JP2022050812A - Light source device and exposure device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable illumination light to be incident on an integrator incident surface in which a decrease in illumination efficiency is suppressed regardless of a lamp lighting condition.
SOLUTION: In an exposure device 10 provided with a light source device 20 for incidenting illumination light on an integrator 13, the light source device 20 is composed of a lamp unit including a discharge lamp 30 and a concave reflector 40. Then, the electrode center C of the discharge lamp 30 is offset from the focal point C0 along the Y axis along the vertical direction with respect to the concave reflector 40 and the bottom side of the reflector center axis Z.
[Selection diagram] Fig. 2

Description

The present invention relates to a light source device, and more particularly to an incident of illumination light on an optical element such as an integrator.

As a light source device used for a projector, an exposure device, or the like, a light source device composed of a lamp unit including a discharge lamp and a reflector is known. The light emitted from the discharge lamp is reflected by the reflector and guided to the illumination optical system including the optical element (integrator such as a condenser lens, a rod lens, and a fly-eye lens). The illumination light is equalized by an integrator, becomes parallel light by a collimator lens, and is applied to a light modulation element array such as a DMD, a work, or the like.

The tip of the electrode of the discharge lamp wears due to aging, and the proportion of light incident on the integrator decreases with the lapse of lighting time, resulting in a decrease in illuminance. In order to prevent this, in a multi-lamp type light source device provided with a plurality of lamp units, light having an irradiation area wider than the incident surface of the integrator is incident on the integrator (see Patent Document 1).

Japanese Unexamined Patent Publication No. 2009-302218

In the light source device installed in projectors, exposure devices, etc., the light source device so that the lamp axis is substantially horizontal along the lamp axis for reasons such as good expression of halogen cycle and suppression of electrode wear when an AC type discharge lamp is used. Is required to be installed. Therefore, the reflector is held so that its open end is substantially in the vertical direction.

When the reflector thermally expands while the lamp is lit, the central axis of the reflector fluctuates along the vertical direction due to the holding structure of the reflector and the like. As a result, the luminous flux cross section (irradiation pattern) of the light incident on the integrator changes due to the difference in temperature environment between immediately after the lamp is turned on and when the lamp is stably turned on, and a part of the illumination light does not enter the integrator incident surface. Lighting efficiency is reduced.

Therefore, there is a need for a light source device that enables illumination light to be incident on an integrator incident surface that suppresses a decrease in lighting efficiency regardless of the lamp lighting condition.

A light source device according to an aspect of the present invention includes a lamp and a concave reflector whose opening end is aligned along the vertical direction and reflects the illumination light emitted from the lamp. The concave reflector can be composed of, for example, an ellipsoidal or parabolic reflector. It is also possible to configure a single lamp, or to arrange a plurality of lamp units each composed of a lamp and a concave reflector side by side in a row.

The illumination light travels along the central axis of the concave reflector and is incident on an optical element arranged in the traveling direction of the illumination light. The optical element can be configured by, for example, an integrator. Further, the illumination light is configured to be incident with a luminous flux corresponding to the size of the incident surface. That is, it does not have an irradiation area in which the illumination light is much larger than the incident surface of the optical element or an irradiation area in which the illumination light is incident on only a small part of the incident surface, and the illumination light from the light source is not lost as much as possible. In addition, the illumination light of the light beam according to the size of the incident surface of the optical element is incident on the optical element.

In the present invention, the luminous flux cross section of the illumination light is distorted from a circular shape on the incident surface of the optical element so that the irradiation area expands along the line corresponding to the vertical direction. The degree and direction of distortion can be variously configured, and for example, the irradiation area can be distorted so as to expand to one direction side of the line. Further, it can be distorted so that the end of the irradiation area extends to one direction side of the line.

For example, if the lamp is a discharge lamp with a pair of electrodes and the concave reflector is an elliptical or parabolic reflector, the center between the electrodes is one axis with respect to the focal point of the concave reflector. A discharge lamp is arranged so as to be offset in the direction along the direction of the mirror and offset along the central axis of the reflector on the bottom side opposite to the opening end of the concave reflector. The offset amount ΔY along one axis and the offset amount ΔZ along the central axis of the reflector can be determined so as to satisfy 0.2 ≦ ΔY / ΔZ ≦ 4.

On the other hand, the light source device according to another aspect of the present invention includes a lamp and a concave reflector that forms a circular opening end and guides the illumination light emitted from the lamp in a direction along the center of the reflector. The illumination light is incident on the incident surface of the optical element with a luminous flux corresponding to the size of the incident surface. Then, on the incident surface of the optical element perpendicular to the central axis of the reflector, the irradiation area expands along a predetermined line through which the light beam cross section of the illumination light passes through the intersection with the central axis of the reflector along the traveling direction of the illumination light. It's distorted.

The exposure device according to one aspect of the present invention includes the light source device and an illumination optical system including the optical element, so that the central axis of the reflector is along the horizontal direction or in a range of a predetermined angle with respect to the horizontal direction. The light source device is installed so as to incline inside.

According to the present invention, it is possible to allow the illumination light to be incident on the integrator incident surface in which the decrease in the illumination efficiency is suppressed regardless of the lamp lighting condition.

It is a schematic block diagram of the exposure apparatus provided with the light source apparatus which is 1st Embodiment. It is a schematic sectional drawing of a light source device. It is the figure which partially enlarged the vicinity of the discharge lamp of FIG. It is a figure which showed the irradiation pattern of the illumination light incident on the incident surface of an integrator. It is a figure which showed the irradiation pattern different from FIG. It is a figure which showed the irradiation pattern when the discharge lamp is not offset arrangement. It is a figure which showed the exposure apparatus which is a 2nd Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic block diagram of an exposure apparatus including the light source apparatus according to the first embodiment.

Here, the exposure apparatus 10 is configured as a contact exposure apparatus that projects pattern light onto the substrate W using a photomask 14. The exposure device 10 includes a light source device 20 and an exposure head 11, and is lit by a light source drive unit 19 controlled by a controller 15. The exposure head 11 includes an illumination optical system 12 including an integrator 13 for equalizing the illuminance, and a photomask 14.

The light emitted from the light source device 20 passes through the illumination optical system 12 and is incident on the photomask 14. The light that has passed through the photomask 14 is projected onto the substrate W of the exposure stage 18. As a result, a predetermined pattern is formed on the substrate W.

In the exposure apparatus 10, high illuminance mode and low illuminance mode can be set. When the high illuminance mode is set by the user, high power is input to the discharge lamp 30, and when the low illuminance mode is set, the exposure lamp 30 is set. Low power input. The exposure apparatus 10 can also be configured as a maskless exposure apparatus or a projection exposure apparatus.

FIG. 2 is a schematic cross-sectional view of the light source device 20. FIG. 3 is a partially enlarged view of the vicinity of the discharge lamp 30 of FIG.

The light source device 20 is composed of a lamp unit including a discharge lamp 30 and a concave reflector 40, and here, it is composed of one lamp unit. The discharge lamp 30 is, for example, an AC type high-pressure or ultra-high pressure mercury lamp, and includes a pair of electrodes 32 and 34 in the arc tube 33. Sealing tubes 36, 38 are integrally formed at both ends of the arc tube 33 of the discharge lamp 30, and the sealing tube 38 is supported or held by a holding member 60.

The concave reflector 40 is a reflector that guides the light radiated from the discharge lamp (hereinafter referred to as illumination light) to the illumination optical system 12 side along the central axis Z of the reflector, and here, an elliptical reflector having an elliptical cross section. It is configured as. The illumination light emitted from the circular opening end 40A is incident on the incident surface 13A of the integrator of the illumination optical system 12.

The reflector central axis Z is perpendicular to the incident surface 13A of the integrator 13 as the optical axis of the illumination light, and the illumination light is incident on the incident surface 13A with a luminous flux corresponding to the area size. A folded mirror or the like may be provided between the concave reflecting mirror 40 and the integrator 13. Further, the concave reflector 40 can also be configured as a parabolic reflector.

In the concave reflector 40, the central axis (hereinafter referred to as the reflector central axis) Z of the concave reflector 40 is horizontal because of the good expression of the halogen cycle in the discharge lamp 30 and the prevention of electrode wear of the AC type discharge lamp 30. It is fixed to the holder 50 along the direction. The holder 50 has an opening 50A corresponding to the opening end 40A side, and is fixed in the apparatus so that the surface (here, referred to as a reference surface) 50S facing the opening end 40A side is along the vertical direction.

The concave reflecting mirror 40 has an open end 40A that abuts on the reference surface 50S, fits into the annular convex portion 52 provided on the reference surface 50S, and exerts a force acting from the bottom of the reflecting mirror to the reference surface 50S side. It is received and fixed. As a result, the open end 40A of the concave reflector 40 is along the vertical direction.

Since the concave reflector 40 thermally expands when the lamp is lit, the diameter size of the annular convex portion 52 is set to be larger than the size of the open end 40A of the concave reflector 40. Therefore, when the concave reflector 40 is fitted to the holder 50, the open end 40A abuts on the lower end 52B of the convex portion 52, while a gap SB is generated between the concave reflector 40 and the upper end 52A of the convex portion 52. There is.

In the present embodiment, the center C between the electrodes of the discharge lamp 30 is not located at the focal point C0 of the concave reflecting mirror 40, but the center axis Z of the reflecting mirror and the axis along the vertical direction (reference plane 50S) passing through the focal point C0 (reference plane 50S). Hereinafter, it is offset with respect to Y (referred to as the vertical axis).

Specifically, it is offset downward by ΔY along the vertical axis Y, and is offset by ΔZ along the reflector central axis Z on the opposite side (bottom side) of the open end 40A of the concave reflector 40. It is offset. Therefore, the lamp axis E of the discharge lamp 30 is located below the reflector central axis Z. There is no offset for the X-axis (perpendicular to the paper) that passes through the focal point C0 and is perpendicular to the vertical axis Y.

The offset amounts ΔY and ΔZ are determined according to the material, size, and the like of the concave reflector 40. Here, ΔY and ΔZ are defined so as to satisfy 0.2 ≦ ΔY / ΔZ ≦ 4. For example, ΔY and ΔZ satisfy ΔY / ΔZ = 1, that is, they are set to the same offset amount.

By such an offset arrangement of the discharge lamp 30 with respect to the concave reflector 40, the amount of illumination light incident on the incident surface 13A of the integrator 13 is not reduced in either the high illuminance mode or the low illuminance mode, and the decrease in illuminance can be suppressed. It is supposed to be. This will be described in detail below.

FIG. 4 is a diagram showing the shape of the light flux cross section of the illumination light incident on the incident surface 13A of the integrator 13 (hereinafter, also referred to as an irradiation pattern). FIG. 5 is a diagram showing an irradiation pattern different from that of FIG. FIG. 6 is a diagram showing an irradiation pattern when the discharge lamp 30 is not offset-arranged (the center C between the electrodes coincides with the focal point C0). First, the thermal expansion of the concave reflector 40 when the lamp is lit and the distortion of the luminous flux of the illumination light will be described based on the arrangement of the conventional discharge lamp 30 in FIG.

The integrator 13 is composed of a rod lens or the like, and here, the incident surface 13A is formed in a rectangular shape. The illumination light emitted from the circular opening end 40A of the light source device 20 is incident on the incident surface 13A of the integrator 13 as a luminous flux having a circular luminous flux cross section. Therefore, when the illumination light is incident on the entire area of the incident surface 13A of the integrator 13, it is necessary to form an irradiation pattern including the vicinity of the four corners 13K1 to 13K4 of the incident surface 13A.

On the other hand, if the amount of illumination light that deviates from the incident surface 13A of the integrator 13 and does not enter is large, the illumination efficiency is lowered and wasteful power consumption is accompanied. Therefore, it is desirable that an illumination light having a luminous flux size having a diameter from the center A0 of the incident surface 13A to the four corners 13K1 to 13K4 of the area is incident on the incident surface 13A of the integrator 13. Therefore, the concave reflector 40 and the like are designed so that the illumination is incident with a light flux having a size corresponding to the incident surface 13A of the integrator 13.

By the way, while the lamp is lit, the concave reflector 40 thermally expands, but since the opening end 40A is in contact with the lower end 52B of the convex portion 52, the entire concave reflector 40 is moved upward so that the reflector central axis Z moves upward. Is totally deformed, and the open end 40A comes into contact with the upper end 52A of the convex portion 52, and the gap SB (see FIG. 1) disappears. This causes the same deformation even at the time of transition from immediately after the lamp of the discharge lamp 30 is turned on to the time of stable lighting of the lamp. As a result, the irradiation pattern of the illumination light incident on the incident surface 13A of the integrator 13 also changes.

Generally, the concave reflector 40 and the like are designed so as to maximize the lighting efficiency in accordance with the high illuminance mode and the stable lighting of the lamp. In that case, immediately after the lamp is turned on, or in the low illuminance mode, a part of the illumination light does not enter the incident surface 13A of the integrator 13, and the illuminance decreases.

FIG. 6 shows the irradiation pattern C1 in the low illuminance mode (immediately after the lamp is lit) and the irradiation pattern C2 in the high illuminance mode (when the lamp is stably lit) on the incident surface 13A. Here, the axis that passes through the area center A0 of the incident surface 13A and is along the vertical direction of the opening end 40A of the concave reflector 40 is the y-axis, and the axis that passes through the area center A0 and is perpendicular to the y-axis is the x-axis. There is.

The y-axis corresponds to the Y-axis along the vertical direction passing through the focal point C0 of the concave reflector 40, and the x-axis corresponds to the X-axis. In the high illuminance mode (when the lamp is stably lit), the position c intersecting the incident surface 13A of the reflector center axis Z substantially coincides with the position of the area center A0. That is, the center position of the circular irradiation pattern C2 substantially coincides with the area center A0.

On the other hand, in the low illuminance mode (immediately after the lamp is turned on), the influence of the thermal expansion of the concave reflector 40 is small, so that the irradiation pattern C1 centered on the position c'which is the intersection of the incident surface 13A of the reflector center axis Z is formed. It is formed. The center of the irradiation pattern C1 is shifted downward by Δy from the area center A0 along the y-axis.

In the low illuminance mode (immediately after the lamp is turned on), no illumination light is incident on a part of the incident surface 13A (particularly near the two corners 13K1 and 13K4). Therefore, in order to obtain the required exposure amount for the substrate W, it is necessary to increase the illuminance by supplying excessive power immediately after the low illuminance mode or the lamp is lit.

On the other hand, when the irradiation area size of the irradiation patterns C1 and C2 is designed to be enlarged in advance to prevent this, the illumination light is incident on the entire area of the incident surface 13A, but the amount of illumination light deviating from the incident surface 13A area. Will increase, and the lighting efficiency will decrease.

FIG. 4 shows an irradiation pattern when the discharge lamp 30 in the present embodiment is offset. As shown in FIG. 4, in both the low illuminance mode (immediately after the lamp is lit) and the high illuminance mode (when the lamp is stably lit), the irradiation patterns C'1 and C'2 are patterns including the entire area of the incident surface 13A. It has become.

Compared with the irradiation patterns C1 and C2 in FIG. 6, the irradiation patterns C'1 and C'2 are arranged so that the end of the irradiation area expands in the positive direction of the y-axis, that is, the pattern shape extends in the + y direction. It's distorted. The y-axis positive direction corresponds to the Y-axis positive direction in the concave reflector 40, that is, the vertical direction. On the other hand, with respect to the x-axis, the irradiation patterns C'1 and C'2 are not distorted and have a symmetrical pattern shape with respect to the y-axis. In FIG. 4, the irradiation patterns C'1 and C'2 have a pattern shape close to an egg shape.

FIG. 5 is a diagram showing another irradiation pattern C "1 and C" 2. Unlike FIG. 4, in the low illuminance mode (immediately after the lamp is lit), the irradiation pattern C "1 does not include the region near the corners 13K1 and 13K4 of the incident surface 13A, and the illumination light is not incident. As is clear, the amount of non-incident illumination light is suppressed. On the other hand, the irradiation pattern C "2 is formed as an irradiation pattern including the corners 13K1 to 13K4 of the incident surface 13A. Regarding the irradiation pattern C "2, even when the illumination light is not incident on the areas near the corners 13K1 and 13K4 of the incident surface 13A, the decrease in the illumination efficiency is suppressed as compared with the case where the discharge lamp 30 is not offset.

As described above, according to the present embodiment, in the exposure device 10 provided with the light source device 20 for incident the illumination light on the integrator 13, the light source device 20 includes a lamp unit including a discharge lamp 30 and a concave reflecting mirror 40. Will be done. The center C between the electrodes of the discharge lamp 30 is offset from the focal point C0 along the Y-axis along the vertical direction with respect to the concave reflector 40 and the bottom side of the central axis Z of the reflector.

As a result, the irradiation patterns C'1 and C'2 incident on the incident surface 13A of the integrator 13 are circular so that the irradiation area expands in the + direction of the y-axis according to the vertical direction (upward direction of the device). The irradiation pattern has distortion with respect to the shape pattern. With such an irradiation pattern, the illumination light can be effectively incident on the integrator 13 without deteriorating the illumination efficiency in both the low illuminance mode (immediately after the lamp is lit) and the high illuminance mode (when the lamp is stably lit). can.

As described above, the offset amounts ΔY and ΔZ are set so as to satisfy 0.2 ≦ ΔY / ΔZ ≦ 4. This is because if ΔZ is too large with respect to ΔY, the irradiation pattern itself is only deformed and the distortion is small, and if ΔZ is too small with respect to ΔY, the irradiation pattern becomes extremely distorted.

In FIGS. 4 to 6, the incident surface 13A of the integrator 13 is formed in a rectangular shape, but it is also possible to make it a rectangular shape or a circular shape instead. Even in that case, the same effect can be obtained by distorting the irradiation pattern in the positive direction of the y-axis.

The distortion of the irradiation pattern may be realized by an arrangement other than the offset arrangement of the discharge lamp 30. For example, it is possible to distort the irradiation pattern by deforming the shape of the open end of the concave reflector instead of the circular shape. Further, a concave reflecting mirror having an elliptical irradiation pattern may be configured.

Therefore, it is also possible to distort the irradiation pattern in both ± directions of the y-axis to form an ellipse. It is also possible to make an irradiation pattern having an asymmetrical distortion with respect to the y-axis.

FIG. 7 is a diagram showing an exposure apparatus according to a second embodiment.

The exposure device 10'includes a multi-lamp type light source device 20', and the light source device 20' includes a plurality of lamp units 20N including a concave reflector 40 and a discharge lamp 30. The plurality of lamp units 20N are arranged in a row along the vertical direction, and each lamp unit 20N is held by a holder so that its open end is along the vertical direction, as in the first embodiment.

The illumination light from the light source device 20'is reflected by the mirrors M1 and M2 and is incident on the incident surface 13A of the integrator 13. At this time, the illumination light of each lamp unit is incident on the incident surface 13A of the integrator 13.

Even with such a multi-lamp type light source device 20', deviations near the upper and lower ends of the irradiation pattern occur in the illuminance mode (immediately after the lamp is lit) and the high illuminance mode (when the lamp is stably lit). Therefore, as in the first embodiment, the center between the electrodes of each discharge lamp is offset with respect to the focal point of the concave reflector, and the irradiation pattern is distorted in the direction corresponding to the vertical direction in each lamp unit. By doing so, it is possible to make the light incident on the incident surface 13A of the integrator 13 while suppressing the decrease in the lighting efficiency. Instead of arranging the plurality of lamp units 20N in the vertical direction, they may be tilted at a predetermined angle (for example, within a range of ± 20 °) and fixedly arranged.

The light source device shown in the first and second embodiments can be applied to a device other than the exposure device, for example, a projector. In this case, the open end of the concave reflector 40 may be positioned and fixed according to the offset arrangement direction of the discharge lamp 30.

10 Exposure device 13 Integrator 20 Light source device 30 Discharge lamp 40 Concave reflector

Claims (8)

With a lamp
It is equipped with a concave reflector whose opening end is aligned along the vertical direction and reflects the illumination light emitted from the lamp.
The illumination light is incident on the incident surface of the optical element with a luminous flux corresponding to the size of the incident surface.
A light source device characterized in that, on the incident surface of the optical element, the light flux cross section of the illumination light is distorted from a circular shape so that the irradiation area expands along a line corresponding to the vertical direction. With a lamp
It is provided with a concave reflector that forms a circular end and guides the illumination light emitted from the lamp in a direction along the center of the reflector.
The illumination light is incident on the incident surface of the optical element with a luminous flux corresponding to the size of the incident surface.
On the incident surface of the optical element perpendicular to the central axis of the reflector, the light source cross section is distorted so that the irradiation area expands along a predetermined line passing through the intersection with the central axis of the reflector. Light source device. The light source device according to claim 1 or 2, wherein the illumination light is distorted so that the irradiation area expands in one direction of the line. The light source device according to any one of claims 1 to 3, wherein the illumination light is distorted so that the end of the irradiation area extends in one direction of the line. The lamp is a discharge lamp provided with a pair of electrodes.
The concave reflector is an ellipsoidal or parabolic reflector.
The center between the electrodes is offset in the direction along the one axis with respect to the focal point of the concave reflector, and along the central axis of the reflector on the bottom side opposite to the open end of the concave reflector. The light source device according to any one of claims 1 to 4, wherein the discharge lamp is arranged so as to be offset. The fifth aspect of claim 5 is characterized in that the offset amount ΔY along one axis and the offset amount ΔZ along the central axis of the reflector are set to satisfy 0.2 ≦ ΔY / ΔZ ≦ 4. Light source device. A plurality of lamp units each composed of the lamp and the concave reflector are arranged side by side in a row.
The light source device according to any one of claims 1 to 6, wherein the illumination light from the plurality of lamp units is incident on the incident surface of the optical element. The light source device according to any one of claims 1 to 7.
It is equipped with an illumination optical system including the optical element.
An exposure device characterized in that the light source device is installed so that the central axis of the reflector is tilted along the horizontal direction or within a range of a predetermined angle with respect to the horizontal direction.

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