa et al.
Inaba Hitoshi
Ohmi Tadahiro
Fleming Fritz
Ohmi Tadahiro
Takasago Netsugaku Kogyo Kabushiki-Kaisha
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