JP3318440B2 - Stage origin position determining method and apparatus, and stage position detector origin determining method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and a device for determining the origin of a stage and to a method and an apparatus for determining the origin of a stage position detector. The present invention relates to a stage origin position determining method and apparatus for determining an origin position of an XY stage used in production, and an origin position determining method and apparatus of a stage position detector for detecting the position of the XY stage.

2. Description of the Related Art A semiconductor integrated circuit manufacturing apparatus such as an electron beam exposure apparatus, an X-ray exposure apparatus, and an optical stepper used for manufacturing a semiconductor integrated circuit or the like fixes a semiconductor wafer for manufacturing a semiconductor integrated circuit or the like and has a high precision. XY stage for performing electron beam exposure and the like by moving under the control of.

In recent years, with the miniaturization of semiconductor integrated circuits, there has been a demand for higher precision in determining the XY stage position (origin position).

[0004]

2. Description of the Related Art A conventional method of determining an origin position on an XY stage will be described with reference to FIGS.

[0007] In the description of FIGS. 9 to 12, only a portion related to the X stage will be described for simplification. For the part related to the Y stage, X
Since the configuration and operation are the same as those of the part relating to the stage, the description is omitted.

FIG. 9 is a plan view of a conventional origin position determining device. The origin position determination device 100 shown in FIG.
An X stage that moves in the X-axis direction while fixing a semiconductor wafer or the like, and an Y stage that moves in the Y axis direction while fixing a semiconductor wafer or the like
A vacuum chamber 102 containing an XY stage (not shown) including a stage, an actuator 101 having a DC (direct current) motor 117 for driving the X stage in the X-axis direction, and an origin position determining unit for determining the origin position of the X stage 103.

The origin position determination unit 103 has one end coupled to the X stage and a drive shaft 104 that moves with the movement of the X stage, and the light emitting diode 10 that emits the origin detection light.
5 to 107, photodetectors 108 to 110 for receiving the emitted origin detection light, and an origin signal detection sensor disposed on the drive shaft 104 corresponding to each origin position for detecting the origin position of the X stage. It comprises a plate 111 and slits 112 and 113.

FIG. 10 is a side view of the origin position detecting device shown in FIG. Origin signal detection sensor plate 111
The slits 112 and 113 are arranged at positions as shown in FIG. The slits 112 and 113 are provided with the light emitting diode 105 or 1.
A slit for passing the reference light 07 is provided in each of them.

FIG. 11 is an enlarged view of the origin position detecting unit 103 in FIGS. 9 and 10. 11A is a plan view, and FIG. 11B is a side view. The drive shaft 104 moves in the horizontal left and right directions in the figure as the X stage moves.

The light emitting diodes 105 and 107 emit the same amount of origin detection light 120 and 122, respectively. Also,
The origin signal detection sensor plate 111 is arranged on the drive shaft 104 so as to shield the origin detection light 121 emitted from the light emitting diode 106 when the X stage is at the origin position.

Further, when the X stage is at the origin position on the drive shaft 104, the light spot of the origin detection light 122 or 120 emitted from the light emitting diode 105 or 107 on the drive shaft 104 is shifted by the slits 112 and 113 in FIG. 114 and 115, that is, the origin detection light 1
Of the 22 or 120 light amounts, they are arranged at positions where the origin detection light corresponding to half the light amount respectively passes.

Next, the operation of the origin position detection unit 103 for detecting the origin position will be described with reference to FIGS. Detection of the origin position in the origin position detection unit 103 shown in FIG. 11, the output T _a of the photodetector 108, the difference between the output T _b of the photodetector 110 (T
_b −T _a ).

[0013] FIG. 12 is a relationship between the position and the output difference of the drive shaft 104 (T _b -T _a) is shown. The origin coordinates in FIG. 12 correspond to the position of the drive shaft when the X stage to which the drive shaft 104 is connected is at the origin position.

First, when the X stage is at the origin position, as described above, the origin detection light corresponding to half of the light amount of the origin detection light 122 or 120 passes through the slits 112 and 113 and passes through the photodetector. 108 and 110, the respective output differences (T _b −T
_a ) becomes 0 (corresponding to the origin in FIG. 12).

Here, when the drive shaft 104 moves to the right in FIG. 11 (positive direction of x in FIG. 11) with the movement of the X stage, the light amount of the origin detection light 122 passing through the slit 112 increases, Origin detection light 120 passing through 113
, The output difference (T _b −T _a ) of the corresponding photodetector becomes a negative value. Then, all of the origin detection light 122 reaches a local maximum value at the position of the drive shaft 104 (the position of x1 in FIG. 12) passing through the slit 112. Further movement to the right in FIG. 11, a portion of the origin detection light 122 is blocked by the slit 112 again, the output difference (T _b -T _a) begins to increase, the origin detection light 122 and 120, respectively slits 112 and 1
Becomes zero at the position of the drive shaft 104 together all shielding (position of x ₂ in FIG. 12) by 13.

Conversely, when the drive shaft 104 moves to the left in FIG. 11 (negative direction of x in FIG. 11) as the X stage moves, the origin detection light 120 passing through the slit 113
The amount of light increases, since the light quantity of the origin detection light 122 that passes through the slit 112 decreases, the output difference of the photodetector corresponding to each (T _b -T _a) has a positive value.
Then, all of the origin detection light 120 becomes the maximum value at the position of the drive shaft 104 that passes through the slits 113 (position of x ₃ in FIG. 12). Moving further to the left in FIG.
Since a part of the origin detection light 120 is blocked by the slit 113 again, the output difference (T _b -T _a) begins to decrease, the origin detection light 122 and 120, respectively slits 112
Becomes zero at the position of the drive shaft 104 together all shielding (position of the x ₄ in FIG. 12) and by 113.

As a result of the above operation, the difference between the position of the drive shaft 104 and the output of the photodetectors 108 and 110 (T _b −
The relationship of _Ta ) is as shown in FIG. Therefore,
Position corresponding to the origin of Fig. 12, i.e., the output difference Fotodikuta 108 and 110 (T _b -T _a) is 0, and controls the drive shaft 104 so that the position where the output of the photodetector 109 becomes 0 Then, the X stage can be set as the origin position.

[0018] In the operation of the origin position detection unit shown in FIG. 11, the drive shaft 104 is output difference even when in the position in FIG. 11 x ₂ or x ₄ (T _b -T _a) is zero But,
In this case, the origin detection light 121 of the light emitting diode 106
Since the origin signal detection sensor plate 111 is installed so that is not shielded by the origin signal detection sensor plate 111,
The output of the photodetector 109 does not become 0, and the position is not set as the origin position of the X stage.

According to the operation of the origin position detecting section 103 of the prior art described above, the origin of the XY stage can be detected with a simple circuit. Further, the XY stage according to the related art is provided with a stage position detector for measuring the position of the XY stage in accordance with the movement of the XY stage, separately from the above-mentioned origin position detecting unit.

As the stage position detector, for example, a laser interferometer is used. Usually, the laser interferometer is XY
When the stage is at the origin position determined by the operation of the origin position detection unit, the indicated value of the laser interferometer is set to indicate the origin (0, 0).

The laser interferometer is provided on each of the X stage and the Y stage. The laser interferometer guides a laser beam emitted from a laser beam emitting device provided outside the vacuum chamber 102 into the vacuum chamber, and the X stage or the Y stage. The light is reflected by a mirror that is fixedly mounted on the stage and moves with the movement of the X stage or the Y stage to obtain reflected light. Then, the reflected light is guided to the outside of the vacuum chamber 102, and is detected by a detection unit provided outside the vacuum chamber 102 to detect the position of the X stage or the Y stage.

According to the laser interferometer as the stage position detector of the prior art, the stage position can be detected with the accuracy of the wavelength level of the laser to be used, so that the position can be detected with high accuracy.

[0023]

However, the prior art stage position origin detector and stage position detector have the following problems due to their structures.

That is, the original stage position inspection of the prior art
According to the output device, the photo display near the origin in FIG.
The resolution of the detector is low,
The detector is in a common vacuum with the vacuum chamber 102
Therefore, the effect of the temperature rise of the sample in the vacuum chamber 102
The characteristics change in response to the
Was. In addition, the nonlinearity of the photodetector output
The differences between the outputs of photodetectors 108 and 110
The output difference (T _b−
T_a) May not be exactly 0.

For the above reasons, the conventional stage position origin detecting device has a first problem that the origin position cannot be determined with high accuracy. Further, a second problem is that the circuit becomes complicated because a detection circuit similar to the above is required to detect a position other than the origin.

Furthermore, since the light emitting diode, the photodetector, and the like are in the vacuum chamber 102, it is necessary to release the vacuum in order to maintain and adjust these members. Therefore, there is a third problem that the manufacturing process of the semiconductor integrated circuit is complicated and the time is long.

Further, according to the laser interferometer as the stage position detector of the prior art, if the stage rapidly moves at an acceleration equal to or higher than a predetermined acceleration, it becomes impossible to measure the position. Therefore, the moving distance during the movement of the stage at a predetermined acceleration or more cannot be measured, and an error may occur between the actual moving distance and the indicated value of the laser interferometer.

Also, since a part of the optical path of the laser beam, which is the position measuring light, is outside the vacuum chamber 102, if there is a shield that blocks the optical path of the laser beam, reflected light from the stage cannot be obtained. The position cannot be measured. Therefore,
If the stage moves while the laser beam is blocked,
An error occurred between the actual moving distance and the indicated value of the laser interferometer.

For the above reasons, the conventional stage position detector has a fourth problem that the stage position corresponding to the origin of the laser interferometer is substantially displaced.
Due to the above-described first to fourth problems of the conventional stage position origin detecting device and stage position detector, the stage position and moving distance cannot be measured with high accuracy, and accurate exposure and the like cannot be performed. There was a problem.

Therefore, the present invention has been made in view of the above-mentioned problems, and a first object of the present invention is to determine a stage position origin which can be determined with high accuracy with a simple configuration. It is to provide a method and an apparatus.

A second object is that when the stage position corresponding to the origin of the stage position detector is displaced, the stage position corresponding to the origin of the stage position detector can be accurately obtained by a simple method. A position detector origin determination method and apparatus are provided.

[0032]

In order to solve the above first and second problems, the invention according to the first aspect of the present invention is directed to a stage (one end) on which an object (24) such as a semiconductor wafer is mounted. A plane perpendicular to the moving direction of the stage (10, 11) including the optical axis of the detection light (L) of the position detector (6, 7) such as an optical displacement sensor at the other end. The detection light (L) is applied to a position detection axis (8) that includes a part of the line of intersection of the detection light (L) with a plane perpendicular to the optical axis and has a position detection plane (A) that makes a predetermined angle with the optical axis. And a stage (10, 11) such that the distance between the position detectors (6, 7) and the position detection plane (A) is measured, and the measured distance becomes a preset reference distance. Moving the distance reference stage, and when the measured distance reaches a preset reference distance.置検 Dejiku position stage of the stage corresponding to the position of (8) (10, 11) (10,
11) a stage origin position determining step to be an origin position;
Is configured.

According to a second aspect of the present invention, there is provided a stage (1) for mounting an object (24) such as a semiconductor wafer at a predetermined temporary origin position.
A first reset step of resetting a stage position detector (14, 15) such as a laser interferometer for detecting the position of (0, 11);
0, 11), an object (2) such as a semiconductor wafer
4) From the coordinate measuring step of measuring the coordinates of the specific point (60) provided on the stage by the stage position detectors (14, 15) and the first stored in advance from the measured coordinates of the specific point (60). A subtraction step of subtracting the coordinates measured by the stage position detector (14, 15) of the specific point (60) before the reset step to obtain a difference coordinate, and based on the indicated value of the stage position detector (14, 15). In a coordinate reference stage moving step of moving the stage (10, 11) to a position corresponding to the difference coordinates, and at a position of the stage (10, 11) after the coordinate reference stage moving step, a stage position detector (14, 15) a second resetting step of resetting.

According to a third aspect of the present invention, there is provided a stage position detector origin determining method according to the second aspect, in order to solve the fourth problem. Is determined as the temporary origin position.

According to a fourth aspect of the present invention, there is provided a stage origin position determining method or a stage position detector origin determining method according to the first or third aspect, in order to solve the third problem. (6, 7) is arranged in the atmosphere, the stage (10, 11) and the position detection axis (8) are arranged in a vacuum, and the detection light (L) is irradiated through the detection window (25). It is configured as follows.

According to a fifth aspect of the present invention, in order to solve the first and second problems, one end is connected to a stage (10, 11) on which an object (24) such as a semiconductor wafer is mounted. The stage (1) includes the optical axis of the detection light (L) of the position detector (6, 7) such as an optical displacement sensor at the other end.
0, 11) A position having a position detection plane (A) that includes a part of an intersection of a plane perpendicular to the movement direction of the detection light (L) and a plane perpendicular to the optical axis of the detection light (L) and forms a predetermined angle with the optical axis. Distance measuring means (19) for irradiating the detection axis (8) with detection light (L) and measuring the distance between the position detectors (6, 7) and the position detection plane (A).
A distance reference stage moving means (12, 13, 19) for moving the stage (10, 11) so that the measured distance becomes a preset reference distance; And a stage origin position determining means (19) for setting the position of the stage (10, 11) corresponding to the position of the position detection axis (8) at the time of the stage to the stage origin position of the stage (10, 11). Is done.

According to a sixth aspect of the present invention, there is provided a stage (1) for mounting an object (24) such as a semiconductor wafer at a predetermined temporary origin position.
First reset (20) means for resetting a stage position detector (14, 15) such as a laser interferometer for detecting the position of (0, 11), and on the stage (10, 11) with the temporary origin position as the origin. Coordinate measuring means (19, 2) for measuring the coordinates of a specific point (60) provided on an object (24) installed at the stage by stage position detectors (14, 15).
0, 22), storage means (19) for storing the coordinates of the specific point (60) before the reset by the first reset means detected by the stage position detectors (14, 15), and coordinate measurement means (20, 22) (6)
Subtraction means (19) for obtaining difference coordinates by subtracting the stored coordinates of the specific point (60) before the reset by the first reset means from the coordinates of (0), and the stage position detectors (14, 15). Coordinate reference stage moving means (12, 13, 19, 20) for moving the stage (10, 11) to a position corresponding to the difference coordinates based on the indicated value
And coordinate reference stage moving means (12, 13, 19, 2)
Second reset means (20) for resetting the stage position detectors (14, 15) at the positions of the stages (10, 11) after the end of the movement according to (0).

According to a seventh aspect of the present invention, in order to solve the fourth problem, in the stage position detector origin determining apparatus according to the sixth aspect, the stage origin position determining apparatus according to the fifth aspect is provided. Is determined as the temporary origin position.

According to an eighth aspect of the present invention, there is provided a stage origin position determining device or a stage position detector origin determining device according to the fifth or seventh aspect, which solves the third problem. (6, 7) is arranged in the atmosphere, the stage (10, 11) and the position detection axis (8) are arranged in a vacuum, and the detection light (L) is irradiated through the detection window (25). It is configured as follows.

[0040]

According to the first aspect of the invention, in the distance measuring step, the detection light (L) of the position detectors (6, 7) is irradiated on the position detection plane (A), and the position detectors (6, 7) are irradiated with the detection light (L). The distance between 7) and the position detection plane (A) is measured.

In the distance reference stage moving step, the stages (10, 11) are moved so that the measured distance becomes a preset reference distance. In the stage origin position determining step, the position of the stage (10, 11) corresponding to the position of the position detection axis (8) when the measured distance becomes a preset reference distance is the origin of the stage (10, 11). Position.

Therefore, the waveform of the output signal of the position detector (6, 7) becomes a waveform having the same inclination as the inclination of the position detection plane (A), and good linearity is obtained near the origin position of the stage (10, 11). , It is possible to accurately determine the stage origin position.

According to the second aspect of the present invention, in the first reset step, the stage position detectors (14, 15) for detecting the positions of the stages (10, 11) at the predetermined temporary origin positions are reset. Is done.

In the coordinate measuring step, the coordinates of the specific point (60) provided on the object (24) placed on the stage (10, 11) are determined by using the temporary origin position as the origin. 15).

In the subtraction step, the measured specific point (6
From the coordinates of (0), the stage position detector (14, 1, 1) of the specific point (60) before the first reset step stored in advance.
The difference coordinate is obtained by subtracting the coordinate measured in 5).

In the coordinate reference stage moving step, the stage (10, 11) is moved to a position corresponding to the difference coordinate based on the indicated value of the stage position detector (14, 15).

In the second reset step, the stage position detectors (14, 15) are reset at the positions of the stages (10, 11) after the end of the coordinate reference stage moving step.

Accordingly, the stage position detector (1) of the specific point (60) before the first reset step, which is stored in advance, is used.
By resetting the stage position detectors (14, 15) based on the coordinates measured by (4, 15),
Since the origin of the stage position detectors (14, 15) is reset, the position of the same stage (10, 11) can always be set as the origin of the stage position detectors (14, 15).

According to the invention described in claim 3, according to claim 1
The stage origin position determined by the stage origin position determination method described in (1) is the temporary origin position. Therefore, after the stage position detectors (14, 15) are reset near the stage origin position, the stage position detectors (14, 15)
Of the stage (10, 1, 1)
Stage position detector (14, 1) without moving 1)
5) The origin can be determined, and the stage position detector (14, 1
The origin determination operation of 5) is simplified.

According to the fifth aspect of the present invention, the distance measuring means (19) detects the light (L) detected by the position detectors (6, 7).
To the position detection plane (A), and the position detectors (6, 7)
The distance between the position and the position detection plane (A) is measured.

Distance reference stage moving means (12, 13,
19) The stage (10, 11) is moved so that the measured distance becomes a preset reference distance. The stage origin position determining means (19) determines the position of the stage (10, 11) corresponding to the position of the position detection axis (8) when the measured distance reaches a preset reference distance. ) Is the stage origin position.

Therefore, the waveform of the output signal of the position detector (6, 7) becomes a waveform having the same inclination as the inclination of the position detection plane (A), and good linearity is obtained near the origin position of the stage (10, 11). , It is possible to accurately determine the stage origin position.

According to the sixth aspect of the present invention, the first reset means (20) comprises a stage position detector (14, 15) for detecting the position of the stage (10, 11) at a predetermined temporary origin position. ) To reset.

The coordinate measuring means (19, 20, 22) calculates the coordinates of the specific point (60) provided on the object (24) placed on the stage (10, 11) with the temporary origin position as the origin. It is measured by a stage position detector (14, 15).

The storage means (19) stores the coordinates of the specific point (60) detected by the stage position detectors (14, 15) before the reset by the first reset means. The subtraction means (19) subtracts the stored coordinates of the specific point (60) before the reset by the first reset means from the coordinates of the specific point (60) measured by the coordinate measurement means (20, 22). To calculate the difference coordinates.

The coordinate reference stage moving means (12, 13,
19, 20) move the stages (10, 11) to positions corresponding to the difference coordinates based on the indication values of the stage position detectors (14, 15).

The second reset means (20) includes a stage position detector (14, 15) at the position of the stage (10, 11) after the movement by the coordinate reference stage moving means (12, 13, 19, 20). Reset.

Therefore, the stage position detectors (14, 15) are stored on the basis of the coordinates measured by the stage position detectors (14, 15) at the specific point (60) before the reset by the first reset means. By resetting, the origin of the stage position detectors (14, 15) is reset, so that the position of the same stage (10, 11) can always be set as the origin of the stage position detectors (14, 15). .

According to the invention of claim 7, according to claim 5,
The stage origin position determined by the stage origin position determination device described in (1) is a temporary origin position. Therefore, the stage position detectors (14, 15) are connected to the stages (10, 11).
Since the origin of the stage position detectors (14, 15) is determined after being reset near the origin position of the stage, the stage position detectors (14, 15) can be moved without moving the stage (10, 11) over a wide range. The origin can be determined, and the operation of determining the origin of the stage position detectors (14, 15) is simplified.

According to the invention described in claim 4 or 8, the position detectors (6, 7) are arranged in the atmosphere, and the stage (10, 11) and the position detection axis (8) are arranged in a vacuum. Then, the detection light (L) is emitted through the detection window (25).

Therefore, the position detectors (6, 7) can be adjusted and maintained without lowering the degree of vacuum in the sample chamber (1) in which the object (24) is arranged.

[0062]

Next, a preferred embodiment of the present invention will be described with reference to FIGS. The following embodiments apply the present invention to an electron beam exposure apparatus including an XY stage for performing electron beam exposure while moving and fixing the semiconductor wafer when manufacturing a semiconductor integrated circuit or the like on the semiconductor wafer. Applied. (I) Overall Configuration of Apparatus According to Embodiment of the Present Invention First, the overall configuration of an electron beam exposure apparatus according to the present invention will be described with reference to FIG.

As shown in FIG. 1, the electron beam exposure apparatus according to the present invention comprises a vacuum chamber 1 including an X stage 10 and a Y stage 11 on which a semiconductor wafer 24 is mounted, and the like.
X axis DC motor 12 for moving X stage 10
And an X-axis actuator 2 including an optical X-axis displacement sensor 6 for detecting the origin position of the X-stage 10.
An axis origin position detecting unit 4, a Y axis actuator 3 including an optical Y axis DC motor 13 for moving the Y stage 11, and a Y axis for detecting the origin position of the Y stage 11.
A Y-axis origin position detection unit 5 including an axis displacement sensor 7; an X-axis laser interferometer 14 for detecting the position of the X-stage 10 accompanying the movement; a laser oscillator for oscillating a laser for the X-axis laser interferometer 14; An X-axis laser interferometer control unit 14a including a detector for detecting the laser beam and a controller for controlling the laser beam, a Y-axis laser interferometer 15 for detecting the position of the Y stage 11 accompanying the movement, and a Y-axis laser Interferometer 15
A Y-axis laser interferometer controller 15a comprising a laser oscillator for oscillating a laser for use, a detector for detecting reflected laser light, and a controller for controlling them, and an X-axis displacement sensor 6 and a Y-axis displacement sensor 7. X stage 1 detected
The X stage 10 and the Y stage 11 are moved to predetermined positions based on the origin positions of the 0 and Y stages 11 and the positions of the X stage 10 and the Y stage 11 detected by the X axis laser interferometer 14 and the Y axis laser interferometer 15. A stage drive control unit 19 for controlling the entire apparatus in order to perform
Reset means for resetting the X-axis laser interferometer 14 and the Y-axis laser interferometer 15 via the X-axis laser interferometer controller 14a and the Y-axis laser interferometer controller 15a, and manually moving the X stage 10 and the Y stage 11 Operating unit 20 having a moving means such as a joystick for performing an operation, an electron beam emitting unit 21 for emitting an electron beam 18 for electron beam exposure, and detecting the electron beam 18 reflected by the semiconductor wafer 24 to obtain an electron beam. A scanning electron microscope (hereinafter referred to as an SEM) that visualizes the state of the surface of the semiconductor wafer 24 near the area irradiated with the electron beam 18.
e). ) 22 and a display unit 23 of the SEM.

X stage 10 contained in vacuum chamber 1
Is provided with an X-axis mirror 16 that moves with the X-stage 10 for reflecting the laser light of the X-axis laser interferometer 14 that detects the position of the X-stage 10. Similarly, the Y-axis stage 11 also has a Y-axis mirror 17 for reflecting the laser light of the Y-axis laser interferometer 15.

The X-axis laser interferometer 14 has an X-axis mirror 16
Measuring the distance from the X-axis laser interferometer 14 to the X-axis mirror 16 by detecting the laser beam reflected by the
The signal is output to the stage drive controller 19 via the X-axis laser interferometer controller 14a. Similarly, for the Y-axis laser interferometer 15, the position of the Y stage 11 is detected by detecting the laser light reflected by the Y-axis mirror 17, and the stage is detected via the Y-axis laser interferometer controller 15a. Output to the drive control unit 19.

Since a conventional laser interferometer is used, a detailed description thereof will be omitted. On the semiconductor wafer 24, a specific pattern (for example, a “+” pattern) is previously formed at a predetermined position as the specific point 60. (II) First Embodiment Next, a first embodiment corresponding to the invention described in claims 1, 3, 4, 5, 7, and 8 will be described with reference to FIGS.

In the following description, only the X stage will be described, but the same applies to the Y stage, so that the detailed description of the Y stage will be omitted. First, an origin position detecting unit according to the first embodiment will be described with reference to FIG.

FIG. 2 is a sectional view of the X-axis origin position detecting section 4 in FIG. 1. The Y-axis origin position detecting section 5 in FIG. 1 has the same configuration. As shown in FIG.
The X-axis origin position detecting unit 4 has one end connected to an X stage 10 (not shown) and the other end connected to an optical X-axis displacement sensor 6 described later.
And a predetermined angle with the optical axis of the detection light L, including a part of the intersection of a plane perpendicular to the moving direction of the X stage 10 including the optical axis of the detection light L and the plane perpendicular to the optical axis of the detection light L. An X-axis position detection axis 8 serving as a position detection plane A, an X-axis position detection axis support plate 9 that supports the X-axis position detection axis 8, and a detection light L that emits detection light L to the position detection plane A. Measure the distance and use the distance signal S
, And a transparent detection window 25 through which detection light L of the optical X-axis displacement sensor 6 passes. Further, the inside of the X-axis origin position detecting unit 4 has the same degree of vacuum as the vacuum chamber 1, and only the optical X-axis displacement sensor 6 is installed in the atmosphere.

In FIG. 2, the X-axis position detection shaft 8 moves in the horizontal direction in the figure as the X-stage 10 driven by the X-axis DC motor 12 moves. This allows
The detection light L moves on the position detection surface A which is an oblique plane forming a predetermined angle with respect to the detection light L. Therefore, the distance from the position detection surface A to the X-axis displacement sensor 6 changes linearly in accordance with the moving distance of the X stage 10, and a distance signal S corresponding to the moving distance of the X stage 10 is obtained. .

The operation of the X-axis position detecting shaft 8 is shown in FIG.
This will be described in detail with reference to FIG. In FIG. 3, FIG.
Indicates a state in which the detection light L is irradiated on the slope of the position detection surface A. In this case, with the movement of the X-axis position detection shaft 8, the distance to be measured is changed by the detection light L, so that the distance signal S _a which corresponds to the movement of the X-axis position detection shaft 8 is obtained. Here, the symbol P represents the X stage 10
Is a point irradiated with the detection light L when is at the origin position, and the measurement length Rp when the position of the point P is irradiated with the detection light L is set in advance.

When the X-axis position detection axis 8 continues to move rightward in the figure with the movement of the X stage 10 from the position shown in FIG. 3A, the X-axis position detection axis 8 shown in FIG. Is irradiated with the detection light L. In this case, since the upper surface of the X-axis position detection axis 8 is a flat surface, the distance between the X-axis position detection axis 8 and the optical X-axis displacement sensor 6 is constant, and a distance signal _Sb having a constant value is output. The Rukoto.

When the X-axis position detecting shaft 8 moves leftward in the figure with the movement of the X stage 10 from the position shown in FIG. 3A, the X-axis position detecting shaft support plate 9 shown in FIG. Is irradiated with the detection light L. In this case, since the upper surface of the X-axis position detection axis support plate 9 is flat,
The distance between the X-axis position detection shaft support plate 9 and the optical X-axis displacement sensor 6 becomes constant, and a distance signal _Sc having a constant value is output.

The above distance signal S_aOr S_cAnd X-axis position detection
FIG. 4 is a graph showing the relationship between the output shaft 8 and the moving distance.
Show. In FIG. 4, the detection light L illuminates a point P shown in FIG.
The position of the X-axis position detection axis 8 at the time of shooting is defined as the origin.
And the position when the X-axis position detection axis 8 moves to the right.
x is the positive direction. Further, the distance signal S has a measurement length R
_PDistance signal S corresponding to_pWith the origin as the origin
Negative distance signal S corresponding to fixed length, corresponding to long measurement length
The distance signal S is positive.

As shown in FIG. 4, the distance signal Sa during the time when the detection light L is applied to the position detection surface A is obtained by comparing the position detection plane A with the detection light L and the moving direction of the X-axis position detection axis 8. Therefore, the slope of the graph at this portion is determined by the angle between the position detection plane A and the detection light L.

[0075] Further, since the distance signal S _b and S _c during which the detection light L is not irradiated on the surface other than the position detecting surface A is the detection distance is constant, in distance therebetween signals S _b and S _c The value has not changed.

According to the above-described operation of the X-axis origin position detecting section 4, a distance signal S having good linearity is obtained near the origin position of the X stage 10, as can be seen from FIG.
Next, determination of the stage origin position in this embodiment will be described with reference to FIGS.

FIG. 5 is a flowchart for determining the stage origin position in this embodiment. The process shown in FIG. 5 is mainly executed by a CPU or the like included in the stage drive control unit 19.

As shown in FIG. 5, first, in step S1
In the above, it is determined whether or not the X stage is within a predetermined range.
Is determined. This determination is based on the fact that the distance signal S
Value S _uAnd lower limit S_LWithin a predetermined range determined by
This is done by determining whether To make this determination
The details of this circuit will be described later. In step S1
If it is within the predetermined range (step S1; Y
ES), and then to move the X stage 10 to the origin position
The output value of the output signal to the X-axis DC motor 12 is calculated.
(Step S2), the result is output to the X-axis DC motor 12.
Is forced. This calculation is based on the current position of the X stage 10.
(Position of the position detection axis 8) and the X signal.
Measurement distance R of detection light L when the stage is at the origin_pTo
Corresponding distance signal S_PAnd the proportional integral derivative
Control (hereinafter, PID (Proportional plus Integral plus
 Derivative) control. ). PID
According to the control, high precision suitable for the manufacture of semiconductor integrated circuits
Can be determined.

Next, in step S3, it is determined whether or not the position of the X stage 10 has reached the origin position. This determination is based on the current position of the X stage 10 (position detection axis 8
Is performed by a distance signal corresponding to the position) S and the distance signal S _p to determine whether equal.

If the position of the X stage 10 is not the origin position (step S3; NO), the process returns to step S1 to determine the origin position again. If it is the origin position (step S3; YES), the process ends.

In step S1, the value falls within a predetermined range.
If not (step S1; NO), X stage 1
The output value to be output to the X-axis DC motor 12 to move 0
It is calculated (step S4). In step S4,
U indicates the output value to the motor, k indicates the characteristics of the DC motor, etc.
Denote a predetermined gain determined by
Distance corresponding to the position of the stage 10 (the position of the position detection axis 8)
Separation signal S and distance signal S _pOrigin calculated based on the difference from
This is the amount of deviation from the position.

When the output value U to the X-axis DC motor 12 is calculated, the position of the X stage corresponds to the minus position, that is, the distance signal S higher than the predetermined upper limit value _{Su of the} distance signal S. Position (for example, the position shown in FIG. 3C)
Is determined (step S5). This determination is performed by determining whether the distance signal S shown in FIG. 4 is positive or negative.

When the position of the X stage 10 is in the minus position (step S5; YES), the X axis D calculated in step S4 to move the X stage 10 in the forward direction.
After the sign of the output value U to the C motor 12 is inverted (step S6), it is output to the X-axis DC motor 12 (step S7).

If the position of the X stage 10 is not a minus position (step S5; NO), the output value U to the X-axis DC motor 12 calculated in step S4 to move the X stage in the negative direction is set. It is output to the X-axis DC motor 12 as it is (step S7). Thereafter, the process returns to step S1 to execute the origin position determination again.

Next, in step S1, the X stage 1
A position detection circuit of the X-axis position detection axis 8 for determining whether 0 is within a predetermined range will be described with reference to FIG.

As shown in FIG. 6, the position detection circuit C includes an amplifier 30 for amplifying the distance signal S, an A / D converter 31 for A / D converting the amplified signal, and an A / D converter 31 for A / D conversion. D
A logic circuit 32 and a register 33 for sampling the converted digital signal;
And PU34, the distance signal S upper limit S _u and the lower limit value S limit for setting the _L setter 37 and the lower limit value setting unit 38
And a comparator 35 for comparing the upper limit value _Su with the distance signal S;
A comparator 36 for comparing the lower limit value S _L with the distance signal S; a signal S ⁺ indicating that the value of the distance signal S is equal to or greater than the upper limit value S _u based on the outputs of the comparators 35 and 36;
Signal indicates that the value is less than the lower limit value S _L S ^- and the distance signal S is constituted by a logic circuit 39 for outputting a signal S ₀ indicating that it is between the upper limit value S _u and the lower limit value S _L ing. These circuits are included in the stage drive control unit 19.

In step S1, the position detection circuit C
The output signal of the signal S ⁺ or signals S ^- if a is, X
The stage 10 is not within the predetermined range (Step S1; N
O), when the output signal of the position detection circuit C is the signal S _0, it is determined that the X stage 10 is within a predetermined range (Step S1; YES).

According to the first embodiment, the X stage 1
0 in response to the movement of the distance signal S _a having good linearity in the vicinity of the origin is obtained, it is possible to determine the origin position of the X stage 10 with high precision PID control based on this.

Further, since the displacement sensors 6 and 7 are arranged in the atmosphere, the adjustment of the displacement sensors 6 and 7 can be performed without lowering the degree of vacuum in the vacuum chamber 1. (III) Second Embodiment Next, a second embodiment corresponding to the second, third, sixth, and seventh aspects of the present invention will be described with reference to FIGS.

This embodiment is an example in which the invention described in claims 2, 3, 6, and 7 is applied to position determination of the stages 10 and 11 corresponding to the origins of the laser interferometers 14 and 15 shown in FIG. is there.

In this embodiment, the laser interferometers 14 and 15 are determined by resetting the laser interferometers 14 and 15 at the origin positions of the X stage 10 and the Y stage 11 at the time of initial setting (for example, when setting the semiconductor wafer 24 on the stage). The origins of the laser interferometers 14 and 15 are set, and then the X stage 10 or the Y stage 11
Or when the robot moves with an acceleration exceeding the allowable range of 15,
Even if the laser path is shifted due to a laser error generated when an obstacle blocks the optical path of the laser interferometer (the indicated value contains an error), the original X is determined based on the specific point set on the semiconductor wafer. The laser is returned to the origin of the laser interferometers 14 and 15 corresponding to the origin of the stage 10 and the Y stage 11.

In the following description, FIG. 7 is a flowchart showing the flow of processing for determining the origin of the laser interferometers 14 and 15, and FIG. 8 is an actual X stage 10 and Y based on the flowchart shown in FIG. The operation of the stage 11 and the corresponding changes in the indicated values of the laser interferometers 14 and 15 are shown. The coordinate axes in FIG. 8 are based on the origin O of the laser interferometers 14 and 15 determined at the time of the initial setting. Further, in FIG. 8, it is assumed that the position of the specific point 60 measured by the laser interferometers 14 and 15 at the time of the initial setting is the position of the designated value (1000, 1000). The indicated value at this position is
The X stage 10 and the Y stage 11 are driven such that the specific point 60 is located at the center position of the SEM screen of the display unit 23 based on the output of the laser interferometers 14 and 1 at that time.
5 is obtained by reading the instruction, and is stored in the storage unit which is a storage unit included in the stage drive control unit 19.

In the flowchart shown in FIG. 7, first, the origin positions of the X stage 10 and the Y stage 11 are determined by the method described in the first embodiment (step S1).

Now, in FIG. 8, it is assumed that the origin positions of the X stage 10 and the Y stage 11 determined in step S1 are the positions of the symbol Q. Next, at the origin position determined in step S1, the laser interferometers 14 and 15
Is reset (step S2). This reset is performed by the operation unit 20 via the laser interferometer control units 14a and 15a. Thereby, the laser interferometers 14 and 1
The indicated value of 5 is (0,
0). This reset position is the laser interferometer 1
4 and 15 are temporary origin positions.

In step S2, the laser interferometer 14
When the temporary origin positions of the laser interferometers 14 and 15 are determined, the indicated values are then changed to the indicated values at the initial setting position of the specific point 60 (in this case, based on the indicated values of the laser interferometers 14 and 15). The X stage 10 and the Y stage 11 are moved so as to have the same value as (1000, 1000)) (Step S3). This movement is executed via the stage drive control unit 19 by means such as a joystick included in the operation unit 20.

The SEM screen after the movement in step S3 is indicated by reference numeral 40 in FIG. On the SEM screen 40, although the indicated values of the laser interferometers 14 and 15 at that time are (1000, 1000),
Since the instruction value reset in step S2 includes an error of the origin due to the above-described laser error and an error due to a difference between the resolution of the displacement sensors 6 and 7 and the accuracy of the laser interferometers 14 and 15, The position of 60 is SE
A position shifted from the center of the M screen 40 by the error (FIG. 8)
At the bottom left of the screen).

Next, in step S4, the X stage 10 and the Y stage 11 are moved so that the specific point 60 is located at the center of the SEM screen while checking on the SEM screen. This movement is also executed by the joystick or the like of the operation unit 20 via the stage drive control unit 19, similarly to the movement in step S3. The SEM screen after the movement in step S4 is indicated by reference numeral 41 in FIG.

The laser interferometers 14 and 15 after the movement
Is, for example, (900, 800) (reference numeral 52 in FIG. 8). Next, in step S5, the laser interferometers 14 and 15 after the movement in step S4 are performed.
From the indicated values (900, 800), the indicated value (100) when the specific point 60 is located at the center of the SEM screen at the time of initial setting.
0, 1000) is subtracted to obtain the indicated value difference.
This processing is performed by a subtraction unit included in the stage drive control device 19. By this processing, the point Q in FIG.
And an error (difference coordinate) between the position of the origin O and the position of the origin O is obtained.

After the indicated value difference is obtained in step S5, next, in step S6, the laser interferometer 14
The X-stage 10 and the Y-stage 11 are moved so that the indicated values of and 15 indicate the indicated value difference obtained in step S5. In the case of the present embodiment, the indicated value difference is (−100,
−200), the laser interferometers 14 and 15 are moved so that the indicated values become (−100, −200). This movement is executed by means similar to steps S3 and S4. By this movement, the X stage 10 and the Y stage
The stage 11 holds the laser interferometer 1 at the time of initial setting.
It becomes the same position (origin O in FIG. 8) as the position where 4 and 15 were reset.

When the movement in step S6 is completed, the laser interferometers 14 and 15 are reset at the positions of the X stage 10 and the Y stage 11 as indicated by reference numeral 54 in FIG. 8 (step S7). Thus, the laser interferometer 1
The errors in the origin positions of 4 and 15 can be eliminated, and the indicated values of the laser interferometers 14 and 15 can be set to (0, 0) at the same positions of the X stage 10 and the Y stage 11 as in the initial setting.

Note that the position of the specific point 60 at the time of initial setting in the above description is not limited to the center of the SEM screen, but may be a position at which positioning can be performed later under the same conditions as at the time of initial setting. Anywhere.

Also, the laser interferometer 1 based on the correct origin
The timing of the position measurement of the specific point 60 by 4 and 15 is not limited to the time of the initial setting, and may be any position as long as the position is a past position before an error such as a laser error occurs.

According to the above-described second embodiment, the error such as a laser error is determined based on the indication value of the position of the specific point 60 on the semiconductor wafer in a state where the origin of the laser interferometers 14 and 15 does not include the error. Is always resolved at the same position of the X stage 10 and the Y stage 11.
4 and 15 can be reset to determine their origin.

[0104]

As described above, according to the first or fifth aspect of the present invention, the distance between the position detecting plane of the position detecting axis and the position detector is measured, and the stage is determined based on the measured distance. Is moved, and when the measured distance becomes a preset reference distance, the position is set as the origin position of the stage, so that the waveform of the output signal of the position detector has the same inclination as the inclination of the position detection plane. Waveform, which has good linearity near the origin position of the stage.
An accurate stage origin position can be determined.

According to the second or sixth aspect of the present invention, the stage position detector is reset based on the coordinates measured by the stage position detector at the specific point before the first reset, so that the stage position is reset. Since the origin of the detector is set, the same stage position can always be set as the origin of the stage position detector.

According to the third or seventh aspect of the present invention, the origin position of the stage is set as the temporary origin position. Therefore, after the stage position detector is reset near the origin position of the stage, the stage position detector is reset. Since the origin is determined, the origin of the stage position detector can be determined without moving the stage over a wide range, and the operation of determining the origin of the stage position detector is simplified.

According to the fourth or eighth aspect of the present invention, since the position detector is disposed in the atmosphere, the position detector can be adjusted without lowering the degree of vacuum in the sample chamber in which the object is disposed. Maintenance becomes possible.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall configuration of an electron beam exposure apparatus including an XY stage according to the present invention.

FIG. 2 is a diagram illustrating a partial cross section of an origin position detecting unit according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating position detection of a displacement sensor according to the first embodiment of the present invention.

FIG. 4 is a diagram showing an output waveform of a distance signal S according to the first embodiment of the present invention.

FIG. 5 is a flowchart illustrating an operation of determining an origin position based on the output of the displacement sensor according to the first embodiment of the present invention.

FIG. 6 is a diagram illustrating a configuration of a position detection circuit C according to the first embodiment of the present invention.

FIG. 7 is a flowchart illustrating an operation of an origin determination method for a stage position detector according to a second embodiment of the present invention.

FIG. 8 is a diagram for explaining the origin determination of a stage position detector according to a second embodiment of the present invention.

FIG. 9 is a diagram showing a plane of a conventional origin position determining device.

FIG. 10 is a diagram illustrating a side view of a conventional origin position determination device.

FIG. 11 is an enlarged view of an origin position detecting unit in the origin position determining device of the prior art.

FIG. 12 is a diagram showing a waveform of an output signal of an origin position detection unit in a conventional origin position determination device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Vacuum chamber 2 ... X-axis actuator 3 ... Y-axis actuator 4 ... X-axis origin position detection part 5 ... Y-axis origin position detection part 6 ... X-axis displacement sensor 7 ... Y-axis displacement sensor 8 ... X-axis position detection axis 9 ... X-axis position detection shaft support plate 10 ... X-stage 11 ... Y-stage 12 ... X-axis DC motor 13 ... Y-axis DC motor 14 ... X-axis laser interferometer 14a ... X-axis laser interferometer controller 15 ... Y-axis laser interference 15a: Y-axis laser interferometer control unit 16: X-axis mirror 17: Y-axis mirror 18: electron beam 19: stage drive control unit 20: search unit 21: electron beam emission unit 22: SEM 23: display unit 24: semiconductor Wafer 25 ... Detection window 30 ... Amplifier 31 ... A / D converter 32 ... Logic circuit 33 ... Register 34 ... CPU 35,36 ... Comparator 37 ... Upper limit value setting device 38 ... Lower limit value setting device 9 Logic circuit 40, 41 SEM screen 50-54 Laser interferometer indicated value 60 Specific point 100 Origin position determination device (conventional technology) 101 Actuator 102 Vacuum chamber 103 Origin position detection unit 104 Drive Axis 105-107 Light-emitting diode 108-110 Photodetector 111 Origin signal detection sensor plate 112, 113 Slit 114-116 Light spot 117 DC motor 120-122 Light-emitting diode output light A Position detection surface L Detection point corresponds to the origin position of the light P ... X stage _{10 S, S a, S b} , S c, S +, S -, S o ... distance signal Q ... temporary origin position O ... origin R _p ... measuring length T _a , T _B ... signal

──────────────────────────────────────────────────続 き Continuation of front page (51) Int.Cl. ⁷ Identification code FI H01L 21/68 H01L 21/30 503A 503Z (56) References JP-A-3-10105 (JP, A) JP-A-5-283313 (JP, A) JP-A-62-150721 (JP, A) JP-A-4-171163 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/027 B23Q 15 / 00 309 G01B 11/00 G03F 9/00

Claims (8)

(57) [Claims] 1. One end is connected to the stage (10, 11), and the other end includes a moving direction of the stage (10, 11) including the optical axis of the detection light (L) of the position detector (6, 7). A position detection axis (8) having a position detection plane (A) which includes a part of an intersection of a vertical plane and a plane perpendicular to the optical axis of the detection light (L) and has a predetermined angle with the optical axis. A distance measuring step of irradiating the detection light (L) and measuring a distance between the position detectors (6, 7) and the position detection plane (A); A distance reference stage moving step of moving the stage (10, 11) so that the stage (10, 11) corresponds to the position of the position detection axis (8) when the measured distance becomes a preset reference distance. The position of (10, 11) is the stage origin position of the stage (10, 11). Stage home position determination method characterized by having a stage home position determination step of a. 2. A stage (1) at a predetermined temporary origin position.
A first reset step of resetting a stage position detector (14, 15) for detecting the position of (0, 11);
1) The coordinates of a specific point (60) provided on an object (24) placed on the stage are detected by the stage position detector (14,
15) the stage position detector (14, 15) of the specific point (60) before the first reset step, which is stored in advance, from the measured coordinates of the specific point (60). ), A subtraction step of obtaining a difference coordinate by subtracting the coordinates measured by the stage (10, 10) based on an instruction of the stage position detector (14, 15).
11) a coordinate reference stage moving step of moving the stage, and a second reset step of resetting the stage position detectors (14, 15) at the positions of the stages (10, 11) after the coordinate reference stage moving step is completed. A stage position detector origin determination method, comprising: 3. The stage position detector origin determination method according to claim 2, wherein a stage origin position determined by the stage origin position determination method according to claim 1 is set as the temporary origin position. Stage position detector origin determination method. 4. The stage origin position determining method or stage position detector origin determining method according to claim 1, wherein the position detector (6, 7) is disposed in the atmosphere, and the stage (10, 11) and the position detection axis (8) are disposed in a vacuum, and the detection light (L) is emitted through a detection window (25). Origin determination method. 5. One end is connected to the stage (10, 11), and the other end includes a moving direction of the stage (10, 11) including the optical axis of the detection light (L) of the position detector (6, 7). A position detection axis (8) having a position detection plane (A) which includes a part of an intersection of a vertical plane and a plane perpendicular to the optical axis of the detection light (L) and has a predetermined angle with the optical axis. A distance measuring unit (19) for irradiating the detection light (L) and measuring a distance between the position detectors (6, 7) and the position detection plane (A); and the measured distance is set in advance. A distance reference stage moving means (12, 13, 19) for moving the stage (10, 11) so as to have a reference distance; and a position detection axis (when the measured distance becomes a preset reference distance). 8) The position of the stage (10, 11) corresponding to the position of Stage home position determining means for the stage origin position of 0, 11) (1
9) A stage origin position determining device, comprising: 6. A stage (1) at a predetermined temporary origin position.
First reset means (2) for resetting the stage position detectors (14, 15) for detecting the positions of 0, 11).
0) and the stage (10, 1
1) The coordinates of a specific point (60) provided on an object (24) placed on the stage are detected by the stage position detectors (14, 1).
Coordinate measuring means (19, 20, 22) for measuring by 5)
Storage means (19) for storing the coordinates of the specific point (60) before the reset by the first reset means detected by the stage position detectors (14, 15); and the coordinate measuring means (20, Subtraction means (1) for obtaining difference coordinates by subtracting the stored coordinates of the specific point (60) before resetting by the first reset means from the coordinates of the specific point (60) measured by (22).
9) and the stage (1) at a position corresponding to the difference coordinate based on the indication value of the stage position detector (14, 15).
(0, 11), a coordinate reference stage moving means (1)
2, 13, 19, 20) and the coordinate reference stage moving means (12, 13, 19, 2)
In the position of the stage (10, 11) after the end of the movement according to (0), the stage position detector (14, 15)
And a second reset means (20) for resetting the position of the stage position detector. 7. The stage position detector origin determination device according to claim 6, wherein a stage origin position determined by the stage origin position determination device according to claim 5 is set as the temporary origin position. Stage position detector origin determination device. 8. The stage origin position determining device or the stage position detector origin determining device according to claim 5, wherein the position detector (6, 7) is arranged in the atmosphere, and the stage (10, 11) and the position detection axis (8) are arranged in a vacuum, and the detection light (L) is emitted through a detection window (25). Origin determination device.