Foreign object inspection device, exposure device, and method for manufacturing articles
A foreign object inspection device using combined low- and high-directivity light sources with light-shielding plates and a drive unit addresses the accuracy and cost issues in existing technologies, enabling efficient and cost-effective inspection.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- CANON KK
- Filing Date
- 2024-11-26
- Publication Date
- 2026-06-05
AI Technical Summary
The reduction in inspection accuracy of foreign object inspection due to light reflection from the holding portion of the object, which is irradiated during the inspection process, and the high cost and time consumption associated with using highly directional illumination light sources for foreign object inspection.
A foreign object inspection device employing a combination of low- and high-directivity light sources to inspect different regions of the object in parallel, with light-shielding plates to prevent interference, and a drive unit to adjust the relative position of the light sources and object, enabling efficient and accurate inspection.
The device achieves improved inspection accuracy and reduced costs by utilizing low- and high-directivity light sources in combination, allowing for efficient and cost-effective foreign object inspection without flare generation and increased throughput.
Smart Images
Figure 2026092354000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a foreign object inspection apparatus, an exposure apparatus, and a method for manufacturing an article.
Background Art
[0002] In a lithography process, which is one of the manufacturing processes of semiconductor devices and liquid crystal display devices, a process of exposing a circuit pattern formed on a mask to a wafer or a glass substrate coated with a resist through a projection optical system using an exposure apparatus is performed. If foreign matter adheres to an object such as a mask serving as an original plate, the shape of the foreign matter is exposed on the wafer or the glass substrate simultaneously with the circuit pattern, which causes a reduction in yield. Therefore, a foreign object inspection apparatus is mounted on the exposure apparatus, and the presence or absence of foreign objects on the object is inspected using the foreign object inspection apparatus.
[0003] Patent Document 1 discloses content related to a foreign object inspection apparatus that inspects for foreign objects in an inspection region on the inspection surface of a second object (correction plate) separated from a first object (original plate).
Prior Art Documents
Patent Documents
[0004]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0005] However, if the holding portion that holds the second object is also irradiated with light, the inspection accuracy of the foreign object inspection may be reduced due to the light reflected by the holding portion.
[0006] Therefore, an object of the present invention is to provide a foreign object inspection apparatus that is advantageous for performing foreign object inspection.
Means for Solving the Problems
[0007] To achieve the above objective, a foreign object inspection device as one aspect of the present invention is a foreign object inspection device for inspecting foreign objects on an object, comprising: a first light source for inspecting foreign objects in a first region of the object; and a second light source having higher directivity than the first light source and for inspecting foreign objects in a second region of the object that is different from the first region, characterized in that the inspection of foreign objects in the first region and the inspection of foreign objects in the second region are performed in parallel. [Effects of the Invention]
[0008] According to the present invention, it is possible to provide a foreign object inspection device that is advantageous for performing foreign object inspection. [Brief explanation of the drawing]
[0009] [Figure 1] This is a schematic diagram showing the configuration of a foreign object inspection device. [Figure 2] This figure shows the area illuminated with low-directivity lighting. [Figure 3] This figure shows the illumination using highly directional light. [Figure 4] This flowchart shows an example of a foreign object inspection sequence using a foreign object inspection device. [Figure 5] This figure shows an example of the results of a foreign object inspection. [Figure 6] This is a schematic diagram showing the configuration of the exposure apparatus. [Figure 7] This is a schematic diagram showing the configuration of the deflection correction member. [Figure 8] This is a flowchart of the manufacturing method for an item. [Modes for carrying out the invention]
[0010] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In each drawing, the same reference numeral is used for identical components, and redundant descriptions are omitted.
[0011] <Embodiment of a foreign object inspection device> Figure 1 is a schematic diagram of the foreign object inspection device 1 according to this embodiment. The object to be inspected 5 (object) is the object to be inspected by the foreign object inspection device 1, and its periphery is supported (held) by a frame 6 (holding part). The foreign object inspection device 1 in this embodiment includes inspection parts 1a, 1b, and 1c. The foreign object inspection device 1 may also have an image processing unit 7, an output unit 8, and a control unit 9 that controls each part.
[0012] The inspection unit 1a includes an illumination unit 2a (first light source) that emits illumination light to illuminate a first region on the subject 5, and a light receiving unit 3a (first light receiving unit) that receives scattered light from the first region. The inspection unit 1b includes an illumination unit 2b (second light source) that emits illumination light to illuminate a second region on the subject 5, and a light receiving unit 3b (second light receiving unit) that receives scattered light from the second region. The inspection unit 1c includes an illumination unit 2c (third light source) that emits illumination light to illuminate a third region on the subject 5, and a light receiving unit 3c (third light receiving unit) that receives scattered light from the third region. The first to third regions may be mutually exclusive regions, or they may be regions that partially overlap.
[0013] Here, the illumination unit 2a is equipped with an illumination light source that has lower directivity than illumination units 2b and 2c, such as LED light, while illumination units 2b and 2c are equipped with illumination light sources that have higher directivity than illumination unit 2a, such as laser light. Furthermore, the light receiving units 3a, 3b, and 3c are equipped with an image sensor such as a CMOS sensor or a CCD sensor, and a storage medium that can store and accumulate the received light data in chronological order.
[0014] In this embodiment, the test subject 5 is moved in the Y direction (scanning direction) as defined in Figure 1 by the drive unit 10 installed on the frame 6, while performing foreign object inspection in the inspection area. Alternatively, the illumination units 2a to 2c are moved in the -Y direction while performing foreign object inspection in the inspection area. That is, the drive unit 10 changes the relative position of the test subject 5 and the illumination units 2a to 2c. The drive unit 10 may be equipped with, for example, a long-axis linear motor capable of driving horizontally in the Y direction.
[0015] In this case, the inspection unit 1a having relatively low-directivity illumination light is arranged to inspect an inspection area including the surface of the specimen 5 near the frame arranged so as to be orthogonal to the driving direction of the specimen 5. On the other hand, the inspection units 1b and 1c having relatively high-directivity illumination light are arranged to inspect an inspection area including the surface of the specimen 5 near the frame arranged parallel to the driving direction of the specimen 5.
[0016] Then, a light-shielding plate 4a is arranged at the boundary between the first area and the second area in order to avoid interference of the illumination light emitted from the illumination units 2a and 2b, respectively. Further, a light-shielding plate 4b is arranged at the boundary between the first area and the third area in order to avoid interference of the illumination light emitted from the illumination units 2a and 2c, respectively. Note that the light-shielding plate 4a may be arranged so that the light from the illumination unit 2a having high directivity is not projected onto the second area, and the light-shielding plate 4b may be arranged so that the light from the illumination unit 2a having high directivity is not projected onto the third area.
[0017] Next, a method for suppressing flare generation by illumination light in the inspection area near the frame will be described using FIGS. 2 and 3. FIG. 2 simulates a state where an inspection area near the frame arranged parallel to the driving direction of the specimen 5 is illuminated with the relatively low-directivity illumination light 12 provided in the inspection unit 1a, for example. On the other hand, FIG. 3 simulates a state where the same inspection area as in FIG. 2 is illuminated using the inspection unit 1b as illustrated in the present embodiment of FIG. 1.
[0018] In FIG. 2, an inspection area on the specimen 5 is drawn in a mesh pattern. Since the specimen 5 is a transparent flat plate, the illumination light 12 incident in the normal direction with respect to the plane of the specimen 5 passes downward without reflection. Further, although not illustrated in FIG. 2, if there is a foreign object on the inspection area, the illumination light 12 is diffusely reflected by the foreign object, and a part of the scattered light enters the light-receiving unit. The foreign object inspection device 1 discriminates the presence or absence of a foreign object by utilizing the difference in the light intensity between the foreign object and the reflected light around it.
[0019] However, the illumination light 12 with low directivity is difficult to adjust to precisely illuminate only the inspection area due to its characteristics. Therefore, a part of the illumination light 12 is emitted toward the outside of the inspection area and also toward the frame body 6. The illumination light emitted in this way is diffusely reflected by the frame body 6, and a part of the scattered light 13 enters the light receiving part. This is the principle of flare generation that causes false detection of foreign objects.
[0020] In this embodiment, in order to suppress flare generation due to scattered light caused by the frame body, the surface of the object to be inspected near the frame body is inspected using the inspection unit 1b equipped with a highly directional illumination light source. Here, the highly directional illumination light source is, for example, a laser beam, and can be, for example, a laser with a spot diameter of several tens of μm at the focal position and a minimum detection resolution of several μm. By adopting a laser in the inspection unit 1b, it becomes possible to precisely illuminate only the inspection area with an accuracy of 1 mm or less as shown in FIG. 3. And by adjusting the illumination light 14 emitted from the inspection unit 1b to be incident in the normal direction with respect to the plane of the object to be inspected 5, flare generation due to scattered light caused by the frame body can be suppressed.
[0021] However, when adopting a foreign object inspection device equipped with a highly directional illumination light source, there is one problem. That is, if the inspection device is designed to inspect the entire inspection area of the object to be inspected 5 only with a foreign object inspection device equipped with a highly directional illumination light source, the cost will be extremely higher than that of the conventional foreign object inspection device. The inspection accuracy of the foreign object inspection device mounted on the exposure device is not directly related to the main body performance of the exposure device such as overlay and resolution. Therefore, in order to increase the added value of the exposure device, in this embodiment, it is required to make the conventional foreign object inspection device compatible with both inspection accuracy and throughput, and to suppress the cost.
[0022] In this embodiment, inspection units 1b and 1c are equipped with highly directional illumination light to inspect the minimum necessary inspection area near the frame, which is arranged parallel to the driving direction of the specimen 5, and inspection unit 1a is equipped with less directional illumination light to inspect the remaining inspection area. Furthermore, by arranging light-shielding plates 4a and 4b on the boundary of the inspection area, illumination light emitted from inspection unit 1a is prevented from being incident toward the frame 6, enabling simultaneous inspection by inspection units 1a, 1b, and 1c, and optimal dimming of the illumination units in each inspection unit. Note that simultaneous inspection may refer to inspections performed at exactly the same time, or to inspections where a portion of the inspection period overlaps.
[0023] Furthermore, inspection for foreign objects at the boundary of the inspection area where the light-shielding plates 4a and 4b are positioned is performed by the inspection unit 1a equipped with low-directivity illumination light. In this embodiment, the inspection area near the frame, which is positioned perpendicular to the driving direction of the specimen 5, is also inspected using the inspection unit 1a. A known inspection method involves, for example, adding an illumination unit in addition to the illumination unit 2a, which is positioned parallel to the illumination unit 2a and adjusted to illuminate the same inspection area, and performing the inspection while changing the illuminance of the two illumination units.
[0024] Next, the sequence for performing foreign object inspection in this embodiment will be explained using the schematic diagram in Figure 1 and the flowchart in Figure 4.
[0025] First, the control unit 9 moves the object to be inspected 5 in the Y direction to an arbitrary foreign object inspection start position using the drive unit 10 installed on the frame 6 (step 101). At this time, the control unit 9 constantly monitors the position information of the object to be inspected 5 using the position measurement unit 11. Here, the position measurement unit 11 is equipped with, for example, a laser interferometer capable of measuring distance with high precision.
[0026] After the subject 5 has finished moving to the inspection start position, the control unit 9 starts the inspection units 1a, 1b, and 1c via the image processing unit 7 (step 102). Specifically, it starts the emission of illumination light from the illumination units 2a, 2b, and 2c to the inspection area, and starts the light reception and saving of the received light data from the light receiving units 3a, 3b, and 3c.
[0027] Then, the control unit 9 moves the object to be inspected 5 in the Y direction to an arbitrary foreign object inspection end position using the drive unit 10 installed on the frame 6 (step 103). At this time, the control unit 9 constantly monitors the position information of the object to be inspected 5 using the position measurement unit 11. While the object to be inspected 5 is being driven, the light receiving units 3a, 3b, and 3c store and accumulate light reception data. Specifically, table data consisting of pairs of inspection position data of the object to be inspected 5 and light intensity data received by each of the light receiving units at that inspection position is stored and accumulated from the foreign object inspection start position to the inspection end position.
[0028] After the subject 5 has moved to the end of the examination position, the control unit 9 stops the subject 5 using the drive unit 10 installed on the frame 6 (step 104). Then, the control unit 9 stops the examination units 1a, 1b, and 1c via the image processing unit 7 (step 105). Specifically, it stops the emission of illumination light from the illumination units 2a, 2b, and 2c to the examination area, and stops the light reception and saving of the light reception data from the light receiving units 3a, 3b, and 3c.
[0029] Next, the control unit 9 transfers the light reception data acquired by the inspection unit 1a, inspection unit 1b, and inspection unit 1c to the image processing unit 7 and combines it into a single data set as light reception data for the entire inspection area (steps 106 and 107).
[0030] The image processing unit 7 uses the composite data, that is, a table of position data and corresponding light intensity data for the entire inspection area, in addition to a predetermined intensity threshold, to identify foreign objects (step 108). Specifically, it compares each light intensity data that makes up the table data with the threshold, and any data above the threshold is identified as a foreign object.
[0031] Finally, the control unit 9 displays the foreign object detection result from the image processing unit 7 on the output unit 8 (step 109). Figure 5 shows an example of the foreign object detection result, in which the inspection area is divided into a grid at regular intervals so that the location of the foreign object can be easily identified, and the foreign object is displayed in white and everything else in black.
[0032] In this embodiment, the foreign matter inspection by inspection unit 1a is also referred to as the first inspection step, the foreign matter inspection by inspection unit 1b is also referred to as the second inspection step, and the foreign matter inspection by inspection unit 1c is also referred to as the third inspection step. In this embodiment, the first inspection step, the second inspection step, and the third inspection step are performed in parallel.
[0033] In foreign object inspection using only relatively highly directional light sources, as mentioned above, the small size of the irradiated spot area makes it time-consuming to inspect the entire inspection area, resulting in significant costs. In foreign object inspection using only relatively low-directional light sources, as mentioned above, flare can be a problem. In this embodiment, by using light sources with different directional properties in combination, the above problems can be solved, potentially providing advantages in at least one aspect of the performance, quality, productivity, and production cost of the goods when performing foreign object inspection. Furthermore, in this embodiment, by performing foreign object inspection in the first and second regions in parallel, foreign object inspection on objects can be performed efficiently.
[0034] <Embodiment of an exposure apparatus> Figure 6 shows the configuration of the exposure apparatus in this embodiment. The exposure apparatus 100 includes an illumination optical system 108 that illuminates the mask 107 (original plate), which is the surface to be illuminated, with light, and a projection optical system 101 that projects an image of the pattern formed on the mask 107 onto a substrate 105 placed on the surface to be illuminated 104, which is at a position optically conjugate to the mask 107.
[0035] The illumination optical system 8 may include, for example, an imaging optical system (an optical system that images the slit surface illumination light distribution onto the mask surface illumination light distribution) having a projection magnification of 2x. The presence of this imaging optical system improves the ability to expose a larger area at once. The projection optical system 101 is a reflective optical system that reflects light in the order of mirrors 101, 102, 103, 102, and 101, projecting an image of the pattern on the mask 107 onto the substrate 105 placed on the illuminated surface 104. The projection optical system 101 shown in Figure 6 is a reflective optical system, which reduces chromatic aberration of light from the light source 1 compared to a refractive optical system, making it suitable for broadband illumination. The substrate 105 is supported by a movable stage 106. The projection optical system 101 is not limited to a reflective optical system; it may also be a reflective-refracting optical system or a refractive optical system, in which case it becomes necessary to consider correction of chromatic aberration for the wavelength used. Also, although Figure 6 shows a single projection optical system 101, a configuration with multiple projection optical systems 101 is also possible.
[0036] Figure 7 is a detailed view of the components surrounding the mask 107. Above the mask 107, a deflection correction member 109 and a holding part 110 may be positioned. The deflection correction member 109 is positioned on the upper side of the mask 107, and an airtight chamber 111 (sealed space) may be formed between the deflection correction member 109 and the mask 107. The air pressure inside the airtight chamber 111 can be adjusted via a tube 112. This makes it possible to correct the deflection of the mask 107 due to its own weight (self-weight deflection). The deflection correction member 109 may be a transparent flat plate (glass plate) that transmits exposure light.
[0037] If foreign matter is attached to the deflection correction member 109 or the mask 107, there is a risk that the exposure processing of the exposure apparatus 100 may result in poor exposure resolution. Therefore, the exposure apparatus 100 is equipped with the foreign matter inspection device 1 described above to inspect for foreign matter on at least one of the deflection correction member and the original plate. That is, the subject 5 (object) described above corresponds to the deflection correction member 109 or the mask 107. Also, the frame 6 (holding part) described above corresponds to the holding part 110.
[0038] <Embodiment for manufacturing an article> The method for manufacturing articles according to the embodiment of the present invention is suitable for manufacturing articles such as flat panel displays (FPDs), semiconductor devices, sensors, and optical elements. Figure 8 is a flowchart of the method for manufacturing articles according to this embodiment. The method for manufacturing articles according to this embodiment includes a step of forming a latent image pattern on a photosensitive material coated on a substrate by exposure using the above-mentioned exposure apparatus 100 to obtain an exposed substrate (exposure step, step S11). It also includes a step of developing the substrate exposed in this step to obtain a developed substrate (development step, step S12). Furthermore, this manufacturing method includes other well-known steps (oxidation, film formation, vapor deposition, doping, planarization, etching, resist stripping, dicing, bonding, packaging, etc.) (processing step, step S13). The method for manufacturing articles according to this embodiment is advantageous compared to conventional methods in at least one of the performance, quality, productivity, and production cost of the articles.
[0039] Although preferred embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of its gist. The scope to which the present invention is applicable may be, for example, foreign matter inspection devices provided in semiconductor manufacturing equipment (film deposition equipment, sputtering equipment, annealing equipment, inspection equipment, etc.), organic EL deposition equipment, imprint equipment, planarization equipment, and other substrate processing equipment.
[0040] The disclosures herein include at least the following foreign matter inspection apparatus, foreign matter inspection method, exposure apparatus, and method for manufacturing articles.
[0041] (Item 1) A foreign object inspection device for inspecting foreign objects on an object, A first light source for inspecting foreign matter in a first region of the object, A second light source having higher directivity than the first light source and for inspecting foreign matter in a second region of the object that is different from the first region, It has, A foreign object inspection apparatus characterized by performing foreign object inspection of the first region and foreign object inspection of the second region in parallel.
[0042] (Item 2) The object is held by the holding part, The foreign object inspection apparatus according to item 1, characterized in that the second region is a region closer to the holding portion than the first region.
[0043] (Item 3) A first light receiving unit that receives light emitted from the first light source, A second light receiving unit that receives light emitted from the second light source, A foreign object inspection device according to item 1 or 2, further comprising the above.
[0044] (Item 4) The device further includes a drive unit that changes the relative position of the object, the first light source, and the second light source. A foreign object inspection device according to any one of items 1 to 3, characterized in that it inspects foreign objects on an object while changing the relative position.
[0045] (Item 5) The foreign object inspection apparatus according to any one of items 1 to 4, further comprising a light-shielding plate arranged so that the first light source is not projected onto the second area.
[0046] (Item 6) The foreign object inspection apparatus according to item 5, characterized in that the light-shielding plate is positioned on the boundary between the first region and the second region.
[0047] (Item 7) The foreign object inspection apparatus according to any one of items 1 to 6, characterized in that the first light source is an LED.
[0048] (Item 8) The foreign object inspection apparatus according to any one of items 1 to 7, characterized in that the second light source is a laser.
[0049] (Item 9) A method for inspecting foreign objects on an object, A first inspection step involves using a first light source to inspect for foreign matter in a first region of the object, A second inspection step involves using a second light source with higher directivity than the first light source to inspect for foreign matter in a second region of the object that is different from the first region, Includes, A method for inspecting foreign objects, characterized in that the first inspection step and the second inspection step are performed in parallel.
[0050] (Item 10) An exposure apparatus for exposing an image of the pattern of the original plate onto a substrate, An exposure apparatus characterized by having a foreign object inspection device as described in any one of items 1 to 8.
[0051] (Item 11) The exposure apparatus according to item 10, characterized in that the foreign matter inspection device inspects foreign matter on a deflection correction member that corrects the deflection of the original plate.
[0052] (Item 12) The exposure apparatus according to item 10, characterized in that the foreign matter inspection apparatus inspects for foreign matter on the original plate.
[0053] (Item 13) An exposure step of exposing a substrate using an exposure apparatus described in any one of items 10 to 12 to obtain an exposed substrate, The process includes developing the aforementioned photopolymer substrate to obtain a developed substrate, A method for manufacturing an article, characterized by manufacturing an article from the aforementioned developing substrate. [Explanation of symbols]
[0054] 1. Foreign object inspection device 1a Inspection unit (first light source) 1b Inspection unit (second light source) 5. Subject (object)
Claims
1. A foreign object inspection device for inspecting foreign objects on an object, A first light source for inspecting foreign matter in a first region of the object, A second light source having higher directivity than the first light source and for inspecting foreign matter in a second region of the object that is different from the first region, It has, A foreign object inspection apparatus characterized by performing foreign object inspection of the first region and foreign object inspection of the second region in parallel.
2. The object is held by the holding part, The foreign object inspection apparatus according to claim 1, characterized in that the second region is a region closer to the holding portion than the first region.
3. A first light receiving unit that receives light emitted from the first light source, A second light receiving unit that receives light emitted from the second light source, The foreign object inspection device according to claim 1, further comprising the following:
4. The device further includes a drive unit that changes the relative position of the object, the first light source, and the second light source. The foreign object inspection device according to claim 1, characterized in that it inspects foreign objects on an object while changing the relative position.
5. The foreign object inspection apparatus according to claim 1, further comprising a light-shielding plate positioned so that the first light source is not projected onto the second region.
6. The foreign object inspection apparatus according to claim 5, characterized in that the light-shielding plate is arranged on the boundary between the first region and the second region.
7. The foreign object inspection apparatus according to claim 1, characterized in that the first light source is an LED.
8. The foreign object inspection apparatus according to claim 1, characterized in that the second light source is a laser.
9. A method for inspecting foreign objects on an object, A first inspection step involves using a first light source to inspect for foreign matter in a first region of the object, A second inspection step involves using a second light source with higher directivity than the first light source to inspect for foreign matter in a second region of the object that is different from the first region, Includes, A method for inspecting foreign objects, characterized in that the first inspection step and the second inspection step are performed in parallel.
10. An exposure apparatus for exposing an image of the pattern of the original plate onto a substrate, An exposure apparatus characterized by having a foreign object inspection device according to any one of claims 1 to 8.
11. The exposure apparatus according to claim 10, characterized in that the foreign matter inspection device inspects foreign matter on a deflection correction member that corrects the deflection of the original plate.
12. The exposure apparatus according to claim 10, characterized in that the foreign matter inspection device inspects for foreign matter on the original plate.
13. An exposure step of exposing a substrate using the exposure apparatus described in claim 10 to obtain an exposed substrate, The process includes developing the aforementioned photopolymer substrate to obtain a developed substrate, A method for manufacturing an article, characterized by manufacturing an article from the aforementioned developing substrate.