JP2525284C - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a clean transfer method capable of transferring conveyed objects required for processing and assembling of semiconductor-related products and the like in a clean state free of pollutants. Related to the device. (Summary of the Invention) The present invention relates to a clean transfer method and apparatus for transferring a transferred object necessary for processing and assembling of a semiconductor-related product or the like, using a movable vacuum clean box having a vacuum degree of 1 Torr or less. Can be transported in a clean state free of pollutants such as dust. (Prior Art) FIGS. 7 and 8 show a conventional clean transfer method. In these figures, a room 1 is divided into a maintenance room 3 and a clean room 4 by a partition wall 2. The maintenance room 3 is open to the atmosphere, and various devices 5 used for a precision film forming process required for semiconductor manufacturing are arranged. On the other hand, the clean room 4 has a class 100 to 10 (however, the class 100 has a cleanness of less than 100 dust of 0.5 μm or less in a 1-foot cube, and the class 10 has a cleanness of 10 or less similarly. Say)) is kept at a fairly good degree of cleanliness. An air flow is blown down from the ceiling of the clean room 4 through a filter F corresponding to a class 100 to 10 and exhausted from a floor surface 7 in a grating state (perforated state). Then, in the clean room 4, the classes 10-1
(However, class 1 means cleanliness of less than 0.5 μm dust in one foot cube.) Clean shuttle 6 with extremely good cleanliness
Are movably arranged. The transfer ports of the various devices 5 are opened in the wall surface of the partition wall 2 on the clean room side, and the peripheral portion P of the opening is locally maintained in a class 10 to 1 clean degree. As shown in FIG. 2, the transfer of the transferred object W such as a semiconductor wafer between the clean shuttle 6 and the apparatus 5 is performed by locally transferring the transferred object W from the clean shuttle 6 to the class 10 near the apparatus transfer port. Through the opening peripheral portion P, which is set to 1, the device enters the load lock chamber (sub-vacuum chamber) 8 of the device 5, closes the shutter at the transfer port on the device side, evacuates the preliminary vacuum chamber, and evacuates the vacuum chamber 9 of the device 5 It is to be carried into. Another prior art is a so-called multi-chamber system shown in FIG. In this case, one load lock chamber for loading and unloading an object to be transferred such as a semiconductor wafer is installed in a device C for performing processes such as sputtering, CVD, and etching.
This is shared by H1, CH2 and CH3. (Problems to be Solved by the Invention) By the way, in the case of the conventional clean transfer method shown in FIGS. 7 and 8, a relatively wide clean room 4 of a class 100 to 10 having a very good cleanness is required.
Equipment for maintaining proper cleanliness in this large clean room is expensive. In addition, it is necessary to provide a load lock chamber 8 for receiving an object to be transported on the side of the apparatus provided with the vacuum chamber 9, so that the vacuum evacuation of the load lock chamber is indispensable, and the structure of the apparatus side is not complicated. Not get. Furthermore, even if the cleanness is improved, it is difficult to reduce the number of suspended dust to substantially zero.
When the transported object is transferred between the apparatus and the apparatus 5, there is a possibility that the transported object is contaminated with dust. In the clean transfer method called a multi-chamber system in FIG. 9,
There is a tendency that the number of devices cannot be increased, the arrangement is not flexible, and maintenance is difficult. The applicant has proposed Japanese Patent Application Laid-Open No. 63-28047, but no particular consideration has been given to the degree of vacuum of the clean chamber used here. The present inventor has experimentally found that when performing semiconductor-related operations (e.g., vapor deposition, sputtering, or ion implantation) in a vacuum, if the degree of vacuum is 1 Torr or less, dust does not float. Therefore, the present invention provides a clean transfer method and apparatus that can transfer a transferred object such as a semiconductor wafer to various apparatuses having a vacuum chamber and can be applied to a high-precision thin film forming process and the like while stably maintaining a clean environment. The purpose is to provide. (Means for Solving the Problems) In order to achieve the above object, the clean transfer method of the present invention air-tightly couples a transfer port of a movable vacuum clean box with a vacuum degree of 1 Torr or less and a transfer port of a vacuum chamber. In the case where the transferred object is transferred in a state in which the transfer is performed, shutters are respectively provided in the openings of the transfer ports of the vacuum clean box and the vacuum chamber, and the shutters are detached from the openings in a state where they are abutted with each other. The invention is characterized in that the vacuum clean box and the vacuum chamber are communicated with each other. Further, the clean transfer apparatus of the present invention includes a movable vacuum clean box having a degree of vacuum of 1 Torr or less and a vacuum chamber, the vacuum clean box and the vacuum chamber having a transfer port capable of being hermetically coupled to each other, A shutter is provided at the opening of the transfer port of the vacuum clean box and the vacuum chamber, and the shutters are separated from the opening in a state where they are airtightly abutted with each other to connect the vacuum clean box and the vacuum chamber. Configuration. (Operation) In the clean transfer method and apparatus according to the present invention, the transferred object is transferred while the transfer port of the vacuum clean box having a vacuum degree of 1 Torr or less and the transfer port of the vacuum chamber are airtightly connected to each other. Is not required to have a very good cleanliness inside the room where it moves.
000 means a cleanness of less than 10,000 dusts of 0.5 μm or less in a 1-foot cube. ) A simple clean room is sufficient. Compared with the case where a conventional high-class clean room is provided, a grating-like floor surface or the like is not required and the equipment is simple, so that the cost can be reduced. In addition, a transferred object such as a semiconductor wafer can be transferred while maintaining a clean environment stably, and the yield can be improved, and it can be used as it is in a highly accurate thin film forming process or the like. Further, as compared with the conventional multi-chamber system, there is no restriction on the number of units to be arranged or exchanged, and flexibility in small-quantity production of many kinds can be secured. (Embodiment) An embodiment of a clean transfer method and apparatus according to the present invention will be described below with reference to the drawings. 1 to 4, a room 1 is separated into a maintenance room 3 opened to the atmosphere by a partition wall 2 and a simple clean room 10 having a slightly higher degree of cleanness. In the maintenance room 3, various devices 11 used for a precision film forming process and the like necessary for semiconductor manufacturing are arranged. Various devices 11 include a vacuum chamber 13. The simple clean room 10 may have a degree of cleanliness of about 10,000 class, and need not have a grating floor or the like as shown in FIG. The transfer port 20 of the various devices 11 is disposed on the side wall surface of the partition wall 2 in the simple clean room. In this simple clean room 10, a vacuum clean box 15 mounted on a cart 12 or the like is movably arranged. That is, the simple clean room 10 is used as a transfer room for transferring the transferred object. The degree of vacuum inside the vacuum clean box 15 is set to a clean state of 1 Torr or less. Here, the vacuum clean box 15 may have its own vacuum evacuation system, or the inside of the clean box may be reduced to 1 at the start of use by vacuum evacuation means arranged elsewhere.
You may make it evacuate below Torr. As shown in FIGS. 3 and 4, a shutter 21 is airtightly fitted to a transfer port 20 with a flange of various devices 11 having a vacuum chamber 13, and a transfer port 22 of a vacuum clean box 15. Also, the shutter 23 is fitted airtightly.
That is, the shutter 21 is provided with an O-ring 32 for hermetically sealing the space between the transfer port 20, and the shutter 23 is similarly provided with an O-ring 33 for hermetically sealing the space between the transfer port 22. I have. An O-ring 25 is arranged on the abutting surface (flange surface) of the apparatus-side transfer port 20, and a lock member 26 for locking the shutter 21 is provided behind the flange of the transfer port 20. Also, O-rings 27 and 28 are arranged on the butting surfaces of the shutters 21 and 23, respectively, and permanent magnets 30 and 31 are embedded and fixed to the shutters 21 and 23 so that they can be attracted to each other. The structures of the transfer ports 20 and 22 including these shutters 21 and 23 form a double gate valve structure. Now, the reason why the degree of vacuum inside the vacuum clean box 15 is set to 1 Torr or less will be described with reference to FIGS. FIG. 5 shows that the number of floating dust particles when the experimental chamber opened to the atmosphere was sealed at time 0 minute and the inside of the experimental chamber was evacuated by the evacuation system was 10 μm, 5 μm, and 3 μm. , 1 μm, 0.5
It is counted for μm. In this figure, the inside of the experimental chamber is 20T
In the area of orr or 5 Torr to several Torr, dust floating is observed, but it is understood that the floating of each dust disappears at 1 Torr or less. Fig. 6 shows the result of counting the number of floating dust immediately after the leak or one minute after the leak at 8 Torr, 15 Torr, and 20 Torr by leaking the vacuum-sealed experimental chamber and putting a little air into the chamber. It is. FIG. 6 shows that when air enters the chamber due to a leak and becomes more than several Torr, dust floats. 5 and 6 that if the chamber has a vacuum of 1 Torr or less, there is no floating dust, but the degree of vacuum drops below 1 Torr. You can see it. The transfer of the transferred object W such as a semiconductor wafer is performed as follows. First, the inside of the vacuum clean box 15 is evacuated to a pressure of 1 Torr or less in advance, and the transported object W is removed from the vacuum clean box 15 as shown in FIG.
Is mounted on the mounting table 40 inside. Then, as shown in FIG. 4, the abutting surface of the transfer port 20 of the vacuum chamber 13 on the apparatus side is pressed against the abutting surface of the transfer port 22 on the clean box side to hermetically seal the space between the two transfer ports and the shutters 21 and 23. The butting surfaces are attracted to each other by the permanent magnets 30 and 31, the air between the shutter butting surfaces is trapped by the O-rings 27 and 28, and the shutters 21 and 23 that are integrated with the locking member 26 in the unlocked state are the first and second shutters. 4 Remove the line as shown by the imaginary line and transfer ports 20 and 2
Let 2 communicate. Then, the transferred object W on the vacuum clean box side is transferred to a predetermined position on the apparatus side, for example, on the holder 41 in the apparatus side vacuum chamber 13 and changed. The transfer of the transferred object from the inside of the apparatus to the inside of the vacuum clean box can be similarly performed in a state where the transfer ports 20, 22 are airtightly connected as shown in FIG. Since the shutters 21 and 23 are detached from each other in an airtight state, there is no air leak due to the opening and closing of the shutters. Further, the inside of the vacuum chamber 13 on the side of the various devices 11 is usually a high vacuum of 1 Torr or less, and even if the vacuum chamber 13 on the device side is communicated with the vacuum clean box 15 as shown in FIG. 1To
There is no possibility that the vacuum clean box will deteriorate, and the vacuum clean box can be continuously used for transferring the next transferred object. (Effects of the Invention) As described above, according to the present invention, it is possible to transfer an object to be transferred while the transfer port of the vacuum clean box having a vacuum degree of 1 Torr or less and the transfer port of the vacuum chamber are airtightly connected to each other. It is possible to transfer an object to be transferred such as a semiconductor wafer while stably maintaining a clean environment in which dust does not float. Therefore, the present invention can be applied to a high-precision film formation process and the like, and can sufficiently cope with future production of ultra-precision elements such as semiconductors, and can improve the production yield. Also,
The number of vacuum clean boxes and vacuum chambers can be increased / decreased or replaced as appropriate, ensuring sufficient flexibility for low-volume, high-mix low-volume production. Since the degree of cleanliness is low, the equipment is simplified. Further, since the transferred object is directly transferred from the vacuum clean box to the vacuum chamber, a load lock chamber or the like which has been conventionally required is unnecessary, and the structure of the apparatus having the vacuum chamber can be simplified. Further, since the shutters at the transfer ports of the vacuum clean box and the vacuum chamber are detached from each other in an airtight state, there is no air leak accompanying the opening and closing of the shutters.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view showing an embodiment of a clean transfer method and apparatus according to the present invention.
FIG. 3 is a side view showing the structure of the vacuum clean box and the apparatus-side transfer port, and FIG. 3 is a side sectional view showing a state before connection, and FIG. FIG. 5 is a graph showing the relationship between the number of suspended dust and the degree of vacuum in the chamber, FIG. 6 is a graph showing the number of suspended dust when air leaks into the vacuum-sealed chamber, and FIG. FIG. 8 is a plan view showing an example of the clean transfer method, FIG.
FIG. 9 is a plan view showing a conventional multi-chamber system. DESCRIPTION OF SYMBOLS 1 ... Room, 2 ... Partition wall, 3 ... Maintenance room, 10 ... Simple clean room, 11 ... Device, 1
2 ... Dolly, 15 ... Vacuum clean box, 20,22 ... Transport opening, 21,23 ... Shutter, 30,31 ... Permanent magnet, W ... Conveyed object.

Claims (1)

[Claims] (1) A clean transfer method for transferring a transferred object in a state where the transfer port of a movable vacuum cleaner box having a vacuum degree of 1 Torr or less and the transfer port of a vacuum chamber are airtightly connected to each other.
In the method, a shutter is provided at the opening of the transfer port of the vacuum clean box and the vacuum chamber.
Are provided, and their shutters are airtightly butted against each other.
A clean transfer method, wherein the vacuum transfer box is communicated with the vacuum chamber outside the opening . (2) Place the device having the vacuum chamber in a maintenance room opened to the atmosphere, and place the vacuum clean box in a transfer room that is separated from the maintenance room by a partition wall and has less floating dust than the maintenance room. 2. The clean transfer method according to claim 1, wherein the transfer port of the vacuum chamber is disposed movably and a transfer port of the vacuum chamber is provided on a side wall surface of the transfer chamber of the partition wall. (3) A movable vacuum clean box having a degree of vacuum of 1 Torr or less and a vacuum chamber are provided. The vacuum clean box and the vacuum chamber have a transfer port that can be hermetically coupled to each other . At the opening of the transfer port
Are provided with shutters, and those shutters protrude from each other in an airtight manner.
The vacuum clean box and the vacuum chamber
A clean transfer device having a configuration for communicating with a bar .