Patent Application
20100154837
1. Field of the Invention
The present invention relates to a liquid-scattering prevention cup, surrounding a substrate held by a substrate rotating mechanism, for preventing scattering of a processing liquid coming away from the substrate. The liquid-scattering prevention cup is provided in a substrate processing apparatus which includes the substrate rotating mechanism for holding and rotating a substrate, such as a semiconductor wafer, a glass substrate, a liquid crystal panel, etc., and which supplies a processing liquid to the substrate to process the substrate and, after the processing, rotates the substrate and causes the processing liquid to leave the substrate by the centrifugal force. The present invention also relates to a substrate processing apparatus provided with the liquid-scattering prevention cup, and to a method for operating the substrate processing apparatus.
2. Description of the Related Art
In a semiconductor device manufacturing process, for example, after carrying out copper plating or CMP (chemical mechanical polishing) processing of a surface of a substrate, such as a semiconductor wafer, cleaning of the substrate is generally carried out to remove impurities or contaminants.
A well-known substrate cleaning apparatus (substrate processing apparatus) for carrying out cleaning process of substrates includes a substrate rotating mechanism for horizontally holding and rotating a substrate, and processing liquid supply sections (processing liquid supply nozzles) for supplying a processing liquid, such as a chemical solution or pure water, to a front and back surfaces of the substrate held by the substrate rotating mechanism. This apparatus carries out cleaning of a substrate by supplying the processing liquid while rotating the substrate, and subsequently supplying pure water for rinsing to the substrate. After the cleaning of the substrate, it is common practice to spin-dry the substrate by rotating it at a high speed so as to remove a liquid from the substrate by the centrifugal force.
In such a substrate cleaning apparatus, it is a conventional practice to use a liquid-scattering prevention cup, disposed such that it surrounds a periphery of a substrate held by a substrate rotating mechanism, in order to prevent liquid droplets, which leave the rotating substrate by the centrifugal force during spin-drying, from scattering out over a long distance. While such a conventional liquid-scattering prevention cup can prevent long-distance scattering of liquid droplets, it generally cannot prevent liquid droplets, coming away from a substrate and colliding with an inner surface of the cup, from bouncing off and scattering from the inner surface. The liquid droplets, which have bounced off the inner surface of the liquid-scattering prevention cup, can re-attach to the substrate, which may result in the formation of watermarks on the substrate surface. Such watermarks can cause a leak or poor adhesion in the watermark portion of the substrate, leading to lowering of the product yield. How to reduce the formation of watermarks is therefore an important problem.
A technique for preventing liquid droplets from bouncing off an inner surface of a liquid-scattering prevention cup is known. This technique involves attaching a hydrophilic member to an inner surface of a liquid-scattering prevention cup body so that liquid droplets, which have collided with the inner surface of the liquid-scattering prevention cup body, will be absorbed into the hydrophilic member (see, for example, Japanese Patent Laid-Open Publication No. 2003-100687). Bouncing of liquid droplets on the inner surface of the cup can thus be suppressed.
A PVA sponge, for example, is known to be usable as a hydrophilic member to be attached to an inner surface of a liquid-scattering prevention cup body. Such a member is very soft when it is thin, and therefore, it is very difficult to uniformly and firmly attach such a member to an inner surface of a liquid-scattering prevention cup body having a three-dimensional shape, without producing a wrinkle.
The present invention has been made in view of the above situation in the background art. It is therefore an object of the present invention to provide a liquid-scattering prevention cup, provided in a substrate processing apparatus, which is capable of attaching a hydrophilic member, such as a PVA sponge, to an inner surface of a liquid-scattering prevention cup body easily and efficiently.
It is another object of the present invention to provide a substrate processing apparatus which can keep a layer of a hydrophilic material such as a PVA sponge, provided in an inner surface of a liquid-scattering prevention cup, in a wet state by a wetting section of simple construction, and can prevent liquid droplets from bouncing off the inner surface of the liquid-scattering prevention cup and re-attaching to a substrate surface, and to provide a method for operating the substrate processing apparatus.
In order to achieve the above objects, the present invention provides a liquid-scattering prevention cup, provided in a substrate processing apparatus comprising a substrate rotating mechanism for holding and rotating a substrate, and the liquid-scattering prevention cup, disposed such that it surrounds a periphery of the substrate held by the substrate rotating mechanism, for preventing scattering of liquid droplets coming away from the rotating substrate. The liquid-scattering prevention cup comprises a liquid-scattering prevention cup body, and a liquid-scattering prevention sheet having a surface hydrophilic material layer, attached to an entire area or a predetermined area of the inner surface of the liquid-scattering prevention cup body. The liquid-scattering prevention sheet has been attached to the liquid-scattering prevention cup body by an attachment such that the hydrophilic material layer is exposed.
In a preferred aspect of the present invention, the attachment attaches the opposite side of the liquid-scattering prevention sheet from the hydrophilic material layer to the inner surface of the liquid-scattering prevention cup body with an adhesive.
In a preferred aspect of the present invention, the attachment detachably attaches the opposite side of the liquid-scattering prevention sheet from the hydrophilic material layer to the inner surface of the liquid-scattering prevention cup body by using an attachment jig.
In a preferred aspect of the present invention, the liquid-scattering prevention sheet is comprised of a plurality of liquid-scattering prevention sheet pieces, each having been cut into a predetermined shape adapted for close contact with the inner surface of the liquid-scattering prevention cup body, and each comprising a resin sheet and the surface hydrophilic material layer attached to the resin sheet via an adhesive.
In a preferred aspect of the present invention, the liquid-scattering prevention sheet has been cut into a predetermined shape adapted for close contact with the inner surface of the liquid-scattering prevention cup body, comprises an elastic sheet and the surface hydrophilic material layer attached to the elastic sheet via an adhesive, and has been attached to the inner surface of the liquid-scattering prevention cup body by inserting it into the liquid-scattering prevention cup body through elastic deformation of the liquid-scattering prevention sheet, and bringing the elastic sheet into close contact with the inner surface of liquid-scattering prevention cup body through the elastic restoring force of the elastic sheet.
In a preferred aspect of the present invention, the liquid-scattering prevention sheet, attached to the inner surface of the liquid-scattering prevention cup body, has a seam which is inclined from the vertical direction of the liquid-scattering prevention cup body toward a direction opposite to the rotating direction of the substrate rotating mechanism.
The present invention also provides a substrate processing apparatus comprising a substrate rotating mechanism for holding and rotating a substrate, and a liquid-scattering prevention cup, disposed such that it surrounds the periphery of the substrate held by the substrate rotating mechanism, for preventing scattering of a liquid coming away from the rotating substrate. A hydrophilic material layer for preventing liquid droplets, coming away from the rotating substrate, from bouncing off the inner surface of the liquid-scattering prevention cup is provided in part or all of the inner surface of the liquid-scattering prevention cup. The substrate processing apparatus further includes a wetting section for supplying a rinsing liquid to the hydrophilic material layer to keep the hydrophilic material layer in a wet state.
In a preferred aspect of the present invention, the wetting section includes a plurality of rinsing liquid spray nozzles disposed such that the rinsing liquid is uniformly supplied to a surface of the hydrophilic material layer.
The rinsing liquid spray nozzles may be disposed below the liquid-scattering prevention cup.
Alternatively, the rinsing liquid spray nozzles may be disposed in the vicinity of the liquid-scattering prevention cup.
Preferably, the rinsing liquid spray nozzles are each provided with a spray angle adjustment mechanism for adjusting the angle of spray of the rinsing liquid to adjust the position of a spray spot on the surface of the hydrophilic material layer.
The present invention also provides a method for operating a substrate processing apparatus comprising a substrate rotating mechanism for holding and rotating a substrate, and a liquid-scattering prevention cup, disposed such that it surrounds the periphery of the substrate held by the substrate rotating mechanism, for preventing scattering of a liquid coming away from the rotating substrate. The method comprises providing in part or all of an inner surface of the liquid-scattering prevention cup a hydrophilic material layer for preventing liquid droplets, coming away from the rotating substrate, from bouncing off the inner surface of the liquid-scattering prevention cup, and supplying a rinsing liquid from a rinsing liquid supply section to the hydrophilic material layer during idling of the apparatus to keep the hydrophilic material layer in a wet state.
Preferably, the rinsing liquid supply section includes a rinsing liquid spray nozzle.
According to the liquid-scattering prevention cup of the present invention, the liquid-scattering prevention sheet having a surface hydrophilic material layer is attached by an attachment to an entire area or a predetermined area of the inner surface of the liquid-scattering prevention cup body such that the hydrophilic material layer is exposed. This makes it possible to easily and closely attach the hydrophilic material to the inner surface of the liquid-scattering prevention cup body having a three-dimensional curve even when the hydrophilic material is a thin sheet-like member, such as a PVA sponge.
The liquid-scattering prevention sheet, attached to the inner surface of the liquid-scattering prevention cup body, may have a seam which is inclined from the vertical direction of the liquid-scattering prevention cup body toward a direction opposite to the rotating direction of the substrate rotating mechanism. This can reduce bouncing of a processing liquid on the seam of the liquid-scattering prevention sheet.
According to the substrate processing apparatus of the present invention, the provision of the wetting section can keep the hydrophilic material layer, provided in the inner surface of the liquid-scattering prevention cup, in a wet state during idling of the substrate processing apparatus and can thereby prevent drying of the hydrophilic material layer. At the start of processing of a substrate, liquid droplets, coming away from the substrate, collide with the soft hydrophilic material layer in a wet state and are absorbed into the layer, whereby bouncing of the liquid droplets on the layer can be suppressed. Therefore, re-attachment of liquid droplets, bouncing off the hydrophilic material layer, to the substrate can be reduced.
According to the method for operating a substrate processing apparatus of the present invention, a rinsing liquid is supplied from the rinsing liquid supply section to the hydrophilic material layer during idling of the apparatus to keep the hydrophilic material layer in a wet state. This can prevent liquid droplets, coming away from a substrate, from bouncing off the hydrophilic material layer and re-attaching to the substrate during processing of the substrate.
Preferred embodiments of the present invention will now be described with reference to the drawings.
As shown in
The sheet material 13 is not limited to a PVC sheet: A resin sheet (having a water absorption rate of not more than 0.5%), such as PET, polyacrylate, PEEK, PP, PE, etc., may be used. The hydrophilic material is not limited to a PVA sponge: Any water-retentive, highly water-absorptive resin material having a hydrophilic group, such as a polyurethane sponge, may be used. The adhesive 14 for bonding the sheet material 13 to the inner surface of the liquid-scattering prevention cup body 11 is not limited to a synthetic adhesive, such as an acrylic resin adhesive: It is possible to use a natural adhesive. An elastic material is preferably used as the sheet material 13, as will be described later.
As shown in
The single long liquid-scattering prevention sheet 16a, which has been cut into a predetermined shape adapted for close contact with the inner surface of the liquid-scattering prevention cup body 11 having a three-dimensional curve, is rolled and inserted into the liquid-scattering prevention cup body 11, and the rolled liquid-scattering prevention sheet 16a is expanded in the liquid-scattering prevention cup body 11. By the elastic restoring force of the sheet material 13 of the liquid-scattering prevention sheet 16a, the sheet material 13 comes into close contact with the inner surface of the liquid-scattering prevention cup body 11. This facilitates attachment of the liquid-scattering prevention sheet 16a to the inner surface of the liquid-scattering prevention cup body 11 by an adhesive or an attachment jig. When the sheet material 13 has a strong elastic restoring force, the liquid-scattering prevention sheet 16a can be attached to the inner surface of the liquid-scattering prevention cup body 11 only by the elastic restoring force of the sheet material 13 or by using a simple attachment jig.
It is a very difficult work to attach a thin PVA sponge sheet, e.g., having a thickness of 3 mm, directly and uniformly to the inner surface of the liquid-scattering prevention cup body 11. According to the present invention, the hydrophilic material attachment work can be made significantly easier by using the liquid-scattering prevention sheet 16 which is comprised of either a single sheet or a plurality of sheet pieces, having a predetermined shape adapted for close contact with the inner surface of the liquid-scattering prevention cup body 11, and which has been prepared by bonding and attaching a PVA sponge sheet to the resin sheet material 13, for example, a PVC sheet having a thickness of 0.5 mm, and bonding and mounting the liquid-scattering prevention sheet 16 to the inner surface of the liquid-scattering prevention cup body 11 with the adhesive 14.
Reference numeral 25 denotes a pivot arm. To one end of the pivot arm 25 are mounted a gas supply nozzle 26 for supplying a dry gas (IPA gas) G1 to the substrate Wf held on the spinning wheel 24, a liquid supply nozzle 27 for supplying a liquid W1 to the substrate Wf, and a cover rinsing nozzle 36 for supplying a rinsing liquid W2 to the substrate Wf for covering the substrate Wf with the rinsing liquid W2. The other end of the pivot arm 25 is supported by a pivot shaft 29. The pivot arm 25 is configured to move the gas supply nozzle 26, the liquid supply nozzle 27 and the cover rinsing nozzle 36 in the radial direction of the substrate Wf. Reference numeral 28 denotes an upper substrate surface rinsing nozzle for supplying a rinsing liquid W3 to an upper surface of the substrate Wf held by the holding members 23 of the spinning wheel 24, and reference numeral 31 denotes a lower substrate surface rinsing nozzle for supplying a rinsing liquid W4 to a lower surface of the substrate Wf.
Each cup-rinsing nozzle 34 is connected to one of pipes 35, 35; and the rinsing liquid W5 is sprayed from each cup-rinsing nozzle 34 toward the hydrophilic material layer 12 in the inner surface of the liquid-scattering prevention cup 10 by supplying the rinsing liquid W5 to the pipes 35, 35. Each cup-rinsing nozzle 34 is capable of adjusting the angle α of spray of the rinsing liquid W5 so that the position of a spray spot on the hydrophilic material layer 12 can be adjusted. The rinsing liquid W5 may preferably be supplied to an upper or top portion of the hydrophilic material layer 12: Because of penetration of the rinsing liquid into the hydrophilic material layer 12 as well as downward flow of the rinsing liquid, the hydrophilic material layer 12 can be wetted uniformly in a short time by supplying the rinsing liquid to the upper or top portion of the hydrophilic material layer 12.
The pivot arm 25 is disposed in an upper position in the cleaning tank 21. To the pivot arm 25 are mounted a gas supply nozzle 26 for jetting a dry gas toward a substrate Wf held on the spinning wheel 24, and a water supply nozzle 27 for spraying water toward the substrate Wf. The gas to be jetted from the gas supply nozzle 26 typically is an inert gas, such as nitrogen gas. The gas may contain the vapor of a substance which, when dissolved in water, lowers the surface tension. Such a substance may be exemplified by a hydrophilic solvent, such as isopropyl alcohol (IPA), diacetone alcohol, ethyl glycol, ethyl acetate or methylpyrrolidone, or a mixture thereof. Water to be supplied from the water supply nozzle 27 typically is pure water. Depending on the intended purpose, however, it is possible to use deionized water, carbon dioxide-containing water or functional water (hydrogen-containing water, ion-containing water, etc.), from which dissolved salts or dissolved organic matter maybe removed, or an alcohol, such as IPA, or an organic solvent.
The upper substrate surface rinsing nozzle 28 is a nozzle for spraying a rinsing liquid onto the upper surface of the substrate Wf held on the spinning wheel 24, and the cup-rinsing nozzles 34 are nozzles for cleaning the inner surface of the liquid-scattering prevention cup 10. The cup-rinsing nozzles 34 may be disposed to another place of the liquid-scattering prevention cup 10, such as near the inner surface of the liquid-scattering prevention cup body 11, or near the inwardly inclined portion 10a. Although not shown diagrammatically, a lower substrate surface rinsing nozzle for spraying a rinsing liquid onto the lower surface of the substrate Wf is also provided. As with the water to be supplied from the water supply nozzle 27, pure water, deionized water, carbon dioxide-containing water, an alcohol such as IPA, an organic solvent, etc. can be used as the rinsing liquid to be supplied from the lower substrate surface rinsing nozzle. The cleaning tank 21 is provided with a transfer port 21a for carrying in and out a substrate, and a shutter 30 for opening and closing the transfer port 21a.
Next, as shown in
Next, as shown in
The drying process is completed in about 40 seconds. Upon completion of the drying process, the supply of the IPA gas G1 and the rinsing liquid W2 from the gas supply nozzle 26 and the water supply nozzle 27 is stopped, as shown in
After completion of the drying process for the lower surface of the substrate Wf, the liquid-scattering prevention cup 10 is lowered and, at the same time, the shutter 30 is lowered to open the transfer port 21a of the cleaning tank 21, as shown in
Because the rinsing liquid W5 is continually supplied from the cup-rinsing nozzles 34 to the hydrophilic material layer 12 in the inner surface of the liquid-scattering prevention cup 10 during idling of the substrate cleaning apparatus 20, as described above, the hydrophilic material layer 12 can be kept wet without drying. When the substrate processing apparatus 20 ceases idling and enters into processing (cleaning) of a substrate Wf, liquid droplets, coming away from the substrate Wf, collide with the hydrophilic material layer 12 in the inner surface of the liquid-scattering prevention cup 10. The liquid droplets are then absorbed into the soft hydrophilic material layer 12 in a wet state. Bouncing of the liquid droplets on the layer is thus suppressed, and therefore re-attachment of the liquid droplets to the substrate Wf can be reduced.
As described hereinabove, by attaching the liquid-scattering prevention sheet 16, having the surface hydrophilic material layer 12, to the inner surface of the liquid-scattering prevention cup body 11 such that the hydrophilic material layer 12 is exposed inside the liquid-scattering prevention cup 10, and keeping the hydrophilic material layer 12 in a wet state, droplets of a rinsing liquid, coming away from a substrate Wf and colliding with the inner surface of the liquid-scattering prevention cup 10 during the drying process for the upper substrate surface or the drying process (spin-drying) for the lower substrate surface, are absorbed into the hydrophilic material layer 12 in a wet state, whereby bouncing of the liquid droplets on the inner surface of the liquid-scattering prevention cup 10 can be suppressed. This can significantly reduce re-attachment of the rinsing liquid to the dried substrate Wf.
In the liquid-scattering prevention cup 10 shown in
For example, it is possible to attach a single liquid-scattering prevention sheet 16a, which has been cut into a predetermined shape, as shown in
In the above embodiments, the liquid-scattering prevention sheet 16a or the liquid-scattering prevention sheet pieces 16-1, 16-2, 16-3 . . . , are attached to the inner surface of the liquid-scattering prevention cup body 11 by bonding the sheet material 13 to the inner surface of the liquid-scattering prevention cup body 11 with the adhesive 14. However, the liquid-scattering prevention sheet 16 may be attached to the liquid-scattering prevention cup body 11 by various other methods than the use of an adhesive, including the methods shown in
The attachment method shown in
Sheet holding jigs 41 for holding the lower end of the liquid-scattering prevention sheet 16 are attached to predetermined positions on the inner surface of the liquid-scattering prevention cup body 11. The sheet material 13 of the liquid-scattering prevention sheet 16, which has been cut into a predetermined shape adapted for close contact with the inner surface of the liquid-scattering prevention cup body 11, is pressed against the inner surface of the liquid-scattering prevention cup body 11 such that the hydrophilic material layer 12 faces inwardly of the liquid-scattering prevention cup 10, and the upper end of the liquid-scattering prevention sheet 16 is secured to the upper end of the liquid-scattering prevention cup body 11 with clips 42. The liquid-scattering prevention sheet 16 can thus be attached to the inner surface of the liquid-scattering prevention cup body 11 such that the hydrophilic material layer 12 is exposed.
The attachment method shown in
The sheet material 13 of the liquid-scattering prevention sheet 16, which has been cut into a predetermined shape adapted for close contact with the inner surface of the liquid-scattering prevention cup body 11 in an area ranging from the upper end to a predetermined lower position, is pressed against the inner surface of the liquid-scattering prevention cup body 11 such that the hydrophilic material layer 12 faces inwardly of the liquid-scattering prevention cup 10, and the liquid-scattering prevention sheet 16 are secured to the liquid-scattering prevention cup body 11 with screws 43. The liquid-scattering prevention sheet 16 can thus be attached to the inner surface of the liquid-scattering prevention cup body 11 such that the hydrophilic material layer 12 is exposed.
The attachment method shown in
Bolts 45 are attached to the sheet material 13 of the liquid-scattering prevention sheet 16, which has been cut into a predetermined shape adapted for close contact with the inner surface of the liquid-scattering prevention cup body 11 in an area ranging from the upper end to a predetermined lower position. The bolts 45 are inserted into bolt holes formed in the inner surface of the liquid-scattering prevention cup body 11 with the hydrophilic material layer 12 facing inwardly of the liquid-scattering prevention cup 10, and nuts 44 are engaged with the tips of the bolts 45, projecting from the outer surface of the liquid-scattering prevention cup body 11, and the nuts 44 are tightened. The liquid-scattering prevention sheet 16 can thus be attached to the inner surface of the liquid-scattering prevention cup body 11 such that the hydrophilic material layer 12 is exposed.
By detachably attaching the liquid-scattering prevention sheet 16 to the inner surface of the liquid-scattering prevention cup body 11 by using an attachment jig, as shown in
As described above, the liquid-scattering prevention cup body 11 is generally cylindrical and has an inwardly inclined portion 10a at its upper end. Although in this embodiment the upper end and the lower end of the cylindrical portion of the liquid-scattering prevention cup body 11 have the same diameter, the diameter of the lower end may be slightly larger than the diameter of the upper end, as described above. In consideration of such shape of the liquid-scattering prevention cup body 11, the liquid-scattering prevention sheet 16 has been cut into such a shape as not produce a gap between the sheet material 13 of the liquid-scattering prevention sheet 16 and the inner surface of the liquid-scattering prevention cup body 11. Further, the sheet material 13, to which a PVA sponge is attached, is an elastic resin material such as PVC. Accordingly, when the liquid-scattering prevention sheet 16 is rolled and inserted into the liquid-scattering prevention cup body 11 and expanded in the liquid-scattering prevention cup body 11, the liquid-scattering prevention sheet 16, through the elastic restoring force of the sheet material 13, makes close contact with the inner surface of the liquid-scattering prevention cup body 11. This facilitates attachment of the liquid-scattering prevention sheet 16 to the inner surface of the liquid-scattering prevention cup body 11 by an adhesive or an attachment jig. When the sheet material 13 has a strong elastic restoring force, the liquid-scattering prevention sheet 16 can be attached to the inner surface of the liquid-scattering prevention cup body 11 only by the elastic restoring force of the sheet material 13 or by additionally using a simple attachment jig.
Although in the liquid-scattering prevention cup 10 shown in
Such an inclined seam 17′ can reduce bouncing of a rinsing liquid on the seam 17′, thereby reducing the formation of watermarks on a surface of a substrate Wf.
Watermarks 101 formed on a semiconductor wafer Wf can cause a leak or poor adhesion in the watermark portion of the semiconductor wafer Wf, leading to lowering of the product yield. The substrate processing apparatus and the method for operating the apparatus, according to the present invention, can significantly reduce the formation of watermarks 101, and can therefore considerably increase the product yield.
While the present invention has been described with reference to the embodiments thereof, it will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described above, but it is intended to cover modifications within the general inventive concept described herein. For example, while the present invention has been described with reference to the substrate cleaning apparatus for cleaning a semiconductor wafer, the liquid-scattering prevention cup, the substrate processing apparatus using the liquid-scattering prevention cup and the method for operating the apparatus, according to the present invention, can also be applied to a cleaning apparatus for a substrate other than a semiconductor wafer, such as a glass substrate, a liquid crystal panel, etc. Further, the present invention is not limited to a substrate cleaning apparatus, but is applicable to any substrate processing apparatus that includes a substrate rotating mechanism for holding and rotating a substrate, and carries out processing of the substrate by supplying a processing liquid to the rotating substrate.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2008-327331 | Dec 2008 | JP | national |
