Apparatus for treating surfaces of wafer-shaped articles

A device for processing wafer-shaped articles comprises a closed process chamber. The closed process chamber comprises a housing providing a gas-tight enclosure, a rotary chuck located within the closed process chamber and adapted to hold a wafer shaped article thereon, and an interior cover disposed within said closed process chamber. The interior cover is movable between a first position in which the rotary chuck communicates with an outer wall of the closed process chamber, and a second position in which the interior cover seals against an inner surface of the closed process chamber adjacent the rotary chuck to define a gas-tight inner process chamber.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates generally to an apparatus for treating surfaces of wafer-shaped articles, such as semiconductor wafers, wherein one or more treatment fluids may be recovered from within a closed process chamber.

2. Description of Related Art

Semiconductor wafers are subjected to various surface treatment processes such as etching, cleaning, polishing and material deposition. To accommodate such processes, a single wafer may be supported in relation to one or more treatment fluid nozzles by a chuck associated with a rotatable carrier, as is described for example in U.S. Pat. Nos. 4,903,717 and 5,513,668.

Alternatively, a chuck in the form of a ring rotor adapted to support a wafer may be located within a closed process chamber and driven without physical contact through an active magnetic bearing, as is described for example in International Publication No. WO 2007/101764 and U.S. Pat. No. 6,485,531. Treatment fluids which are driven outwardly from the edge of a rotating wafer due to centrifugal action are delivered to a common drain for disposal.

Although conventional closed process chambers adequately contain the hazardous substances used for wafer processing while the chamber is closed, they must be opened for loading and unloading of wafers. This causes a significant risk that process gas, chemical fumes, hot vapor such as vaporized isopropyl alcohol, ozone and the like could be released to the tool environment, which could result in significant safety risks and damage to surrounding components and tools.

SUMMARY OF THE INVENTION

The present inventors have developed an improved closed process chamber for treating wafer-shaped articles, in which an inner chamber is provided within an outer chamber, with each of the inner and outer chambers being configured to provide a gas-tight enclosure.

Thus, the invention in one aspect relates to a device for processing wafer-shaped articles, comprising a closed process chamber. The closed process chamber comprises a housing providing a gas-tight enclosure, a rotary chuck located within the closed process chamber and adapted to hold a wafer shaped article thereon, and an interior cover disposed within said closed process chamber. The interior cover is movable between a first position in which the rotary chuck communicates with an outer wall of the closed process chamber, and a second position in which the interior cover seals against an inner surface of the closed process chamber adjacent the rotary chuck to define a gas-tight inner process chamber. Preferably said movement between the first position and the second position is an axial movement along the rotational axis of rotary chuck.

In preferred embodiments of the device according to the present invention, the interior cover forms a lower portion of the inner process chamber when in the second position.

In preferred embodiments of the device according to the present invention, the interior cover comprises a base and at least one upstanding wall, the base being connected to a shaft that penetrates the closed process chamber via a seal that permits relative movement between the shaft and the closed process chamber while maintaining gas tightness of the outer process chamber. Preferably said relative movement is an axial movement along the rotational axis of rotary chuck.

In preferred embodiments of the device according to the present invention, at least one process fluid collector is formed in a lower portion of the interior cover, the process fluid collector communicating with a discharge pipe depending from the interior cover that penetrates the closed process chamber via a seal that permits relative movement between the discharge pipe and the closed process chamber while maintaining gas tightness of the outer process chamber.

In preferred embodiments of the device according to the present invention, the closed process chamber comprises independently controlled exhaust ports, a first exhaust port opening into the closed process chamber in a region inside the inner chamber when the interior cover is in the second position, and a second exhaust port opening into the closed process chamber in a region outside the inner chamber when the interior cover is in the second position.

In preferred embodiments of the device according to the present invention, the interior cover comprises a plurality of splash guards that are independently axially displaceable relative to the interior cover, the splash guards and the interior cover being adapted to define a plurality of distinct processing regions within the inner chamber when the interior cover is in the second position.

In preferred embodiments of the device according to the present invention, each of the distinct processing regions comprises a respective liquid discharge pipe in fluid communication therewith.

In preferred embodiments of the device according to the present invention, each axially displaceable splash guard is selectively driven from outside the closed process chamber to a predefined vertical position.

In preferred embodiments of the device according to the present invention, each axially displaceable splash guard is selectively positionable so as to capture a preselected process fluid emanating from a spinning wafer carried by the rotary chuck.

In preferred embodiments of the device according to the present invention, the rotary chuck is adapted to be driven without physical contact through a magnetic bearing, and the rotary chuck and the interior cover are vertically movable relative to each other.

In preferred embodiments of the device according to the present invention, the magnetic bearing comprises a stator located outside the closed process chamber.

In preferred embodiments of the device according to the present invention, the magnetic bearing is selectively positionable such that a preselected process fluid emanating from a spinning wafer carried by the rotary chuck is directed to a preselected fluid collector.

In preferred embodiments of the device according to the present invention, the magnetic bearing is an active magnetic bearing.

In preferred embodiments of the device according to the present invention, the closed process chamber is a module in a station for single wafer wet processing of semiconductor wafers.

In preferred embodiments of the device according to the present invention, the closed process chamber is made of aluminum coated with perfluoroalkoxy resin.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring now toFIG. 1, an apparatus for treating surfaces of wafer-shaped articles according to a first embodiment of the invention comprises an outer process chamber1, which is preferably made of aluminum coated with PFA (perfluoroalkoxy) resin. The chamber in this embodiment has a main cylindrical wall10, a lower part12and an upper part15. From upper part15there extends a narrower cylindrical wall34, which is closed by a lid36.

A rotary chuck30is disposed in the upper part of chamber1, and surrounded by the cylindrical wall34. Rotary chuck30rotatably supports a wafer W during used of the apparatus. The rotary chuck30incorporates a rotary drive comprising ring gear38, which engages and drives a plurality of eccentrically movable gripping members for selectively contacting and releasing the peripheral edge of a wafer W.

In this embodiment, the rotary chuck30is a ring rotor provided adjacent to the interior surface of the cylindrical wall34. A stator32is provided opposite the ring rotor adjacent the outer surface of the cylindrical wall34. The rotor30and stator34serve as a motor by which the ring rotor30(and thereby a supported wafer W) may be rotated through an active magnetic bearing. For example, the stator34can comprise a plurality of electromagnetic coils or windings that may be actively controlled to rotatably drive the rotary chuck30through corresponding permanent magnets provided on the rotor. Axial and radial bearing of the rotary chuck30may be accomplished also by active control of the stator or by permanent magnets. Thus, the rotary chuck30may be levitated and rotatably driven free from mechanical contact. Alternatively, the rotor may be held by a passive bearing where the magnets of the rotor are held by corresponding high-temperature-superconducting magnets (HTS-magnets) that are circumferentially arranged on an outer rotor outside the chamber. With this alternative embodiment each magnet of the ring rotor is pinned to its corresponding HTS-magnet of the outer rotor. Therefore the inner rotor makes the same movement as the outer rotor without being physically connected.

The lid36has a manifold42mounted on its exterior, which supplies a medium inlet44that traverses the lid36and opens into the chamber above the wafer W. It will be noted that the wafer W in this embodiment hangs downwardly from the rotary chuck30, supported by the gripping members40, such that fluids supplied through inlet44would impinge upon the upwardly facing surface of the wafer W.

In case wafer30is a semiconductor wafer, for example of 300 mm or 450 mm diameter, the upwardly facing side of wafer W could be either the device side or the obverse side of the wafer W, which is determined by how the wafer is positioned on the rotary chuck30, which in turn is dictated by the particular process being performed within the chamber1.

The apparatus ofFIG. 1further comprises an interior cover2, which is movable relative to the process chamber1. Interior cover2is shown inFIG. 1in its first, or open, position, in which the rotary chuck30is in communication with the outer cylindrical wall10of chamber1. Cover2in this embodiment is generally cup-shaped, comprising a base20surrounded by an upstanding cylindrical wall21. Cover2furthermore comprises a hollow shaft22supporting the base20, and traversing the lower wall14of the chamber1.

Hollow shaft22is surrounded by a boss12formed in the main chamber1, and these elements are connected via a dynamic seal that permits the hollow shaft22to be displaced relative to the boss12while maintaining a gas-tight seal with the chamber1.

At the top of cylindrical wall21there is attached an annular deflector member24, which carries on its upwardly-facing surface a gasket26. Cover2preferably comprises a fluid medium inlet28traversing the base20, so that process fluids and rinsing liquid may be introduced into the chamber onto the downwardly facing surface of wafer W.

Cover2furthermore includes a process liquid discharge opening23, which opens into a discharge pipe25. Whereas pipe25is rigidly mounted to base20of cover2, it traverses the bottom wall14of chamber1via a dynamic seal17so that the pipe may slide axially relative to the bottom wall14while maintaining a gas-tight seal.

An exhaust opening16traverses the wall10of chamber1, whereas a separate exhaust opening46traverses the lid36near the inner surface of rotary chuck30. Each exhaust opening is connected to suitable exhaust conduits (not shown), which are preferably independently controlled via respective valves and venting devices.

The position depicted inFIG. 1corresponds to loading or unloading of a wafer W. In particular, a wafer W can be loaded onto the rotary chuck30either through the lid36, or, more preferably, through a side door (not shown) in the chamber wall10. However, when the lid36is in position and when any side door has been closed, the chamber1is gas-tight and able to maintain a defined internal pressure.

InFIG. 2, the interior cover2has been moved to its second, or closed, position, which corresponds to processing of a wafer W. That is, after a wafer W is loaded onto rotary chuck30, the cover2is moved upwardly relative to chamber1, by a suitable motor (not shown) acting upon the hollow shaft22. The upward movement of the interior cover2continues until the deflector member24comes into contact with the interior surface of the upper part15of chamber1. In particular, the gasket26carried by deflector24seals against the underside of upper part15, whereas the gasket18carried by the upper part15seals against the upper surface of deflector24.

When the interior cover2reaches its second position as depicted inFIG. 2, there is thus created a second chamber48within the closed process chamber1. Inner chamber48is moreover sealed in a gas tight manner from the remainder of the chamber1. Moreover, the chamber48is preferably separately vented from the remainder of chamber1, which is achieved in this embodiment by the provision of the exhaust port46opening into the chamber48, independently from the exhaust port16that serves the chamber1in general, and the remainder of the chamber1in theFIG. 2configuration.

During processing of a wafer, processing fluids may be directed through medium inlets44and/or28to a rotating wafer W in order to perform various processes, such as etching, cleaning, rinsing, and any other desired surface treatment of the wafer undergoing processing.

Provision of the inner chamber48within the overall process chamber1thus enhances the safety of environmentally closed chambers by permitting the gases and liquids used for wafer processing to be better isolated from the exterior environment of the process chamber, and reduces the risk of process gas, chemical fumes, hot vapor such as vaporized isopropyl alcohol, ozone and the like being released to the tool environment.

FIGS. 3-6show a second embodiment according to the present invention, in which the interior cover2is provided with a set of dividers so that separate processing regions can be defined within the inner chamber48. Specifically, within the interior cover2, one or more vertically movable splash guards37,39. InFIGS. 3-6two circular splash guards37and39are shown although it will be appreciated that any desired number of splash guards may be provided and are contemplated by this disclosure, the actual number of splash guards depending in part upon the number of different process fluids which are intended to be separately collected.

The outer splash guard37is positioned concentrically about the inner splash guard39. Thus, the inner splash guard39defines an inner process fluid collector within its interior. A middle process fluid collector is defined by an annular region formed between the outer surface of the inner splash guard39and the inner surface of the outer splash guard37. An outer process fluid collector is defined by an annular region formed between the outer surface of the outer splash guard37and the inner surface of the cylindrical wall21.

Associated with each such fluid collector a drain is provided for delivering collected process media from the respective fluid collector to outside the closed process chamber. As shown inFIG. 3, drains31,33and35each extend through the base20of the interior cover, and also through the bottom wall14of the main chamber1. The assembly of drains31,33and35is associated with bottom wall14via a dynamic seal as described above, to permit relative movement of the drain lines and the outer chamber1while the interior cover2is moved, while maintaining a gas-tight seal.

Deflector27in this embodiment is somewhat elongated to accommodate the upper portions of splash guards37and39, but is otherwise as described above in connection with the first embodiment.

Splash guards37and39are moved up and down relative to interior cover2by suitable actuators such as pneumatic cylinders, combinations of pneumatic and hydraulic cylinders, linear motors, Bowden wires or the like. Although not shown in the accompanying drawings, the actuators for splash guards37and39are similarly mounted traversing bottom wall14via a dynamic seal.

Each splash guard is independently movable in the vertical direction. Accordingly, each splash guard can selectively be raised and/or lowered relative to the rotary chuck30, relative to any other splash guard, and relative to the interior cover2, such that excess process fluid emanating from the trailing edge of the rotary chuck30is directed toward a selected fluid collector.

InFIGS. 3 and 4, both splash guards37and39are shown in an elevated status, such that, in the working position depicted inFIG. 4, excess process fluid emanating from the trailing edge of the rotary chuck30is directed against the inner surface of the inner splash guard39and into the inner fluid collector31. Thus, excess fluid from the surface of a wafer undergoing processing can be selectively recovered through drain31and optionally recycled or reused.

InFIG. 5, both splash guards37and39are in their upper lower relative to interior cover2, with interior cover2being in its second or closed position. In this configuration, excess process fluid emanating from the trailing edge of the rotary chuck30is directed against the inner surface of the cylindrical wall21and into the outer fluid collector35. Thus, excess fluid from the surface of a wafer undergoing processing can be selectively recovered through drain35and optionally recycled or reused.

InFIG. 6, splash guard39is in its lower position while splash guard37is in its upper position relative to interior cover2, with interior cover2being in its second or closed position. In this configuration, excess process fluid emanating from the trailing edge of the rotary chuck30is directed against the inner surface of the outer splash guard37and into the middle fluid collector33. Thus, excess fluid from the surface of a wafer undergoing processing can be selectively recovered through drain33and optionally recycled or reused.

FIGS. 7 and 8show a third embodiment of the present invention, in which the chamber design of the first embodiment is adapted for use with a spin chuck in which a wafer W is mounted on an upper side of a chuck that is rotated through the action of a motor on a central shaft.

In particular, wafer W is loaded onto spin chuck50when interior cover2is in the loading/unloading position depicted inFIG. 7, and wafer W is secured in the predetermined orientation relative to chuck50by gripping members40. Interior cover2is then moved to its second position, as described above in connection with the first embodiment, to define the inner chamber48.

In this embodiment, it will be seen that spin chuck50is also vertically moveable relative to the interior cover2, so that it can be raised to an optimum processing position within the chamber48. Spin chuck50is then rotated by a motor (not shown) acting upon shaft55.

FIGS. 9 and 10show a fourth embodiment of the present invention, in which the spin chuck50of the preceding embodiment rotates relative to interior cover2, but does not move axially relative to the interior cover2.

Thus, wafer W is loaded onto spin chuck50with interior cover2is in the loading/unloading position depicted inFIG. 9, and wafer W is secured in the predetermined orientation relative to chuck50by gripping members40. Interior cover2is then moved to its second position as depicted inFIG. 10and as described above in connection with the first embodiment, to define the inner chamber48.

As the spin chuck50of this embodiment is not vertically moveable relative to the interior cover2, the movement of the interior cover2serves simultaneously to position wafer W at its final processing position within the chamber48. Spin chuck50is then rotated by a motor (not shown) acting upon shaft55.