JPH06163358A - Exposure method and aligner - Google Patents

Abstract

(57) [Summary] [Object] To improve the alignment accuracy between a projected image of a first pattern region having only a mask pattern and a projected image of a second pattern region having a phase shift pattern. A mask 10 provided with a first pattern region having only a mask pattern and a second pattern region having a phase shift pattern is used to superimpose each projected image of each pattern region on the semiconductor wafer 3 and Prior to transferring the predetermined pattern onto the wafer, when aligning the patterns in the respective pattern areas, the position of the sensor 17 installed at a predetermined position in the vicinity of the semiconductor wafer 3 by the alignment mark composed of the mask pattern on the mask 10. Is detected and the projected image of the alignment mark having the phase shift pattern on the mask 10 is detected by the sensor 17, then the alignment error between the phase shift pattern and the mask pattern is measured based on the detection result, and the measurement result is Based on this, alignment correction between both patterns is performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure technique, and more particularly to a technique effectively applied to transfer of a circuit pattern using a phase shift mask in a manufacturing process of a semiconductor integrated circuit device.

[0002]

2. Description of the Related Art As semiconductor integrated circuits are highly integrated and the design rules of circuit elements and wiring are on the order of submicrons, circuit patterns on a mask substrate are radiated using light such as i-line (wavelength 365 nm). In the photolithography process for transferring a semiconductor wafer onto a semiconductor wafer, a decrease in accuracy of a circuit pattern transferred onto the semiconductor wafer becomes a serious problem.

As a means for improving this problem, there is a phase shift technique for preventing the contrast of the projected image from being lowered by changing the phase of the light transmitted through the mask substrate.

For example, in Japanese Examined Patent Publication No. 62-59296, a transparent film is provided on one of a pair of light-transmitting regions sandwiching a light-shielding region, and a transparent film is placed between the light transmitted through the two light-transmitting regions during exposure. A phase shift technique is disclosed in which a phase difference is generated so that the interference light weakens each other at a portion that should originally be a light shielding region on a semiconductor wafer.

Further, in Japanese Patent Laid-Open No. 2-140743, a transparent film having a predetermined film thickness is provided in a part of a light-transmitting region of a mask, and each of a region with a transparent film and a region without a transparent film during exposure is provided. A phase shift technique has been disclosed in which a pattern is transferred to a boundary portion between a region with a transparent film and a region without the transparent film by causing a phase difference in transmitted light.

Further, in Japanese Patent Application No. 3-255077 filed by the present inventor, a mask substrate having a shifter pattern and a mask substrate having only a mask pattern consisting of a light shielding portion and a light transmitting portion are described. A phase shift technique is disclosed in which projected images of transmitted light are superimposed on a sample and a predetermined pattern is transferred onto the sample.

As a method of aligning with a base pattern on a semiconductor wafer by using a shifter pattern, for example, "SPI-E, Optical Laser Microlithography Part 3, Volume 1264 (SPIE
Optical / Laser Microlithogrraphy III Vol 126
4) ”P194 to P202.

[0008]

However, in the conventional technique described in Japanese Patent Laid-Open No. 3-255077, the pattern transferred by the light transmitted through the mask substrate on which the shifter pattern is formed, and the mask pattern. There is a problem that an error occurs in the alignment with the pattern transferred by the light transmitted through the mask substrate on which only the mask is formed.

The present invention has been made in view of the above problems, and an object thereof is a pattern transferred by light transmitted through a pattern region in which only a shifter pattern is formed and a pattern in which only a mask pattern is formed. An object of the present invention is to provide an exposure technique capable of improving the alignment accuracy with the pattern transferred by the light transmitted through the area.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0011]

Among the inventions disclosed in the present application, a typical one will be briefly described as follows.
It is as follows.

That is, the invention according to claim 1 uses a mask substrate provided with a first pattern region having only a mask pattern and a second pattern region having a shifter pattern, wherein the first pattern region and the second pattern region are used. When aligning the pattern of the first pattern area and the pattern of the second pattern area prior to transferring a predetermined pattern onto the sample by superimposing the respective projected images of A step of detecting a position of a sensor portion installed at a predetermined position near the sample by a first alignment mark formed of a mask pattern on the mask substrate, and a second position having a shifter pattern on the mask substrate. The step of detecting the projected image of the alignment mark by the sensor section, the position detection result of the sensor section, and the second position adjustment. A step of measuring the alignment error between the shifter pattern and the mask pattern based on the detection result of the projected image of the mark, and the alignment between the mask pattern and the shifter pattern is corrected based on the measurement result. And an exposure method including steps.

[0013]

According to the above means, the position of the sensor portion is measured by the transmitted light of the first alignment mark composed of the mask pattern, while the projected image of the second alignment mark having the shifter pattern is detected by the sensor portion. , The alignment error between the mask pattern and the shifter pattern is measured, and the alignment between the mask pattern and the shifter pattern is corrected based on the measurement result. It is possible to favorably align the pattern area with the shifter pattern.

[0014]

Embodiment 1 FIG. 1 is an explanatory view of an optical system of an exposure apparatus which is an embodiment of the present invention, FIG. 2 is a plan view of a mask which is an embodiment of the present invention, and FIG. 3 is a schematic view of the mask of FIG. 3 is a plan view of the mask of FIG. 3, FIG. 5 is a graph showing the amplitude of light immediately after passing through the masks of FIGS. 3 and 4, and FIG. FIG. 7 is a graph showing the intensity of light on the sample, FIG. 7 is a plan view of the main part of the mask of FIG.
8 is a sectional view of the mask of FIG. 7, FIG. 9 is a graph showing the amplitude of light immediately after passing through the masks of FIGS. 7 and 8, and FIG.
0 is a graph showing the intensity of light transmitted through the masks of FIGS. 7 and 8 on the sample, and FIG. 11 is a graph showing the intensity of combined light obtained when the transmitted lights of FIGS. 6 and 10 are overlapped. FIGS. 12 to 14 are plan views of the alignment mark formed in the alignment mark area, FIG. 15 is an overall plan view of the sample, FIG. 16 is an explanatory diagram of the exposure method of the first embodiment, and FIG. 17 is a mask. FIG. 18 is a graph showing a detection signal waveform of an alignment mark composed only of patterns, and FIG. 18 is a graph showing a detection signal waveform of an alignment mark having a shifter pattern.

The exposure apparatus 1 of the first embodiment shown in FIG. 1 is a reduction projection exposure apparatus used in the exposure process of a semiconductor integrated circuit device, for example.

A first plane mirror 4a, a shutter 5, an aperture 6, a shortcut filter 7, a second plane mirror 4b, a mask blind 8 and a condenser are provided on the optical path connecting the light source 2 of the exposure apparatus 1 and the semiconductor wafer (sample) 3. Lens 9,
A mask 10, a mask moving table 11, and a reduction projection lens 12 are arranged.

The light source 2 is, for example, i-line (wavelength 365 nm)
It is a high pressure mercury lamp that emits light such as. Also,
The semiconductor wafer 3 is made of, for example, silicon (Si) single crystal, and a photoresist (not shown) sensitive to light is spin-coated on its main surface. The mask blind 8 is a component for selectively irradiating two pattern areas, which will be described later, formed on the mask 10 with light.

An alignment mark detector 14 is arranged between the condenser lens 9 and the mask 10. The alignment mark detection unit 14 is provided on the mask 10.
It is a detection unit used when aligning each pattern in one pattern area, and has a sensor 14a and a reflecting mirror 14b that guides the reflected light from the semiconductor wafer 3 to the sensor 14a.

The sensor 14a is electrically connected to a position data generating circuit (measuring means) 15. The position data creation circuit 15 is a circuit that creates the position data of the alignment mark based on the detection signal detected by the sensor 14a.

The position data creating circuit 15 is electrically connected to the error amount measuring circuit (measuring means) 16. The error amount measurement circuit 16 is a circuit that measures the alignment error amount of each pattern of the two pattern regions formed on the mask 10 based on the position data calculated by the position data creation circuit 15.

In the first embodiment, the sensor 17 is arranged on the stage 13 on which the semiconductor wafer 3 is mounted. The sensor 17 is a component that detects a transfer position of a projected image of an alignment mark (not shown in FIG. 1) described later formed on the mask 10 and serves as a reference for alignment.

The sensor 17 is installed at a predetermined position on the stage 13 and also serves as an alignment mark used for aligning each pattern in two pattern regions (not shown in FIG. 1 to be described later).

The stage 13 is composed of a Y-axis moving base 13
The y-axis moving table 13x, the Z-axis moving table 13z, and the wafer suction table 13w are installed in this order from the bottom.

The mask 10 is a reticle on which an original image five times as large as an actual size semiconductor integrated circuit pattern is formed, for example, for transferring a predetermined semiconductor integrated circuit pattern onto the semiconductor wafer 3 in a manufacturing process of a semiconductor manufacturing apparatus. Mask 1
A plan view of No. 0 is shown in FIG.

A first pattern region 18a and a second pattern region 1 are formed on the mask substrate 10a forming the mask 10.
8b and are arranged. The mask substrate 10a forming the mask 10 is made of, for example, transparent synthetic quartz glass having a refractive index of 1.47.

A light shielding pattern 19 for mask blind is formed around the first pattern area 18a and the second pattern area 18b. The width of the light shielding pattern 19 is, for example, about 0.5 to 10 mm.

Alignment mark areas A to C are arranged at predetermined positions around the light shielding pattern 19. In the alignment mark area A, alignment marks in the Y-axis direction described later are formed. In the alignment mark area B,
An alignment mark in the X-axis direction described later is formed.
Further, in the alignment mark area C, alignment marks in the rotation direction described later are formed.

In the first pattern area 18a, as shown in FIGS.
As shown in, only the mask pattern 20 including, for example, the light shielding portion 20n and the light transmitting portion 20p is formed. The light shielding portion 20n is made of a metal such as chromium (Cr).

As shown in FIG. 5, the amplitude of the light transmitted through the first pattern area 18a becomes zero in the area corresponding to the light shielding portion 20n. Further, when the transmitted light is transferred to the semiconductor wafer 3 through the reduction projection optical system, the intensity of the light seems to have dropped as shown in FIG. 6 at the boundary between the light shielding portion 20n and the light transmitting portion 20p. The light intensity waveform becomes

On the other hand, in the second pattern region 18b, as shown in FIGS. 7 and 8, a shifter pattern 21 is arranged at a predetermined position of the light transmitting portion 20p.

The shifter pattern 21 is a member that causes a phase difference between the light transmitted through the region where the shifter pattern 21 exists and the light transmitted through the region where the shifter pattern 21 does not exist in the light transmitting portion 20p. , Eg SOG
It is made of a transparent film such as (Spin On Glass). Thereby, the diffraction projection image is transferred as described below.

The film thickness of the shifter pattern 21 is d = λ / 2, where λ is the wavelength of transmitted light and n is the refractive index of the transparent film.
The relationship of (n-1) is satisfied. For example, the wavelength λ of light used for pattern exposure is 0.365 μm (i
Line) and the refractive index n of the transparent film is 1.5, the thickness of the transparent film may be about 0.37 μm.

The diffraction projection image of the light transmitted through the second pattern area 18b is the first pattern area 18 described above.
It is overlapped with the light shielding portion 20n of a.

Here, the light transmitting portion 20p of the second pattern region 18b is patterned so that the length in the Y-axis direction is longer than that of the light shielding portion 20n of the first pattern region 18a. This is because the contrast of the diffracted projection image is reduced at the peripheral portion in the Y-axis direction of the light shielding portion 20n in FIG. 3 unless it is performed so that it is suppressed.

As shown in FIG. 9, the amplitude of the light immediately after passing through the second pattern region 18b is inverted between the light passing through the shifter pattern 21 and the light not passing through the shifter pattern 21. There is.

Further, the transmitted light is passed through a reduction projection optical system,
When the light is transferred onto the semiconductor wafer 3, the light intensity waveform has a steep dent at the boundary between the region with the shifter pattern 21 and the region without the shifter pattern 21, as shown in FIG.

As a result, the diffraction projection image due to the phase difference of the transmitted light is transferred onto the semiconductor wafer 3. This diffraction projection image becomes an image of an extremely fine line with good contrast if the coherency of the light used is increased.

Further, FIG. 11 shows intensity waveforms of light obtained by synthesizing light transmitted through each of the first pattern region 18a and the second pattern region 18b. That is, by superimposing two sets of light on each other as shown in FIG. 11 and irradiating the semiconductor wafer 3, it is possible to create an image of an extremely fine line with a high contrast at a predetermined position.

Next, the alignment mark area A shown in FIG.
12 to 13 will be described with reference to FIGS.

In the alignment mark area A, as shown in FIG. 12, two kinds of alignment marks (second alignment marks) 22a and alignment marks (first alignment marks) 22b are formed. One alignment mark 2
2a is composed of a rectangular light-transmitting portion 20p ₁ and a shifter pattern 21 on the upper portion thereof. The shifter pattern 21 is formed such that one side thereof is arranged substantially at the center of the short side of the light transmitting portion 20p ₁ . In the case of such alignment marks 22a and 22b, the shifter pattern 21
Since a steep detection waveform can be obtained by operating the phase of the light by, the detection accuracy can be improved.

[0041] The other alignment mark 22b is composed of only rectangular three translucent portions 20p ₂ ~20p _4, no shifter pattern 21 is formed. The broken line indicates the alignment mark formed on the semiconductor wafer 3.

Also in the alignment mark area B, FIG.
, Two types of alignment marks 22a, 22b
Are formed. Also in the alignment mark area C, as shown in FIG.
2a and 22b are formed.

The mask 10 as described above may be manufactured, for example, as follows. First, C on the mask substrate 10a
A metal film such as r is deposited by a sputtering method or the like.

Then, on the metal film, for example, about 0.5 μm is formed.
After applying an electron beam resist film having a thickness of about m, pre-baking is performed.

After that, the electron beam resist film is irradiated with an electron beam by using an electron beam drawing apparatus or the like. The electron beam drawing apparatus uses an electron beam as a mask substrate 1 according to pattern data in which the position coordinates, shape, etc. of a semiconductor integrated circuit pattern are stored.
The electron beam resist film on 0a is irradiated.

Next, after the exposed portion of the electron beam resist film is removed by a predetermined developing solution, the metal film exposed from the electron beam resist film is removed by etching by a wet etching method or the like to form a pattern in a predetermined shape.

Subsequently, after removing the electron beam resist film with a resist stripping solution, the mask substrate 10a is washed.
Thereby, the light-shielding portion 20n and the light-transmitting portion 20p having a predetermined shape
A mask pattern 20 composed of is formed.

After that, to form the shifter pattern 21 for inverting the phase of light on the mask substrate 10a, for example, the following process is performed.

First, a transparent film made of SOG or the like is applied on the mask substrate 10a on which the mask pattern 20 is formed, and then high temperature baking is performed. At that time, the thickness d of the transparent film is d = λ / 2, where λ is the wavelength of transmitted light and n is the refractive index of the transparent film.
(N-1) or this approximate value.

Then, in the same manner as described above, the transparent film is processed by using an electron beam lithography technique or the like so that only a necessary portion remains. In this way, the shifter pattern 21 is formed on the mask substrate 10a to form the mask 1
0 is produced.

Next, the exposure method of this embodiment will be described with reference to FIGS.
Explained by.

The exposure method of the practical example 1 is the same as the mask 1 described above.
At the time of exposure using 0, the mask blind 8 sequentially selects and exposes the first pattern region 18a and the second pattern region 18b.

Then, only the first pattern region 18a is transferred onto the semiconductor wafer 3, or the first pattern region 18a is transferred.
The transmitted light of each of a and the second pattern region 18b is superimposed and transferred on the semiconductor wafer 3. FIG. 15 shows the semiconductor wafer 3.

A rectangular broken line region D is a region in which only the first pattern region 18a is transferred. The rectangular solid line area E is an area in which the transmitted light of each of the first pattern area 18a and the second pattern area 18b is transferred onto the semiconductor wafer 3 in an overlapping manner.

At this time, prior to the superposition, the position errors of the patterns of the first pattern area 18a and the second pattern area 18b are detected, and those position errors are corrected.

With this method, when the mask 10 is manufactured, the mask pattern 2 including the shifter pattern 21 for changing the phase of transmitted light and the light transmitting portion 20p and the light shielding portion 20n.
Even if a relative position error occurs with respect to 0, it is possible to correct the alignment of the patterns 20 and 21 during the exposure processing.

Here, a method of correcting the alignment will be described with reference to FIG.
~ It demonstrates by FIG.

First, as shown in FIG. 16, the exposure light L is applied to the mask 10. At this time, the light transmitted through the alignment mark areas A to C formed on the mask 10 is applied to the sensor 17 on the stage 13 through the reduction projection lens 12.

At this time, the projected image of the light transmitted through the alignment mark 22b formed only by the mask pattern 20 is
It is detected by the sensor 14a through the alignment mark 23 for alignment of the mask itself, which is reflected from the sensor 17 and is formed on the mask 10. In addition, this sensor 14a
Is also used when detecting the alignment mark 24 on the semiconductor wafer 3.

At this time, the detection signal waveform detected by the sensor 14a has a peak value at a predetermined detection position, as shown in FIG.

On the other hand, the projected image of the light transmitted through the alignment mark 22a formed with the shifter pattern 21 is detected by the sensor 17 on the stage 13. At this time, the detection signal waveform detected by the sensor 17 is a waveform having a steep dent in the center of the waveform, as shown in FIG.

Then, in the error amount calculation circuit 16,
Based on the difference between the center positions of the above-mentioned two detection signal waveforms, the mask pattern 20 in the first pattern region 18a
And an alignment error amount F (see FIG. 17) with the shifter pattern 21 in the second pattern area 18b is calculated.

Then, based on the calculation result, the stage position on which the semiconductor wafer 3 is mounted is converted by laser length measurement, whereby the mask pattern 20 in the first pattern region 18a and the shifter pattern in the second pattern region 18b are converted. Two
Correct the position error with 1.

As described above, in the first embodiment, the following effects can be obtained.

(1). The transmitted light of each of the first pattern region 18a in which only the mask pattern 20 is formed and the second pattern region 18b in which the shifter pattern 21 is formed is superimposed on the semiconductor wafer 3 to form a semiconductor. Prior to the exposure process for transferring a predetermined pattern to the photoresist on the wafer 3, the position of the sensor 17 on the stage 13 is detected by the alignment mark 22b including only the mask pattern 20, and the alignment having the shifter pattern 21 is performed. The projected image of the mark 22a is detected by the sensor 17, and the first pattern region 18 is detected based on the detection signals of both.
a and the second pattern area 18b, the amount of alignment error is measured, and the alignment of both areas is corrected based on the measurement result, so that the mask pattern 20 and the second pattern area of the first pattern area 18a are It is possible to improve the alignment accuracy with the shifter pattern 21 of 18b.

(2). Due to the above (1), good alignment can be achieved, so that the reliability and yield of the semiconductor integrated circuit device can be improved.

[0067]

Embodiment 2 FIGS. 19 and 20 are explanatory views of an exposure apparatus which is another embodiment of the present invention.

In the exposure apparatus 1 of the second embodiment shown in FIGS. 19 and 20, the condenser lens 9 and the mask 1 are used.
An alignment optical system 25 is arranged between the position 0 and 0.

The alignment optical system 25 includes a laser light emitting section 25a for emitting laser light and the mask 1 for the laser light.
It has a reflecting mirror 25b for leading to 0 and a sensor 25c for detecting the light reflected from the semiconductor wafer 3 when the semiconductor wafer 3 is irradiated with the laser light.

A wafer mark detecting optical system 26 is arranged between the mask 10 and the reduction projection lens 12. The wafer mark detection optical system 26 includes the laser light emitting unit 2
6a and the reflecting mirror 26b. The emitted light from the laser light emitting portion 26a is guided to the reduction projection lens 12 via the reflecting mirror 26b, and is irradiated onto the semiconductor wafer 3. Then, the reflected light is applied to the sensor 25c of the alignment optical system 25 via the reduction projection lens 12 and the mask 10.

Furthermore, the exposure apparatus 1 of the second embodiment has a wafer alignment optical system 27. This is an alignment mark detector used when aligning the reduction projection optical system and the semiconductor wafer 3. Wafer alignment optical system 2
7 has a laser beam emitting portion 27a, a sensor 27b, and a lens 27c. The light emitted from the laser light emitting section 27a is applied to the semiconductor wafer 3 via the lens 27c. And the reflected light is
The sensor 27b is illuminated via the lens 27c.

In the exposure apparatus according to the second embodiment, the alignment optical system 25 allows the first pattern area 1
8a and the second pattern area 18b, a relative position error is calculated, and the mask pattern 20 of the first pattern area 18a and the second pattern area 18 are calculated based on the calculated value.
The position error with the shifter pattern 21 of b is corrected. This makes it possible to obtain the same effects as those of the first embodiment.

[0073]

[Third Embodiment] FIG. 21 is an explanatory view of an exposure apparatus according to another embodiment of the present invention.

The exposure apparatus 1 of the third embodiment shown in FIG. 21 has a structure capable of performing exposure processing using two masks 10, 10. The description of Japanese Patent Application No. 3-255077 will be made a part of the present application for the third embodiment.

The mask pattern 2 is formed on one mask 10.
Only 0 (see FIG. 3) is formed. In addition, the alignment mark 22b (FIG.
(See) is formed. That is, the first and second embodiments
Corresponds to the first pattern area 18a.

A shifter pattern 21 is formed on the other mask 10. In addition, the shifter pattern 21
An alignment mark 22a having is formed. That is, it corresponds to the second pattern region 18b in the first and second embodiments.

The reflecting mirror 28a is a component for causing the light emitted from the light source 2 and incident through the beam expander 29 to be incident on the mask 10. Reflector 28b
Is a component for making the light incident through the mask 10 and the lens 30 incident on the semiconductor wafer 3 through the objective lens 31.

In the third embodiment, for example, both masks 10 and 10 are simultaneously irradiated with exposure light, and projected images of the light transmitted through both masks 10 and 10 are superimposed on the semiconductor wafer 3. A predetermined pattern is transferred.

Prior to the exposure processing, the alignment error of the masks 10, 10 is measured by the sensor 17 on the stage 13 as in the first and second embodiments, and the masks 10, 10 are measured based on the measurement results. The alignment correction of the projected image of each light transmitted through 10 is performed. This makes it possible to obtain the same effects as those of the first and second embodiments.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above-mentioned first to third embodiments, and various modifications can be made without departing from the spirit of the invention. Needless to say, it can be changed.

For example, in the above-mentioned first to third embodiments, the case where the exposure light is the i-line has been described, but the present invention is not limited to this and various modifications are possible, for example, the G-line may be used.

In the above description, the case where the invention made by the present inventor is mainly applied to the exposure method of the semiconductor integrated circuit device which is the background field of application has been described, but the invention is not limited to this and various modifications can be made. It is also possible to apply it to an exposure method performed in the manufacture of a mask or a liquid crystal screen, for example.

[0083]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.
It is as follows.

That is, according to the invention of claim 1,
While the position of the sensor unit is measured by the transmitted light of the first alignment mark composed of the mask pattern, the projected image of the second alignment mark composed of the shifter pattern is detected by the sensor unit to align the mask pattern and the shifter pattern. By measuring the error and correcting the alignment between the mask pattern in the first pattern region and the shifter pattern in the second pattern region based on the measurement result, the mask pattern in the first pattern region, It is possible to favorably align the two pattern areas with the phase shift pattern.

Therefore, it is possible to improve the alignment accuracy between the projected image of the first pattern area in which only the mask pattern is formed and the projected image of the second pattern area in which only the shifter pattern is formed.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an optical system of an exposure apparatus that is an embodiment of the present invention.

FIG. 2 is a plan view of a mask that is an embodiment of the present invention.

FIG. 3 is a plan view of an essential part of the mask shown in FIG.

4 is a cross-sectional view of the mask of FIG.

5 is a graph showing the amplitude of light immediately after passing through the masks of FIGS. 3 and 4. FIG.

6 is a graph showing a light intensity on a sample of light transmitted through the masks of FIGS. 3 and 4. FIG.

FIG. 7 is a plan view of a main part of the mask shown in FIG.

8 is a cross-sectional view of the mask of FIG.

9 is a graph showing the amplitude of light immediately after passing through the masks of FIGS. 7 and 8. FIG.

10 is a graph showing the light intensity on the sample of the light transmitted through the masks of FIGS. 7 and 8. FIG.

FIG. 11 is a graph showing the intensity of combined light obtained when the transmitted lights of FIGS. 6 and 10 are overlapped.

FIG. 12 is a plan view of an alignment mark formed in an alignment mark area.

FIG. 13 is a plan view of an alignment mark formed in an alignment mark area.

FIG. 14 is a plan view of an alignment mark formed in an alignment mark area.

FIG. 15 is an overall plan view of a sample.

FIG. 16 is an explanatory diagram of an exposure method according to the first embodiment.

FIG. 17 is a graph showing a detection signal waveform of an alignment mark composed of only a mask pattern.

FIG. 18 is a graph showing a detection signal waveform of an alignment mark having a shifter pattern.

FIG. 19 is an explanatory diagram of an exposure apparatus that is another embodiment of the present invention.

FIG. 20 is an explanatory diagram of an exposure apparatus that is another embodiment of the present invention.

FIG. 21 is an explanatory diagram of an exposure apparatus that is another embodiment of the present invention.

[Explanation of symbols]

1 exposure apparatus 2 light source 3 semiconductor wafer (sample) 4a first plane mirror 4b second plane mirror 5 shutter 6 aperture 7 shortcut filter 8 mask blind 9 condenser lens 10 mask 10a mask substrate 11 mask moving table 12 reduction projection lens 13 stage 13x X axis Moving table 13y Y-axis moving table 13z Z-axis moving table 13w Wafer suction table 14 Positioning mark detecting section 14a Sensor 14b Reflecting mirror 15 Position data creating circuit (measuring means) 16 Error amount measuring circuit (measuring means) 17 Sensor 18a 1st pattern area 18b second pattern region 19 shielding patterns 20 mask patterns 20p, 20p ₁ ~20p ₄ translucent portion 20n shielding portion 21 phase shift pattern 22a alignment mark (second alignment mark) 22b alignment marks (first position if 23) Alignment mark 24 Alignment mark 25 Alignment optical system 25a Laser light emitting part 25b Reflecting mirror 25c Sensor 26 Wafer mark detecting optical system 26a Laser light emitting part 26b Reflecting mirror 27 Wafer aligning optical system 27a Laser light emitting part 27b sensor 27c lens 28a, 28b reflecting mirror 29 beam expander 30 lens 31 objective lens A to C alignment mark area D, E area F error amount L exposure light

Claims (3)

[Claims] 1. A sample obtained by projecting each of the first pattern region and the second pattern region using a mask substrate having a first pattern region having only a mask pattern and a second pattern region having a phase shift pattern. On the mask substrate, when aligning the pattern of the first pattern area and the pattern of the second pattern area prior to transferring the predetermined pattern on the sample by superimposing them on each other. First consisting of mask pattern
The step of detecting the position of the sensor unit installed at a predetermined position near the sample by the alignment mark, and the projected image of the second alignment mark having the phase shift pattern on the mask substrate are detected by the sensor unit. And a step of measuring an alignment error between the phase shift pattern and the mask pattern based on the position detection result of the sensor unit and the detection result of the projected image of the second alignment mark.
And a step of correcting the alignment between the mask pattern and the phase shift pattern based on the measurement result. 2. A sample obtained by projecting each of the first pattern region and the second pattern region using a mask substrate having a first pattern region having only a mask pattern and a second pattern region having a phase shift pattern. On the mask substrate, when aligning the pattern of the first pattern area and the pattern of the second pattern area prior to transferring the predetermined pattern onto the sample by superimposing them on each other. First consisting of mask pattern
The step of detecting the position of the sensor unit installed at a predetermined position near the sample by the alignment mark, and the projected image of the second alignment mark composed of the phase shift pattern on the mask substrate are detected by the sensor unit And a step of measuring an alignment error between the phase shift pattern and the mask pattern based on the position detection result of the sensor unit and the detection result of the projected image of the second alignment mark.
And a step of correcting the alignment between the mask pattern and the phase shift pattern based on the measurement result and the measurement result of the temporal change of the detected position. 3. An exposure light source for irradiating a sample mounted on a stage with exposure light, and a first pattern detachably installed between the exposure light source and the sample and having only a mask pattern. An area and a mask substrate having a second pattern area having a phase shift pattern,
A mask blind disposed between the exposure light source and the mask substrate and selectively irradiating the first pattern region and the second pattern region with light, respectively.
A sensor which is installed at a predetermined position on the stage and whose position is detected by a first alignment mark composed of the mask pattern and which detects a projected image of a second alignment mark composed of the phase shift pattern. Of the mask pattern and the phase shift pattern based on the data of the position of the sensor unit detected by the first alignment mark and the data of the projected image of the second alignment mark detected by the sensor unit. An exposure apparatus comprising: a measuring unit that measures a positioning error.