Defect inspection device, substrate bonding apparatus, and defect inspection method

Abstract

To provide a defect inspection device capable of inspecting whether or not a defect exists inside a bonded substrate while eliminating or reducing water droplets generated by dew condensation.SOLUTION: A defect inspection device 2d comprises: a stage 14 that supports or holds a bonded substrate W in a housing 10 that stores the bonded substrate W which is formed of two bonded substrates; a light source 15 that locally heats the bonded substrate W by emitting light toward a target region in a light-receiving surface Wu of the bonded substrate W; an infrared camera 15 that detects a temperature distribution of the target region irradiated with the light from the light source 15; an actuator 17 that changes a position at which the light from the light source 15 is irradiated on the bonded substrate W; and a cooling device 21 that lowers the ambient temperature in the housing 10 while forming a flow of the cooling gas in the housing 10 by supplying cooling gas having the temperature lower than the ambient temperature outside the housing 10 into the housing 10.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to the inspection of bonded substrates, which are an example of objects to be inspected. [Background technology]

[0002] Patent Document 1 discloses a defect inspection device including a stage, a laser light source, and an infrared camera. A sample including a first member and a second member bonded with a bonding material is placed on the stage. The stage includes a cooling unit that cools the first member included in the sample. Patent Document 1 discloses cooling the stage with a refrigerant such as cooling water. Patent Document 1 further discloses sending air from below the sample using a cooling fan or the like, and blowing the air onto the surface of the second member, a semiconductor chip. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018 / 212087 Summary of the Invention [Problem to be solved by the invention]

[0004] Patent Document 1 discloses maintaining the stage at a low temperature and blowing air onto the sample on the stage. However, if only the stage or its vicinity is maintained at a low temperature, condensation may occur on the surface of the stage, and water droplets may adhere to the sample. Adhesion of water to the sample can cause stains such as watermarks and contamination of the sample.

[0005] Therefore, embodiments of the present invention provide a defect inspection device, a substrate bonding device, and a defect inspection method that can inspect whether or not there are defects inside a bonded substrate while eliminating or reducing water droplets caused by condensation. [Means for solving the problem]

[0006] One embodiment of the present invention provides a defect inspection device including: a housing that accommodates a bonded substrate, which is two bonded substrates; a stage that supports or holds the bonded substrate within the housing; a light source that emits light toward a target area within a light-receiving surface of the bonded substrate supported or held by the stage, thereby locally heating the bonded substrate; an infrared camera that detects a temperature distribution in the target area irradiated with the light from the light source by photographing the target area of ​​the bonded substrate supported or held by the stage; at least one actuator that changes the position at which the light from the light source is irradiated on the bonded substrate supported or held by the stage by moving at least one of the light source and the stage and the bonded substrate; and a cooling device that supplies a cooling gas that is lower in temperature than the outside of the housing into the housing, thereby forming a flow of the cooling gas within the housing and lowering the temperature within the housing.

[0007] In the embodiment, at least one of the following features may be added to the defect inspection apparatus.

[0008] The cooling device blows the cooling gas toward an area within the light-receiving surface other than the target area.

[0009] When the irradiation process of irradiating the light from the light source onto the light receiving surface of the bonded substrate supported or held by the stage is performed multiple times, the at least one actuator changes the relative positions of the stage and the bonded substrate with respect to the cooling device so that the cooling gas blown out from the cooling device directly hits the light receiving area, which is the area within the light receiving surface that was irradiated with the light from the light source in the most recent irradiation process, after the infrared camera captures an image of the light receiving area.

[0010] When the irradiation process of irradiating the light from the light source onto the light receiving surface of the bonded substrate supported or held by the stage is performed multiple times, the at least one actuator changes the position at which the light from the light source is irradiated onto the bonded substrate supported or held by the stage so that the target area does not overlap with a light receiving area, which is an area within the light receiving surface that was irradiated with the light from the light source in the most recent irradiation process, and a peripheral area, which is an area within the light receiving surface to which heat from the light receiving area is transferred.

[0011] The cooling device includes a gas exhaust port through which gas enters the housing, a cooler that cools the gas that has entered the gas exhaust port within the housing, and a gas supply port that supplies the gas cooled by the cooler into the housing as the cooling gas.

[0012] Another embodiment of the present invention provides a substrate bonding apparatus comprising a bonding unit that sequentially bonds multiple sets of two substrates, and a defect inspection device that sequentially inspects the multiple sets of two substrates bonded by the bonding unit.

[0013] the defect inspection device includes: a housing that accommodates a bonded substrate, which is two substrates bonded by the bonding unit; a stage that supports or holds the bonded substrate within the housing; a light source that emits light toward a target area within a light-receiving surface of the bonded substrate supported or held by the stage to locally heat the bonded substrate; an infrared camera that detects a temperature distribution in the target area irradiated with the light from the light source by photographing the target area of ​​the bonded substrate supported or held by the stage; at least one actuator that changes the position at which the light from the light source is irradiated on the bonded substrate supported or held by the stage by moving at least one of the light source and the stage and the bonded substrate; and a cooling device that supplies a cooling gas that is lower in temperature than the outside of the housing into the housing, thereby forming a flow of the cooling gas within the housing and lowering the temperature within the housing.

[0014] The defect inspection device completes an inspection, including an irradiation step of irradiating the light from the light source onto the light-receiving surface of the bonded substrate supported or held on the stage, an imaging step of imaging the light-receiving surface irradiated with the light from the light source with the infrared camera, and a cooling step of causing the cooling device to supply the cooling gas into the housing, for at least one of the bonded substrates before the bonding unit begins bonding the final set of two substrates among the multiple sets of two substrates.

[0015] At least one of the features described above for the defect inspection apparatus may be added to the substrate bonding apparatus.

[0016] Yet another embodiment of the present invention includes a preparation step of supporting or holding a bonded substrate, which is two bonded substrates, by a stage in a housing that accommodates the bonded substrate; a first irradiation step of locally heating the bonded substrate by emitting light from a light source toward a target area in a light receiving surface of the bonded substrate supported or held by the stage; a first photographing step of detecting a temperature distribution of the target area irradiated with the light from the light source in the first irradiation step by photographing the target area of ​​the bonded substrate supported or held by the stage with an infrared camera; and a second photographing step of detecting a temperature distribution of the target area irradiated with the light from the light source in the first irradiation step by causing a cooling device to supply a cooling gas that is lower in temperature than the air temperature outside the housing into the housing after at least the infrared camera has photographed the target area. a first position changing step of changing a position where the light from the light source is irradiated onto the bonded substrate supported or held by the stage by moving at least one of the light source and the stage and the bonded substrate using at least one actuator, a second irradiation step of emitting the light from the light source toward the target area to locally heat the bonded substrate after the position where the light from the light source is irradiated onto the bonded substrate supported or held by the stage has been changed, and a second imaging step of detecting a temperature distribution in the target area irradiated with the light from the light source in the second irradiation step by imaging the target area of ​​the bonded substrate supported or held by the stage with the infrared camera. At least one of the above-described features related to the defect inspection apparatus may be added to the defect inspection method. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a schematic diagram showing the interior of a defect inspection device according to an embodiment of the present invention as viewed horizontally. [Figure 2] FIG. 2 is a schematic diagram showing the inside of the defect inspection device as viewed from above. [Figure 3] 1 is a schematic view showing a part of a cross section of a bonded substrate cut along a plane perpendicular to the bonded substrate; [Figure 4]1 is a schematic diagram showing an area heated by a light source and an area imaged by an infrared camera. [Figure 5] FIG. 10 is a schematic view of the bonded substrate viewed from above during the first irradiation step. [Figure 6] FIG. 10 is a schematic view of the bonded substrate viewed from above during the second irradiation step. [Figure 7] 1 is a flowchart illustrating a defect inspection method according to an embodiment of the present invention. [Figure 8] 1 is a schematic diagram showing a substrate bonding apparatus equipped with a defect inspection device as viewed from above. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0019] Fig. 1 is a horizontal schematic diagram of the interior of a defect inspection apparatus 2d according to one embodiment of the present invention. Fig. 2 is a top schematic diagram of the interior of the defect inspection apparatus 2d. In Fig. 1, three arrows extending downward from the gas supply port 26 represent the cooling gas blown out from the gas supply port 26. This also applies to Figs. 5 and 6, which will be described later.

[0020] The defect inspection device 2d is a device that non-destructively inspects an object for defects without wetting the object. Figures 1 and 2 show an example in which the object is a bonded substrate W. The defect inspection device 2d may detect the position, size, shape, and number of defects in addition to the presence or absence of defects.

[0021] The defect inspection apparatus 2d includes a housing 10 that houses the bonded substrate W, and a stage 14 that supports or holds the bonded substrate W within the housing 10. The defect inspection apparatus 2d further includes a light source 15 that irradiates light onto the bonded substrate W that is supported or held on the stage 14, an infrared camera 16 that photographs the bonded substrate W that is supported or held on the stage 14, and at least one actuator 17 that changes the position at which the light from the light source 15 irradiates the bonded substrate W.

[0022] The housing 10 includes a partition wall 11 that defines an internal space 10s for accommodating a bonded substrate W and a passage opening 12 through which the bonded substrate W passes to enter and exit the internal space 10s, and a door 13 that opens and closes the passage opening 12. The partition wall 11 includes a plate-shaped upper wall 11u disposed above the internal space 10s, a plate-shaped lower wall 11L disposed below the internal space 10s, and a cylindrical peripheral wall 11p that surrounds the internal space 10s. The passage opening 12 may be formed in any one of the upper wall 11u, the lower wall 11L, and the peripheral wall 11p, or may be formed in two or more of these. FIG. 1 shows an example in which the passage opening 12 is formed in the peripheral wall 11p.

[0023] The door 13 is closed except when the bonded substrate W is being inserted into or removed from the housing 10 through the passage opening 12. When the door 13 closes the passage opening 12 in the partition wall 11, the inside of the housing 10 is sealed. The internal space 10s of the housing 10 is a sealed space that does not allow fluid to freely enter or exit. The inside of the housing 10 does not need to be completely sealed as long as the temperature inside the housing 10 can be controlled uniformly.

[0024] The stage 14 is disposed within the housing 10. The stage 14 may support or hold the bonded substrate W horizontally from above or below the bonded substrate W, or may support or hold the bonded substrate W at an angle so that the bonded substrate W faces up or down. FIG. 1 shows an example in which the stage 14 supports the bonded substrate W horizontally from below the bonded substrate W.

[0025] 1, the upper surface 14u of the stage 14 is parallel to the lower surface of the bonded substrate W and faces the lower surface of the bonded substrate W in the vertical direction. When the bonded substrate W on the stage 14 is viewed in a direction perpendicular to the upper surface of the bonded substrate W, the upper surface 14u of the stage 14 may be larger or smaller than the upper surface of the bonded substrate W, or may be the same size as the upper surface of the bonded substrate W. The stage 14 may support the bonded substrate W with the upper surface 14u of the stage 14 in contact with the lower surface of the bonded substrate W, or may support the bonded substrate W with the upper surface 14u of the stage 14 separated from the entire lower surface of the bonded substrate W.

[0026] The stage 14 may be supported by the housing 10 via a vibration isolation table 18, or may be supported by the housing 10 without the vibration isolation table 18. FIG. 1 shows an example of the former. In this example, the vibration isolation table 18 of the defect inspection apparatus 2d is disposed between the floor of the housing 10 and the underside of the stage 14, and the stage 14 is supported by the vibration isolation table 18. The vibration isolation table 18 reduces vibration of the stage 14 relative to the housing 10. The vibration isolation table 18 may include a table 18a that supports the stage 14 between the floor of the housing 10 and the underside of the stage 14, a vibration sensor 18b that detects vibration of the table 18a relative to the housing 10, and a vibration isolation actuator 18c that reduces vibration of the table 18a by moving the table 18a based on the detection value of the vibration sensor 18b.

[0027] Light source 15 is disposed in the space within housing 10 above stage 14. Light source 15 may be fixed to housing 10 or may be movable relative to housing 10. In the example shown in FIG. 1 , the upper surface of bonded substrate W is a light-receiving surface Wu that is irradiated with light from light source 15, and the lower surface of bonded substrate W is a non-light-receiving surface WL opposite the light-receiving surface Wu. Light source 15 may be a laser light source that emits laser light toward bonded substrate W on stage 14, or may be a lamp such as a xenon lamp used as a flash lamp, or may be something other than these.

[0028] The infrared camera 16 is disposed in a space within the housing 10 above the stage 14. The infrared camera 16 may be fixed to the housing 10 or may be movable relative to the housing 10. The infrared camera 16 is a camera that generates an image showing the temperature distribution of an object by detecting the temperature of the object using an infrared sensor. The infrared camera 16 is also called a thermal camera or a thermograph. The infrared camera 16 photographs the bonded substrate W at least either while the bonded substrate W is being irradiated with light from the light source 15 or after the bonded substrate W is irradiated with light from the light source 15. The infrared camera 16 may photograph the same region in the bonded substrate W multiple times to detect changes in the temperature distribution of this region over time.

[0029] The actuator 17 moves at least one of the light source 15 and the stage 14 and the bonded substrate W, thereby changing the position at which the light from the light source 15 is irradiated onto the bonded substrate W supported or held by the stage 14. FIG. 1 shows an example in which the light source 15 and the infrared camera 16 are fixed to the housing 10, and the actuator 17 moves the stage 14 relative to the housing 10.

[0030] 1, the actuator 17 includes at least one horizontal actuator that moves the stage 14 horizontally relative to the housing 10. The at least one horizontal actuator includes an X-direction actuator 17x that translates the stage 14 in the horizontal X direction relative to the housing 10, and a Y-direction actuator 17y that translates the stage 14 in the horizontal Y direction perpendicular to the X direction relative to the housing 10.

[0031] When the actuator 17 includes an X-direction actuator 17x and a Y-direction actuator 17y, the stage 14 includes an X-direction stage 14x that is movable in parallel in the X direction relative to the housing 10, and a Y-direction stage 14y that is movable in parallel in the Y direction relative to the housing 10. Fig. 1 shows an example in which the X-direction stage 14x is supported by the Y-direction stage 14y. When the Y-direction actuator 17y moves the Y-direction stage 14y in parallel in the Y direction relative to the housing 10, the X-direction stage 14x moves in parallel in the Y direction relative to the housing 10 together with the Y-direction stage 14y.

[0032] The defect inspection apparatus 2d further includes a cooling device 21 that supplies cooling gas into the housing 10 at a temperature lower than the temperature outside the housing 10, thereby forming a flow of cooling gas inside the housing 10 and lowering the temperature inside the housing 10. The cooling gas may be air such as clean air or dry air, or an inert gas such as nitrogen gas, or other gases.

[0033] The temperature of the cooling gas is lower than the temperature (e.g., 20 to 30°C) of the outer surface of the housing 10 (the outer surface of the partition wall 11 and the door 13). The temperature of the cooling gas may be higher or lower than the freezing point of water, or may be equal to the freezing point of water. After a certain amount of time has passed since the supply of the cooling gas began, the air temperature inside the housing 10 is maintained at a temperature equal to or approximately equal to the temperature of the cooling gas.

[0034] The temperature of the cooling gas supplied into housing 10 may be constant or may vary throughout the entire period that the cooling gas is supplied into housing 10. By supplying cooling gas into housing 10, cooling device 21 may stabilize the air temperature inside housing 10 at a target temperature that is lower than the air temperature outside housing 10 while forming a flow of cooling gas inside housing 10. In this case, cooling device 21 may change at least one of the temperature and flow rate of the cooling gas in response to changes in the air temperature inside housing 10.

[0035] Cooling device 21 may be of a circulation type that cools gas inside housing 10 while circulating it, or may be of an outside air introduction type that supplies cooled gas outside housing 10 as cooling gas into housing 10 while exhausting gas inside housing 10, or may be of some other type. When cooling device 21 is of a circulation type, the path through which the circulating gas passes may pass outside housing 10, or may be located only inside housing 10.

[0036] When at least one of exhausting the gas inside the housing 10 to the outside of the housing 10 and supplying the gas outside the housing 10 into the housing 10 is performed, the control device 30, which will be described later, may control the air pressure inside the housing 10 by controlling the cooling device 21. For example, the control device 30 may control the flow rate of the cooling gas supplied into the housing 10 and the flow rate of the gas exhausted from the housing 10 by controlling the cooling device 21 so that the air pressure inside the housing 10 is maintained higher or lower than the air pressure outside the housing 10, or is equal to the air pressure outside the housing 10.

[0037] 1, the cooling device 21 includes a gas supply port 26 that supplies cooling gas into the housing 10, a gas exhaust port 22 through which the gas inside the housing 10 enters, and a cooler 23 that cools the gas to be supplied from the gas supply port 26 into the housing 10. The cooling device 21 further includes a fan 24 that sends the cooling gas toward the gas supply port 26, or a pump that sucks the cooling gas into the housing 10 from the gas supply port 26 by sucking the gas inside the housing 10 into the gas exhaust port 22.

[0038] The gas supply port 26 and the gas exhaust port 22 may be provided in the same member, such as the housing 25, or may be provided in separate members. The cooler 23 may be at least one of a heat exchanger and a Peltier element, or may be something other than these. The cooler 23 may be located either inside or outside the housing 10. The cooling device 21 may include a cooler 23 located inside the housing 10 and a cooler 23 located outside the housing 10. The cooling device 21 may include both a fan 24 and a pump.

[0039] FIG. 1 shows an example of an internal circulation type cooling device 21 that circulates gas within the housing 10 only within the housing 10. In this example, the cooling device 21 includes a housing 25 provided with a gas supply port 26 and a gas exhaust port 22, an evaporator that cools the gas within the housing 25, and a fan 24 that sends the gas within the housing 25 cooled by the evaporator toward the gas supply port 26. The evaporator is an example of a cooler 23 and a heat exchanger. The evaporator and fan 24 are disposed within the housing 25. The housing 25 is disposed in a space within the housing 10, above the stage 14. The gas within the housing 10 enters the housing 25 through the gas exhaust port 22 and is cooled within the housing 25 by the evaporator. The gas cooled by the evaporator is blown out of the housing 25 through the gas supply port 26.

[0040] FIG. 1 shows an example in which the gas supply port 26 blows cooling gas downward toward the light-receiving surface Wu of the bonded substrate W on the stage 14. As shown in FIG. 2, in this example, when the stage 14 and the cooling device 21 are viewed from above, the gas supply port 26 overlaps with the bonded substrate W on the stage 14. At least a portion of the cooling gas blown out from the gas supply port 26 directly hits the light-receiving surface Wu of the bonded substrate W on the stage 14. The cooling gas may directly hit the entire light-receiving surface Wu, or may directly hit only a portion of the light-receiving surface Wu. In the latter case, the cooling gas may directly hit only a portion of the light-receiving surface Wu excluding a target region R2 (see FIG. 4), which will be described later.

[0041] The gas supply port 26 may discharge the cooling gas horizontally, obliquely upward, or obliquely downward so that the cooling gas does not directly impinge on the bonded substrate W. The gas supply port 26 may change the direction in which the cooling gas is discharged while discharging the cooling gas. In this case, the cooling gas may directly impinge on the bonded substrate W for all or part of the period in which the gas supply port 26 is discharging the cooling gas.

[0042] Cooling device 21 may supply cooling gas into housing 10 from gas supply port 26 while bonded substrate W is inside housing 10, and at least either before or after bonded substrate W is placed inside housing 10. When the supply of cooling gas continues, the cooling gas reaches every corner of internal space 10s of housing 10. This maintains not only the air temperature inside housing 10 but also the temperatures of objects placed inside housing 10, such as stage 14, at a temperature equal to or approximately equal to the temperature of the cooling gas.

[0043] The defect inspection apparatus 2d includes a control device 30 that controls the electrical and electronic devices included in the defect inspection apparatus 2d. The control device 30 includes a CPU (central processing unit) 30a that processes information, such as executing programs, and a memory 30b that stores information, such as programs, to be executed by the CPU 30a. The control device 30 further includes a communication module 30c that performs at least one of the following functions: transmitting information transmitted from the CPU 30a or memory 30b to a device other than the control device 30, and receiving information transmitted from a device other than the control device 30 and transmitting the information to the CPU 30a or memory 30b. The control device 30 controls the defect inspection apparatus 2d to inspect a bonded substrate W, which is an example of an object. In other words, the control device 30 is programmed to perform the inspection of the bonded substrate W, as described below.

[0044] The inspection of the bonded substrate W includes a defect determination for determining whether or not there is a defect in the bonded substrate W based on an image generated by the infrared camera 16. The control device 30 may store a defect determination application program 30d for performing the defect determination. In addition to or instead of the defect determination being performed by the control device 30, the defect determination may be performed by a device other than the control device 30. In this case, the control device 30 may store the image generated by the infrared camera 16 in the memory 30b.

[0045] Next, a bonded substrate W, which is an example of an object to be inspected, will be described.

[0046] Fig. 3 is a schematic diagram showing a part of a cross section of bonded substrate W cut along a plane perpendicular to bonded substrate W. Fig. 4 is a schematic diagram showing an area heated by light source 15 and an area photographed by infrared camera 16. Figs. 5 and 6 are schematic diagrams of bonded substrate W viewed from above during the first and second irradiation steps. Fig. 7 is a flowchart for explaining a defect inspection method according to one embodiment of the present invention.

[0047] The upper side of Fig. 4 shows a view of the light receiving surface Wu of the bonded substrate W as seen from above. The lower side of Fig. 4 shows a cross section of the bonded substrate W taken along line IV-IV shown in the upper side of Fig. 4. In the upper side of Fig. 4, for convenience, the infrared camera 16 is arranged above the area heated by the light source 15. In Figs. 5 and 6, for convenience, the infrared camera 16 and the cooling device 21 are arranged above the bonded substrate W. The proportions, sizes, etc. shown in Figs. 3 to 6 may not be the same as the actual proportions, etc. For example, in Figs. 5 and 6, the size of the target area R2 relative to the bonded substrate W may not be the same as the actual size.

[0048] 3, the bonded substrate W is two bonded substrates Wx. The substrate Wx may be any one of a semiconductor wafer, a substrate for an FPD (Flat Panel Display) such as a liquid crystal display device or an organic EL (electroluminescence) display device, a substrate for an optical disk, a substrate for a magnetic disk, a substrate for a magneto-optical disk, a substrate for a photomask, a ceramic substrate, and a substrate for a solar cell, or may be other than these.

[0049] The two bonded substrates Wx are, for example, two circular substrates of equal diameters bonded in parallel so that their centers coincide. The two bonded substrates Wx may differ from each other in at least one of their shapes and sizes. The substrate Wx may be a patterned substrate on which a structure such as a pattern or a semiconductor device is formed, or an unpatterned substrate on which no structure is formed. When one of the two substrates Wx is a patterned substrate, the other of the two substrates Wx may be either a patterned substrate or an unpatterned substrate. The material of the substrate Wx (when a structure is formed on the surface of a substrate, the material of the substrate; the same applies below) may be a semiconductor or a material other than a semiconductor. The material of one substrate Wx may be the same as or different from the material of the other substrate Wx.

[0050] The two substrates Wx are bonded together with their bonding surfaces in contact with each other. The bonding surface of the two bonded substrates Wx corresponds to the interface between the two bonded substrates Wx. A portion at the interface that has a defect such as a void 40 (cavity) is defined as a defective portion 41, and a portion at the interface that does not have any defects such as the void 40 is defined as a healthy portion 42. The defective portion 41 is a portion that overlaps with the void 40 when viewed in a direction perpendicular to the light-receiving surface Wu of the bonded substrate W.

[0051] Even if the same amount of heat per unit volume is applied to the defective portion 41 and the healthy portion 42, the defective portion 41 exhibits a different temperature change from the healthy portion 42. When both the defective portion 41 and the healthy portion 42 are heated, the difference in how the defective portion 41 and the healthy portion 42 heat up is reflected in the temperature distribution of the light-receiving surface Wu of the bonded substrate W. Therefore, by detecting the temperature distribution of the light-receiving surface Wu of the heated bonded substrate W, it is possible to inspect for the presence of defects such as voids 40.

[0052] 4, the light source 15 emits light toward a target region R2, which is an area within the light-receiving surface Wu of the bonded substrate W on the stage 14. The target region R2 is an area onto which the light source 15 intends to irradiate the bonded substrate W with light, and the light-receiving region R3 is an area within the bonded substrate W onto which the light from the light source 15 is actually irradiated. The target region R2 onto which the light from the light source 15 is irradiated is the light-receiving region R3, which coincides with the target region R2.

[0053] Even if the stage 14 moves relative to the housing 10, the position of the target region R2 relative to the housing 10 does not change as long as the position of the light source 15 relative to the housing 10 does not change. When the stage 14 and bonded substrate W are moved relative to the light source 15, the stage 14 and bonded substrate W move relative to the target region R2. When the stage 14 and bonded substrate W are considered as references, the target region R2 moves within the light-receiving surface Wu. When the stage 14 and bonded substrate W are moved relative to the light source 15 after irradiating the bonded substrate W with light from the light source 15, the light-receiving region R3 moves relative to the target region R2.

[0054] 4, the light source 15 irradiates light only onto the target region R2, thereby heating only the heated portion, which is a part of the bonded substrate W that includes the target region R2. The heated portion is composed of the target region R2 irradiated with light, a peripheral region R4 that is an area within the light-receiving surface Wu that is in contact with the target region R2, and an internal region that extends from the target region R2 and the peripheral region R4 toward the non-light-receiving surface WL of the bonded substrate W. In FIG. 4, the area between the two dashed double-dashed lines L corresponds to the internal region.

[0055] The target region R2 irradiated with light from the light source 15 is a light-receiving region R3 that coincides with the target region R2. The peripheral region R4 is a region within the light-receiving surface Wu and is adjacent to the target region R2. The outer edge of the peripheral region R4 is the outer edge of a region where a temperature increase occurs when the target region R2 is irradiated with light from the light source 15. The outer edge of the peripheral region R4 may be the outer edge of a region where a temperature change of 3°C or more is confirmed by imaging with the infrared camera 16 before and after the target region R2 is irradiated with light from the light source 15. The peripheral region R4 is a region that is indirectly heated by the light source 15. When the infrared camera 16 images the bonded substrate W, the area of ​​the peripheral region R4 may be smaller or larger than the area of ​​the target region R2.

[0056] The lower the temperature of the bonded substrate W before heating and the greater the temperature difference between the bonded substrate W before and after heating, the more likely it is that defect detection accuracy will improve. When sequentially heating and photographing multiple different regions on the light-receiving surface Wu of the bonded substrate W, if too much heat is applied to a certain region from light source 15, the heat transferred from that region to the unphotographed region increases, causing the temperature of the unphotographed region to rise. Even if too much heat is applied to a certain region from light source 15, as long as the temperature of the cooling gas is low, the temperature of the unphotographed region will drop to a value that does not affect defect detection accuracy before light irradiation of the unphotographed region begins. The energy of the light emitted by light source 15 and the temperature of the cooling gas can be determined taking these factors into consideration. When the bonded substrate W is a circular substrate with a diameter of 300 mm and the temperature of the cooling gas is above 0 but below room temperature (e.g., 20 to 30°C), the temperature difference in the target region R2 before and after irradiation with light from light source 15 may be, for example, within a range of 1 to 10°C, or outside this range.

[0057] The infrared camera 16 captures an image of a photographic region R1, which is an area within the light-receiving surface Wu of the bonded substrate W on the stage 14. The photographic region R1 includes at least a portion of the target region R2. The photographic region R1 may include part or all of the target region R2 and the area within the light-receiving surface Wu other than the target region R2, or it may include only the target region R2. In the former case, the photographic region R1 may include the entire light-receiving surface Wu. In the latter case, the photographic region R1 may coincide with the target region R2 or may be smaller than the target region R2. Figure 4 shows an example in which the photographic region R1 is smaller than the target region R2 and the outer edge of the photographic region R1 is surrounded by the outer edge of the target region R2. The photographic region R1 may be rectangular as shown in Figure 4, or may have a shape other than a rectangle. The same applies to the target region R2, the light-receiving region R3, and the peripheral region R4.

[0058] The infrared camera 16 captures an image of the image capture area R1, generating an image showing the temperature distribution in the image capture area R1. If a defect such as a void 40 exists in a position overlapping the image capture area R1 when viewed perpendicularly to the light-receiving surface Wu of the bonded substrate W, when the image capture area R1 is heated, the position in the image capture area R1 overlapping the defect will exhibit a different temperature change than the other positions in the image capture area R1. Therefore, it is possible to determine whether or not there is a defect in the image capture area R1 based on the image generated by the infrared camera 16. Furthermore, if there is a defect, the position, size, shape, and number of the defect can be identified or measured based on the image.

[0059] 4 shows an example in which light source 15 irradiates only target area R2 with light, and infrared camera 16 captures an image of image capture area R1, which is a part of target area R2. In this example, target area R2 and image capture area R1 are smaller than light-receiving surface Wu of bonded substrate W. If the range to be heated and captured is larger than image capture area R1, control device 30 changes the relative positions of stage 14 and bonded substrate W with respect to light source 15 and infrared camera 16 after infrared camera 16 captures an image of bonded substrate W, and then irradiates bonded substrate W with light and captures an image of bonded substrate W again.

[0060] Next, the inspection of the bonded substrate W will be described with reference to FIGS.

[0061] 7, when inspecting bonded substrate W using defect inspection apparatus 2d, control device 30 performs an irradiation step of irradiating bonded substrate W with light from light source 15 (step S1 in FIG. 7) and an imaging step of using infrared camera 16 to capture an image of bonded substrate W irradiated with light from light source 15 (step S2 in FIG. 7). Thereafter, control device 30 checks whether the entire area to be heated and imaged has been heated and imaged (step S3 in FIG. 7). The area to be heated and imaged may be the entire light-receiving surface Wu of bonded substrate W, or may be a part of the light-receiving surface Wu of bonded substrate W.

[0062] If the entire range to be heated and photographed has not been heated and photographed (No in step S3 in FIG. 7), the control device 30 performs a position change step (step S4 in FIG. 7) to change the relative positions of the stage 14 and bonded substrate W with respect to the light source 15 and infrared camera 16. Thereafter, the control device 30 performs the irradiation step (step S1 in FIG. 7) and the photographing step (step S2 in FIG. 7) again. In other words, after performing the first irradiation step and photographing step, the control device 30 executes one or more cycles including the position change step, irradiation step, and photographing step until the entire range to be heated and photographed has been heated.

[0063] 5 shows a state in which the first irradiation step is being performed, and FIG. 6 shows a state in which the second irradiation step is being performed. The conditions for the second and subsequent irradiation steps may be the same as or different from the conditions for the first irradiation step. The same applies to the conditions for the second and subsequent imaging steps. After performing the final imaging step, the control device 30 may perform a position change step to return the stage 14 and bonded substrate W to their initial positions, i.e., the positions of the stage 14 and bonded substrate W before the first irradiation step was performed.

[0064] When performing the second or subsequent irradiation step and photographing step, after the first photographing step has been performed, the actuator 17 moves one or both of the light source 15 and the stage 14 to change the position at which the light from the light source 15 is irradiated onto the bonded substrate W. In the second or subsequent irradiation step, the light source 15 may start emitting the next light simultaneously or almost simultaneously with one of the light source 15 and the stage 14 coming to rest relative to the other, or may start emitting the next light after the other of the light source 15 and the stage 14 comes to rest relative to the other.

[0065] The period from the start of the first irradiation step to the end of the final imaging step is defined as the inspection period. During at least a part of this inspection period, the control device 30 performs a cooling step in which the cooling device 21 supplies cooling gas into the housing 10. Figures 5 and 6 show a state in which the cooling device 21 blows cooling gas toward the bonded substrate W while the bonded substrate W is being irradiated with light from the light source 15.

[0066] The control device 30 may perform a cooling step at least partly during the inspection period, as well as before and / or after the inspection period. When the cooling step is performed before the inspection period, when the bonded substrate W is carried into the housing 10, gas warmer than the gas inside the housing 10 enters the housing 10 through the passage 12 of the housing 10, causing a temporary rise in the temperature inside the housing 10. In such a case, the control device 30 may start the irradiation step after the measurement value of a thermometer measuring the temperature inside the housing 10 has stabilized at the target temperature.

[0067] When the irradiation step is performed multiple times, as shown in Fig. 6, the control device 30 may control the actuator 17 to change the position where the light from the light source 15 is irradiated onto the bonded substrate W so that the target region R2 does not overlap with the light-receiving region R3 and peripheral region R4 generated in the most recent irradiation step (the light-receiving region R3 and peripheral region R4 on the left side in Fig. 6). Region R5 shown in Fig. 6 is the light-receiving region R3 and peripheral region R4 generated in the most recent irradiation step.

[0068] The region within the light-receiving surface Wu to which heat from the target region R2 is transferred when light from the light source 15 is irradiated onto the target region R2 is defined as the latest peripheral region R4. The latest peripheral region R4 is one of the peripheral regions R4. Peripheral regions R4 other than the latest peripheral region R4 are non-latest peripheral regions R4. The control device 30 may control the actuator 17 to change the position at which the light from the light source 15 is irradiated onto the bonded substrate W so that both the target region R2 and the latest peripheral region R4 do not overlap with the light-receiving region R3 and peripheral region R4 generated in the most recent irradiation step, or may change the position at which the light from the light source 15 is irradiated onto the bonded substrate W so that the target region R2 does not overlap with the light-receiving region R3 and peripheral region R4 generated in the most recent irradiation step, and the latest peripheral region R4 overlaps with the peripheral region R4 generated in the most recent irradiation step. Figure 6 shows an example of the former.

[0069] The area of ​​the peripheral region R4 varies depending on several factors, including the amount of heat given to the bonded substrate W from the light source 15, the air temperature inside the housing 10, the temperature of the bonded substrate W, the thermal conductivity of the bonded substrate W, and the time elapsed since the light from the light source 15 was irradiated onto the bonded substrate W.

[0070] The control device 30 may store multiple measurement values ​​of the area of ​​the peripheral region R4 corresponding to multiple conditions in which at least one of the multiple factors is different. Alternatively or additionally, the control device 30 may measure the change in the area of ​​the peripheral region R4 after the irradiation step using a thermometer such as the infrared camera 16, and store the relationship between the area of ​​the peripheral region R4 and the time elapsed since the bonded substrate W was irradiated with light from the light source 15. The control device 30 may move the target region R2, etc., away from the light-receiving region R3 and the peripheral region R4 generated in the most recent irradiation step, based on at least one of the measurement values ​​and the relationship stored in the control device 30.

[0071] Next, the substrate bonding apparatus 1 equipped with the defect inspection device 2d will be described.

[0072] 8 is a schematic diagram showing a top view of a substrate bonding apparatus 1 equipped with a defect inspection apparatus 2d. The substrate bonding apparatus 1 includes a load port LP that holds carriers CA that accommodate substrates Wx such as FOUPs (Front-Opening Unified Pods), a plurality of processing units 2 that process the substrates Wx transported from the carriers CA on the load port LP, a transport system TS that transports the substrates Wx before and after being processed in the plurality of processing units 2, and a control device 3 that controls the substrate bonding apparatus 1.

[0073] The transfer system TS unloads the substrate Wx from a carrier CA on the load port LP and loads it into a processing unit 2. The transfer system TS further unloads the substrate Wx from the processing unit 2 and loads it into a carrier CA on the load port LP. The carrier CA into which the substrate Wx is loaded may be the same as or different from the carrier CA from which the substrate Wx was unloaded. The transfer system TS may transport the substrate Wx from one processing unit 2 to another processing unit 2. The transfer system TS may include at least one transport robot TR that transports one or more substrates Wx in a horizontal position.

[0074] The processing unit 2 may be a single-wafer processing unit 2 that processes each substrate Wx one by one, or a batch processing unit 2 that processes multiple substrates Wx at once. FIG. 8 shows an example in which multiple processing units 2 include an activation unit 2a, a cleaning unit 2b, a bonding unit 2c, and a defect inspection device 2d. The defect inspection device 2d is the defect inspection device 2d shown in FIG. 1. The defect inspection device 2d can also be called an inspection unit. The activation unit 2a, the cleaning unit 2b, the bonding unit 2c, and the defect inspection device 2d are all single-wafer processing units 2.

[0075] The activation unit 2a is a unit that activates the bonding surfaces of the substrates Wx by irradiating the bonding surfaces of the substrates Wx with plasma. The cleaning unit 2b is a unit that cleans the bonding surfaces of the substrates Wx by supplying a cleaning liquid such as pure water (deionized water: DIW) to the bonding surfaces of the substrates Wx unloaded from the activation unit 2a. The bonding unit 2c is a unit that bonds the two substrates Wx unloaded from the cleaning unit 2b by bringing their bonding surfaces into contact with each other. Unless otherwise specified, the bonding unit 2c described in this specification bonds the substrates Wx under atmospheric pressure.

[0076] The control device 3 controls the electrical and electronic devices provided in the substrate bonding apparatus 1. The control device 3 includes a CPU 3a that processes information, such as executing programs, and a memory 3b that stores information, such as programs, to be executed by the CPU 3a. The control device 3 further includes a communication module 3c that performs at least one of transmitting information transmitted from the CPU 3a or memory 3b to devices other than the control device 3 and receiving information transmitted from devices other than the control device 3 and transmitting the information to the CPU 3a or memory 3b. The control device 3 controls the substrate bonding apparatus 1 to transport and process the substrate Wx, as described below. In other words, the control device 3 is programmed to transport and process the substrate Wx, as described below.

[0077] Hereinafter, the two substrates Wx to be bonded will be referred to as the first substrate Wx and the second substrate Wx. When bonding the first substrate Wx and the second substrate Wx and inspecting the bonded substrate W, the transfer system TS transfers the first substrate Wx from the carrier CA on the load port LP to the activation unit 2a, where the activation unit 2a activates the surface of the first substrate Wx. The transfer system TS then transfers the first substrate Wx from the activation unit 2a to the cleaning unit 2b, where the cleaning unit 2b cleans and dries the surface of the first substrate Wx. The transfer system TS then transfers the first substrate Wx from the cleaning unit 2b to the bonding unit 2c.

[0078] The second substrate Wx in the carrier CA on the load port LP is transported to the activation unit 2a and cleaning unit 2b, similar to the first substrate Wx, and is processed there. The second substrate Wx is then transported by the transport system TS to the bonding unit 2c. The bonding unit 2c bonds the first substrate Wx and the second substrate Wx by bringing the bonding surfaces of the cleaned first substrate Wx and second substrate Wx into contact with each other. The transport system TS then transports the bonded substrate W, which is the bonded first substrate Wx and second substrate Wx, to the defect inspection device 2d, which inspects the bonded substrate W. The inspection of the bonded substrate W by the defect inspection device 2d is as described above.

[0079] The substrate bonding apparatus 1 performs the aforementioned processes from the activation process to the inspection process until there are no more substrates Wx to be bonded from the carrier CA on the load port LP. The substrate bonding apparatus 1 then starts processing the second set of first and second substrates Wx before completing inspection of the first bonded substrate W (the first set of first and second substrates Wx). The same applies to the third and subsequent sets of first and second substrates Wx. Therefore, the activation unit 2a processes the subsequent substrates Wx even while other processing units 2, such as the cleaning unit 2b, are processing the substrates Wx. The same applies to the cleaning unit 2b, the bonding unit 2c, and the defect inspection apparatus 2d.

[0080] Before the bonding unit 2c starts bonding the final pair of first and second substrates Wx, the defect inspection device 2d may find a defect in the bonded substrate W. In such a case, the control device 3 may cause at least one of the activation unit 2a, the cleaning unit 2b, and the bonding unit 2c to stop processing the substrate Wx, or may change the conditions for processing the substrate Wx in at least one of the activation unit 2a, the cleaning unit 2b, and the bonding unit 2c so that the subsequent bonded substrate W will have no or fewer defects. In the former case, the control device 3 may be provided with an alarm device that notifies the user that processing of the substrate Wx has been stopped using one or more of light, sound, text, and graphics.

[0081] Next, the effects of this embodiment will be described.

[0082] In this embodiment, light is irradiated onto a target region R2 within the light-receiving surface Wu of the bonded substrate W, which is supported or held by the stage 14. As a result, only a portion of the bonded substrate W, including the target region R2, is heated. The infrared camera 16 detects the temperature distribution in the target region R2 irradiated with light. The bonded substrate W is made up of two bonded substrates Wx. If there is a defect, such as a void 40, at the interface between the two bonded substrates Wx, when the bonded substrate W is heated, the defective portion 41 will exhibit a different temperature change than the non-defective portion 42. Therefore, it is possible to determine whether or not there is a defect inside the bonded substrate W based on the temperature distribution of the heated bonded substrate W.

[0083] Actuator 17 moves light source 15 and / or moves stage 14 and bonded substrate W, thereby changing the position at which light from light source 15 is irradiated onto bonded substrate W. Thereafter, light from light source 15 is irradiated onto bonded substrate W, and infrared camera 16 takes an image of bonded substrate W, allowing an area different from the area previously inspected to be inspected. Therefore, even if the area to be inspected is larger than the area that can be inspected in one inspection, the entire area to be inspected can be inspected.

[0084] The cooling device 21 supplies cooling gas that is lower in temperature than the air temperature outside the housing 10 into the housing 10, thereby forming a flow of cooling gas inside the housing 10 and lowering the air temperature inside the housing 10. This cools objects placed inside the housing 10, such as the stage 14. Because the entire interior of the housing 10 is cooled by the cooling gas, condensation is less likely to occur inside the housing 10. This makes it possible to eliminate or reduce water droplets that are formed due to condensation. Even if condensation does occur, the cooling gas flowing inside the housing 10 promotes the evaporation of the water droplets. This makes it possible to prevent such water droplets from adhering to the bonded substrate W, or to reduce the amount of water droplets that adhere to the bonded substrate W.

[0085] In this embodiment, the light source 15 emits light toward a target region R2 within the light-receiving surface Wu of the bonded substrate W. When the light from the light source 15 is irradiated onto the target region R2, the target region R2 changes to the light-receiving region R3 that is actually irradiated with the light from the light source 15. The cooling device 21 blows cooling gas toward an area within the light-receiving surface Wu other than the target region R2. Therefore, the cooling gas directly hits areas other than the target region R2. If the cooling gas directly hits the light-receiving region R3 before the infrared camera 16 captures an image of the bonded substrate W, the temperature of the light-receiving region R3 may decrease compared to when the cooling gas is not directly hit, which may reduce the accuracy of defect detection. Therefore, by directly applying the cooling gas to areas other than the target region R2, the bonded substrate W can be efficiently cooled while reducing the temperature drop in the light-receiving region R3 that coincides with the target region R2.

[0086] In this embodiment, when the light source 15 emits light toward a target region R2 within the light-receiving surface Wu of the bonded substrate W, the target region R2 changes to a light-receiving region R3 that coincides with the target region R2. The cooling device 21 blows cooling gas toward an area within the light-receiving surface Wu other than the target region R2. After the infrared camera 16 captures an image of the light-receiving region R3, the actuator 17 moves the light-receiving region R3 to an area where the cooling gas directly hits the light-receiving surface Wu. This narrows the range within the bonded substrate W over which heat from the captured light-receiving region R3 moves.

[0087] In this embodiment, the actuator 17 changes the relative position of the target region R2 with respect to the bonded substrate W so that the target region R2 does not overlap with the light-receiving region R3, which is the region within the light-receiving surface Wu that was irradiated with light from the light source 15 in the most recent irradiation step, and the peripheral region R4, which is the region within the light-receiving surface Wu to which heat from the light-receiving region R3 is transferred. When the target region R2 overlaps with the light-receiving region R3 and the peripheral region R4 that were generated in the most recent irradiation step, a temperature change different from when the target region R2 does not overlap occurs. This can cause a decrease in defect detection accuracy. Therefore, by moving the target region R2 away from the light-receiving region R3 and the peripheral region R4 that were generated in the most recent irradiation step, a decrease in defect detection accuracy can be prevented.

[0088] In this embodiment, the gas inside the housing 10 is cooled while circulating within the housing 10. That is, the gas inside the housing 10 is caused to flow into the gas outlet 22 of the cooling device 21 and is cooled inside the housing 10 by the cooler 23 of the cooling device 21. While the gas flows into the gas outlet 22 and is cooled by the cooler 23, the cooled gas, i.e., the gas cooled by the cooler 23, is supplied into the housing 10 from the gas supply port 26 of the cooling device 21. The cooler 23 re-cools the gas that it itself has cooled. Therefore, the energy required to cool the gas can be reduced compared to when gas outside the housing 10 is cooled and then supplied into the housing 10.

[0089] In this embodiment, multiple sets of two substrates Wx are sequentially bonded by the bonding unit 2c. The defect inspection device 2d sequentially inspects the multiple sets of two substrates Wx bonded by the bonding unit 2c. The inspection of the bonded substrate W includes an irradiation step of irradiating the light receiving surface Wu of the bonded substrate W with light from the light source 15, an imaging step of imaging the light receiving surface Wu with the infrared camera 16, and a cooling step of causing the cooling device 21 to supply cooling gas into the housing 10. The bonded substrate W is two substrates Wx bonded by the bonding unit 2c.

[0090] The defect inspection device 2d completes inspection of at least one bonded substrate W before the bonding unit 2c begins bonding the final set of two substrates Wx among the multiple sets of two substrates Wx. Therefore, if a defect such as a void 40 is present in the bonded substrate W, this will be detected before the bonding unit 2c begins bonding the final set of two substrates Wx. Furthermore, because the bonding unit 2c and the defect inspection device 2d are provided in the substrate bonding apparatus 1, the time from bonding the two substrates Wx to inspection can be shortened compared to when these are separate devices.

[0091] For example, if the bonding unit 2c and the defect inspection device 2d are separate devices, the bonded substrate W must be transported from the bonding unit 2c to the load port LP for the bonding unit 2c and then loaded into a carrier CA on the load port LP. Furthermore, this carrier CA must be transported onto the load port LP for the defect inspection device 2d, and the bonded substrate W in the carrier CA must be transported from the load port LP to the defect inspection device 2d. Therefore, by providing the bonding unit 2c and the defect inspection device 2d in the substrate bonding device 1, the time from when the two substrates Wx are bonded to when they are inspected can be shortened.

[0092] If a bonded substrate W other than the last bonded substrate W has a defect, the production of defective bonded substrates W can be prevented by halting bonding in the bonding unit 2c. Changing the bonding conditions or the conditions of the processes performed before bonding can reduce the number of defective bonded substrates W. This increases the yield of bonded substrates W. In particular, because the time from bonding two substrates Wx to inspection can be shortened, measures such as halting the process can be taken more quickly than when the bonding unit 2c and the defect inspection device 2d are separate devices.

[0093] Next, another embodiment will be described.

[0094] When the irradiation process is performed multiple times, the control device 30 may change the position where the light from the light source 15 is irradiated onto the bonded substrate W so that the outer edge of the target region R2 coincides with the outer edge of the light-receiving region R3 created in the most recent irradiation process or is adjacent to the outer edge of the light-receiving region R3 created in the most recent irradiation process. This reduces the time required to inspect the bonded substrate W compared to when the target region R2 is moved away from the light-receiving region R3 created in the most recent irradiation process. In addition, if the defect to be detected is large, the defect can be detected in this manner as well.

[0095] If the defect inspection device 2d is part of a device having a function other than inspection of the bonded substrate W, a control device provided in the device, such as the control device 3, rather than the control device 30, may control the defect inspection device 2d.

[0096] Any two or more of the above-mentioned features may be combined. Any two or more of the above-mentioned steps may be combined.

[0097] Although the embodiments of the present invention have been described in detail, these are merely examples used to clarify the technical contents of the present invention, and the present invention should not be construed as being limited to these examples. The spirit and scope of the present invention are limited only by the appended claims. [Explanation of symbols]

[0098] 1: substrate bonding device, 2a: activation unit, 2b: cleaning unit, 2c: bonding unit, 2d: defect inspection device, 3: control device, 10: housing, 14: stage, 14x: X-direction stage, 14y: Y-direction stage, 15: light source, 16: infrared camera, 17: actuator, 17x: X-direction actuator, 17y: Y-direction actuator, 18: vibration isolation table, 21: cooling device, 22: gas outlet, 23: cooler, 24: fan, 25: housing, 26: gas supply port, 30: control device, 30d: defect determination application program, 40: void, 41: defective part, 42: healthy part, R1: imaging area, R2: target area, R3: light-receiving area, R4: surrounding area, W: bonded substrate, WL: non-light-receiving surface, Wu: light-receiving surface, Wx: substrate

Claims

1. a housing that houses a bonded substrate, which is two bonded substrates; a stage that supports or holds the bonded substrate within the housing; a light source that emits light toward a target area within a light receiving surface of the bonded substrate supported or held by the stage, thereby locally heating the bonded substrate; an infrared camera that detects a temperature distribution in the target area irradiated with light from the light source by capturing an image of the target area of ​​the bonded substrate supported or held by the stage; at least one actuator that moves the light source and / or the stage and the bonded substrate to change the position at which the light from the light source is irradiated on the bonded substrate supported or held by the stage; a cooling device that supplies cooling gas into the housing that is lower in temperature than the air temperature outside the housing, thereby forming a flow of the cooling gas within the housing and lowering the air temperature within the housing.

2. The defect inspection device according to claim 1 , wherein the cooling device blows out the cooling gas toward an area within the light-receiving surface other than the target area.

3. 3. The defect inspection device according to claim 2, wherein when an irradiation step of irradiating the light from the light source onto the light receiving surface of the bonded substrate supported or held by the stage is performed a plurality of times, the at least one actuator changes the relative positions of the stage and the bonded substrate with respect to the cooling device so that the cooling gas blown out from the cooling device directly hits the light receiving area after the infrared camera captures an image of a light receiving area, which is an area within the light receiving surface that was irradiated with the light from the light source in the most recent irradiation step.

4. 2. The defect inspection device according to claim 1, wherein when an irradiation step of irradiating the light from the light source onto the light receiving surface of the bonded substrate supported or held by the stage is performed a plurality of times, the at least one actuator changes a position where the light from the light source is irradiated onto the bonded substrate supported or held by the stage so that the target area does not overlap with a light receiving area, which is an area within the light receiving surface that was irradiated with the light from the light source in the most recent irradiation step, and a peripheral area, which is an area within the light receiving surface to which heat from the light receiving area is transferred.

5. The defect inspection device of any one of claims 1 to 4, wherein the cooling device includes a gas exhaust port through which gas enters the housing, a cooler that cools the gas that has entered the gas exhaust port within the housing, and a gas supply port that supplies the gas cooled by the cooler into the housing as the cooling gas.

6. a bonding unit that sequentially bonds a plurality of pairs of two substrates; a defect inspection device that sequentially inspects the plurality of sets of two substrates bonded by the bonding unit, The defect inspection device a housing that houses a bonded substrate, which is two substrates bonded by the bonding unit; a stage that supports or holds the bonded substrate within the housing; a light source that emits light toward a target area within a light receiving surface of the bonded substrate supported or held by the stage, thereby locally heating the bonded substrate; an infrared camera that detects a temperature distribution in the target area irradiated with light from the light source by capturing an image of the target area of ​​the bonded substrate supported or held by the stage; at least one actuator that moves the light source and / or the stage and the bonded substrate to change the position at which the light from the light source is irradiated on the bonded substrate supported or held by the stage; a cooling device that supplies a cooling gas that is lower in temperature than the temperature outside the housing into the housing, thereby forming a flow of the cooling gas inside the housing and lowering the temperature inside the housing, the defect inspection device completes inspection, including an irradiation step of irradiating the light receiving surface of the bonded substrate supported or held by the stage with light from the light source, an imaging step of imaging the light receiving surface irradiated with the light from the light source with the infrared camera, and a cooling step of causing the cooling device to supply the cooling gas into the housing, for at least one of the bonded substrates before the bonding unit starts bonding a final set of two substrates among the multiple sets of two substrates.

7. a preparation step of supporting or holding the bonded substrate, which is two bonded substrates, by a stage in a housing that accommodates the bonded substrate; a first irradiation step of locally heating the bonded substrate by emitting light from a light source toward a target area within a light receiving surface of the bonded substrate supported or held by the stage; a first photographing step of photographing the target area of ​​the bonded substrate supported or held on the stage with an infrared camera to detect a temperature distribution of the target area irradiated with the light from the light source in the first irradiation step; a cooling step of causing a cooling device to supply a cooling gas having a temperature lower than the temperature outside the housing into the housing after at least the infrared camera has photographed the target area, thereby forming a flow of the cooling gas inside the housing and lowering the temperature inside the housing; a first position changing step of changing a position at which the light from the light source is irradiated onto the bonded substrate supported or held by the stage by moving at least one of the light source and the stage and the bonded substrate using at least one actuator; a second irradiation step of locally heating the bonded substrate by emitting the light from the light source toward the target area after the position at which the light from the light source is irradiated on the bonded substrate supported or held by the stage is changed; a second photographing step of photographing the target area of ​​the bonded substrate supported or held by the stage with the infrared camera, thereby detecting a temperature distribution of the target area irradiated with light from the light source in the second irradiation step.

Images