JP2000294529A - Foreign matter removal device for wafer surface - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To remove foreign matter attached to a wafer by cleaning the surface of the wafer. SOLUTION: A foreign matter removing device for a wafer surface transports a wafer 4 to a semiconductor exposure apparatus or the like by a transport device 2, and cleans a back surface 41 of the wafer 4 by a cleaning means 1 before placing the wafer 4 on a wafer mounting table. it can. The cleaning means 1 includes a moving mechanism 5 for moving the scrubber 3 in a three-dimensional space, a rotating mechanism 7 for rotating the scrubber 3, and a suction means 9 for sucking foreign matter removed by the scrubber 3. Before placing the scrubber 3 on the back surface 41 of the wafer 4, the scrubber 3 is brought into contact with the back surface 41 of the wafer 4 before being placed on the wafer mounting table.
The wafer 4 is moved over the entire surface of the wafer 1, cleaned, and the removed foreign matter is sucked by the suction means 9, so that the wafer 4 is kept flat even if it is placed on the wafer mounting table.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for removing foreign matter from a wafer surface, and more particularly to a method for removing foreign matter from one surface of a wafer when the wafer is mounted on a wafer mounting table of a semiconductor exposure apparatus, a film forming apparatus or another apparatus. The present invention relates to an apparatus for removing foreign matter.

[0002]

2. Description of the Related Art In a semiconductor exposure apparatus of this type, a wafer is placed on a wafer mounting table (XY stage), the back surface of the wafer is sucked on an XY stage, and the circuit pattern of the semiconductor device is exposed on the front surface of the wafer. It is provided as a device.

FIG. 7 is a view for explaining a state in which a wafer placed on an XY stage is exposed. This FIG.
The XY stage 102 of the semiconductor exposure apparatus 101
Then, when the wafer 111 is placed, the back surface 112 of the wafer 111 is sucked by the XY stage 102.

[0004] XY according to a certain control procedure.
The stage 102 is moved stepwise in a plane, and the chip forming region patterns 121, 122, 123,
.., 12n (n is an arbitrary integer) are sequentially exposed with a predetermined pattern. The wafer 111 has a size of, for example, 8 inches or 12 inches, and one chip formation region 121 has an area of, for example, about 20 mm × 20 mm.

When exposing a pattern to each of the chip forming region patterns 121, 122, 123,...
By detecting predetermined positions in 1, 122, 123,..., 12n, each of the patterns to be exposed in a superposed manner is accurately aligned and auto-focused so as to form an image.

However, as shown in FIG.
When the wafer 101a is placed on the XY stage 112 when the foreign matter 113 is attached to the back surface 112 of the
Since the thickness of the wafer 111 is, for example, about 600 to 700 μm, the part 114 where the foreign matter 113 is present rises due to the foreign matter 113 as shown in FIG.

At this time, the degree of swelling of the wafer 111a is small, and when the wafer 111a is within the range of the depth of focus of the semiconductor exposure apparatus 101, the auto focus normally operates. The focus does not operate normally, and the semiconductor circuit pattern does not form an accurate image. Thus, X
It is desirable that there be no foreign matter between the wafer mounting surface of the Y stage 102 and the wafer 111.

[0008] From such a concept, an apparatus for preventing foreign matter from remaining on the XY stage 102 has been proposed. This apparatus is provided with a cleaning means for cleaning a wafer mounting surface of an XY stage as described in, for example, Japanese Patent Application Laid-Open No. 5-82411. This conventional apparatus cleans the wafer mounting surface and removes foreign matter adhering to the wafer mounting surface before mounting the wafer on the wafer mounting surface of the exposure apparatus, thereby preventing foreign matter from adhering to the wafer. It is.

[0009]

However, in such a conventional apparatus, the foreign matter that has adhered to the wafer mounting surface is the foreign matter that originally adhered to the back surface of the wafer previously mounted on the wafer mounting surface. It is considered that it was attached to the mounting surface.

[0010] Further, since the wafer goes through various processes, there is a high possibility that foreign matter will adhere thereto.

Therefore, it can be said that cleaning the surface of the wafer before mounting it on the wafer mounting surface is more desirable than removing foreign substances on the wafer mounting surface in order to suppress the above-mentioned phenomenon.

SUMMARY OF THE INVENTION An object of the present invention is to provide an apparatus for removing foreign matter on a wafer surface, which can clean the surface of the wafer and remove foreign matter attached to the wafer.

[0013]

According to a first aspect of the present invention, there is provided an apparatus for removing foreign matter from a wafer surface, comprising the steps of: mounting a wafer on a wafer mounting table of a semiconductor exposure apparatus, a film forming apparatus, or another apparatus; A cleaning means for cleaning the surface of the wafer when the wafer is placed on the wafer. Therefore, according to the first aspect of the present invention, the wafer surface is cleaned by the cleaning means before the wafer is placed on the wafer mounting table, so that the wafer is kept flat even when it is mounted on the wafer mounting table. Become.

According to a second aspect of the present invention, in the first aspect, the cleaning means includes a scrubber capable of removing foreign matter on the surface of the wafer, and a movement for bringing the scrubber into contact with the wafer during cleaning and moving the wafer surface. And a suction means for sucking the foreign matter removed by the scrubber. The scrubber and the wafer come into contact during cleaning, foreign matter on the surface of the wafer is removed by the scrubber, and the removed foreign matter is sucked by suction means to prevent the foreign matter from scattering to the outside world.

According to a third aspect of the present invention, in the second aspect,
The scrubber has a brush for contacting the surface of the wafer, and has a mechanism for swinging or rotating the brush. The brush oscillates or rotates so that foreign matter on the wafer surface can be reliably removed.

According to a fourth aspect of the present invention, in the first aspect,
The cleaning means includes a cylindrical scrubber formed to have a width capable of contacting the entire surface of the wafer, a moving mechanism capable of relatively linearly moving the cylindrical scrubber and the wafer, and suctioning around the cylindrical scrubber. And a suction mechanism for causing the suction mechanism. The cylindrical scrubber contacts the surface of the wafer and moves relative to each other to remove foreign matter on the surface of the wafer, and the removed foreign matter is sucked by a suction mechanism to prevent scattering of the foreign matter.

According to a fifth aspect of the present invention, in the fourth aspect, the cylindrical scrubber is provided with a brush for contacting a wafer surface provided on a cylindrical surface, and a mechanism for rotating or rocking the cylindrical. It is characterized by having. By rotating or oscillating the brush that comes into contact with the surface of the wafer, it is possible to reliably remove foreign substances adhering to the surface of the wafer.

According to a sixth aspect of the present invention, in the first aspect, the cleaning means includes a fixed scrubber having a brush which is disposed in a transfer path through which the wafer is transferred, and has a brush through which the surface of the wafer passes. Suction means for suctioning foreign matter removed by the scrubber. In the present invention thus configured, since the scrubber is fixedly arranged, the structure can be simplified.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

<< First Embodiment >> FIG. 1 is a configuration diagram showing an apparatus for removing foreign matter from a wafer surface according to a first embodiment of the present invention. In FIG. 1, the foreign matter removing device on the wafer surface includes a cleaning means 1. The cleaning means 1 includes a moving mechanism 5 for moving the scrubber 3 in a three-dimensional space, a rotating mechanism 7 for rotating the scrubber 3, and a suction means 9 for sucking foreign matter removed by the scrubber 3.
And

The scrubber 3 is provided with a brush 32 on the surface of a tip portion 31 having a flat cylindrical shape. The brush 32 is free from static electricity and
It is made of a material that can reliably remove foreign matter.
Further, a space for sucking foreign matter is formed on the center side of the distal end portion 31. A cylindrical shaft 33 is provided at the center of rotation of the distal end portion 31, and is rotatable about the cylindrical shaft 33. Further, the space of the distal end portion 31 is communicated with the exhaust device 91 of the suction means 9 via the cylindrical shaft 33.

The moving mechanism 5 is capable of moving the distal end portion 31 of the scrubber 3 in the XY plane in the drawing, and is also movable in the Z axis direction (vertical direction) in the drawing. It is configured with a mechanism that allows 31 to move in a three-dimensional space. The moving mechanism 5
Includes an X-axis drive motor 51 that moves in the X-axis direction,
A Y-axis drive motor 52 for moving in the axial direction and a Z-axis drive motor 53 for moving in the Z-axis direction are provided. Also,
The moving mechanism 5 has an X for detecting movement in the X-axis direction.
A shaft encoder 55, a Y-axis encoder 56 for detecting movement in the Y-axis direction, and a Z-axis encoder 57 for detecting movement in the Z-axis direction are provided.

The moving mechanism 5 is provided with a rotating mechanism 7, and the rotating mechanism 7 is a mechanism for rotating the cylindrical shaft 33. The rotation mechanism 7 is provided with a rotation drive motor 71 that rotates the distal end portion 31 of the scrubber 3 around the cylindrical shaft 33 as a rotation center.

The suction means 9 is provided with a connecting mechanism 92 which communicates between an exhaust device 91 for exhausting and sucking and the cylindrical shaft 33.
And a hose 93 that connects and connects the connection mechanism 92 and the exhaust device 91.

The cleaning means 1 cleans the back surface 41 of the wafer 4 transferred by the transfer device 2. The transfer device 2 includes a wafer 4
Can be transferred to a wafer mounting table of a semiconductor exposure apparatus (not shown). That is, the transfer device 2 holds the wafer 4 by the holding mechanisms 21 and 21 and transfers the wafer 4 to the wafer mounting table of the semiconductor exposure apparatus (not shown). A wafer position detection sensor 11 is disposed in a wafer transfer path of the transfer device 2.
Stop position can be detected.

The output of the wafer position detection sensor 11 is input to the controller 15. The controller 15 includes an X-axis drive motor 51, a Y-axis drive motor 52,
The operation control of the shaft drive motor 53, the X-axis encoder 55, the Y-axis encoder 56, the rotation drive motor 71, the exhaust device 91, and the transport device 2 can be performed.

FIG. 2 is a block diagram showing a control system of the foreign matter removing device on the wafer surface. 2, the controller 15 includes a wafer position detection sensor 11, an X-axis encoder 55, a Y-axis encoder 56, and a Z-axis encoder 5.
7 and a sequence signal 151 of the semiconductor exposure apparatus.

The controller 15 can output an operation stop control signal to the transfer device 2 and a sequence signal 151 to the semiconductor exposure device. The controller 15 includes an X-axis drive motor 51, a Y-axis drive motor 5
2. The rotation of the Z-axis drive motor 53 and the rotation drive motor 71 can be controlled, or the operation of the exhaust device 91 can be controlled. A setting display 16 is connected to the controller 15 so that necessary information can be input and a processing result can be displayed.

The controller 15 includes, for example, a central processing unit (CPU), a main memory, a read-only memory, an input port, an output port, an external storage device, an analog / digital (A / D) converter, and a D / A converter. The information processing apparatus may include an information processing device having a container or the like. The processing program stored in the external storage device may be read into the main memory and processed, thereby performing the process of removing foreign substances on the wafer surface.

The operation of the thus configured foreign matter removing device for a wafer surface will be described with reference to FIGS. 1 and 2 and FIGS. FIG. 3 is a timing chart for explaining the operation of the foreign matter removing device on the wafer surface. The horizontal axis represents time, the vertical axis (a) represents a series of processes, and (b) represents the wafer position detection sensor 11. (C) shows the operation of the transport device 2, (d) shows the operation of the rotating mechanism and the suction means,
(E) shows the vertical movement of the scrubber 3, (f) shows the operation state of the X-axis drive motor 51 and the Y-axis drive motor 52, and (g)
Indicates a notification of cleaning start, and (h) indicates a notification of cleaning end. FIG. 4 is a flowchart for explaining the operation of the foreign matter removing device on the wafer surface.

First, when a command to transfer the wafer 4 is output from the semiconductor exposure apparatus, the transfer apparatus 2 starts operating (time t _{0 in} FIGS. 3A and 3C). At the same time, the controller 15 of the cleaning unit 1 starts operating (step S60 in FIG. 4). That is, the controller 1
5 starts the operation by the processing program arranged in the main memory. And the controller 1
5 waits for a detection signal from the wafer position detection sensor 11 to be input to the controller 15 (FIG. 4).
S61; NO).

Here, when a detection signal is input from the wafer position detection sensor 11 to the controller 15 and the signal state in FIG. 3B changes from "0" to "1" (S61 in FIG. 4; YES, time t ₁ in FIG. 3 (b),
The controller 15 stops the transport device 2 and notifies the semiconductor exposure device of the start of cleaning (FIG. 3).
(Times t _{1 in} (c) and (g)), and the exhaust device 91 is operated and the rotary drive motor 71 is rotated (time t ₂ in FIGS. 3D and 3E, S62 in FIG. 4). .

Then, based on the detection signal from the Z-axis encoder 57, the controller 15 determines whether or not the tip portion 31 of the scrubber 3 has moved (raised) to a predetermined position (S63 in FIG. 4).

Here, the controller 15 has a tip 31
Is in a standby state until it reaches a predetermined position (S6 in FIG. 4).
3; NO). When the controller 15 determines that the distal end portion 31 has reached the predetermined position (FIG. 3E)
At time t ₃ , S 63 in FIG. 4; YES), X based on the detection signals from the X-axis encoder 55 and the Y-axis encoder 56.
The drive of the shaft drive motor 51 and the Y-axis drive motor 52 is controlled (time t ₁ in FIG. 3 (f), S 64 in FIG. 4).

Then, the controller 15 determines whether or not the cleaning process on the entire rear surface of the wafer 4 has been completed based on the detection signals from the X-axis encoder 55 and the Y-axis encoder 56 (S65 in FIG. 4). The controller 15
When the cleaning process is not completed (S in FIG. 4)
65; NO), cleaning processing again (S64 in FIG. 4)
Return to

On the other hand, when the cleaning process is completed (S65 in FIG. 4; YES,
Of (f) the time t ₄₎ of, firstly, to stop the X-axis drive motor 51 and the Y-axis drive motor 52 (S66 in FIG. 4). At the same time, the controller 15 controls the Z-axis drive motor 53
Is rotated in reverse to lower the tip portion 31 of the scrubber 3 (S67, S68; NO in FIG. 4).

[0037] When the descent of the tip portion 31 is completed (S67 in FIG. 4; the time t ₅ of the (e) YES, FIG. 3),
The controller 15 includes a rotation drive motor 71 of the rotation mechanism 7.
The to start operation of the transport device 2 with stops (S69 in FIG. 4, the time t ₅ in (c), (d) 3), and notifies that the cleaning process has been completed in the semiconductor exposure apparatus ( S69 in FIG. 4, the time t ₅ of the (h) Figure 3).

In this way, the foreign matter on the back surface 41 of the wafer 4 can be removed. Therefore, even if the wafer is placed on the wafer mounting table of the semiconductor exposure apparatus, no inconvenience due to the foreign matter occurs and the reliability is high. A wafer with a good yield can be obtained. Moreover, in the embodiment, since the foreign matter removed by the scrubber 3 by the suction means 9 is removed by suction, the foreign matter does not scatter around and does not contaminate the exposure apparatus and other wafers.

In the first embodiment described above, the distal end portion 31 of the scrubber 3 moves in the three-dimensional space.
The configuration is not limited to this, and any configuration may be used as long as the wafer 4 and the scrubber 3 relatively move in a three-dimensional space. In the first embodiment, the scrubber 3 moves in the vertical and horizontal height directions. However, for example, the scrubber 3 may be fixed and the wafer 4 may move in the vertical and horizontal height directions. Further, the scrubber 3 moves vertically and horizontally,
The wafer 4 may be moved up and down.

Further, in the above-described first embodiment, an example is described in which a foreign matter removing device for a wafer surface is applied to a semiconductor exposure apparatus. However, the present invention is not limited to this. It can also be applied to

<< Second Embodiment >> FIG. 5 is a configuration diagram showing an apparatus for removing foreign matter from a wafer surface according to a second embodiment of the present invention. In the second embodiment shown in FIG. 5, the cleaning means 1a comprises a cylindrical scrubber 3a having a width capable of contacting the entire back surface 41 of the wafer 4.
A moving mechanism 5a that can relatively linearly move the cylindrical scrubber 3a and the wafer 4; a rotating mechanism 7 that rotates the cylindrical scrubber 3a; and a hood 91a that suctions the periphery of the cylindrical scrubber 3a. And a suction means 9 having

The cylindrical scrubber 3a is provided with a brush 38 which comes into contact with the entire back surface of the wafer 4 provided on the surface of the cylindrical body 37. That is, the cylindrical body 3
7 is formed to be longer than the diameter of the wafer 4.

In the second embodiment, the brush 38 of the cylindrical scrubber 3a contacts the back surface 41 of the wafer 4, the cylindrical scrubber 3a rotates, and the cylindrical scrubber 3a and the wafer 4 move relative to each other. By doing so, foreign matter on the back surface 41 of the wafer 4 is removed, and the removed foreign matter is sucked by the suction means 9 to prevent scattering of the foreign matter.

As described above, also according to the second embodiment,
Foreign matter adhering to the back surface 41 of the wafer 4 can be reliably removed.

In the first embodiment, the scrubber 3 is used.
In the second embodiment, the cylindrical scrubber 3a is rotated at the distal end portion 31. However, these may be swung.

<< Third Embodiment >> FIG. 6 is a perspective view of a main part of a foreign matter removing apparatus according to a third embodiment. The foreign matter removing device 1c according to this embodiment has a box-shaped frame 61 in which the scrubber 3c is open at the top, and a brush 62 is provided at the upper end of the frame 61. The frame 61 is formed longer than the diameter of the wafer 4 and is fixed, and the brush 62 is arranged in the transfer path of the wafer 4. For this reason, when the wafer 4 is carried into, for example, an exposure apparatus, the back surface 41 of the wafer 4 comes into contact with the brush 62. Also, at the bottom of the frame 61,
A suction hole (not shown) is formed, and one end of a suction pipe 63 is connected to the suction hole. The other end of the suction pipe 63 is connected to an exhaust device.

In the third embodiment configured as described above, when the wafer 4 is transferred and moved along the transfer path, the back surface 41 comes into contact with the brush 62 of the scrubber 3c, and the adhered foreign matter is removed. . In this embodiment, since the scrubber 3c is fixedly arranged, the structure can be simplified.

[0048]

As described above, according to the present invention, foreign substances adhering to the surface of the wafer are removed by the cleaning means, so that a highly reliable semiconductor device can be obtained and the semiconductor device can be manufactured. The advantage is that the yield is improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an apparatus for removing foreign matter from a wafer surface according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a control system of the foreign matter removal device for a wafer surface according to the first embodiment.

FIG. 3 is a timing chart for explaining the operation of the first embodiment.

FIG. 4 is a flowchart for explaining the operation of the first embodiment.

FIG. 5 is a configuration diagram illustrating an apparatus for removing foreign matter from a wafer surface according to a second embodiment of the present invention.

FIG. 6 is a perspective view of a main part of an apparatus for removing foreign matter from a wafer surface according to a third embodiment of the present invention.

FIG. 7 is a diagram for explaining a state in which a wafer mounted on an XY stage is exposed by a semiconductor exposure apparatus.

FIG. 8 is a diagram showing a state in which foreign matter is attached to a wafer.

FIG. 9 is a diagram for explaining disadvantages of the conventional device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 cleaning means 2 transfer device 3 scrubber 4 wafer 5 moving mechanism 7 rotation mechanism 9 suction means 11 wafer position detection sensor 15 controller 21 gripping mechanism 31 tip 32 brush 33 cylindrical axis 51 X axis encoder 52 Y axis drive motor 53 Z axis Drive motor 55 X-axis encoder 56 Y-axis encoder 57 Z-axis encoder 71 Rotary drive motor 91 Exhaust device 92 Connection mechanism 93 Hose

Claims (6)

[Claims] And a cleaning means for cleaning a surface of the wafer when the wafer is mounted on a wafer mounting table of a semiconductor exposure apparatus, a film forming apparatus, or another apparatus. Removal device. 2. A cleaning device comprising: a scrubber capable of removing foreign matter on a surface of a wafer; a moving mechanism for bringing the scrubber into contact with the wafer during cleaning and moving the wafer surface; and suctioning foreign matter removed by the scrubber. 2. The apparatus according to claim 1, further comprising a suction unit. 3. The apparatus according to claim 2, wherein the scrubber includes a brush for contacting the surface of the wafer, and a mechanism for swinging or rotating the brush. 4. The cleaning means includes: a cylindrical scrubber formed to have a width capable of contacting one entire surface of a wafer; a moving mechanism capable of relatively linearly moving the cylindrical scrubber and the wafer; 2. The apparatus according to claim 1, further comprising a suction mechanism for sucking around the scrubber. 5. The cylindrical scrubber is provided with a brush for contacting a wafer surface provided on the surface of the cylinder, and further comprising a rotating mechanism for rotating or swinging the cylinder. Foreign matter removal device for wafer surface. 6. The cleaning means comprises: a fixed scrubber provided in a transfer path along which a wafer is transferred, and having a brush through which the surface of the wafer passes, and suction means for sucking foreign matter removed by the scrubber. The foreign matter removal device for a wafer surface according to claim 1, further comprising: