JP2002368051A - Dust monitor and method for monitoring dust - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive high speed dust monitor and a method for monitoring dust in which a dust adhering to the surface of a substrate can be detected accurately even when a pattern is being transferred onto the surface of the substrate. SOLUTION: A capturing sheet 22 is brought into contact or close to the surface of a wafer 16 processed in a processing system 12 and a dust 20 on the surface of the wafer 16 is captured on the capturing sheet 22. The dust 20 captured on the capturing sheet 22 is detected by a dust inspection equipment, e.g. an optical detector 24, for detecting the dust 20 on the surface of the wafer 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a foreign substance monitoring technique, and more particularly, to a foreign substance monitoring apparatus and a foreign substance monitoring method for detecting foreign substances such as dust adhering to a semiconductor substrate or a glass substrate.

[0002]

2. Description of the Related Art In a manufacturing process of a semiconductor device, a liquid crystal display, or the like, integration of a transfer pattern on a substrate including a semiconductor substrate (that is, a wafer) or a glass substrate is progressing.
For this reason, if fine foreign matter adheres to the substrate surface before or during the manufacturing process, the foreign matter enters the formed film, deteriorating the device characteristics, or the foreign matter serves as a mask to prevent abnormalities in the transfer pattern. In some cases, resulting in the production of an inconvenient product substrate. Therefore, in order to reduce the influence of the foreign matter, the foreign matter attached to the substrate is often removed or washed before the substrate is sent to a new manufacturing process. Methods for removing such foreign matter include JP-A-6-232108, JP-A-6-260464, and JP-A-7-94.
As described in, for example, JP-A-563-563, there is included one that removes foreign matter using an adhesive material such as an adhesive sheet.

[0003]

However, as described above, new foreign matter may adhere to the substrate during the manufacturing process, and this foreign matter may serve as a mask to cause an abnormality in a transfer pattern. I know. Even if such foreign matter is removed after passing through the process, it often causes an abnormality in the transfer pattern to the substrate. Therefore, it is necessary to monitor foreign substances adhering to the substrate during the manufacturing process, detect occurrence of defective products, and eliminate defective products. Furthermore, in order to improve the product yield, it is effective to newly adjust the manufacturing process when it is detected that the frequency of occurrence of defects due to foreign matter has been increased.

Devices for monitoring such foreign substances are roughly classified into optical detection devices and visual inspection devices. The optical detection device scans a substrate with a laser beam and detects foreign substances on the substrate by light scattering or light reflection from the substrate surface. Therefore, it has the advantage that it can be inspected at low cost and high throughput (high throughput). On the other hand, it is applied to a substrate with a pattern transferred to the surface and has irregularities, and detects foreign matter adhering to the substrate surface. Have the disadvantage of being difficult. For this reason, when applying the optical detection device to the substrate on which the pattern has been transferred,
A dummy substrate with no irregularities on the surface is mixed at a fixed ratio with the actual substrate for the product, and the dummy substrate is flowed under the same processing conditions as normal except that pattern transfer is not performed. By detecting attached foreign matter,
The foreign substances in the process equipment are monitored.

On the other hand, a visual inspection apparatus detects foreign matter adhering to a substrate by comparing patterns between a bright-field image of the substrate and a reference substrate image. Therefore, if the image of the pattern-transferred substrate to which no foreign matter is adhered after the process is used as the reference substrate image, the pattern-transferred substrate can be accurately inspected for foreign matter. . On the other hand, there is a drawback in that it is necessary to compare the pattern of the image, so that the apparatus is expensive and the processing capacity is low.

Further, in the above two types of conventional foreign substance monitoring technologies, when foreign substances are monitored using a dummy substrate using an optical detection device, the foreign substance inspection is performed intermittently. When the equipment is used, the processing capacity is low, so when a foreign substance is detected in excess of the actually permitted number, a plurality of substrates have already passed through the process equipment, and the substrate failure due to the foreign substance can be quickly performed. There is a problem that it is not possible to perform an accurate detection.

[0007] Accordingly, an object of the present invention is to solve the above-mentioned problems in the prior art, and to accurately detect foreign matter adhering to the substrate surface even when pattern transfer is performed on the substrate surface. It is still another object of the present invention to provide an inexpensive and high-speed foreign substance monitoring technique capable of specifying the position of a foreign substance on a substrate.

[0008]

SUMMARY OF THE INVENTION In view of the above object, the present invention does not directly detect foreign substances on a substrate surface by a foreign substance inspection device, but temporarily converts the foreign substances on the substrate surface into a capture sheet without irregularities. The foreign matter attached to the substrate surface is indirectly monitored by detecting the foreign matter captured and captured on the capture sheet.

That is, in order to achieve the above object, according to the first invention, a capture sheet for contacting or approaching the surface of a transferred substrate to capture foreign substances on the surface of the substrate; There is provided a foreign matter monitoring device including a foreign matter inspection device that detects foreign matter captured on the capture sheet in order to detect a foreign matter on a surface. In the above foreign matter monitoring device, it is preferable that the foreign matter inspection device comprises an optical or electrical foreign matter inspection device.

Further, according to the second aspect of the present invention, the capture sheet is brought into contact with or close to the surface of the substrate that has been treated in the processing apparatus, and foreign matter on the substrate surface is captured by the capture sheet. There is provided a foreign matter monitoring method for detecting a foreign matter captured on the capture sheet by a foreign matter inspection device in order to detect the foreign matter. In the above foreign matter monitoring method, preferably, the foreign matter inspection device detects at least one of the quantity, size, position, and type of the foreign matter. More preferably, based on a detection result of the foreign substance inspection device, it is determined whether or not the substrate is acceptable or operation control of the process device is performed.

The capture sheet of the present invention captures foreign matter by, for example, any one of adhesive force, Coulomb force and intermolecular force. Further, the foreign matter inspection device detects foreign matter on the capture sheet before and after the foreign matter on the substrate surface is captured by the capture sheet, and detects foreign matter that has increased after capture in the capture sheet as compared to before capture in the capture sheet. It is preferable to recognize as a foreign substance.

According to the present invention, a foreign substance adhering to the surface of a substrate including a semiconductor substrate and a glass substrate is not directly detected by a foreign substance inspection apparatus, but the foreign substance on the substrate surface is captured by a capture sheet. The foreign matter captured on the substrate is detected by a foreign matter inspection device, so that the foreign matter on the substrate surface is indirectly detected. That is,
Since foreign matter captured on the capture sheet is detected after capturing the foreign matter on the capture sheet with no pattern on the surface, even if the pattern has been transferred to the substrate surface and there are irregularities, light using light scattering or reflected light is used. It becomes easy to detect foreign matter on the capture sheet using an optical or electric detection device having a low-speed and high-speed processing capability such as a sensor.

Further, the foreign matter is adsorbed or captured by the capture sheet by bringing the capture sheet into contact with or close to the substrate surface, so that there is a correspondence between the coordinate position on the substrate surface and the coordinate position on the capture sheet. To establish. Therefore, if a predetermined relationship is maintained between the position of the capture sheet when contacting or approaching the substrate surface and the position of the capture sheet when foreign matter is detected by the foreign matter inspection device, foreign matter inspection is performed. From the position of the foreign matter detected on the capture sheet by the apparatus, the position where the foreign matter was present on the substrate surface can also be specified. Therefore, it is also possible to determine the magnitude of the influence based on the position of the foreign matter and determine whether the substrate is acceptable or not. Further, by monitoring the position of the foreign matter on the substrate over time, it is possible to specify the place where the foreign matter has occurred in the process apparatus.

In addition, since the foreign matter adhering to the substrate on which the pattern has been transferred can be detected by the optical detection device, a high-speed foreign matter inspection of the processed substrate can be performed, and the foreign matter inspection can be performed online. . in addition,
By scanning the optical sensor, it is possible to detect the quantity, size, position, and type of the foreign matter. Monitor the change in the number of foreign substances, and immediately stop the operation of the process equipment or adjust the operating parameters when foreign substances exceeding a certain number or size are detected. Operation control can be performed. Thereby, the yield of the product substrate can be improved.

Further, if foreign matter on the capture sheet is detected before and after the foreign matter is captured, and the increment is recognized as foreign matter on the substrate surface, the foreign matter attached to the capture sheet in advance gives the detection of foreign matter on the substrate surface. The influence is removed, and the foreign matter can be detected with higher accuracy. Note that the foreign substance inspection apparatus in the present application refers to the entire apparatus capable of performing a foreign substance inspection, and includes the above-described optical or electric detection apparatus and the appearance inspection apparatus that detects a foreign substance using an image. It is a thing.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a simplified perspective view showing an entire configuration of an embodiment of a foreign substance monitoring device according to the present invention, and FIGS. 2 to 4 show a series of operations of the foreign substance monitoring device shown in FIG. It is a schematic diagram. Although the foreign substance monitoring apparatus shown in FIGS. 1 to 4 targets a wafer which is a kind of semiconductor substrate, the wafer is merely an example, and the foreign substance monitoring apparatus of the present invention is used for the purpose of foreign substance inspection on a wafer. The present invention is not limited thereto, and may be applied to any substrate on which a surface is subjected to some processing such as pattern transfer. Note that the term “substrate” in the present application includes a semiconductor substrate such as a wafer and a glass substrate used for a liquid crystal panel and the like.

Referring to FIG. 1, a foreign substance monitoring apparatus 10 of the present invention is provided immediately after a processing apparatus 12, and is configured to transfer a wafer 16 transferred from the processing apparatus 12 via a substrate transfer apparatus such as a robot arm 14. Upon receipt, inspection of foreign substances such as dust and processing dust adhering to the surface of the wafer 16 is performed. Here, the process device 12 is used for pattern 1
8 is performed on the substrate such as the wafer 16 such as transfer to the surface and polishing and cleaning of the substrate.

The foreign matter monitoring device shown in FIG. 1 includes a capture sheet 22 for capturing foreign matter 20 adhering to the surface of the wafer 16 and a foreign matter 2 captured by the capture sheet 22.
A foreign matter inspection device for detecting 0. FIG.
Then, the light emitting element 24a and the light receiving element 24 are used as foreign matter inspection devices.
b, an optical detection device 24 using reflected light or scattered light is used, but other types of optical or electric devices such as a visual inspection device such as an image processing type and a detection device using electromagnetism are used. It is also possible to use a target foreign matter detection device. For example, even when an appearance inspection device using pattern comparison of images is used as the foreign material inspection device, the foreign material 20 captured on the capture sheet 22 having no or little unevenness may be detected. 20 can be detected, and the effect of improving the processing capacity (throughput) can be obtained.

The capture sheet 22 has on its surface a material capable of adsorbing or sucking and capturing foreign matter 20 adhering to the surface of the wafer 16. That is, the capturing sheet 22 can capture the foreign matter 20 on its surface by physical adhesion, Coulomb force, intermolecular force, atomic force, magnetic force, and the like. For example, the capture sheet 22 can be realized by using a known semiconductor tape having a surface coated with an adhesive. In this case, it is preferable to use a non-UV acrylic adhesive so as not to chemically affect the pattern 18 on the surface of the substrate such as the wafer 16.

The capture sheet 22 is not primarily intended to remove the foreign matter 20 on the surface of the substrate such as the wafer 16, but captures the foreign matter 20 for detecting and monitoring the foreign matter 20 attached to the substrate. The main purpose is to use a pressure-sensitive adhesive that is not
Does not necessarily need to be strong enough to capture almost all of Therefore, the problem that the adhesive remains on the substrate surface is less likely to occur. On the other hand, a certain percentage of foreign matter 20
Therefore, the substrate surface and the capture sheet 22 need to be captured.
When the foreign matter 20 is captured by direct contact with the substrate, the force for bringing the capture sheet 22 into close contact with the substrate is required to be within a predetermined range. This range varies depending on the pattern 18 applied to the surface of the substrate and the material used for the adhesive, and is preferably determined through experiments or the like so as to ensure that the foreign matter 20 is captured at a fixed rate.

A sheet provided with a material which can be temporarily or permanently charged or magnetized is a capture sheet 22.
It is also possible to use as. In this case, the substrate is preferably charged or magnetized with the opposite polarity to the charged or magnetized material prior to capture, and the foreign matter 18 is also charged or magnetized through the charged or magnetized substrate with the opposite polarity, It will be sucked by the capture sheet 22. Note that when capturing foreign matter on the substrate surface by charging or magnetizing, it is not always necessary to bring the capture sheet 22 into contact with the substrate such as the wafer 16. It is important that the gap between them is within a certain range.

The foreign object monitoring device 10 shown in FIG.
Long strip-shaped capture sheet 2 of the type provided with an adhesive material on its surface
2 is used. In this case, when the capturing sheet 22 is brought into contact with the wafer 16 at the capturing position to capture the foreign matter adhering to the surface of the wafer 16, the capturing sheet 22 is sent to an inspection position located a predetermined distance ahead. Then, at the inspection position, the foreign object 20 captured by the capture sheet 22 is detected by the optical detection device 24. on the other hand,
A new portion of the capture sheet 22 has been sent to the capture position, and this portion is used to capture foreign matter attached to the surface of the next wafer 16.

Next, a series of operations of the foreign object monitoring apparatus shown in FIG. 1 will be described in further detail with reference to FIGS. First, as shown in FIG. 2, a substrate (here, a wafer 16) on which processing such as pattern transfer, cleaning, and polishing has been performed by a processing apparatus 12 is processed by a transfer apparatus such as a robot arm 14. Device 12
Is transferred to the foreign matter monitoring apparatus 10 of the present invention, and the wafer 16 is positioned at the capture position. At this time, the capture sheet 22 is spaced above the wafer 16.

It is sufficient that the capture sheet 22 is disposed so that its capture surface is opposed to the surface of the wafer 16 where foreign matter needs to be detected. If it faces downward, it goes without saying that the capture sheet 22 is arranged below the wafer 16. As shown in FIG. 2, it is assumed that the pattern 18 has already been transferred to the surface of the wafer 16, the surface has irregularities, and the foreign matter 20 has adhered thereon. In such a case, due to the presence of the pattern 18 on the surface of the wafer 16, an optical detection device such as an optical sensor using reflected light or scattered light capable of detecting foreign substances at high speed can be used. It is difficult to directly detect the foreign matter 20 attached to the surface. Further, even in such a case, if a visual inspection device using image processing is used, foreign matter inspection can be performed, but there is a disadvantage that processing ability is slow. Therefore, in the foreign matter monitoring technique of the present invention, after the foreign matter 20 on the surface of the wafer 16 is captured by the capture sheet 22, the foreign matter captured by the capture sheet 22 is inspected to inspect the foreign matter on the wafer 16. In the illustrated embodiment, the capture sheet 22 is a long strip-shaped sheet. However, it is needless to say that a single-sheet sheet having an area capable of covering the entire wafer 16 can be used.

As shown in FIG. 3, the capture sheet 22 disposed above the wafer 16 is moved downward and brought into contact with the wafer 16. The surface of the capture sheet 22 is provided with a foreign material capture layer utilizing adhesive force, Coulomb force, and intermolecular force, and the foreign material 20 on the wafer 16 is captured by the foreign material capture layer. In the case where a foreign substance capturing layer using a field such as Coulomb force is provided, the wafer 16
It is not necessary to bring the capture sheet 22 and the capture sheet 22 into contact with each other, and the foreign matter 20 on the surface of the wafer 16 can be suctioned and captured by the capture sheet 22 only by bringing the capture sheet 22 into close proximity. Here, when the foreign matter 20 is captured by the capture sheet 22, it is apparent that there is a correspondence between the position of the foreign matter on the wafer 16 and the position of the foreign matter on the capture sheet 22.

Next, as shown in FIG. 4, the capture sheet 22 is moved upward to be separated from the surface of the wafer 16. At this time, a predetermined positional relationship is maintained between the wafer 16 and a portion on the capture sheet 22 that captures the corresponding foreign matter 20. Lastly, the capture sheet 22 is sent forward by a predetermined distance to capture the foreign matter 20 corresponding to the wafer 16.
The upper part is positioned at the inspection position in FIG. Then, the foreign matter 20 captured by the capture sheet 22 is detected at this inspection position by scanning the optical detection device 24 on the capture sheet 22. At this time, it is possible to acquire data on the position, quantity, size, type (can be identified from the amount of reflected light, etc.) regarding the foreign matter 20. In addition, since a predetermined relationship is maintained between the position coordinates on the wafer 16 and the detection position coordinates at the inspection position, the foreign matter originally falls on the surface of the wafer 16 from the position of the foreign matter 20 on the capture sheet 22. Where it was. Here, the foreign matter 2 on the capture sheet 22 is captured only after the foreign matter 20 attached to the surface of the wafer 16 is captured.
0, but before the foreign matter 20 on the surface of the wafer 16 is captured, the foreign matter 20 on the capture sheet 22 is detected.
The foreign matter 20 increased before and after capturing the foreign matter 20 on the surface of the wafer 16 may be recognized as a newly captured foreign matter, that is, the foreign matter 20 on the surface of the wafer 16. In this case, it is possible to remove the influence of the foreign matter that has been attached to the capture sheet 22 in advance on the detection of the foreign matter on the surface of the wafer 16. Therefore, the capture sheet 22 can be reused.

On the other hand, a new portion of the capture sheet 22 has been moved to the capture position, and the foreign matter 2 adhering to the surface of the next wafer 16 transferred from the process apparatus 12 has been moved.
0 is captured in this part. In this manner, the foreign substance inspection of the wafer 16 is continuously performed on-line, and it is determined whether the wafer 16 is acceptable based on predetermined criteria regarding the position, quantity, size, type, etc. of the foreign substance. Judge.

Further, by observing the transition of the position, quantity, size, etc. of the foreign substance over time, the process equipment 12
, And performs operation control such as adjustment of operation parameters and stop of operation. In the embodiment illustrated in FIGS. 1 to 4, the capturing sheet 22 is turned over by a roller (not shown) or the like, and the surface on which the foreign matter 20 is captured, that is, the lower surface of the capturing sheet 22 is directed upward. The foreign substance 20 captured by the capture sheet 22 is detected by a foreign substance inspection device provided above the reference sheet 22. However, after the capture sheet 22 is moved in the horizontal direction without being inverted, foreign matter can be detected by a foreign matter inspection device that is located below the capture sheet 22 and is arranged to emit light upward. .

It is also possible to use a transparent sheet as the capture sheet 22 and detect the foreign material captured by the capture sheet 22 from the side opposite to the surface on which the foreign material 20 is captured.

[0030]

As described above, according to the present invention, in order to detect foreign matter on the surface of a substrate such as a wafer, foreign matter captured on a capture sheet having no irregularities on the surface is detected. Therefore, the foreign matter can be detected by the foreign matter inspection device without being affected by the pattern transferred to the wafer.

Further, since it is possible to use an optical or electric detecting device such as an optical sensor which is simple and has a high processing capability, it is possible to perform a foreign substance inspection of a processed substrate online. Furthermore, when conducting a foreign substance inspection online, the detection device can be scanned on the substrate to detect the quantity, size, position, and type of the foreign substance. In addition, when the number of foreign substances exceeding a certain number or size is detected by monitoring the transition of the number of foreign substances, the operation control of the process device can be performed, and the yield of the product substrate can be controlled. Can be improved.

In addition, according to the present invention, the foreign matter on the substrate is captured by the foreign matter capturing sheet, and as a result, the foreign matter on the substrate is removed, so that the foreign matter attached in the process immediately before the inspection affects the next process. And the effect of improving the product yield is also achieved.

[Brief description of the drawings]

FIG. 1 is a simplified perspective view showing an overall configuration of an embodiment of a foreign substance monitoring device according to the present invention.

FIG. 2 is a schematic diagram showing a series of operations of the foreign object monitoring device shown in FIG.

FIG. 3 is a schematic view showing a series of operations of the foreign object monitoring device shown in FIG. 1;

FIG. 4 is a schematic view showing a series of operations of the foreign object monitoring device shown in FIG. 1;

[Description of Signs] 10 Foreign matter monitoring device 12 Process device 16 Wafer 20 Foreign material 22 Capture sheet 24 Optical detection device 24a Light emitting device 24b Light receiving device

Claims (9)

[Claims] 1. A capture sheet for contacting or approaching the surface of a transferred substrate to capture foreign substances on the substrate surface, and a foreign substance captured by the capture sheet to detect foreign substances on the substrate surface And a foreign matter inspection device for detecting a foreign matter. 2. The foreign matter monitoring device according to claim 1, wherein said foreign matter inspection device comprises an optical or electrical foreign matter inspection device. 3. The foreign matter monitoring device according to claim 1, wherein the capturing sheet captures the foreign matter by any one of an adhesive force, a Coulomb force, and an intermolecular force. 4. The foreign matter inspection device detects foreign matter on the capture sheet before and after the foreign matter on the substrate surface is captured by the capture sheet, and detects foreign matter that has increased after capture in the capture sheet as compared to before capture. The foreign matter monitoring device according to claim 1, wherein the foreign matter monitoring device is configured to recognize the foreign matter as a foreign matter on the substrate surface. 5. A foreign matter inspection for bringing a capture sheet into contact with or approaching a surface of a substrate that has been processed in a process apparatus, capturing foreign matter on the substrate surface by the capture sheet, and detecting foreign matter on the substrate surface. A foreign matter monitoring method, wherein the foreign matter captured on the capture sheet by an apparatus is detected. 6. The foreign matter monitoring method according to claim 5, wherein the foreign matter inspection device detects at least one of the quantity, size, position, and type of the foreign matter. 7. The foreign matter monitoring method according to claim 6, wherein, based on a detection result of the foreign matter inspection device, it is determined whether or not the substrate is allowable or operation control of the process device is performed. . 8. The foreign matter monitoring method according to claim 5, wherein the capturing sheet captures the foreign matter by any one of an adhesive force, a Coulomb force, and an intermolecular force. 9. The foreign matter inspection device detects foreign matter on the capture sheet before and after the foreign matter on the substrate surface is captured by the capture sheet, and detects foreign matter that has increased after capture in the capture sheet as compared to before capture. 6. The foreign matter monitoring method according to claim 5, wherein the foreign matter is recognized as a foreign matter on the substrate surface.