JP7680301B2 - Light irradiation device and light irradiation method - Google Patents

Description

The technology disclosed in this specification relates to technology for detecting irradiated light.

Conventionally, optical processing technology has been used to process objects by irradiating them with light, such as laser light (see, for example, Patent Document 1).

JP 2006-272430 A

To improve the processing accuracy in the above optical processing technology, it is important that the position where the light is irradiated is controlled with high precision.

One method for detecting the position where light is irradiated is, for example, to detect the position where light is irradiated by capturing an image of the light with an area camera. However, there is a problem in that damage accumulates in the components or optical elements placed in the area where light is irradiated, reducing detection accuracy, especially when detecting high-intensity light such as laser light.

The technology disclosed in this specification was developed in consideration of the problems described above, and is a technology for suppressing the decrease in detection accuracy caused by irradiation with light.

A light irradiation device according to a first aspect of the technology disclosed in the present specification comprises a stage at least partially made of a transparent material, and at least one light irradiation unit for irradiating the upper surface of the stage with light, the stage being provided with a light-transmitting unit for transmitting the light, and at least one scattering unit for scattering the light, and further comprising a detection unit for detecting at least one of the light transmitted through the light-transmitting unit and the light scattered in the scattering unit, and an identification unit for identifying the position of at least one of the light-transmitting unit and the scattering unit based on the amount of light detected.

The light irradiation device, which is a second aspect of the technology disclosed in the present specification, is related to the light irradiation device, which is the first aspect, and the identification unit identifies the position of the boundary between the light transmitting portion and the scattering portion based on the difference in the amount of light detected.

The light irradiation device according to the third aspect of the technology disclosed in the present specification is related to the light irradiation device according to the first or second aspect, and the scattering section has a butterfly shape in which one vertex of each of two triangles is connected to each other when viewed from above the stage.

The fourth aspect of the technology disclosed in the present specification is related to the light irradiation device according to any one of the first to third aspects, and the light irradiated from the light irradiation unit is laser light.

The light irradiation device, which is a fifth aspect of the technology disclosed in the present specification, is related to any one of the light irradiation devices from the first to fourth aspects, and the detection unit includes a focusing lens for focusing at least one of the light transmitted through the light-transmitting unit and the light scattered in the scattering unit.

The light irradiation device, which is a sixth aspect of the technology disclosed in the present specification, is related to the light irradiation device, which is the fifth aspect, and further includes a chamber in which the stage is contained, the inside of the chamber is under a vacuum or reduced pressure atmosphere, and the detection unit further includes a fiber that propagates the light focused by the focusing lens to the outside of the chamber, and a photodetector that is disposed outside the chamber and detects the light propagated by the fiber.

A light irradiation method that is a seventh aspect of the technology disclosed in the present specification includes a step of irradiating light onto an upper surface of a stage made of a transparent material, the stage being provided with a light-transmitting section for transmitting the light and at least one scattering section for scattering the light, and further including a step of detecting at least one of the light that has transmitted through the light-transmitting section and the light that has been scattered in the scattering section, and a step of identifying the position of at least one of the light-transmitting section and the scattering section based on the amount of light detected.

According to at least the first and seventh aspects of the technology disclosed in the present specification, the scattering section onto which the light is irradiated is made of a transparent material, so that even when high-intensity light such as laser light is irradiated, damage to the area onto which the light is irradiated can be reduced. Therefore, the positional accuracy of the light detected by the detection section is less likely to decrease.

Furthermore, the objects, features, aspects and advantages associated with the technology disclosed in the present specification will become more apparent from the detailed description and accompanying drawings set forth below.

FIG. 1 is a perspective view illustrating an example of the configuration of a light irradiation device according to an embodiment. 2 is a cross-sectional view showing an example of the internal configuration and peripheral configuration of a vacuum chamber of a light irradiation device according to an embodiment. FIG. 3 is a perspective view mainly showing a light irradiation unit and a stage in the configuration exemplified in FIG. 2 . 3 is a cross-sectional view showing an example of the configuration mainly of a light irradiation unit and a stage from the configuration shown in FIG. 2 . 3A and 3B are schematic diagrams illustrating the configuration and operation of a light collecting unit. 3A and 3B are schematic diagrams illustrating the configuration and operation of a light collecting unit. 10A to 10C are plan views showing examples of the shape of the scattering portion. 8 is a diagram showing an example of a detection signal in a photodetector obtained when a scattering portion having the shape shown in FIG. 7 is scanned in the X-axis direction. FIG. FIG. 11 is a cross-sectional view showing an example of a configuration in which a plurality of light irradiation units are provided.

The following describes the embodiments with reference to the attached drawings. In the following embodiments, detailed features are shown to explain the technology, but these are merely examples and are not necessarily all essential features for the embodiments to be feasible.

The drawings are schematic, and for ease of explanation, configurations may be omitted or simplified as appropriate. Furthermore, the size and positional relationships of the configurations shown in different drawings are not necessarily described accurately, and may be changed as appropriate. Furthermore, hatching may be used in drawings that are not cross-sectional views, such as plan views, to make it easier to understand the contents of the embodiments.

In addition, in the following description, similar components are illustrated with the same reference symbols, and their names and functions are also similar. Therefore, detailed descriptions of them may be omitted to avoid duplication.

In addition, in the description of this specification, when a certain component is described as "comprising," "including," or "having," unless otherwise specified, this is not an exclusive expression that excludes the presence of other components.

In addition, even if ordinal numbers such as "first" or "second" are used in the description of this specification, these terms are used for convenience to facilitate understanding of the contents of the embodiments, and the contents of the embodiments are not limited to the order that may result from these ordinal numbers.

In addition, in the description of this specification, expressions such as "positive direction of the ... axis" or "negative direction of the ... axis" refer to the direction along the arrow of the ... axis shown in the figure as the positive direction, and the direction opposite the arrow of the ... axis shown in the figure as the negative direction.

In addition, in the explanations given in this specification, expressions indicating relative or absolute positional relationships, such as "in one direction," "along one direction," "parallel," "orthogonal," "center," "concentric," or "coaxial," are intended to include cases in which the positional relationship is strictly indicated, as well as cases in which the angle or distance is displaced within a tolerance or within a range in which the same level of functionality is obtained, unless otherwise specified.

In addition, even if the descriptions in this specification use terms that indicate specific positions or directions, such as "top," "bottom," "left," "right," "side," "bottom," "front," or "back," these terms are used for convenience to facilitate understanding of the contents of the embodiments, and do not relate to the positions or directions when the embodiments are actually implemented.

<Embodiment>
The light irradiation device according to the present embodiment will be described below. Note that, in the following embodiment, a light irradiation device in which the inside of the chamber is a vacuum or a reduced pressure atmosphere is described as an example, but the present invention can also be applied to a case in which the inside of the chamber is not a vacuum.

<Configuration of the Light Irradiation Device>
Fig. 1 is a perspective view showing a schematic example of the configuration of a light irradiation device 1 according to the present embodiment. In Fig. 1, a chamber frame supporting a vacuum chamber 12, wiring actually connected thereto, and the like are omitted for convenience. Note that, although the "vacuum" in the present embodiment is preferably a high vacuum (for example, 0.00001 Pa) to prevent deterioration of the characteristics of the substrate W, it also includes a vacuum degree that does not reach the high vacuum.

1, the light irradiation device 1 includes a vacuum chamber 12, an external fixed part 14 such as a stone surface plate, a bellows 16A which is an elastic member made of, for example, stainless steel and connects the vacuum chamber 12 and the external fixed part 14, a light irradiation part 18 which irradiates light into the vacuum chamber 12, a vacuum pump 21 which reduces the pressure inside the vacuum chamber 12 to create a vacuum state, and a control part 22 which controls each of the driving parts of the light irradiation device 1. In the above, a bellows made of stainless steel or the like is shown as an example of the elastic member, but an elastic member made of a metal other than stainless steel or an elastic member made of resin or the like may be used depending on the required specifications. In addition, the shape of the elastic member does not have to be a bellows shape like the above bellows 16A.

The vacuum chamber 12 has a space therein in which a substrate W is housed. The substrates W to be processed include, for example, semiconductor wafers, glass substrates for liquid crystal display devices, substrates for flat panel displays (FPDs) such as organic electroluminescence (EL) display devices, substrates for optical disks, substrates for magnetic disks, substrates for magneto-optical disks, glass substrates for photomasks, ceramic substrates, substrates for field emission displays (FEDs), or substrates for solar cells. The substrate W is, for example, a substrate with a thin film formed on its upper surface.

In addition, an opening 12A is formed on the side of the vacuum chamber 12, through which the substrate W passes when being loaded and unloaded. The opening 12A is appropriately closed when the vacuum chamber 12 is in a vacuum state. Other components housed inside the vacuum chamber 12 will be described later.

The light irradiation unit 18 irradiates light toward the upper surface of the substrate W accommodated in the vacuum chamber 12. At this time, the substrate W is aligned in advance by the detection unit 62 described later or the like. The light irradiation unit 18 performs ablation processing of the substrate W by irradiating it with, for example, laser light. The light irradiation unit 18 may irradiate light such as an electron beam depending on the purpose of processing or the like. The light irradiation unit 18 irradiates light from outside the vacuum chamber 12 to the upper surface of the substrate W accommodated in the vacuum chamber 12 through an irradiation window (transparent plate made of quartz or the like) not shown. Then, the substrate W in the vacuum chamber 12 moves relative to the light irradiation unit 18, or the light scans the upper surface of the substrate W by controlling the optical system in the light irradiation unit 18. The light irradiation unit 18 is also disposed on the upper surface of a stand 24 fixed to the external fixed unit 14.

The control unit 22 may include a storage device including a memory (storage medium) such as a hard disk drive (HDD), a random access memory (RAM), a read only memory (ROM), a flash memory, a volatile or non-volatile semiconductor memory, a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, or a DVD, a processing circuit such as a central processing unit (CPU) that executes a program stored in the storage device, an external CD-ROM, an external DVD-ROM, or an external flash memory, an input device that can input information such as a mouse, a keyboard, a touch panel, or various switches, and an output device that can output information such as a display, a liquid crystal display device, or a lamp.

The control unit 22 controls the output of the light source in the light irradiation unit 18 and the direction in which the light is irradiated, or controls the output of the vacuum pump 21, and also controls the drive of each drive unit (e.g., the drive unit of the linear motor mechanism or the drive unit of the lift pin mechanism) described below. In addition, the control unit 22 can identify the position of the stage on which the substrate W is placed based on the detection value of the light irradiated from the light irradiation unit 18, as described below.

2 is a cross-sectional view showing an example of the internal configuration and peripheral configuration of the vacuum chamber 12 of the light irradiation device 1 according to the present embodiment. As shown in FIG. 2, the inside of the vacuum chamber 12 includes a stage 42 on the upper surface of which the substrate W is placed, a slider 44 that is movable in the Y-axis direction and supports the stage 42 from below, a base 46 that is fixed to the external fixing part 14 independently of the vacuum chamber 12, a linear guide 48 that is fixed to the base 46 and extends in the Y-axis direction, a linear motor mechanism 50 that moves the slider 44 in the Y-axis direction along the linear guide 48, a lift pin mechanism 52 having lift pins 52A that pass through through holes (not shown here) formed in the stage 42 and support the substrate W, and a detection unit 62 that is disposed below the stage 42 (Z-axis negative direction side in FIG. 2).

The stage 42 holds the substrate W approximately horizontally with the processing surface of the substrate W facing upward. The detailed configuration of the stage 42 will be described later. A slider 44 supporting the stage 42 is moved in the Y-axis direction by a linear motor mechanism 50, and the light irradiated from the light irradiator 18 is scanned in the X-axis direction, so that the entire surface of the processing area of the substrate W can be scanned with light in a planar view. Alternatively, the light irradiated from the light irradiator 18 is scanned in the X-axis and Y-axis directions, so that the entire surface of the processing area of the substrate W can be scanned with light in a planar view. The lift pin mechanism 52 is fixed to the base 46.

The linear motor mechanism 50 is fixed to the external fixed part 14 located to the side of the vacuum chamber 12 through an opening 12B formed in the side of the vacuum chamber 12. Specifically, the linear motor mechanism 50 is fixed to the end of a hollow columnar member 14A that passes through a bellows 16A welded to the opening 12B. At this time, wiring and the like connected to the linear motor mechanism 50 are led out to the outside of the vacuum chamber 12 through the inside of the columnar member 14A. The columnar member 14A included in the external fixed part 14 is fixed to an external member 14B included in the external fixed part 14. Furthermore, the columnar member 14A does not come into contact with the bellows 16A connected to the side of the vacuum chamber 12.

The base 46 is fixed to the external fixed part 14 located below the vacuum chamber 12 through an opening 12C formed in the bottom surface of the vacuum chamber 12. Specifically, the base 46 is fixed to the end of a columnar member 14C that passes through a bellows 16B welded to the opening 12C. The columnar member 14C included in the external fixed part 14 is fixed to an external member 14B included in the external fixed part 14. Furthermore, the columnar member 14C does not come into contact with the bellows 16B connected to the bottom surface of the vacuum chamber 12.

In FIG. 2, the external fixed parts 14 are arranged across the sides and below the vacuum chamber 12, but it is not essential that the external fixed parts 14 are continuous at these positions; they may be provided dispersedly at these positions, or may be provided at only one of the positions. The vacuum chamber 12 is supported and fixed from below in the vertical direction by a chamber frame (not shown) separate from the bellows 16B, but the chamber frame is provided independently of the external fixed parts 14.

The detection unit 62 is capable of detecting the light irradiated from the light irradiation unit 18 below the stage 42. The detailed configuration of the detection unit 62 will be described later.

Figure 3 is a perspective view mainly showing the light irradiation unit 18 and stage 42 of the configuration shown in Figure 2. Figure 3 shows a state in which a substrate W is placed on the upper surface of the stage 42. The light irradiation unit 18 can scan the light irradiation direction in the X-axis direction in Figure 3, and the stage 42 can move in the Y-axis direction by a linear motor mechanism 50 (see Figure 2). Therefore, the light irradiated from the light irradiation unit 18 to the upper surface of the stage 42 can form a rectangular irradiation area (light irradiation area) on the upper surface of the substrate W.

As shown in FIG. 3, the stage 42 has an object placement area 42A in which the substrate W, which is the object to be irradiated with light by the light irradiation unit 18, is placed, and a position calibration area 42B in which the position of the light irradiated by the light irradiation unit 18 is calibrated.

The target placement area 42A places the substrate W at a specific position within the target placement area 42A. This allows the positional relationship between the stage 42 and the substrate W to be specified in advance. In the position calibration area 42B, the position of the light irradiated from the light irradiation unit 18 into the position calibration area 42B is detected by the detection unit 62 (see FIG. 2). Then, in the position calibration area 42B, prior to optical processing of the substrate W in the target placement area 42A, the correspondence between the set value of the direction of the light irradiated from the light irradiation unit 18 and the irradiation position of the detected light is calibrated.

A light-transmitting section 142 that transmits light is provided in at least a portion of the position calibration area 42B. The light-transmitting section 142 is made of a transparent material such as a glass material (SiO ₂ ) or a transparent resin (e.g., silicone resin). The light-transmitting section 142 is provided from the upper surface to the lower surface of the stage 42 corresponding to the position calibration area 42B. The light irradiated from the light irradiating section 18 to the light-transmitting section 142 is transmitted from the upper surface to the lower surface of the stage 42.

At least one scattering section 142A (two in FIG. 3) is provided in at least a part of the light-transmitting section 142. The scattering section 142A is made of a transparent material, and reflects or transmits the irradiated light while scattering it. The position where the scattering section 142A is provided is a specific position on the stage 42. That is, the position of the scattering section 142A in the entire stage 42 is specified in advance. In FIG. 3, each scattering section 142A is disposed at the end of the light irradiation area of the light irradiation section 18 in the X-axis direction, but the position where the scattering section 142A is disposed may be any specific position on the stage 42 and is not limited to the end of the light irradiation area of the light irradiation section 18. The scattering section 142A has the property of scattering incident light, and can be obtained, for example, by blasting a glass material or by frosting using hydrofluoric acid or the like. In FIG. 3, each scattering portion 142A is formed on the upper surface of the light-transmitting portion 142, but at least one scattering portion 142A may be formed on the lower surface of the light-transmitting portion 142.

In the case shown in FIG. 3, the target placement area 42A and the position calibration area 42B are separate areas, but these areas may overlap at least partially. That is, a light-transmitting section 142 may be provided in at least a portion of the area where the substrate W is placed. In such a case, for example, when the substrate W is not placed, calibration of the position of the light irradiated from the light irradiation section 18 may be performed at the position where the substrate W is placed.

In addition, the light-transmitting section 142 may have a scattering section 142A formed over its entire range. In other words, there may be no part through which light only passes, and light may be scattered over the entire range of the light-transmitting section 142.

In addition, in FIG. 3, the light-transmitting portion 142 is provided extending in the X-axis direction, and a scattering portion 142A is provided at each end in the X-axis direction, but the light-transmitting portion 142 may be divided into multiple locations in the X-axis direction. However, when multiple scattering portions 142A are provided in the integrally formed light-transmitting portion 142 (i.e., as shown in FIG. 3), the light-transmitting portion 142 can be attached to the stage 42 (fitted in the case of FIG. 3) while maintaining the positional accuracy between the multiple scattering portions 142A when the light-transmitting portion 142 is manufactured from a transparent material. Therefore, since no positional deviation occurs between the scattering portions 142A when attached to the stage 42, the accuracy of the calibration performed using the multiple scattering portions 142A can be maintained at a high level.

Figure 4 is a cross-sectional view showing an example of the configuration of the light irradiation unit 18 and the stage 42, among the configurations shown in Figure 2. As shown in Figure 4, the light irradiation unit 18 includes a scanner 18A, such as a galvanometer mirror or a polygon mirror, that controls the direction of the irradiated light in the X-axis and Y-axis directions, and a condenser lens 18B that condenses light from a light source (not shown). In Figure 4, the light irradiated through the condenser lens 18B and the irradiation window 20 made of quartz or the like is, for example, laser light 18C. The laser light 18C can scan the substrate W placed on the upper surface of the stage 42 in the X-axis direction by controlling the scanner 18A. Here, it is preferable that the light irradiation unit 18 can control light in the X-axis and Y-axis directions, but the light irradiation unit 18 may be capable of controlling light in either the X-axis or Y-axis direction.

The stage 42 has a light-transmitting portion 142 formed in the position calibration area 42B (see FIG. 3) and a scattering portion 142A formed on the upper surface of the light-transmitting portion 142. The laser light 18C irradiated from the light irradiating portion 18 can be scanned in the X-axis direction in a range that reaches at least the scattering portion 142A.

A detection section 62 for detecting light is disposed below the stage 42. The detection section 62 includes a focusing unit 62A that focuses light within the vacuum chamber 12, a fiber 62B that propagates the light focused by the focusing unit 62A outside the vacuum chamber 12, and a photodetector 62C that detects the light propagated outside the vacuum chamber 12 by the fiber 62B. Because the photodetector 62C is disposed outside the vacuum chamber 12, it is possible to prevent gas that may be released from the photodetector 62C from entering the vacuum chamber 12.

Figures 5 and 6 are schematic diagrams showing the configuration and operation of the focusing unit 62A. As shown in the examples of Figures 5 and 6, the focusing unit 62A includes a focusing lens 162 that focuses the light incident from the light irradiation unit 18 (see Figure 4) on the optical axis of the light.

In the case shown in FIG. 5, the laser light 18C (parallel light) incident from the light irradiation unit 18 (see FIG. 4) passes only through the light transmitting portion 142 on the stage 42 to reach the light collecting unit 62A. On the other hand, in the case shown in FIG. 6, the laser light 18C incident from the light irradiation unit 18 (see FIG. 4) passes through the scattering portion 142A and the light transmitting portion 142 on the stage 42 to reach the light collecting unit 62A. Note that, although the laser light 18C passes through the scattering portion 142A and the light transmitting portion 142 in FIG. 6, the laser light 18C may pass only through the scattering portion 142A.

In the case shown in FIG. 5, the laser light 18C that passes through the light-transmitting portion 142 other than the scattering portion 142A reaches the focusing unit 62A without a significant change in the irradiation range and direction of the light. Then, most of the laser light 18C is focused by the focusing lens 162 in the focusing unit 62A and enters the fiber 62B that is positioned at the focusing position of the focusing lens 162.

On the other hand, in the case shown in FIG. 6, laser light 18C passing through scattering section 142A in transparent section 142 is scattered as it passes through scattering section 142A. As a result, laser light 18C reaches focusing unit 62A with the irradiation range of laser light 18C expanded by the scattered light (the sandy area in FIG. 6). Laser light 18C is then focused by focusing lens 162 in focusing unit 62A.

At this time, the laser light 18C, whose irradiation range has expanded due to light scattering in the scattering section 142A, contains many components that are not parallel light, and at least some of the components are not focused at the focusing position of the focusing lens 162. Therefore, only a portion of the laser light 18C reaches the fiber 62B, excluding the laser light 18C that is not focused at the focusing position.

As described above, when the laser light 18C irradiated onto the upper surface of the stage 42 passes through the light-transmitting portion 142 other than the scattering portion 142A, most of the light is focused by the focusing lens 162 and reaches the fiber 62B, and when the laser light 18C passes through the scattering portion 142A of the light-transmitting portion 142, only a portion of the light is focused by the focusing lens 162 and reaches the fiber 62B. The light that reaches the fiber 62B is then detected by the photodetector 62C (see FIG. 4).

Therefore, the amount of light of the laser light 18C detected by the detection unit 62 (see FIG. 4) differs between when the laser light 18C is irradiated to the light-transmitting portion 142 other than the scattering portion 142A and when the laser light 18C is irradiated to the scattering portion 142A. Therefore, based on the light amount value output from the photodetector 62C, the control unit 22 can determine the timing at which the detected light amount changes as the timing at which the light is irradiated to the boundary in the light-transmitting portion 142 where the scattering portion 142A is formed. Furthermore, the control unit 22 can calibrate the position of the irradiated light by making the setting value of the scanner 18A (see FIG. 4) at that timing correspond to the position of the scattering portion 142A (specifically, the boundary position). As a result, when the substrate W placed on the upper surface of the stage 42 is optically processed in a later process, the position of the light irradiated from the light irradiation unit 18 can be aligned with high accuracy by the control of the control unit 22.

In addition, since the light-transmitting portion 142 onto which light is irradiated by the light irradiation unit 18 is made of a transparent material, even when the light-transmitting portion 142 is repeatedly irradiated with light of a relatively high intensity in order to calibrate the position of the light irradiated by the light irradiation unit 18, damage to the target onto which light is irradiated for calibration (i.e., the light-transmitting portion 142) can be suppressed.

<Shape of the scattering part>
7 is a plan view showing an example of the shape of the scattering section 142A. As shown in FIG. 7, the scattering section 142A is provided on the upper surface of the stage 42 (see FIG. 3 and FIG. 4) spreading in the X-axis direction and the Y-axis direction, and can be formed, for example, in a shape (butterfly shape) in which two triangles are arranged facing each other in a plan view and one vertex of each triangle is connected. In such a shape, the width of the scattering section 142A in the X-axis direction (the total width of the formed area) becomes larger toward the center in the Y-axis direction. Alternatively, the width of the scattering section 142A in the Y-axis direction becomes smaller toward the center in the X-axis direction.

Figure 8 is a diagram showing an example of a detection signal at the photodetector 62C (see Figure 4) obtained when the scattering portion 142A, the shape of which is shown in Figure 7, is scanned in the X-axis direction. In the example shown in Figure 8, the photodetector 62C detects light at regular sampling times (T1, T2, T3, T4, and T5) and outputs a detection signal S, and the position of the stage 42 (see Figures 3 and 4) in the Y-axis direction is changed for each scan. Of the detection signals S shown in Figure 8, black indicates a strong signal strength (i.e., a large amount of light is detected), and white indicates a weak signal strength (i.e., a small amount of light is detected).

When the light irradiated to the butterfly-shaped scattering portion 142A (see FIG. 7) is detected by the photodetector 62C, as shown in the example in FIG. 8, at the end on the positive side of the Y axis and the end on the negative side of the Y axis, the areas with weak signal strength are arranged in two separate locations in the X axis direction, so that the intensity of the detection signal S fluctuates (varies) around sampling timing T3 in the period between sampling timing T1 and sampling timing T5. On the other hand, at the center in the Y axis direction, the areas with weak signal strength are arranged continuously in the X axis direction, so that the intensity of the detection signal S does not fluctuate in the period between sampling timing T1 and sampling timing T5.

Then, it can be seen that the position in the Y-axis direction during the scan where the detection signal S did not fluctuate is the central position in the Y-axis direction of the scattering section 142A. In other words, by comparing the fluctuations of the detection signal S over multiple scans, the central position of the scattering section 142A can be identified with high accuracy.

It can also be seen that the position in the X-axis direction corresponding to the midpoint of the period in which the intensity of the detection signal S is weak (including the period in which it is continuously weak and the period in which it is intermittently weak) is the central position in the X-axis direction of the scattering section 142A. In other words, when the detection signal S is output at sampling timing T1 and sampling timing T5, it can be seen that the central position is sampling timing T3.

On the other hand, when a scattering section (butterfly shape) that is a shape obtained by rotating the example shown in FIG. 7 by 90 degrees is scanned in the X-axis direction (this corresponds to scanning a scattering section that is a shape shown in FIG. 7 in the Y-axis direction), long and continuous areas of weak signal strength are arranged in the X-axis direction at the ends on the positive side of the Y-axis and the ends on the negative side of the Y-axis, and the area of weak signal strength is arranged in the center in the Y-axis direction and is the shortest in the X-axis direction.

Then, it can be seen that the position in the Y-axis direction during the scan in which the detection signal S with the weakest signal strength was detected for the shortest time is the central position in the Y-axis direction of the scattering area. In other words, by comparing the length of time that the signal strength weakens over multiple scans, the central position of the scattering area can be identified with high accuracy.

It can also be seen that the position in the X-axis direction corresponding to the midpoint of the period in which the detection signal S becomes weak (sampling time T3 if the detection signal S is output from sampling time T1 to sampling time T5) is the center position in the X-axis direction of the scattering section.

In this way, because the scattering section has a butterfly shape, the central position of the scattering section in the X-axis direction or Y-axis direction can be determined with high accuracy. Therefore, the position of the light irradiated from the light irradiating section 18 (see FIG. 4) can be calibrated and aligned with high accuracy.

The shape of the scattering portion is not limited to the area gradually becoming smaller toward the center in the X-axis direction as shown in Figures 7 and 8, but may be, for example, an area discontinuously smaller toward the center in the X-axis direction, or an area larger toward the center in both the X-axis and Y-axis directions. In addition, the shape of the outer edge of the scattering portion is not limited to a straight line as shown in Figures 7 and 8, but may include at least a curved line in part.

<When multiple light irradiation units are provided>
9 is a cross-sectional view showing an example of a configuration in which a plurality of light irradiation units are provided. As shown in the example in FIG. 9, a plurality of light irradiation units 118 and light irradiation units 218 are provided in the light irradiation device.

The light irradiation unit 118 includes a scanner 118A, such as a galvanometer mirror that controls the direction of the irradiated light in the X-axis direction, and a condenser lens 118B that condenses light from a light source (not shown). In FIG. 9, the light irradiated through the condenser lens 118B and the irradiation window 20A formed of quartz or the like is, for example, laser light 118C, which can scan the substrate W placed on the upper surface of the stage 42 in the X-axis direction by controlling the scanner 118A.

Similarly, the light irradiation unit 218 includes a scanner 218A, such as a galvanometer mirror that controls the direction of the irradiated light in the X-axis direction, and a condenser lens 218B that condenses light from a light source (not shown). In FIG. 9, the light irradiated through the condenser lens 218B and further through the irradiation window 20B formed of quartz or the like is, for example, laser light 218C, which can scan the substrate W placed on the upper surface of the stage 42 in the X-axis direction by the control of the scanner 218A.

Here, the light irradiation area in the X-axis direction of the light irradiation unit 118 is from a position corresponding to the scattering section 142B formed in the light-transmitting section 142 to a position corresponding to the scattering section 142C formed in the light-transmitting section 142. On the other hand, the light irradiation area in the X-axis direction of the light irradiation unit 118 is from a position corresponding to the scattering section 142C formed in the light-transmitting section 142 to a position corresponding to the scattering section 142D formed in the light-transmitting section 142. In other words, the scattering section 142C is disposed at the connection portion between the light irradiation area of the light irradiation unit 118 and the light irradiation area of the light irradiation unit 218.

The detection units 62 are disposed below the stage 42 at positions corresponding to the scattering units 142B, 142C, and 142D, respectively. The light collecting unit 62A in each detection unit 62 is disposed on the optical axis of the light incident from the corresponding light irradiation unit.

By arranging scattering section 142B, scattering section 142C, and scattering section 142D in this manner, the connection portion between the light irradiation area of light irradiation section 118 and the light irradiation area of light irradiation section 218 is positioned by common scattering section 142C, so that misalignment between the two light irradiation areas can be suppressed.

<Effects of the above-described embodiment>
Next, examples of effects produced by the above-described embodiments are shown. In the following description, the effects are described based on the specific configurations shown as examples in the above-described embodiments, but they may be replaced with other specific configurations shown as examples in the present specification as long as the same effects are produced. In other words, for convenience, only one of the corresponding specific configurations may be described as a representative below, but the representatively described specific configuration may be replaced with another corresponding specific configuration.

According to the embodiment described above, the light irradiation device includes a stage 42, at least one light irradiation unit 18 (or light irradiation unit 118, light irradiation unit 218), and a determination unit. Here, the determination unit corresponds to, for example, the control unit 22. At least a part of the stage 42 is made of a transparent material. The light irradiation unit 18 irradiates the upper surface of the stage 42 with light. The stage 42 is provided with a light-transmitting unit 142 for transmitting light and at least one scattering unit 142A (or scattering unit 142B, scattering unit 142C, scattering unit 142D) for scattering light. The detection unit 62 detects at least one of the light transmitted through the light-transmitting unit 142 and the light scattered in the scattering unit 142A. The control unit 22 determines the position of at least one of the light-transmitting unit 142 and the scattering unit 142A based on the amount of light detected.

According to this configuration, since the scattering section 142A to which light is irradiated is made of a transparent material, even when high-intensity light such as laser light is irradiated, damage to the part to which light is irradiated (scattering section 142A) can be reduced. Therefore, the positional accuracy of the light detected by the detection section 62 is less likely to decrease. In addition, by detecting both the transmitted light that passes only through the light-transmitting section 142 and the scattered light that passes through the scattering section 142A with the detection section 62, a sufficient amount of light can be obtained to maintain the detection accuracy. In addition, since the irradiation range of the light scattered by the scattering section 142A is wider than that of the light that passes through the light-transmitting section 142, the amount of light incident on the fiber 62B is reduced overall. Therefore, based on the difference between the amount of transmitted light and the amount of scattered light, it can be determined whether the light detected by the detection section 62 is light that has passed through the light-transmitting section 142 or light that has been scattered in the scattering section 142A. Therefore, it is possible to specify whether the scattering section 142A is located at the position of the upper surface of the stage 42 to which light is irradiated. That is, the position of at least one of the light transmitting section 142 and the scattering section 142A can be identified.

The same effect can be achieved even if other configurations, examples of which are shown in this specification, are added to the above configuration, i.e., other configurations in this specification that are not mentioned as the above configuration are added.

Furthermore, according to the embodiment described above, the control unit 22 identifies the position of the boundary between the light transmitting section 142 and the scattering section 142A based on the difference in the amount of light detected. With this configuration, the position where the amount of detected light changes can be identified as the position of the boundary between the light transmitting section 142 and the scattering section 142A based on the difference between the amount of transmitted light and the amount of scattered light.

Furthermore, according to the embodiment described above, the scattering section 142A has a butterfly shape in which one vertex of each of two triangles is connected when viewed from above on the stage 42. With this configuration, it is possible to determine the center position of the scattering section 142A when the detection signal S does not fluctuate, or when the midpoint of the period during which the intensity of the detection signal S is weak is the center position of the scattering section 142A. In other words, by comparing the intensity of the detection signal S detected in multiple scans, the center position of the scattering section 142A can be identified with high accuracy.

Furthermore, according to the embodiment described above, the light irradiated from the light irradiating unit 18 is laser light. With this configuration, damage to the scattering unit 142A is reduced even when high-intensity light such as laser light is irradiated.

Furthermore, according to the embodiment described above, the detection unit 62 includes a condensing lens 162. The condensing lens 162 condenses at least one of the light transmitted through the light transmitting unit 142 and the light scattered in the scattering unit 142A. With this configuration, the amount of light required to maintain detection accuracy can be easily ensured by condensing the light.

According to the embodiment described above, the light irradiation device includes a chamber in which the stage 42 is contained. Here, the chamber corresponds to, for example, the vacuum chamber 12. Here, the inside of the vacuum chamber 12 is under a vacuum or reduced pressure atmosphere. The detection unit 62 includes a fiber 62B and a photodetector 62C. The fiber 62B propagates the light collected by the collecting lens 162 to the outside of the vacuum chamber 12. The photodetector 62C is disposed outside the vacuum chamber 12 and detects the light propagated by the fiber 62B. According to this configuration, since the photodetector 62C of the detection unit 62 is provided outside the vacuum chamber 12, it is possible to prevent outgassing emitted from the photodetector 62C from entering the vacuum chamber 12.

According to the embodiment described above, in the light irradiation method, light is irradiated onto the upper surface of the stage 42 made of a transparent material. Here, the stage 42 is provided with a light-transmitting section 142 for transmitting light, and at least one scattering section 142A for scattering light. Then, at least one of the light transmitted through the light-transmitting section 142 and the light scattered in the scattering section 142A is detected. Then, the position of at least one of the light-transmitting section 142 and the scattering section 142A is identified based on the amount of light detected.

According to this configuration, since the scattering section 142A to which light is irradiated is made of a transparent material, even when high-intensity light such as laser light is irradiated, damage to the area to which light is irradiated (scattering section 142A) can be reduced. Therefore, the positional accuracy of the light detected by the detection section 62 is unlikely to decrease. In addition, by detecting both the transmitted light that passes only through the light-transmitting section 142 and the scattered light that passes through the scattering section 142A with the detection section 62, a sufficient amount of light can be obtained to maintain the detection accuracy. In addition, based on the difference between the amount of transmitted light and the amount of scattered light, it can be determined whether the light detected by the detection section 62 is light that has passed through the light-transmitting section 142 or light that has been scattered in the scattering section 142A. Therefore, the position of at least one of the light-transmitting section 142 and the scattering section 142A can be specified.

Furthermore, the same effect can be achieved even if other configurations, examples of which are shown in this specification, are appropriately added to the above configuration, i.e., other configurations in this specification that were not mentioned as the above configuration are appropriately added.

<Modifications of the above-described embodiments>
In the embodiments described above, the material, composition, dimensions, shape, relative positional relationship, or implementation conditions of each component may be described, but these are merely examples in all respects and are not limiting.

Thus, numerous variations and equivalents not shown are contemplated within the scope of the technology disclosed in this specification. For example, this includes modifying, adding, or omitting at least one component.

In addition, in the embodiments described above, when a material name is mentioned without being specifically specified, it is assumed that the material in question contains other additives, such as alloys, unless a contradiction arises.

REFERENCE SIGNS LIST 1 Light irradiation device 18 Light irradiation section 18B Condenser lens 18C Laser light 42 Stage 62 Detection section 62B Fiber 62C Photodetector 118 Light irradiation section 118B Condenser lens 118C Laser light 142 Light transmitting section 142A Scattering section 142B Scattering section 142C Scattering section 142D Scattering section 162 Condenser lens 218 Light irradiation section 218B Condenser lens 218C Laser light

Claims (7)

a stage at least partially made of a transparent material;
at least one light irradiation unit for irradiating a top surface of the stage with light;
the stage is provided with a light transmitting section for transmitting the light and at least one scattering section for scattering the light,
a detection unit for detecting at least one of the light transmitted through the light transmitting unit and the light scattered by the scattering unit;
and an identifying unit that identifies a position of at least one of the light transmitting unit and the light scattering unit based on the amount of light detected.
Light irradiation device. The light irradiation device according to claim 1,
the identifying unit identifies a position of a boundary between the light transmitting unit and the scattering unit based on a difference in the amount of light detected.
Light irradiation device. The light irradiation device according to claim 1 or 2,
The scattering section has a butterfly shape in which one vertex of two triangles is connected to each other in a plan view of the stage.
Light irradiation device. A light irradiation device according to any one of claims 1 to 3,
The light irradiated from the light irradiation unit is laser light.
Light irradiation device. A light irradiation device according to any one of claims 1 to 4,
the detection unit includes a condenser lens for condensing at least one of the light transmitted through the light transmitting unit and the light scattered in the scattering unit;
Light irradiation device. The light irradiation device according to claim 5,
a chamber containing the stage;
The inside of the chamber is a vacuum or a reduced pressure atmosphere,
The detection unit is
a fiber that propagates the light focused by the focusing lens to the outside of the chamber;
a photodetector disposed outside the chamber and configured to detect the light transmitted by the fiber.
Light irradiation device. A step of irradiating a top surface of a stage made of a transparent material with light is provided,
the stage is provided with a light transmitting section for transmitting the light and at least one scattering section for scattering the light,
detecting at least one of the light transmitted through the light transmitting portion and the light scattered at the scattering portion;
and identifying a position of at least one of the light transmitting portion and the light scattering portion based on the amount of light detected.
Light irradiation method.

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