JP3441742B2 - SR-X-ray mirror unit - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synchrotron radiation X-ray (SR-X-ray) exposure apparatus for transferring and printing a mask pattern on a substrate such as a wafer. Regarding the SR-X-ray mirror unit, especially in the batch exposure method,
-An SR-X-ray mirror unit and a SR-X-ray mirror unit capable of maintaining a constant exposure amount of a substrate by detecting and eliminating a relative displacement between a mirror and X-rays during X-ray exposure.
The present invention relates to an X-ray incident position detection method suitable for this . 2. Description of the Related Art In recent years, with the increasing integration of semiconductors, 100
Minimum line width of 1 / 4μm for DRAM of mega bit or more
Synchrotron radiation X-ray (SR-X-ray) exposure equipment capable of transferring and printing fine patterns of
Its practical application is based on SOR (Synchrontron Or).
The SR-X-ray in the form of a sheet beam extracted from a (bital Radiation) ring has been greatly advanced by an improvement in a batch exposure system in which the convex mirror diverges the SR-X-ray in a direction perpendicular to the orbital surface of the SOR ring. In the batch exposure method, it is necessary to control the relative position and attitude (rotation and tilt state) of the mirror with respect to the sheet beam SR-X-ray drawn out of the SOR ring with high precision. That is, the traveling direction of the sheet beam SR-X-ray is the z-axis direction, and the thickness direction is the y-direction.
When the axial direction and the width direction are defined as the x-axis direction, the reflecting surface of the mirror is rotated in the three axial directions (x, y, z) and the rotation directions (ωx, ωy, ω
z) is required to be positioned with high accuracy. Further, during the X-ray exposure, if the relative positional relationship between the SR-X-rays and the mirror changes due to vibration, temperature change, fluctuations of the SR-X-rays, etc., the X-ray magnification by the mirror changes. Since this causes uneven illuminance, it is necessary to take prompt measures to keep the exposure amount uniform. In particular, the displacement in the y-axis direction and the rotation around the x-axis result in a large change in the reflection angle of the mirror, and therefore need to be continuously controlled during the exposure. According to the simulation, it has been found that if there is a displacement of ± 2 μm in the y-axis direction, illuminance unevenness of 0.1% occurs on the wafer surface. SUMMARY OF THE INVENTION [0005]
The position control as described above is indispensable for the RX X-ray mirror unit.
A countermeasure for the relative displacement between the X-ray and the mirror has not been solved. SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned unresolved problems of the prior art, and discloses an SR-X during exposure.
To eliminate the relative positional deviation between the line and the mirror to prevent uneven illuminance, and an object thereof is to provide a SR-X-ray mirror unit which can realize uniform exposure. In order to achieve the above object, an SR-X-ray mirror unit of the present invention supports a mirror having a reflecting surface for expanding an X-ray in a desired direction. a mirror support, wherein the X-ray the X-ray position sensor provided on the mirror support and the integral for the detecting the direction and amount of misalignment against the reflecting surface of said reflecting the mirror support And a control circuit for controlling the driving means in accordance with an output signal of the X-ray position sensor to adjust the displacement. . In addition, a vacuum chamber, a mirror support for supporting a mirror having a reflecting surface for expanding X-rays in a desired direction in the vacuum chamber, and a direction of displacement of the X-rays with respect to the reflecting surface. An X-ray position sensor provided integrally with the mirror in the vacuum chamber for detecting an amount and an amount of the mirror, and the mirror support is moved by an output of the X-ray position sensor to move the mirror support. And a mechanism for adjusting the displacement. A mirror support for supporting a mirror having a reflecting surface for expanding X-rays in a desired direction;
An X-ray detector for detecting a displacement of a line in a direction perpendicular to the reflection surface; a driving unit for moving the mirror support in a direction perpendicular to the reflection surface;
A control circuit for controlling the driving means in accordance with an output signal of the line detector to adjust the displacement, wherein the mirror is disposed in a vacuum chamber, and the mirror support is provided outside the vacuum chamber. The space between the opening of the vacuum chamber and a connecting means for connecting the mirror and the mirror support is sealed by a bellows, and a top plate integrated with the vacuum chamber and the mirror support are provided. A counter bellows may be provided between the body and the top of the body, and the inside of the counter bellows may be depressurized similarly to the vacuum chamber. A mirror support for supporting a mirror having a reflection surface for expanding X-rays in a desired direction, and an X-ray for detecting a displacement of the X-rays in a direction perpendicular to the reflection surface. A line detector, driving means for moving the mirror support in a direction perpendicular to the reflection surface, and controlling the driving means by an output signal of the X-ray detector to adjust the displacement. It is preferable that the mirror support is supported by guide means so as to be reciprocally movable, and cooling means is provided in the vicinity of both linear guide parts. Also, the X-ray incident position of the present invention
The position detection method detects the direction and amount of X-ray displacement.
X-ray position sensor for mirroring with mirror support
And the output signal of the X-ray position sensor.
The relative displacement of the incident X-ray with respect to the mirror reflection surface
It is characterized by doing. During X-ray exposure, when the optical path of the X-ray is displaced in the vertical direction with respect to the reflecting surface of the mirror to cause a relative positional shift, the X-ray position sensor detects the direction of the positional shift. Yo
Beauty amount is examined knowledge, the drive means is driven according to the output signal, moving the mirror so as to eliminate the relative positional deviation. By providing a counter bellows on the mirror support and depressurizing the inside thereof similarly to the vacuum chamber, the pressure applied to the mirror support outside the vacuum chamber and supporting the mirror disposed inside the vacuum chamber is reduced. Eliminates imbalance and prevents changes in attitude due to fluctuations in atmospheric pressure. Further, the mirror support and the guide means are cooled to prevent deformation due to heat generated by the drive means. An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a partially cutaway perspective view showing this embodiment, and FIG. 2 is a side view showing a state where a detector unit and a shutter unit of this embodiment are removed. [0014] A part of the cylindrical surface is formed as a downward reflecting surface (mirror opposite surface ).
Convex mirror to the reflecting surface) (hereinafter referred to as "mirror") 1
01 is held by a mirror holder 102, and the holder 102 is detachably fixed to a holder support plate 103. The retainer support plate 103 is fixed to a lower end of a mirror support bar 104 serving as a connecting means, and the mirror support bar 104 is disposed above the vacuum chamber 105 via an opening provided on an upper wall of the vacuum chamber 105. It is connected to the mirror support 106. The drive unit of the shutter unit S adjacent to one end of the mirror 101 is supported by the upper wall of the vacuum chamber 105. A bellows 1 is provided between the periphery of the opening of the vacuum chamber 105 and the flange of the mirror support rod 104.
07 is provided, and the mirror support bar 104 is placed in a vacuum atmosphere of the vacuum chamber 105 (for example, 10 ⁻⁷ to 10 ⁻¹⁰ torr).
(about r) can be freely moved up and down and tilted.
That is, the mirror support rod 104 and the vacuum chamber 105
Is sealed by a bellows 107. The vacuum chamber 105 is provided with beam connection bellows 111a and 111b at both ends. The beam connection bellows 111a and 111b are connected to SR-X-ray beam ducts (not shown), respectively, from the SOR ring to the irradiation chamber. The introduced SR-X-ray is guided to the vacuum chamber 105 in the middle of the path. [0016] At one end of the retainer support plate 103, position of the X-ray
An X-ray position sensor 112 , which is an X-ray detector for detecting the position, is held.
12, the direction of the displacement is the relative displacement of the beam connecting bellows 111a you pair <br/> the mirror 101 of the SR-X-ray introduced into the vacuum chamber 105 from the y-axis direction and
Detect the amount . The mirror support 106 is a driving means y.
The ball screw and the ball nut driven by the drive motor 110 reciprocate in the direction perpendicular to the reflecting surface of the mirror 101 (y-axis direction). The tilt plate 201 is integrally fixed to the housing 202,
Numeral 02 supports the mirror support 106 so as to be able to move linearly in the y-axis direction by means of a y-linear motion guide 203 which is a guide means. The tilt plate 201 is fixed to a flat hollow frame-shaped reference frame 301 by three ωxωz adjusting screws 204,
The tilt direction and tilt angle of the tilt plate 201 with respect to the reference frame 301 can be finely adjusted by the ωxωz adjusting screw 204. The reference frame 301 is supported by a pair of bearing devices 302 provided at both ends so as to be rotatable around the longitudinal axis (z-axis direction) of the mirror 101, and each bearing device 302 is an L-shaped rod. Fixed at the center of 303
Both ends of the character rod 303 are hollow frame-shaped large frame 401
Is screwed to the top. The rotation angle of the reference frame 301 around the z axis is adjusted by a cam mechanism driven by the ωz drive motor 304. After the rotation adjustment is completed, the lock screw 305 is tightened, and the reference frame 301 is rotated. Is fixed to the large frame 401. Further, a detector unit D for detecting the position of the SR-X-ray is detachably mounted on the lower surface in the z-axis direction front of the reference frame 301. The large frame 401 includes a pair of L-shaped brackets 4.
02 supports the bottom of the vacuum chamber 105.
The L-shaped fitting 402 is made of a material having a small rigidity. When the vacuum chamber 105 is reduced in pressure from a normal pressure to a vacuum atmosphere (for example, about 10 ⁻⁷ to 10 ⁻¹⁰ torr) by a vacuum pump, the deformation of the vacuum chamber 105 Absorb
This prevents distortion from occurring in the large frame 401. As can be seen from FIG. 2, the vacuum chamber 1
05 is held inside the large frame 401 by an L-shaped bracket 402 fixed to the bottom of the large frame 401,
On the other hand, the mirror 101 is supported by the mirror attitude adjusting device A including the reference frame 301 and the tilt plate 201 mounted on the top of the large frame 401 via the mirror support bar 104 and the mirror support 106. Next, the gantry structure B supporting the large frame 401 will be described. The gantry structure B includes a flat frame-shaped gantry upper 501 and a three-dimensional frame-shaped gantry lower 601.
The large frame 401 is provided with a mirror 10 along a pair of x guide rails 502a and 502b provided on a base 501.
1 can reciprocate in the horizontal axis direction (x-axis direction). The movement of the large frame 401 in the x-axis direction is performed by manually rotating the x-feed screw 503 held on the gantry 501. The upper gantry 501 is supported on the lower gantry 601 so as to be rotatable around a vertical central axis (y-axis).
The rotation angle about the axis is adjusted by a cam mechanism driven by a ωy drive motor 602, which is a third drive unit driven by a drive motor. In addition, under the frame 60
The length of each foot 603 can be adjusted, and by adjusting the length of each foot, the tilt direction and the tilt angle under the gantry, that is, the tilt of the gantry structure B and the large frame 401 with respect to the floor surface are adjusted. be able to. Further, an ion pump 701 and a NEG pump 702 disposed immediately below the vacuum chamber 105 are held inside a gantry structure B including a gantry upper 501 and a gantry lower 601. The initial positioning of the mirror adjusts the displacement
The tilt plate 201, the reference frame 301, and the large frame 40 of the above-described mirror attitude adjusting device A,
1, and the upper 501 of the gantry structure B and the lower 6 of the gantry
01 is adjusted by the method described above. During exposure, vibration, temperature change or SR-
The reflection surface of the mirror 101 and the SR
When the relative position with respect to the X-ray changes in the y-axis direction, the locking device of the mirror support 106 is released, and the y drive motor 110 is driven in accordance with the output of the X-ray position sensor 112.
Is driven to move the mirror 101 in the y-axis direction.
After the illuminance unevenness in the exposure area of the wafer is eliminated in this manner, the mirror support 10 is again locked by the lock device.
6 is fixed. The control circuit for the mirror position is shown in FIG .
U, position sensor (X-ray position sensor 11
2), a controller as a control means, which is controlled by the controller
Actuator (y drive motor 110), mirror
That having a closed loop circuit consisting of (mirror 101). When the relative position between the reflection surface of the mirror 101 and the SR-X-ray is not stable, the lock is always released and the mirror 101 is controlled to be moved to an appropriate position according to the output of the X-ray position sensor 112. Is also good. Next, the mirror support will be described in detail. As shown in FIGS. 3 and 4, the rotating shaft of the y drive motor 110 is connected to a ball screw 1002 via a coupling 1001, and the ball screw 1002 is integral with the housing 202 near both ends thereof. It is rotatably supported by a radial bearing 1003a and a thrust bearing 1003b. The central portion of the ball screw 1002 is formed with a screw portion, and is screwed to a ball nut 1004 formed in a central column of the mirror support 106. When the y drive motor 110 is started, the ball screw 1002 rotates to move the ball nut 1004 up and down. As a result, the mirror support 1 integrated with the ball nut 1004
06 moves in the y-axis direction. The housing 202 is fixed to the tilt plate 201 by four connecting plates 1005, and fine adjustment in the ωx and ωz directions is performed by the tilt plate 201. The y linear guide 203, which is a guide means for supporting the mirror support 106 so as to be able to linearly move, includes four y linear guides 20.
3 and is interposed between the housing 202 and both ends of the central columnar portion of the mirror support 106. The y-linear guide 203 has sufficient rigidity, and has a ball screw 1002
When the mirror support 106 moves in the y direction together with the ball nut 1004 due to the rotation of the ball support 1004, high-precision positioning can be performed without lateral displacement. Further, a lock device for locking the mirror support 106 to the tilt plate 201 when a new position in the y-axis direction of the mirror support 106 is set by driving the y drive motor 110 is provided. The locking device is
It comprises a rod clamp 1007, a lock rod 1008, a rod supporter 1009, and a lock bolt 1010. After the mirror support 106 is moved to a new y-axis direction position, the lock bolt 1010 is tightened to be fixed at that position. In addition, a cooling means is provided for preventing the dimensional accuracy from deteriorating due to the heat generated by the y drive motor 110. The cooling means comprises a coolant passage 1011 provided in the sliding bearing portion of the mirror support 106 and a coolant passage 1012 provided in the y-linear guide 203 of the housing. Support 106, y-linear guide 203 and housing 20
2 prevents temperature rise. Further, when the cooling means requires baking for increasing the degree of vacuum in the vacuum chamber 105 before starting the X-ray exposure,
It can also be used to prevent the y-linear guide 203 and its surrounding structure from being damaged by heat. The mirror support rod 104 held by the mirror support 106 is inserted into the vacuum chamber 105 from the opening where the bellows 107 is provided, and the holder support plate 103 for detachably holding the mirror holder 102 is a mirror. The support rod 104 is fixed to the lower end. A bellows 107 is provided between the top end of the mirror support 106 and a top plate 109 integrally connected to the vacuum chamber 105 by a wall plate 105a.
A counter bellows 108 having the same diameter or the same cross-sectional area as is provided. By reducing the pressure inside the counter bellows 108 to a vacuum with the vacuum pipe 108a, the imbalance in the pressure applied to the mirror support 106 is eliminated, and a decrease in the accuracy of the y-axis position due to fluctuations in the atmospheric pressure is prevented. Also, there is an effect of reducing the driving force of the y drive motor 110. The present invention is configured as described above, and has the following effects. During X-ray exposure, vibration, temperature change and SR-
By detecting and eliminating the relative displacement between the optical path of the X-ray and the reflecting surface of the mirror due to the fluctuation of the X-ray, uneven illuminance can be prevented and the substrate surface can be uniformly exposed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially cutaway perspective view showing one embodiment of the present invention. FIG. 2 is a side view showing a state where a detector unit and a shutter unit of the present embodiment are removed. FIG. 3 is a partial cross-sectional view showing a part of a mirror, a mirror support, and a tilt plate. FIG. 4 is a sectional view taken along the line AA ′ of FIG. 3; FIG. 5 is a block diagram of a control circuit of a mirror position. [Description of Signs] A Mirror posture adjusting device B Mount structure 101 Mirror 102 Mirror holder 103 Cage support plate 104 Mirror support rod 105 Vacuum chamber 105a Wall plate 106 Mirror support 107 Bellows 108 Counter bellows 108a Vacuum pipe 109 Top plate 110 y drive motor 112 X-ray position sensor 201 tilt plate 202 housing 203 y linear motion guide 301 reference frame 401 large frame 501 upper frame 601 lower frame

────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Takayuki Hasegawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (56) References JP-A-3-288422 (JP, A) JP-A-3 155100 (JP, A) JP-A-1-199188 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G21K 5/02 G21K 1/06

Claims (1)

(57) and the mirror support Claims The claim 1] X-ray supporting a mirror having a reflecting surface for enlarging a desired direction, vertically against the reflecting surface of the X-ray and X-ray detector for detecting a positional deviation of direction, and driving means for moving vertically the mirror support relative to the reflecting surface, the X-ray
And a control circuit for regulating the positional displacement by controlling the drive means by the output signal of the detector, vacuum Cha
The mirror is arranged in the chamber and the vacuum chamber is
The mirror support is arranged outside the member,
Opening of a vacuum chamber, the mirror and the mirror support
The bellows tightly closes the gap between the body and the connecting means.
A top plate that is sealed and is integral with the vacuum chamber
Counter bellows between the top of the mirror support
And the inside of the counter bellows is
SR characterized by being decompressed like chamber
An X-ray mirror unit.