Cleaning and liquid contact with solids – Apparatus – Miscellaneous
Reexamination Certificate
1999-05-24
2001-02-20
Coe, Philip R. (Department: 1746)
Cleaning and liquid contact with solids
Apparatus
Miscellaneous
C134S184000, C134S902000
Reexamination Certificate
active
06189552
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for processing substrates, and includes a receptacle containing a processing fluid and at least one substrate support, whereby the components of the receptacle and/or of the substrate support that come into contact with the processing fluid have a protective layer, and whereby guide and/or support elements for the substrates are fused onto the protective layer.
An apparatus of this type is known from WO 95/02473 A1.
Further apparatus for processing substrates, especially semiconductor wafers, are known from the publications DE 44 13 077 A1, and DE 195 46 990 A1 of the present applicant, and are furthermore described in the not yet published German Patent applications DE 196 16 402.8, DE 196 15 969.5, DE 196 37 875.3, DE 196 44 253.2 and DE 196 44 254.0. Receptacles or substrate supports made of metal, for example stainless steel, are coated with a protective layer that not only protects the receptacle wall and the substrate supports from corrosive processing fluid, but also prevents the processing fluid from being contaminated by metallic parts.
JP 6-28 34 86 A2 or DE 39 30 056 A1 disclose wafer cassettes or wafer baskets for transporting and supporting wafers, with guide and support elements being provided that have a shape or are rounded in order during introduction and removal of the wafers to avoid damage thereto. The publications JP 4-130 724 A1 and JP 6-204 197 A2 show wafer cleaning apparatus where the processing receptacle or the wafer support is made of quartz.
It is an object of the present invention to provide an apparatus for processing substrates that in particular with regard to the guide and support elements for the substrates in the receptacle is optimally configured and can be economically manufactured, and in addition has a long service life.
SUMMARY OF THE INVENTION
The stated objective is inventively realized in that the guide elements are formed of polymeric strands that are fused with the protective layer and with one another.
As a consequence of the inventive measure of fusing onto the protective layer guide and/or support elements for the substrates in the form of strands, the manufacture of such apparatus is particularly simple and economical. It is now also possible to choose receptacles of metal that are significantly more economical than receptacles made of high-purity quartz. This also avoids the problem of unreliable coating of a protective layer in angular or sharply tapered areas where the protective layer can be damaged particularly easily.
The protective layer for the protective film, which has a thickness of, for example, 1 mm, is preferably made of perfluoroalkoxy polymers (PFA).
Plastic guide elements for the substrates are advantageously fused onto the protective layer on oppositely disposed inner surfaces of the coated receptacle walls. This is considerably more cost-effective than quartz receptacles that are equipped with appropriate guide elements. Furthermore, a particle producing friction of the substrates of the relatively rough quartz is avoided. It is now possible to also use a metal, such as stainless steel or aluminum, as the base material for the receptacle.
Pursuant to one advantageous specific embodiment of the invention, the guide members comprise plastic strips that are glued or fused onto the inner walls of the fluid receptacle, respectively being disposed opposite one another.
The plastic strips preferably have a thickness that corresponds to the height of the guide members.
Pursuant to a further specific embodiment of the invention, the plastic strands have a diameter of, for example, 4 mm. They are fused with the protective layer and with one another in order to form appropriate guide members. The shape of the guide members is then achieved by rounding off or smoothing the edges of the strands.
If guide slots for the substrates are not formed by guide members that are appropriately spaced from one another, it is particularly advantageous to form guide slots for the substrates in appropriately wide plastic strips or plastic strips formed from plastic strands. The spacings between the guide slots, which are equidistant relative to one another, are selected in conformity with the packing thickness of the substrate packings provided for the fluid processing.
The guide members for the substrates, in other words the fused-on plastic strips or strands, are advantageously comprised of the same material as is the protective layer. This is advantageously PFA.
It is very advantageous to configure the guide slots in a V-shape in the introduction and withdrawal region for the substrates so that the introduced substrates are centered toward the actual guide and support region and in the entry area do not hit against the guide members. The V-shaped introduction and removal areas for the substrates furthermore have the advantage that in this way the rinsing and flow through with the processing fluid, for example with a rinsing agent, is improved.
As a consequence of inventively providing a protective layer on the receptacle walls that come into contact with the processing fluid, and fusing guide and support elements on this protective layer, it is now also possible to use metal, preferably stainless steel or aluminum, as the base material for the receptacle walls or for the entire receptacle. This results not only in considerably lower manufacturing costs but also a longer service life, because conventional receptacles are made of quartz and the service life of quartz in conjunction with the processing fluid that is used, for example, for semiconductor wafers, is limited.
Pursuant to a further specific embodiment of the invention, the receptacle is made of quartz despite the presence of a protective layer and the inventive possibility of fusing guide and support elements for the substrates onto the protective layer. This is particularly advantageous when a reliable and smooth-running substrate processing must be ensured even if the protective layer is damaged for some reason, so that in the event of steel or aluminum receptacles the processing fluid could be contaminated. This danger does not exist with quartz receptacles, even when the protective layer is damaged. However, due to the presence of the protective layer the quartz receptacle has a significantly longer service life than do conventional apparatus.
Pursuant to a particularly advantageous specific embodiment of the present invention, the substrate support is a metal strip that according to the invention is coated with a protective layer and onto which, after the coating with a protective layer, is fused a blade-like plastic substrate support or receiving element. Since pursuant to the present invention a metal strip can also be used, since the blade-like plastic receiving element can be fused despite the fact that it is coated with a protective layer, the substrate support can be very narrow and thus allows optimum flow conditions. It is therefore no longer necessary to provide measures for improving the flow conditions about the substrate support, as this is described in the not previously published German Patent application 196 44 254.0.
Instead of fusing the blade-like plastic substrate receiving element onto the metallic substrate support that is coated with a protective layer, it is also possible pursuant to a further embodiment of the invention to place or slip the substrate receiving element onto the substrate support as a cap.
The blade-like substrate receiving elements are preferably provided with uniformly spaced notches for the substrates in order to be able to equidistantly space the substrates relative to one another on the substrate support.
Pursuant to a particularly advantageous specific embodiment of the substrate support, at least one stabilization element is provided that is disposed parallel to the substrate support and is connected thereto. In this way it is further possible to make the actual substrate support, on which the substrates are supported, even narrower and hence more aer
Coe Philip R.
Robert W. Becker & Associates
Steag MicroTech GmbH
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