KR20240015573A - Foreign matter determination method and lithography apparatus - Google Patents

Abstract

The method includes a first detection step of detecting first light in a first wavelength region scattered by a foreign substance on a surface to be inspected to be inspected, a second detection step of detecting second light in a second wavelength region different from the first wavelength region scattered by the foreign substance, and a first determination step of determining an influence of the foreign substance. In the first determination step, determination is performed using a first determination method based on at least one of intensity and scattering range of the scattered light detected in the first detection step and the second detection step, and the first determination method is a determination method according to a type of the foreign substance.

Description

Foreign matter determination method and lithography apparatus {FOREIGN MATTER DETERMINATION METHOD AND LITHOGRAPHY APPARATUS}

The present invention relates to a foreign matter determination method and lithography apparatus.

In the manufacturing process of semiconductor devices, liquid crystal display devices, etc., there is a method of detecting foreign matter by irradiating light to a surface to be inspected. The detected foreign matter is judged based on the detection result, and if it is judged to require removal, it is removed by the removal means. Additionally, as disclosed in Japanese Patent Publication No. 2020-204579, there is a method of irradiating light of three or more different wavelengths to the inspection surface and determining the type of foreign matter based on the reflectance.

Here, the degree of influence on the processing performed on the inspection object including the inspected surface, which is the object of determining the foreign matter, is related not only to the type of the foreign matter but also to the size of the foreign matter. Therefore, it is desirable to determine the degree of influence of the foreign matter by considering the size of the foreign matter using a determination method according to the type of foreign matter.

The purpose of the present invention is to provide a foreign matter determination method that is advantageous for determining the degree of influence of foreign matter.

In order to achieve the above object, a foreign matter determination method as one aspect of the present invention includes a first detection step of detecting first light in a first wavelength region scattered by a foreign matter on an inspection surface of an inspection object, and a second detection process for detecting second light in a second wavelength range different from the first wavelength range scattered by the first wavelength range, and a first determination process for determining the degree of influence of the foreign matter, in the first determination process. , the determination is made using a first determination method based on at least one of the intensity and scattering range of the scattered light detected in the first detection process and the second detection process, and the first determination method is a determination method according to the type of the foreign matter. It is characterized by being.

Further features of the invention will become apparent from the following description of exemplary embodiments (with reference to the accompanying drawings).

1 is a schematic diagram showing the configuration of a foreign matter determination device in the first embodiment.
Fig. 2 is a flowchart of foreign matter determination in the first embodiment.
Fig. 3 is a flowchart of foreign matter determination in the first embodiment.
Fig. 4 is a diagram showing the intensity of scattered light from the first light in the first embodiment.
Fig. 5 is a diagram showing the intensity of scattered light by the second light in the first embodiment.
FIG. 6 is a diagram showing the ratio (intensity ratio) of the intensity of scattered light by the first light to the intensity of the scattered light by the second light in the first embodiment.
Fig. 7 is a diagram showing the scattering range of scattered light by the first light in the first embodiment.
Fig. 8 is a diagram showing the scattering range of light scattered by the second light in the first embodiment.
FIG. 9 is a diagram showing the difference (scattering range difference) from the scattering range of the scattered light by the first light based on the scattering range of the scattered light by the second light in the first embodiment.
Fig. 10 is a flowchart showing the determination method for scattering foreign substances in the first embodiment.
Fig. 11 is a flowchart showing the determination method for non-scattering foreign substances in the first embodiment.
Fig. 12 is a schematic diagram showing the configuration of a projection exposure apparatus in the second embodiment.
Fig. 13 is a flowchart of a method for manufacturing an article according to the third embodiment.

EMBODIMENT OF THE INVENTION Below, embodiment of this invention is described based on the attached drawings. In addition, the following embodiments do not limit the invention according to the claims. Although a plurality of features are described in the embodiment, it is not limited that all of these features are essential to the invention, and the plurality of features may be arbitrarily combined. In addition, in the accompanying drawings, the same or similar components are assigned the same reference numerals, and duplicate descriptions are omitted.

In addition, in this specification and the accompanying drawings, the direction is basically shown by an It is done. However, if there is an XYZ coordinate system described in each drawing, that coordinate system takes priority.

Hereinafter, the specific configuration of each embodiment will be described.

<First embodiment>

Fig. 1 is a schematic diagram showing the configuration of the foreign matter determination device 100 in this embodiment. The foreign matter determination device 100 is disposed in, for example, a projection exposure device that exposes a pattern of an original plate (mask, reticle) to a substrate through a projection optical system using light irradiated by an illumination optical system. Then, foreign matter is detected on the surface of the original plate, the holding portion holding the original plate, the substrate, or the substrate holding portion holding the substrate. However, the foreign matter determination device 100 is not limited to its arrangement with respect to the projection exposure device. For example, the foreign matter determination device 100 may be disposed in a drawing device that draws on a substrate using an electron beam, an ion beam, or the like, and forms a pattern on the substrate. Additionally, the foreign matter determination device 100 may be disposed in another lithography device, for example, an imprint device that forms a pattern on a substrate by molding an imprint material on a substrate with a mold. Alternatively, the foreign matter determination device 100 may be placed in another device that processes substrates such as semiconductor wafers and glass plates, such as an ion implantation device, a developing device, an etching device, a film forming device, an annealing device, a sputtering device, or a vapor deposition device. Additionally, the foreign matter determination device 100 may be placed in a flattening device that flattens the composition on the substrate using a flat plate.

The foreign matter determination device 100 includes a light transmitting unit 1 that projects light 8 toward the inspection surface, a detection unit 2 that detects scattered light 7 from the inspection surface, and a wavelength filter 12. It is provided with a storage unit 15, a determination unit 16 that determines foreign matter on the inspection surface based on the detection result of the detection unit 2, and a transmission unit 20. Here, for example, when the light transmitting portion 1 is disposed in a projection exposure apparatus, the light transmitting portion 1 may be a light source of the projection exposure apparatus. In this case, the transmitted light 8 becomes exposure light. The detection unit 2 includes a light receiving sensor 10 that detects the scattered light 7, and a lens 11 that forms an image of the scattered light 7 on the light receiving sensor 10.

In addition, the determination unit 16 not only determines foreign matter on the inspected surface, but may also perform control as a control unit of the foreign matter determination device 100, such as a projection exposure device in which the foreign matter determination device 100 is disposed. Control of the substrate processing device may be performed simultaneously. The storage unit 15 stores the detection result detected by the detection unit 2. The transmission unit 20 transmits the information determined by the determination unit 16 to the display control unit (not shown). The display control unit controls the display of the display unit (not shown) based on the transmitted information. For example, text such as "Detected foreign matter requiring removal" is displayed on the display unit, and the user can determine the degree of influence of the detected foreign matter.

The wavelength filter 12 is configured to enable switching of insertion and emission over the optical path between the surface to be inspected and the detection unit 2, and selects light in a predetermined wavelength range among the scattered light 7 reaching the detection unit 2 from the surface to be inspected. It is a filter that transmits (ultraviolet light, infrared light, etc.) and absorbs or reflects others. Here, this wavelength filter 12 is a filter that can move between the position A in the optical path of the scattered light 7 and the position A' outside the optical path of the scattered light 7 detected by the detection unit 2.

When the wavelength filter 12 moves to position A' outside the optical path of the scattered light 7, the light detected by the detection unit 2 does not pass through the wavelength filter 12, so the light is the same as the transmitted light 8. It becomes (1st light). On the other hand, when the wavelength filter 12 moves to position A in the optical path of the scattered light 7, the light detected by the detection unit 2 passes through the wavelength filter 12. Accordingly, the light detected by the detection unit 2 is light (second light) transmitted by the transmitted light 8 through the wavelength filter 12 for a predetermined wavelength range. However, the wavelength filter 12 only needs to be able to transmit the light transmitted from the light transmitting portion 1 in a predetermined wavelength region, and is not limited to the arrangement location shown in FIG. 1. For example, the wavelength filter 12 may be disposed between the light transmitting portion 1 and the inspected surface at a position where only a predetermined wavelength range of the transmitted light 8 can be transmitted.

The transmitted light 8 from the light transmitting portion 1 is projected onto the inspection area of the member 3 having the inspected surface. The member 3 is, for example, surface-polished glass. Then, the scattered light 7 scattered by the foreign matter on the inspection surface present in the inspection area to which the transmitted light 8 is projected is detected by the detection unit 2, and the storage unit 15 detects the detection unit 2. Remember the results. The determination unit 16 determines the type of foreign matter based on the detection result by the detection unit 2 stored in the storage unit 15, and uses a determination method (first determination method) according to the determined type of foreign substance. Considering the size of the foreign matter, determine the degree of influence of the foreign matter. Here, the types of foreign matter in this embodiment refer to scattering foreign matter that easily scatters light and non-scattering foreign matter that hardly scatters light.

In addition, when inspecting the entire upper surface side of the member 3, the member 3 can be moved within the XY plane.

In this embodiment, it is assumed that there are three types of foreign substances (4 to 6) in the inspection area. The foreign material 4 is a solid scattering foreign material, the foreign material 5 is a non-scattering foreign material such as oil, and the foreign material 6 is a solid scattering foreign material with lower scattering properties than the foreign material 4. Here, the scattering foreign matter is a foreign matter that has an uneven shape and has a high light scattering property, for example, a solid. On the other hand, a non-scattering foreign matter is a foreign matter that has a shape close to flat and has a low light scattering property, for example, a liquid.

The detection unit 2 detects the intensity and scattering range of the first light and the second light, respectively, of the scattered light 7 scattered by the foreign matter on the inspection surface. Since the intensity of the scattered light 7 from the foreign object is high (large amount of light), the position where the peak of the intensity of the scattered light 7 is detected can be determined to be the position of the foreign object.

Here, determination of the size of the foreign matter will be explained. In the case of a highly scattering foreign material such as the foreign material 4, the intensity of the scattered light 7 changes depending on the size of the foreign material, so the size of the foreign material can be determined based on the intensity of the scattered light 7. On the other hand, in the case of a non-scattering foreign material such as the foreign material 5, the intensity of the scattered light 7 does not correspond to the size of the foreign material, and therefore the size of the foreign material cannot be determined from the intensity of the scattered light 7. Therefore, in the case of non-scattering foreign matter, the size of the foreign matter is determined based on the scattering range of the scattered light 7. The scattering range is the number of pixels of the sensor when the light receiving sensor 10 detects the scattered light 7. The size of the foreign matter can be determined based on this scattering range. Even if the foreign matter is a scattering foreign matter, if the scattering property is low, such as the foreign matter 6, the intensity of the scattered light 7 may not correspond to the size of the foreign matter. Foreign substances with low scattering properties are specifically, for example, foreign substances with a thin, flat shape or an anisotropic shape. Therefore, if it is a low-scattering foreign material such as the foreign material 6 and the intensity of the scattered light 7 is low and the size of the foreign material cannot be determined based on the intensity of the scattered light 7, the scattering range of the scattered light 7 By determining based on , the size of the foreign matter can be determined.

The memory unit 15 stores the position at which the peak of the scattered light 7 detected by the detection unit 2 was detected (position of the foreign object), the intensity of the scattered light 7, and the scattering range of the scattered light 7. The determination unit 16 determines the type of the foreign object based on the information (detection result of the detection unit 2) stored in the storage unit 15, and determines the size of the foreign object by a determination method according to the determined type of the foreign substance. Consider and determine the degree of influence of foreign matter. For example, it is assumed that the foreign matter determination device 100 is disposed in a projection exposure apparatus and detects foreign matter on an original plate (mask) on which a pattern for transfer to a substrate is formed. In this case, if there is a large foreign matter on the original plate, it will adversely affect the result of the exposure process. In addition, the degree of influence on the exposure process varies depending on the type of foreign matter, and when a scattering foreign matter such as a solid is on the original plate, the foreign matter significantly blocks the exposure light, adversely affecting the result of the exposure process. However, when a non-scattering foreign matter such as oil is on the original plate, it blocks the exposure light, but since the amount of blocking the exposure light is small compared to the scattering foreign material, the effect on the result of the exposure process is relatively small. In this way, if there is a large scattering foreign matter, it is desirable to stop the exposure process and remove the foreign matter because it has a great influence on the result of the exposure process. However, in the case of a small non-scattering foreign matter, it has an effect on the result of the exposure process. Because this is relatively small, there is no need to stop the exposure process. That is, it becomes possible to determine whether removal of the foreign material is necessary by considering the type of foreign material and the size of the foreign material and determining the degree of influence of the foreign material using a determination method according to the determined type of foreign material.

In this embodiment, the foreign matter detected by the detection unit 2 is determined to be one of three types: X rank, Y rank, and Z rank depending on the degree of influence. Rank X is the case where no foreign matter is detected. Rank Y is a case where a foreign substance judged to be unlikely to have a significant impact is detected. Z rank is a case where a foreign substance judged to be highly likely to have a significant impact is detected.

For example, when the foreign matter determination device 100 is a projection exposure device, a foreign matter that causes resolution defects during exposure is a foreign matter that is likely to have a significant impact and is determined to be Z rank. On the other hand, foreign matter that is unlikely to cause resolution defects during exposure is a foreign matter that is unlikely to have a significant effect and is determined to be Y rank.

When a Z-rank foreign matter is detected, it is desirable to stop the exposure process and remove the foreign matter. However, in this embodiment, foreign matter is judged into three ranks, but this is not limited to the example of this embodiment, and the user may freely set them.

For example, if the degree of influence of a foreign object is determined based only on the intensity of the scattered light 7, as described above, in the case of a non-scattering foreign material or a low scattering foreign material, the intensity of the scattered light 7 does not change depending on the size of the foreign material. Therefore, there is a possibility of misjudging the influence of foreign matter.

Accordingly, in the present embodiment, the type of foreign matter on the surface to be inspected is determined based on at least one of the intensity and scattering range of the scattered light 7 caused by two types of light with different wavelength regions, and the type of foreign matter is determined according to the determined type of foreign matter. The degree of influence of foreign matter is determined using a determination method.

In this embodiment, the first light is light in a first wavelength region that includes the wavelength region of visible light and the wavelength region of ultraviolet light, and the second light is light in the wavelength region of ultraviolet light but does not include the wavelength region of visible light. It is explained as light in the wavelength range. For example, the light of a mercury lamp used as a light source of an exposure apparatus is first light (first wavelength range) that includes the wavelength range of visible light and the wavelength range of ultraviolet light. By disposing the wavelength filter 12 in the optical path between the surface to be inspected and the detection unit 2, the first light is changed into the second light (second wavelength region) by the wavelength filter 12, and the detection unit 2 2 Detect scattered light (7) from light.

2 and 3 are flowcharts of foreign matter determination in this embodiment. First, it is determined whether the scattered light 7 caused by the first light that did not pass through the wavelength filter 12 was detected (S101). When the scattered light 7 caused by the first light that did not pass through the wavelength filter 12 is not detected, the wavelength filter 12 is placed at a position other than the optical path of the scattered light 7 detected by the detection unit 2 (S102) . In step S101, when the scattered light 7 by the first light that did not pass through the wavelength filter 12 is detected, it is determined whether the scattered light 7 by the second light that did not pass through the wavelength filter 12 was detected. (S103). When the scattered light 7 caused by the second light through the wavelength filter 12 is not detected, the wavelength filter 12 is placed at a position in the optical path of the scattered light 7 detected by the detection unit 2 (S104). Then, the light transmitting unit 1 projects the transmitted light 8 toward the inspected surface (S105), the detecting unit 2 detects the scattered light 7 (S106), and the detection result of the detecting unit 2 in step S106 Based on this, it is determined whether there is a foreign substance on the inspection surface (S107). In addition, step S106 becomes a first detection process when detecting the scattered light 7 by the first light, and a second detection process when detecting the scattered light 7 by the second light. Here, the scattered light 7 detected by the detection unit 2 in step S106 detects both scattered light from a location on the inspection surface where no foreign matter exists and scattered light scattered by the foreign matter.

However, since the intensity of the scattered light scattered by the foreign matter is higher than that of the scattered light from a location where the foreign matter does not exist, the detection unit 2 can detect the foreign matter. If there is a foreign substance on the inspection surface, information on one or more foreign substances detected on the inspection surface is stored (S108), and the process returns to step S101. The information stored in step S108 is the position at which the peak of the scattered light 7 detected by the detection unit 2 is detected (position of the foreign matter), the intensity of the scattered light 7, and the scattering range of the scattered light 7. If there is no foreign matter on the inspection surface in step S107, the process returns to step S101.

When the scattered light 7 is detected through the wavelength filter 12 in step S103, it is determined whether or not the foreign matter was detected both when it passed through the wavelength filter 12 and when it did not pass through the wavelength filter 12 (S109). If no foreign matter is detected at all, the process ends with the assumption that there is no foreign matter in the inspection area on the inspection surface. In step S109, when a foreign matter is detected both when passing through the wavelength filter 12 and when not passing through the wavelength filter 12, when the scattered light 7 is detected through the wavelength filter 12 and when the scattered light 7 is detected not passing through the wavelength filter 12 ( 7) Corresponds to the information on the foreign object when detected (S110). Then, it is determined whether there is a foreign substance determined to have a high possibility of having a significant effect requiring removal (Z rank) (S111). Additionally, step S111 is a second determination process that determines whether removal of the foreign matter is necessary based on the determination result of the determination unit 16. If there is no foreign object determined to have a high probability of having a large impact requiring removal (Z rank), it is determined whether there is information for which a rank for each degree of influence has not been determined among the stored information about the foreign material (S112). If there is no information among the stored foreign object information for which a ranking for each influence level has not been determined, the process ends. If there is information that has not been determined among the stored information about the foreign material, one piece of information that has not been determined is selected from the information about the stored foreign material (S113), and it is determined whether the selected foreign material is a scattering foreign material (S114). In the case of a scattering foreign matter, the foreign matter is determined by rank according to the degree of influence on the treatment performed by the inspection object by the scattering foreign matter determination method and stored (S115). If the foreign matter is not a scattering foreign matter, the foreign matter is judged in rank according to its influence on the treatment performed by the inspection object using the non-scattering foreign matter determination method and stored (S116). Additionally, steps S115 and S116 are the first determination processes for determining the degree of influence of foreign substances.

The transmitting unit 20 transmits information regarding the degree of influence of the foreign object on the processing performed by the inspection target determined by the determination unit 16 to the display control unit, and the display control unit transmits information regarding the degree of influence of the foreign object on the processing performed by the inspection target received from the transmitting unit 20. The display of the display unit is controlled based on information regarding the degree of influence on processing (S117). Then, the process returns to step S111. If it is determined in step S111 that there is a foreign matter that is determined to be highly likely to have a significant effect requiring removal, the foreign matter is removed (S118) and the process ends.

Here, determination of the type of foreign matter in step S114 will be explained. FIG. 4 is a diagram showing the intensity of scattered light 7 by the first light in this embodiment. When the detection unit 2 detects the scattered light 7 caused by the first light that did not pass through the wavelength filter 12, the intensity of the scattered light 7 is a for the foreign matter 4, b for the foreign matter 5, and (6) is c. Since the foreign material 4 is a solid, highly scattering foreign material, the intensity of the scattered light 7 from the first light is high. Since the foreign matter 5 is a non-scattering foreign matter such as oil, the intensity of the scattered light 7 from the first light is low. Since the foreign material 6 is a solid scattering foreign material with a low scattering property, the intensity of the scattered light 7 is lower than that of the foreign material 4.

FIG. 5 is a diagram showing the intensity of scattered light 7 by the second light in this embodiment. When the detection unit 2 detects the scattered light 7 caused by the second light through the wavelength filter 12, the intensity of the scattered light 7 is d for the foreign matter 4, e for the foreign matter 5, and foreign matter ( 6) is f. Since the foreign material 4 is a solid, highly scattering foreign material, the intensity of the scattered light 7 is high regardless of the type of light (first light, second light). Since the foreign matter 5 is a non-scattering foreign matter such as oil, the intensity of the scattered light 7 by the second light, which is ultraviolet light, is compared to the intensity of the scattered light 7 by the first light, which is a mixed light of visible light and ultraviolet light. It gets very low. Since the foreign material 6 is a solid scattering foreign material, the intensity of the scattered light 7 is obtained regardless of the type of light (first light, second light), but since the scattering property is low, the foreign material 4 is similar to that of the first light. ) Compared to ), the intensity of scattered light (7) is low.

FIG. 6 is a diagram showing the ratio (intensity ratio) of the intensity of the scattered light 7 by the first light to the intensity of the scattered light 7 by the second light in the present embodiment. The ratio of the intensity of the scattered light 7 by the first light to the intensity of the scattered light 7 by the second light is A = a/d for the foreign matter 4 and B = b/e for the foreign matter 5, respectively. , the foreign matter (6) is C=c/f. Since the intensity of the scattered light 7 is not significantly different when the foreign material 4 and the foreign material 6, which are scattering foreign materials, pass through the wavelength filter 12 and when it does not pass through the wavelength filter 12, the intensity ratio of the scattered light 7 (A, C) is small. On the other hand, the foreign matter 5, which is a non-scattering foreign matter, has a high intensity when not passing through the wavelength filter 12, and has a low intensity when passing through the wavelength filter 12, and is determined by the presence or absence of the wavelength filter 12 in the detection unit ( The intensity of the scattered light (7) detected by 2) varies greatly. Therefore, the foreign matter 5 has a large intensity ratio B of the scattered light 7. In this way, it is possible to determine whether the foreign matter is a scattering foreign matter or a non-scattering foreign matter based on the intensity ratio of the scattered light 7 when it passes through the wavelength filter 12 and when it does not pass through it.

The user sets in advance an intensity threshold P (type determination threshold) for determining whether the foreign material is a scattering foreign material or a non-scattering foreign material. The intensity threshold P may be set based on the results of foreign matter detection performed experimentally in advance by the user, or, if it can be estimated from a design value or the like, may be set based on a design value or the like.

In the case of FIG. 6, the determination unit 16 determines that the intensity ratio (A, C) of the scattered light 7 of the foreign substance 4 and the foreign substance 6 is less than or equal to the intensity threshold value P. ) is judged to be a scattering foreign body. Additionally, since the intensity ratio B of the scattered light 7 of the foreign material 5 is greater than the intensity threshold P, the foreign material 5 is determined to be a non-scattering foreign material. In addition, in this embodiment, the scattered light 7 is judged to be scattering when it is below the intensity threshold P, and non-scattering when it is greater than the intensity threshold P. However, it is judged to be scattering when it is smaller than the intensity threshold P, and non-scattering when it is above the intensity threshold P. It may be dispersive. Here, the intensity of the scattered light 7 caused by the second light (ultraviolet light) cannot be detected through the wavelength filter 12, and when the value becomes 0, the intensity ratio of the scattered light 7 becomes infinite. In such a case, a method of determining whether the foreign matter is a scattering foreign matter or a non-scattering foreign matter based on the scattering range of the scattered light 7, which will be described later, is adopted.

Regarding the determination of the type of foreign matter in step S114, a method of determining based on the intensity ratio of the scattered light 7 has been described. However, the type of the foreign matter may be determined based on the scattering range of the scattered light 7. FIG. 7 is a diagram showing the scattering range of the scattered light 7 by the first light in the present embodiment. When the detection unit 2 detects the scattered light 7 caused by the first light that did not pass through the wavelength filter 12, the scattering range of the scattered light 7 is g for the foreign matter 4, h for the foreign matter 5, The foreign body (6) is i. Since the scattering range of the scattered light 7 by the first light changes depending on the size of the foreign object, the size of the foreign object can be determined based on the detection result of the scattering range of the scattered light 7 by the first light.

Fig. 8 is a diagram showing the scattering range of the scattered light 7 by the second light in the present embodiment. When the detection unit 2 detects the scattered light 7 caused by the second light through the wavelength filter 12, the scattering range of the scattered light 7 is j for the foreign matter 4, k for the foreign matter 5, and k for the foreign matter 5. (6) is l. Since the foreign matter 4 is a scattering foreign matter, the scattering range of the scattered light 7 does not change depending on the type of light (first light, second light). Since the foreign matter 5 is a non-scattering foreign matter such as oil, the scattering range of the scattered light 7 by the second light, which is ultraviolet light, is the scattering range of the scattered light 7 by the first light, which is a mixed light of visible light and ultraviolet light. It becomes smaller in comparison. Since the foreign matter 6 is a scattering foreign matter, the scattering range of the scattered light 7 does not change depending on the type of light (first light, second light).

FIG. 9 is a diagram showing the difference (scattering range difference) from the scattering range of the scattered light 7 by the first light based on the scattering range of the scattered light 7 by the second light in the present embodiment. Based on the scattering range of the scattered light 7 by the second light, the difference with the scattering range of the scattered light 7 by the first light is D = g-j for the foreign matter 4 and E = h-k for the foreign matter 5. , the foreign body (6) is F=i-l. Since the scattering range of the scattered light 7 is not significantly different between the foreign matter 4 and the foreign matter 6, which are scattering foreign substances, when it passes through the wavelength filter 12 and when it does not pass through the wavelength filter 12, the scattering range difference (D, F) is small. On the other hand, the foreign matter 5, which is a non-scattering foreign matter, has a large scattering range when it does not pass through the wavelength filter 12, and has a small scattering range when it passes through the wavelength filter 12, and varies depending on the presence or absence of the wavelength filter 12. The scattering range of the scattered light 7 detected by the detection unit 2 changes significantly. Therefore, the foreign matter 5 has a large scattering range difference E of the scattered light 7. Therefore, it is possible to determine whether the foreign matter is a scattering foreign matter or a non-scattering foreign matter based on the difference in the scattering range of the scattered light 7 when it passes through the wavelength filter 12 and when it does not pass through the wavelength filter 12.

The user sets a scattering range threshold T (type determination threshold) in advance to determine whether the foreign material is a scattering foreign material or a non-scattering foreign material. The scattering range threshold T may be set based on the results of foreign matter detection performed experimentally in advance by the user, or, if it can be estimated from a design value or the like, may be set based on a design value or the like.

In the case of FIG. 9, the determination unit 16 determines the difference between the foreign material 4 and the foreign material 6 in that the scattering range difference D, F between the scattered light 7 of the foreign material 4 and the foreign material 6 is less than or equal to the scattering range threshold T. (6) is judged to be a scattering foreign body. Additionally, since the scattering range difference E of the scattered light 7 of the foreign material 5 is greater than the scattering range threshold T, the foreign material 5 is determined to be a non-scattering foreign material. In addition, in this embodiment, when the scattering range difference of the scattered light 7 is less than the scattering range threshold T, it is determined to be scattering, and when it is greater than the scattering range threshold T, it is determined to be non-scattering. However, when it is smaller than the scattering range threshold T, it is judged to be scattering, and when it is smaller than the scattering range threshold T, it is determined to be scattering. When the value is T or higher, it may be non-scattering.

In this embodiment, an example of using the intensity ratio and scattering range difference of the scattered light 7 when determining the type of foreign matter has been explained. However, it is not necessary to use the intensity ratio of the scattered light 7 or the scattering range difference. For example, at least one of the intensity difference of the scattered light 7 and the scattering range ratio may be used to determine the type of foreign matter.

Here, a method in which the determination unit 16 in step S115 determines the scattering foreign matter by rank according to the degree of influence by the scattering foreign matter determination method will be described. Fig. 10 is a flowchart showing the determination method for scattering foreign substances in this embodiment. First, it is determined whether to select the intensity of the scattered light 7 as the determination target (S210). When the intensity of the scattered light 7 is selected as the determination target, it is determined whether the intensity of the scattered light 7 by the first light that did not pass through the wavelength filter 12 is more than the intensity threshold Q for scattering (S220) . If the intensity of the scattered light 7 is equal to or greater than the scattering intensity threshold Q, it is determined to be Z rank (S240), and the process ends. If the intensity of the scattered light 7 is less than the intensity threshold Q for scattering properties, the scattering range of the scattered light 7 is selected as the determination target, and it is determined whether the scattering range of the scattered light 7 is greater than or equal to the scattering range threshold R for scattering properties ( S230). If the scattering range of the scattered light 7 is greater than or equal to the scattering range threshold value R for scattering properties, it is determined to be Z rank (S240), and the process ends. If the scattering range of the scattered light 7 is less than the scattering range threshold R for scattering properties, it is determined to be Y rank (S250) and the process ends.

Here, the reason why the degree of influence of foreign matter is determined based on the scattering range when the intensity of the scattered light 7 is less than the scattering intensity threshold Q is explained. The fact that the intensity of the scattered light 7 is less than the intensity threshold Q for scattering means that the intensity of the scattered light 7 is low, and the scattered light 7 scattered by foreign substances and the scattered light 7 on the inspection surface can be distinguished. . In this case, if the size is derived from the intensity of the scattered light 7, an error occurs between the derived size of the foreign object and the actual size of the foreign material. Therefore, when the intensity of the scattered light 7 is less than the scattering intensity threshold Q, the degree of influence of the foreign matter is determined based on the scattering range of the scattered light 7.

Next, a description will be given of how the determination unit 16 in step S116 determines the non-scattering foreign matter in ranks according to the degree of influence by the non-scattering foreign matter determination method. Fig. 11 is a flowchart showing the determination method for non-scattering foreign substances in this embodiment. First, the scattering range of the scattered light 7 is selected as a determination target (S310), and it is determined whether the scattering range of the scattered light 7 is greater than or equal to the scattering range threshold value S for non-scattering (S320). If the scattering range is greater than or equal to the non-scattering scattering range threshold S, it is determined to be Z rank (S330) and the process ends. If the scattering range is less than the non-scattering scattering range threshold S, it is determined to be Y rank (S340) and the process ends.

As described above, since the intensity of the scattered light 7 of a non-scattering foreign matter does not change depending on the size of the foreign matter, the size of the foreign matter cannot be determined based on the intensity of the scattered light 7. Therefore, in step S116, when non-scattering foreign matter is judged according to the degree of influence, the judgment is made based on the scattering range of the scattered light 7.

Here, the user prepares a threshold value for each type of foreign matter in advance. That is, the scattering intensity threshold Q and the scattering range threshold R as the first threshold that are the thresholds for determining the scattering foreign matter, and the non-scattering scattering range threshold as the second threshold that is the threshold for determining the non-scattering foreign matter. Set S.

The intensity threshold Q for scattering, the scattering range threshold R for scattering, and the scattering range threshold S for non-scattering may be set based on the results of foreign matter detection performed experimentally in advance by the user, or may be estimated from design values, etc. In this case, it may be set based on design values, etc.

As a result of the determination, if the detected foreign matter is Y rank, it is unlikely to have a significant influence. Therefore, for example, when the foreign matter determination device 100 is a projection exposure device, exposure is continued. If the detected foreign matter is Z rank, it is likely to have a significant impact, so the foreign matter on the inspection surface is removed. In addition, the detection unit 2 detects stray light from the surroundings along with the scattered light 7, but it is desirable to adjust the intensity threshold Q for scattering according to the change in the intensity of this stray light.

According to this embodiment, since the degree of influence of the foreign object is determined using a determination method according to the type of the foreign object, the degree of influence of the foreign object can be appropriately determined.

<Second Embodiment>

Fig. 12 is a schematic diagram showing the configuration of the projection exposure apparatus 200 in this embodiment. The projection exposure apparatus 200 in this embodiment applies the exposure light 80 from the light source 110 to project the pattern of the mask 30 (original plate) onto the substrate stage 32 through the projection optical system 14. It is transferred to the supported substrate 31. Here, the substrate 31 is, for example, a silicon wafer or a glass plate.

The mask 30 is mounted on the mask stage 17 (original plate stage). Here, since the mask 30 is a heavy member, it may bend in the -Z-axis direction due to its own weight. For this reason, a warp correction member 18 (optical member) is provided above the mask 30, and an airtight chamber 19 is provided between the warp correction member 18 and the mask 30. By adjusting the pressure of this airtight chamber 19, the mask 30 reduces warping in the -Z axis direction.

The projection exposure apparatus 200 in this embodiment has a foreign matter determination device of the same configuration as that in the first embodiment, and foreign matter detection and determination are performed in the same manner as in the first embodiment. In addition, the light transmitting portion 1 and the light transmitting light 8 in the first embodiment are the light source 110 and the exposure light 80 in the present embodiment. With this configuration, the exposure light 80 from the light source 110 can be used to detect foreign substances, and there is no need to provide a new light transmitting unit for detecting foreign substances.

Additionally, the detection unit 2 is preferably disposed near the warpage correction member 18. By arranging the detection unit 2 near the warpage correction member 18, the entire surface of the surface to be inspected can be inspected by moving the mask 30 by driving the mask stage 17 without providing a new driving unit. You can.

A portion of the exposure light 80 emitted from the light source 110 is scattered onto the surface of the bending correction member 18 on the light source 110 side, and the detection unit 2 is detected on the bending correction member 18 by the scattered light 7. Detect foreign substances. On the other hand, the exposure light 80 that is not scattered on the surface of the warp correction member 18 on the light source 110 side transfers the pattern of the mask 30 to the substrate 31 through the projection optical system 14.

In this embodiment, foreign matter is determined on the surface of the warp correction member 18 on the light source 110 side using the exposure light 80 from the light source 110. If a foreign matter exists on the warp correction member 18, it will affect the pattern transfer in the exposure process, so the foreign matter is determined and, if necessary, the foreign matter on the warp correction member 18 is removed. Additionally, by moving the mask stage 17, foreign matter on the entire surface of the warp correction member 18 can be detected. For example, when moving the mask stage 17 during exposure, foreign matter on the warp correction member 18 can be detected. The decision may be made together. In addition, in this embodiment, an example of determination of foreign matter on the bending correction member 18 disposed above the mask 30 has been described, but the object for which foreign matter determination is performed is not limited to the bending correction member 18. For example, foreign matter may be determined on another optical member disposed between the mask 30 and the light source 110. Alternatively, foreign matter may be determined on the surface of the mask 30 on the light source 110 side.

Additionally, foreign matter detection and determination may be performed, for example, when the mask stage 17 reciprocates during exposure processing. In this case, when the mask stage 17 moves to a predetermined position (during outward travel), the wavelength filter 12 is placed at a position A' outside the optical path of the scattered light 7 detected by the detection unit 2. When the mask stage 17 moves from a predetermined position to the original position (when returning), the wavelength filter 12 is placed at position A in the optical path of the scattered light 7 detected by the detection unit 2. By moving the wavelength filter 12 during the exposure process in this way, foreign matter can be detected and determined when the mask stage 17 is reciprocated during the exposure process.

Alternatively, when exposing a second shot area different from the first shot area, the wavelength filter 12 is placed at a position A' outside the optical path of the scattered light 7 detected by the detection unit 2 when exposing the first shot area. The wavelength filter 12 may be disposed at position A in the optical path of the scattered light 7 detected by the detection unit 2.

That is, the detection unit 2 detects the scattered light 7 by the first light when exposing the first shot area, and the scattered light 7 by the second light when exposing the second shot area different from the first shot area. 7) is detected. By moving the wavelength filter 12 in this way, foreign matter can be determined in parallel with the exposure process for the two shot areas.

As an example of performing foreign matter determination other than during exposure, it is preferable to perform it immediately after replacing the mask 30, for example. When replacing the mask 30, external air containing dust, etc. may flow in and cause foreign matter to adhere to the warp correction member 18. Therefore, it is preferable to inspect for foreign matter after replacing the mask 30 and before exposure processing. do. In addition, foreign matter determination can be performed without reducing productivity by performing foreign matter determination when performing calibration for alignment while moving the mask stage 17.

According to this embodiment, foreign matter on the mask 30 or the warpage correction member 18 of the projection exposure apparatus 200 can be detected and determined, and the influence of the foreign matter on the exposure process can be reduced. Additionally, in this embodiment, since the light source 110 can be used in the light transmitting part used for foreign matter determination, there is no need to provide a new light transmitting part for foreign matter determination. And, by performing foreign matter determination during calibration or exposure processing, the time for stopping production for foreign matter determination can be reduced. In addition, in this embodiment, an example of detection and determination of foreign matter on the mask 30 or the warpage correction member 18 is shown, but detection and determination of foreign matter on the substrate 31 or the substrate stage 32 are shown. It's okay too.

<Third embodiment>

This embodiment is characterized in that an article is manufactured using the foreign matter removal device described in the first and second embodiments.

Fig. 13 is a flowchart of the method for manufacturing an article according to this embodiment. Using the foreign matter determination device described in the first and second embodiments, a first detection process (S410) of detecting the first light in the first wavelength region scattered by the foreign matter on the inspection target surface of the lithography apparatus is performed. Then, a second detection process (S420) is performed to detect second light in a second wavelength range different from the first wavelength range scattered by the foreign matter. Thereafter, exposure is performed by the lithography apparatus using a determination method (first determination method) according to the type of foreign matter based on at least one of the intensity and scattering range of the scattered light detected in the first detection process and the second detection process. A determination process (S430) is performed to determine the degree of influence of the foreign matter on the processing. Then, a forming process (S440) of forming a pattern on a substrate using a lithography apparatus is performed, and a manufacturing process (S450) of manufacturing an article from the substrate on which the pattern was formed in the forming process is performed.

Products manufactured by this manufacturing method include, for example, semiconductor IC elements, liquid crystal display elements, color filters, MEMS, etc.

The formation process forms a pattern on a substrate, for example, by exposing a substrate (silicon wafer, glass plate, etc.) on which a photosensitive material is applied over a pattern material by a lithographic apparatus (exposure apparatus).

The manufacturing process includes, for example, development of a patterned substrate (photosensitive material), etching and resist stripping of the developed substrate, dicing, bonding, and packaging. According to this manufacturing method, higher quality products can be manufactured than before.

According to the present invention, it is possible to provide a foreign matter determination method that is advantageous for determining the degree of influence of a foreign matter.

Although the invention has been described with reference to exemplary embodiments, it should be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass equivalent structure and function with all such modifications.

This application claims the benefit of Japanese Patent Application No. 2022-119421 filed on July 27, 2022, which is hereby incorporated by reference in its entirety.

Claims (20)

A first detection process for detecting first light in a first wavelength region scattered by a foreign matter on the inspection surface of the inspection object;
a second detection process for detecting second light in a second wavelength range different from the first wavelength range scattered by the foreign matter;
A first determination process for determining the degree of influence of the foreign matter,
In the first determination process, a determination is made using a first determination method based on at least one of the intensity and scattering range of the scattered light detected in the first detection process and the second detection process,
The first determination method is a foreign matter determination method, characterized in that the first determination method is a determination method according to the type of the foreign matter. According to paragraph 1,
The determination method according to the type of foreign matter is characterized in that either the intensity or the scattering range of the scattered light is selected as a determination target according to the type of the foreign matter, and the determination is made based on a threshold value provided for each type of the foreign matter. Foreign matter determination method. According to paragraph 1,
In the first determination process, when it is determined that the foreign material is a scattering foreign material, the intensity or scattering range of the scattered light is compared with a first threshold for determining the degree of influence of the scattering foreign material to determine the degree of influence of the scattering foreign material. , and when it is determined that the foreign matter is a non-scattering foreign matter, the scattering range of the scattered light is compared with a second threshold value different from the first threshold value for determining the degree of influence of the non-scattering foreign matter, and the ratio A foreign matter determination method characterized by determining the degree of influence of scattering foreign matter. According to paragraph 1,
A foreign substance determination method comprising a second determination process for determining whether removal of the foreign substance is necessary based on the determination result of the first determination process. According to paragraph 1,
A foreign matter determination method, characterized in that, in the second detection process, a wavelength filter that changes the first wavelength region to the second wavelength region is disposed in the optical path. According to paragraph 1,
A foreign matter determination method, wherein the type of the foreign matter in the first determination step is determined as either a scattering foreign matter or a non-scattering foreign matter. According to paragraph 1,
The first judgment step is to obtain a difference or ratio between the intensity or scattering range of the scattered light by the first light with respect to the intensity or scattering range of the scattered light by the second light, and the obtained difference or ratio and the A foreign matter determination method characterized in that the type of foreign matter is determined by comparing a type determination threshold for determining the type of the foreign matter. According to paragraph 1,
A foreign matter determination method comprising a transmission step for transmitting information regarding the degree of influence of the foreign matter determined by the first judgment step. a detection unit that detects first light in a first wavelength range scattered by foreign matter on the inspection surface of the inspection target and second light in a second wavelength range different from the first wavelength range;
It has a determination unit that determines the degree of influence of the foreign matter,
A foreign matter determination device, wherein the determination unit makes a determination using a determination method according to the type of the foreign matter based on at least one of the intensity and scattering range of the scattered light detected by the detection unit. According to clause 9,
It has a wavelength filter that changes the first wavelength region into the second wavelength region,
A foreign matter determination device wherein the wavelength filter is disposed in an optical path when detecting the second light. According to clause 9,
A foreign matter determination device comprising a transmitting unit that transmits information regarding the degree of influence of the foreign matter determined by the determination unit. According to clause 11,
A foreign matter determination device, wherein the display control unit that receives information from the transmitter controls the display of the display unit based on the information regarding the degree of influence of the foreign matter received from the transmitter. It is a lithographic device that forms a pattern on a substrate,
First light in a first wavelength range scattered by foreign matter on the original plate on which the pattern is provided or an optical member between the original plate and the light transmitting portion that emits light, and a second wavelength area different from the first wavelength area a detection unit that detects the second light,
A determination unit that determines the degree of influence of the foreign matter on the exposure process performed by the lithography apparatus.
Have,
The lithography apparatus is characterized in that the determination unit makes a determination using a determination method according to the type of the foreign matter based on at least one of the intensity and scattering range of the scattered light detected by the detection unit. According to clause 13,
A lithography apparatus, wherein the optical member is a member for correcting warping of the original plate. According to clause 13,
A lithographic apparatus, wherein the detection unit is disposed near the optical member. According to clause 13,
The lithographic apparatus, wherein the light transmitting unit is a light source that emits exposure light for forming the pattern on the substrate. According to clause 13,
Detection of the scattered light by the first light is performed during a return trip when the disk moves to a predetermined position, and detection of the scattered light by the second light is performed during a return trip when the disk moves from a predetermined position to an original position. A lithographic apparatus, characterized in that carried out in. According to clause 13,
A lithography apparatus, characterized in that the detection of the scattered light by the detection unit is performed when calibrating an original stage holding the original plate or when performing exposure for forming the pattern on the substrate. According to clause 13,
The detection unit detects the scattered light by the first light when exposing a first shot area, and detects the scattered light by the second light when exposing a second shot area different from the first shot area. A lithographic device characterized in that. A first detection process of detecting first light in a first wavelength region scattered by a foreign matter on the inspection surface of the lithography apparatus,
a second detection process for detecting second light in a second wavelength range different from the first wavelength range scattered by the foreign matter;
a first determination process of determining the degree of influence of the foreign matter on exposure processing performed by the lithography apparatus;
After the first determination process, a forming process of forming a pattern on the substrate by the lithographic apparatus;
A manufacturing process of manufacturing an article from the substrate on which the pattern is formed in the forming process
Have,
In the first determination process, a determination is made using a first determination method based on at least one of the intensity and scattering range of the scattered light detected in the first detection process and the second detection process,
A method of manufacturing an article, characterized in that the first determination method is a determination method according to the type of the foreign matter.

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