JPH1050593A - Projection aligner and manufacture of semiconductor device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a light beam reflected from a reflective surface for a short time at a high accuracy by receiving the light beam through a projection optical system and reference mark with driving a movable stage in the reflective surface inclining direction to obtain an image formed position information, using signals from a photo-detecting element. SOLUTION: A reference mark 50 is placed on a reticle surface 1 or at a position equivalent to the reticle surface, and an inclined reflective surface 12 is placed on a wafer stage 5. The image from the mark 50 is projected on the inclined reflective surface 12 and reflected beam from this surface 12 is guided to a photo-detecting element 103 through the mark 50. The stage 5 with the inclined surface 12 is continuously scanned horizontally in the inclined direction to determine the best image formed plane position of the mark 50 by a focus position detection control means 1100, using signals from the element 103 to calculate the best image formed plane position of an exposure region.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection exposure apparatus and a method of manufacturing a device using the same, for example, a semiconductor device such as an IC or LSI, an imaging device such as a CCD, a display device such as a liquid crystal panel, a magnetic head, and the like. In a process of manufacturing a device, a pattern on a first object surface such as a reticle is projected by a projection exposure apparatus or a scanning projection exposure apparatus used in a lithography step.
This is suitable for performing positioning (focusing) in the optical axis direction of the wafer when projecting onto the object plane by the projection optical system.

[0002]

2. Description of the Related Art Conventionally, when manufacturing a semiconductor device through a process of projecting a pattern on a reticle surface onto a wafer surface by a projection optical system, a wafer is accurately positioned on an image forming surface of the projection optical system. It is important.

A method of detecting an image plane position for positioning a wafer at an image forming position of a projection optical system is disclosed in, for example, JP-A-57-212.
No. 406 proposes this.

In the method of detecting an image plane position disclosed in the publication, a slit or a pinhole is transmitted on a transfer object (reticle) having a circuit pattern set at an object position of a projection lens (projection optical system). Marks are installed. 3
An object to be transferred (wafer) is set near an imaging position on a stage (XYZ stage) movable in a dimension direction. Then, a light beam having the same wavelength as the exposure light is incident on the reticle. The light beam transmitted through the slit or pinhole on the reticle is reflected on the wafer after passing through the projection lens, and transmitted through the projection lens in the opposite direction to re-image on the slit or pinhole on the reticle. .

At this time, the amount of light transmitted through the slit or the pinhole and detected by the photodetector becomes largest when the wafer (reflection surface) is arranged at the best focus position (focus position). However, if the position of the wafer deviates from the focus position on the optical axis, the re-imaged image becomes unclear and the image spreads (blurs), so the light flux emitted by the slit or pinhole increases, and the amount of transmitted light decreases, so that light detection The amount of light detected by the detector decreases. Based on such a phenomenon, the imaging position is detected by moving the stage up and down to a position where the amount of light becomes the largest, that is, the focus position is adjusted. At this time, when a reflecting surface is used instead of the wafer, the stage is driven by correcting the difference between the upper surface of the reflecting surface and the wafer, or a focus position detecting device provided independently of the present device, for example, an oblique By using a gap sensor using an incident optical system, the position of the reflection surface is adjusted by moving the stage up and down on the surface of the wafer.

[0006]

The method of detecting the position of the imaging plane of the projection optical system proposed in the publication, that is, in the focus detection, a stage provided with a reflecting surface for performing one focus measurement is mounted on an optical axis. There is a drawback in that it has to be moved many times in the direction, which takes time and lowers the throughput.

According to the present invention, when a pattern on a reticle surface as a first object is projected on a wafer surface as a second object by a projection optical system, an image forming plane (focus position) of the projection optical system is used.
A projection exposure apparatus and a projection exposure apparatus capable of easily manufacturing a highly integrated semiconductor device in a short time and with high accuracy without moving and scanning the stage in the optical axis direction. The purpose of the present invention is to provide a method for manufacturing a semiconductor device.

[0008]

According to the present invention, there is provided a projection exposure apparatus comprising: (1-1) a first stage in which a pattern on a first object surface illuminated by exposure light from an illumination unit is mounted on a movable stage by a projection optical system. (2) In a projection exposure apparatus for projecting onto an object plane, a reflecting surface is provided on the movable stage and a reference mark is provided substantially on the same plane as the first object surface, and the reflecting surface is provided on an image forming surface of the projection optical system. The reference mark is illuminated in a state of being inclined with respect to the reference mark, the reference mark is projected on the reflection surface through the projection optical system, and the light beam reflected by the reflection surface is transmitted through the projection optical system and the reference mark. Light is received while the movable stage is driven in the direction of inclination of the reflection surface by the light receiving means, and the imaging position information of the projection optical system is obtained by the control means using a signal from the light receiving element. .

In particular, (1-1-1) a light projecting means for projecting a light beam on the reflecting surface without passing through the projection optical system, and a light receiving means for receiving the light beam reflected from the reflecting surface by the light receiving means Providing a position detecting means having, and detecting the surface position information of the reflecting surface in the optical axis direction of the projection optical system by the position detecting means,
(1-1-2) that the calibration of the surface position information obtained by the position detection means using the imaging position information obtained by the control means, (1-1-3) the reflection surface (1-1-4) the reflecting surface is formed by rotating the movable stage to rotate the movable stage, and the imaging surface of the projection optical system is tilted with respect to the imaging surface of the projection optical system. And the like.

(1-2) A projection exposure apparatus for projecting a pattern on a first object surface illuminated by exposure light from an illumination means onto a second object surface mounted on a movable stage by a projection optical system. A reference surface on which a plurality of reference marks are provided, illuminating the reference mark in a state where the reference surface is inclined with respect to an image forming plane of the projection optical system, the projection optical system and the first object The movable stage is driven in the direction of inclination of the reference surface while receiving the image of the reference mark through the surface by the light receiving means, and the control means uses the signal from the light receiving means to form an image of the projection optical system. It is characterized in that position information is required.

The scanning projection exposure apparatus according to the present invention includes: (2-1) a second object mounted on a second movable stage by a projection optical system by using a pattern on a first object surface mounted on a first movable stage. A first movable stage in a scanning type projection exposure apparatus that performs projection exposure while scanning the first and second movable stages on a surface in synchronization with a speed ratio corresponding to a photographing magnification of the projection optical system by scanning the first and second movable stages. A reference plate is provided on the second movable stage, and a reflection surface is provided on the second movable stage. The reference plate is illuminated with the reflection surface inclined with respect to the imaging plane of the projection optical system. The second movable stage is projected on the reflecting surface through the system, and the light beam reflected by the reflecting surface is driven through the projection optical system and the reference plate, and then the second movable stage is driven by the light receiving means in the tilt direction of the reflecting surface. While receiving the light from the light receiving element. It is characterized in that the control means obtains the image forming position information of the projection optical system using the signal.

In particular, (2-1-1) a light projecting means for projecting a light beam onto the reflecting surface without passing through the projection optical system, and a light receiving means for receiving the light beam reflected from the reflecting surface by the light receiving means Providing a position detecting means having, and detecting the surface position information of the reflecting surface in the optical axis direction of the projection optical system by the position detecting means,
(2-1-2) that the calibration of the surface position information obtained by the position detection means using the imaging position information obtained by the control means, (2-1-3) the reflection surface is (2-1-4) The reflecting surface is configured to rotate the second movable stage to rotate the second movable stage and form an image of the projection optical system. It is characterized by being inclined with respect to the image plane.

(2-2) The pattern on the first object surface mounted on the first movable stage is projected onto the second object surface mounted on the second movable stage by the projection optical system by the scanning means.
An image forming surface of the projection optical system on the first movable stage in a scanning type projection exposure apparatus that performs projection exposure while scanning the second movable stage in synchronization with a speed ratio corresponding to a photographing magnification of the projection optical system. A reference plate is provided on the second movable stage, and the reference plate is illuminated; the reference plate is projected onto the reflection surface via the projection optical system; After receiving the light beam reflected by the surface through the projection optical system and the reference plate, the light receiving unit receives the light beam while driving the first movable stage or the second movable stage in the tilt direction of the reflection surface, and receives the light beam from the light receiving element. And the control means obtains the image forming position information of the projection optical system by using the above-mentioned signal.

In particular, (2-2-1) a light projecting means for projecting a light beam on the reflecting surface without passing through the projection optical system, and a light receiving means for receiving the light beam reflected from the reflecting surface by the light receiving means Providing a position detecting means having, and detecting the surface position information of the reflecting surface in the optical axis direction of the projection optical system by the position detecting means,
(2-2-2) The surface position information obtained by the position detecting means is calibrated using the image forming position information obtained by the control means.

The method for manufacturing a device according to the present invention comprises the following steps.
After aligning the reticle with the wafer using the projection exposure apparatus of (1) or the scanning projection exposure apparatus of (2-1) or (2-2), the pattern on the reticle surface is aligned on the wafer surface. The device is characterized in that devices are manufactured through a development process step after the wafer is exposed to light.

[0016]

FIG. 1 is a schematic view of a main part of a projection exposure apparatus according to a first embodiment of the present invention, and FIG. 2 is an explanatory view of a part of FIG.

In FIG. 1, reference numeral 800 denotes an exposure illumination system (illumination means) which illuminates the reticle 1 as a first object and illuminates a reference mark 50 described later with a light beam from the exposure illumination system 800. The reference mark 50 has a configuration in which a plurality of slit openings are arranged in the X direction and the Y direction, as shown in FIG. The exposure illumination system 800 includes, for example, an aperture of the exposure illumination system, an ultra-high pressure mercury lamp, a shutter, an optical system, and the like.

Reference numeral 1 denotes a reticle (photomask) as a first object, and a circuit pattern 1a formed by chrome deposition or the like is provided on the lower surface of the reticle 1. Reference numeral 1b denotes a reticle stage (reticle holder) that holds the reticle 1 and is movable in the X and Y directions. The reticle holder 1b holds the reticle 1 by suction and moves two-dimensionally in a second orthogonal coordinate system XY in a plane parallel to the XY plane of the first orthogonal coordinate system. The origin of the second orthogonal coordinate system XY is the optical axis of the projection lens 2.

Reference numeral 2 denotes a projection lens (projection optical system) which projects the circuit pattern 1a of the reticle 1 illuminated by the exposure illumination system 800 onto a wafer 3 as a second object. Reference numeral 3a denotes a wafer holder, which holds the wafer 3 by suction. Reference numeral 5 denotes a movable stage (XY stage, wafer stage) for moving the wafer holder 3a to tilt driving means 90.
With 0, a minute rotation drive (θ drive) around the Z axis, a minute drive (Z drive) in the Z direction, a minute rotation drive (tilt drive) around the X axis and the Y axis, and drive control means 100
By 0, two-dimensional driving is performed in the first orthogonal coordinate system XY direction. 5a is a surface plate.

Reference numeral 81a denotes an interference mirror,
Is fixed to the position and its position is interferometer (laser interferometer)
It is for monitoring at 81. The interferometer mirror 81a and the interferometer 81 are similarly arranged in the direction perpendicular to the paper surface (Y direction). The laser beams from the two interferometers are set to coincide on the optical axis of the projection lens 2. Using the signals obtained from the interferometer mirror 81a and the interferometer 81, the XY drive control system 1000 positions the wafer 3 so that it is always at a predetermined position.

That is, while the XY stage 5 is moving or at rest, the position of the XY stage 5 with respect to the optical axis of the projection lens 2 which is the origin of the first orthogonal coordinate system XY preset in the apparatus is sequentially measured. XY stage control system 10
00, the XY stage 5 is positioned at a predetermined position.

A reflecting surface plate 12 has a reflecting surface (inclined reflecting surface) 12a and is provided on the stage 5. The reflecting surface 12a of the reflecting surface plate 12 is inclined at a predetermined angle θ with respect to the image plane of the projection lens 2 around the Y axis in the X direction.
The height of the center of the reflection surface 12a (position in the Z direction, position in the optical axis direction) is substantially the same as the height of the surface of the wafer 3.

Numeral 33a denotes a light projecting means for irradiating the reflecting surface 12a obliquely with a light beam which does not expose the photoresist applied to the wafer 3 to detect the surface position of the wafer 3, ie, the reflecting surface 12a in the optical axis direction. ing. Reference numeral 33b denotes a light receiving means (gap sensor) which measures the distance in the optical axis direction between the projection lens 2 and the wafer 3 or the reflection surface 12a without passing through the projection lens 2.

Light emitting means 33a and gap sensor 33b
Constitutes one element of the position detecting means. The gap sensor 33b detects the height (surface position information) of the surface of the wafer 3 with respect to the projection lens 2, and the detected value is a predetermined best focus value Za (a predetermined command value indicating the height of the image plane of the projection lens 2). ), The stage 5 drives the wafer 3 in the Z direction. Thereby, the circuit pattern 1a of the reticle 1
Is formed on the surface of the wafer 3. That is, focusing is performed so that a projection image with high contrast can always be transferred. The method of setting the predetermined best focus value Za will be described later.

In the present embodiment, the distance between them can be measured by leveling measurement.

Reference numeral 100 denotes a focus measuring optical system, which detects an image forming position of the projection lens 2, that is, a best focus position.

Next, each element constituting the focus measuring optical system 100 will be described in order. Reference numeral 200 denotes an optical fiber or a drawing optical system that guides a light beam from the exposure illumination system 800 to the focus measurement optical system 100.
Reference numeral 200a denotes a shutter, and 200b denotes an ND filter for adjusting the amount of incident light, which has a structure that can be put in and taken out of the optical path. Reference numerals 102a and 102b denote illumination optical systems (condenser lenses) for focus measurement. 105
Is a half mirror. 104 is a condenser lens, 103 is a light receiving element (light receiving means). Reference numeral 1100 denotes a focus position detection control unit (control unit).

A part of the light beam from the illumination optical system 800 is condensed by the condenser lens 102b via the fiber 200, the shutter 200a, and the ND filter 200b, and is incident on the half mirror 105. The light beam reflected by the half mirror 105 passes through the condenser lens 102a and passes through the mirror 106
After being reflected by and changing the direction, the reference mark 50 is illuminated. The reference mark 50 forms an image on the reflection surface plate 12 provided on the wafer stage 5 via the projection optical system 2. In the present embodiment, the reference mark 50 may be illuminated with a light beam from an illumination system other than the illumination optical system 800.

In the present embodiment, the reference mark 50 is arranged at a position equivalent to the reticle surface 1 or the reticle surface, the inclined reflecting surface 12 is arranged on the wafer stage 5, and the image from the reference mark 50 is inclined. A wafer stage that projects onto the reflection surface 12 and guides a reflected light beam from the inclined reflection surface 12 to the photoelectric conversion element 103 via the projection lens 2 and the reference mark 50, and includes the inclined reflection surface 12. 5 is continuously scanned in the horizontal direction in a direction having an inclination, so that the optimum surface position of the projection lens 2 in the optical axis direction is detected.

Next, the principle of the method of detecting the position of the image plane of the projection exposure apparatus (projection optical system 2) in this embodiment will be described.

First, the wafer stage 5 is driven by the drive control means 1000, and the reflection surface plate 12 is positioned below the reference mark 50 on the reticle 1 via the projection optical system 2. A part of the light beam from the illumination optical system 800 is guided by the fiber 200, condensed by the focus measurement optical system 100, and illuminates the reference mark 50. Fiducial mark 5
After passing through the projection optical system 2, the light flux passing through the reflection surface 12 a is condensed on the inclined reflection surface 12 a on the reflection surface plate 12,
It is reflected at 2a. Reflecting surface 12a of reflecting surface plate 12
The light beam reflected by the optical path returns to the original optical path and returns to the projection optical system 2 again.
Is condensed on the reference mark 50 surface. At this time, after a part of the light beam has passed through the reference mark 50, the mirror 106, the condenser lens 102, the half mirror 105, and the condenser lens 10
4 and enters the light receiving element 103. The light receiving element 1
Numeral 03 may be a simple photoelectric conversion element for light quantity detection. The reference mark 50 and the light receiving element 103 are in a conjugate relationship. In this state, while keeping the inclination of the inclined reflecting surface 12a of the reflecting surface plate 12 on the wafer stage 5 constant, the drive control means 1000 sandwiching the position expected to be the focal plane of the projection optical system 2
Drives the wafer stage 5 in the X direction.

Now, as shown in FIGS. 2B to 2A, when the wafer stage 5 is driven by .DELTA.X in the X direction, the reflection position of the luminous flux on the inclined reflecting surface 12a becomes .DELTA.Z in the Z direction. Only change. The Z change amount in the Z direction due to the X drive is
If the Z change amount is ΔZ, the X drive amount is ΔX, and the inclination of the inclined reflecting surface 12a is θ, the following is obtained.

ΔZ = ΔX × tan θ The measurement resolution is about 3400 times when the inclination amount is 1 ′ (= 3400 times).
1 / tan1 ') It turns out that it becomes loose. Compared with driving in other steps in the Z direction, in the present invention, the scanning can be roughly continuously performed in the X direction, so that the measurement resolution is significantly improved. The area of the reference mark 50 is slightly smaller than the area of the reflection surface, and can be considered as a point in the drawing.

The inclined reflecting surface 12 on which the light beam for detection hits
The Z position of a is determined by the surface position detection mechanism 33 (33a, 33b).
Focus position detection control means (control means)
1100. At this time, the photoelectric conversion output of the light receiving element 103 is simultaneously monitored and stored in the focus position detection control unit 1100. From the information from these,
The change in the photoelectric conversion output with respect to the change in the Z direction as shown in FIG. 5 is obtained. The position BF in the Z direction at which the photoelectric conversion output has the maximum value is the best imaging position of the reference mark 50.
The best imaging plane position of the reference mark 50 is determined by the focal position detection control unit 1100 using the signal from the light receiving element 103, and the best imaging plane position of the exposure area is calculated.

The origin of the surface position of the surface position detecting mechanism 33 is corrected using the best image forming surface position obtained here and stored in the focal position detection control means 1100, so that the image surface of the projection optical system 2 is corrected. The position and the surface position of the surface position detection mechanism 33 are calibrated (after the calibration is completed, the irradiation of the exposure light of the illumination system is stopped). The focus position detection control means 1100 adjusts the surface position of the wafer 3 in the optical axis direction of the projection optical system 2 when transferring the pattern to the surface position of the calibrated surface position detection mechanism 33. The angle of inclination of the inclined reflecting surface 12a is arbitrary in design. For example, if the amount of inclination of the inclined reflecting surface 12a used for measurement is set to one minute, ± 2 μm in the focus direction (Z direction) with an X scan of about ± 6.9 mm.
m can be measured.

The size of the reflecting surface plate 12 is sufficient if the length in the inclined direction is about 20 mm. The non-tilt direction is arbitrary. Regarding the size of the reference mark 50, it is preferable that the area be as small as possible as long as the amount of light necessary for the measurement in the electric processing is sufficient. By doing so, the area occupied by the mark on the reticle 1 can be reduced. □ 500 on reticle 1
μm is sufficient, and in the case of the projection optical system 2 having a projection magnification of ５, □ 1 on the reflection surface on the wafer stage 5.
It is about 00 μm. By arranging a plurality of minute reference marks at arbitrary positions on the reticle 1 and detecting the focal position at each point, it is possible to measure the residual aberration and the like (field curvature and the like) of the projection optical system 2. It is possible.

If the mark area is lengthened in the non-inclined direction of the inclined reflection surface 12a, the detected light amount can be increased.
Further, since the inclined reflecting surface 12a has an inclination, the return reflected light beam is shaken by an aperture stop or the like in the projection optical system 2 and there is a concern that the detected light amount may be reduced, but this can be ignored for the following reasons.

The NA of the projection optical system 2 is 0.4 to 0.6, which corresponds to 24 to 37 degrees in a half angle of the solid angle. On the other hand, when the inclination angle of the inclined reflecting surface 12a is set to 1 ', the angle change of the reflected return light beam is 2' (= 0.03).
°). The rate of decrease in the amount of light due to shaking is approximately as follows.

100 × 0.03 / 24 = 0.125% Therefore, when detecting a change in the detected light amount, the amount becomes negligible.

The timing of performing the calibration may be simultaneously performed in a sequential batch exposure type reduction projection exposure apparatus during a series of operations for driving the stage in the horizontal direction, such as at the time of alignment or wafer feeding.

FIG. 6 shows an example of the arrangement of the reflection surface plates 12 (12a, 12b, 12c) on the wafer stage 5. In the periphery of the wafer 3, the arrangement position is arbitrary as long as the position can be detected by the oblique incidence surface position detection mechanism 33 without passing through the projection optical system 2. By providing a plurality of reflection surface patterns 12 on the wafer stage 5 and arranging them so that their inclination directions are orthogonal to each other, the stage scanning direction at the time of measurement can be arbitrarily selected in both the X and Y directions. By providing a plurality of reflection surface patterns 12 on the wafer stage 5 and setting the respective inclination angles to different amounts, measurement suitable for the detection resolution and the detection time may be selected.

FIG. 3 shows a second embodiment of the projection exposure apparatus of the present invention.
FIG. In the figure, the same elements as those shown in FIG. 1 are denoted by the same reference numerals.

In the first embodiment, the case where the reflection surface 12a of the reflection surface plate 12 has an inclination has been described. In this embodiment, the reflection surface plate 13 is a parallel plane plate, and the reflection surface 13a is also inclined. Has no reflective surface. The oblique incidence surface position detection mechanism 33 that does not pass through the projection optical system 2
While monitoring the amount of tilt in the wafer stage 5
The entirety is tilt-driven by the tilt drive unit 900, and scanning is performed in the horizontal (X or Y) direction in the same manner as in the first embodiment while maintaining the tilt amount, thereby detecting the focal position in the Z direction.

In this case, the inclination angle of the reflection surface 13a can be set arbitrarily, and it is possible to select a measurement suitable for the detection resolution and the detection time. Reflective surface 13
The inclination angle of “a” can be set while monitoring the amount of inclination by the oblique incidence surface position detection mechanism 33 that does not pass through the projection optical system 2.

FIG. 8 is a schematic view of a main portion of a scanning projection exposure apparatus according to a third embodiment of the present invention. In the figure, the same elements as those shown in FIG. 1 are denoted by the same reference numerals.

In this embodiment, projection exposure is performed while scanning the reticle 1 and the wafer 3 at a predetermined speed ratio while synchronizing with the image forming magnification of the projection optical system 2.

In FIG. 8, a reticle 1 on which an exposure pattern is formed is a laser interferometer 80 and a drive control means 100.
It is mounted on a reticle stage (first movable stage) 4 that is driven and controlled in the X direction by 0. The reticle stage 4 is driven in the X direction while keeping the position in the Z direction constant with respect to the projection optical system 2. The wafer 3, which is a photosensitive substrate, is mounted on a wafer stage (second movable stage) 5 that is driven and controlled in the X and Y directions by a laser interferometer 81 and a drive control unit 1000. Further, the wafer stage 5
The position and inclination in the Z direction can be drive-controlled with respect to the projection optical system 2.

The reticle 1 and the wafer 3 are connected to the projection optical system 2
And an exposure light beam 6 on a slit long in the Y direction is formed on the reticle 1 from an illumination system (not shown). The exposure light beam 6 on the reticle 1 forms a slit-like exposure light beam 6 ′ on the wafer 3 having a size corresponding to the projection magnification of the projection optical system 2. The scanning type reduction projection exposure apparatus moves both the reticle stage 4 and the wafer stage 5 in the X direction at a speed ratio corresponding to the optical magnification with respect to the slit-like exposure light beams 6 and 6 ′, 6 and 6 'are reticle 1
This is performed by scanning the upper pattern transfer area 51 and the pattern transfer area 22 on the wafer 3.

In FIG. 8, on reticle stage 4,
Plates 10 and 11 on which the pattern shown in FIG. 9 is formed
(Reference plate) is placed. Reference plate 1
Marks (reference marks) 50 and 51 are arranged on 0 and 11, and the marks 50 and 51 are at the same height as the pattern drawing surface of the reticle 1. The mark 50 is composed of, for example, a partially transparent line and space formed on a glass substrate by Cr vapor deposition and arranged at different positions 50a to 50c and 51a to 51c on the reference plates 10 and 11. The reason why a plurality of marks are arranged at different positions is to detect a change in the image plane in the slit longitudinal direction of the projection optical system 2.

The half mirrors 101 (101a, 101b, 101c) and 111 (1
11a, 111b, 111c) and the condenser lens 102 (1
02a, 102b, 102c), 112 (112a, 1
12b, 112c) and the light receiving element 103 (103a, 1
03b, 103c), 113 (113a, 113b, 1)
13c) is arranged. The half mirror, the condensing lens, and the light receiving element are provided at a plurality of positions 50a to 5 of the mark 50.
A plurality is provided individually corresponding to 0c and 51a to 51c.

On the other hand, a reflection surface plate 12 having a predetermined inclination is mounted on the wafer stage 5. The surface (reflection surface) 12 a of the reflection surface plate 12 is substantially at the same height as the surface of the wafer 3. The surface position of the wafer 3 on the optical axis of the projection optical system 2 is detected by a surface position detection mechanism 33 for oblique incidence. The surface position detection mechanism 33 can detect the position and the inclination in the Z direction.

Next, the calibration of the scanning type projection exposure apparatus of this embodiment will be described. Calibration can be performed using either the mark 50 or the mark 51, and the mark 50 (50a, 50a,
50b, 50c) will be described.

First, the reticle stage 4 and the wafer stage 5 are driven by the drive control means 1000 so that the reference plate 10 on the reticle stage 4 and the reflecting surface plate 12 on the wafer stage 5 are positioned on the optical axis of the projection optical system 2. Position. At this time, the mark 50a on the reference plate 10
... 50b are set to coincide with the area illuminated by the slit-shaped exposure light flux 6. Illumination light is emitted from an illumination system (not shown). The illumination light passes through the half mirror 101 and illuminates the mark 50 on the reference plate 10. The light beam that has passed through the mark 50 passes through the projection optical system 2,
The light is condensed on 2 and reflected. The light beam reflected by the reflecting surface plate 12 is condensed on the mark 50 again via the projection optical system 2. At this time, a part of the light beam passes through the mark 50 and is reflected by the half mirror 101, and then enters the light receiving element 103 through the condenser lens 102.

In this state, while keeping the inclination of the reflection surface plate 12 on the wafer stage 5 constant, the drive control means 100 is positioned across the position expected to be the focal plane of the projection optical system 2.
0 drives the wafer stage 5 in the X direction.
The drive position of the wafer stage 5 in the X direction is monitored by the surface position detection mechanism 33 and stored by the focus position detection means 1100. At this time, the photoelectric conversion output of the light receiving element 103 is also monitored, and the focus position detection control means 110
0 is stored.

The light receiving element 103 (103a to 103)
In (c), the outputs of the light receiving elements 103a to 103c corresponding to the marks 50a to 50b on the reference plate 10 are obtained.
The positions in the Z direction where the photoelectric conversion outputs from the light receiving elements 103a to 103c have the maximum value are the marks 50a to 50c.
c is the best imaging position. Focus position detection control means 110
Based on 0, the best imaging position of each of the marks 50a to 50c is determined, and the best imaging plane position including the inclination of the slit-shaped exposure area 6 'is calculated.

The origin of the surface position of the surface position detecting mechanism 33 is corrected using the best image forming surface position obtained here and is stored in the focal position detection control means 1100, whereby the image surface of the projection optical system 2 is corrected. The position and the surface position of the surface position detection mechanism 33 are calibrated (after the calibration is completed, the illumination of the exposure light of the illumination system is stopped). The focus position detection control means 1100 adjusts the surface position of the exposure region 22 of the wafer 3 when transferring the pattern to the surface position of the calibrated surface position detection mechanism 33.

The timing at which the calibration is performed may be performed during a series of pattern transfer operations to the wafer 3 or may be performed independently of the pattern transfer operation. The calibration may be performed using either of the marks 50 and 51. However, since the position of the reticle stage 4 at the time of performing the calibration is not always at the driving center in the X direction, the reticle stage It is more desirable to perform calibration using a mark that requires less movement of the reticle stage 4 in the X direction because throughput can be improved. (Because of reduced projection, the movement amount of the reticle stage 4 is larger than the movement amount of the wafer stage 5. Because it is larger by the minute and the travel time is also longer.)

FIG. 10 is a schematic view of a main part of a scanning projection exposure apparatus according to a fourth embodiment of the present invention. 8, the same elements as those shown in FIG. 8 are denoted by the same reference numerals. In the present embodiment, as compared with Embodiment 3 of FIG. 8, as shown in FIG. 10, two reflecting surface plates 1 having a longer inclination on the wafer stage 5 in the same direction as the longitudinal direction of the slit exposure region 6 ′.
The difference is that 2d and 12e are arranged in the X direction for scanning and driving the wafer 3, and the other configurations are substantially the same.

The reflecting surface plate 12 in the present embodiment
The lengths of d and 12e in the Y direction are longer than the diameter of the wafer 3 on which pattern transfer is performed. Further, they are arranged so as to have an inclination in the exposure scan driving direction.
When calibration is performed during a series of operations for transferring a pattern to the wafer 3, not only the reticle stage 4 but also the wafer stage 5 need only be driven in the X direction for scan driving, and the wafer stage 5 is moved in the Y and Z directions. The throughput is improved by not moving to the target.

The marks 5 on the reference plates 10 and 11
Calibration may be performed by using 0, 51, or any of them. However, since the position of the reticle stage 4 at the time of performing the calibration is not always at the driving center in the X direction, the reticle stage 4 Calibration is performed using a mark that requires less movement in the X direction. The reflection plates 12d and 12e on the wafer stage 5 are also calibrated by using the reflection plate that requires less movement in the X direction.

Next, a fifth embodiment of the projection exposure apparatus of the present invention will be described.
Will be described. 8 and 10 show the examples in which the reference plates 10 and 11 are arranged on the reticle stage 4, the present embodiment has a configuration in which the reference plate 100 is arranged on the wafer stage 5. In this case, the calibration detection system (102 to 1) shown in FIG.
06), and the projection optical system 2 is irradiated with light from the wafer stage 5 side.

In this case, the reference plates 10 and 11 shown in FIG.
A reflection plate having an inclined reflection surface is formed at a position corresponding to the above, and reflects light from the projection optical system 2.
The center of the inclined reflecting surface of the reflecting plate is at the same height as the pattern drawing surface of the reticle 1. When a reference reflecting surface is provided on the reticle side, it is necessary to set a large inclination amount by a predetermined amount in accordance with the magnification of the projection optical system.

In this embodiment, the positions of the reference plate and the reflection surface plate having the structure shown in FIG.
The other description is substantially the same as FIG. 8 or FIG.

The method described so far is a case in which an inclined reflection surface is applied to the focus measurement method by the self-conjugate method. However, a mark for measurement is not provided on the reticle side, and a surface having an inclination on the stage side is used. Multiple measurement marks,
It is also effective for a method of acquiring the image information via the projection optical system and measuring the best imaging position from the image contrast.

In this case, in FIG.
A plurality of marks as shown in FIG. 4 may be set on the inclined surface such as e by a distance corresponding to the focus pitch to be measured in the inclined direction. A mark may not be provided on the reticle on the reticle stage or on the reference plate, and the mark may be provided as a transmission portion. Sensor 103a, 103
b, 103c and 113a, 113b, 113c are CCs
If a position detecting element such as D is used, it is easy to obtain image information of the reference mark on the inclined surface on the stage.

Next, an embodiment of a device manufacturing method using the above-described projection exposure apparatus or scanning projection exposure apparatus will be described.

FIG. 11 shows a flow of manufacturing a semiconductor device (a semiconductor chip such as an IC or an LSI, or a liquid crystal panel or a CCD).

In step 1 (circuit design), the circuit of the semiconductor device is designed. Step 2 is a process for making a mask on the basis of the circuit pattern design. On the other hand, in step 3 (wafer manufacturing), a wafer is manufactured using a material such as silicon. Step 4 (wafer process) is called a pre-process, and an actual circuit is formed on the wafer by lithography using the prepared mask and wafer.

The next step 5 (assembly) is called a post-process, and is a process of forming a semiconductor chip using the wafer produced in step 4, and includes an assembly process (dicing and bonding) and a packaging process (chip encapsulation). And the like. In step 6 (inspection), inspections such as an operation confirmation test and a durability test of the semiconductor device manufactured in step 5 are performed. Through these steps, a semiconductor device is completed and shipped (step 7).

FIG. 12 shows a detailed flow of the wafer process. Step 11 (oxidation) oxidizes the wafer's surface. Step 12 (CVD) forms an insulating film on the wafer surface. Step 13 (electrode formation) forms electrodes on the wafer by vapor deposition. In step 14 (ion implantation), ions are implanted into the wafer. Step 1
In 5 (resist processing), a photosensitive agent is applied to the wafer. Step 16 (exposure) uses the above-described exposure apparatus to print and expose the circuit pattern of the mask onto the wafer.

In step 17 (development), the exposed wafer is developed. In step 18 (etching), portions other than the developed resist image are removed. In step 19 (resist stripping), the resist that has become unnecessary after the etching is removed. By repeating these steps, multiple circuit patterns are formed on the wafer.

By using the manufacturing method of this embodiment, it is possible to manufacture a highly integrated semiconductor device which has been conventionally difficult to manufacture.

[0073]

According to the present invention, by setting each element as described above, when the pattern on the reticle surface as the first object is projected on the wafer surface as the second object by the projection optical system, The imaging plane (focus position) of the projection optical system can be detected in a short time and with high accuracy without moving and scanning the stage in the direction of the optical axis, and a highly integrated semiconductor device can be easily manufactured. And a semiconductor device manufacturing method using the same.

[Brief description of the drawings]

FIG. 1 is a schematic view of a main part of a projection exposure apparatus according to a first embodiment of the present invention.

FIG. 2 is an explanatory view of the reflection surface plate of FIG. 1;

FIG. 3 is a schematic view of a main part of a projection exposure apparatus according to a second embodiment of the present invention.

FIG. 4 is an explanatory diagram of a reference mark in FIG. 1;

5 is an explanatory diagram of a signal output from the light receiving element in FIG.

FIG. 6 is an explanatory diagram on the wafer stage of FIG. 1;

FIG. 7 is a flowchart of the operation of the projection exposure apparatus according to the first embodiment of the present invention.

FIG. 8 is a scanning projection exposure apparatus according to a third embodiment of the present invention.
Main part schematic diagram of

FIG. 9 is an explanatory view of the reference plate of FIG. 8;

FIG. 10 is a schematic view of a main part of a scanning projection exposure apparatus according to a fourth embodiment of the present invention.

FIG. 11 is a flowchart of a device manufacturing method according to the present invention.

FIG. 12 is a flowchart of a device manufacturing method according to the present invention.

[Explanation of symbols]

 800 Exposure illumination system (illumination means) 1 Reticle (first object) 2 Projection optical system 3 Wafer (second object) 4 Reticle stage (first movable stage) 5 Wafer stage (second movable stage) 50 Reference mark 12 Reflecting surface Plate 12a Reflecting surface 10, 11 Reference plate 1100 Control means 33 (33a, 33b) Position detecting means 103 Light receiving means

Claims (16)

[Claims] 1. A projection exposure apparatus for projecting a pattern on a first object surface illuminated with exposure light from an illumination means onto a second object surface mounted on a movable stage by a projection optical system,
A reference mark is provided on the movable stage with a reflecting surface substantially on the same plane as the first object surface, and the reference mark is illuminated in a state where the reflecting surface is inclined with respect to the imaging plane of the projection optical system. Projecting the fiducial mark onto the reflecting surface via the projection optical system,
The light beam reflected by the reflecting surface is received by the light receiving means via the projection optical system and the reference mark while driving the movable stage in the direction of inclination of the reflecting surface, and the control means uses a signal from the light receiving element. Wherein the imaging position information of the projection optical system is obtained by the following. 2. A position detecting device comprising: a light projecting device for projecting a light beam onto a reflecting surface without passing through the projection optical system; and a light receiving device for receiving a light beam reflected from the reflecting surface by a light receiving device. 2. The projection exposure apparatus according to claim 1, wherein said position detecting means detects surface position information of said reflection surface in an optical axis direction of said projection optical system. 3. The projection exposure apparatus according to claim 2, wherein the surface position information obtained by the position detecting means is calibrated using the image forming position information obtained by the control means. 4. The projection exposure apparatus according to claim 1, wherein said reflection surface comprises an inclined reflection surface which is inclined with respect to an image forming surface of said projection optical system. 5. The projection exposure apparatus according to claim 1, wherein the reflecting surface is tilted with respect to an image forming surface of the projection optical system by rotating the movable stage. 6. The first and second movable stages are scanned by scanning means on a pattern on a first object surface mounted on a first movable stage on a second object surface mounted on a second movable stage by a projection optical system. In a scanning projection exposure apparatus that performs projection exposure while scanning in synchronization with a speed ratio corresponding to the photographing magnification of the projection optical system, a reference plate is provided on the first movable stage and a reflection surface is provided on the second movable stage. Illuminating the reference plate in a state where the reflection surface is inclined with respect to the imaging plane of the projection optical system, projecting the reference plate onto the reflection surface via the projection optical system, The light beam reflected by the surface is received through the projection optical system and the reference plate while receiving light while driving the second movable stage in the direction of inclination of the reflection surface, and is controlled using a signal from the light receiving element. Imaging of the projection optical system by means A scanning type projection exposure apparatus wherein position information is obtained. 7. A position detecting device comprising: a light projecting device for projecting a light beam onto a reflecting surface without passing through the projection optical system; and a light receiving device for receiving a light beam reflected from the reflecting surface by a light receiving device. 7. A scanning projection exposure apparatus according to claim 6, wherein said position detecting means detects surface position information of said reflection surface in the optical axis direction of said projection optical system. 8. A scanning type projection exposure apparatus according to claim 7, wherein calibration of surface position information obtained by said position detecting means is performed using image forming position information obtained by said control means. . 9. The scanning projection exposure apparatus according to claim 6, wherein said reflecting surface is formed of an inclined reflecting surface inclined with respect to an image forming surface of said projection optical system. 10. The scanning projection exposure apparatus according to claim 6, wherein said reflection surface is tilted with respect to an image forming surface of said projection optical system by rotating said second movable stage. . 11. A first optical system for projecting a pattern on a first object surface mounted on a first movable stage onto a second object surface mounted on a second movable stage by a projection optical system. In a scanning type projection exposure apparatus that performs projection exposure while scanning in synchronization with a speed ratio corresponding to the photographing magnification of the projection optical system, the projection optical system tilts with respect to the image forming plane of the projection optical system on the first movable stage. A reference plate is provided on each of the second movable stages, the reference plate is illuminated, the reference plate is projected on the reflection surface via the projection optical system, and reflected by the reflection surface. The light beam is received through the projection optical system and the reference plate while receiving light while driving the first movable stage or the second movable stage in the direction of inclination of the reflecting surface by a light receiving means, and a signal from the light receiving element is used. By the control means A scanning projection exposure apparatus, wherein information on an image forming position of an optical system is obtained. 12. A position detecting means comprising: light projecting means for projecting a light beam onto a reflecting surface without passing through the projection optical system; and light receiving means for receiving a light beam reflected from the reflecting surface by a light receiving means. 12. A scanning projection exposure apparatus according to claim 11, wherein said position detecting means detects surface position information of said reflection surface in the optical axis direction of said projection optical system. 13. The surface position information obtained by said position detecting means is calibrated using the image forming position information obtained by said control means.
Scanning projection exposure apparatus. 14. A pattern on a reticle surface is projected and exposed on a wafer surface after a reticle and a wafer are aligned using the projection exposure apparatus according to claim 1. And a method for manufacturing a device by subjecting the wafer to a development process. 15. A pattern on a reticle surface is projected onto a wafer surface after a reticle and a wafer are aligned using the scanning projection exposure apparatus according to claim 6. And thereafter manufacturing the device through the developing process of the wafer. 16. The first illuminated by exposure light from an illuminating means.
In a projection exposure apparatus for projecting a pattern on an object surface onto a second object surface mounted on a movable stage by a projection optical system, a reference surface provided with a plurality of reference marks is provided on the movable stage; Illuminates the fiducial mark in a state where the fiducial mark is inclined with respect to the imaging plane of the projection optical system, and receives the image of the fiducial mark through the projection optical system and the first object plane with light receiving means, A projection exposure apparatus wherein a stage is driven in a direction of inclination of the reference plane, and information on the image forming position of the projection optical system is obtained by control means using a signal from the light receiving means.