JPH0610900U - Exposure equipment - Google Patents

Abstract

(57) [Abstract] [Purpose] To reduce the exposure unevenness in the vertical direction when SOR light is reflected by an oscillating mirror for exposure. [Structure] SOR light 29 is reflected by an oblique incidence mirror 30 and is incident on an exposure unit. By swinging the oblique incidence mirror 30 around the swing shaft 34, the SOR light 29 is swung in the vertical direction to secure the exposure area in the exposure unit. Oblique incidence mirror 3
The 0 reflection surface 30a is formed as a conical surface. This allows S
The difference in the condensing power of the OR light 29 with respect to each part in the vertical direction is reduced, and the unevenness of exposure in the vertical direction is reduced.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an exposure apparatus for performing exposure such as lithography using SOR light (synchrotron radiation), which reduces unevenness in vertical exposure when the SOR light is reflected by an oscillating mirror and exposed. is there.

[0002]

[Prior art]

 In recent years, small synchrotrons are expected to be applied as synchrotron radiation (SOR) devices to various fields such as ultra-ultra LSI circuit creation, medical field diagnostics, molecular analysis, and structural analysis.

FIG. 2 shows an outline of a small SOR device. An electron beam generated by a charged particle generator (electron gun, etc.) 10 is accelerated to near the speed of light by a linear accelerator (linac) 12, and is deflected by a deflecting electromagnet 16 of a beam transport unit 14 to cause an inflector 18 to move. The light is injected into the storage ring 22 via. The electron beam incident on the storage ring 22 is converged by the converging electromagnets 23 (for vertical direction) and 25 (for horizontal direction) while being given energy by the high-frequency acceleration cavity 21, and is deflected by the deflection electromagnet 24 to be accumulated. Continue to orbit inside. Synchrotron radiation generated when being deflected by the deflecting electromagnet 24 is sent to the exposure unit 28 through the beam channel 26 and used as a light source for lithography or the like for producing an ultra-ultra LSI circuit.

The SOR light spreads in the horizontal direction but has a narrow width in the vertical direction. Therefore, when it is used for exposure such as lithography, an oblique incidence mirror is arranged in the beam channel, SOR light is incident on this oblique incidence mirror, and this oblique incidence mirror is swung in the vertical direction, thereby The light is shaken vertically to secure the exposure area.

FIG. 3 is a side view showing a configuration example of the oblique incidence mirror arranged in the beam channel and its swing mechanism. An oblique incidence mirror 30 is arranged in the light extraction line 26. The grazing incidence mirror 30 is made of oxygen-free copper SiC, Au, Pt, or the like, reflects the SOR light 29, and exits from a beryllium window 32 attached to the center of the window plate 31 at the end of the light extraction line 26. Then, the exposure target 35 (mask and wafer) in the exposure unit 28 is exposed.

The grazing incidence mirror 30 is supported so as to be vertically swingable about a shaft 34 as a fulcrum. A rod 38 of a mirror swing mechanism 36 is attached to the end of the oblique incidence mirror 30. The rod 38 moves in the vertical direction by the rotation of the cam 42 driven by the motor 40, swings the oblique incidence mirror 30 in the vertical direction, and swings the SOR light 29 in the vertical direction. Thereby, the exposure area of the exposure target 35 is secured.

When the grazing incidence mirror 30 is formed of a plane mirror, the SOR light 29 spreads in the horizontal direction, and only a part of the SOR light 29 is effectively used for exposure, so that the irradiation power becomes low. Therefore, as shown in FIG. 4, the wafer 33 is exposed by forming a cylindrical mirror and converging the SOR light 29 in the horizontal direction to form parallel light.

[0008]

[Problems to be solved by the device]

 The state of incidence of the SOR light 29 on the reflecting surface 30a of the oblique incidence mirror 30 is shown in a vertical sectional view in FIG. According to this, the angle α (twice the incident angle) between the upper portion 29a and the lower portion 29b of the SOR light 29 is 90 ° <α1 <α2 <180 °.

On the other hand, the condition for making the SOR light 29 into parallel light by the oblique incidence mirror 30 is given by the following equation.

R = 2f sin α (1) However, R: radius of curvature of the reflecting surface of the oblique incidence mirror f: distance from the light source to the oblique incidence mirror α: angle twice the incident angle According to this, parallel light is maintained To do so, the radius of curvature R must increase as sin α increases. However, since the radius of curvature R is always constant in the grazing incidence mirror 30 of FIG. 4 configured by a cylindrical mirror, in the situation of FIG. 5 where sin α1> sin α2, the condensing power for the SOR light upper part 29a is to the SOR light lower part 29b. It becomes weaker than the light collecting power. Therefore, the beam profile of the SOR light 29 projected onto the exposure target 35a becomes a fan shape as shown in FIG. 6, and when this is swung up and down by the swing of the oblique incidence mirror 30, the exposure shape as shown in FIG. 29 'is also fan-shaped. For this reason, there is a drawback in that the intensity of the light applied to the exposure target 35 becomes weaker because it spreads in the upper part 35b and becomes stronger because it narrows in the lower part 35b and uneven exposure occurs in the vertical direction.

The present invention intends to solve the above-mentioned problems in the prior art and provide an exposure apparatus that reduces the vertical exposure unevenness when the SOR light is reflected by an oscillating mirror for exposure. To do.

[0012]

[Means for Solving the Problems]

 The present invention is directed to a beam channel through which SOR light emitted from a deflection position of an electron beam that circulates around a storage ring is guided, an optical axis of the SOR light disposed in the beam channel to reflect the SOR light. And an oscillating mechanism that oscillates the grazing-incidence mirror that bends the grazing-incidence mirror with the horizontal axis that is perpendicular to the optical axis of the SOR light and the SOR light reflected by the grazing-incidence mirror. In the exposure apparatus having an exposure unit that guides light to expose the object to be exposed, the reflecting surface of the oblique incidence mirror is composed of a concave curved surface, and the central axis of the curved surface is the light of the SOR light. It is characterized in that it is formed in a vertical plane including the axis, and the shape of this curved surface is formed so as to gradually reduce the curvature in the traveling direction of the SOR light.

[0013]

According to this, the radius of curvature is large at the position near the light source of the oblique incidence mirror, and the radius of curvature is small at the position near the exposure apparatus, so that the condensing power for the SOR light is in the vertical direction position of the SOR light. Regardless, it becomes almost constant, and it is possible to reduce the exposure unevenness when the SOR light is vertically swung.

[0014]

【Example】

 An embodiment of this invention will be described below. The entire exposure apparatus is constructed as shown in FIG. 2, and the SOR light emitted from the deflection position of the storage ring 22 is guided to the exposure unit 28 through the beam channel 26. As shown in FIG. 3, a mirror swing mechanism 36 is disposed in the beam channel 26, and the oblique incidence mirror 30 is swung to swing the SOR light 29 up and down to expose the exposure target 35 (mask and wafer) of the exposure unit 28. ) Is exposed.

An embodiment of the grazing incidence mirror 30 according to the present invention is shown in FIG. 1 in a perspective view seen from the reflecting surface 30a side. The grazing incidence mirror 30 is made of oxygen-free copper, Sic, Au, Pt, or the like. The shape of the reflecting surface 30a is a conical surface. The central axis 50 of the cone is formed in a vertical plane including the SOR optical axis 29x, and the radius of curvature R is formed to be gradually smaller in the traveling direction of the SOR light 29 (R1> R2).

The SOR light 29 is reflected by the oblique incidence mirror 30 as shown in FIG. 5 when viewed in a longitudinal sectional view, and sin α1> sin α2, but the radius of curvature of the position where the upper portion 29a of the SOR light is reflected. The radius of curvature R2 at the position where R1 and the SOR light lower portion 29a are reflected is R1> R2. Therefore, from the above formula (1), if the shape of the cone is determined so that R1: R2 = sin α1: sin α2, the condensing power for the SOR light 29 becomes almost constant regardless of the position in the upward and downward directions. , Parallel light is emitted at almost any position in the vertical direction.

According to this, as shown in FIG. 8, the beam profile of the SOR light 29 projected on the exposure surface 35a of the exposure target 35 has a shape in which the width of the upper portion 29a and the width of the lower portion 29b are not so different from each other. Become. Therefore, when this is swung up and down by the swing of the oblique incidence mirror 30, the result becomes as shown in FIG. 9, and the change in the exposure width due to the vertical position is smaller than in the conventional case of FIG. The uneven exposure in the direction is reduced.

[0018]

[Example of change]

 The invention can also be used for exposures other than lithography.

[0019]

[Effect of device]

 As described above, according to this, the radius of curvature is large at the position near the light source of the oblique incidence mirror, and the radius of curvature is small at the position near the exposure apparatus. It becomes almost constant regardless of the directional position, and it is possible to reduce the exposure unevenness when the SOR light is oscillated in the vertical direction.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of an oblique incidence mirror according to the present invention.

FIG. 2 is a plan view showing an outline of an SOR device.

FIG. 3 is a vertical sectional view showing an example of a mirror swing mechanism.

FIG. 4 is a perspective view showing a conventional oblique incidence mirror having a cylindrical surface.

FIG. 5 is a vertical cross-sectional view showing a state of incidence and reflection of SOR light on an oblique incidence mirror.

6 is an SOR on an exposure surface by the oblique incidence mirror of FIG.
It is a figure which shows the projection profile of light.

FIG. 7 is a diagram showing an exposure shape on an exposure surface when the oblique incidence mirror in FIG. 4 is swung.

8 is an SOR on the exposure surface by the grazing incidence mirror of FIG.
It is a figure which shows the projection profile of light.

9 is a diagram showing an exposure shape on an exposure surface when the oblique incidence mirror of FIG. 1 is swung.

[Explanation of symbols]

 22 Storage Ring 26 Beam Channel 28 Exposure Part 29 SOR Light 29x SOR Light Optical Axis 30 Oblique Incidence Mirror 30a Reflective Surface 34 Swing Axis 35 Exposure Target 36 Swing Mechanism 50 Central Axis of Curved Surface

Claims (1)

[Scope of utility model registration request] 1. A beam channel for guiding SOR light emitted from a deflection position of an electron beam circulating in a storage ring, and the SOR disposed in the beam channel.
An oblique incidence mirror that reflects light and bends the optical axis of the SOR light; An exposure apparatus comprising: an exposure unit that guides the SOR light reflected by the oblique incidence mirror to expose an exposure object, wherein the reflection surface of the oblique incidence mirror is a concave curved surface,
The center axis of the curved surface is formed in a vertical plane including the optical axis of the SOR light, and the shape of the curved surface is formed so as to gradually reduce the curvature in the traveling direction of the SOR light. An exposure apparatus.