JPH09312248A - Exposure device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make exposure onto both surface of a wafer with high accuracy. SOLUTION: An alignment mark is formed on a surface of a wafer 11, alignment is performed by alignment microscopes 17a and 17b and exposure is performed. After finishing the exposure the wafer 11 is reversed by a wafer carrying arm 24, the alignment is performed by alignment microscopes 17c and 17d and the exposure is performed on the other surface.

Description

Detailed Description of the Invention

[0001]

The present invention relates to an exposure apparatus,
In particular, the present invention relates to an exposure apparatus that performs exposure after adjusting the relative positional relationship between the semiconductor substrate and the mask.

[0002]

2. Description of the Related Art FIG. 6 is a diagram for explaining an exposure process in a conventional exposure apparatus. FIG. 6A shows the positional relationship of each part of the apparatus when performing the so-called alignment for adjusting the relative positions of the mask 1 and the wafer 2.
Two cross-shaped transmission patterns (mask-side alignment patterns 5a and 5b) as shown in FIG. 8 are formed on the upper surface (upper side of the drawing) of the mask 1. In addition, on the surface A of the wafer (semiconductor substrate) 2, the same spacing as the mask-side alignment patterns 5a and 5b of the mask 1,
Cross-shaped marks (wafer-side alignment marks 5c and 5d) that are the same as the mask-side alignment patterns 5a and 5b.
Are formed.

When exposing the surface A, as shown in FIG. 6A, the mask-side alignment patterns 5a and 5b formed on the mask 1 and the wafer-side alignment marks formed on the surface A of the wafer 2 are exposed. The relative positions of the mask 1 and the wafer 2 are adjusted by manual operation so that 5c and 5d match. That is, the mask side twin objective lens 3a,
Since the image from 3b is combined into one visual field as shown in FIG. 9, the operator observes this image through an eyepiece lens (not shown), and the mask-side alignment pattern formed on the mask 1 is observed. These positions are adjusted so that the wafer-side alignment marks 5c and 5d formed on the surface A of the wafer 2 are exactly aligned with each other.

When the alignment is completed, next, the mask 1 and the wafer 2 are brought into close contact with each other (or brought into close proximity to each other), and exposure is performed by the light source device 4 (see FIG. 6B). The exposure of the surface A of the wafer 2 is completed by the above process.

Then, after the mask 1 and the wafer 2 are separated, the wafer 2 is turned upside down, and is placed opposite to the mask 1 with the surface B facing upward as shown in FIG. 7 (a).

At this time, the reflected light from the wafer-side alignment marks 5c and 5d formed on the surface A of the wafer 2 is condensed by the wafer-side twin objective lenses 3c and 3d, and one field of view is obtained as shown in FIG. Is synthesized. Further, the mask-side alignment pattern 5 formed on the mask 1
The light that has passed through a and 5b is reflected by the mask side twin objective lens 3a,
After being condensed by 3b and synthesized into one visual field, as shown in FIG. 9, it is superposed on the images from the wafer side twin objective lenses 3c and 3d. In addition, the mask side twin objective lens 3a,
Since the optical axes of 3b and the wafer-side bi-objective lenses 3c and 3d are exactly coincident with each other, the mask-side alignment patterns 5a and 5b and the wafer-side alignment marks 5c and 5d are exactly in the observation field of view shown in FIG. By adjusting (aligning) so as to match, the mask 1 and the wafer 2 can be aligned so that the positions of the pattern exposed on the surface A and the pattern to be exposed on the surface B are exactly matched.

When the alignment is completed, the mask 1 and the wafer 2 are brought into close contact with each other (or brought into close proximity to each other), and the surface A
The surface B is exposed in the same manner as in the case (see FIG. 7B).

By the above operation, the exposure can be performed so that the positions of the patterns formed on the surface A and the surface B are exactly coincident with each other.

[0009]

However, in the conventional exposure apparatus as described above, when exposing the mask 1 and the wafer 2 in close contact with each other, the wafer 2 is separated when the mask 1 and the wafer 2 are separated. Since the resist applied on the mask 1 may adhere to the mask 1 and be peeled off, a defect occurs in the circuit pattern, resulting in a problem that the yield is reduced. There is also a problem that the resist attached to the mask 1 shortens the life of the mask 1.

Further, when the mask 1 and the wafer 2 are exposed in close proximity to each other, a gap between the mask 1 and the wafer 2 causes diffraction of the exposure beam, resulting in a problem that the resolution is lowered.

Further, since it is necessary to form wafer-side alignment marks 5c and 5d for alignment only on the wafer 2, there is a region (circuit pattern region) where a circuit pattern is formed in order to secure a region for forming these marks. There was a problem of narrowing. There is also a problem that a process for forming the wafer-side alignment marks 5c and 5d is newly required, which makes the processing process complicated.

The present invention has been made in view of the above situation, and when the circuit patterns are formed on both surfaces of the wafer 2, the positions of the circuit patterns formed on both surfaces are exactly the same. In addition to the above, it is possible to improve the exposure accuracy and thus the yield.

Further, according to the present invention, the alignment can be executed without complicating the process, and the circuit pattern area can be further widened.

[0014]

An exposure apparatus according to a first aspect of the present invention shows an exposure means for exposing a semiconductor substrate through a mask, a stage on which the semiconductor substrate is arranged, and a reference position of the stage. First measuring means for measuring the relative positional relationship between the fiducial mark and the semiconductor substrate when the semiconductor substrate is arranged on the stage so that one surface faces the exposure means. When,
The semiconductor substrate is arranged on the stage so that the first control means controls the relative positional relationship between the mask and the semiconductor substrate according to the measurement result of the first measurement means, and the other surface faces the exposure means. Second measuring means for measuring the relative positional relationship between the fiducial mark and the semiconductor substrate, and the relative positional relationship between the mask and the semiconductor substrate according to the measurement result of the second measuring means. And a second control means for controlling. The fiducial mark is a dedicated mark that serves as a reference position on the stage.
By measuring the positions of this mark and the alignment mark on the wafer, it becomes possible to measure the variation between the stage and the wafer.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing an example of the configuration of an exposure apparatus of the present invention. In this figure, a mask is not used in order to outline the principle of the exposure apparatus according to the present invention. Hereinafter, this embodiment will be described, and then the case where a mask is added to the configuration will be described with reference to FIG.

In this figure, a wafer (semiconductor substrate) 11 to be exposed is fixed at a predetermined position by a wafer holder 12. The wafer holder 12 is mounted on a θ stage 13 which is rotatable in the circumferential direction of the wafer 11. The θ stage 13 is mounted on an XY stage 14 (first control means, second control means) that is movable in the X or Y direction. In addition, these are placed on a surface plate 15 that supports the entire apparatus.

The displacement angle of the θ stage 13 is monitored by an encoder (not shown). Also, XY
The position (coordinates) of the stage 14 is similarly monitored by a laser interferometer (not shown). The encoder may be a linear type or a rotary type.

The optical system includes an objective lens 16a and an exposure light source 1.
6b (exposure means), light quantity control / beam shaping device 16c,
Also, it is configured by the reflecting mirror 16d. The light emitted from the exposure light source 16b is adjusted in light quantity and beam shape by the light quantity control / beam shaping device 16c, and then reflected by the reflecting mirror 16d to enter the objective lens 16a. The objective lens 16a is configured to converge the light incident on a predetermined area on the wafer 11.

Alignment microscopes 17a and 17b (first
Measuring means and detecting means) irradiate the alignment mark (not shown) formed on one surface (plane A) of the wafer 11 with light, and the reflected light is reflected by a CCD (Char (not shown)).
It is converted into an image signal by a ge coupled device) or the like and output to the image processing unit 22 (detection means). The illumination method for the alignment mark is, for example, an epi-illumination type or an oblique incidence type.

The alignment microscopes 17a and 17b, the exposure light source 16b, the light quantity control / beam shaping device 16c, the reflecting mirror 16d, and the objective lens 16a are mounted on a mount 18. The pedestal 18 is mounted on the surface plate 15.

The alignment microscopes 17c and 17d (second measuring means and detecting means) arranged on the lower side of the wafer 11 are arranged when the wafer 11 is inverted (when the surface A is arranged on the lower side). Then, the reflected light from the alignment mark formed on the surface A of the wafer 11 is converted into an image signal and supplied to the image processing unit 22.

The image signals output from the alignment microscopes 17a to 17d are supplied to the image processing unit 22 and subjected to predetermined processing, and then the control unit 23 (first
Control means, second control means). The control unit 23 controls a stepping motor (not shown) that drives the θ stage 13 or the XY stage 14 based on the signal supplied from the image processing unit 22.

The wafer storage cassette 20 is designed to store about 25 wafers 11. The wafer transfer arm 24 takes out the wafers 11 one by one from the wafer storage cassette 20 and transfers the wafers 11 one by one.
The wafer 11 which has been exposed is returned to the wafer storage cassette 20 while being arranged at a predetermined position. Further, when the surface B is exposed, the wafer 11 can be inverted.

The fiducial mark 25 includes a θ stage 13 and an XY stage 14 (hereinafter referred to as a stage system).
And is used as a reference for adjusting the relative positional relationship between the optical axis of the objective lens 16a and the optical axis of the objective lens 16a. An alignment mark similar to that formed on the wafer 11 is formed on the upper surface (upper side in the drawing) of the fiducial mark 25,
By observing the alignment marks with the alignment microscopes 17a and 17b, the relative positions of the optical axes of the stage system and the objective lens 16a are adjusted (ie,
The position (coordinates) of the optical axis of the objective lens 16a in the coordinates of the stage system is determined). The upper surface of the fiducial mark 25 (the surface on the side where the alignment mark is formed) is the alignment microscopes 17a and 17b.
It is set to have the same height as the surface of the wafer 11 to be processed so that the adjustment of the focal length is unnecessary.

Alignment microscopes 17a and 17c
Are adjusted so that their optical axes coincide.
The same applies to the alignment microscopes 17b and 17d. Further, the alignment mark formed on the surface A of the wafer 11 is formed at a position corresponding to the alignment microscopes 17a and 17b (or the alignment microscopes 17c and 17d).

Alignment microscopes 17a and 17c
Alternatively, the optical axes of the alignment microscopes 17b and 17d do not necessarily have to coincide with each other, and when the deviation between them is accurately grasped, the control unit 23 may perform control in consideration of the deviation. In order to measure the deviation of the optical axes of the alignment microscopes 17a to 17d, for example, instead of the wafer 11, a transparent plate having alignment marks is placed on the wafer holder 12,
The alignment mark can be accurately measured by observing the alignment mark with an opposing alignment microscope (alignment microscopes 17a and 17c or alignment microscopes 17b and 17d), and measuring the positional deviation between them by the image processing unit 22.

FIG. 2 shows an example of the alignment mark. As the alignment mark, a cross-shaped mark shown in FIG. 2A or a cross-shaped mark shown in FIG. 2B can be used.

It should be noted that, without using the mark formed exclusively for alignment as described above, it is formed for other purposes, for example, a wafer identification number, a wafer identification bar code, or a diffraction grating mark. Can also be used. When alignment is performed using such characters or figures, it is possible to omit the trouble of separately forming the alignment mark. Further, since it is not necessary to secure a portion where the alignment mark is formed, this area can also be used as a circuit pattern area (area for forming a circuit), so that the semiconductor substrate can be effectively used.

When using, for example, a wafer identification number, the number may be different for each wafer. In such a case, when the surface A is exposed, the control unit 23 stores information such as numbers and characters used as alignment marks for each wafer. Then, when the surface B is exposed, the alignment may be performed based on the stored information.

FIG. 3 shows an ITV (Indu) image obtained by the alignment microscopes 17a to 17d when performing alignment using the wafer identification number as an alignment mark.
(strial Television) 40 is displayed. The identification number (“2”) 45 is an image obtained by the alignment microscope 17a or 17b when the surface A is exposed. Such an image is displayed in the control unit 23
, And is read out when the surface B is exposed, and is displayed superimposed on an image including the identification number 46 obtained from the alignment microscope 17c or 17d.

As described above, the alignment microscopes facing each other with the wafer 11 in between are stored in the control unit 23 because the optical axes thereof match (or the shift is known). By controlling the stage system so that the identification number 45 included in the image and the identification number 46 included in the image signals obtained by the alignment microscopes 17c and 17d match when the surface B is aligned. , Alignment can be performed.

Further, a specific portion (for example, a predetermined wiring pattern or element pattern) of the circuit pattern can be used as an alignment mark. That is, a predetermined pattern formed by exposing (processing) the surface A
Alignment can be performed by using it as an alignment mark when exposing.

In this case, when the surface A is exposed, the alignment cannot be executed because the pattern is not formed yet. However, the relative position of the optical axis of the stage system and the objective lens 16a is accurately adjusted by the fiducial mark 25, and the error (deviation) when the wafer holder 12 holds the wafer 11 is sufficient. Since it is small (about several tens of microns), when the surface A is exposed, the alignment is not performed and the exposure is performed. Then, the image of the pattern formed by exposure is used as an alignment microscope 17a, 1a.
It is stored in the control unit 23 via 7b.

When the surface B is exposed, the control unit 23 moves the stage system so that the pattern used as the alignment mark is the alignment optical microscope 1.
7c, 17d so that the position is opposite. Then, using the pattern used as the alignment mark and the image stored in the control unit 23, alignment is performed by the same process as in the case described above, and then the exposure process is performed.

Since the circuit pattern includes many wirings and elements, it may be difficult to specify the portion used as the alignment mark. Therefore,
The coordinates of the pattern to be used are given to the control unit 23 in advance, the wafer 11 is moved based on the coordinates, and the alignment can be executed by finely adjusting the alignment microscopes 17a to 17d.

Next, the operation of this embodiment will be described.

When the wafer storage cassette 20 in which the wafers 11 to be processed are stored is set, the control unit 23 sends a control signal to the θ stage 13 or the XY stage 14 to set the fiducial mark 25 to the alignment microscope. 17a is moved directly below. Then, the control unit 23 refers to the image signal output from the image processing unit 22, and as shown in FIG. 4, the reference line 42 of the alignment microscope 17a and the fiducial mark 25.
Is controlled so as to coincide with the reference mark 41 formed on the upper surface of.

Then, the control unit 23 refers to the outputs of a linear encoder (not shown) and a laser interferometer that monitor the position of the stage system, and refers to the position of the alignment microscope 17a in the coordinate system of the stage system ( Coordinate)
Is detected. Then, the same operation is performed on the alignment microscope 17b to detect its position. Since the relative positional relationship between the alignment microscopes 17a and 17b and the objective lens 16a is unchanged, the relative positional relationship between the optical axis of the objective lens 16a and the fiducial mark 25 is measured by such an operation. Will be.

The above operation is performed, for example, when the wafer storage cassette 20 is newly set, or when the processing on one side of all the wafers 11 stored in the wafer storage cassette 20 is completed. Done.

Next, the control unit 23 sends a control signal to the wafer transfer arm 24 to start the processing. The wafers 11 stored in the wafer storage cassette 20 with the surface A facing upward are taken out one by one by the wafer transfer arm 24, transferred, and then placed at a predetermined position of the wafer holder 12. At this time, the wafer transfer arm 24 is
Since the reversing operation is not performed, the wafer 11 is placed on the wafer holder 12 while being stored in the wafer storage cassette 20, that is, with the surface A facing upward.

Next, the control unit 23 refers to the signal output from the image processing unit 22, and refers to the θ stage 1
3 and the XY stage 14 are respectively controlled by stepping motors to adjust the relative positional relationship between the wafer 11 and the objective lens 16a.

FIG. 4 shows a display example of an image obtained from the alignment microscope 17a or 17b (similar to the case of alignment between the fiducial mark 25 and the alignment microscopes 17a and 17b). The image signal obtained from the alignment microscope 17a or 17b is superposed on the image signal including the marked line 42 formed electrically or optically in the image processing unit 22, and ITV4
It is supplied to 0 and displayed. The center of the marked line 42 is
Since it coincides with the center of the optical axis of the alignment microscope 17a or 17b, the marked line 42 and the alignment mark 41
Alignment can be performed by adjusting the positional relationship as shown in FIG. That is, the control unit 23
Refers to the signal supplied from the image processing unit 22, as described above, and the alignment mark 41 and the marked line 42.
The θ stage 13 or the XY stage 14 is controlled so that the positional relationship of is as shown in FIG.

When the alignment is completed, the control unit 23 supplies a control signal to the exposure light source 16b to start the processing (exposure) processing of the surface A. Further, at this time, the control unit 23 controls the θ stage 13 or the XY stage 14 as necessary to move the wafer 11 to a desired position.

When the processing of the surface A is completed, the control unit 23 controls the wafer transfer arm 24 to move the wafer 11 to the wafer 11.
Is returned to the previously stored place of the wafer storage cassette 20. This completes the processing of the first wafer 11.

Such processing is performed by the wafer storage cassette 2
This is performed for all the wafers 11 stored in 0. Then, when the processing is completed, the alignment of the fiducial mark 25 and the alignment microscopes 17a and 17b described above is performed again. Then, when the confirmation of the position is completed, the processing of the surface B is started.

That is, the control unit 23 controls the wafer transfer arm 24 to take out the wafer 11 from the wafer storage cassette 20. Then, the wafer 11 is turned over (face B facing upward) and placed at a predetermined position of the wafer holder 12.

At this time, since the surface A of the wafer 11 on which the alignment mark is formed faces the lower side (lower side in the figure), the alignment is performed by the alignment microscopes 17c and 17d. Note that this alignment operation is similar to the above case.

By the above alignment operation, the positions of the pattern formed on the surface A and the pattern formed on the surface B can be accurately matched.

When the alignment is completed, the control unit 23 outputs a control signal to the exposure light source 16b to start the processing for the surface B. When the processing is completed, the wafer 11 is returned to the original position of the wafer storage cassette 20 by the wafer transfer arm 24.

The above operation is repeatedly executed for all the wafers 11 stored in the wafer storage cassette 20. Then, both sides (side A
And the processing of surface B) ends.

According to the above-described embodiment, the positional relationship between the optical axis of the optical system and the stage system can be accurately controlled by the fiducial mark 25.
Both sides of 1 can be processed (exposed) accurately.

FIG. 5 is a diagram showing an example of the configuration of the exposure apparatus of the present invention. In this figure, the same parts as those shown in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted as appropriate.

In this embodiment, the exposure light source 16b, the light quantity control / beam shaping device 16c, the reflecting mirror 16d, and the objective lens 16a are excluded, and the exposure light source 50 and the illumination optical system 5 are excluded.
1, a mask 52, a reduction projection lens 53, and a mask alignment device 54 are newly added. The rest of the configuration is similar to that shown in FIG.

The exposure light source 50 is composed of a mercury lamp, a reflecting mirror, etc., and emits a light beam under the control of the control unit 23. Further, the illumination optical system 51 is configured to control the light amount of the light beam emitted from the exposure light source 50 and to make the light beam uniform. The mask 52 has a pattern to be exposed and is held by the mask alignment device 54. The reduction projection lens 53 focuses the light beam that has passed through the mask 52 on a predetermined region of the wafer 11. In addition, the mask alignment device 54 controls the mask 52 to be arranged at a predetermined position, and makes the mask 52 and the wafer 11 relative to each other with reference to the light beam emitted from the fiducial mark 25. It is designed to finely adjust the position.

Next, the operation of this embodiment will be described.

When the wafer accommodating cassette 20 accommodating the wafer 11 is set at a predetermined place, the control unit 2
Reference numeral 3 controls a stepping motor (not shown) that drives a stage system, observes the fiducial mark 25 with the alignment microscopes 17a and 17b, and the optical axis of the reduction projection lens 53, as in the case of the previously described embodiments. And the positional relationship between the fiducial mark 25 and the fiducial mark 25 are measured.

Subsequently, the mask alignment device 54
The mask 5 is formed by an unillustrated mask alignment optical system.
Alignment is performed so that 2 is at a predetermined position. Then, when the alignment of the mask 52 is completed, the control unit 23 controls a step motor (not shown) of the stage system to move the fiducial mark 25 to a predetermined place.

The fiducial mark 25, which has been moved to a predetermined position, starts irradiation with a light beam (a light beam having a high straightness) by a built-in light source. The light beam emitted from the fiducial mark 25 enters the mask alignment device 54. The mask alignment device 54 uses the incident light beam as a reference to set the mask 5
The positional relationship between 2 and the fiducial mark 25 is calibrated. As a result, the relative positional relationship between the mask 52 and the fiducial mark 25 indicating the reference position of the stage system is calibrated.

Next, the control unit 23 controls the wafer transfer arm 24 to place the wafer 11 on the wafer holder 12 at a predetermined position. Then, as in the case described above, alignment is executed based on the images from the alignment microscopes 17a and 17b, and the wafer 11 is moved to a predetermined position.

When the alignment is completed, the control unit 23 controls the exposure light source 50 to perform the exposure process based on the relative positional relationship between the fiducial mark 25 and the wafer 11 obtained during the alignment process. At this time, the control unit 23 controls the θ stage 13 or the XY stage 14 to move the wafer 11 as necessary.

When the exposure process is completed, the control unit 23 controls the wafer transfer arm 24 to move the wafer 1
1 is returned to the wafer storage cassette 20. Such processing is repeatedly executed for all the wafers 11.

When the exposure of the surface A of all the wafers 11 is completed by the above processing, the exposure of the surface B is next performed.
At this time, for example, when the patterns to be formed on the surface A and the surface B are different, it is necessary to replace the mask 52. When the mask 52 is replaced, the relative position between the new mask 52 and the fiducial mark 25 is adjusted, so that the alignment process of the mask 52 is executed as in the case described above.

Next, the control unit 23 controls the wafer transfer arm 24 to take out the wafer 11 from the wafer storage cassette 20 and invert it (after the surface B is turned up), and then at a predetermined position of the wafer holder 12. To place.

Subsequently, the control unit 23 controls the θ stage 13 or the XY stage 14 on the basis of the image signals output from the alignment microscopes 17c and 17d, as in the case described above, to perform the alignment. Then, when the alignment is completed, an exposure process is performed by the exposure light source 50 based on the relative positional relationship between the wafer 11 and the fiducial mark 25.

When the exposure is completed, the control unit 23
The wafer transfer arm 24 is controlled to return the wafer 11 to the wafer storage cassette 20.

The above operation is repeatedly executed for all the wafers 11 stored in the wafer storage cassette 20. Then, the exposure process is completed.

According to the above-described embodiment, since the exposure can be performed without the mask 52 and the wafer 11 coming into contact with each other, the peeling of the pattern or the mask 52 caused by the adhesion of the resist to the mask 52 occurs. It is possible to prevent deterioration.

Since the relative positional relationship between the mask 52 and the wafer 11 is based on the fiducial mark 25, the shape of the alignment mark formed on the wafer 11 can be freely set. (It does not have to be the same as the alignment mark formed on the mask 52). Therefore, the wafer 1 may be used for other purposes.
For example, since it is possible to use the wafer identification number and the like formed in No. 1, it is possible to further increase the circuit pattern area, and it is possible to omit the process of forming a dedicated alignment. Becomes

[0069]

In the exposure apparatus according to the first aspect of the invention, when the semiconductor substrate is arranged on the stage so that one surface faces the exposure means, the relative position between the fiducial mark and the semiconductor substrate. Measuring the relationship by the first measuring means,
According to the measurement result, the relative positional relationship between the mask and the semiconductor substrate is controlled, and when the semiconductor substrate is arranged on the stage so that the other surface faces the exposure unit, the fiducial mark and the semiconductor Since the relative positional relationship between the substrate and the mask is measured and the relative positional relationship between the mask and the semiconductor substrate is controlled by the second control means according to the measurement result, the relative positional relationship between the semiconductor substrate and the mask is controlled. Since the precise positional relationship can be accurately controlled, the pattern can be accurately formed on the semiconductor substrate.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a configuration of a projection exposure apparatus of the present invention.

FIG. 2 is a diagram showing an example of alignment marks formed on a wafer 11 shown in FIG.

FIG. 3 is a diagram showing a display example when performing alignment by an identification number formed on a wafer 11.

FIG. 4 is a diagram showing a relationship between alignment marks and marked lines.

FIG. 5 is a diagram showing an example of another configuration of the projection exposure apparatus of the present invention.

FIG. 6 is a diagram showing a configuration when a surface A of a wafer 2 is exposed in a conventional exposure apparatus.

FIG. 7 is a diagram showing a configuration for exposing a surface B of a wafer 2 in a conventional exposure apparatus.

FIG. 8 is a three-dimensional view showing an example of the configuration of a conventional exposure apparatus.

FIG. 9 is a diagram showing an example of the positional relationship of alignment marks observed in a conventional exposure apparatus.

[Explanation of symbols]

Reference Signs List 11 wafer 12 wafer holder 13 θ stage 14 XY stage (first control means, second control means) 16b exposure light source (exposure means) 17a to 17d alignment microscope (first measurement means, second measurement means, detection means) ) 20 wafer storage cassette 22 image processing unit (detection means) 23 control unit (first control means, second control means) 24 wafer transfer arm 42 mark line 50 exposure light source (exposure means) 51 illumination optical system 52 mask

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication H01L 21/30 507A 510

Claims (5)

[Claims] 1. An exposure apparatus for performing exposure by controlling a relative positional relationship between a semiconductor substrate and a mask, wherein an exposure means for exposing the semiconductor substrate through the mask, and the semiconductor substrate are arranged. A stage, a fiducial mark indicating the reference position of the stage, and the fiducial mark and the fiducial mark when the semiconductor substrate is arranged on the stage so that one surface faces the exposure unit. First measuring means for measuring the relative positional relationship between the semiconductor substrate and first control for controlling the relative positional relationship between the mask and the semiconductor substrate according to the measurement result of the first measuring means. Means, and when the semiconductor substrate is arranged on the stage so that the other surface faces the exposure means, the relative position between the fiducial mark and the semiconductor substrate. Second measuring means for measuring a relative positional relationship, and second control means for controlling a relative positional relationship between the mask and the semiconductor substrate according to a measurement result of the second measuring means. An exposure apparatus characterized by the above. 2. The exposure apparatus according to claim 1, wherein the exposure unit performs projection exposure on the semiconductor substrate. 3. The first and second measuring means optically measure a relative position between the fiducial mark and the semiconductor substrate, and the first measuring means and the second measuring means include: The exposure apparatus according to claim 1, wherein the optical axes of the optical systems coincide with each other. 4. The first and second measuring means optically measure a relative position between the fiducial mark and the semiconductor substrate, and the first and second measuring means include: The exposure apparatus according to claim 1 or 2, further comprising detection means for detecting a shift of an optical axis of each optical system. 5. The relative distance between the fiducial mark and the semiconductor is defined by the first and second measuring means based on a character or a figure formed at a predetermined position on the semiconductor substrate. The exposure apparatus according to claim 1, wherein a positional relationship is measured.