Treatment device for disk-like substrates

The invention relates to an arrangement for treating disk-shaped objects, in particular silicon wafers, with a carrier for the disk-shaped object, to which carrier is assigned a drive for rotating the carrier about its axis, with lines opening above the carrier, for supplying at least one treatment fluid and one Rinsing fluids, and with a hood arranged above the carrier, to which a line for supplying an inert gas, for example nitrogen, is connected to the interior of the hood.

In certain methods for treating (silicon) wafers, problems occurred in particular when rinsing the wafers after they had been treated with a treatment medium, for example with an etching fluid, in that spots formed on the surface of the wafer. These spots arise when the (silicon) surface is oxidized in the presence of water and oxygen.

An arrangement of the type mentioned at the beginning is known from US Pat. No. 5,487,398. In this known arrangement, the hood serves to tightly close a container designed as a closed vessel, in which the carrier for the disk-shaped object is accommodated, in the region of its opening located above the carrier. In this case, nitrogen can be fed in via a line connected to the hood, even before the hood tightly closes the container. The disadvantage of the known arrangement is that the hood is arranged at a considerable distance from the disc-shaped object or the carrier holding it, so that undesirable turbulence and uncontrolled flows of the treatment fluids and the rinsing fluids can result in the container.

The invention is based on the object of avoiding the formation of such “water stains” with simple means.

This object is achieved in an arrangement of the type mentioned in that the hood is arranged to completely cover the object held on the carrier, and that an annular gap for the between the carrier or the object held on it and the lower end of the hood Treatment fluid and inert gas emerge.

Because a hood is arranged on the upper side of the carrier for the disk-shaped object (wafer), which is exposed to an inert gas, e.g. nitrogen, the air that causes the formation of water spots is removed from the process space directly above the disk-shaped object (silicon wafer ) repressed.

The fact that in the invention the hood is designed independently of the carrier for the disk-shaped object, that is to say can stand still, results in a simple construction, although the supply of the process fluids and the inert gas is readily possible. In the case of the invention, the supplied inert gas and supplied treatment fluids are applied through the hood, the supplied inert gas displacing undesired air.

In the arrangement according to the invention, the design and construction of the carrier for the disk-shaped object (silicon wafer) is not essential. Any, including known constructions of such carriers can be used.

It is of particular advantage in the arrangement according to the invention that the rotating carrier acts in the manner of a centrifugal pump because of the mutual association of hood and carrier and produces a negative pressure inside the hood which is advantageous for the cleaning effect. It is up to you to set the pressure with which the inert gas is supplied to the optimal value for the desired cleaning effect by selecting the speed of the carrier and the width of the annular gap between the hood and the carrier.

In a particularly simple and practical embodiment, the arrangement according to the invention is characterized in that the hood, as is known per se, is arranged coaxially to the carrier.

In a practical embodiment of the invention it can be provided that the hood is held by a hollow support tube through which the lines for supplying the treatment fluid and the rinsing fluid are led into the upper part of the hood. This embodiment of the arrangement according to the invention is characterized by a simple construction and nevertheless protects the disk-shaped object from undesired access of atmospheric oxygen during its treatment.

The distribution of inert gas in the interior of the hood is particularly uniform if, according to a proposal of the invention, a nozzle arrangement with several in the upper part of the hood

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Nozzles are provided for the outlet of inert gas supplied via the hollow support tube.

With a similar, advantageous effect in a modified embodiment of the arrangement according to the invention it can be provided that the hood is closed at its end facing the carrier or the object by a wall that holes are provided in the wall through which inert gas from the hood in the space between the wall and the disc-shaped object can escape. In this embodiment, the defined space between the wall of the hood and the object held on the carrier has a favorable effect on preventing the entry of atmospheric oxygen.

The last-mentioned embodiment can also be characterized in that the support tube extends up to the wall and that the lines for supplying the treatment fluid and the rinsing fluid open out on the side of the wall facing the support. In this embodiment, a spatially particularly favorable and easy to manufacture construction is achieved.

Further details, features and advantages of the invention emerge from the following description of two exemplary embodiments of the arrangement according to the invention.

It shows: FIG. 1 a first embodiment schematically in side view, partially in section, and FIG. 2 another embodiment in the same view.

In the embodiment shown in FIG. 1, a cover 5, which is approximately bell-shaped in the embodiment, is arranged above a carrier 1, which is carried by a shaft 2 and is rotatable about its axis 3 by a drive assigned to the shaft 2. The bell-shaped hood 5 is arranged over the carrier 1 in such a way that a (silicon) wafer 4 held on it is completely covered by the lower, open end 6 of the hood 5. An annular gap 7 is present between the carrier 1 and the wafer 4 on the one hand and the bell-shaped hood 5 on the other hand.

In the area of ​​the upper end B of the hood 5, this is connected to a hollow support tube 9, through which lines 10, 11 lead to the supply of media. Specifically, in the embodiment shown in Fig. 1, (at least) one line 10 for supplying a treatment fluid and a line 11 for supplying a rinsing medium, for example deionized water, are provided, both of which are in the area of ​​the upper end 8 of the hood 5 Space 12 enclosed by the hood 5 open out. Through the hollow support tube 9, nitrogen is also supplied as an inert gas, which exits in the area of ​​the upper end 8 of the hood 5 through a nozzle arrangement 13 into the space 12 in the hood 5. The nozzles 14 of the nozzle arrangement 13 are aligned in such a way that nitrogen emerges approximately radially from the nozzle arrangement 13 and fills the entire space 12 evenly with nitrogen in order to displace air from the space 12.

The embodiment of the arrangement according to the invention shown in Fig. 2 differs from the embodiment shown in Fig. 1 primarily in that the lower end of the hood 5 is closed by a wall 20 in which several, to the axis 3, for example, substantially parallel to each other aligned, bores 21, which are arranged distributed over the surface of the wall 20, are provided.

Furthermore, in the embodiment shown in Fig. 2, the support tube 9 for the hood 5 is extended to the wall 20 and the lines 10 and 11 open out on the side of the wall 20 facing the object 4 or the carrier 1, so that treatment fluids in Exit near the disk-shaped object 4 (silicon wafer) and be applied centrally to this.

A line 22 is connected to the side wall of the hood 5 through which nitrogen or another inert gas can be introduced into the space 12 within the hood 5. The gas introduced into the space 12 exits evenly over the entire surface of the object 4 through the openings 21 and causes air to be displaced from the space between the wall 20 and the object 4, so that there is an inert gas atmosphere.

In both embodiments of the arrangement according to the invention, the hood 5 stands still and only the carrier 1 rotates with the object 4 held on it.

In order to facilitate the placing of wafers 4 on the carrier 1 and the removal of the wafers 4 from the carrier 1, the hood 5 can be moved away from its effective position approximated to the carrier 1 (FIGS. 1 and 2).

In summary, a preferred exemplary embodiment of the arrangement according to the invention for treating disc-shaped objects, in particular silicon wafers, can be described as follows:

In an arrangement for treating silicon wafers 4, a carrier 1 is for treating the

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Silicon wafer 4 is provided, which can be set in rotation about its axis 3 via a shaft 2. A hood 5, which does not rotate with the carrier 1 when a disk-shaped wafer 4 is being treated, is arranged over the surface of the carrier 1 that carries the silicon wafer 4. An inert gas, primarily nitrogen, is introduced into the interior of the hood 12 so that the air is displaced from the space 12 enclosed by the hood 5. This prevents the formation of stains due to oxidation of the silicon that makes up the wafer in the presence of water and oxygen.