JP2001007012A - Aligner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable an aligner to make the boundary section of a irradiating region of light clear, without lowering the throughput of the aligner, increasing its weight, significantly increasing its cost, or increasing the occupying space required by the aligner. SOLUTION: A light L2 made incident to a light guiding rod 90 at a maximum incident angle θmax reaches the bottom face 94 and inclined surfaces 94 and 95 of the rod 90, and the light reaching the bottom face 93 is emitted from the bottom face 93 as a light which is parallel to the incident light L1. From the inclined surfaces 94 and 95, the light is emitted as refracted light rays. The inclinations and sizes of the inclined surfaces 94 and 95 are set, so that the light rays L3, L4, and L5 respectively emitted form end sections 93a, 94a, and 95 of the bottom face 93 and inclined surfaces 94 and 95 reach the position P3 of the end section of the region to be exposed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for exposing a semiconductor substrate, a glass substrate for a photomask, a substrate for an optical disk or the like (hereinafter simply referred to as "substrate") to light by exposing the region to be exposed to light. The present invention relates to an exposure apparatus.

[0002]

2. Description of the Related Art Generally, for a substrate as described above,
A series of substrate processes is achieved by sequentially performing a resist coating process, a developing process, and a heat treatment associated therewith. Among these, the resist coating process is a process in which a photoresist (hereinafter, simply referred to as “resist”) is supplied while rotating the substrate, and the resist is applied to the entire surface of the substrate by centrifugal force.

[0003] A resist film is formed on the entire surface of the substrate coated with the resist as described above. However, since the resist film formed on the edge of the substrate causes dust due to mechanical contact during the transfer of the substrate, it is necessary to remove the resist film formed on the edge. Since a pattern such as a semiconductor chip is not formed at the edge of the substrate, the resist film formed at the edge may be removed. In addition, the resist film may be removed from a region where a pattern is not formed even in a region other than the edge portion of the substrate.

For this reason, conventionally, light (generally, ultraviolet light) from a light source has been guided to an unnecessary resist film, and the resist film has been exposed and removed. The following two methods are mainly used as a method for conducting light exposure by guiding light from a light source to a resist film on a substrate.

First, a first method is a method in which light emitted from a light source is guided to a resist film by a quadrangular prism-shaped light guide rod made of quartz. Light that has entered from the incident surface of the light guide rod is mixed by repeating total reflection inside the light guide rod, and then exits from the exit surface opposite to the entrance surface. Then, by irradiating the light guide rod with the light exit surface brought close to the resist film on the substrate to about 1 mm, the resist film in a region substantially equivalent to the light exit surface of the light guide rod is exposed.

[0006] As a second method, after light emitted from a light source is guided by a light guide rod similar to the above,
Further, it is a method in which an image is formed on a resist film using an image forming optical system such as a lens. That is, the light emitted from the emission surface of the light guide rod is imaged by the imaging lens on the area to be exposed.

[0007]

However, in the case where the above-mentioned conventional method is used, the following problems occur regardless of which method is used. First, in the case of the first method using only the light guide rod, the light use efficiency is high, the cost is low, the weight is small, and the space occupied is small. However, the boundary of the exposure area (light irradiation area) is unclear. Problem. That is, on the precision of the components of the apparatus, it is necessary to provide a certain interval so that the emission surface of the light guide rod and the substrate do not come into contact with each other due to the rotation operation of the substrate. As the distance from the substrate increases, the boundary of the irradiation area on the resist film becomes blurred. This will be described with reference to FIG.

FIG. 12 is a diagram for explaining light irradiation from a conventional light guide rod. Light is incident on the light guide rod 2 from an incident surface (not shown), and the light is transmitted from the exit surface 2a to the substrate W.
The light is emitted toward the upper resist film 1. The maximum incident angle of the light incident on the light guide rod 2 is a value that depends on the light collecting characteristics of the light source. Since the incidence surface and the emission surface 2a of the light guide rod 2 are parallel, the maximum emission angle of the light emitted from the emission surface 2a is the same as the maximum incidence angle.

As shown in FIG. 12, the position P12 at which the light L12 emitted from the end of the emission surface 2a of the light guide rod 2 at a maximum emission angle of 23 ° reaches the resist film 1 is determined by the position of the light guide rod 2. It is the outer edge of the irradiation area. The light that can reach the outer edge of the irradiation area is only light emitted from the end of the emission surface 2a at the maximum emission angle of 23 °.

On the other hand, in the irradiation area on the right side of the drawing from the position P12, light emitted from a predetermined area of the emission surface 2a of the light guide rod 2 is superimposed.
In particular, in the irradiation area on the right side of the position P13 where the light L13 emitted from the end of the emission surface 2a at the maximum emission angle of 23 ° reaches the resist film 1, the maximum amount of light is uniformly superimposed. Will be. Accordingly, in the region from the position P12 to the position P13 in the irradiation region of the light guide rod 2, the light intensity gradually increases.

FIG. 13 is a diagram showing an intensity distribution of light emitted from a conventional light guide rod. The abscissa in the figure indicates a position on the surface to be irradiated (here, a position on the resist film 1), and 0 μm is directly below the end of the exit surface 2a in the vertical direction. The vertical axis indicates the relative intensity of the irradiated light, and the intensity of the irradiation area on the right side in FIG. 12 with respect to the position P13 is set to “1”. FIG. 13 shows the intensity distribution when the maximum incident angle on the light guide rod 2 is 23 ° and the distance between the emission surface 2a of the light guide rod 2 and the substrate W (strictly, the resist film 1) is 1 mm. It is.

As shown in FIG. 13, in the region from the position P12, which is the outer edge of the irradiation region of the light guide rod 2, to the position P13, the light intensity gradually rises, and the irradiation on the right side in FIG. It is stable at the highest strength in the region. Such a gentle increase in light intensity from the position P12 to the position P13 indicates that the boundary portion of the irradiation area of the light guide rod 2 is blurred.

Here, for example, assuming that the positive resist is completely exposed and removed in a region having a relative intensity of 0.3 or more in FIG. In the region of about 250 μm up to P14, the resist remains with a gentle slope. In other words, in the first method using only the light guide rod, the boundary portion of the exposure region is unclear, so that a tapered resist is formed at the boundary between the portion where the resist is to be left and the portion to be removed. This causes a problem of remaining. Such a residual resist causes particles and the like in a later step.

On the other hand, in the case of the second system using the light guide rod and the image forming lens, the image forming performance of light is improved by incorporating the image forming lens, so that the boundary portion of the exposure area becomes clear. Therefore, although the problem of the residual resist as in the first method described above does not occur, since an imaging optical system such as a lens and their holders must be provided,
The cost is higher than that of the first method, and the arrangement space of the optical system is increased, so that the size of the apparatus is increased and the weight is increased. The increase in the weight of the optical system lowers the moving speed, thereby lowering the throughput, and also necessitates strengthening the drive mechanism of the optical system, which leads to a further increase in cost.

In the second method, the numerical aperture (NA) of the lens needs to be as large as about 0.4 in order to form an image of all the light emitted from the light guide rod by the lens. However, designing a lens with such a large numerical aperture is very difficult. In order to provide a certain level of imaging performance, the numerical aperture (NA) needs to be about 0.25. In such a lens, only about 40% of the light from the light guide rod is used effectively. Can not. Furthermore, light loss also occurs due to surface reflection or absorption of the lens. Therefore, the second method has a problem that the utilization efficiency of light from the light source is low, and the exposure time is accordingly long. This leads to a decrease in the throughput of the device.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and does not cause a decrease in throughput, weight, a significant increase in cost, and an increase in required space.
An object of the present invention is to provide an exposure apparatus capable of sharpening a boundary portion of a light irradiation region.

[0017]

In order to solve the above-mentioned problems, the present invention is directed to an exposure apparatus that irradiates an exposure target area on a substrate to be exposed with light to expose the exposure target area. A light source for irradiating the light; and a column-shaped light guide for guiding the light from the light source toward the exposure target area on the substrate and emitting the light from an emission surface facing the exposure target area. And a bent portion that bends light passing through the light guide rod toward the exposure target area at least at a part of the periphery of the light exit surface of the light guide rod.

According to a second aspect of the present invention, in the exposure apparatus according to the first aspect of the present invention, the bending portion for refracting the light emitted from the peripheral portion of the emission surface toward the region to be exposed, at the bending portion. And

According to a third aspect of the present invention, in the exposure apparatus according to the second aspect of the present invention, the refracting portion includes an inclined surface that forms an obtuse angle with both the bottom surface and the side surface of the light guide rod.

According to a fourth aspect of the present invention, in the exposure apparatus according to the third aspect of the present invention, the refracting portion includes a multi-step inclined surface in which the inclined surface is formed in multiple steps.

According to a fifth aspect of the present invention, in the exposure apparatus according to the fourth aspect of the present invention, the light incident on the light guide rod at a maximum incident angle from the light source, wherein Light emitted from the end of the bottom surface forming the boundary with the inclined surface and light emitted from the side end of each inclined surface constituting the multi-step inclined surface reach the end of the exposure target region. Thus, the multi-step inclined surface is formed.

According to a sixth aspect of the present invention, in the exposure apparatus according to any one of the third to fifth aspects, an antireflection film for preventing light reflection is formed on at least the inclined surface.

According to a seventh aspect of the present invention, in the exposure apparatus according to any one of the first to sixth aspects, the exposure target region is an edge of the substrate, and the bent portion is the light guide. It is provided at a portion of the peripheral portion of the emission surface of the rod that faces the center side of the substrate.

[0024] In this specification, the "exposure target area" means an area which needs to be exposed by light irradiation and is a target of irradiation. In this specification, “bending” is a concept term including both refraction and diffraction.

[0025]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a perspective view showing an example of an exposure apparatus according to the present invention. FIG. 1 is provided with an XYZ orthogonal coordinate system in which a horizontal plane is an XY plane and a vertical direction is a Z-axis direction. Hereinafter, a mechanical configuration of the exposure apparatus will be described with reference to FIG.

This exposure apparatus is an apparatus suitable for exposing an edge portion of a substrate having a photosensitive resin film and, in particular, a chemically amplified resist film formed on the surface thereof.
It includes a substrate rotating unit 20, a Y-axis driving unit 30, an X-axis driving unit 40, an exposure unit 50, an X-axis sensor 60, a Y-axis sensor 70, an edge sensor 80, and a control unit 85.

The substrate rotation unit 20 suction-holds the substrate W by a suction chuck 21 in a substantially horizontal posture, and the substrate rotation motor 2
By driving the substrate 2, the substrate W is rotated at a desired angle with the vertical direction as a rotation axis.

The Y-axis drive section 30 is a drive mechanism for driving the exposure section 50 to translate in the Y-axis direction. The Y-axis drive unit 30
A Y-axis motor 31 fixed to the base 10, a Y-axis ball screw 32 connected to the rotation shaft thereof, and a Y-axis linear guide 3
3 and a Y-axis base 34 slidably attached thereto and driven to translate by a Y-axis ball screw 32.

The X-axis drive section 40 is a drive mechanism for driving the exposure section 50 to translate in the X-axis direction. The X-axis drive unit 40
The X-axis linear guide 41 provided on the Y-axis base 34 of the Y-axis drive unit 30 along the X-axis direction, the X-axis motor 42 and the rotation axis of the X-axis motor 42 are hung along the X-axis direction. This is a drive mechanism in the X-axis direction including a timing belt 43 provided.

The exposure unit 50 includes an exposure base 51 slidably mounted on the X-axis linear guide 41 of the X-axis drive unit 40.
A driving force transmitting member 52 connected to the timing belt 43 and transmitting the driving force to the exposure base 51; and an exposure head 53 provided on the exposure base 51, and irradiates light onto the substrate W to mainly emit light. The edge of the substrate W is exposed. The structure of the exposure head 53 will be further described later.

The X-axis sensor 60 is a photosensor provided on the Y-axis base 34 with the light-emitting element and the light-receiving element facing each other, and detects the position of the exposure unit 50 in the X-axis direction. A projection (not shown) provided at the lower end of the exposure base 51 of the exposure unit 50 can pass through the gap between the light emitting element and the light receiving element, and by detecting the passing state, the exposure unit 50 (strictly speaking, the exposure base 51) is detected. Is detected in the X-axis direction.

The Y-axis sensor 70 is a photo sensor similar to the X-axis sensor 60 provided on the base 10, and detects the position of the exposure unit 50 in the Y-axis direction. The Y-axis sensor 70 detects the position of the exposure unit 50 (strictly speaking, the Y-axis base 34) in the Y-axis direction by detecting a protrusion provided on the lower surface of the Y-axis base 34.

The edge sensor 80 is a photo sensor similar to the X-axis sensor 60 and the Y-axis sensor 70. The edge sensor 80 receives light from the light-emitting element so as to sandwich the substrate W held on the suction chuck 21 of the substrate rotating unit 20 from above and below. And an element for detecting the orientation flat or notch of the substrate W and detecting the amount of eccentricity of the substrate W with respect to the vertical rotation axis of the substrate rotation unit 20.

Each of the above-mentioned parts and each of the sensors is a CP.
U and a control unit 85 having a memory.
The control unit 85 transmits a signal to the Y-axis drive unit 30 and the X-axis drive unit 40 based on the detection result from each sensor, adjusts the position of the exposure unit 50, and controls the operation timing of the exposure unit 50. Thus, the exposure of the substrate W is performed.

Next, the exposure section 50 of the exposure apparatus will be described in more detail with reference to FIG. Exposure unit 50
The exposure head 53 includes a xenon flash lamp 54, a light guide rod 90, and a dichroic mirror 55.

The xenon flash lamp 54 is a flash lamp having a small bulb 54a filled with xenon gas and having an elliptical mirror 54b, an electrode 54c, and a trigger probe (not shown). The xenon flash lamp 54 is supplied with power from a power source (not shown).
Pulse emission can be performed over a wide range of wavelengths from the ultraviolet region to the infrared region. Especially, the sensitivity of the chemically amplified resist is good, and the light emission efficiency of light having a wavelength of 200 nm to 300 nm is good. Suitable for use as a light source for lighting. Further, the xenon flash lamp 54 is electrically connected to the control unit 85, and the control unit 85 can control a light emission period, a start timing thereof, and a light emission pulse cycle.

The light emitted from the xenon flash lamp 54 is reflected and condensed by the elliptical mirror 54b, further reflected by the dichroic mirror 55, and guided to the light guide rod 90. Here, the dichroic mirror 55 is substantially in the ultraviolet wavelength range, that is, the wavelength is about 200 nm.
It has the property of reflecting only light in the region of ~ 300 nm and transmitting light of other wavelengths, whereby light of wavelengths unnecessary for ultraviolet light exposure passes through the dichroic mirror and does not reach the exposed surface of the substrate . Therefore, expansion of the substrate W due to heat and unevenness of the resist reaction can be prevented.

FIG. 3 is a partial perspective view of the light guide rod 90. The light guide rod 90 is a pillar-shaped (in the present embodiment, substantially quadrangular prism-shaped) light guide rod made of quartz, and the entire outer surface thereof is optically polished. Returning to FIG. 2, light emitted from the xenon flash lamp 54 is condensed by the elliptical mirror 54b, selectively reflected by the dichroic mirror 55, and then incident on the incident surface 91 which is one end surface of the light guide rod 90. The total reflection is repeated by each side surface 97 in the inside. As a result, the light incident from the incident surface 91 is mixed inside the light guide rod 90 and is emitted again from the exit surface 92 which is the other end surface. Here, since the outer surfaces of the light guide rod 90 are optically polished, a loss due to scattering at the time of reflection on those surfaces hardly occurs.

Further, as shown in FIG.
The light exit surface 92 has a bottom surface 93 and a two-step inclined surface 96, and one side of the rectangular exit surface 92 has a two-step inclined surface 96.
Is provided. Furthermore, the two-step inclined surface 96
It is composed of two inclined surfaces 94 and 95. Each of the bottom surface 93 and the two inclined surfaces 94 and 95 is a polished smooth plane. An antireflection film formed of a dielectric multilayer film is deposited on the two-step inclined surface 96. The contents of the two-step inclined surface 96 and the antireflection film will be further described later.

Next, the procedure of the exposure processing in the exposure apparatus having the above configuration will be briefly described. First, the substrate W carried in from the outside of the apparatus is suction-held by the suction chuck 21 in a substantially horizontal posture. Next, the control unit 85 transmits a signal to the Y-axis drive unit 30 and the X-axis drive unit 40 while referring to the detection results from the X-axis sensor 60 and the Y-axis sensor 70, and moves the exposure unit 50 to a predetermined exposure position. (In the present embodiment, it is moved to the edge of the substrate W). Thereafter, the exposure processing is advanced by the substrate rotation motor 22 rotating the substrate W at a predetermined speed while repeating the pulse emission from the xenon flash lamp 54. Since the exposure unit 50 is located at the edge of the substrate W and emits light repeatedly, and the substrate rotation motor 22 rotates the substrate W at a predetermined speed, the substrate W
Is exposed over the entire outer circumference of the substrate W, whereby the edge exposure of the substrate W is performed.

Here, the “exposure target area” in this specification will be described. FIG. 4 is a diagram illustrating an exposure target area. The exposure apparatus according to the present invention is an apparatus for exposing and removing an unnecessary resist film formed on the substrate W. The unnecessary resist film is, in short, a portion of the resist film where pattern formation is not performed. In the exposure apparatus according to the present invention, only the unnecessary resist film in which such pattern formation is not performed should be performed by irradiating light, and the `` exposure target area '' in this specification is Such a region to be exposed (a region where light irradiation is desired) is meant. For example, when the edge portion exposure of the substrate W is performed as in the present embodiment, the annular area EA1 in FIG. 4 is the exposure target area.

In the exposure apparatus of this embodiment, as described above, a two-step inclined surface 96 is formed on a part of the light guide rod 90 (see FIG. 3). The behavior of light when the light from the xenon flash lamp 54 is incident on the light guide rod 90 having such an inclined surface and emitted toward the substrate W will be described below.

FIG. 5 is a diagram for explaining the behavior of the light emitted from the emission surface 92 of the light guide rod 90. In addition,
In the figure, a resist film 1 is formed on a substrate W, the left side in the figure is the center side of the substrate W, and the right side in the figure is the edge side of the substrate W. And in this embodiment,
It is assumed that the resist film 1 on the right side of the drawing from the position P3 is an unnecessary resist film to be removed. Therefore, in FIG. 5, the region on the substrate W on the right side in the figure with respect to the position P3 is the exposure target region where the exposure of the resist film 1 is to be performed by light irradiation, and the position P3 is the end of the exposure target region (FIG. (The inner peripheral portion of the area EA1).

The light emitted from the xenon flash lamp 54 is reflected and condensed by the elliptical mirror 54b, is reflected by the dichroic mirror 55, and is incident on the incident surface 91 of the light guide rod 90. The maximum incident angle θmax of the incident light at this time is a value determined by the light-collecting characteristics of the elliptical mirror 54b. Light guide rod 90 at maximum incident angle θmax
The incident light L1 incident on the inside is refracted on the incident surface 91 and travels through the light guide rod 90 as light L2. The refraction angle θ ′ _{1 at} this time is a value that satisfies Equation 1 below.

[0046]

(Equation 1)

Here, “n” is the refractive index of the light guide rod 90. The light L2 traveling in the light guide rod 90 is incident on the bottom surface 93 at an incident angle θ ′ ₁ because the light L2 travels in a uniform medium although the total reflection is repeated by the side surface 97 of the light guide rod 90. The side surface 97 is a surface parallel to the longitudinal direction of the light guide rod 90 having a substantially quadrangular prism shape, and the incident surface 91 and the bottom surface 93 are surfaces perpendicular to the longitudinal direction of the light guide rod 90. Then, the light L2 incident on the bottom surface 93 is
The light is refracted at the bottom surface 93 and becomes the outgoing light L3. The outgoing angle θ ″ ₁ of the outgoing light L3 is a value that satisfies Equation 2 below.

[0048]

(Equation 2)

As is apparent from the equations (1) and (2), the output angle θ ″ ₁ of the output light L3 from the bottom surface 93 is equal to the maximum incident angle θmax of the incident light L1.
3 is a plane parallel to each other, the maximum incident angle θmax
The outgoing light L3 travels at the same outgoing angle θ ″ ₁ .

Here, the outgoing light L3 emitted from the end 93a of the bottom surface 93 (the end on the center side of the substrate W), which forms the boundary between the bottom surface 93 and the inclined surface 94, is on the substrate W (strictly speaking, the substrate W). W
(Position on the resist film 1) formed at the position P3.
As described above, the position P3 is the end of the exposure target area, and the emitted light L3 emitted from the end 93a of the bottom surface 93 reaches the end of the exposure target area. Conversely, the position of the exposure unit 50 is adjusted so that the emitted light L3 emitted from the end 93a of the bottom surface 93 reaches the end of the exposure target area.

On the other hand, the light L 2 traveling in the light guide rod 90
Naturally reaches not only the bottom surface 93 but also the inclined surfaces 94 and 95. The light L2 is incident on the inclined surface 94 at an incident angle θ ′ ₂ . Assuming that the angle between the normal to the inclined surface 94 and the normal (vertical direction) to the bottom surface 93 is θ _2E , the incident angle θ ′ ₂
Is expressed as in the following Expression 3.

[0052]

(Equation 3)

The light L2 incident on the inclined surface 94 is
The light is refracted by the inclined surface 94 and becomes the output light L4. Outgoing light L4
Emission angle theta _"2 of a value satisfying the following equation (4).

[0054]

(Equation 4)

Since the incident angle θ ′ _{1 with} respect to the bottom surface 93 is considered to be a constant determined by the maximum incident angle θmax, the output angle θ ″ ₂ of the output light L 4 is determined by the angle θ _{2E from} Expressions 3 and 4. I understand.

[0056] Similarly, the light L2 is the inclined surface 95 is incident at an incident angle theta _'3. Assuming that the angle between the normal to the inclined surface 95 and the normal to the bottom surface 93 is θ _3E , the incident angle θ ′ ₃ is expressed by the following equation 5.

[0057]

(Equation 5)

Then, the light L2 incident on the inclined surface 95 is
The light is refracted by the inclined surface 95 and becomes the output light L5. Outgoing light L5
Output angle theta _"3 becomes a value that satisfies the following Equation 6.

[0059]

(Equation 6)

Similarly to the above, it can be seen from Equations 5 and 6 that the emission angle θ ″ ₃ of the emitted light L5 is a value determined by the angle θ _3E .

Here, as shown in FIG. 5, the distance between the bottom surface 93 and the resist film 1 is defined as l _1, and the side surface 97 of the inclined surface 94 is formed.
The distance between the side end 94a (here, the end on the center side of the substrate W) and the resist film 1 is l _2, and the side surface 97 of the inclined surface 95
(Here, the center-side end portion of the substrate W) side of the end portion 95a of the distance between the resist film 1 and l _3. In addition, a vertical line passing through the end 94 a of the inclined surface 94 and the end 9 of the bottom surface 93.
3a with the vertical line passing through it (in short,
The horizontal distance between the end 94a and the end 93a) is ΔW ₁
The distance between the vertical line passing through the end 95a of the inclined surface 95 and the vertical line passing through the end 94a of the inclined surface 94 is ΔW ₂ . It is assumed that the following equation 7 is satisfied.

[0062]

(Equation 7)

When the equation (7) is satisfied, the outgoing light L 4 emitted from the end 94 a of the inclined surface 94 is shifted to the position P on the substrate W.
3, that is, the point at which the emitted light L3 emitted from the end 93a of the bottom surface 93 reaches the end of the exposure target area. Further, the emitted light L5 emitted from the end 95a of the inclined surface 95 also reaches the position P3 on the substrate W. In other words, if various conditions are set so as to satisfy Equation 7, the emitted light L3 emitted from the end 93a of the bottom surface 93, the emitted light L4 emitted from the end 94a of the inclined surface 94, and the end of the inclined surface 95 All of the emitted light L5 emitted from the portion 95a reaches the position P3, that is, the end of the exposure target area. Here, from FIG. 5, l ₂ = l ₁ + ΔW ₁ tan θ _2E and l ₃ = l ₂ + (ΔW
₂ −ΔW ₁ ) × tan θ _3E = l ₁ + ΔW ₁ tan θ _2E + (ΔW ₂ −
Because it is ΔW ₁₎ × tanθ _3E, eventually number 7 is represented as the following equation 8.

[0064]

(Equation 8)

In Equation 8, l ₁ is a value determined by the distance separating the light guide rod 90 from the substrate W, the emission angle θ ″ ₁ is equal to the maximum incident angle θmax, and the emission angle θ ″ ₂ and the emission angle θ ″. ₃ is a value determined by the angle θ _2E and the angle θ _3E , respectively.Therefore, the inclined surface 94 and the inclined surface 94 are arranged so that the emitted light L3, the emitted light L4, and the emitted light L5 reach the end (position P3) of the exposure target area. When the surface 95 is formed, ΔW ₁ and θ _2E are set so as to satisfy Expression 7 (or Expression 8).
And ΔW ₂ and θ _3E may be set. In addition,
In an actual design, the left side of Equation 7 (or Equation 8) is a constant. Therefore, if _one of ΔW _{1 and} θ _2E is determined, the other is also determined, and one of ΔW _{2 and} θ _3E must be determined. If so, the other will be decided.

For example, as an example, l ₁ = 1000 μ
m, maximum incident angle θmax = 23.2 °, refractive index n = 1.5
In order to satisfy Equation 7 when θ _2E = 30 ° and θ _3E = 45 ° under the conditions of ( ₁₎ , ΔW ₁ = 276 μm, ΔW ₂
= 503 μm. FIG. 6 is a diagram showing an intensity distribution of light emitted from the light guide rod 90 in this example. The vertical and horizontal axes in FIG. 13 are the same indices as in FIG. However, in FIG. 6, 0 μm is set immediately below the end 93 a of the bottom surface 93 in the vertical direction. As is clear from comparison with FIG. 13, the increase in light intensity has a steep distribution,
The area where the relative strength is not less than 0 and less than 0.3, that is, the area where the resist remains in a tapered shape is about 110 μm.

This means that the light exit surface 92 of the light guide rod 90
Is provided around the periphery of the light guide rod 90 so as to refract the light passing through the light guide rod 90 toward the exposure target region, so that light emitted from the peripheral portion is emitted toward the exposure target region from other than the peripheral portion. This means that the boundary portion of the light irradiation area becomes clear as a result. In the present embodiment, the light guide rod 90
Inclined surface 9 that forms an obtuse angle with both bottom surface 93 and side surface 97
4 and an inclined surface 95 are used as refraction portions, and light emitted from the inclined surfaces 94 and 95 is superimposed on light emitted from the bottom surface 93 (strictly speaking, light emitted from each end portion). ), The boundary portion of the light irradiation area at the position P3 becomes clear.

In the description relating to FIG. 5, only the case where the light incident on the light guide rod 90 at the maximum incident angle θmax is emitted from the ends of the bottom surface 93, the inclined surface 94, and the inclined surface 95 has been described. The maximum incident angle θ
Some light is incident at an incident angle less than max, and the bottom surface 9
3. Needless to say, light exiting from other than the end portions of the inclined surface 94 and the inclined surface 95 exists. But these are
In each case, the light is emitted toward the inside of the exposure target area (right side of the position P3 in FIG. 5), and therefore does not affect the boundary of the irradiation area, but rather contributes to the superposition of the light. is there. In other words, the maximum incident angle θ
The light incident on the light guide rod 90 at max and the bottom surface 9
3. If the inclined surfaces 94 and 95 are formed such that the light emitted from the ends of the inclined surfaces 94 and 95 reaches the end (position P3) of the exposure target region, the boundary between the light irradiation regions Part becomes clear. And Equation 7 (or Equation 8)
Is an inclined surface such that light incident on the light guide rod 90 at the maximum incident angle θmax and emitted from the ends of the bottom surface 93, the inclined surface 94, and the inclined surface 95 reaches the end of the exposure target region. This is a relational expression that defines the conditions for forming 94 and the inclined surface 95.

When the boundary of the light irradiation area becomes clear,
As shown in FIG. 13, the resist remaining in a tapered shape at the boundary between the exposure target region and the region where the resist is to be left (the inner peripheral portion of the exposure target region EA1 in FIG. 4) is reduced. Further, in the exposure apparatus of the present embodiment, since it is not necessary to use an imaging optical system such as a lens as in the second conventional method, the throughput is reduced, the weight is increased, the cost is increased, and the required space is increased. Can be prevented.

Incidentally, in the exposure apparatus of this embodiment, the two-step inclined surface 9 composed of the inclined surface 94 and the inclined surface 95 is used.
6, an anti-reflection film composed of a dielectric multilayer film is deposited. This antireflection film is for preventing reflection of light. By depositing an anti-reflection film on the inclined surface 94 and the inclined surface 95, reflection of light traveling in the light guide rod 90 at the time of emission from the inclined surface 94 and the inclined surface 95 is prevented, and light transmittance is increased. be able to. Further, it is possible to prevent the light reflected by the substrate W after being emitted from the light guide rod 90 from being re-reflected. In particular, when re-reflection occurs on the inclined surface 94 and the inclined surface 95, light is reflected toward a region on the center side of the substrate W (a region where a resist is left and a pattern is formed). The significance of preventing is significant. Note that such an antireflection film may be deposited not only on the inclined surface 94 and the inclined surface 95 but also on the entire exit surface 92 including the bottom surface 93.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described example.
For example, in the above embodiment, the edge of the substrate W is exposed, but a predetermined area of the substrate W other than the edge may be exposed. The exposure target area when performing such area exposure is, for example, an area EA2 in FIG. That is, the exposure target area EA2 is in contact with the area where the resist is to be left over the entire outer periphery thereof. In this case, the inclined surface 94 and the inclined surface 95 are formed on the entire periphery of the emission surface 92 of the light guide rod 90, specifically, on four sides of the rectangular emission surface 92, so that the entire outer periphery of the light irradiation region is formed. , The boundary portion becomes clear, and the resist remaining in the taper shape at the boundary portion between the exposure target region EA2 and the region outside the region is reduced.

On the other hand, when the edge of the substrate W is exposed as in the above-described embodiment, it is sufficient if the inner peripheral boundary portion of the exposure target area EA1 in FIG.
The two-step inclined surface 96, which is a refraction portion, is connected to the exit surface 9
It is sufficient that the light-emitting portion 2 is provided in a portion facing the center side of the substrate W, that is, a portion that emits light to the inner peripheral boundary portion of the exposure target area EA1. Specifically, a two-step inclined surface 96 is provided on one side of the rectangular emission surface 92.

In addition to the above, a refraction portion can be provided at an arbitrary portion around the emission surface 92 of the light guide rod 90 according to the mode of the exposure target region.

In the above embodiment, the refracting portion is a two-step inclined surface 96 composed of the inclined surface 94 and the inclined surface 95. However, the number of inclined surfaces as the refracting portion is not limited to two but may be one. Or three or more stages. Even if the inclined surface as the refraction portion has one step, the light is refracted, so that the effect of superimposing the light from the inclined surface can be obtained. However, the effect of superimposing the light can be obtained by forming two or more steps. It is easy to obtain, and the boundary of the irradiation area becomes clearer. However, since processing becomes complicated depending on the number of steps of the inclined surface, it is preferable to determine the number of steps based on a balance between optical characteristics and workability.

Further, in the above-described embodiment, the refraction portion is formed as an inclined surface, but the present invention is not limited to this.
The bending section may be configured as follows.

For example, as shown in FIG.
A Fresnel surface 99a may be formed over the entire periphery of the zero emission surface 92. The light guide rod 90 of FIG. 7 has a Fresnel surface 99a formed over the entire periphery of the light exit surface 92, and is therefore suitable for the above-described area exposure.

FIG. 8 is a diagram showing how light is emitted from the Fresnel surface 99a. In the same manner as the inclined portion of the refraction portion, the light emitted from the peripheral portion can be superimposed on the light emitted from other than the peripheral portion toward the exposure target region, and the boundary portion of the irradiation region can be sharpened. it can. In addition, when the refraction portion is the Fresnel surface 99a, a relatively large refracting power can be obtained, and fine settings can be made. In addition,
Of course, the Fresnel surface 99a may be formed on a part of the periphery of the emission surface 92.

Further, as shown in FIG.
A diffraction surface 99b may be provided on the periphery of the light exit surface 92. The diffraction surface 99b is obtained by changing the interval between linear portions through which light can pass due to shading and unevenness. That is, the diffraction surface 99b is a diffraction grating in which the pitch is continuously changed. When the pitch of the diffraction grating changes, the direction of light that causes diffraction also changes. Since this is the same as refracting light, the same effect can be obtained as in the case where the refraction portion is formed as an inclined surface as in the above embodiment.

Further, as shown in FIG.
The periphery of the zero emission surface 92 may be a cylindrical portion 99c. The cylinder shape is a shape like a part of a cylindrical side surface. The peripheral portion of the emission surface 92 is formed as a cylindrical portion 99c.
Is equivalent to infinitely increasing the number of steps of the inclined surface in the above embodiment. Therefore, even in this case, it is possible to obtain the same effect as when the refraction portion is formed as an inclined surface.

Further, as shown in FIG.
0 is a GRIN surface (Gradient Inde
x) It may be 99d. The GRIN surface 99d is a surface whose refractive index continuously decreases from the center of the light guide rod 90 toward the peripheral portion. In this case, FIG.
As shown in FIG. 1, the same effect can be obtained as when the refraction portion is formed as an inclined surface.

[0081]

As described above, according to the first aspect of the present invention, the light guide rod exposes at least a part of the periphery of the light exit surface of the light guide rod to light passing through the light guide rod. Since the light has a bent portion bent toward the target region, light emitted from the peripheral portion can be superimposed on light emitted toward the exposure target region from a portion other than the peripheral portion. The boundary portion of the light irradiation area can be sharpened without increasing the cost and the space required.

According to the second aspect of the present invention, the bent portion is a refraction portion for refracting light emitted from the peripheral portion of the exit surface toward the exposure target region. The effect can be obtained.

According to the third aspect of the present invention, the effect of the first aspect of the present invention can be easily obtained because the refracting portion includes the inclined surface which forms an obtuse angle with both the bottom surface and the side surface of the light guide rod. .

According to the fourth aspect of the present invention, the refracting portion includes a multi-step inclined surface in which the inclined surface is formed in multiple steps.
In addition to the effect of the first aspect of the invention, the boundary portion of the light irradiation area can be made clearer.

According to the fifth aspect of the present invention, the light incident on the light guide rod from the light source at the maximum incident angle is emitted from the end of the bottom surface which forms a boundary with the multi-step inclined surface among the emission surfaces. The multi-step inclined surface is formed in such a manner that the divided light and the light emitted from the side end portions of the respective inclined surfaces constituting the multi-step inclined surface reach the end of the exposure target area. The effects of the invention can be reliably obtained.

According to the invention of claim 6, since the anti-reflection film for preventing light reflection is formed on at least the inclined surface, the reflection of light at the time of emission from the inclined surface is prevented, and The transmittance can be increased, and the light reflected on the substrate can be prevented from being re-reflected.

According to the seventh aspect of the present invention, the region to be exposed is an edge portion of the substrate, and the refraction portion is provided in a portion of the peripheral portion of the light exit surface of the light guide rod facing the center side of the substrate. Therefore, even when only the edge of the substrate is exposed,
The same effect as that of the invention can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of an exposure apparatus according to the present invention.

FIG. 2 is a diagram showing a configuration of an exposure head of the exposure apparatus of FIG.

FIG. 3 is a partial perspective view of the light guide rod of FIG. 2;

FIG. 4 is a diagram showing an exposure target area.

FIG. 5 is a diagram for explaining the behavior of light emitted from the emission surface of the light guide rod.

FIG. 6 is a diagram illustrating an example of an intensity distribution of light emitted from a light guide rod.

FIG. 7 is a diagram illustrating another example of a refraction portion formed on an emission surface of a light guide rod.

FIG. 8 is a diagram showing how light is emitted from the Fresnel surface of FIG. 7;

FIG. 9 is a view showing another example of the refraction portion formed on the light exit surface of the light guide rod.

FIG. 10 is a diagram showing another example of the refraction portion formed on the emission surface of the light guide rod.

FIG. 11 is a diagram showing another example of the refraction portion formed on the light exit surface of the light guide rod.

FIG. 12 is a view for explaining light irradiation from a conventional light guide rod.

13 is a diagram showing an intensity distribution of light emitted from the conventional light guide rod of FIG.

[Explanation of symbols]

 54 xenon flash lamp 90 light guide rod 92 emission surface 93 bottom surface 94,95 inclined surface 96 two-step inclined surface 97 side surface W substrate

Claims (7)

[Claims] 1. An exposure apparatus for irradiating an exposure target area on a substrate to be exposed with light, thereby exposing the exposure target area, comprising: a light source for irradiating the light; and a light from the light source. A light guide rod that guides toward the exposure target area on the substrate and emits the light from an emission surface facing the exposure target area; and a light guide rod is provided at a peripheral portion of the emission surface. An exposure apparatus, comprising, at least in part, a bent portion for bending light passing through the light guide rod toward the exposure target region. 2. The exposure apparatus according to claim 1, wherein the bent portion is a refraction portion that refracts light emitted from a peripheral portion of the emission surface toward the exposure target area. . 3. The exposure apparatus according to claim 2, wherein the refracting portion includes an inclined surface that forms an obtuse angle with both the bottom surface and the side surface of the light guide rod. 4. The exposure apparatus according to claim 3, wherein the refraction section includes a multi-step inclined surface in which the inclined surface is formed in multiple steps. 5. The exposure apparatus according to claim 4, wherein the light is incident from the light source to the light guide rod at a maximum incident angle, and the bottom surface forming a boundary with the multi-step inclined surface of the exit surface. The multi-step inclined surface is formed such that light emitted from an end of the multi-step inclined surface and light emitted from a side end of each inclined surface constituting the multi-step inclined surface reach an end of the exposure target region. An exposure apparatus comprising: 6. The exposure apparatus according to claim 3, wherein an anti-reflection film for preventing reflection of light is formed on at least the inclined surface. 7. The exposure apparatus according to claim 1, wherein the exposure target area is an edge of a substrate, and the bent portion is a peripheral portion of an emission surface of the light guide rod. An exposure apparatus, provided at a portion facing a center side of the substrate.