Device for decontaminating a semiconductor wafer container

Claims

What is claimed is:

1. A decontamination device for a wafer container having a chamber for storing semiconductor wafers and inner surfaces surrounding said chamber, said container having movable portions manipulatable between a container open condition and a container closed condition, said device comprising:

a support/containment assembly having a substantially sealed containment compartment and a support element which at least initially provides a support for said wafer container;

a manipulating assembly, movably mounted in said support/containment assembly, and provided with a manipulator which manipulates said wafer container between said open condition and said closed condition and which places said chamber, when such wafer container is in said open condition, in a position whereat it forms a portion of said containment compartment and is in flow communicating what said containment compartment; and

a gas flow assembly, mounted on said support/containment assembly, which supplies a substantially continuous flow of circulation gas throughout said containment compartment and throughout said container chamber when it is in flow communication with said containment compartment, a manifold within said containment compartment movable with respect to said containment compartment which dispenses blow-off gas provided from said gas flow assembly, said manifold being sized to fit within said chamber of said wafer container;

said manipulating assembly also positions said manifold within said chamber and in close proximity to said inner surfaces whereby said blow-off gas contacts said inner surfaces and whereby particles adhered to said surfaces will be released and entrained by said continuous flow of circulating gas.

2. A decontamination device as set forth in claim 1 wherein said gas flow assembly includes an ionization element which periodically ionizes the gas flows through said containment compartment whereby statically charged containment particles adhered to said inner surfaces of said wafer container will be released and entrained by said flow of circulation gas.

3. A decontamination device as set forth in claim 1 wherein said gas flow assembly further includes:

a blower which induces the circulation gas to circulate through said containment compartment;

a filter, sealably connected to the outlet of said blower, which filters said circulation gas thereby creating a flow of filtered circulation gas;

a circulation gas supply which supplies said filtered circulation gas to said manifold; and

a blow-off gas supply which supplies said blow-off gas to said manifold.

4. A decontamination device as set forth in claim 1 wherein said manipulating assembly comprises a first manipulating assembly including:

a container-manipulating mechanism which manipulates said wafer container; and

a manifold-manipulating mechanism which positions said manifold within such chamber and in close proximity to said inner surfaces.

5. A decontamination device for a wafer container having a chamber for storing semiconductor wafers and inner surfaces surrounding said chamber, said container having movable portions manipulatable between a container open condition and a container closed condition, said device comprising:

a support/containment assembly having a substantially sealed containment compartment and a support element which at least initially provides a support for said wafer container;

a manipulating assembly, movably mounted in said support/containment assembly, and provided with a manipulator which manipulates such wafer container between said open condition and said closed condition and which places said chamber, when said wafer container is in said open condition, in a position whereat it forms an extension of id containment compartment nd is in communication with said containment compartment; and

a gas flow assembly, mounted on said support/containment assembly, which supplies a substantially continuous flow of circulation gas throughout said containment compartment and throughout said container chamber when it is in flow communication with said containment compartment, a manifold within said containment compartment movable with respect to said containment compartment which dispenses said circulation gas and blow off gas provided from said gas flow assembly, said manifold comprising a main body and a bottom extension, said main body being sized to fit within said chamber of said wafer container;

said manipulating assembly also positions said main body portion of said manifold within said chamber and in close proximity to said inner surfaces whereby said blow-off gas contacts said inner surfaces and whereby particles adhered to said surfaces will be released and entrained by said continuous flow of circulation gas; and

wherein said gas flow assembly further includes a blower which induces said circulation gas to circulate through said containment compartment, a filter which is sealably connected to the outlet of said blower and which filters said circulation gas thereby creating a flow of filtered circulation gas, a circulation gas supply which supplies said filtered circulation gas to said manifold; and a blow-off gas supply which supplies said blow-off gas to said manifold.

6. A decontamination device for a wafer container having a chamber for storing semiconductor wafers and inner surfaces surrounding said chamber, said container having movable portions manipulatable between a container open condition and a container closed condition, said device comprising:

a support/containment assembly having a substantially sealed containment compartment and a support element which at least initially provides a support for said wafer container;

a manipulating assembly, movable mounted in said support/containment assembly, and provided with a manipulator which manipulates said wager container between said open condition and said closed condition and which places said chamber, when such wafer container is in said open condition, in a position whereat it forms an extension of said containment compartment nd is in flow communication with said containment compartment; and

a gas flow assembly, mounted on said support/containment assembly, which supplies a substantially continuous flow of circulation gas throughout said containment compartment and throughout said container chamber when it is in flow communication with said containment compartment, a manifold within said containment compartment movable with respect to said containment compartment which dispenses said circulation gas and glow off gas provided from said gas flow assembly, said manifold comprising a main body and a bottom extension, said main body being sized to fit within said chamber of said wafer container;

said manipulating assembly also position said main body portion of said manifold within said chamber and in close proximity to said inner surfaces whereby said blow-off gas contacts said inner surfaces and whereby particles adhered to said surfaces will be released and entrained by said continuous flow of circulation gas; and

wherein said gas flow assembly further includes a blower which induces said circulation gas to circulate through said containment compartment, a filer which is sealably connected to the outlet of said blower and which filers said circulation gas thereby creating a flow of filtered circulation gas, a circulation gas supply which supplies said filtered circulation gas to said manifold; and a blow-off gas supply which supplies said blow-off gas to said manifold; and

wherein said manifold further comprises a circulation gas dispenser located on said main body, a top blow-off gas dispenser located on a top portion of said main body, a side blow-off gas dispenser located on said portions of said main body, a bottom blow-off gas dispenser located on said bottom extension a top ionization element located within said main body, and a bottom ionization element located within in said bottom extension.

7. A decontamination device for a wafer container having a chamber for storing semiconductor wafers and inner surfaces surrounding said chamber, said container having movable portions manipulatable between a container open condition and a container closed condition, said device comprising:

a support/containment assembly having a substantially sealed containment compartment and a support element which at least initially provides a support for said wafer container;

a manipulating assembly, movably mounted in said support/containment assembly, which manipulates said wafer container between said open condition and said closed condition and which places said chamber, when said wafer container is in said open condition, in a position whereat it forms an extension of said containment compartment and is in flow communication with said containment compartment; and

a gas flow assembly, mounted on said support/containment assembly, which supplies a substantially continuous flow of circulation gas throughout said containment compartment and throughout said container chamber when it is in flow communication with said containment compartment, a manifold within said containment compartment movable with respect to said containment compartment for dispensing blow-off gas provided from said gas flow assembly, said manifold being sized to fit within such chamber of such wafer container;

said manipulating assembly also positions said manifold within said chamber and in close proximity to said inner surfaces whereby said blow-off gas contacts said inner surfaces and whereby particles adhered to said surfaces will be released and entrained by said continuous flow of circulating gas;

wherein said manipulating assembly comprises a first manipulating assembly including a container-manipulating mechanism which manipulates said wafer container, and a manifold-manipulating mechanism which positions said manifold within said chamber and in close proximity to said inner surfaces; and

wherein said manipulating assembly further comprises a second manipulating assembly which mounts said manifold on said first manipulating assembly.

8. A decontamination device as set forth in claim 7 wherein said support/containment assembly supports the portions of said wafer container forming such chamber in a substantially stationary manner and wherein said manifold-manipulating mechanism includes an elevator which vertically moves said manifold past said inner surfaces of said chamber.

9. A decontamination device as set forth in claim 8 wherein said second manipulating assembly includes a loading mechanism which moves said manifold from a rest position horizontally offset from said elevator to a transfer position vertically aligned with said elevator.

10. A decontamination device as set forth in claim 9 wherein said loading mechanism includes a cylinder-position unit having a piston and a load arm having a first end and an opposite end, said load arm including a holding device for said manifold at said first end and said load arm being operatively connected to the piston of said cylinder-piston unit at the opposite end whereby when said piston is retracted said manifold is placed in said rest position and when piston is extended said manifold is placed in said transfer position.

11. A decontamination device as set forth in claim 10 wherein said elevator includes a horizontal platform which holds said manifold and wherein said elevator moves said horizontal platform between:

a manifold-loading level whereat said manifold is positioned slightly above, and vertically aligned with, said horizontal platform;

a manifold-unloading level whereat said manifold may be positioned horizontally aligned with said load arm;

an upper blow-off level whereat said manifold may be positioned within such chamber of such container; and

a container-manipulating level whereat said first manipulating assembly is positioned to manipulate such container.

12. A decontamination device for a wafer container having a chamber for storing semiconductor wafers and inner surfaces surrounding said chamber, said container having a top portion and a removable bottom portion and being manipulable between a container open condition by removing the bottom portion whereby the portions are detached from each other and a container closed condition whereat said portions are connected to each other, said device comprising:

a support/containment assembly having a substantially sealed containment compartment and a support element which at least initially provides a support for said wafer container;

a manipulating assembly movably mounted in said support/containment assembly and provided with a manipulator for manipulating said wafer container sin such a manner that said top portion is detached from said bottom portion and said chamber is placed in a position whereat it forms an extension of said containment compartment and is in flow communication with said containment compartment; and

a gas flow assembly, mounted on said support/containment assembly, for supplying a substantially continuous flow of circulating gas throughout said containment compartment ad throughout said container chamber when it is in flow communication with said containment compartment, a movable manifold within said containment compartment which dispenses blow-off gas provided from said gas flow assembly, said manifold being sized to fit within said chamber of said wafer container;

said manipulating assembly also positions said manifold within said chamber and in close proximity to said inner surfaces whereby said blow-off gas contacts said inner surfaces and whereby particles adhered to said surfaces will be released and entrained by said continuous flow of circulation gas.

13. A method of using the decontamination device set forth in claim 3 to decontaminate a wafer container having a chamber for storing semiconductor wafers and inner surfaces surrounding said chamber, said container being manipulatable between a container open condition and a container closed condition, said method comprising the steps of:

providing a substantial sealed containment compartment;

continuously supplying and filtering a flow of circulation gas throughout the containment compartment;

manipulating the wafer container between said closed condition and said open condition and placing the chamber, when said wafer container is in said open condition, in a position whereat it forms an extension of said sealed containment compartment and is in communication with the sealed containment compartment whereby the circulation gas flows throughout the chamber;

connecting a manifold to a supply of blow-off gas;

inserting the manifold within the chamber of the wafer container; and

periodically supplying a flow of blow-off gas and directing the blow-off gas toward the inner surfaces of the wafer container whereby the blow-off gas will contact the inner surfaces and whereby particles adhered to said surfaces will be released and entrained by the continuous flow of circulation gas.

14. A decontamination device for a wafer container having a chamber for storing semiconductor wafers and inner surfaces surrounding such chamber, such container including a top portion and a bottom portion, the container being placed in an open condition when the portions are connected to each other and being placed in a closed condition when id portions are detached from each other, said device comprising:

a support/containment assembly which provided a substantially sealed containment compartment nd which at least initially provides a support for such wafer container;

a manipulating assembly, mounted on said support/containment assembly, which manipulates such wafer container whereby such top portion is detached from such bottom portion and such chamber is placed in communication with said containment compartment; and

a gas flow assembly, mounted on said support/containment assembly, which supplies a substantially continuous flow of circulation gas throughout said containment compartment nd throughout such chamber when in communication with said containment compartment and which periodically supplies a flow of blow-off gas;

wherein said manipulating assembly also positions said gas flow assembly within such chamber and in close proximity to such inner surfaces.

FIELD OF THE INVENTION

This invention relates generally as indicated to a device and method for decontaminating a wafer container which is used in a semiconductor device fabrication system. More particularly, the present invention elates to a device/method for removing airborne contamination particles in the container by providing a continuously filtered circulation gas flow. Additionally, the device/method releases charted or otherwise adhered contamination particles form the inner surfaces of the container whereby they may be entrained by the continuously filtered circulation gas and subsequently removed.

BACKGROUND OF THE INVENTION

Semiconductor device are commonly manufactured in a semiconductor fabrication process nd the earlier stages of this process involve semiconductor "wafers." In a typical fabrication process, a plurality of these wafers are loaded in a carrier, or container, for transportation to and form the appropriate wafer-processing stations. In some fabrication systems, the container designed to directly hold the wafers by providing, for instance, the container with wafer-receiving ridges or grooves. In other systems, the container is designed to hold a "cassette" in which the wafers have previously been stacked. However, while a carrier may be of many designs, almost all carriers may be viewed as having chamber for storing the wafers and as having inner surfaces surrounding this chamber.

At some wafer-processing stations, the wafers are almost immediately unloaded, subjected to the appropriate fabrication procedure, and then re-loaded into the carrier for conveyance to a subsequent station. In other cases, the wafer-loaded carrier is stored temporarily in, for example, a closed clean box at the relevant wafer-processing site in anticipation of the next semiconductor fabrication step. In still other wafer-processing stations, such as water rinsing and wet chemical etching, the wafers are processed without being unloaded from the carrier.

A key enemy in almost any semiconductor fabrication process is "particulate contamination" which is the impurity caused by particles and chemicals contained in the fabricating environment. Such contamination is known to be directly responsible for decreased reliability in the fabricated semiconductor devices. While particulate contamination has always been a potential problem, its harmful impact proceeds to increase as the circuit pattern sizes of semiconductor devices continue to decrease to sub-micron dimensions.

Accordingly, particulate contamination control is essential to the success of a semiconductor device fabrication process. As such, diligent attempts are made to insure minimal particulate contamination in the surrounding "fabrication environment." An important part of this fabrication environment is the wafer carrier, or container, because the semiconductor wafers are actually exposed to the air within the chamber and they are in such close proximity to the inner surface. Because of the essentially continual use of such carriers in the fabrication process, airborne particulate tend to accumulate within the carrier chamber. Additionally, certain fabrication treatments tend to encourage contamination particulate to statically or otherwise adhere to the inner surfaces of the carrier surrounding the chamber. This contamination of the carrier chamber and inner surfaces seems to inevitably occur even in fabrication environments where particulate contamination is kept to an absolute minimum.

As such it would be desirable to periodically withdraw a carrier from the fabrication process and thoroughly decontaminate its chamber and inner surface. Such a decontamination operation would preferably include the removal of airborne contamination particles in the carrier chamber. Additionally, to be fully effective, the decontamination operation would also need to include the steps of releasing, and subsequently removing, contamination particles statically or otherwise adhered to the inner surfaces of the carrier surrounding the chamber.

SUMMARY OF THE INVENTION

The present invention provides a decontamination device for a wafer container having a chamber for storing semiconductor wafers and inner surfaces surrounding such chamber. The device includes a support/containment assembly for providing a substantially sealed containment compartment and a gas flow assembly, for supplying and filtering a substantially continuous flow of circulation gas throughout the containment compartment. Additionally, the gas flow assembly periodically directs a flow of blow-off gas towards the inner surfaces of the wafer container whereby particles adhered to such surfaces will be released and entrained by the continuous flow of circulation gas. The decontamination device may include ionization components, mounted on the gas flow assembly, for periodically ionizing the gas flow through the containment compartment whereby charged containment particles adhered to the inner surfaces of the wafer container will be released and entrained by the circulation gas. Manipulating assemblies, also mounted on the support/containment assembly, manipulate the wafer container whereby the chamber is in communication with the containment compartment. These manipulating assemblies also position the gas flow assembly within the chamber and in close proximity to the inner surfaces whereby the blow-off gas will be properly directed.

The present invention also provides a method of decontaminating a wafer container having a chamber for storing semiconductor wafers and inner surfaces surrounding this chamber. The method includes providing a substantially sealed containment compartment and continuously supplying and filtering a flow of circulation gas throughout the containment compartment. The wafer container is then manipulated so that its chamber is in communication with the sealed containment chamber. A flow of blow-off gas is periodically directed towards the inner surfaces of the wafer container. The method may also include the step of periodically ionizing the circulation gas and blow-off gas whereby statically charged containment particles will be released and entrained by the circulation gas.

These and other features of the invention are fully described and particularly pointed out in the claims. The following descriptive annexed drawings set forth in detail one illustrative embodiment, however this embodiment is indicative of but one of the various ways in which the principles of the invention may be employed.

BRIEF DESCRIPTION OF THE DRAWINGS

In the annexed drawings:

FIG. 1 is a front view of a decontamination device according to the present invention;

FIG. 2 is a top view of the decontamination device as seen from line 2--2 in FIG. 1;

FIG. 3 is a side view of a gas flow assembly which is removably mounted to a second manipulating assembly, these components being shown isolated from the rest of the device;

FIG. 4 is a schematic diagram of the flow patterns through the gas flow assembly of the decontamination device;

FIG. 5 is a side view of a first manipulating assembly of the device of FIGS. 1 and 2, this assembly being shown isolated from the rest of the device; and

FIG. 6A-6G are side views of the gas flow assembly, the first manipulating assembly and the second manipulating assembly, these components being shown isolated from the rest of the device and in various stages of the decontamination process.

DETAILED DESCRIPTION

Turning now to the drawings in detail and initially to FIG. 1, a decontamination device 10 for a wafer container 12 is shown. In a typical fabrication process, a plurality of wafers (not shown) would be loaded into this container 12 for transportation to and from the appropriate wafer-processing stations. The container 12, like most carriers of this type, may be viewed as having an inner chamber 14 for storing the wafers and inner surfaces 16 and 18 surrounding the chamber 14. Additionally, the container 12 includes a top portion 20 and a bottom portion 22 detachably connected to the top portion, although these features may be particular to the illustrated design of the carrier.

The decontamination device 10 of the present invention is designed to provide periodic decontamination for carriers such as the wafer container 12. Thus, while the device 10 would not be directly involved in a semiconductor fabrication process, it would play an important role in the success of such a process by insuring minimal particulate contamination in the wafer container 12. More specifically, the decontamination device 10 removes airborne contamination particles in the container chamber 14 and releases, and subsequently removes, contamination particles statically or otherwise adhered to the inner surfaces 16 and 18 of the container 12.

The decontamination device 10 includes a support/containment assembly 30 which supports the other components of the device while at the same time provides a substantially sealed containment compartment 32. The support elements of the assembly 30 may be designed in any manner which is compatible with the other components of the device 10 and which accommodates the container 12. More particularly, the support/contamination assembly 30 is adapted so that the container 12 may be sealably mounted thereto, and during the intermediate stages of the decontamination process, the container chamber 14 will be in communication with, or form an extension of, the containment compartment 32.

The actual "decontamination" process, which takes place within the containment compartment 32, is performed by a gas flow assembly 34. As is explained in more detail below, the gas flow assembly 34 continuously circulates, and filters, a low velocity circulation gas within the containment compartment 32 and the container chamber 14. In this manner, any airborne contamination particles in the circulation gas are removed whereby the gas within the containment compartment 32 is constantly purified.

In addition to this circulation gas flow, the gas flow assembly 34 periodically directs a flow of high velocity compressed "blow-off" gas towards the inner surfaces 16 and 18 of the container 12 thereby encouraging the release any adhered particles therefrom. Still further, the gas flow assembly 34, at appropriate points in the decontamination cycle, ionizes either the circulation gas and/or the blow-off gas thereby persuading the release of any statically charged particles clinging to the inner surfaces 16 and 18 of the container 12. The released particles are then entrained by the circulation gas and, because this circulation gas is constantly being filtered, the released contamination particles are eventually removed.

The decontamination device 10 further includes a first manipulating assembly 36 and a second manipulating assembly 38 which manipulate the container 12 and the gas flow assembly 34 so that the decontamination process may be effectively performed. Although manual control of some or all of the various components of the decontamination device 10 is possible, automatic operation is preferred. To this end, the gas flow assembly 34 and the manipulating assemblies 36 and 38 are electrically powered, the power being supplied to the device 10 when a switch (not shown) is manually placed in an "on" position. Additionally, the device includes a programmable controller 40 which automatically coordinates the operation of the gas flow assembly 34 and the manipulating assemblies 36 and 38.

Perhaps the best way to explain the interaction of the components of the decontamination device 10, and their coordination via the programmable controller 40, is to briefly outline a typical decontamination cycle. Before beginning of a decontamination cycle, the power switch is then turned on, thereby supplying electric power to the various components of the decontamination device 10. Once the power is turned on, the gas flow assembly 34 continuously circulates, and filters, a circulation gas within the containment compartment 32. Additionally, the programmable controller 40 is energized whereby it may automatically control the operation of the device.

To begin a cycle of the decontamination process, a container, such as the container 12, is mounted in the appropriate position on top of the support/containment assembly 30. A start button (not shown) is then depressed to further activate the decontamination device 10 to perform the next stages of the decontamination process. The depression of this button results in the first manipulating assembly 36 uncoupling, and separating, the top portion 20 and the bottom portion 22 of the wafer container 12. The support/containment assembly 30 is designed so that such uncoupling and separating results in the container chamber 14 being in communi