JPH08330219A - Scanning-type exposure device - Google Patents

Abstract

PURPOSE: To perform the exposure of a mask pattern onto a photosensitive substrate with a high throughput even when the inclination adjustment error of the light axis of a flux of illumination light or a sharp change in flatness occurs. CONSTITUTION: In a control system 12, when a mask 3 and a photosensitive substrate 4 pass through a projection region of a projection optical system 2, the output of focus sensor s 8A and 8B is monitored, a drive system 14 is controlled with a specific alignment point for adjusting focus, and then the alignment mark position of the mask 3 and the photosensitive substrate 4 is measured by an alignment sensor 7. When the mask 3 and the photosensitive substrate 4 are carried to an exposure starting position, a drive system 13 is controlled based on the detection information of the alignment sensor at a specific alignment point stored at least at a storage 11 in the control system 12 before starting exposure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning type exposure apparatus,
For example, the present invention relates to a scanning type exposure apparatus suitable for manufacturing a liquid crystal display device.

[0002]

2. Description of the Related Art Conventionally, in this type of exposure apparatus, the relative position in the in-plane direction of the mask and the photosensitive substrate (the relative position in the two-dimensional direction orthogonal to the optical axis of the projection optical system) and the projection optical system during scanning exposure. A method of detecting the position in the optical axis direction and correcting the positioning of the relative position (alignment operation) and the positioning of the optical axis direction (focus operation) simultaneously (real time) has been adopted.

However, in this method, the factors (mechanical response, precision of control system, etc.) caused by the device itself and the factors (steep change in the flatness of the mask and the photosensitive substrate itself) caused by the material are caused. Therefore, the correction operation for the input result and the detection result is delayed, and the correction operation cannot keep up with the scanning speed. In such a case, the positional relationship between the mask and the photosensitive substrate cannot always be maintained within a favorable accuracy range, and there is a possibility that the device may malfunction due to a partial reduction in resolution.

For example, the flatness of the mask or the photosensitive substrate varies in thickness, and in the photosensitive substrate, a sharp change occurs partially due to deformation due to heat treatment or foreign substances mixed in with the supporting surface. easy. Therefore, when such a change occurs, the time from the detection of the change amount to the position correction by the drive system may not be in time for the scanning speed, and the resolution may be deteriorated.

Further, when the measurement point used for detecting the correction amount must be provided outside the exposure area due to the layout and the like, the correction amount cannot be directly obtained, so that it is difficult to cope with a sharp change. There was a possibility that it might not exist

As a method for avoiding such various problems, it is conceivable to reduce the scanning speed to perform exposure, but it is unavoidable that the throughput (processing capacity) is lowered.

Under such circumstances, the applicant of the present application preliminarily measures the relative position of the mask and the photosensitive substrate in the optical axis direction during the conveyance to the exposure start position which is the outward path, and the return path is based on this result. A scanning exposure apparatus characterized by correcting the relative position of the mask and the photosensitive substrate in the optical axis direction during scanning exposure was proposed as Japanese Patent Application No. 6-114782. According to the present invention, even when the flatness changes so sharply that it cannot be predicted, the relative positional relationship between the mask and the photosensitive substrate is corrected to an almost proper positional relationship and exposure is performed with high throughput. You can

[0008]

However, in the invention of Japanese Patent Application No. 6-114782 mentioned above, measurement of the relative positional relationship between the mask and the photosensitive substrate at an arbitrary position performed during the conveyance to the exposure start position ( In the alignment measurement) operation, if there is an error (focusing error) in the relative positional relationship between the mask and the photosensitive substrate in the optical axis direction, due to this error, the alignment result also shows It was subsequently found that errors could occur.

For example, in the case of adopting the image processing alignment method, after proper focusing control, an image of a mark as shown by a shaded area a in the upper part of FIG. 5 is obtained, and the signal processing area b is obtained. Corresponding to this, the output waveform of the alignment sensor having clear rising and falling edges as shown in the middle part of FIG. 5 is obtained. However, if there is a focusing error, only an image with a focus shift as indicated by the symbol c is obtained, and correspondingly, the signal processing region b
From FIG. 5, the edge portion as shown in the lower part of FIG. 5 has a slope shape and only an unclear waveform is obtained. in this case,
The edge position of the image is detected differently depending on the shape of the slope portion of the waveform, which causes an error in the detection result of the mark position.

Irrespective of whether the laser system or the image processing system is used as the alignment method, as shown in FIG. 6, illumination in which the inclination of the optical axis is ideally adjusted as shown by the dotted arrow e. In the case of the light flux, no error occurs in the position measurement of the mark M even if there is a focusing error, but in the case of the illumination light flux having the optical axis tilt error θ as shown by the solid arrow f, A position measurement error ΔL of the mark M is generated according to the tilt error θ and the focusing error. This tilt error θ of the optical axis is not limited to the case where the adjustment is insufficient, but is often given intentionally in the non-measurement direction when using a laser beam or the like.

The present invention has been made under the above circumstances, and an object thereof is to provide a mask with high throughput even when an inclination adjustment error of an optical axis of an illumination light beam or a sharp change in flatness occurs. Another object of the present invention is to provide a scanning type exposure apparatus capable of satisfactorily exposing the pattern of (1) onto the photosensitive substrate.

[0012]

According to a first aspect of the present invention, a pattern on the mask is transferred onto the photosensitive substrate through a projection optical system while moving the mask and the photosensitive substrate in synchronization with each other in a predetermined scanning direction. A scanning exposure apparatus for sequentially transferring to,
A first detecting a relative positional relationship between the mask and the photosensitive substrate in a two-dimensional direction orthogonal to an optical axis of the projection optical system.
Position detecting means; second position detecting means for detecting a relative positional relationship between the mask and the photosensitive substrate in the optical axis direction; and the mask and the photosensitive material detected by the first position detecting means. First positional information, which is information on a relative positional relationship with a substrate in a two-dimensional direction orthogonal to the optical axis, and the second positional information.
Storage means for storing second position information, which is information on the relative positional relationship between the mask and the photosensitive substrate in the optical axis direction, detected by the position detecting means; A first adjusting means for adjusting a relative positional relationship in a two-dimensional direction orthogonal to the optical axis; and a second adjusting means for adjusting a relative positional relationship between the mask and the photosensitive substrate in the optical axis direction. Adjusting means; at a predetermined alignment point while monitoring the output of the second position detecting means when the mask and the photosensitive substrate are conveyed to the exposure start position through the projection area of the projection optical system. After controlling the second adjusting means to adjust the relative positional relationship between the mask and the photosensitive substrate with respect to the optical axis direction,
First control means for detecting a relative positional relationship between the mask and the photosensitive substrate in a two-dimensional direction orthogonal to the optical axis through the detection means; After the conveyance and before the start of exposure, the first adjusting means is controlled based on the first position information at least at a predetermined alignment point stored in the storage means to control the light of the mask and the photosensitive substrate. Second control means for adjusting the relative position in the two-dimensional direction orthogonal to the axis.

According to a second aspect of the present invention, in the scanning exposure apparatus according to the first aspect, the storage means is provided after the mask and the photosensitive substrate are conveyed to an exposure start position and before the exposure is completed. And third control means for adjusting the relative positional relationship between the mask and the photosensitive substrate with respect to the optical axis direction using the second adjustment means based on the second position information stored in. .

According to a third aspect of the present invention, in the scanning exposure apparatus according to the second aspect, the first control means controls the second adjusting means at a predetermined alignment point. The storage means stores the control amount of the second adjustment means, and the third control means stores the discontinuous second position information stored in the storage means and the second position information.
Based on the control amount of the adjusting means, a correction map representing an appropriate correction value of a relative positional relationship between the mask and the photosensitive substrate at an arbitrary position with respect to the optical axis direction is created, and the correction map is provided during exposure. The second adjusting means is controlled according to the map.

[0015]

According to the first aspect of the present invention, in the first control means, when the mask and the photosensitive substrate are conveyed to the exposure start position through the projection area of the projection optical system, the second position is set. After monitoring the output of the detection means and controlling the second adjustment means at a predetermined alignment point to adjust the relative positional relationship between the mask and the photosensitive substrate in the optical axis direction, the first detection means is used. 2 orthogonal to the optical axis of the mask and the photosensitive substrate
The relative positional relationship in the dimension direction is detected. (Here, the relative positional relationship between the mask and the photosensitive substrate with respect to the optical axis direction means a distance between the mask and the photosensitive substrate in the optical axis direction and a relative inclination with respect to the optical axis of the mask and the photosensitive substrate. And adjusting the relative positional relationship between the photosensitive substrate and the photosensitive substrate with respect to the optical axis direction means that at least one of the position of the mask and the photosensitive substrate in the optical axis direction, the inclination of the mask and the photosensitive substrate with respect to the optical axis, or both. Adjusting either one, in other words, so-called focusing operation (focus correction)
Means In the following description, these have the same meaning. ) The first and second position information detected by the first and second control means are sequentially stored in the storage means.

When the mask and the photosensitive substrate are transported to the exposure start position, the second control means sets the first position information based on the first position information at least at the predetermined alignment point stored in the storage means before starting the exposure. The first adjusting means is controlled to adjust the relative positions of the mask and the photosensitive substrate in the two-dimensional direction orthogonal to the optical axis. As a result, the mask and the photosensitive substrate are aligned based on the first position information measured in the in-focus state. Therefore, as the alignment method, “a configuration by image processing using an image sensor such as CCD” is used.
Also, no matter how the "configuration using a laser beam or the like" is adopted, occurrence of a measurement error caused by a focusing error (focus shift) or an inclination error of the illumination light beam is prevented, and a good alignment result is obtained. be able to.

According to the second aspect of the invention, after the mask and the photosensitive substrate are conveyed to the exposure start position and before the end of the exposure, the third control means stores the first information stored in the storage means. The second adjusting means is controlled based on the position information of No. 2 to adjust the relative positional relationship between the mask and the photosensitive substrate in the optical axis direction. In this case, the third control means may globally adjust the relative positional relationship between the mask and the photosensitive substrate with respect to the optical axis direction at the exposure start position, or, during the exposure, the light of the mask and the photosensitive substrate may be adjusted. The relative positional relationship with respect to the axial direction may be sequentially adjusted.

According to the third aspect of the invention, in the first control means, when the mask and the photosensitive substrate are conveyed to the exposure start position through the projection area of the projection optical system, the second position is set. While controlling the output of the detection means, the second adjustment means is controlled at a predetermined alignment point to adjust the relative positional relationship between the mask and the photosensitive substrate in the optical axis direction, and at the same time, the second adjustment is made in the storage means. After storing the control amount of the means, the first detecting means is used to detect the relative positional relationship between the mask and the photosensitive substrate in the two-dimensional direction orthogonal to the optical axis.
In this case, if there are a plurality of alignment points, the above operation by the first control means is repeated for each alignment point. The first and second position information detected by the first and second position detecting means are sequentially stored in the storage means.

In this way, when the mask and the photosensitive substrate are conveyed to the exposure start position, before the exposure starts, the second control means at least the first position at the predetermined alignment point stored in the storage means. 1st based on information
The adjusting means is controlled to adjust the relative positions of the mask and the photosensitive substrate in the two-dimensional direction orthogonal to the optical axis.

When the mask and the photosensitive substrate are conveyed to the exposure start position, the third control means is based on the discontinuous second position information stored in the storage means and the control amount of the second adjusting means. A correction map that represents an appropriate correction value for the relative positional relationship between the mask and the photosensitive substrate in the optical axis direction at an arbitrary position is created, and the second adjusting means is controlled during exposure according to the correction map. As a result, the relative positional relationship of the mask and the photosensitive substrate with respect to the optical axis direction is sequentially adjusted according to the correction map.

According to this, even if at least one of the mask and the photosensitive substrate is moved in the direction of the optical axis in accordance with the focus control, and the measurement reference up to immediately before is changed and the measurement result becomes discontinuous, the result is single. Since the correction map converted into the continuous measurement result based on the reference is created before the exposure is started, the focus control accuracy during the scanning exposure does not deteriorate.

From this point of view, the second position detecting means for detecting the relative position of the mask and the photosensitive substrate in the optical axis direction, individually measures and stores the positions of the mask and the photosensitive substrate, and calculates the result. It is desirable to use a method that calculates the relative distance between the two.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 schematically shows the structure of a scanning type exposure apparatus 1 according to one embodiment. The scanning exposure apparatus 1 includes two projection optical systems (or imaging optical systems) 2A,
The mask 3 and the photosensitive substrate 4, which are arranged on the carriage 5 so as to face each other with the projection optical system 2 (see FIGS. 2 and 3) composed of 2B sandwiched from above and below, are synchronized in the horizontal direction (X direction) of the paper surface. In this system, the original image pattern formed (or drawn) on the mask 3 by scanning is projected and exposed on the photosensitive substrate 4.

Here, each of the two projection optical systems 2A and 2B is composed of a plurality of projection optical systems arranged at predetermined intervals in the Y direction (direction orthogonal to the paper surface) of FIG. The optical system and the projection optical system forming the projection optical system 2B are arranged so as to be displaced by a predetermined dimension in the Y direction. That is, the images projected onto the photosensitive substrate 4 via all the projection optical systems have a so-called staggered arrangement, and the Y-direction ends of adjacent images in other columns are mutually aligned along the X-direction. It will be arranged so that it overlaps. As a result, the projections of the projection optical system 2A (or 2B) that are projected by the projection optical system that configures the projection optical system 2B (or 2A) have a certain time difference between the Y-direction ends of the projection regions. The Y-direction end portion of each projection region projected by the optical system is overlapped and exposed, and as a result, a large area in the Y-direction can be exposed by one scan.

In the case of this scanning type exposure apparatus 1, the transport system (not shown) for transporting the mask 3 and the photosensitive substrate 4 to the holders 3A and 4A is not on both sides of the projection optical system 2 along the X direction but only on one side. It is arranged. That is, after the mask 3 and the photosensitive substrate 4 are placed on the holders 3A and 4A and the exposure is completed, it is necessary to move the carriage 5 again to the position of the transport system in order to replace the photosensitive substrate and the like. In this scanning type exposure apparatus 1, the carriage 5 is scanned from the transport system provided at a position deviated from the projection optical system 2 to the exposure start position through the position (projection area) of the projection optical system 2. In the interval (forward scan period), the relative positional relationship between the mask 3 and the photosensitive substrate 4 is measured, and the mask 3 is measured based on the measurement result.
And the photosensitive substrate 4 are aligned relative to each other in a two-dimensional direction orthogonal to the optical axis of the projection optical system, and when scanning (reverse scanning) in the opposite direction, the relative position and inclination of the mask and the photosensitive substrate with respect to the optical axis direction. The pattern formed on the mask 3 is projected and exposed on the photosensitive substrate 4 while the adjustment (focus correction) is performed.

As described above, the scanning type exposure apparatus 1 of this embodiment
Then, the detection period of the relative positional relationship is provided at the time of forward scanning, which is an essential scanning period, and the relative positional relationship between the mask 3 and the photosensitive substrate 4 is detected during this period. Without reducing the mask 3
Also, it is possible to follow a sharp change in the flatness of the photosensitive substrate 4.

Here, each component of the scanning exposure apparatus 1 will be described in more detail.

The mask 3 and the photosensitive substrate 4 have a carriage 5 having a U-shaped cross section through holders 3A and 4A, respectively.
Attached to. This carriage 5 has rails 6A
It is mounted on the main body 6 so as to be movable along it, and by the movement of the carriage 5, the synchronous scanning of the mask 3 and the photosensitive substrate 4 is realized.

Projection optical system 2A, 2 above the carriage 5.
An illumination optical system 6B is arranged at a position corresponding to B, and the illumination optical system 6B is connected to the main body 6 via a holding member (not shown).
Held in. The original image pattern formed (or drawn) on the mask 3 is illuminated by the illumination light emitted from the illumination optical system 6B.

In this embodiment, first position detecting means and second position detecting means for accurately aligning the mask 3 and the photosensitive substrate 4 are provided.

The first position detecting means is an alignment sensor 7 used for measuring the relative position of the mask 3 and the photosensitive substrate 4 in the XY two-dimensional directions (two-dimensional directions orthogonal to the optical axis of the projection optical system). It is composed of an alignment detection system 9 which processes a detection signal of the alignment sensor 7.
The alignment sensor 7 is fixed to the main body 6 together with the projection optical system 2, and is a relative position measurement mark (hereinafter referred to as “alignment mark”) arranged at an arbitrary position in the scanning direction (X direction) of the mask 3 and the photosensitive substrate 4. In this embodiment, a CCD camera is used as a main component and an image signal of an image pickup screen is output. The image signal output from the alignment sensor 7 is processed by the alignment detection system 9 and the mask 3
And the positional relationship (positional deviation) of the alignment marks formed on the photosensitive substrate 4 are detected.

The second position detecting means is a focus sensor 8 (FIG. 2) used to measure the relative positions of the mask 3 and the photosensitive substrate 4 in the Z-axis direction (the optical axis direction of the projection optical system).
(See (A)) and a focus detection system 10 that processes the detection signal of the focus sensor 8.
The focus sensor 8 is composed of two optical elements, a light emitting element 8A and a light receiving element 8B, and irradiates the surface of the mask 3 and the photosensitive substrate 4 with the illumination light in the shape of a slit emitted from the light emitting element 8A. Then, the slit image formed on each surface is re-imaged on the light receiving element 8B, and a defocus signal corresponding to the re-imaging position of each image is output. The focus detection system 10 is adapted to detect the amount of positional deviation of the mask 3 and the photosensitive substrate 4 from the reference point in the optical axis direction based on this defocus signal.

In this embodiment, the focus sensor 8 is Y
There are several along the axial direction. The plurality of focus sensors 8 are arranged so that the straight line connecting the detection points of the focus sensor 8 is sandwiched by the two straight lines connecting the projection areas of the projection optical systems 2A and 2B.

A storage device 11 as storage means is provided at the output stage of the detection systems 9 and 10. This storage device 1
A storage medium such as a fixed disk is provided in 1.
The detection results obtained by the alignment sensor 7 and the focus sensor 8 at each measurement point, that is, the first position information S1,
The second position information S2 is stored.

In this embodiment, a control system 12 is provided as a control means for finely adjusting the holders 3A and 4A based on the position information stored in the storage device 11 and controlling the movement of the carriage 5. In the present embodiment, the control system 12 also has a function of creating a correction map, which will be described later, based on the second position information S2, which is the detection result in the optical axis direction, and storing it in the storage device 11. There is.

The drive system 13 moves the holder 3A to X, Y, θ.
It is configured to be finely driven in the (rotation around the Z axis) direction, and the drive system 14 is also configured to finely drive the holder 4A in the X, Y, and Z directions and also to adjust the inclination with respect to the Z axis. . Further, the drive system 15 drives the carriage 5 in the scanning direction (X direction). Therefore, the control system 12 aligns the mask 3 and the photosensitive substrate 4 via the drive systems 13 and 14, and corrects the focus and leveling via the control system 14.

Next, an example of a series of scanning exposure operations by the scanning type exposure apparatus 1 of the present embodiment configured as described above will be described with reference to FIGS. 2 and 3.

First, at the time of initial setting, the carriage 5 is shown in FIG.
As shown in (A), it is stopped at a position outside the projection optical system 2. When the mask 3 and the photosensitive substrate 4 are attached to the holders 3A and 4A of the carriage 5 stopped at this position by the transport system, the control system 12 controls the drive system 15 to move the carriage 5 to the exposure start position. Transport is started. The carrying direction at this time is the direction indicated by the thick arrow in FIGS. 2B and 2C. By the movement of the carriage 5, the mask 3 and the photosensitive substrate 4 are synchronously scanned.

During this forward scan, the control system 12 causes the mask 3 and the photosensitive substrate 4 to move in the optical axis direction at predetermined measurement intervals or positions with respect to the scanning direction which are preset in the storage device 11 based on the stored contents. The interval of is measured one by one using the focus sensor 8. Similarly, the carriage 5 is temporarily stopped via the drive system 15 at a preset arbitrary number of alignment mark positions (alignment points), and position information from the detection system 10 at each position (particularly in the vicinity of the alignment mark). After the drive system 14 is controlled based on the sensor output) to appropriately set the relative distance and the inclination of the mask 3 and the photosensitive substrate 4 in the optical axis direction (that is, focus adjustment), the alignment sensor 7 is used to set the mask 3 and the photosensitive substrate. The relative positional deviation of 4 is measured. In this way, by performing the alignment process after the focusing operation (focus adjustment), even if there is an inclination error in the optical axis of the illumination light flux, it is not affected by this and alignment measurement is performed in an optimum state. You can After the alignment measurement is completed, the control system 12 drives the carriage 5 again via the drive system 15 while maintaining the position and inclination of the photosensitive substrate 4 in the optical axis direction, and thereafter repeats the above processing according to the setting. In this way, by performing the focusing operation at each alignment position prior to the alignment measurement, the position of the holder 4A holding the photosensitive substrate 4 is changed. There is a problem that the standard of the measurement result of the (axial distance) changes and the measurement result becomes discontinuous with the subsequent measurement results. However, in the present embodiment, this measurement result becomes discontinuous due to an original device. It eliminates the inconvenience caused by. This will be described later in detail.

Upon completion of the above-described measurement of the interval in the optical axis direction and the alignment mark position, the control system 12 exposes the mask pattern on the photosensitive substrate 4 by scanning in the opposite direction (return scanning). As shown in FIG. 3D, the carriage 5 is stopped via the drive system 15 at a position where the mask 3 and the photosensitive substrate 4 are completely separated from the projection optical system 2.

At the same time, the control system 12 obtains information on the relative positional relationship between the mask 3 and the photosensitive substrate 4 in the XY two-dimensional directions, which is obtained by measuring a plurality of alignment marks and is stored in the storage device 11. Each element such as shift, rotation, magnification, orthogonality (inclination of an axis perpendicular to the scanning direction) is derived from the position information of 1 by a method using a least square method, and the control signal is supplied to the drive system 13 based on these elements. To correct the installation position of the holder 3A and correct the positional deviation of the mask 3 with respect to the photosensitive substrate 4 (alignment is performed).

At this time, the control system 12 also includes a magnification adjusting mechanism (not shown) provided in the projection optical system 2 and an image shifter mechanism (not shown) for adjusting the transfer position of the transferred image. Then, the orthogonality of the magnification and the arrangement of the transferred image to the scanning direction is also corrected.

Further, in the present embodiment, in the state where the carriage 5 is stopped at this exposure start position, the control system 12
Based on the second position information which is the measurement result of the plurality of focus sensors 8 stored in the storage device 11, the relative positional relationship between the mask 3 and the photosensitive substrate 4 at an arbitrary position with respect to the optical axis direction is appropriate. Create a correction map that represents different correction values.

Here, regarding the creation of this correction map,
A visual description will be given with reference to FIG.

As a premise, it is assumed that the measurement by the focus sensor 8 is started with the holder 4A holding the photosensitive substrate 4 set in the neutral position of the drive system 14. FIG.
In (A), the vertical axis represents “the amount of displacement of the mask 3 and the photosensitive substrate 4 (sensor output) from an appropriate interval in the optical axis direction”, and the horizontal axis represents “the mask 3 that passes through the projection area during conveyance. The position of the photosensitive substrate 4 "is set to the same coordinate system with the transfer position with respect to the transport system and the scanning exposure start position as the starting point A and the ending point E, respectively.

Further, in order to simplify the explanation,
The photosensitive substrate 4 having sinusoidal unevenness as shown in the upper part (initial state) of FIG.
A description will be given by taking as an example a mask 3 having sinusoidal irregularities that are offset by 0 degree.

The measurement by the focus sensor 8 should be performed as continuously as possible, and the alignment measurement for measuring the relative positional relationship between the mask 3 and the photosensitive substrate 4 in the XY plane at points B and D in the figure. And

In the section until reaching point B, which is the first alignment position (section from A to B), the sensor output indicating the position of the photosensitive substrate 4 in the optical axis direction is shown in the upper part of FIG. The state changes as indicated by the dotted line g.

At the point B, which is the first alignment position, the focusing operation is performed before the alignment measurement. Therefore, the photosensitive substrate 4 is set so that the distance between the mask 3 and the photosensitive substrate 4 becomes a predetermined value (design value). The position of the holding holder 4A is moved. As a result, as shown in the middle part of FIG. 4A, the sensor output indicating the position of the photosensitive substrate 4 in the optical axis direction (shown by a dotted line g ′) indicates the sensor indicating the position of the mask 3 in the optical axis direction. It matches the output (indicated by the solid line h). At this time, the control system 12 stores in the storage device 11 the control amount of the drive system 14 corresponding to the first movement amount (the movement amount in the optical axis direction (vertical direction) and the inclination amount) represented by the symbol α. Remember.

After the alignment measurement at the first alignment position is completed (B → D section), the mask 3
And the relative distance between the photosensitive substrate 4 is measured, and the sensor output g ′ as shown in the middle part of FIG. 4A is recorded.

At point D, which is the second alignment position, as in the first alignment position, since the focusing operation is performed, as shown in the lower part of FIG. 4A,
The sensor output indicating the position of the photosensitive substrate 4 in the optical axis direction (shown by the dotted line g ″) matches the sensor output indicating the position of the mask 3 in the optical axis direction (shown by the solid line h).
At this time, in the control system 12, the second symbol represented by the symbol β is typically used.
Movement amount (movement amount in the optical axis direction (vertical direction) and tilt amount)
The control amount of the drive system 14 corresponding to is stored in the storage device 11.

After completion of the alignment measurement at the second alignment position (section D → E), the mask 3 is again displayed.
And the relative distance between the photosensitive substrate 4 is measured, and the sensor output g ″ as shown in the lower part of FIG. 4A is recorded.

When a series of these sensor outputs is arranged, it becomes as shown in FIG. 7B, and the sensor output (g) on the side of the photosensitive substrate 4 which is discontinuous with respect to the sensor output (h) on the mask 3 side. , G ′, g ″). At the time when the forward scan is completed, the sensor output as shown in FIG. 4B is stored in the storage device 11 as a data map.

Therefore, in the control system 12, of the data maps stored in the storage device 11, the sensor output data map showing the position of the photosensitive substrate 4 in the optical axis direction is used as the first and second movement amounts. By making corrections using the control amounts of the drive system 14 corresponding to α and β, a correction map of the position of the photosensitive substrate 4 in the optical axis direction composed of continuous data as shown in FIG.

When the preparation of this correction map is completed, the control system 12 starts scanning the carriage 5 in the direction indicated by the thick arrow, as shown in FIG. The image of the formed pattern is sequentially projected and exposed on the photosensitive substrate 4. During this exposure, the distance between the mask 3 and the photosensitive substrate 4 in the optical axis direction and / or the inclination angle with respect to the optical axis is sequentially corrected based on the correction map. In addition,
The tilt angle may be a direction along the scanning direction or a direction orthogonal to the scanning direction. In addition to this, by using the measurement value of the focus sensor 8 obtained during the exposure, the control according to the correction map can be performed more reliably.

When the carriage 5 has finished scanning to the position of the transport system, the control system 12 stops the carriage 5 and
The mask 3 and the photosensitive substrate 4 currently attached to the holders 3A and 4A are replaced with the mask 3 and the photosensitive substrate 4 to be exposed next. The above operation is one cycle of the exposure operation.

As described above, according to this embodiment,
When the alignment mark position between the mask 3 and the photosensitive substrate 4 is measured during forward scanning of the carriage 5, focus adjustment is performed prior to this, so that even if there is a tilt error of the optical axis of the illumination light, it is accurate. It is possible to perform accurate alignment measurement, whereby the mask 3 and the photosensitive substrate 4 at the exposure start position can be accurately aligned using the least square method or the like, and the photosensitive substrate 4 and the photosensitive substrate 4 can be aligned during scanning exposure. When correcting the interval of the mask 3 in the optical axis direction and the inclination with respect to the optical axis,
Prior to this, the necessary data is pre-loaded and the correction map is created, so that the photosensitive substrate 4 is always appropriate for the mask 3 even if the mask 3 and the photosensitive substrate 4 have steep irregularities. It is possible to control the position so that it is possible to perform exposure without defective imaging. Further, in this case, since complicated calculation processing is not required during scanning exposure, the scanning speed at the time of exposure can be increased. Therefore, the throughput can be improved as compared with the conventional one,
Further, it is possible to perform exposure without fear of deterioration of resolution.

Further, in this embodiment, as the second detecting means for detecting the relative position of the mask 3 and the photosensitive substrate 4 in the optical axis direction, the positions of the mask 3 and the photosensitive substrate 4 are individually measured and stored, Since a method of calculating the relative distance between the two by adopting this result is adopted, the movement of at least one of the mask 3 and the photosensitive substrate 4 in the optical axis direction accompanying the focus control is performed until immediately before. Even if the measurement standard is changed and the measurement result becomes discontinuous, the discontinuous measurement result can be obtained based on the movement amount (correction amount) of the mask 3 and / or the photosensitive substrate 4 in the optical axis direction. By performing the correction, it is possible to convert the result into a continuous result based on a single reference, so that the focus control accuracy during scanning exposure does not deteriorate.

As is clear from the above description, in this embodiment, the drive system 13 constitutes the first adjusting means, the drive system 14 constitutes the second adjusting means, and the control system 12 constitutes the first adjusting means. Second and third control means are configured.

Although a pair of sensor outputs are described in the above embodiment, even when a plurality of sensor outputs are arranged, similarly, discontinuous outputs can be easily obtained from the first and second movement amounts and the sensor arrangement. Can be converted to a continuous output.

In the description using FIG. 4 in the above embodiment, the case where two alignment positions are assumed has been described, but the present invention is not limited to this, and movement at each position is possible. It goes without saying that by storing the amount, an arbitrary number of alignment positions can be set regardless of the size of the set number of places.

In the above embodiment, the case has been described in which the distance between the mask 3 and the photosensitive substrate 4 in the optical axis direction and / or the inclination angle with respect to the optical axis are sequentially corrected during the exposure in the backward scan. Since each projection optical system forming the projection optical system 2 has a focus height and a range (depth of focus) at which an optimum resolving power can be obtained, the control system 12 takes these into consideration, and the control system 12 takes the mask 3 and the photosensitive substrate 4 into consideration. The distance and the inclination in the optical axis direction may be corrected at the exposure start position so that both and are set within the depth of focus. In this case, the control system 12 creates an approximate surface such that both the mask 3 and the photosensitive substrate 4 are set within the depth of focus, using the mask 3 as a reference surface, and includes the correction map (or the sensor output on the mask side). Based on the data map, the focus height of the photosensitive substrate 4 (or the mask 3) and the inclination of the surface of the area including all the projection areas of the plurality of projection optical systems are derived by the least square method or the like, and the inclination of the photosensitive substrate 4 is approximated. The drive system 14 is controlled so as to coincide with the surface.

In this case, since the relative positional relationship between the mask 3 and the photosensitive substrate 4 is corrected to the optimum condition by the above correction processing, the position and inclination of the mask 3 and the photosensitive substrate 4 in the optical axis direction are corrected. Even if scanning exposure is carried out while the image is held, there is almost no risk of defective imaging.

In the above embodiment, even if the position of the mask 3 is fixed and the height of the photosensitive substrate 4 is sequentially corrected during correction during scanning exposure, the photosensitive substrate 4 is fixed and the mask is fixed. No. 3 side may be corrected, or the mask 3 and the photosensitive substrate 4 may be corrected at the same time. In either case, exposure can be performed without fear of deterioration of resolution.

In the above embodiment, the projection optical system is set to 2
However, the present invention is not limited to this, and is widely applied to a scanning exposure apparatus that uses only one or one projection optical system and a scanning exposure apparatus that uses three or more projection optical systems. You can In either case, it is possible to realize scanning exposure with higher throughput and less resolution deterioration than in the past.

Further, in the above-mentioned embodiment, the case where the alignment sensor 7 is constituted by the CCD camera is illustrated, but the present invention is not limited to this, and instead, a laser interference type alignment sensor is used. May be used, and even in such a case, even if there is a tilt error in the optical axis of the illumination light, accurate alignment measurement can be performed without being affected by this.

In the above embodiment, when position information in the optical axis direction is measured without passing through the projection optical system 2A, 2B,
That is, the case where the measurement position is provided in the vicinity of the exposure region has been described, but the present invention is not limited to this, and the projection optical system 2A, 2
It can also be applied to the case of measuring the position in the optical axis direction via B, that is, the case of providing the measurement position in the exposure area. In this case, since the position information within the exposure amount area can be obtained as a measured value, the correction accuracy can be further improved.

In the exposure process which does not require the alignment operation, when the mask 3 and the photosensitive substrate 4 are transported to the exposure start position, the transport system is not stopped and the mask and the photosensitive substrate are moved relative to each other in the optical axis direction. Of different positions (intervals) and storage device 1
Only the memory of 1 is required.

[0070]

As described above, according to the present invention,
Even if there is an error in the tilt adjustment of the optical axis of the illumination light flux or a sharp change in flatness occurs, the mask pattern can be satisfactorily exposed on the photosensitive substrate while maintaining high throughput, which is an outstanding effect. There is.

In particular, according to the third aspect of the invention, there is an advantage that the accuracy of focusing control during scanning exposure does not deteriorate.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a configuration of a scanning exposure apparatus according to an embodiment.

FIG. 2 is an operation explanatory diagram of a carriage of the apparatus of FIG. 1 during forward scanning.

FIG. 3 is an operation explanatory view of the carriage of the apparatus of FIG. 1 during backward scanning.

FIG. 4 is a diagram for explaining an operation of creating a correction map by a control system.

FIG. 5 is a diagram for explaining a problem to be solved by the invention, and is a diagram visually showing an influence of a focus shift on alignment measurement.

FIG. 6 is a diagram for explaining a problem to be solved by the present invention, and is a diagram visually showing an influence of an inclination error of an optical axis of an illumination light flux on alignment measurement.

[Explanation of symbols]

1 Scanning Exposure Device 2 Projection Optical System 3 Mask 4 Photosensitive Substrate 7 Alignment Sensor (Part of First Position Detection Means) 8 Focus Sensor (Part of Second Position Detection Means) 9 Alignment Detection System (First Part of position detection means 10 Focus detection system (part of second position detection means) 11 Storage device (storage means) 12 Control system (first control means, second control means, third)
Control means) 13 drive system (first adjusting means) 14 drive system (second adjusting means)

Claims (3)

[Claims] 1. A scanning type exposure apparatus which sequentially transfers a pattern on the mask onto the photosensitive substrate via a projection optical system while moving the mask and the photosensitive substrate in synchronization with each other in a predetermined scanning direction, wherein: A first detecting relative positional relationship between the mask and the photosensitive substrate in a two-dimensional direction orthogonal to the optical axis of the projection optical system.
Position detecting means; second position detecting means for detecting a relative positional relationship between the mask and the photosensitive substrate in the optical axis direction; and the mask and the photosensitive material detected by the first position detecting means. First positional information, which is information on a relative positional relationship with a substrate in a two-dimensional direction orthogonal to the optical axis, and the second positional information.
Storage means for storing second position information, which is information on the relative positional relationship between the mask and the photosensitive substrate in the optical axis direction, detected by the position detecting means; A first adjusting means for adjusting a relative positional relationship in a two-dimensional direction orthogonal to the optical axis; and a second adjusting means for adjusting a relative positional relationship between the mask and the photosensitive substrate in the optical axis direction. Adjusting means; at a predetermined alignment point while monitoring the output of the second position detecting means when the mask and the photosensitive substrate are conveyed to the exposure start position through the projection area of the projection optical system. After controlling the second adjusting means to adjust the relative positional relationship between the mask and the photosensitive substrate with respect to the optical axis direction,
First control means for detecting a relative positional relationship between the mask and the photosensitive substrate in a two-dimensional direction orthogonal to the optical axis through the detection means; After the conveyance and before the start of exposure, the first adjusting means is controlled based on the first position information at least at the predetermined alignment point stored in the storage means to control the light of the mask and the photosensitive substrate. A scanning exposure apparatus having a second control means for adjusting a relative position in a two-dimensional direction orthogonal to the axis. 2. The second adjusting means is controlled based on second position information stored in the storage means after the mask and the photosensitive substrate are conveyed to an exposure start position and before the exposure is completed. The scanning exposure apparatus according to claim 1, further comprising third control means for controlling the relative positional relationship between the mask and the photosensitive substrate with respect to the optical axis direction. 3. The first control means stores a control amount of the second adjustment means in the storage means when the second adjustment means is controlled at a predetermined alignment point, and the first control means stores the control amount of the second adjustment means. The control means of No. 3 is based on the discontinuous second position information stored in the storage means and the control amount of the second adjusting means, and the light of the mask and the photosensitive substrate at an arbitrary position. The scanning type according to claim 2, wherein a correction map representing an appropriate correction value of a relative positional relationship with respect to the axial direction is created, and the second adjusting means is controlled according to the correction map during exposure. Exposure equipment.