JP2001188092A - Inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To exactly position a stage at a specific inspection objective position when a stage put by an inspection object is moved by an operation. SOLUTION: By adding sliding friction to the drive shaft of the stage, and adjusting the sliding friction added to the drive shaft, the stage put by the inspection object can be exactly positioned at the specific objective position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an inspection apparatus used for inspecting a semiconductor wafer or the like on which a predetermined device pattern is formed.

[0002]

2. Description of the Related Art A semiconductor device is manufactured by forming a fine device pattern on a semiconductor wafer. When such a device pattern is formed, dust or the like may adhere to the semiconductor wafer or may be damaged, thereby causing a defect. A semiconductor device having such a defect becomes a defective device and reduces the yield.

[0003] Therefore, in order to stabilize the yield of a production line at a high level, defects generated by dust and scratches are found at an early stage, the causes thereof are identified, and effective measures are taken for production facilities and production processes. It is preferable to take it.

[0004] Therefore, when a defect is found, an inspection device is used to check the type of the defect and classify the defect, thereby identifying the equipment or process that caused the defect. I have. Here, the inspection device for checking what the defect is is like an optical microscope, so to speak.
By looking at a defect in an enlarged manner, it tries to identify what the defect is.

[0005]

In an inspection apparatus for performing such an inspection, a semiconductor wafer having a predetermined device pattern formed thereon is mounted on a stage, and the stage on which the semiconductor wafer is mounted is moved. The operation guides the semiconductor wafer to a predetermined inspection target position.

Further, in this inspection apparatus, in order to guide the semiconductor wafer to a predetermined inspection target position, the position of the stage on which the semiconductor wafer is mounted is detected, and the stage is detected based on the detected signal. Is moved to a predetermined inspection target position, that is, a so-called positioning servo is performed. In this positioning servo, as shown in FIG. 16, the stage is moved within the range of 0 count where the predetermined inspection target position P is located, and then the servo loop is turned ON within the range of 0 count. , The stage is guided to the inspection target position P.

However, in the positioning servo, when the stage is located near the boundary between ± 1 count and adjacent to 0 count, the servo gain is high. Although approaching the target position P, it may be accelerated and pass the inspection target position P, and jump into the opposite +1 count side. For this reason, in the inspection device, the stage may stop at a position shifted by a few counts from the inspection target position P, or the stage may not converge on the inspection target position P, and a minute vibration may occur on the stage.

[0008] Therefore, in the conventional inspection apparatus, the stage on which the semiconductor wafer is mounted cannot be accurately positioned at a predetermined inspection target position, and the inspection capability may be greatly reduced.

In particular, device patterns formed on semiconductor wafers are becoming finer as semiconductor devices become more highly integrated, and it becomes increasingly difficult to accurately position a semiconductor wafer at a predetermined inspection target position. ing. As shown in FIG. 16, the width of each count in the positioning servo is about 50 nm.

In addition, since the inspection apparatus inspects a semiconductor wafer on which such a fine device pattern is formed, even a slight vibration of the stage described above may cause a serious obstacle to the inspection.

Therefore, the present invention has been proposed in view of such conventional circumstances, and when moving a stage on which an object to be inspected is moved, the stage is accurately positioned at a predetermined inspection object position. An object of the present invention is to provide an inspection device capable of performing positioning.

[0012]

The inventor of the present invention has made intensive studies to achieve the above object, and as a result, added sliding resistance to the drive shaft of the stage, and added the sliding resistance to the drive shaft. It has been found that the stage on which the inspection object is placed can be accurately positioned at a predetermined inspection object position by adjusting the distance.

That is, the inspection apparatus according to the present invention is created based on the above knowledge, and controls the stage on which the inspection object is mounted and the stage on which the inspection object is mounted. A stage moving unit for moving the stage to a predetermined inspection target position, and a sliding contact resistance adding unit for adjusting the sliding contact resistance to the drive shaft of the stage moving unit. .

In this inspection device, the sliding contact resistance adding means includes:
Since a predetermined sliding contact resistance is added to the drive shaft of the stage moving means, the stage moved by the stage moving means can be accurately positioned at a predetermined inspection target position. Further, by making the sliding resistance added to the drive shaft adjustable, the sliding resistance added to the drive shaft can be easily adjusted.

[0015]

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

FIG. 1 shows the appearance of an inspection apparatus to which the present invention is applied. This inspection apparatus 1 is for inspecting a semiconductor wafer on which a predetermined device pattern is formed,
When a defect is found in a device pattern formed on a semiconductor wafer, the defect is determined by examining what the defect is.

As shown in FIG. 1, the inspection apparatus 1 includes a clean unit 2 for keeping an environment for inspecting a semiconductor wafer clean. The clean unit 2 includes a clean box 3 formed by bending a stainless steel plate or the like to form a hollow box, and a clean air unit 4 integrally provided above the clean box 3.

The clean box 3 is provided with a window 3a at a predetermined location so that an inspector can visually recognize the inside of the clean box 3 from the window 3a.

The clean air unit 4 is for supplying clean air into the clean box 3, and has two blowers 5a and 5b respectively disposed at different positions on the upper portion of the clean box 3, and these blowers 5a, 5
b and an air filter (not shown) disposed between the clean box 3. The air filter is, for example, a HEPA filter (High Efficiency Particulate).
Air Filter) and ULPA Filter (Ultra Low Penetrat)
ion Air Filter). The clean air unit 4 is provided with blowers 5a, 5b
The dust and the like in the air blown by the above are removed by a high-performance air filter and supplied as clean air into the clean box 3.

In the clean unit 2, the amount of clean air supplied from the clean air unit 4 into the clean box 3 is controlled individually for each of the two blowers 5a and 5b. It is possible to appropriately control the airflow. Here, an example in which the clean air unit 4 includes two blowers 5a and 5b will be described. However, the number of blowers may be determined according to the size and shape of the clean box 3, and three or more blowers are provided. It may be configured. In this case, in the inspection device 1, the amount of clean air supplied from the clean air unit 4 into the clean box 3 is individually controlled for each blower.

In the clean unit 2, the clean box 3 is supported on the floor plate by the support legs 6,
Its lower end is open. In the clean unit 2, the air supplied from the clean air unit 4 into the clean box 3 is mainly discharged from the lower end of the clean box 3 to the outside of the clean box 3. An opening region 3b is provided at a predetermined position on a side surface of the clean box 3 so that air supplied from the clean air unit 4 into the clean box 3 is supplied to the clean box 3.
Is also discharged to the outside from the opening region 3b provided on the side surface of the.

The clean unit 2 always supplies clean air from the clean air unit 4 to the clean box 3 as described above, and circulates air circulated in the clean box 3 as an air flow to the outside of the clean box 3. To drain. As a result, dust and the like generated in the clean box 3 are discharged to the outside of the clean box 3 together with the air, so that the internal environment of the clean box 3 is maintained at a very high degree of cleanness, for example, about class 1. . Further, the inside pressure of the clean box 3 is always maintained at a positive pressure in order to prevent air containing dust and the like from entering from the outside.

In the inspection apparatus 1, as shown in FIG. 2, the apparatus main body 10 is housed inside the clean box 3, and the apparatus main body 10 is stored in the clean box 3.
Thus, inspection of a semiconductor wafer on which a predetermined device pattern is formed is performed. here,
A semiconductor wafer to be inspected is placed in a predetermined closed container 7.
, And transferred through the container 7 to the inside of the clean box 3. FIG. 2 is a side view showing the apparatus main body 10 disposed inside the clean box 3 as viewed from the direction of arrow A1 in FIG.

The container 7 has a bottom 7a, a cassette 7b fixed to the bottom 7a, and a cover 7c detachably engaged with the bottom 7a to cover the cassette 7b. The semiconductor wafers to be inspected are mounted on the cassette 7b such that a plurality of the semiconductor wafers are overlapped at a predetermined interval, and are sealed by the bottom 7a and the cover 7c.

When inspecting a semiconductor wafer,
First, a container 7 containing a semiconductor wafer is installed in a container installation space 8 provided at a predetermined position of the clean box 3. In the container installation space 8, an upper surface of an elevator 22a of an elevator 22 to be described later is
The container 7 is installed in the container installation space 8 such that the bottom 7a is located on the elevator 22a of the elevator 22.

When the container 7 is set in the container setting space 8, the engagement between the bottom 7a of the container 7 and the cover 7c is released. When the elevator 22a of the elevator 22 is lowered in the direction of arrow B in FIG. 2, the bottom 7a of the container 7 and the cassette 7b are separated from the cover 7c and moved into the clean box 3. Thereby, the semiconductor wafer to be inspected is transferred into the clean box 3 without being exposed to the outside air.

When the semiconductor wafer is transferred into the clean box 3, the semiconductor robot to be inspected is taken out of the cassette 7b and inspected by the transfer robot 23 described later.

As described above, the inspection apparatus 1 inspects the semiconductor wafer inside the clean box 3 maintained at a high degree of cleanliness. Inconveniences such as obstruction of a simple test can be effectively avoided. In addition, the semiconductor wafer to be inspected is placed in a sealed container 7 and transported, and the semiconductor wafer is transferred into the clean box 3 via the container 7. If only the inside of the container 7 is maintained at a sufficient degree of cleanness, it is possible to effectively prevent dust and the like from adhering to the semiconductor wafer without increasing the cleanliness of the entire environment in which the inspection device 1 is installed. .

By locally increasing only the degree of cleanliness at a necessary place in this way, it is possible to realize a high degree of cleanliness and to significantly reduce the cost for realizing a clean environment. The mechanical interface between the closed container 7 and the clean box 3 is a so-called SMIF (standard mechanical interface).
ace) is preferable, and in that case, a so-called SMIF-POD is used as the closed container 7.

Further, as shown in FIG. 1, the inspection apparatus 1 includes an external unit 50 in which a computer for operating the apparatus main body 10 is arranged. The external unit 50 is installed outside the clean box 3 and is supported on a floor plate by support legs 51. The external unit 50 includes a display device 52 for displaying an image or the like obtained by capturing an image of a semiconductor wafer, a display device 53 for displaying various conditions at the time of inspection, and inputting an instruction to the device body 10. Input device 54 and the like are also provided. The inspector who inspects the semiconductor wafer inputs necessary instructions from the input device 54 arranged on the external unit 50 while viewing the display devices 52 and 53 arranged on the external unit 50, and inspects the semiconductor wafer. I do.

Next, the apparatus body 10 provided inside the clean box 3 will be described in detail.

As shown in FIG. 2, the apparatus main body 10 has a support 11. The support base 11 is used to
Is a table for supporting each of the mechanisms. A support leg 12 is attached to the bottom of the support base 11.
And each mechanism provided on the support base 11 supports the support leg 1
2 has a structure supported on a floor plate independently of the clean box 3.

On the support table 11, via a vibration isolation table 13,
An inspection stage 14 on which a semiconductor wafer to be inspected is placed is provided.

The anti-vibration table 13 is for suppressing vibration from the floor, vibration generated when the inspection stage 14 is moved, and the like. And a plurality of movable legs 13b for supporting the stone surface plate 13a. And this vibration isolation table 13
When the vibration occurs, the vibration is detected and the movable leg 13b is detected.
Is driven to quickly cancel the vibration of the stone base 13a and the inspection stage 14 installed on the stone base 13a.

In the inspection apparatus 1, since a semiconductor wafer on which a fine device pattern is formed is inspected, even a slight vibration may hinder the inspection. In particular, since the inspection apparatus 1 performs inspection at a high resolution using ultraviolet light, the influence of vibration is likely to be large. Therefore, in the inspection apparatus 1, by installing the inspection stage 14 on the anti-vibration table 13, even if a slight vibration occurs in the inspection stage 14, the vibration is quickly canceled out, and the vibration is reduced. Influence is suppressed, and the inspection capability at the time of performing inspection at high resolution using ultraviolet light is improved.

The inspection stage 14 is placed on the vibration isolation table 13.
In order to stably install the vibration isolator, it is desirable that the center of gravity of the vibration isolation table 13 is located at a somewhat lower position. Therefore, in this inspection device 1, the notch 13 is formed at the lower end of the stone platen 13a.
c is provided so that the movable leg 13b supports the stone surface plate 13a at the notch 13c, thereby lowering the center of gravity of the vibration isolation table 13.

It should be noted that vibrations and the like generated when the inspection stage 14 is moved can be predicted to some extent in advance. If the vibration isolation table 13 is operated by predicting such vibrations in advance, it is possible to prevent the vibrations occurring on the inspection stage 14 from occurring. Therefore, it is desirable that the inspection apparatus 1 operates the anti-vibration table 13 by predicting in advance vibrations and the like that occur when the inspection stage 14 is moved.

The inspection stage 14 is a stage for supporting a semiconductor wafer to be inspected. The inspection stage 14 has a function of supporting a semiconductor wafer to be inspected and a function of moving the semiconductor wafer to a predetermined inspection target position.

Specifically, the inspection stage 14 includes an X stage 15 installed on the vibration isolation table 13 and an X stage 1
5, a Y stage 16 installed on the Y stage 16, a θ stage 17 installed on the Y stage 16, a Z stage 18 installed on the θ stage 17, and a suction plate 19 installed on the Z stage 18. Have.

The X stage 15 and the Y stage 16 are stages that move in the horizontal direction.
The stage 16 moves semiconductor wafers to be inspected in directions orthogonal to each other, and guides a device pattern to be inspected to a predetermined inspection position.

The .theta. Stage 17 is a so-called rotary stage for rotating a semiconductor wafer.
When inspecting the semiconductor wafer, the semiconductor wafer is rotated by the θ stage 17 so that, for example, the device pattern on the semiconductor wafer is horizontal or vertical to the screen.

The Z stage 18 is a stage that moves in the vertical direction and adjusts the height of the stage. When inspecting a semiconductor wafer, the Z stage 18 is used to adjust the inspection surface of the semiconductor wafer to an appropriate height.
Adjust the height of the stage.

The suction plate 19 is for sucking and fixing the semiconductor wafer to be inspected. During the inspection of the semiconductor wafer, the semiconductor wafer to be inspected is placed on the suction plate 19 and is sucked by the suction plate 18 to suppress unnecessary movement.

An optical unit 21 supported by a support member 20 is disposed on the vibration isolation table 12 so as to be positioned on the inspection stage 14. The optical unit 21 is for taking an image of a semiconductor wafer when inspecting the semiconductor wafer. The optical unit 21 has a function of capturing an image of a semiconductor wafer to be inspected at low resolution using visible light, and a function of capturing an image of a semiconductor wafer to be inspected at high resolution using ultraviolet light. It also has the function to perform.

As shown in FIGS. 2 and 3, an elevator 22 for taking out a cassette 7b on which a semiconductor wafer to be inspected is mounted from the container 7 and moving the cassette 7b into the clean box 3, as shown in FIGS. Is provided. Further, as shown in FIG. 3, a transfer robot 23 for transferring the semiconductor wafer, and centering and phase setting of the semiconductor wafer before placing the semiconductor wafer on the inspection stage 14 are provided on the support base 11 as shown in FIG. Is provided. FIG. 3 is a plan view schematically showing the apparatus main body 10 provided inside the clean box 3.

The elevator 22 has a lifting platform 22a that can be raised and lowered, and the container 7 is installed in the container installation space 8 of the clean box 3 and the bottom 7 of the container 7
a when the engagement between the cover a and the cover 7c is released.
The lower portion 2a is operated to lower the bottom portion 7a of the container 7.
Then, the cassette 7b fixed thereto is moved into the clean box 3.

The transfer robot 23 has an operation arm 23b provided with a suction mechanism 23a at the distal end thereof. The operation arm 23b is moved and operated by the suction mechanism 23a provided at the distal end. The wafer is sucked, and the semiconductor wafer is transported in the clean box 3.

The pre-aligner 24 performs phase and centering of the semiconductor wafer with reference to an orientation flat and a notch formed in advance on the semiconductor wafer. The inspection apparatus 1 sets the pre-aligner 24 before placing the semiconductor wafer on the inspection stage 14.
In this way, the efficiency of the inspection is improved by performing the phase setting or the like.

When the semiconductor wafer is set on the inspection stage 14, first, the bottom 7 a of the container 7 and the cassette 7 b are moved into the clean box 3 by the elevator 22. Then, a semiconductor wafer to be inspected is selected from the plurality of semiconductor wafers mounted on the cassette 7b, and the selected semiconductor wafer is taken out of the cassette 7b by the transfer robot 23.

The semiconductor wafer taken out of the cassette 7b is transferred to the pre-aligner 24 by the transfer robot 23. The semiconductor wafer conveyed to the pre-aligner 24 is subjected to phase setting and center setting by the pre-aligner 24. Then, the semiconductor wafer on which the phase setting and the center setting have been performed is transferred to the inspection stage 14 by the transfer robot 23, and is placed on the suction plate 19 to perform the inspection.

When the semiconductor wafer to be inspected is transported to the inspection stage 14, the semiconductor wafer to be inspected next is taken out of the cassette 7b by the transport robot 23 and transported to the pre-aligner 24. Then, while the inspection of the semiconductor wafer previously conveyed to the inspection stage 14 is being performed, the phase of the semiconductor wafer to be inspected next and the centering are performed. When the inspection of the semiconductor wafer previously transported to the inspection stage 14 is completed, the next semiconductor wafer to be inspected is immediately transported to the inspection stage 14.

In the inspection apparatus 1, as described above, before the semiconductor wafer to be inspected is transported to the inspection stage 14,
By performing phase setting and center setting by the pre-aligner 24 in advance, the time required for positioning the semiconductor wafer by the inspection stage 14 can be reduced. Further, in the inspection apparatus 1, the semiconductor wafer to be inspected next is taken out of the cassette 7 b using the time during which the semiconductor wafer previously conveyed to the inspection stage 14 is being inspected, and the phase is determined by the pre-aligner 24. By performing the centering and the centering, the overall time can be reduced, and the inspection can be performed efficiently.

In the inspection apparatus 1, the elevator 22, the transfer robot 23, the pre-aligner 2
4 are installed on the support base 11 so as to be lined up in a straight line, as shown in FIG. The respective installation positions are determined so that the distance L1 between the elevator 22 and the transfer robot 23 is substantially equal to the distance L2 between the transfer robot 23 and the pre-aligner 24. Further, from the viewpoint of the transfer robot 23,
The inspection stage 14 is arranged in a direction substantially orthogonal to the direction in which the elevators 22 and the pre-aligners 24 are arranged.

The inspection apparatus 1 can quickly and accurately transport a semiconductor wafer, which is an object to be inspected, by arranging each mechanism as described above.

That is, in the inspection apparatus 1, since the distance L1 between the elevator 22 and the transfer robot 23 is substantially equal to the distance L2 between the transfer robot 23 and the pre-aligner 24, Transfer robot 23
Without changing the length of the arm 23b of the cassette 7b.
The semiconductor wafer taken out of the wafer can be transferred to the pre-aligner 24. Therefore, in the inspection apparatus 1, since an error or the like generated when the length of the arm 23b of the transfer robot 23 is changed does not matter, the operation of transferring the semiconductor wafer to the pre-aligner 24 can be performed accurately. Further, since the elevator 22, the transfer robot 23, and the pre-aligner 24 are arranged in a straight line, the transfer robot 23 can transfer the semiconductor wafer taken out of the cassette 7b to the pre-aligner 24 only by linear movement. . Therefore, in the inspection apparatus 1, the operation of transporting the semiconductor wafer to the pre-aligner 24 can be performed extremely accurately and quickly.

Further, in the inspection apparatus 1, the elevator 22 and the pre-aligner 24 are viewed from the transfer robot 23.
Are arranged so that the inspection stage 14 is positioned in a direction substantially perpendicular to the direction in which the semiconductor wafers are arranged, so that the semiconductor wafer is transported to the inspection stage 14 by the linear movement of the transport robot 23. be able to. Therefore,
In this inspection apparatus 1, a semiconductor wafer is placed on an inspection stage 1
4 can be performed very accurately and quickly. In particular, the inspection apparatus 1 inspects a semiconductor wafer on which a fine device pattern is formed.
Since the transfer and positioning of the semiconductor wafer to be inspected must be performed very accurately, the above arrangement is very effective.

In the inspection device 1, tires 25 are provided at the bottom of the clean box 3, the support base 11, and the external unit 50, respectively. Thereby, in the inspection apparatus 1, the clean unit 2, the apparatus main body 10, and the external unit 50 can be easily moved. When fixing the inspection apparatus 1, as shown in FIGS. 1 and 2, the support legs 6, 12, and 51 are put on the floor, and the tire 25 is floated.

Next, the inspection apparatus 1 will be described in more detail with reference to the block diagram of FIG.

As shown in FIG. 4, an external unit 50 of the inspection apparatus 1 has an image processing computer 60 connected to a display device 52 and an input device 54a, and a control device connected to a display device 53 and an input device 54b. Computer 61
And are arranged. In FIG. 1, the input device 54a connected to the image processing computer 60 and the input device 54b connected to the control computer 61 are collectively shown as the input device 54.

When inspecting a semiconductor wafer, the computer 60 for image processing uses a CCD (charge-coupled device) camera 30 installed inside the optical unit 21,
A computer that takes in and processes an image obtained by imaging a semiconductor wafer by 31. That is, this inspection device 1
Performs inspection of the semiconductor wafer by processing and analyzing the image of the semiconductor wafer captured by the CCD cameras 30 and 31 installed inside the optical unit 21 by the image processing computer 60.

The input device 54a connected to the image processing computer 60 is used to input, to the image processing computer 60, instructions necessary for analyzing images captured from the CCD cameras 30 and 31. And comprises, for example, a pointing device such as a mouse, a keyboard, and the like. The display device 52 connected to the image processing computer 60 is for displaying analysis results of images captured from the CCD cameras 30 and 31, and is composed of, for example, a CRT display or a liquid crystal display.

When inspecting the semiconductor wafer, the control computer 61 performs the inspection stage 14, the elevator 2
2. A computer for controlling the transfer robot 23, the pre-aligner 24, and each device inside the optical unit 21, and the like. That is, the inspection apparatus 1 controls the control computer so that an image of the semiconductor wafer to be inspected is picked up by the CCD cameras 30 and 31 installed inside the optical unit 21 when inspecting the semiconductor wafer. 61, the inspection stage 14, the elevator 2
2. It controls the transfer robot 23, the pre-aligner 24, and each device inside the optical unit 21.

The control computer 61 has a function of controlling the blowers 5a and 5b of the clean air unit 4. That is, the inspection apparatus 1 controls the blowers 5 a and 5 b of the clean air unit 4
Is controlled to constantly supply clean air into the clean box 3 when inspecting a semiconductor wafer,
Further, the air flow in the clean box 3 can be controlled.

The input device 54 b connected to the control computer 61 includes the inspection stage 14, the elevator 22, the transport robot 23 and the pre-aligner 24, each device inside the optical unit 21, and the blower of the clean air unit 4. This is for inputting an instruction necessary for controlling 5a, 5b and the like to the control computer 61, and includes, for example, a pointing device such as a mouse or a keyboard. The control computer 6
The display device 53 connected to 1 is for displaying various conditions and the like at the time of inspection of a semiconductor wafer.
It consists of an RT display, a liquid crystal display and the like.

The image processing computer 60 and the control computer 61 can exchange data with each other by a memory link mechanism. That is,
Image processing computer 60 and control computer 61
Are connected to each other via memory link interfaces 60a and 61a provided respectively, so that data can be exchanged between the image processing computer 60 and the control computer 61.

On the other hand, inside the clean box 3 of the inspection apparatus 1, the semiconductor wafer placed in the sealed container 7 and transported is taken out from the cassette 7 b of the container 7 and set on the inspection stage 14. As described above, the elevator 22, the transfer robot 23, and the pre-aligner 24 are arranged as mechanisms. These are connected to a control computer 61 arranged in the external unit 50 via a robot control interface 61b.
Then, control signals are sent from the control computer 61 to the elevator 22, the transfer robot 23, and the pre-aligner 24 via the robot control interface 61b.

That is, the semiconductor wafers conveyed in the closed container 7 are transferred to the cassette 7 of the container 7.
b, when it is taken out and installed on the inspection stage 14,
Control signals are sent from the control computer 61 to the elevator 22, the transfer robot 23, and the pre-aligner 24 via the robot control interface 61b. Then, the elevator 22, the transfer robot 23, and the pre-aligner 24 operate based on the control signal, and as described above, the semiconductor wafers that have been transported in the closed container 7 are transferred to the cassette 7b of the container 7. , And the phase and center are set by the pre-aligner 25 and set on the inspection stage 14.

Further, an anti-vibration table 13 is provided inside the clean box 3 of the inspection apparatus 1, and the X-stage 15 and the Y-stage 1
6, an inspection stage 14 including a θ stage 17, a Z stage 18, and a suction plate 19 is provided.

Here, the X stage 15 and the Y stage 1
6, the θ stage 17, the Z stage 18, and the suction plate 19 are connected to a control computer 61 arranged in the external unit 50 via a stage control interface 61c. Then, control signals are sent from the control computer 61 to the X stage 15, the Y stage 16, the θ stage 17, the Z stage 18, and the suction plate 19 via the stage control interface 61c.

That is, when inspecting a semiconductor wafer, control signals are sent from the control computer 61 to the X stage 15, the Y stage 16, the θ stage 17, the Z stage 18, and the suction plate 19 via the stage control interface 61c. Sent out. And X stage 1
5, Y stage 16, θ stage 17, Z stage 18
The suction plate 19 operates on the basis of the control signal to suck and fix the semiconductor wafer to be inspected by the suction plate 19, and the semiconductor stage is controlled by the X stage 15, the Y stage 16, the θ stage 17 and the Z stage 18. The wafer is moved to a predetermined position, angle and height.

As described above, the optical unit 21 is also provided on the vibration isolation table 12. The optical unit 21 is for taking an image of the semiconductor wafer at the time of inspecting the semiconductor wafer, and as described above, the function of taking an image of the semiconductor wafer to be inspected at a low resolution using visible light. And a function of capturing an image of a semiconductor wafer to be inspected with high resolution using ultraviolet light.

The optical unit 21 is a mechanism for capturing an image of a semiconductor wafer with visible light, a visible light CCD camera 30, a halogen lamp 32, a visible light optical system 33, and a visible light objective. A lens 34 and a visible light autofocus control unit 35 are provided.

When an image of the semiconductor wafer is taken with visible light, the halogen lamp 32 is turned on. Here, the driving source of the halogen lamp 32 is the external unit 50.
Is connected via a light source control interface 61d to a control computer 61 arranged in the computer. The driving source of the halogen lamp 32 includes the control computer 6.
1 transmits a control signal via the light source control interface 61d. The turning on / off of the halogen lamp 32 is performed based on this control signal.

When taking an image of a semiconductor wafer with visible light, the halogen lamp 32 is turned on, and the visible light from the halogen lamp 32 is transmitted to the visible light optical system 33.
Then, the semiconductor wafer is illuminated by being applied to the semiconductor wafer via the visible light objective lens 34. Then, the image of the semiconductor wafer illuminated by the visible light is converted into a visible light objective lens 34.
And enlarges the enlarged image with the visible light CCD camera 30.
To capture an image.

Here, the visible light CCD camera 30 is connected to an image processing computer 60 provided in the external unit 50.
Are connected via an image capture interface 60b. Then, the image of the semiconductor wafer captured by the visible light CCD camera 30 is captured by the image processing computer 60 via the image capturing interface 60b.

When the image of the semiconductor wafer is captured with visible light as described above, the automatic focus position is adjusted by the visible light autofocus controller 35. That is, the visible light autofocus control unit 35 detects whether or not the distance between the visible light objective lens 34 and the semiconductor wafer matches the focal length of the visible light objective lens 34. Is a visible light objective lens 34
Alternatively, the Z stage 18 is moved so that the inspection target surface of the semiconductor wafer coincides with the focal plane of the visible light objective lens 34.

Here, the visible light auto-focus control unit 35 sends an auto-focus control interface 61 to a control computer 61 arranged in the external unit 50.
e. Then, a control signal is sent from the control computer 61 to the visible light autofocus control unit 35 via the autofocus control interface 61e. Automatic focus positioning of the visible light objective lens 34 by the visible light autofocus controller 35 is performed based on this control signal.

The optical unit 21 includes a CCD camera 31 for ultraviolet light, an ultraviolet laser light source 36, an optical system 37 for ultraviolet light, and a mechanism for capturing an image of a semiconductor wafer with ultraviolet light. An optical objective lens 38 and an ultraviolet auto focus control unit 39 are provided.

When an image of the semiconductor wafer is taken with ultraviolet light, the ultraviolet laser light source 36 is turned on. Here, the drive source of the ultraviolet laser light source 36 is connected to a control computer 61 arranged in the external unit 50 via a light source control interface 61d. A control signal is sent from the control computer 61 to the drive source of the ultraviolet laser light source 36 via the light source control interface 61d. Turning on / off the ultraviolet laser light source 36
The light is turned off based on this control signal.

It is preferable that the ultraviolet laser light source 36 emits an ultraviolet laser having a wavelength of about 266 nm. An ultraviolet light laser having a wavelength of about 266 nm is obtained as a fourth harmonic of a YAG laser. Further, a laser light source having an oscillation wavelength of about 166 nm has been developed, and such a laser light source may be used as the ultraviolet laser light source.

When capturing an image of a semiconductor wafer with ultraviolet light, the ultraviolet laser light source 36 is turned on, and the ultraviolet light from the ultraviolet laser light source 36 is transmitted to the ultraviolet optical system 37 and the objective lens for ultraviolet light. The semiconductor wafer is illuminated by being applied to the semiconductor wafer via 38. Then, the image of the semiconductor wafer illuminated by the ultraviolet light is enlarged by the ultraviolet light objective lens 38, and the enlarged image is captured by the ultraviolet light CCD camera 31.

Here, the ultraviolet CCD camera 31 is connected to the image processing computer 60 provided in the external unit 50.
Are connected via an image capture interface 60c. The image of the semiconductor wafer captured by the ultraviolet light CCD camera 31 is captured by the image processing computer 60 via the image capturing interface 60c.

When the image of the semiconductor wafer is picked up by the ultraviolet light as described above, the automatic focus control is performed by the ultraviolet light autofocus control section 39. That is, the autofocus controller 39 for ultraviolet light detects whether or not the interval between the objective lens 38 for ultraviolet light and the semiconductor wafer matches the focal length of the objective lens 38 for ultraviolet light. Is the objective lens 38 for ultraviolet light.
Alternatively, the Z stage 18 is moved so that the inspection surface of the semiconductor wafer coincides with the focal plane of the ultraviolet light objective lens 38.

Here, the auto-focus control section 39 for ultraviolet light transmits an auto-focus control interface 61 to a control computer 61 arranged in the external unit 50.
e. Then, a control signal is sent from the control computer 61 to the ultraviolet light autofocus control section 39 via the autofocus control interface 61e. Automatic focusing of the ultraviolet light objective lens 38 by the ultraviolet light autofocus control unit 39 is performed based on this control signal.

Further, as described above, the clean air unit 4 is provided with two blowers 5a and 5b. These blowers 5a and 5b are connected to a control computer 61 arranged in the external unit 50 via an air volume control interface 61f. A control signal is sent from the control computer 61 to the blowers 5a and 5b of the clean air unit 4 via the air volume control interface 61f. Control of the number of rotations of the blowers 5a and 5b, switching on / off, and the like are performed based on this control signal.

Next, the optical unit 21 of the inspection apparatus 1
Will be described in more detail with reference to FIG. Here, the auto focus control units 35 and 3
The description of 9 will be omitted, and an optical system for illuminating the semiconductor wafer to be inspected and an optical system for imaging the semiconductor wafer to be inspected will be described.

As shown in FIG. 5, the optical unit 21
As an optical system for capturing an image of a semiconductor wafer with visible light, a halogen lamp 32 and an optical system 33 for visible light are used.
And a visible light objective lens 34.

The visible light from the halogen lamp 32 is guided by the optical fiber 40 to the visible light optical system 33.
The visible light guided to the visible light optical system 33 first passes through the two lenses 41 and 42 and enters the half mirror 43. Then, the visible light incident on the half mirror 43 is
The light is reflected by the half mirror 43 toward the objective lens 34 for visible light, and enters the semiconductor wafer via the objective lens 34 for visible light. Thereby, the semiconductor wafer is illuminated with the visible light.

Then, the image of the semiconductor wafer illuminated by the visible light is enlarged by the visible light objective lens 34,
The light passes through the half mirror 43 and the imaging lens 44 and is imaged by the visible light CCD camera 30. That is,
The reflected light from the semiconductor wafer illuminated by visible light
The light enters the visible light CCD camera 30 via the visible light objective lens 34, the half mirror 43, and the imaging lens 44.
The image is taken by the D camera 30. And C for visible light
An image of the semiconductor wafer (hereinafter, referred to as a visible image) captured by the CD camera 30 is sent to the image processing computer 60.

The optical unit 21 includes an ultraviolet laser light source 36, an ultraviolet optical system 37, and an ultraviolet objective lens 38 as an optical system for capturing an image of a semiconductor wafer with ultraviolet light. Have.

Ultraviolet light from the ultraviolet laser light source 36 is guided to the ultraviolet light optical system 37 by the optical fiber 45.
The ultraviolet light guided to the ultraviolet light optical system 37 first passes through the two lenses 46 and 47 and enters the half mirror 48. Then, the visible light incident on the half mirror 48 is
The light is reflected by the half mirror 48 toward the ultraviolet light objective lens 38 and is incident on the semiconductor wafer via the ultraviolet light objective lens 38. Thereby, the semiconductor wafer is illuminated by the ultraviolet light.

Then, the image of the semiconductor wafer illuminated with the ultraviolet light is enlarged by the ultraviolet light objective lens 38,
The light passes through the half mirror 48 and the imaging lens 49 and is imaged by the ultraviolet light CCD camera 31. That is,
The reflected light from the semiconductor wafer illuminated by ultraviolet light,
The light enters the ultraviolet light CCD camera 31 via the ultraviolet light objective lens 38, the half mirror 48, and the imaging lens 49, whereby the enlarged image of the semiconductor wafer is converted to the ultraviolet light CC.
The image is captured by the D camera 31. And UV light C
The image of the semiconductor wafer (hereinafter, referred to as an ultraviolet image) captured by the CD camera 31 is sent to the image processing computer 60.

In the inspection apparatus 1 as described above, an image of a semiconductor wafer can be imaged and inspected by ultraviolet light having a wavelength shorter than that of visible light. As compared with the case of performing classification, finer defects can be detected and classified.

In addition, the inspection apparatus 1 has both an optical system for visible light and an optical system for ultraviolet light, and inspects a semiconductor wafer at a low resolution using visible light and uses an ultraviolet light. Inspection of a semiconductor wafer with high resolution can be performed. Therefore, the inspection apparatus 1 detects and classifies large defects by inspecting a semiconductor wafer at low resolution using visible light, and inspects a semiconductor wafer at high resolution using ultraviolet light. It is also possible to detect and classify small defects.

In the inspection apparatus 1, the numerical aperture NA of the ultraviolet light objective lens 40 is preferably large.
For example, it is set to 0.9 or more. As described above, by using a lens having a large numerical aperture NA as the ultraviolet light objective lens 40, it is possible to detect a finer defect.

When a defect of a semiconductor wafer is composed of only irregularities without color information such as a scratch, the defect can hardly be seen with light having no coherence. On the other hand, when light having excellent coherence, such as laser light, is used, even when a defect such as a scratch has no color information and consists only of irregularities, light is generated in the vicinity of the irregularities. By interfering, the defect can be clearly seen. The inspection apparatus 1 uses an ultraviolet laser light source 36 that emits laser light in the ultraviolet region as a light source of ultraviolet light. Therefore, in the above inspection device 1,
Even a defect such as a scratch, which has no color information and consists only of irregularities, can be clearly detected. That is, in the inspection apparatus 1, the halogen lamp 3
Phase information, which is difficult to detect with visible light (incoherent light) from 2, can be easily detected using the ultraviolet laser (coherent light) from the ultraviolet laser light source 36.

Next, an example of a procedure for inspecting a semiconductor wafer by the inspection apparatus 1 will be described with reference to a flowchart of FIG. Note that the flowchart of FIG. 6 shows a procedure of a process after the semiconductor wafer to be inspected is set on the inspection stage 14. Further, the flowchart shown in FIG. 6 shows an example of a procedure when the defect is inspected by the inspection apparatus 1 and classified when the position of the defect on the semiconductor wafer is known in advance. Here, it is assumed that a number of similar device patterns are formed on a semiconductor wafer, and the detection and classification of defects are performed by using an image of a defective area (a defect image) and an image of another area (a reference image). ) Is taken and compared.

First, as shown in step S1-1, a defect position coordinate file is read into the control computer 61. Here, the defect position coordinate file is a file in which information relating to the position of the defect on the semiconductor wafer is described, and is created by measuring the position of the defect on the semiconductor wafer in advance by a defect detection device or the like. Then, here, the defect position coordinate file is read into the control computer 61.

Next, in step S1-2, the X stage 15 and the Y stage 16 are driven by the control computer 61 to move the semiconductor wafer to the defect position coordinates indicated by the defect position coordinate file. In the field of view of the objective lens 34 for visible light.

Next, in step S1-3, the visible light autofocus controller 35 is driven by the control computer 61 to perform automatic focus positioning of the visible light objective lens.

Next, in step S1-4, an image of the semiconductor wafer is captured by the visible light CCD camera 30, and the captured visible image is sent to the image processing computer 60. The visible image captured here is an image at the defect position coordinates indicated by the defect position coordinate file, that is, an image of a region where a defect is present (hereinafter, referred to as a defect image).

Next, in step S1-5, the X stage 15 and the Y stage 16 are driven by the control computer 61 to move the semiconductor wafer to the reference position coordinates, and the reference area of the semiconductor wafer is changed to the visible light objective lens. 3
4 so that it is within the field of view. Here, the reference region is a region other than the inspection target region of the semiconductor wafer, and is a region where a device pattern similar to the device pattern in the inspection target region of the semiconductor wafer is formed.

Next, in step S1-6, the visible light autofocus control unit 35 is driven by the control computer 61 to perform automatic focus positioning of the visible light objective lens.

Next, in step S1-7, an image of the semiconductor wafer is captured by the visible light CCD camera 30, and the captured visible image is sent to the image processing computer 60. Note that the visible image captured here is an image of a region where a device pattern similar to the device pattern in the inspection target region of the semiconductor wafer is formed (hereinafter, referred to as a reference image).

Next, at step S1-8, the image processing computer 60 compares the defect image captured at step S1-4 with the reference image captured at step S1-7, and detects a defect from the defect image. I do. If a defect is detected, the process proceeds to step S1-9. If a defect is not detected, the process proceeds to step S1-9.
Proceed to 11.

In step S1-9, the image processing computer 60 checks what the detected defect is and performs classification. If the defect can be classified, the process proceeds to step S1-10. If the defect cannot be classified, the process proceeds to step S1-11.

In step S1-10, the result of defect classification is stored. Here, the defect classification result is stored in, for example, a storage device connected to the image processing computer 60 or the control computer 61. Note that the defect classification result may be transferred to another computer connected to the image processing computer 60 or the control computer 61 via a network, and may be stored.

When the processing in step S1-10 is completed, it means that the classification of the defects in the semiconductor wafer has been completed, and the processing is completed. However, when there are a plurality of defects on the semiconductor wafer, the process may return to step S1-2 to detect and classify other defects.

On the other hand, if the defect cannot be detected in step S1-8, or if the defect cannot be classified in step S1-9, the process proceeds to step S1-11 and the subsequent steps. Defect detection and classification are performed by imaging at a resolution.

In that case, first, in step S1-11, the X stage 15 is controlled by the control computer 61.
Then, the Y stage 16 is driven to move the semiconductor wafer to the defect position coordinates indicated by the defect position coordinate file, so that the inspection target area of the semiconductor wafer falls within the field of view of the ultraviolet light objective lens 38.

Next, in step S1-12, the control computer 61 drives the ultraviolet auto-focus control section 39 to perform automatic focus positioning of the ultraviolet light objective lens.

Next, in step S1-13, an image of the semiconductor wafer is taken by the ultraviolet CCD camera 31, and the taken ultraviolet image is sent to the image processing computer 60. The ultraviolet image captured here is an image at the defect position coordinates indicated by the defect position coordinate file, that is, a defect image. In addition, imaging of the defect image here is performed with higher resolution than imaging using visible light, using ultraviolet light that is light having a shorter wavelength than visible light.

Next, in step S1-14, the control computer 61 drives the X stage 15 and the Y stage 16 to move the semiconductor wafer to the reference position coordinates. 38. Here, the reference area is
This is an area other than the inspection target area of the semiconductor wafer, in which a device pattern similar to the device pattern in the inspection target area of the semiconductor wafer is formed.

Next, in step S1-15, the control computer 61 drives the ultraviolet auto focus control section 39 to perform automatic focus positioning of the ultraviolet light objective lens.

Next, in step S1-16, an image of the semiconductor wafer is taken by the ultraviolet CCD camera 31, and the taken ultraviolet image is sent to the image processing computer 60. The ultraviolet image captured here is an image of a region where a device pattern similar to the device pattern in the inspection target region of the semiconductor wafer is formed, that is, a reference image. The imaging of the reference image here is performed at a higher resolution than when visible light is used by using ultraviolet light that is light having a shorter wavelength than visible light.

Next, in step S1-17, the image processing computer 60 compares the defect image captured in step S1-13 with the reference image captured in step S1-16, and detects a defect from the defect image. I do.
If a defect can be detected, step S1-1
Proceeding to step S8, if no defect is detected, proceeding to step S1-19.

In step S1-18, the image processing computer 60 checks what the detected defect is and performs classification. If the defect classification has been completed, the process proceeds to step S1-10, and the defect classification result is stored as described above. On the other hand, if the defect cannot be classified, the process proceeds to step S1-19.

In step S1-19, information indicating that the defect cannot be classified is stored. Here, information indicating that the defect cannot be classified is stored, for example, in a storage device connected to the image processing computer 60 or the control computer 61. Note that this information may be transferred to another computer connected to the image processing computer 60 or the control computer 61 via a network and stored.

According to the above-described procedure, first, an image picked up by the visible light CCD camera 30 is processed and analyzed to inspect the semiconductor wafer at a low resolution, and to detect a defect by visible light, When classification was not possible,
Next, the semiconductor wafer is inspected with high resolution by processing and analyzing the image captured by the ultraviolet CCD camera 31.

Here, a method of detecting a defect from a reference image and a defect image picked up by the CCD cameras 30 and 31 will be described with reference to FIG.

FIG. 7A shows an example of a reference area image in which a device pattern similar to the device pattern in the inspection target area is formed, that is, an example of the reference image. FIG. 7B shows an example of an image of a region to be inspected which is assumed to have a defect, that is, an example of a defect image.

When a defect is detected from such a reference image and a defect image, a device pattern is extracted from the reference image as shown in FIG. 7C based on color information, density information, and the like. Further, a difference image is obtained from the reference image and the defect image, and a portion having a large difference is extracted as a defect as shown in FIG.

Then, as shown in FIG.
An image obtained by superimposing the image of the device pattern extraction result shown in FIG. 7C and the image of the defect extraction result shown in FIG. 7D is obtained, and the rate at which the defect exists in the device pattern is determined. It is extracted as a feature value.

By the above-described method, the CCD camera 3
The image processing computer 60 processes and analyzes the reference image and the defect image captured by 0 and 31 to detect a defect and inspect a semiconductor wafer.

As described above, the inspection apparatus 1 first inspects the semiconductor wafer at a low resolution by processing and analyzing the image picked up by the visible light CCD camera 30, and inspects the defect by visible light. If the detection and classification cannot be performed, the semiconductor wafer is inspected at a high resolution by processing and analyzing the image captured by the ultraviolet CCD camera 31. It is possible to detect and classify finer defects as compared to the case of detecting and classifying defects using only visible light.

However, when imaging with low resolution using visible light, the area that can be imaged at a time is wider. If the defect is sufficiently large, inspection of the semiconductor wafer with low resolution using visible light is possible. Is more efficient. Therefore,
Rather than using ultraviolet light to inspect and classify defects from the beginning, as described above, inspecting and classifying defects using visible light first enables more efficient semiconductor wafers. Inspection can be performed.

By the way, in this inspection apparatus 1, as described above, the X-stage 15
And the Y stage 16, the semiconductor wafer to be inspected is moved in the horizontal direction, and the device pattern to be inspected is guided to a predetermined inspection position.

Here, the X stage 15 and the Y stage 1
8 is a plan view schematically showing the device 6 from the upper side of the apparatus main body 10 in FIG.
Shown in

The X stage 15 and the Y stage 16 include
As shown in FIG. 8, an X stage moving means and a Y stage moving means for moving the X stage 15 and the Y stage 16 in directions orthogonal to each other are provided, and the semiconductor wafer 70 is moved to a predetermined position. It has been made to be moved.

More specifically, as shown in FIGS. 8 and 9, the X stage 15 serves as an X stage moving means, which is a pair of first rail mechanisms disposed on the stone surface plate 13a of the anti-vibration table 13. 71, 72 and the pair of first rail mechanisms 7
And a first drive mechanism 73 arranged in parallel between the first drive mechanism 72 and the first drive mechanism 72. FIG. 9 shows the apparatus main body 10 as indicated by an arrow A1 in FIG.
It is the principal part side view seen from the direction typically.

As shown in FIG. 9, the pair of first rail mechanisms 71 and 72 support the X stage 15 while
The first rail portions 71a, 72a supported on the stone surface plate 13a for sliding in the direction of the middle arrow C.
And a first slider portion 7 fixed to the X stage 15 side.
1b and 72b are configured to slide while engaging with each other.

On the other hand, the first drive mechanism 73 is for driving and operating the X stage 15 supported by the first rail mechanisms 71 and 72. A first ball screw 74 attached to the lower surface of the stage 15 and a first drive screwed with the first ball screw 74 and rotatably supported by a pair of first bearing portions 75a and 75b. A shaft 76 and a first servomotor 78 connected to one end of the first drive shaft 76 via a first coupling 77 are provided.

The first ball screw 74 is connected to the X stage 15
8 are attached at both ends in the direction of arrow C in FIG. The first ball screw 74 is screwed to the first drive shaft 76 via a ball.
When the drive shaft 76 is driven to rotate, the first drive shaft 7
6 (along arrow C in FIG. 8).

On the other hand, both ends of the first drive shaft 76 are rotatably supported by a pair of first bearings 75a and 75b, and the pair of first bearings 75a and 75b.
The first ball screw 74 is moved while being screwed between b. Note that a pair of first bearing portions 75a, 75
b is, for example, the first bearing portion 7 provided on one end side.
5a is an angular bearing, and the first bearing 75b provided on the other end is a radial bearing.

The first servomotor 78 drives the first drive shaft 76 to rotate, and the first drive shaft 76 is connected to the first bearing 75 a side end of the first drive shaft 76 via a first coupling 77. Connected. Also, the first servo motor 78
Is connected to the above-described stage control interface 61c.
It will operate based on the control signal from c.

In the first drive mechanism 73, when the first servo motor 78 drives the first drive shaft 76 to rotate,
The first ball screw 74 moves along the axial direction of the first drive shaft 76 (the direction of arrow C in FIG. 8). And this first
X stage 15 attached to ball screw 74 of
While being supported by the first rail mechanisms 71 and 72, it horizontally moves in the direction of arrow C in FIG.

Similarly, the Y stage 16 is shown in FIGS.
0, a pair of second rail mechanisms 79, 8 disposed on the X stage 15 as Y stage moving means.
0 and a second drive mechanism 81 provided in parallel between the pair of second rail mechanisms 79 and 80. In addition,
FIG. 10 is a side view of a main part schematically showing the apparatus main body 10 from the direction of arrow A2 in FIG.

As shown in FIG. 10, the pair of second rail mechanisms 79, 80 are for sliding in the direction of arrow D in FIG.
Second rail portions 79a, 8 supported on stage 15
0a and the second slider portions 79b and 80b fixed to the Y stage 16 slide while engaging with each other.

On the other hand, the second drive mechanism 81 is for driving and operating the Y stage 16 supported by the second rail mechanisms 79 and 80. A second ball screw 82 attached to the lower surface of the stage 16 and a second drive screwed with the first ball screw 82 and rotatably supported by a pair of second bearings 83a and 83b. A shaft 84 and a second servomotor 86 connected to one end of the second drive shaft 84 via a second coupling 85 are provided.

The second ball screw 82 is connected to the Y stage 16
8 are attached at both ends in the direction of arrow D in FIG. The second ball screw 82 is screwed to the second drive shaft 82 via a ball.
When the drive shaft 84 is driven to rotate, it is configured to move along the axial direction of the drive shaft 84 (the direction of arrow D in FIG. 8).

On the other hand, both ends of the second drive shaft 84 are rotatably supported by a pair of second bearings 83a and 83b, and the pair of second bearings 83a and 83b.
The configuration is such that the second ball screw 82 moves while screwing between b. Note that the pair of second bearing portions 83a, 83
b is, for example, the second bearing portion 8 provided on one end side.
3a is an angular bearing, and the second bearing 83b provided at the other end is a radial bearing.

The second servomotor 86 drives the second drive shaft 84 to rotate. The second servomotor 86 is connected to the end of the second drive shaft 84 on the side of the second bearing 83 a via a coupling 85. ing. The second servo motor 86 is connected to the above-described stage control interface 61c, and operates based on a control signal from the stage control interface 61c.

In the second drive mechanism 81, when the second servo motor 86 drives the second drive shaft 84 to rotate,
The second ball screw 82 moves along the axial direction of the second drive shaft 84 (the direction of arrow D in FIG. 8). And this second
Y stage 16 attached to ball screw 82 of
While being supported by the second rail mechanisms 79 and 80, it horizontally moves in the direction of arrow D in FIG.

Here, the X stage 15 and the Y stage 1
6 is connected to the control computer 61 disposed in the external unit 50 via the stage control interface 61c as described above. The X stage 15 and the Y stage 16 include a control computer 61.
Via the stage control interface 61c. The X stage 15 and the Y stage 16 guide the semiconductor wafer to a predetermined inspection position based on the control signal.

More specifically, the first drive mechanism 73 of the X stage 15 and the second drive mechanism 81 of the Y stage 16 are driven and operated based on a control signal from the stage control interface 61c. Rail mechanism 7
The X stage 15 and the Y stage 16 supported by the first and second rail mechanisms 79 and 80 are moved to predetermined positions.

The X stage 15 and the Y stage 16 detect the positions of the X stage 15 and the Y stage 16 based on the detected signals in order to guide the semiconductor wafer 70 to a predetermined inspection position. And X
A so-called positioning servo for moving the stage 15 and the Y stage 16 to predetermined positions is performed.

However, in the conventional inspection apparatus, when such positioning servo is performed, the X stage 15
In addition, the Y stage 16 cannot be accurately positioned at a predetermined position, which may lead to a significant decrease in inspection capability.

Therefore, in the inspection apparatus 1, a sliding resistance is added to the first drive shaft 76 of the X stage 15 and the second drive shaft 84 of the Y stage 16, and the first drive shaft 73 By adjusting the sliding resistance applied to the second drive shaft 84, the X stage 15 and the Y stage 16 are accurately positioned at predetermined positions.

More specifically, as shown in FIGS. 8 to 10, the inspection apparatus 1 has the first drive shaft 76 at the end on the first bearing portion 75b side and the first drive shaft 76 at the end. A first sliding contact resistance adding means 87 for adjusting the sliding contact resistance in a freely adjustable manner.
And second sliding contact resistance adding means 88 for adjusting the sliding contact resistance to the second driving shaft 84 at the end of the second driving shaft 84 on the side of the second bearing portion 83b. Is provided.

In the following description, since the first sliding contact resistance adding means 87 and the second sliding contact resistance adding means 88 have the same configuration, the first sliding contact resistance adding means 87 is used.
And the second sliding resistance adding means 88 is connected to the second sliding resistance adding means 9.
0, and the first drive shaft 76 and the second drive shaft 84 will be described as the drive shaft 91.

As shown in FIG. 11, the sliding contact resistance adding means 90 includes a sliding contact member 92 slidingly contacting the outer peripheral surface of the drive shaft 91.
An adjusting mechanism 93 for adjusting the contact pressure of the sliding contact member 92 against the outer peripheral surface of the drive shaft 91; and a support member 94 for supporting the sliding contact member 92.

The sliding contact member 92 includes a sliding contact surface portion 95 that makes sliding contact with the outer peripheral surface of the drive shaft 91 over substantially the entire circumference, and the sliding contact surface portion 9.
5 and a plurality of grooves 9 for dividing the entire circumference of the sliding contact surface 95 at predetermined intervals.
7a and 97b. As a material of the sliding contact member 92, a material having characteristics such as elasticity, less wear, less generation of cutting powder, and stable friction resistance is preferable.
C nylon, POM and the like can be mentioned.

As shown in FIG. 12, the sliding contact surface portion 95 is a surface which is in sliding contact with the drive shaft 91 passing through the sliding contact member 92.
A part of the peripheral surface of the hole 98 penetrating the sliding contact member 92 is formed to protrude toward the drive shaft 91.

As shown in FIG. 11, the opening 96 is cut out from the upper surface of the sliding member 92 to the sliding surface 95 with a predetermined width.

The plurality of grooves 97a and 97b are
By dividing the sliding surface 5 at a predetermined interval, the divided sliding contact surface portion 95 uniformly contacts the outer peripheral surface of the drive shaft 91.

As shown in FIGS. 11 and 12, the adjusting mechanism 93 has a structure in which the upper portion divided by the opening 96 of the sliding contact member 92 is fastened from both sides by fastening bolts 100 via springs 99. Is done.

In the adjusting mechanism 93, the spring 99 presses the sliding contact member 92, and the spring 9 is adjusted by adjusting the tightening of the adjusting nut 100a of the fastening bolt 100.
The width of the opening 96 of the sliding contact member 92 can be changed by changing the pressure on the sliding contact member 92 of FIG. In the sliding contact member 92, the contact pressure of the sliding contact surface portion 95 on the outer peripheral surface of the drive shaft 91 can be changed by changing the width of the opening 96. Therefore, in this sliding contact resistance adding means 90, the contact pressure of the sliding contact member 92 against the outer peripheral surface of the drive shaft 91 can be freely adjusted by the adjusting mechanism 93.

The support member 94 is a long member.
A sliding contact member 92 is attached to a substantially central portion thereof with a screw 101. The support member 94 supports the sliding contact member 92, and both ends of the support member 94 are fixed on the stone platen 13 a or the X stage 15 by bolts 102.

When the X stage 15 and the Y stage 16 are operated to move to the predetermined positions, the sliding contact resistance adding means 90 configured as described above is used to rotate the driving shaft 91.
The sliding contact surface portion 95 of the sliding contact member 92 adds sliding contact resistance to the outer peripheral surface of the sliding contact member.

As a result, in the inspection apparatus 1, the X stage 15 and the Y stage 16 can be accurately positioned at predetermined positions.

Here, such sliding contact resistance adding means 90
Are measured with respect to the positioning servo between the inspection device 1 provided with the inspection device and the inspection device not provided with the sliding contact resistance adding means 90 as in the related art. Hereinafter, the measurement results are shown in FIG.
3 and FIG. 13 and 14, the horizontal axis indicates elapsed time, and the vertical axis indicates the amount of movement of the inspection stage 14.

As shown in FIG. 13, in the conventional inspection apparatus, it can be seen that fine vibration occurs on the inspection stage 14 and the inspection stage 14 is not accurately positioned. On the other hand, in this inspection apparatus 1, FIG.
As shown in FIG. 7, it can be seen that the inspection stage 14 does not move, and the inspection stage 14 is accurately positioned. Thus, in the inspection apparatus 1, the inspection stage 14 on which the semiconductor wafer 70 to be inspected is placed can be accurately positioned at a predetermined position.

The sliding contact resistance adding means 90 can arbitrarily adjust the contact pressure of the sliding member 92 against the outer peripheral surface of the drive shaft 91 by the adjusting mechanism 93. Can be easily adjusted.

Accordingly, in the inspection apparatus 1, when the X stage 15 and the Y stage 16 are moved to a predetermined position, the sliding contact member 92 adds a sliding contact resistance to the drive shaft 91 which is driven to rotate. By adjusting the sliding resistance applied to the drive shaft 91 by the adjusting mechanism 93, the inspection stage 14 on which the semiconductor wafer 70 is mounted can be accurately positioned at a predetermined position, and the inspection capability can be reduced. Significant improvement can be achieved.

In particular, since the inspection apparatus 1 inspects the semiconductor wafer 70 at a high resolution using ultraviolet light, it is not necessary to provide the sliding contact resistance adding means 90 on the drive shaft 90 for the inspection. This is very effective in accurately positioning the stage 14.

Further, in the inspection apparatus 1, as shown in FIG. 15, a radiating fin 103 may be provided as a radiating means for dissipating the frictional heat generated by the sliding resistance adding means 90. . This radiation fin 103
Is provided at a position sandwiching the sliding contact member 92 so as to cover the outer peripheral surface of the drive shaft 90. Thereby, the sliding contact member 92 can efficiently radiate frictional heat generated by the sliding contact surface portion 95 slidingly contacting the drive shaft 90,
It is possible to prevent the sliding resistance of the sliding contact surface portion 95 from being largely changed by the frictional heat. Therefore, in this inspection device 1, a stable sliding contact resistance can be added to the drive shaft 90.

In the sliding resistance adding means 90, the adjusting mechanism 93 is not necessarily limited to the above-described structure. For example, an air cylinder may be provided instead of the spring 99, and the sliding member 92 may be compressed by air pressure. The width of the opening 96 may be changed to adjust the contact pressure of the sliding contact member 92 against the outer peripheral surface of the drive shaft 91.

Further, in the sliding contact resistance adding means 90, an actuator may be provided in the adjusting mechanism 93 to control the adjustment of the contact pressure of the sliding member 92 against the outer peripheral surface of the drive shaft 91. Thus, when the drive shaft 91 is driven, no sliding contact resistance is added to the drive shaft 91 before the positioning servo is performed, or when the drive shaft 91 is stopped, the sliding contact resistance is strongly applied to the drive shaft 91. Can be performed.

In the above description, the inspection apparatus 1 to which the present invention is applied has been used for checking what the defect is in the semiconductor wafer. However, the use of the inspection apparatus 1 according to the present invention can be used for purposes other than the defect identification of the semiconductor wafer. That is, the inspection apparatus 1 according to the present invention can be used, for example, to inspect whether a device pattern formed on a semiconductor wafer is formed in an appropriate shape as a desired pattern. Further, the use of the inspection device 1 according to the present invention is not limited to inspection of a semiconductor wafer, and the inspection device 1 according to the present invention is widely applicable to inspection of fine patterns. It is also effective for inspection of flat panel displays on which various patterns are formed.

[0170]

As described above in detail, in the inspection apparatus according to the present invention, the sliding resistance is added to the drive shaft of the stage, and the sliding resistance added to the drive shaft is adjusted. The stage on which the object to be inspected is placed can be accurately positioned at a predetermined inspection target position, and the inspection capability can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the appearance of an inspection apparatus to which the present invention is applied.

FIG. 2 is a diagram showing a state in which an apparatus main body disposed inside a clean box of the inspection apparatus is viewed from a direction of an arrow A1 in FIG.

FIG. 3 is a plan view schematically showing an apparatus main body of the inspection apparatus.

FIG. 4 is a block diagram showing a configuration example of the inspection device.

FIG. 5 is a diagram showing a configuration example of an optical system of an optical unit of the inspection device.

FIG. 6 is a flowchart showing an example of a procedure when a semiconductor wafer is inspected by the inspection apparatus.

FIG. 7 is a diagram for explaining a method of detecting a defect from a reference image and a defect image.

FIG. 8 is a plan view schematically showing an X stage and a Y stage of the inspection apparatus from above the apparatus main body.

9 is a side view of a main part of the main body of the inspection apparatus schematically viewed from the direction of arrow A1 in FIG.

10 is a side view of a main part of the main body of the inspection apparatus schematically viewed from the direction of arrow A2 in FIG.

FIG. 11 is a diagram showing a configuration of a sliding resistance adding means.

FIG. 12 is a cross-sectional view showing a configuration of a sliding contact member.

FIG. 13 is a characteristic diagram showing a result obtained by measuring a positioning servo of the inspection apparatus.

FIG. 14 is a characteristic diagram showing a result of measuring a positioning servo of a conventional inspection device.

FIG. 15 is a plan view showing a configuration in which a radiating fin is provided on the sliding contact resistance adding means.

FIG. 16 is a diagram illustrating a positioning servo.

[Explanation of symbols]

Reference Signs List 1 inspection device, 2 clean unit, 3 clean box, 4 clean air unit, 5a, 5b blower, 10 device body, 14 inspection stage, 21 optical unit, 22 elevator, 23 transport robot, 24 pre-aligner, 30 for visible light CCD camera, 31 ultraviolet CCD camera, 32 halogen lamp, 33 visible light optical system, 34 visible light objective lens, 36 ultraviolet laser light source, 37 ultraviolet light optical system,
38 Objective lens for ultraviolet light, 50 External unit, 5
2, 53 display device, 54 input device, 60 image processing computer, 61 control computer, 70 semiconductor wafer, 71, 72 first rail mechanism, 73 first drive mechanism, 74 first ball screw, 76 1 drive shaft, 78 first servomotor, 79, 80 second
Rail mechanism, 81 second drive mechanism, 82 second ball screw, 84 second drive shaft, 86 second servomotor, 87 first sliding contact resistance adding means, 88 second sliding contact resistance addition Means, 90 sliding contact resistance adding means, 91 drive shaft, 92 sliding contact member, 93 adjusting mechanism, 94 support member,
95 sliding contact surface part, 96 opening part, 97a, 97b groove part, 99 spring, 100 fastening bolt, 100a adjusting nut, 103 radiation fin

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Isao Kayama, Inventor 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Masayuki Morita 6-35, Kita-Shinagawa, Shinagawa-ku, Tokyo No. Sony Corporation (72) Inventor Tsutomu Sakashita 3-9-17 Nishigotanda, Shinagawa-ku, Tokyo Sony Precision Technology Inc. In-house F-term (reference) 2F078 CA01 CA08 CB02 CB05 CB06 CB09 CB12 CB18 CC03 CC11 CC15 2G051 AA51 AB02 AC21 BA05 BA08 BA10 CA04 DA03 DA08 DA20 EA08 EA11 EC01 ED11 FA01 4M106 AA01 BA04 BA07 CA39 CA41 DB04 DB07 DB08 DB12 DB13 DB16 DJ04 DJ05 DJ06 DJ07 DJ20 DJ23 DJ24 5F031 CA02 GA43 HA13 JA08 KA08 JA50

Claims (7)

[Claims] 1. A stage on which an object to be inspected is mounted, stage moving means for moving the stage on which the object to be inspected is mounted to a predetermined inspection object position while controlling the stage, and driving of the stage moving means An inspection apparatus comprising: a sliding contact resistance adding unit that adjustably adds a sliding contact resistance to a shaft. 2. A sliding contact member for slidingly contacting the peripheral surface of the drive shaft, and a sliding contact resistance adjusting unit for adjusting a contact pressure of the sliding contact member against the peripheral surface of the drive shaft. The inspection device according to claim 1, comprising: 3. The sliding contact member includes: a sliding contact surface that slides over substantially the entire circumference of the drive shaft; an opening provided by cutting out a part of the sliding contact surface; An elastic member having a plurality of grooves that divide the entire periphery of the sliding contact surface at a predetermined interval; and the sliding contact resistance adjusting means changes a width of an opening of the sliding contact member to thereby control the drive shaft. 3. The inspection apparatus according to claim 2, wherein the contact pressure on the peripheral surface of the test piece is adjusted. 4. The inspection apparatus according to claim 3, wherein said sliding contact resistance adjusting means changes a width of said opening of said sliding member by a spring pressure. 5. The inspection apparatus according to claim 2, further comprising a sliding contact resistance control means for controlling said sliding contact resistance adjusting means. 6. An inspection apparatus according to claim 1, further comprising a heat radiating means for dissipating heat generated by said sliding contact resistance adding means. 7. Irradiating the inspection object with ultraviolet light,
The inspection apparatus according to claim 1, wherein the inspection object is inspected by detecting the reflected light or the transmitted light.