JP4632471B2 - Inspection device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
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]
[Prior 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. A semiconductor device in which such a defect has occurred becomes a defective device and reduces the yield.
[0003]
Therefore, in order to stabilize the yield of the production line at a high level, it is necessary to detect defects caused by dust or scratches at an early stage, identify the cause, and take effective measures for the production equipment and production process. preferable.
[0004]
Therefore, when a defect is found, an inspection apparatus is used to investigate what the defect is and classify it to identify the facility or process that caused the defect. Here, the inspection apparatus that examines what the defect is is like an optical microscope, and the defect is magnified to identify what the defect is.
[0005]
[Problems to be solved by the invention]
By the way, in an inspection apparatus that performs such inspection, an image of a semiconductor wafer on which a predetermined device pattern is formed is captured, and the captured image is processed and analyzed to inspect the semiconductor wafer. .
[0006]
Specifically, when taking an image of the semiconductor wafer, the semiconductor wafer is illuminated with illumination light, the image of the illuminated semiconductor wafer is magnified by an objective lens, and the magnified image is CCD (charge-coupled device). ) Take an image with the camera. Then, by processing and analyzing the image captured by the CCD camera, the semiconductor wafer is inspected, and defects are detected and classified.
[0007]
However, in such an inspection apparatus, when a CCD camera is installed inside an optical unit for taking an image of a semiconductor wafer, due to an external load or vibration transmitted to the wiring routed to the CCD camera, etc. In some cases, the CCD camera is displaced, vibrated, or the like, and a clear image of the inspection object cannot be captured.
[0008]
For this reason, the inspection apparatus cannot properly detect and classify defects in the device pattern formed on the semiconductor wafer, which may cause a significant decrease in inspection capability.
[0009]
In particular, device patterns formed on semiconductor wafers are becoming increasingly finer as semiconductor devices are highly integrated, and even if a CCD camera is slightly misaligned, the device pattern formed on the semiconductor wafer. Cannot be captured as a clear image, and it becomes difficult to appropriately detect and classify defects.
[0010]
Therefore, the present invention has been proposed in view of such a conventional situation, and an object thereof is to provide an inspection apparatus capable of capturing an image of an inspection object in a more stable state.
[0011]
[Means for Solving the Problems]
An inspection apparatus according to the present invention that achieves this object is placed on a support base in an inspection apparatus that inspects an inspection object by taking an image of the inspection object and processing and analyzing the image. A substantially square-shaped imaging means and a front surface on which an image of the inspection object of the imaging means is captured Fixed to And a first support member fixed on the support base, a second support member fixed on the support base and one side surface of the imaging means, and an upper surface of the imaging means Fixed to As well as ,Up A third support member fixed to the second support member, and the imaging means is a CCD camera for visible light and a CCD camera for ultraviolet light, and takes an image of the object to be inspected illuminated by visible light Then, an image of the inspection object illuminated with ultraviolet light is captured.
[0012]
As described above, in the inspection apparatus according to the present invention, since the imaging means is fixed by the first support member, the second support member, and the third support member, the imaging means is more stable on the support base. Can be installed.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0014]
The appearance of an inspection apparatus to which the present invention is applied is shown in FIG. This inspection apparatus 1 is for inspecting a semiconductor wafer on which a predetermined device pattern is formed, and when a defect is found in a device pattern formed on a semiconductor wafer, what is the defect? It classifies by examining.
[0015]
As shown in FIG. 1, the inspection apparatus 1 includes a clean unit 2 for keeping the 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 into a hollow box shape, and a clean air unit 4 integrally provided on the upper portion of the clean box 3.
[0016]
The clean box 3 is provided with a window portion 3a at a predetermined location so that an inspector can visually recognize the inside of the clean box 3 from the window portion 3a.
[0017]
The clean air unit 4 is for supplying clean air into the clean box 3, and includes two blowers 5a and 5b respectively disposed at different positions on the upper portion of the clean box 3, and these blowers 5a and 5b. And an air filter (not shown) disposed between the clean box 3 and the clean box 3. The air filter is, for example, a high-performance air filter such as a HEPA filter (High Efficiency Particulate Air Filter) or a ULPA filter (Ultra Low Penetration Air Filter). The clean air unit 4 is configured to remove dust and the like in the air blown by the blowers 5a and 5b with a high-performance air filter and supply the clean box 3 as clean air.
[0018]
Moreover, in this clean unit 2, the air flow in the clean box 3 is controlled by individually controlling the air volume of clean air supplied from the clean air unit 4 into the clean box 3 for each of the two blowers 5a and 5b. It is possible to control appropriately. 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 in accordance with the size and shape of the clean box 3, and includes three or more blowers. It may be configured. In this case, in the inspection apparatus 1, the air volume of clean air supplied from the clean air unit 4 into the clean box 3 is individually controlled for each blower.
[0019]
The clean unit 2 has a structure in which the clean box 3 is supported on the floor board by the support legs 6 and the lower end thereof is opened. 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. In addition, an opening region 3 b is provided at a predetermined location on the side surface of the clean box 3, and air supplied from the clean air unit 4 into the clean box 3 is provided on the side surface of the clean box 3. Also, the air is discharged from the open area 3b.
[0020]
As described above, the clean unit 2 constantly supplies clean air from the clean air unit 4 into the clean box 3 and discharges air circulated in the clean box 3 as an air current to the outside of the clean box 3. Let As a result, dust or the like generated in the clean box 3 is discharged to the outside of the clean box 3 together with this air, and the internal environment of the clean box 3 is kept at a very high cleanness of, for example, about class 1. . Further, in the clean box 3, the internal atmospheric pressure is always kept at a positive pressure in order to prevent air including dust from entering the inside from the outside.
[0021]
In this inspection apparatus 1, as shown in FIG. 2, an apparatus main body 10 is accommodated in a clean box 3, and a semiconductor in which a predetermined device pattern is formed by the apparatus main body 10 in the clean box 3. The wafer is inspected. Here, the semiconductor wafer to be inspected is transferred into a predetermined sealed container 7 and transferred to the inside of the clean box 3 through the container 7. 2 is a side view showing a state in which the apparatus main body 10 arranged in the clean box 3 is viewed from the direction of arrow A in FIG.
[0022]
The container 7 includes a bottom portion 7a, a cassette 7b fixed to the bottom portion 7a, and a cover 7c that is detachably engaged with the bottom portion 7a and covers the cassette 7b. The semiconductor wafers to be inspected are mounted on the cassette 7b so that a plurality of semiconductor wafers are overlapped with each other at a predetermined interval, and are sealed by the bottom 7a and the cover 7c.
[0023]
When inspecting a semiconductor wafer, first, the container 7 in which the semiconductor wafer is placed is installed in a container installation space 8 provided at a predetermined position of the clean box 3. The container installation space 8 is arranged such that the upper surface of a lift 22a of an elevator 22 to be described later faces the outside of the clean box 3, and the bottom 7a of the container 7 is positioned on the lift 22a of the elevator 22. As shown, it is installed in the container installation space 8.
[0024]
When the container 7 is installed in the container installation space 8, the engagement between the bottom 7a of the container 7 and the cover 7c is released. 2 is moved down in the direction of arrow B in FIG. 2, the bottom 7a and the cassette 7b of the container 7 are separated from the cover 7c and moved into the clean box 3. As a result, the semiconductor wafer that is the object to be inspected is transferred into the clean box 3 without being exposed to the outside air.
[0025]
When the semiconductor wafer is transferred into the clean box 3, a semiconductor robot to be inspected is taken out from the cassette 7b and inspected by a transfer robot 23 described later.
[0026]
As described above, since the inspection apparatus 1 inspects the semiconductor wafer inside the clean box 3 maintained at a high degree of cleanness, dust or the like adheres to the semiconductor wafer at the time of inspection. Inconveniences such as inhibition 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 through the container 7. If only the inside of the container 7 is kept clean enough, 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 apparatus 1 is installed. .
[0027]
Thus, by increasing only the degree of cleanliness at a necessary place locally, it is possible to achieve a high degree of cleanness and to significantly reduce the cost for realizing a clean environment. As a mechanical interface between the sealed container 7 and the clean box 3, a so-called SMIF (standard mechanical interface) is suitable. In this case, a so-called SMIF-POD is used as the sealed container 7. .
[0028]
In addition, 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 the floor board by support legs 51. In the external unit 50, a display device 52 for displaying an image obtained by imaging a semiconductor wafer, a display device 53 for displaying various conditions at the time of inspection, an instruction input to the device main body 10 and the like are performed. The input device 54 and the like are also arranged. An inspector who inspects the semiconductor wafer inputs necessary instructions from the input device 54 disposed in the external unit 50 while looking at the display devices 52 and 53 disposed in the external unit 50, and inspects the semiconductor wafer. I do.
[0029]
Next, the apparatus main body 10 disposed in the clean box 3 will be described in detail.
[0030]
The apparatus main body 10 includes a support base 11 as shown in FIG. The support base 11 is a base for supporting each mechanism of the apparatus main body 10. A support leg 12 is attached to the bottom of the support base 11, and each mechanism provided on the support base 11 and the support base 11 is supported on the floor plate independently of the clean box 3 by the support leg 12. It has a structure.
[0031]
An inspection stage 14 on which a semiconductor wafer to be inspected is placed is provided on the support table 11 via a vibration isolation table 13.
[0032]
The vibration isolation table 13 is for suppressing vibration from the floor, vibration generated when the inspection stage 14 is moved, and the stone surface plate 13a on which the inspection stage 14 is installed. And a plurality of movable legs 13b that support the surface plate 13a. When the vibration is generated, the vibration isolation table 13 detects the vibration to drive the movable leg 13b, and the vibration of the stone surface plate 13a and the inspection stage 14 installed on the stone surface plate 13a. Will be canceled promptly.
[0033]
Since this inspection apparatus 1 inspects a semiconductor wafer on which a fine device pattern is formed, even a slight vibration may be an obstacle to the inspection. In particular, since this inspection apparatus 1 performs inspection with high resolution using ultraviolet light, the influence of vibration is likely to appear greatly. Therefore, in this inspection apparatus 1, by installing the inspection stage 14 on the vibration isolation table 13, even if a slight vibration occurs in the inspection stage 14, this vibration is quickly canceled and the vibration is reduced. By suppressing the influence, the inspection capability when performing inspection with high resolution using ultraviolet light is improved.
[0034]
In order to stably install the inspection stage 14 on the vibration isolation table 13, it is desirable that the center of gravity of the vibration isolation table 13 is at a position that is somewhat low. Therefore, in the inspection apparatus 1, a notch 13c is provided at the lower end of the stone surface plate 13a, and the movable leg 13b supports the stone surface plate 13a at the notch 13c so that the vibration isolation table 13 is provided. The center of gravity is lowered.
[0035]
Note that vibrations and the like generated when the inspection stage 14 is moved can be predicted to some extent in advance. If such vibration is predicted in advance and the vibration isolation table 13 is operated, vibration generated in the inspection stage 14 can be prevented in advance. Therefore, it is desirable that the inspection apparatus 1 operate the vibration isolation table 13 by predicting in advance vibrations or the like generated when the inspection stage 14 is moved.
[0036]
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 moving the semiconductor wafer to a predetermined inspection target position.
[0037]
Specifically, the inspection stage 14 includes an X stage 15 installed on the vibration isolation table 13, a Y stage 16 installed on the X stage 15, and 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.
[0038]
The X stage 15 and the Y stage 16 are stages that move in the horizontal direction, and the X stage 15 and the Y stage 16 move the semiconductor wafers to be inspected in directions orthogonal to each other, thereby changing the device pattern to be inspected. It leads to a predetermined inspection position.
[0039]
The θ stage 17 is a so-called rotation stage and is for rotating the 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 with respect to the screen.
[0040]
The Z stage 18 is a stage that moves in the vertical direction, and is for adjusting the height of the stage. During the inspection of the semiconductor wafer, the stage height is adjusted by the Z stage 18 so that the inspection surface of the semiconductor wafer has an appropriate height.
[0041]
The suction plate 19 is for sucking and fixing a 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 sucked by the suction plate 18 to suppress unnecessary movement.
[0042]
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 capturing an image of a semiconductor wafer during inspection of the semiconductor wafer. The optical unit 21 has a function of capturing an image of the semiconductor wafer to be inspected with low resolution using visible light, and an image of the semiconductor wafer to be inspected with high resolution using ultraviolet light. It has the function to perform.
[0043]
Further, as shown in FIGS. 2 and 3, an elevator 22 is provided on the support base 11 to take out a cassette 7 b mounted with a semiconductor wafer as an inspection object from the container 7 and move it into the clean box 3. ing. Further, as shown in FIG. 3, on the support base 11, a transfer robot 23 for transferring the semiconductor wafer, and centering and phase out before placing the semiconductor wafer on the inspection stage 14. A pre-aligner 24 is provided. FIG. 3 is a plan view schematically showing the apparatus main body 10 disposed in the clean box 3.
[0044]
The elevator 22 has a lifting platform 22a that is moved up and down. The container 7 is installed in the container installation space 8 of the clean box 3, and the engagement between the bottom 7a of the container 7 and the cover 7c is released. When the lifting platform 22a is lowered, the bottom 7a of the container 7 and the cassette 7b fixed thereto are moved into the clean box 3.
[0045]
The transfer robot 23 has an operation arm 23b provided with a suction mechanism 23a at the tip, and moves the operation arm 23b to suck the semiconductor wafer by the suction mechanism 23a provided at the tip. However, the semiconductor wafer is transported in the clean box 3.
[0046]
The pre-aligner 24 performs phase alignment and center alignment of the semiconductor wafer with reference to an orientation flat and a notch formed in advance on the semiconductor wafer. The inspection apparatus 1 improves the inspection efficiency by performing phase alignment and the like by the pre-aligner 24 before placing the semiconductor wafer on the inspection stage 14.
[0047]
When installing the semiconductor wafer on the inspection stage 14, first, the bottom portion 7 a and the cassette 7 b of the container 7 are moved into the clean box 3 by the elevator 22. Then, a semiconductor wafer to be inspected is selected from a plurality of semiconductor wafers mounted on the cassette 7b, and the selected semiconductor wafer is taken out from the cassette 7b by the transfer robot 23.
[0048]
The semiconductor wafer taken out from the cassette 7 b is transferred to the pre-aligner 24 by the transfer robot 23. The semiconductor wafer transferred to the pre-aligner 24 is phased and centered by the pre-aligner 24. Then, the phase-adjusted and center-adjusted semiconductor wafer is transferred to the inspection stage 14 by the transfer robot 23 and placed on the suction plate 19 for inspection.
[0049]
When the semiconductor wafer to be inspected is transferred to the inspection stage 14, the next semiconductor wafer to be inspected is taken out from the cassette 7 b by the transfer robot 23 and transferred to the pre-aligner 24. Then, while the semiconductor wafer previously transported to the inspection stage 14 is being inspected, the semiconductor wafer to be inspected next is phased out and centered out. Then, when the inspection of the semiconductor wafer previously transferred to the inspection stage 14 is completed, the semiconductor wafer to be inspected next is quickly transferred to the inspection stage 14.
[0050]
In the inspection apparatus 1, as described above, before the semiconductor wafer to be inspected is transferred to the inspection stage 14, the phase alignment and centering are performed in advance by the pre-aligner 24, so that the semiconductor wafer of the inspection stage 14 is aligned. The time required for positioning can be shortened. Further, in the inspection apparatus 1, the semiconductor wafer to be inspected next is taken out from the cassette 7 b by using the time during which the semiconductor wafer previously transported to the inspection stage 14 is inspected, and the phase alignment by the pre-aligner 24 is performed. By performing the centering operation, the overall time can be shortened and the inspection can be performed efficiently.
[0051]
By the way, in this inspection apparatus 1, as shown in FIG. 3, the elevator 22, the transfer robot 23, and the pre-aligner 24 are installed on the support base 11 so as to be aligned on a straight line. The respective installation positions are determined so that the distance L1 between the elevator 22 and the transport robot 23 and the distance L2 between the transport robot 23 and the pre-aligner 24 are substantially equal. Further, the inspection stage 14 is arranged in a direction substantially orthogonal to the direction in which the elevator 22 and the pre-aligner 24 are arranged as viewed from the transfer robot 23.
[0052]
Since the inspection apparatus 1 is arranged as described above, the inspection apparatus 1 can quickly and accurately carry a semiconductor wafer as an inspection object.
[0053]
That is, in this inspection apparatus 1, since the distance L1 between the elevator 22 and the transfer robot 23 and the distance L2 between the transfer robot 23 and the pre-aligner 24 are substantially equal, the transfer robot The semiconductor wafer taken out from the cassette 7b can be transferred to the pre-aligner 24 without changing the length of the arm 23b. Therefore, in this inspection apparatus 1, since an error or the like that occurs when the length of the arm 23b of the transfer robot 23 is changed does not become a problem, 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 from the cassette 7b to the pre-aligner 24 only by linear movement. . Therefore, in this inspection apparatus 1, the operation of transporting the semiconductor wafer to the pre-aligner 24 can be performed very accurately and quickly.
[0054]
Furthermore, in this inspection apparatus 1, since the inspection stage 14 is positioned in a direction substantially orthogonal to the direction in which the elevators 22 and the pre-aligner 24 are arranged as viewed from the transfer robot 23, the transfer robot The semiconductor wafer 23 can be transported to the inspection stage 14 by the 23 moving linearly. Therefore, in this inspection apparatus 1, the operation of transporting the semiconductor wafer to the inspection stage 14 can be performed very accurately and quickly. In particular, since the inspection apparatus 1 inspects a semiconductor wafer on which a fine device pattern is formed, it is necessary to carry and position the semiconductor wafer as an inspection object very accurately. Is very effective.
[0055]
In the inspection apparatus 1, tires 25 are provided at the bottoms of the clean box 3, the support 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 the inspection apparatus 1 is fixed, as shown in FIGS. 1 and 2, the support legs 6, 12, 51 are put on the floor and the tire 25 is left floating.
[0056]
Next, the inspection apparatus 1 will be described in more detail with reference to the block diagram of FIG.
[0057]
As shown in FIG. 4, the external unit 50 of the inspection apparatus 1 has an image processing computer 60 to which a display device 52 and an input device 54a are connected, and a control computer 61 to which a display device 53 and an input device 54b are connected. And are arranged. In FIG. 1 described above, the input device 54 a connected to the image processing computer 60 and the input device 54 b connected to the control computer 61 are collectively shown as the input device 54.
[0058]
The image processing computer 60 is a computer that captures and processes an image of a semiconductor wafer taken by CCD (charge-coupled device) cameras 30 and 31 installed in the optical unit 21 when inspecting the semiconductor wafer. . That is, the inspection apparatus 1 inspects a semiconductor wafer by processing and analyzing an image of the semiconductor wafer taken by the CCD cameras 30 and 31 installed in the optical unit 21 by the image processing computer 60. Do.
[0059]
The input device 54a connected to the image processing computer 60 is for inputting instructions necessary for analyzing the images taken from the CCD cameras 30 and 31 to the image processing computer 60. For example, it consists of 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 taken from the CCD cameras 30 and 31, and is composed of, for example, a CRT display or a liquid crystal display.
[0060]
The control computer 61 is a computer for controlling the inspection stage 14, the elevator 22, the transfer robot 23 and the pre-aligner 24, each device inside the optical unit 21, and the like when inspecting a semiconductor wafer. That is, the inspection apparatus 1 controls the control computer so that when the semiconductor wafer is inspected, an image of the semiconductor wafer to be inspected is taken by the CCD cameras 30 and 31 installed in the optical unit 21. 61 controls the inspection stage 14, the elevator 22, the transfer robot 23 and the pre-aligner 24, and the devices inside the optical unit 21.
[0061]
Further, the control computer 61 has a function of controlling the blowers 5 a and 5 b of the clean air unit 4. That is, the inspection device 1 always supplies clean air into the clean box 3 when the semiconductor computer is inspected by controlling the blowers 5a and 5b of the clean air unit 4 by the control computer 61. Further, the airflow in the clean box 3 can be controlled.
[0062]
The input device 54b connected to the control computer 61 includes the inspection stage 14, the elevator 22, the transfer robot 23 and the pre-aligner 24, the devices inside the optical unit 21, and the blowers 5a and 5b of the clean air unit 4. Are input to the control computer 61, and include, for example, a pointing device such as a mouse, a keyboard, and the like. The display device 53 connected to the control computer 61 is for displaying various conditions at the time of inspecting the semiconductor wafer, and is composed of, for example, a CRT display or a liquid crystal display.
[0063]
The image processing computer 60 and the control computer 61 can exchange data with each other by a memory link mechanism. In other words, the image processing computer 60 and the control computer 61 are connected to each other via the memory link interfaces 60a and 61a provided in each, and the image processing computer 60 and the control computer 61 are mutually connected. Data exchange is possible.
[0064]
On the other hand, inside the clean box 3 of the inspection apparatus 1, as a mechanism for taking out the semiconductor wafer that has been carried in a sealed container 7 from the cassette 7b of the container 7 and placing it on the inspection stage 14, As described above, the elevator 22, the transfer robot 23, and the pre-aligner 24 are arranged. These are connected to a control computer 61 arranged in the external unit 50 via a robot control interface 61b. A control signal is sent from the control computer 61 to the elevator 22, the transport robot 23, and the pre-aligner 24 via the robot control interface 61b.
[0065]
That is, when the semiconductor wafer that has been carried in the sealed container 7 is taken out from the cassette 7b of the container 7 and placed on the inspection stage 14, the control computer 61 through the robot control interface 61b. Control signals are sent to the elevator 22, the transport robot 23, and the pre-aligner 24. Then, the elevator 22, the transfer robot 23, and the pre-aligner 24 operate based on this control signal. As described above, the semiconductor wafer that has been transferred into the sealed container 7 is transferred to the cassette 7b of the container 7. , Phase alignment and center alignment by the pre-aligner 25 are performed, and the sample is placed on the inspection stage 14.
[0066]
In addition, a vibration isolation table 13 is disposed inside the clean box 3 of the inspection apparatus 1, and the X stage 15, the Y stage 16, the θ stage 17, and the Z stage are arranged on the vibration isolation table 13 as described above. An inspection stage 14 provided with 18 and a suction plate 19 is installed.
[0067]
Here, the X stage 15, the Y stage 16, the θ stage 17, the Z stage 18, and the suction plate 19 are connected to a control computer 61 disposed in the external unit 50 via a stage control interface 61c. A control signal is sent from the control computer 61 to the X stage 15, Y stage 16, θ stage 17, Z stage 18 and suction plate 19 via the stage control interface 61c.
[0068]
That is, when a semiconductor wafer is inspected, 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. . The X stage 15, Y stage 16, θ stage 17, Z stage 18, and suction plate 19 operate based on this control signal, and the suction plate 19 sucks and fixes the semiconductor wafer to be inspected. The stage 15, the Y stage 16, the θ stage 17, and the Z stage 18 move the semiconductor wafer to a predetermined position, angle, and height.
[0069]
Further, as described above, the optical unit 21 is also installed on the vibration isolation table 12. This optical unit 21 is for capturing an image of a semiconductor wafer at the time of inspection of a semiconductor wafer. As described above, the function of capturing an image of a semiconductor wafer to be inspected with low resolution using visible light. And a function of taking an image of a semiconductor wafer to be inspected with high resolution using ultraviolet light.
[0070]
The optical unit 21 has a visible light CCD camera 30, a halogen lamp 32, a visible light optical system 33, and a visible light objective lens 34 as a mechanism for capturing an image of a semiconductor wafer with visible light. And an autofocus control unit 35 for visible light.
[0071]
When an image of the semiconductor wafer is picked up with visible light, the halogen lamp 32 is turned on. Here, the drive source of the halogen lamp 32 is connected to a control computer 61 disposed 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 halogen lamp 32 via the light source control interface 61d. The halogen lamp 32 is turned on / off based on this control signal.
[0072]
When an image of the semiconductor wafer is picked up with visible light, the halogen lamp 32 is turned on, and the visible light from the halogen lamp 32 is transmitted through the visible light optical system 33 and the visible light objective lens 34 to the semiconductor. The semiconductor wafer is illuminated against the wafer. Then, the image of the semiconductor wafer illuminated with visible light is magnified by the visible light objective lens 34, and the magnified image is captured by the visible light CCD camera 30.
[0073]
Here, the visible light CCD camera 30 is connected to an image processing computer 60 disposed in the external unit 50 via an image capture interface 60b. The semiconductor wafer image captured by the visible light CCD camera 30 is captured by the image processing computer 60 via the image capture interface 60b.
[0074]
Further, when an image of a semiconductor wafer is picked up with visible light as described above, automatic focus position alignment is performed by the visible light autofocus control unit 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. Moves the visible light objective lens 34 or the Z stage 18 so that the inspection target surface of the semiconductor wafer coincides with the focal plane of the visible light objective lens 34.
[0075]
Here, the visible light autofocus control unit 35 is connected to a control computer 61 disposed in the external unit 50 via an autofocus control interface 61e. A control signal is sent from the control computer 61 to the visible light autofocus control unit 35 via the autofocus control interface 61e. The automatic focus position adjustment of the visible light objective lens 34 by the visible light autofocus control unit 35 is performed based on this control signal.
[0076]
The optical unit 21 has a CCD camera 31 for ultraviolet light, an ultraviolet light laser light source 36, an optical system 37 for ultraviolet light, and an objective for ultraviolet light as a mechanism for taking an image of a semiconductor wafer with ultraviolet light. A lens 38 and an ultraviolet autofocus control unit 39 are provided.
[0077]
Then, when an image of the semiconductor wafer is taken with ultraviolet light, the ultraviolet light source 36 is turned on. Here, the drive source of the ultraviolet laser light source 36 is connected to a control computer 61 disposed 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. The ultraviolet laser light source 36 is turned on / off based on this control signal.
[0078]
In addition, it is preferable to use the ultraviolet laser light source 36 that emits an ultraviolet laser having a wavelength of about 266 nm. An ultraviolet 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 36.
[0079]
When an image of a semiconductor wafer is taken with ultraviolet light, the ultraviolet laser light source 36 is turned on, and the ultraviolet light from the ultraviolet light laser light source 36 is passed through the ultraviolet light optical system 37 and the ultraviolet light objective lens 38. The semiconductor wafer is then illuminated and illuminated. Then, the image of the semiconductor wafer illuminated by the ultraviolet light is magnified by the ultraviolet light objective lens 38, and the magnified image is picked up by the ultraviolet light CCD camera 31.
[0080]
Here, the ultraviolet CCD camera 31 is connected to an image processing computer 60 disposed in the external unit 50 via an image capturing interface 60c. Then, the image of the semiconductor wafer captured by the ultraviolet CCD camera 31 is captured by the image processing computer 60 via the image capture interface 60c.
[0081]
Further, as described above, when an image of a semiconductor wafer is picked up with ultraviolet light, automatic focusing is performed by the ultraviolet light autofocus control unit 39. That is, the ultraviolet light autofocus control unit 39 detects whether or not the distance between the ultraviolet light objective lens 38 and the semiconductor wafer matches the focal length of the ultraviolet light objective lens 38. Moves the ultraviolet light objective lens 38 or the Z stage 18 so that the inspection target surface of the semiconductor wafer coincides with the focal plane of the ultraviolet light objective lens 38.
[0082]
Here, the ultraviolet autofocus control unit 39 is connected to a control computer 61 disposed in the external unit 50 via an autofocus control interface 61e. A control signal is sent from the control computer 61 to the ultraviolet light autofocus control unit 39 via the autofocus control interface 61e. The automatic focusing position adjustment of the ultraviolet light objective lens 38 by the ultraviolet light autofocus control unit 39 is performed based on this control signal.
[0083]
Further, the clean air unit 4 is provided with two blowers 5a and 5b as described above. These blowers 5a and 5b are connected to a control computer 61 disposed in the external unit 50 through 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 rotational speed of the blowers 5a and 5b, switching between on / off, and the like are performed based on this control signal.
[0084]
Next, the optical system of the optical unit 21 of the inspection apparatus 1 will be described in more detail with reference to FIG. Here, description of the autofocus control units 35 and 39 is 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.
[0085]
As shown in FIG. 5, the optical unit 21 includes a halogen lamp 32, a visible light optical system 33, and a visible light objective lens 34 as an optical system for capturing an image of a semiconductor wafer with visible light. I have.
[0086]
Visible light from the halogen lamp 32 is guided to the visible light optical system 33 by the optical fiber 40. 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. The visible light incident on the half mirror 43 is reflected by the half mirror 43 toward the visible light objective lens 34 and enters the semiconductor wafer via the visible light objective lens 34. Thereby, the semiconductor wafer is illuminated with visible light.
[0087]
The image of the semiconductor wafer illuminated with visible light is enlarged by the visible light objective lens 34, 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 is incident on the visible light CCD camera 30 via the visible light objective lens 34, the half mirror 43, and the imaging lens 44. An enlarged image is captured by the visible light CCD camera 30. Then, an image of the semiconductor wafer (hereinafter referred to as a visible image) picked up by the visible light CCD camera 30 is sent to the image processing computer 60.
[0088]
The optical unit 21 includes an ultraviolet laser light source 36, an ultraviolet light optical system 37, and an ultraviolet light objective lens 38 as an optical system for capturing an image of a semiconductor wafer with ultraviolet light. .
[0089]
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. The visible light incident on the half mirror 48 is reflected by the half mirror 48 toward the ultraviolet light objective lens 38 and enters the semiconductor wafer via the ultraviolet light objective lens 38. Thereby, the semiconductor wafer is illuminated with ultraviolet light.
[0090]
The image of the semiconductor wafer illuminated with ultraviolet light is magnified by the ultraviolet light objective lens 38, 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 the ultraviolet light is incident on the ultraviolet CCD camera 31 through the ultraviolet objective lens 38, the half mirror 48, and the imaging lens 49. An enlarged image is picked up by the CCD camera 31 for ultraviolet light. An image of the semiconductor wafer (hereinafter referred to as an ultraviolet image) captured by the ultraviolet CCD camera 31 is sent to the image processing computer 60.
[0091]
In the inspection apparatus 1 as described above, an image of a semiconductor wafer can be captured and inspected with ultraviolet light, which is light having a wavelength shorter than that of visible light. Therefore, detection and classification of defects are performed using visible light. Compared with the case where it carries out, a finer defect detection and classification can be performed.
[0092]
In addition, the inspection apparatus 1 has both an optical system for visible light and an optical system for ultraviolet light, so that inspection of a semiconductor wafer with low resolution using visible light and high resolution using ultraviolet light are possible. Both of the semiconductor wafer inspection and the semiconductor wafer inspection can be performed. Therefore, in the inspection apparatus 1, large defects are detected and classified by inspection of the semiconductor wafer at low resolution using visible light, and inspection of the semiconductor wafer at high resolution using ultraviolet light is performed. It is also possible to detect and classify small defects.
[0093]
In the inspection apparatus 1, the numerical aperture NA of the ultraviolet light objective lens 41 is preferably large, for example, 0.9 or more. Thus, by using a lens having a large numerical aperture NA as the ultraviolet objective lens 41, it becomes possible to detect a finer defect.
[0094]
By the way, when the defect of the semiconductor wafer is composed only of irregularities without color information like a scratch, the defect can hardly be seen with light having no coherence. On the other hand, when light with excellent coherence such as laser light is used, even if the defect has no color information and has only irregularities, such as scratches, light is emitted near the irregularities. By interfering, the defect can be clearly seen. The inspection apparatus 1 uses an ultraviolet laser light source 36 that emits ultraviolet laser light as an ultraviolet light source. Therefore, the inspection apparatus 1 can clearly detect the defect even if the defect has no color information and has only unevenness, such as a scratch. That is, in the inspection apparatus 1, phase information that is difficult to detect with visible light (incoherent light) from the halogen lamp 32 is easily detected using the ultraviolet light laser (coherent light) from the ultraviolet light source 36. can do.
[0095]
Next, an example of a procedure when the semiconductor wafer is inspected by the inspection apparatus 1 will be described with reference to the flowchart of FIG. In the flowchart of FIG. 6, the processing procedure after the state in which the semiconductor wafer to be inspected is placed on the inspection stage 14 is shown. Further, the flowchart shown in FIG. 6 shows an example of a procedure for performing classification by inspecting the defect by the inspection apparatus 1 when the position of the defect on the semiconductor wafer is known in advance. Also, here, it is assumed that many similar device patterns are formed on a semiconductor wafer, and defect detection and classification are performed by using an image of a defect area (defect image) and an image of other areas (reference image). ), And comparing them.
[0096]
First, as shown in step S1-1, the defect position coordinate file is read into the control computer 61. Here, the defect position coordinate file is a file in which information on 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. Here, the defect position coordinate file is read into the control computer 61.
[0097]
Next, in step S1-2, the X stage 15 and the Y stage 16 are driven by the control computer 61, the semiconductor wafer is moved to the defect position coordinates indicated by the defect position coordinate file, and the inspection target area of the semiconductor wafer is visible light. The objective lens 34 is within the field of view.
[0098]
Next, in step S <b> 1-3, the visible light autofocus control unit 35 is driven by the control computer 61 to perform automatic focus alignment of the visible light objective lens 34.
[0099]
Next, in step S <b> 1-4, 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. Note that 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 an area where there is a defect (hereinafter referred to as a defect image).
[0100]
Next, in step S1-5, the X stage 15 and the Y stage 16 are driven by the control computer 61, the semiconductor wafer is moved to the reference position coordinates, and the reference area of the semiconductor wafer is the visual field of the visible light objective lens 34. Get inside. 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.
[0101]
Next, in step S1-6, the control computer 61 drives the visible light autofocus control unit 35 to perform automatic focus alignment of the visible light objective lens.
[0102]
Next, in step S1-7, an image of the semiconductor wafer is picked up by the visible light CCD camera 30, and the picked-up visible image is sent to the image processing computer 60. The visible image captured here is an image of an area where a device pattern similar to the device pattern in the inspection target area of the semiconductor wafer is formed (hereinafter referred to as a reference image).
[0103]
Next, in step S1-8, the image processing computer 60 compares the defect image captured in step S1-4 with the reference image captured in step S1-7, and detects a defect from the defect image. If a defect can be detected, the process proceeds to step S1-9. If a defect cannot be detected, the process proceeds to step S1-11.
[0104]
In step S1-9, the image processing computer 60 examines what the detected defect is and classifies it. If the defect classification is completed, the process proceeds to step S1-10. If the defect classification cannot be performed, the process proceeds to step S1-11.
[0105]
In step S1-10, the defect classification result 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. The defect classification result may be transferred to and stored in another computer connected to the image processing computer 60 or the control computer 61 via a network.
[0106]
When the process in step S1-10 is completed, the classification of defects of the semiconductor wafer is completed, and thus the process ends. 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.
[0107]
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 thereafter, and high resolution is obtained using ultraviolet light. Defect detection and classification are performed by imaging.
[0108]
In that case, first, in step S1-11, the X stage 15 and the Y stage 16 are driven by the control computer 61, and the semiconductor wafer is moved to the defect position coordinates indicated by the defect position coordinate file. The region is set within the field of view of the objective lens 38 for ultraviolet light.
[0109]
Next, in step S1-12, the control computer 61 drives the ultraviolet light autofocus control unit 39 to perform automatic focus alignment of the ultraviolet light objective lens 38.
[0110]
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, the imaging of the defect image here is performed with higher resolution than that in the case of using visible light by using ultraviolet light, which is light having a shorter wavelength than visible light.
[0111]
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, so that the reference region of the semiconductor wafer is the field of view of the ultraviolet objective lens 38. Get inside. 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.
[0112]
In step S1-15, the control computer 61 drives the ultraviolet light autofocus control unit 39 to perform automatic focus alignment of the ultraviolet light objective lens 38.
[0113]
In step S1-16, an image of the semiconductor wafer is picked up by the ultraviolet CCD camera 31, and the picked-up 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. Further, the reference image is captured here using ultraviolet light having a shorter wavelength than visible light with higher resolution than when visible light is used.
[0114]
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. If a defect can be detected, the process proceeds to step S1-18. If a defect cannot be detected, the process proceeds to step S1-19.
[0115]
In step S1-18, the image processing computer 60 examines what the detected defect is and classifies it. If the defect classification is 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.
[0116]
In step S1-19, information indicating that the defect cannot be classified is stored. Here, the information indicating that the defect classification could not be performed is stored in, for example, a storage device connected to the image processing computer 60 or the control computer 61. This information may be transferred to and stored in another computer connected to the image processing computer 60 or the control computer 61 via a network.
[0117]
According to the above procedure, first, a semiconductor wafer is inspected at a low resolution by processing and analyzing an image captured by the visible light CCD camera 30 to detect and classify defects with visible light. If not, next, the semiconductor wafer is inspected with high resolution by processing and analyzing the image captured by the ultraviolet CCD camera 31.
[0118]
Here, a method for detecting a defect from a reference image and a defect image captured by the CCD cameras 30 and 31 will be described with reference to FIG.
[0119]
FIG. 7A shows an example of an image of a reference area on which a device pattern similar to the device pattern in the inspection target area is formed, that is, a reference image. FIG. 7B shows an example of an image of a region to be inspected that has a defect, that is, a defect image.
[0120]
When a defect is detected from such a reference image and a defect image, a device pattern is extracted from the reference image based on color information and shading information as shown in FIG. 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.
[0121]
Then, as shown in FIG. 7E, an image obtained by superimposing the device pattern extraction result image shown in FIG. 7C and the defect extraction result image shown in FIG. 7D is obtained. The ratio of the defect existing in the device pattern is extracted as a feature amount related to the defect.
[0122]
By the above-described method, the reference image and the defect image captured by the CCD cameras 30 and 31 are processed and analyzed by the image processing computer 60, so that the defect can be detected and the semiconductor wafer can be inspected.
[0123]
As described above, the inspection apparatus 1 first inspects a semiconductor wafer with low resolution by processing and analyzing an image captured by the visible light CCD camera 30 to detect defects in visible light. When the classification cannot be performed, the semiconductor wafer is inspected at high resolution by processing and analyzing the image captured by the ultraviolet CCD camera 31. Compared with the case of detecting and classifying defects using the, it is possible to detect and classify finer defects.
[0124]
However, since the area that can be imaged at once is wider when imaging with low resolution using visible light, if the defect is sufficiently large, the semiconductor wafer was inspected with low resolution using visible light. Is more efficient. Therefore, rather than using ultraviolet light from the beginning to inspect and classify defects, as described above, by first inspecting and classifying defects using visible light, it is more efficient. A semiconductor wafer can be inspected.
[0125]
By the way, in this inspection apparatus 1, as described above, the semiconductor wafer is illuminated with visible light or ultraviolet light, the image of the semiconductor wafer illuminated with visible light or ultraviolet light is enlarged, and the enlarged image is converted into visible light. The image is taken by the CCD camera 30 or the ultraviolet CCD camera 31.
[0126]
However, in the conventional inspection apparatus, when such a visible light CCD camera 30 or an ultraviolet light CCD camera 31 is installed in the optical unit 21, it is transmitted from the outside transmitted to the wiring routed to these CCD cameras. Due to the load, vibration, and the like, the CCD camera may be displaced or vibrated, and a clear image of the semiconductor wafer may not be captured.
[0127]
Therefore, in the inspection apparatus 1, as shown in FIG. 8, the CCD camera for visible light 30 and the CCD camera for ultraviolet light 36 have a first support member 70, a second support member 71, and a third support, respectively. While being supported by the member 72, the optical unit 21 is fixed at a predetermined position.
[0128]
In the following description, the visible light CCD camera 30 and the ultraviolet light CCD camera 31 are similarly fixed by the first support member 70, the second support member 71, and the third support member 72, respectively. Thus, the visible light CCD camera 30 and the ultraviolet light CCD camera 31 are collectively described as a CCD camera 73.
[0129]
The CCD camera 73 has a substantially rectangular shape as a whole, and has a light receiving window 74 for capturing an image of a semiconductor wafer on the front surface and a wiring 75 connected to the image processing computer 60 on the rear surface. ing. A spacer member 76 is attached to the front surface of the CCD camera 73 so as to be positioned below the light receiving window 74. The spacer member 76 is used to attach the first support member 70 to the front surface of the CCD camera 73. The spacer member 76 is located on the front surface of the spacer member 76 at both ends in the longitudinal direction. A pair of first screw holes 77 for attaching 70 is provided. That is, the first support member 70 is attached to the CCD camera 73 via the spacer member 76. Further, a second screw hole 78 for attaching a third support member is provided on the upper surface of the CCD camera 71 at a substantially central portion.
[0130]
The first support member 70 is for supporting the front surface of the CCD camera 73, and has a shape obtained by bending a substantially flat plate member made of metal or the like into a substantially L shape. Of these, the one piece of the first support member 70 bent into a substantially L-shape is a first fixed piece portion 70a fixed on the mounting surface of the optical unit 21, and this first fixed piece portion. 70a is provided with a pair of first holes 79 for fixing the first support member 70 on the mounting surface at both ends in the longitudinal direction. On the other hand, the other piece of the first support member 70 bent into a substantially L shape is a first support piece portion 70b that supports the CCD camera 73, and the first support piece portion 70b includes the first support piece portion 70b. A substantially circular opening 80 corresponding to the light receiving window 74 of the CCD camera 73 is provided at the center. The first support piece 70 b is provided with a pair of second holes 81 corresponding to the screw holes 77 of the spacer member 76 located at both ends on the lower side of the opening 80.
[0131]
The second support member 71 is for supporting one side surface of the CCD camera 73, and has a shape in which a substantially flat plate member made of metal or the like is bent into a substantially L shape. Among these, the one piece of the second support member 71 bent into a substantially L shape is a second fixed piece portion 71a fixed on the mounting surface of the optical unit 21, and this second fixed piece portion. 71a is provided with a pair of third holes 82 for fixing the second support member 70 on the mounting surface at both ends in the longitudinal direction. On the other hand, the other piece of the second support member 71 bent into a substantially L shape is a second support piece portion 71b that supports the CCD camera 73, and the second support piece portion 71b includes an upper portion thereof. The third support member 72 is attached by the first bolt 83 so as to be substantially parallel to the direction opposite to the bending direction of the second fixed piece 71a.
[0132]
The third support member 72 is for supporting the upper surface of the CCD camera 73, and is formed of a metal or the like in a substantially flat plate shape. As described above, the third support member 72 is integrated with the second support member 71 by being attached to the second support member 71, and together with the second support piece portion 71a, the fixed piece portion. It is configured to be bent in a substantially L shape so as to be substantially parallel to the direction opposite to the bending direction of 71a. In addition, the third support member 72 is provided with a fourth hole portion 84 corresponding to the first screw hole 78 of the CCD camera 73 located substantially at the center thereof.
[0133]
In this inspection apparatus 1, as shown in FIGS. 8 and 9, a first support member 70 is attached to the front surface of the CCD camera 73 via a spacer member 76.
[0134]
When attaching the first support member 70, the opening 80 of the first support piece 70 a engages with the light receiving window 74 of the CCD camera 73, and the first hole 81 is the first of the spacer member 76. The first support piece 70 a is brought into contact with the front surface of the CCD camera 73 to which the spacer member 76 is attached so as to substantially coincide with the screw hole 77. Then, the first support piece 70 a is fixed to the spacer member 76 by screwing the second bolt 85 into the first screw hole 77 through the first hole 81. As a result, the first support member 70 is attached to the front surface of the CCD camera 73 via the spacer member 76.
[0135]
The CCD camera 73 to which the first support member 70 is attached is placed at a predetermined position of the optical unit 21. Then, the first fixing piece 70 a of the first support member 70 is fixed on the mounting surface of the optical unit 21 by the third bolt 86 through the second hole 79.
[0136]
As a result, in the inspection apparatus 1, the first support member 70 supports the front surface of the first CCD camera 73 and fixes the first CCD camera 73 on the mounting surface of the optical unit 21. .
[0137]
In the inspection apparatus 1, a third support member 72 integrated with the second support member 71 is attached to the upper surface of the CCD camera 73.
[0138]
When the third support member 72 integrated with the second support member 71 is attached, the fourth hole portion 84 of the third support member 72 substantially coincides with the second screw hole 78 of the CCD camera 73. As described above, the third support member 72 and the second support piece 71 a of the second support member 71 are brought into contact with the upper surface and one side surface of the CCD camera 73, respectively. Then, the third support member 72 is fixed to the upper surface of the CCD camera 73 by screwing the fourth bolt 87 into the second screw hole 78 through the fourth hole portion 84. As a result, the second support member 71 and the third support member 72 are attached to the upper surface and one side surface of the CCD camera 73.
[0139]
Then, the second fixing piece 70 a of the second support member 71 is fixed on the mounting surface of the optical unit 21 by the fifth bolt 88 through the third hole 82.
[0140]
As a result, in the inspection apparatus 1, the second support member 71 and the third support member 72 support the one side surface and the top surface of the CCD camera 73, and the CCD camera 73 is fixed on the mounting surface of the optical unit 21. Will do.
[0141]
In the inspection apparatus 1, the support member 70, the second support member 71, and the third support member 72 support the CCD camera 73 as described above, and the CCD camera 73 is mounted on the mounting surface of the optical unit 21. Secure on top. Thereby, in this inspection apparatus 1, it is possible to prevent the occurrence of displacement or vibration in the CCD camera 73.
[0142]
Specifically, in the inspection apparatus 1, as shown in FIG. 9, the first support member 70 can prevent the CCD camera 73 from moving in the X1 direction in the drawing.
Further, the second support member 71 can prevent the CCD camera 73 from moving in the Y1 direction in the drawing. Further, the third support member 72 can prevent the CCD camera 73 from moving in the Z1 direction in the drawing.
[0143]
Further, in the inspection apparatus 1, the first support member 70, the second support member 71, and the third support member 72 can prevent the CCD camera 73 from rotating in the X2 direction in the drawing. Further, the first support member 70 and the second support member 71 can prevent the CCD camera 73 from rotating in the Z2 direction in the figure.
[0144]
Thus, in the inspection apparatus 1, the CCD camera 73 can be installed in a stable state inside the optical unit 21. Therefore, the inspection apparatus 1 can capture a clearer image of the semiconductor wafer, and can appropriately detect and classify finer defects on the semiconductor wafer.
[0145]
In particular, since this inspection apparatus 1 inspects a semiconductor wafer with high resolution using ultraviolet light, preventing the occurrence of positional deviation or vibration of the CCD camera 73 is inspected with such high resolution. It is very effective in performing properly.
[0146]
Further, conventionally, when such a CCD camera is fixed by a support member, in order to prevent the occurrence of positional deviation or vibration of the CCD camera, a fastening bolt for fastening the CCD camera and the support member is firmly tightened. As a result, the CCD camera may be distorted.
[0147]
On the other hand, in this inspection apparatus 1, the CCD is performed without firmly tightening the second bolt 85 and the fifth bolt 88 that fasten the first support member 70 and the third support member 72 and the CCD camera 73. The camera 73 can be firmly fixed by the first support member 70, the second support member 71, and the third support member 72.
[0148]
Therefore, in this inspection apparatus 1, the CCD camera 73 is not distorted, and the CCD camera 73 can be stably installed inside the optical unit 21.
[0149]
In the inspection apparatus 1, the third support member 72 is attached to the second support member 71. However, the configuration is not necessarily limited to such a configuration. The member 72 may be configured to be attached to the first support member 70.
[0150]
In this case, the first support member 70 is positioned on the upper portion of the first support piece portion 70b and is substantially parallel to the direction opposite to the bending direction of the first fixed piece portion 70a. The support member 72 is attached. Thereby, the effect similar to the test | inspection apparatus 1 mentioned above can be acquired.
[0151]
In the above description, the inspection apparatus 1 to which the present invention is applied has been used for examining what a defect of a semiconductor wafer is. However, the application of the inspection apparatus 1 according to the present invention can be used for applications other than defect identification of semiconductor wafers. That is, the inspection apparatus 1 according to the present invention can be used, for example, to inspect whether or not a device pattern formed on a semiconductor wafer is formed in an appropriate shape according to a desired pattern. Furthermore, the use of the inspection apparatus 1 according to the present invention is not limited to the inspection of semiconductor wafers, and the inspection apparatus 1 according to the present invention can be widely applied to inspection of fine patterns. It is also effective for inspection of flat panel displays on which various patterns are formed.
[0152]
【The invention's effect】
As described above in detail, in the inspection apparatus according to the present invention, the imaging unit is stably installed on the support base by the first support member, the second support member, and the third support member. Therefore, it is possible to prevent the image pickup means from being displaced or vibrated. Therefore, in this inspection apparatus, it is possible to capture a clearer image of the inspection object, and it is possible to appropriately detect and classify a finer defect of the inspection object.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an external appearance of an inspection apparatus to which the present invention is applied.
FIG. 2 is a view showing a state in which an apparatus main body disposed inside a clean box of the inspection apparatus is viewed from the direction of arrow A in FIG.
FIG. 3 is a plan view schematically showing an apparatus main body of the inspection apparatus.
FIG. 4 is a block diagram illustrating a configuration example of the inspection apparatus.
FIG. 5 is a diagram illustrating a configuration example of an optical system of an optical unit of the inspection apparatus.
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 technique for detecting a defect from a reference image and a defect image.
FIG. 8 is an exploded perspective view for explaining the configuration of a CCD camera and a first support member, a second support member, and a third support member for fixing the CCD camera.
FIG. 9 is a perspective view showing a state in which the CCD camera is fixed inside the optical unit by a first support member, a second support member, and a third support member.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Inspection apparatus, 2 Clean unit, 3 Clean box, 4 Clean air unit, 5a, 5b Blower, 10 Main body, 14 Inspection stage, 21 Optical unit, 22 Elevator, 23 Transport robot, 24 Pre-aligner, 30 For visible light CCD camera, 31 Ultraviolet light CCD camera, 32 Halogen lamp, 33 Visible light optical system, 34 Visible light objective lens, 36 Ultraviolet light source, 37 Ultraviolet light optical system, 38 Ultraviolet light objective lens, 50 External Unit, 52, 53 display device, 54 input device, 60 image processing computer, 61 control computer, 70 first support member, 70a first fixed piece, 70b first support piece, 71 second Support member, 71a 2nd fixed piece part, 71b 2nd fixed piece part, 72 3rd support member, 73 CCD Mera, 74 light receiving window

Claims (1)

In an inspection apparatus that inspects an inspection object by taking an image of the inspection object, processing and analyzing the image,
A substantially rectangular imaging means placed on a support table;
A first support member fixed on the support base and fixed to the front surface of the imaging means on which the image of the inspection object is captured;
A second support member that supports one side of the imaging means and is fixed on the support;
Is fixed to the upper surface of the imaging means, and a third supporting member fixed to the upper Symbol second support member,
The imaging means is a CCD camera for visible light and a CCD camera for ultraviolet light. After the image of the inspection object illuminated by visible light is captured, the image of the inspection object illuminated by ultraviolet light is captured An inspection apparatus characterized by:

Images