WO2002097366A1

WO2002097366A1 - Observation device using light and x-ray, exposure system and exposure method

Info

Publication number: WO2002097366A1
Application number: PCT/JP2002/005083
Authority: WO
Inventors: Tsutomu Nagai; Tomoyuki Suzuki
Original assignee: Hamamatsu Photonics K.K.
Priority date: 2001-05-25
Filing date: 2002-05-24
Publication date: 2002-12-05
Also published as: JP2002350111A; TW560236B

Abstract

An X-ray (5a) beamed onto a substrate (15) serving as a circuit board forms a fluorescent image as an alignment mark of the substrate (15) on a scintillator film (19). A visible ray (21a) shone onto a mask substrate (17) forms a projection image as an alignment mark of the mask substrate (17) on the scintillator film (19). A CCD camera (6) picks up these images.

Description

Itoda »

Observation apparatus, exposure apparatus and exposure method using light and X-rays

The present invention relates to, for example, an observation apparatus used for aligning a mask substrate and a substrate serving as a circuit board, an exposure apparatus including the observation apparatus, and an exposure method.

Background art

As a conventional example of an observation device using light and X-rays, there is a technology disclosed in Japanese Patent Application Laid-Open No. 11-330710. This publication discloses an X-ray generator that irradiates the core substrate with X-rays, an X-ray imaging device that captures an alignment mark on the core substrate, a halogen light source that irradiates the mask substrate with visible light, and a mask substrate. And an imaging device for imaging the alignment mark.

Also, Japanese Patent Application Laid-Open No. H5-2322803 discloses an X-ray light source for irradiating a sample on which a metal plate is formed with X-rays, and a visible light source for irradiating a resin plate with a mark formed thereon with visible light. And an image sensor for imaging a mark formed on a metal plate and a resin plate formed on a sample. This imaging device can capture both visible light and X-rays.

Japanese Unexamined Patent Publication No. Hei 6-2281595 describes an X-ray tube for irradiating a multilayer substrate with X-rays, an X-ray camera for imaging the inside of the multilayer substrate, and an I-beam mounted on the surface of the multilayer substrate. . And a CCD camera that captures an optical image of a chip or the like.

Disclosure of the invention

According to the technology disclosed in the above-mentioned Japanese Patent Application Laid-Open No. Hei 11-33010 and Japanese Patent Application Laid-Open No. Hei 6-28159, an image sensor for visible light and an image sensor for X-ray, An image sensor is required. Further, according to the technique disclosed in Japanese Patent Application Laid-Open No. 5-322803, an imaging device needs to have a function of imaging both visible light and X-rays.

An object of the present invention is to provide an image formed by irradiating light (at least one of visible light, ultraviolet light, and infrared light) and X-ray irradiation Provided are an observation device, an exposure device including the same, and an exposure method that can observe any of the images formed by the imaging device with a single imaging device and do not require the imaging device to have an X-ray imaging function. It is to be.

The observation device of the present invention includes: a light irradiation unit that irradiates at least one of visible light, ultraviolet light, and infrared light to an observation target; and an X-ray irradiation unit that irradiates X-rays to another observation target. When the light from the light irradiating means irradiates the observation object, a projection image of the observation object is formed, and when the X-ray from the X-ray irradiating means irradiates another observation object, another observation is performed. A scintillator film on which a fluorescent image of the object is formed, a transparent member including one surface and the other surface, and supporting the scintillator film by disposing the scintillator film on one surface; and a transparent member. And an imaging unit that captures a projected image and a fluorescence image appearing on the other surface of the imaging device, and an observation device that uses light and X-rays.

According to the above configuration, the projected image of the observation target when the scintillator film is irradiated with light (at least one of visible light, ultraviolet light, and infrared light), and the projected image of the observation object when X-rays are irradiated on the scintillator film. Since a fluorescent image of the object to be observed is formed, these images can be observed using a single imaging unit, and an imaging element that does not have an X-ray imaging function is used as the imaging unit. Can be.

The exposure method of the present invention is an exposure method for exposing a resist formed on a substrate to be a circuit substrate using a mask substrate, wherein the projection image of the alignment mark of the mask substrate and the fluorescent image of the alignment mark of the substrate are provided. Forming a projected image on the scintillator film by irradiating the mask substrate with at least one of visible light, ultraviolet light, and infrared light, and forming a fluorescent image on the scintillator film. Is irradiated on the substrate on which the resist is formed, thereby forming an image on the scintillator film, and further, an image capturing step for capturing a projected image and a fluorescent image, and an image capturing step for aligning the mask substrate and the substrate. A moving step of moving at least one of the mask substrate and the substrate based on the projection image and the fluorescent image captured in the step, and after the moving step Irradiating the resist with light for exposure through a mask substrate. According to the above configuration, a projection image of the alignment mark on the mask substrate formed on the scintillator film by being irradiated with light (at least one of visible light, ultraviolet light, and infrared light); By irradiating the line, a fluorescent image of the alignment mark of the substrate formed on the scintillator film is formed, so that these images can be observed using one image pickup device, and can be used as an image pickup device. An imaging device having no X-ray imaging function can be applied.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a diagram showing a configuration of the observation device of the present embodiment.

FIG. 2 is a diagram showing a configuration of the exposure apparatus of the present embodiment.

FIG. 3 is a flowchart illustrating the exposure method according to the present embodiment.

FIG. 4 is an enlarged view of a part of a monitor provided in the observation device of the present embodiment, in which an image of the alignment mark on the mask substrate is displayed.

FIG. 5 is an enlarged view of a part of a monitor provided in the observation device of the present embodiment, in which an image of an alignment mark of a substrate serving as a circuit substrate is displayed.

FIG. 6 shows a part of a monitor provided in the observation apparatus of the present embodiment, in which a state in which the image of the alignment mark of the mask substrate and the image of the alignment mark of the substrate to be a circuit board are overlapped is displayed. FIG.

FIG. 7 is a diagram showing a configuration of a modification of the observation device of the present embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION

A preferred embodiment of the present invention will be described with reference to the drawings.

[Configuration of observation device]

First, the configuration of the observation device of the present embodiment will be described with reference to FIG. FIG. 1 is a configuration diagram showing an outline of the observation device 1 of the present embodiment. The observation device 1 includes a CCD camera 6 which is an example of an imaging unit, an X-ray tube 5 which is an example of an X-ray irradiation unit and generates X-rays 5a, and a visible light 21a which is an example of a light irradiation unit. And a light emitting diode 21 that is generated. Connecting these positions with a line to form a triangle, The CCD camera 6, the X-ray tube 5, and the light emitting diode 21 are arranged. The X-ray tube 5 includes an X-ray exit 5b from which the X-ray 5a is emitted, and the X-ray exit 5b faces the lens of the CCD camera 6.

The observation device 1 is further electrically connected to the X-ray tube 5, and is electrically connected to the controller 7 for adjusting the voltage, current, etc. of the X-ray tube 5, and to the light emitting diode 21, which emits light. A power supply 23 for controlling light emission of the diode 21. In the present embodiment, for example, a laser or a discharge tube (for example, a halogen lamp or a metal halide lamp) can be used instead of the light emitting diode 21. In addition to ultraviolet rays, ultraviolet rays and infrared rays can also be used. In this case, the light irradiation means is an ultraviolet ray generator or an infrared ray generator. In addition, it is preferable to dispose a lens 24 for converting visible light 21 a into parallel light in an optical path between the light emitting diode 21 and the visible light reflecting mirror 25. As a result, the scattering (diffusion) of visible light 2 la can be reduced, and blurring of the image can be prevented.

The observation device 1 further includes a stage 11 at a position facing the X-ray tube 5 via a visible light reflecting mirror 25 described later. The stage 11 supports a mask substrate 17 and a substrate 15 including an observation target.

The observation device 1 further includes a scintillator film 19 disposed between the stage 11 and the CCD camera 6. The scintillator film 19 is formed by adjusting the thickness to allow transmission of visible light. When the mask substrate 17 is irradiated with the visible light 21 a, the scintillator film 19 has a mask substrate 17. A projection image such as an alignment mark is formed. This alignment mark is an example of an observation target. The mask substrate 17 is composed of a glass substrate and an opaque film formed on the glass substrate and having the same pattern as the wiring pattern of the circuit board. In addition, when the substrate 15 (the substrate 15 does not transmit light) serving as the core substrate of the circuit substrate is irradiated with the X-rays 5a, the scintillator film 19 has an alignment mark on the substrate 15 or the like. A fluorescent image is created by visualizing the X-ray fluoroscopic image. This alignment mark is an example of another object to be observed. Even if it is formed in a place where it cannot be seen, it becomes possible to take an image with x-rays. The scintillator layer 1 9, G d _₂ 0 ₂ S: a T b type. The thickness of the scintillator film 19 is, for example, 100 zm or less. If the thickness of the scintillator film 19 is larger than this, a projected image is less likely to be formed on the scintillator film 19. For example, when the X-ray energy is 60 to 80 KV, the thickness of the scintillator film 19 is 50 μιη.

If the X-ray intensity is increased, the thickness of the scintillator film 19 can be further reduced, and the scintillator film 19 can be reduced to a single particle layer.

The observation device 1 further includes a visible light reflection mirror 25 disposed between the X-ray tube 5 and the scintillator film 19. The visible light reflecting mirror 25 is an example of a reflecting means, and reflects the visible light 21 a generated by the light emitting diode 21 toward the mask substrate 17. Since the observation device 1 includes the visible light reflecting mirror 25, the mask substrate 17 can be irradiated with the visible light 21a from the light emitting diode 21 without moving the X-ray tube 5. Since the X-rays 5a pass through the visible light reflecting mirror 25 and irradiate the substrate 15, the X-rays 5a may be attenuated by the visible light reflecting mirror 25. In order to suppress this attenuation, the visible light reflecting mirror 25 is preferably formed by depositing a reflective film on a glass substrate having a thickness of 200 / zm or less, or by depositing a reflective film on a carbon substrate. The glass substrate is preferably made of synthetic quartz glass.

The observation device 1 further includes a fiber optic plate (Fiber Optic Plate) 27 on which the scintillator film 19 is arranged. The fiber optic plate 27 is an example of a transparent member, and has one surface 27a and the other surface 27b. The fiber boutique plate 27 has a tapered shape composed of a cylindrical portion including one surface 27a, and a cylindrical portion including the other surface 27b and tapering toward the other surface 27b. Have. On one surface 27a, a scintillator film 19 is formed. Since the scintillator film 19 is thin, the scintillator film 19 is reinforced by the fiber optic plate 27. The fluorescence image and projection image formed on the scintillator film 19 by the fiber boutique plate 27 Transferred from 27a to the other side 27b. The CCD camera 6 is optically connected to the fiber boutique plate 27 on the other surface 27. The fiber obtic plate 27 need not have a tapered shape (for example, a cylindrical shape).

The observation device 1 further includes a driver circuit unit 31 including an operation unit for performing an operation for processing an image captured by the CCD camera 6, a storage unit for storing image data, and a driver circuit unit 31. A monitor 33 that is electrically connected and displays an image picked up by the CCD camera 6. A personal computer may be used instead of the monitor 33. Further, instead of the CCD camera 6, a solid-state imaging device (for example, a MOS image sensor), a vidicon camera, an imaging tube (for example, an image intensity), or the like can be used. The above is the outline of the configuration of the observation device 1.

[Configuration of exposure apparatus]

Next, the configuration of the exposure apparatus of the present embodiment will be described. FIG. 2 is a configuration diagram showing an outline of the exposure apparatus 4 of the present embodiment. The exposure device 4 includes the observation device 1 shown in FIG. 1, and further includes a mercury lamp 3 which is an example of exposure light irradiation means for generating light 3a for exposure. The mercury lamp 3 is located farther away from the X-ray tube 5 than the CCD camera 6 is. Between the mercury lamp 3 and the stage 11, a module including a CCD camera 6, a scintillator film 19, a fiber optic plate 27 and the like is arranged. At the time of exposure, this module is moved to a position where it does not hinder exposure by a moving means (not shown).

The exposure apparatus 4 further includes a stage 11 disposed between the scintillator film 19 and the visible light reflecting mirror 25, and a stage drive unit 13 for moving the stage 11. In FIG. 2, a mask substrate 17 is mounted on a stage 11, and a substrate 15 is mounted thereon. The above is the outline of the configuration of the exposure apparatus 4.

[Operation of observation device and exposure device] Next, the operation of the exposure apparatus 4 will be described with reference to FIGS. FIG. 3 is a flowchart illustrating the operation of the exposure apparatus 4. First, the mask substrate 17 is transferred onto the stage 11 by a transfer mechanism (not shown). Then, visible light 21 a is generated from the light emitting diode 21 (step S 1). The visible light 21 a is reflected by the visible light reflecting mirror 25 and irradiates the mask substrate 17. As a result, a projected image such as an alignment mark of the mask substrate 17 is formed on the scintillator film 19. This projected image passes through the scintillator film 19, is transferred from one surface 27 a of the fiber optic plate 27 to the other surface 27 b, is captured by the CCD camera 6, and is displayed on the monitor 33. Is done. FIG. 4 is an enlarged view of a part of the monitor 33 in this state. On the monitor 33, an image of the alignment mark 17a of the mask substrate 17 is displayed. Then, the arithmetic unit of the driver circuit unit 31 calculates the position of the center of gravity of the mark 17a, and stores the position of the center of gravity in the storage unit of the driver circuit unit 31 (step S2). This position of the center of gravity serves as a reference for positioning. Note that the positioning reference may be an arbitrary minute point in the mark 17a. In this case, the position of the minute point is calculated and stored.

Next, the substrate 15 is moved by a transport mechanism (not shown) and transported to a position overlapping the mask substrate 17 as shown in FIG. Then, an X-ray 5a is generated from the X-ray tube 5 (step S3). The X-rays 5 a pass through the visible light reflecting mirror 25 and irradiate the substrate 15. Thus, an X-ray fluoroscopic image such as an alignment mark on the substrate 15 is incident on the scintillator film 19 to form a visualized fluorescent image. This fluorescent image is transferred from one surface 27a of the fiber optic plate 27 to the other surface 27b, captured by the CCD camera 6, and displayed on the monitor 33. FIG. 5 is an enlarged view of a part of the monitor 33 in this state. On the monitor 33, an image of the alignment mark 15a of the substrate 15 is displayed. Then, the arithmetic unit of the driver circuit unit 31 calculates the position of the center of gravity of the mark 15a, and stores the position of the center of gravity in the storage unit of the driver circuit unit 31 (step S4). This position of the center of gravity is Become. Note that the positioning reference may be an arbitrary minute point in the mark 15a. In this case, the position of the minute point is calculated and stored.

Next, the arithmetic unit of the driver circuit 31 calculates the distance between the position of the center of gravity of the mark 15a and the position of the center of gravity of the mark 17a (step S5). Then, the stage 11 is moved by the stage drive unit 13 so that the mask substrate 17 is moved by the above-mentioned distance, and the center of gravity of the mark 17a is adjusted to the center of gravity of the mark 15a. FIG. 6 is an enlarged view of a part of the monitor 33 in this state. The monitor 33 displays a state in which the image of the mask substrate alignment mark 17a and the image of the substrate alignment mark 15a overlap each other. Thus, the alignment between the substrate 15 and the mask substrate 17 is completed (step S6). Note that the mask substrate 17 may be fixed and the substrate 15 may be moved to perform the alignment, or the mask substrate 17 and the substrate 15 may be moved to perform the alignment.

Then, by generating light 3a from the mercury lamp 3, the resist formed on the substrate 15 is selectively exposed through the mask substrate 17 (step S7).

[Main effects of the present embodiment]

The main effects of the present embodiment will be described. According to the present embodiment, the scintillator film 19 is formed with a fluorescent image (for example, an alignment mark) of the substrate 15 irradiated with X-rays, and a mask substrate 17 irradiated with visible light. A projected image (eg, alignment mark) is formed. Therefore, it is not necessary to newly provide a screen for forming a projected image of the mask substrate 17.

Further, since a fluorescent image and a projected image are formed on the scintillator film 19, these images can be imaged by one imaging means (CCD camera 6). Therefore, it is not necessary to arrange two imaging means for X-rays and visible light, so that the size of the observation device 1 and the exposure device 4 can be reduced.

Further, since a fluorescent image and a projected image are formed on the scintillator film 19, the imaging means (C

The CD camera 6) needs only the function of capturing images with visible light, and captures images with X-rays. No function is required.

According to the present embodiment, the scintillator film 19 is formed on one surface 27 a of the fiber optic plate 27, and the other surface 27 b is optically connected to the CCD camera 6. I have. For this reason, the CCD camera 23 can capture a projected image or a fluorescent image in a clear state.

The application of the present embodiment is not limited to the observation of the alignment mark as described above. For example, a defect inspection of a mask substrate can be performed by a projected image, and a defect inspection of a substrate to be a circuit substrate can be performed by a fluorescent image.

[Modification of this embodiment]

FIG. 7 is a diagram showing a configuration of a modification of the observation device of the present embodiment. The same components as those of the observation device 1 shown in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted.

The observation device 2 according to the modification does not include the fiber optic plate 27 of the observation device 1, and the transparent glass substrate 35 is disposed at that position. The transparent glass substrate 35 has a cylindrical shape including one surface 35a and the other surface 35b. A scintillator film 19 is formed on one surface 35a. The transparent glass substrate 35 is an example of a transparent member. The transparent glass substrate 35 is a normal glass and does not include an optical fiber. Note that, instead of the transparent glass substrate 35, for example, a transparent body such as plastic may be used.

An optical lens 37 is arranged on the optical path between the other surface 35 b of the transparent glass substrate 35 and the CCD camera 6. The projection image and the fluorescence image transmitted through the other surface 35b are converged by the optical lens 37 and captured by the CCD camera 6. Since the transparent glass substrate 35 does not have a transfer function unlike the fiber optic plate 27, the transparent glass substrate 35 and the CCD camera 6 are optically coupled by the optical lens 37.

The observation device 2 according to the modified example includes the visible light reflecting mirror 25 of the observation device 1. I have not. For this reason, the position of the light emitting diode 21 (including the lens 24) and the position of the X-ray tube 5 are changed by a switching unit (not shown) so that the visible light generated from the light emitting diode 21 is irradiated on the mask substrate 17. Can be switched. The observation device 2 according to the modification can also be applied to an exposure device.

Industrial applicability

INDUSTRIAL APPLICABILITY The present invention is applicable to lithography and the like in a semiconductor device manufacturing process.

Claims

The scope of the claims

1. Light irradiating means for irradiating at least one of visible light, ultraviolet light, and infrared light to the observation object;

X-ray irradiating means for irradiating X-rays to another observation object,

When the light of the light irradiating unit is irradiated on the observation target, a projected image of the observation target is formed, and when the X-rays of the X-ray irradiating unit are irradiated on the other observation target, A scintillator film on which a fluorescent image of the other observation object is formed; and a scintillator film including one surface and the other surface, wherein the scintillator film is disposed on the one surface. A transparent member supporting the

An imaging means for imaging the projected image and the fluorescent image appearing on the other surface of the transparent member;

An observation device using light and X-rays, comprising:

2. The observation device using light and X-rays according to claim 1, wherein the thickness of the scintillator film is 100 m or less.

3. The observation device using light and X-rays according to claim 1, wherein the transparent member includes a bundle of fibers.

4. The observation device using light and X-rays according to any one of claims 1 to 3, further comprising a reflection unit configured to reflect light of the light irradiation unit toward the observation target.

5. The observation device using light and X-rays according to claim 4, wherein the reflection means is formed by forming a reflection film on a glass substrate.

6. An exposure apparatus for exposing a resist formed on a substrate to be a circuit substrate using a mask substrate,

Light irradiating means for irradiating the mask substrate with at least one of visible light, ultraviolet light, and infrared light;

X-ray irradiating means for irradiating the substrate on which the resist is formed with X-rays; and when the mask substrate is irradiated with light from the light irradiating means, A scintillator film, wherein a projected image of the alignment mark is formed, and a fluorescent image of the alignment mark on the substrate is formed when the substrate is irradiated with X-rays of the X-ray irradiating means;

A transparent member including one surface and the other surface, and supporting the scintillator film by disposing the scintillator film on the one surface;

In order to align the mask substrate and the substrate, at least one of the mask substrate and the substrate is determined based on the projection image and the fluorescent image captured by the imaging unit. Moving means for moving;

Exposure light irradiation means for irradiating the resist with light for exposure through the mask substrate,

An exposure apparatus comprising:

7. An exposure method for exposing a resist formed on a substrate to be a circuit substrate using a mask substrate,

Forming a projected image of the alignment mark on the mask substrate and a fluorescent image of the alignment mark on the substrate on a scintillator film,

The projected image is formed on the scintillator film by irradiating the mask substrate with at least one of visible light, ultraviolet light, and infrared light, and the resist is formed on the fluorescent image by X-rays. By irradiating the substrate, the scintillator film is formed,

Furthermore,

An imaging step of capturing the projected image and the fluorescent image,

In order to align the mask substrate and the substrate, at least one of the mask substrate and the substrate is determined based on the projection image and the fluorescent image captured in the imaging step. A moving step to move; Irradiating the resist with light for exposure through the mask substrate after the moving step;

An exposure method comprising:

8. X-ray irradiation means for irradiating X-rays,

A stage provided to face the X-ray irradiator, and supporting the observation target; and irradiating the observation target supported by the stage with light containing at least one of visible light, ultraviolet light, and infrared light. Light irradiating means,

A scintillator film that is provided at a position facing the X-ray irradiating means via the stage, transmits the light, and emits fluorescence in response to the incidence of the X-ray; and the light that has passed through the scintillator film and Imaging means for detecting the fluorescence emitted by the scintillator and

An observation device, characterized in that: