JP2000040662A - Aligner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a throughput by performing exposing and alignment information detecting operations performed on two sheets of substrates to be exposed. SOLUTION: When a mask pattern is exposed on the substrates W1 (W2) on one side which are arranged on and retained by a substrate stage ST, an optical system PL, the first and the second alignment optical systems AA1a, AA1b, AA2a and AA2b are arranged in such a manner that the detection of the alignment information of the other substrates W2 (W1) is performed in parallel with the above-mentioned exposure. The positioning when a mask pattern is exposed on a substrate is performed using the alignment information obtained when the exposing operation is performed. Also, the position detecting means 11 and 12 of the substrate stage ST used for positioning on the exposure position, and the position detecting means 11, 13 (11, 14) of the substrate stage ST to be used for detection of alignment information on the alignment position are arranged in such a manner that the Abbe error to exposure position and alignment position becomes almost zero.

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 more particularly to a projection exposure apparatus improved so that exposure and alignment information detection are performed in parallel on two substrates to be exposed so as to improve throughput. It is.

[0002]

2. Description of the Related Art FIG. 11 shows a schematic configuration of a conventional reduction projection exposure apparatus, where R is a mask or reticle (hereinafter referred to as a reticle) on which an exposure pattern is formed, and W is a substrate to be exposed such as a wafer. In addition, the wafer W is held on a stage ST that moves in the XY plane. A projection optical system PL exposes the wafer W by reducing the exposure pattern of the reticle R to, for example, 1/5. Reference numeral 10 denotes a well-known off-axis alignment system, which separates a light beam emitted from a laser light source 11 into an X-axis alignment light beam L11, a Y-axis alignment light beam L12, and a θ rotation axis alignment light beam L13 by an alignment optical system 12. To enter the mark on the wafer W. Then, the light reflected from the wafer W is received by the light receiving device 13 to detect alignment information in the X-axis direction, alignment information in the Y-axis direction, and alignment information in the θ rotation direction. In this way, the XY position of the XY stage ST and the θ rotation position of the wafer stage (not shown) are controlled based on the alignment information obtained from the off-axis alignment system 10, and so-called rough alignment is performed.

[0003] Reference numeral 20 denotes a well-known TTL (Through The Lens).
An alignment system is disclosed in, for example, Japanese Patent Application Laid-Open No. 60-18684.
As disclosed in Japanese Patent Laid-Open Publication No. 5 (1999) -2005, a light beam emitted from a laser light source 21 is separated into an X-axis alignment light beam L21 and a Y-axis alignment light beam L22 by an alignment optical system 22, and is transmitted via a projection optical system PL. The light is incident on the alignment mark of the wafer W, and the reflected light is received by a light receiving device (not shown) to detect the X-axis alignment information and the Y-axis alignment information. In this way, so-called fine alignment is performed for each exposure area on the wafer W based on the alignment information obtained from the TTL alignment system 20.

In such a conventional reduction projection exposure apparatus, an exposure pattern of a reticle R is exposed to a plurality of exposure regions regularly arranged on one wafer W as follows. . The wafer W is loaded on the stage ST, and rough alignment is first performed on the loaded wafer W by the off-axis alignment system 10 to position the wafer. Next, fine alignment is performed by the TTL alignment system 20 on the wafer W on which the rough alignment has been completed. In the fine alignment, first, an alignment mark of one exposure area in the wafer W is observed by the TTL alignment optical system 20, alignment is performed on the exposure area, and then the exposure pattern of the reticle R is exposed.
After the exposure of the one exposure area is completed, the next exposure area is directly opposed to the projection optical system PL by the stage ST, and the exposure area is aligned by the TTL alignment system 20 to expose the exposure pattern. The alignment step and the exposure step are performed on all the exposure regions on the wafer, and the exposure of one wafer is completed. Such an exposure method is called a die-by-die alignment method.

On the other hand, there is also known an exposure apparatus which employs a method called an enhancement global alignment (hereinafter referred to as an EGA method) for such a die-by-die alignment method. This EGA system is, for example, disclosed in Japanese Patent Application Laid-Open No. 61-44429.
Alignment information is detected for some representative exposure areas of the entire exposure area on a single wafer, and the detection results are statistically processed to predict linear or non-linear displacements for the entire exposure area. This is to improve the throughput by shortening the process time for aligning the exposure area with the projection optical system.

[0006]

However, in the conventional reduction projection exposure apparatus using the former die-by-die alignment method, the exposure pattern of the reticle R is exposed on one exposure area of the wafer W. An alignment step is indispensable in advance, and it takes time to perform exposure processing on one wafer W, and the throughput is poor. On the other hand, in the latter EGA method,
It is essential to detect alignment information of several representative points prior to exposure.Furthermore, if the number of representative points is small, the reliability is low, and if the number of representative points is increased, the reliability is improved. And the throughput is reduced.

SUMMARY OF THE INVENTION An object of the present invention is to provide a projection exposure apparatus in which exposure and alignment information detection are performed in parallel on two substrates to be exposed to improve throughput.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to FIGS. 1 and 2 showing an embodiment. An exposure apparatus according to the present invention holds a first substrate W1 and a second substrate W2. A substrate stage ST that moves two-dimensionally, and a first position detection that is arranged so that Abbe error is substantially zero with respect to the exposure position of the pattern of the mask R, and detects a two-dimensional position of the substrate stage ST. Means 11 and 12 are provided. Further, mark observing means AA for observing alignment marks WMa, WMb (FIG. 3) formed on first substrate W1.
1a and AA1b. This first mark observation means A
A1a and AA1b have a predetermined positional relationship with the exposure position such that the alignment marks WMa and WMb of the first substrate W1 substantially coincide with the mark observation position when the center point of the second substrate W2 is made to coincide with the exposure position. It is arranged in. Further, the second position detecting means 11 is arranged such that the Abbe error is substantially zero with respect to the mark observing positions of the first mark observing means AA1a and AA1b, and detects the two-dimensional position of the substrate stage ST. , 13 are provided. Then, the mark observing means AA2a, A for observing the alignment marks WMa, WMb formed on the second substrate W2.
A2b is also provided. This second mark observation means AA2
a, AA2b are the alignment marks WM of the second substrate W2 when the center point of the first substrate W1 is matched with the exposure position.
a and WMb are arranged in a predetermined positional relationship with respect to the exposure position so that they substantially coincide with the mark observation position. Further, the exposure apparatus includes second mark observing means AA2a and AA2b.
, And third position detecting means 11 and 14 for detecting the two-dimensional position of the substrate stage ST and the first and second mark observing means (AA1a, AA1b), (AA2a, AA2b)
Alignment position detecting means DT1 and DT2 for detecting the position of each alignment mark when observing the alignment marks WMa and WMb of the first and second wafers W1 and W2, respectively, and the first position detecting means 1
The first and second detection results are respectively associated with the position detection results detected by the second and third position detection means (11, 13) and (11, 14), and the first and second substrates W1 and W2 are respectively associated with the first and second substrates W1 and W2. When each pattern is exposed,
During each previous exposure process for the second and first substrates W2 and W1, the alignment position detecting means (AA1a,
AA1b), (AA2a, AA2b)
And each alignment mark WM of second substrate W1, W2
a and WMb to control the position of the substrate stage ST based on the position information of each of the first substrate W1 and the second substrate W2.
And a stage movement control means 30 (FIG. 4) for alternately moving the exposure position and the mark observation position.

First and second substrates W1 and W2 are held side by side on substrate stage ST, and when one substrate W1 is exposed to a mask pattern, alignment information of the other substrate W2 is detected in parallel. . Using the alignment information of the other substrate W2 obtained in this manner, the positioning of the substrate W2 when exposing the mask pattern to the other substrate W2 is performed. Further, position detecting means 11 and 12 of the substrate stage ST used for positioning at the exposure position, and position detecting means 1 of the substrate stage ST used for detecting alignment information at the alignment position.
Each of the exposure positions 1 and 13 (or 11 and 14) is positioned such that the Abbe error is substantially zero with respect to the exposure position and the alignment position. Also, since the detection results of both the position detecting means are associated in advance, there is no possibility that the positioning accuracy is reduced.

[0010] In the means and means for solving the above problems which explain the constitution of the present invention, the drawings of the embodiments are used to make the present invention easy to understand. However, the present invention is not limited to this.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of an exposure apparatus according to the present invention will be described with reference to FIGS. 1 is a perspective view showing a schematic configuration of an exposure apparatus, FIG. 2 is a plan view thereof, and FIG. 3 is a view showing an arrangement of each optical system and an arrangement of an alignment mark on a wafer. The direction and the Y direction are defined. The exposure apparatus is provided with an intersection O between the X axis and the Y1 axis.
A projection optical system PL whose optical axis is the axis AX1 passing through
With respect to the intersection O2 between the X axis and the Y2 axis, X
An alignment optical system AA1a having an axis AX2a passing through the axis as an optical axis, and an alignment optical system AA2a having an axis AX3a passing through the X axis in a predetermined positional relationship with respect to an intersection O3 between the X axis and the Y3 axis. And Note that X, Y1
Each of the .about.Y3 axes is defined by the respective measurement beams LBx, LBy1, LBy2, LBy3 of the laser interferometers 11 to 14.

Here, the alignment optical systems AA1a and AA1a
A2a is for observing the alignment mark WMa (FIG. 3) on the wafer W and detecting the position in the Y direction, and observing the alignment mark WMb paired with the alignment mark WMa and observing the X direction. Optical systems AA1b and AA for detecting the position of
2b. In the present embodiment, the alignment optical systems AA1a and AA1b are called first alignment optical systems, and the alignment optical systems AA2a and AA2b are called second alignment optical systems.

ST is a substrate stage that holds wafers W1 and W2, and is driven in the X direction by an X direction drive motor M1 and in the Y direction by a Y direction drive motor M2 within the image plane of the optical system PL. The wafers W1 and W2 are held on a θ stage (not shown), and are rotatable by θ.
R is a reticle held on a reticle stage (not shown), and a pattern formed on the reticle is exposed to a wafer W1 or W2 via an optical system PL by illumination light from an illumination system (not shown). Is done.

As shown in FIG. 3A, the distance ΔX2 between the Y1 axis and the Y3 axis (that is, the distance between the optical axis AX1 of the projection optical system PL and the optical axis AX3b of the alignment optical system AA2b in the X direction) is ΔX2. As shown in FIG. 3 (c), the center of an arbitrary exposure area SA1a of the wafer W1 is aligned with the optical axis A of the projection optical system PL.
When it is matched with X1 (intersection O1), the centers of alignment marks WMa and WMb formed on the street line accompanying exposure area SA2a formed at substantially the same position as the previous exposure area SA1a on wafer W2. Are the optical axes AX3a and AX3 of the alignment optical systems AA2a and AA2b.
b (in other words, the center of the exposure area SA2a substantially coincides with the intersection O3). here,
Substantially matching means that the alignment marks WMa and WMb on the wafer W2 are aligned by the alignment optical systems AA2a and AA2b.
Optical system AA2A, A within the range where
A2b is located.

Similarly, the distance between the Y1 axis and the Y2 axis is such that when the center of an arbitrary exposure area of the wafer W2 is coincident with the optical axis AX1 of the projection optical system PL, the distance of the previous wafer W2 The centers of the alignment marks WMa and WMb formed on the street line accompanying the exposure area formed at substantially the same position as the exposure area are aligned with the alignment optical system AA.
1a and AA1b substantially coincide with the optical axes AX2a and AX2b (in other words, the center of the exposure area on the wafer W1 and the intersection O2
Are substantially matched).

As shown in FIG. 3, alignment marks W provided on street lines of wafers W1 and W2 are provided.
The displacement of Ma and WMb is caused by the alignment optical system AA1.
A, AA1b and AA2a, AA2b are detected as positional deviations from index marks provided at positions conjugate to the alignment marks WMa, WMb.
Therefore, the index marks are indicated by the optical axes AX2a, AX2b, AX
3a and AX3b. Then, the alignment mark W of the wafer W1 is placed on the one-dimensional or two-dimensional image sensor built in the alignment light emitting and receiving unit DT1.
Ma, WMb and the image of the index mark corresponding to each are formed. Similarly, the wafer W2 is placed on a one-dimensional or two-dimensional image sensor built in the alignment light emitting / receiving unit DT2.
The alignment marks WMa, WMb and the corresponding index mark images are formed. Output signals from these image sensors are output to signal processing circuits SC1 and SC1 shown in FIG.
SC2, the shift amounts in the X and Y directions for each exposure area of wafers W1 and W2 are detected.

As shown in FIG. 2, the substrate stage ST
At the upper end, two sets of reflecting mirrors (fixed mirrors) MRx and MRy for reflecting the laser beam from the laser interferometer are provided substantially orthogonal to each other. The position of the substrate stage ST in the Y direction is detected by a known laser interferometer 11 and
-14 detect at three points. In these laser interferometers 11 to 14, the central axes (measuring axes) of the laser beams LBx and LBy1 emitted from the laser interferometers 11 and 12 are orthogonal to each other in the same plane, and the optical axis of the projection optical system PL. AX1 passes through the intersection O1, and the laser interferometer 1
Laser beams LBx, L emitted from the light emitting devices 1 and 13, respectively.
The center axis (measuring axis) of By2 is orthogonal in the same plane, and the first alignment optical system AA1 is located at the intersection O2.
a, AA1b are in a predetermined positional relationship, and their optical axes AX2a,
AX2b passes through the X axis and the Y2 axis, and the laser beams LBx, LBx emitted from the laser interferometers 11 and 14, respectively.
The center axis (measurement axis) of LBy3 is orthogonal to the same plane and the second alignment optical system AA with respect to the intersection O3.
2a and AA2b are in a predetermined positional relationship and their optical axes AX3
a and AX3b are configured to pass through the X axis and the Y3 axis, respectively. The plane including these four measurement axes is arranged so as to substantially coincide with the image plane of the projection optical system PL. That is, the laser interferometers 11 and 12 are at the exposure position (optical axis AX1), the laser interferometers 11 and 13 are at the mark observation positions of the alignment optical systems AA1b and AA1a, and the laser interferometers 11 and 14 are at the mark observation positions. Each mark observation position of the alignment optical systems AA2b and AA2a is configured such that the Abbe error is substantially zero or negligible in terms of alignment accuracy.
For example, as shown in FIG. 3 (c), the second alignment optical systems AA2a and AA2b are provided with the measurement directions of the marks WMa and WMb and the measurement beams LBx and LBy3 of the interferometers 11 and 14.
(That is, the X axis and the Y3 axis) are substantially orthogonal to each other, and are disposed away from the Y3 axis and the X axis by the distances ΔEx and ΔEy. Therefore, the distances ΔEx and ΔEy and the rotation of the substrate stage ST Optical system AA2a, AA2b by a value determined by the amount (yawing amount).
Although a measurement error may occur, the value is minute and negligible.

A reference mark SM is provided on the substrate stage ST. This reference mark SM has an offset value ΔX1 that is a distance between the Y1 axis and the Y2 axis, an offset value ΔX2 that is a distance between the Y1 axis and the Y3 axis, or the substrate stage ST, that is, each of the three sets of interferometers 12 to 14. It is used to detect in advance an offset amount due to a mounting error (tilt) of the fixed mirror MRy used when associating output values. First, the reference mark SM is aligned with the mark RMb (FIG. 3A) provided on the reticle R by, for example, an observation optical system arranged above the reticle.
The output signal of the laser interferometer 11 is read in this state (the state where the alignment error is almost zero). Next, the reference mark SM is detected by each of the alignment optical systems AA1b and AA2b, and the laser interference is performed in a state where the positional deviation of the reference mark SM from the mark detection position of each alignment optical system (that is, the above-described index mark) is almost zero. The output signal of the total 11 is read.

The difference between the two output signals obtained from the laser interferometer 11 is represented by the distance ΔX1 between the Y1 axis and the Y2 axis.
It is. Similarly, the distance ΔX2 between the Y1 axis and the Y3 axis is detected. Now, assuming that the intersection O1 with the Y1 axis is the origin of the X axis and the direction of the intersection O2 is the positive direction, the alignment optical system AA1b at the exposure position (the optical axis position of the projection optical system PL).
The alignment information in the X-axis direction detected by the following is used as a value obtained by subtracting the offset value ΔX1, and the alignment information in the X-axis direction detected by the alignment optical system AA2b is used as a value obtained by adding the offset value ΔX2. Further, these offset values correspond to wafers W1 and W
2 is used to move between the alignment position and the exposure position.

In each of the three sets of interferometers 12 to 14, the substrate stage ST is in a predetermined neutral state (position), for example, when the substrate stage ST moves in both positive and negative directions with respect to the X-axis direction. , The counters (not shown) for counting up-down pulses from the interferometer are preset (for example, reset to zero), or the respective counts are stored. Thus, the output values (count values) of the three sets of interferometers 12 to 14 are associated with each other, and at the exposure position (optical axis position of the projection optical system PL), the substrate stage by the interferometer 12 in the Y-axis direction is used. Under the monitor of ST, the alignment information in the Y-axis direction detected by each of the alignment optical systems AA1a and AA2a is used as it is (or, when each count value is stored at the time of association, an offset value is given by the difference). Can be used).

As described above, three sets of interferometers 12 to
When performing the association of 14, the counter cannot be accurately associated even if the counter is preset at the previous neutral position due to an attachment error (tilt) of the fixed mirror MRy with respect to the substrate stage ST. Therefore, as described below, it is desirable to previously use the reference mark SM to determine the error amount at the time of associating the interferometers 12 to 14 due to the inclination as the offset amount.

Next, detection of the offset amount will be described. Just like the measurement operation of the offset values ΔX1 and ΔX2, the reference mark SM is obtained by an observation optical system (not shown).
Is a mark RMa provided on the reticle R (FIG. 3C)
Then, the output signal of the laser interferometer 12 is read in that state (the state in which the amount of displacement is substantially zero). Next, the reference mark SM is aligned with the alignment optical systems AA1a and AA1a.
A2a detects the output signals of the laser interferometers 13 and 14 in a state where the amount of displacement of the reference mark SM with respect to the mark detection position of each alignment optical system is substantially zero. The difference between the positions in the Y-axis direction detected by the laser interferometers 12 and 13 as described above is stored as ΔDY1.
Similarly, the difference between the positions in the Y-axis direction detected by the laser interferometers 12 and 14 is stored as ΔDY2. Then, the amount of misalignment of the wafer W1 and the wafer W2 in the Y-axis direction (coordinate position of each exposure area) obtained in the following alignment information detecting step is added to the interferometer 12 at the exposure position with these ΔDY1 and ΔDY2 or Subtract and use.

When the interferometers 12 to 14 are associated with each other, the reference mark SM is used, and the positional deviation between the reticle mark RMa, each of the alignment optical systems AA1a and AA2a, and the reference mark SM becomes almost zero. In this state, the count value of each counter may be preset or stored. In this case, there is an advantage that an error due to yawing can be canceled even if the substrate stage ST is yawing (rotating) at the time of performing the preset or the like.

FIG. 4 is a block diagram of a control system according to the present embodiment. The control circuit 30 includes a CPU, a RAM, and a ROM.
A control circuit composed of other peripheral circuits, etc.
The control circuit 30 includes the four laser interferometers 11 to 11 described above.
In addition to the input of the output signal 14, the alignment information on the wafer W1 is input from the first alignment-system signal processing circuit SC1 and the alignment information on the wafer W2 is input from the second alignment-system signal processing circuit SC2.

The signal processing circuit SC1 generates a mark WMa, a mark on the wafer for the index mark based on the alignment information from the first alignment optical systems AA1a and AA1b.
In addition to detecting the displacement of the WMb in the Y and X directions,
The position information from the interferometers 11 and 13 is also input, and the coordinate positions of the wafer marks WMa and WMb (that is, the exposure regions) in the Y and X directions are obtained. On the other hand, the signal processing circuit SC2
Information from the alignment optical systems AA2a and AA2b and the interferometers 11 and 14 is input, and the coordinate positions of the wafer marks WMa and WMb in the Y and X directions are obtained in the same manner as described above.

The control circuit 30 controls the position of the substrate stage ST by driving the X-axis motor M1 and the Y-axis motor M2 while monitoring the position information from the interferometers 11 to 14 via the stage controller 31. Particularly, in the present embodiment, the signal processing circuits SC1 and SC
2 (ie, the array coordinate values of all the exposure areas on the wafers W1 and W2) and the offset values ΔX1 and ΔX1
X2 (ΔDY1, ΔDY2 if necessary), and using the position information from interferometers 11 and 12, substrate stage ST
, Each exposure area on the wafer is accurately positioned with respect to the exposure position.

Next, the operation of this embodiment will be described with reference to the processing procedure flow shown in FIG. First, in step S1, the substrate stage ST is moved to a predetermined wafer transfer position. Next, the wafer W1 and the wafer W2 are loaded (Step S2). After the loading is completed, fine alignment is performed on the wafer W1 (Step S3). In the fine alignment, the alignment marks WMa and WMb provided for each of the plurality of exposure regions on the wafer W1 are observed with the alignment optical systems AA1a and AA1b, and the X and Y directions with respect to the reference marks are observed. This is performed by detecting a direction shift. As a result, in the signal processing circuit SC1, the coordinate system XY
The coordinate values of all the exposure areas on the wafer W1 in 2 are calculated.

After the fine alignment with respect to the wafer W1, the X-axis motor M is moved so that the center of the first exposure area of the wafer W1 coincides with the optical axis AX1 of the projection optical system PL.
1 and the Y-axis motor M2 are driven (step S4). At this time, the position control of the substrate stage ST is performed using the laser interferometers 11 and 12, but the position control is performed in consideration of the fine alignment result and the offset value ΔX1 with respect to the first exposure region of the wafer W1 performed earlier. . In other words, the coordinate value of the entire exposure area on the wafer W1 is converted from the coordinate value XY2 to the coordinate system XY1 using the offset value ΔX1, and the position of the substrate stage ST is controlled according to the coordinate value on the coordinate system XY1. .

That is, when controlling the position in the X direction,
The offset value ΔX1 between the Y1 axis and the Y2 axis is subtracted from the X position data of the alignment mark WMb of the top exposure area on the wafer W1 obtained by the interferometer 11 during exposure of the top exposure area of the wafer W2, and the substrate stage ST Position control is performed so that the X position becomes the subtraction value. In controlling the position in the Y direction, the stage substrate S detected by the interferometer 12
The position control is performed so that the Y position of T becomes the Y position data of the alignment mark WMa of the top exposure area on the wafer W1 obtained by the interferometer 13 during the exposure of the top area of the wafer W2.

In this manner, the positioning with respect to the head region of the wafer W1 is performed, and the pattern on the reticle R is exposed to the exposure region of the wafer W1 by irradiating the exposure light. Thereafter, the wafer W1 is moved in the X and Y directions in accordance with the alignment information for each exposure area, and the pattern is exposed while sequentially aligning the center of the exposure area with the optical axis AX1 of the projection optical system PL (step S5). .

When the substrate stage ST is sequentially moved in the X and Y directions during the exposure of the wafer W1, the wafer W2 also moves at the same pitch, and the alignment marks WMa and WMb of each exposure area on the wafer W2 are changed. It enters a region that can be sequentially observed by the alignment optical systems AA2a and AA2b. Therefore, at this time, the amount of displacement between each alignment mark and the reference mark in the X and Y directions is detected. Therefore, detection of alignment information for wafer W2 (that is, coordinate values of all the exposure areas on wafer W2 in coordinate system XY3) is performed in parallel with exposure of wafer W1 (step S5).

When the exposure is completed for all the exposure areas on the wafer W1, the alignment information of all the exposure areas on the wafer W2 has been detected. Then, using the alignment information and the offset value ΔX2 obtained in this way, coordinate conversion (XY2 →
XY1) to move the substrate stage ST so that the center of the top exposure area of the wafer W2 coincides with the optical axis AX1 of the projection optical system PL (Step S6). Next, the wafer W1 that has been exposed is unloaded and a new wafer W1 is loaded (step S7).

Next, the position of the substrate stage ST is controlled so that the center of the top exposure area of the wafer W2 coincides with the optical axis AX1 of the projection optical system PL, and after positioning, the pattern of the reticle R is transferred to the top exposure area of the wafer W2. Exposure. further,
As described above, exposure is sequentially performed using the alignment information obtained at the time of exposing the wafer W1 while aligning the center of each exposure area of the wafer W2 with the optical axis AX1 of the projection optical system PL. During the exposure of the wafer W2, the alignment marks WMa and WMb provided on the street lines of the respective exposure areas of the third wafer W1 move to the positions observed by the alignment optical systems AA1a and AA1b. Alignment information for each exposure area of W1 can be detected (step S8).

When all the exposure for the wafer W2 is completed, all the alignment information for the wafer W1 is obtained. Therefore, the wafer W2 that has been exposed is unloaded, and a fourth wafer W2 is newly loaded (step S9). Then, the center of the top exposure area of the wafer W1 is made to coincide with the optical axis AX1 of the projection optical system PL, and thereafter, the same procedure is repeated to perform exposure work on a plurality of wafers.

According to the above procedure, since the exposure and the alignment are performed in parallel, the throughput is improved as compared with the conventional method in which the exposure step and the alignment step are performed separately. Further, since the laser interferometers 11 to 14 are arranged in a positional relationship as described above, even if the exposure position and the alignment detection position are different, an Abbe error does not occur and accurate positioning can be performed.

In the above-described embodiment, the die-by-die method has been described.
Since alignment information can be measured for the entire exposure area of the other wafer in parallel with the exposure process for one wafer, the number of data points used for statistical processing can be increased (extremely using the data of the entire exposure area). Even if the performance is improved, the throughput does not decrease unlike the conventional case,
The method is also very effective. That is, even the mark detection error of the alignment optical system can be averaged to improve the alignment accuracy.

In the above description, the alignment optical systems for the wafers W1 and W2 are provided in the X and Y directions, respectively. However, depending on the shape of the alignment mark on the wafer, the alignment optical systems in the X and Y directions may be shared. Can also.

In the configuration of the above embodiment, the interferometers 11 and 12 serve as the first position detecting means, and the interferometers 11 and 13
Represents the second position detecting means, the interferometers 11 and 14 represent the third position detecting means, the light emitting / receiving sections DT1 and DT2 represent the alignment position detecting means, and the stage controller 31 and the control circuit 30 represent the stage movement controlling means. Configure each.

In the above embodiment, as shown in FIG. 3C, the first and second alignment optical systems (AA1a, AA1
A1b) and (AA2a, AA2b) for each of the interferometers (13,
11) and (14, 11) were not arranged. Therefore, only the alignment optical systems AA1a and AA2a have the interferometers 13 and 14 so that the Abbe error is almost zero.
, Ie, each measurement axis (Y) of the interferometers 13 and 14
Optical axis AX of each alignment optical system
2a and AX3a may be arranged so as to match.

The first alignment optical system AA1
If one set of alignment optical systems is further provided at positions a and AA1b at positions substantially symmetrical with respect to the intersection O2 with one of them, the rotation amount of each exposure region on the wafer (so-called chip rotation) can be obtained in advance. it can. Therefore, if the exposure is performed while rotating the reticle R for each exposure region based on the previously detected rotation amount for each exposure region, the chip rotation can be corrected.

Further, in the above embodiment, an exposure apparatus having a projection optical system has been described as an example. However, the present invention can be applied to a proximity type or contact type exposure apparatus to obtain the same effect. Obtainable.

For the exposure of the first wafer, it is not necessary to detect the coordinate values of all the exposure regions using the die-by-die method, and the EGA method may be employed.

In the above embodiment, only one set (11) of X-axis direction interferometers is arranged and shared at the exposure position and the two alignment positions. It may be provided.

Next, a second embodiment of the present invention will be described with reference to FIGS. 6 and 7, FIG.
Members having the same functions and functions as the members in FIG. 3 to FIG. 3 are denoted by the same reference numerals, and both are diagrams corresponding to FIG. The first embodiment is different from the first embodiment in that the Abbe error is zero for each of the first and second alignment optical systems (AA1a, AA1b) and (AA2a, AA2b). And the difference.

As shown in FIG. 6, the first alignment optical systems AA1a and AA1b are respectively arranged on the Y2 axis and the X axis, and as shown in FIG. 7, the second alignment optical systems AA2a and AA2b are respectively arranged. They are arranged on the Y3 axis and the X axis. That is, the wafer marks WMa to WMd
Are almost coincident with the Y3 axis, the X axis, the Y2 axis, and the X axis. As a result, the interferometer 1 is set so that the Abbe error becomes zero for all the alignment optical systems.
1, 13, 14 will be arranged. However, in the present embodiment, the first configuration is adopted by adopting the above configuration.
The same alignment mark WM in each exposure region between the alignment optical system and the second alignment optical system.
a, WMb cannot be detected. Therefore, in addition to the alignment marks WMa and WMb, two more sets of alignment marks WMc and WMd are formed in association with the exposure area, and the first alignment optical system AA1
a and AA1b detect alignment marks WMc and WMd, and the second alignment optical systems AA2a and AA2b are detected.
Then, it is necessary to detect the alignment marks WMa and WMb. Further, when the above configuration is employed, it is necessary to obtain not only the offset values ΔX1 and ΔX2 in the X direction but also the offset values ΔY1 and ΔY2 in the Y direction in advance. What is necessary is to perform using. By adopting such a configuration, even if the chip (exposure area) size on the wafer is enlarged, the advantage that the alignment accuracy does not decrease is obtained because the Abbe error is zero.

Next, a third embodiment will be described with reference to FIGS. 8 to 10, members having the same functions and functions as those in FIGS. 1 and 4 are denoted by the same reference numerals. The present embodiment is different from the first embodiment in that a focusing operation or a leveling operation is performed in addition to the alignment operation similar to the above embodiment. Also, here, for simplicity of description, only the first alignment optical system will be described.

As shown in FIG. 8, in the present embodiment, the first
Oblique incidence light type surface position detection system 6 for detecting the height position (position in the Z direction) of the wafer surface integrally with the alignment optical systems AA1a and AA1b (only AA1b is shown).
0 and 61 are provided. Surface position detection system 60, 61
Indicates a plurality of points in the exposure area SA (points indicated by black circles in FIG. 9)
Are detected in the Z-direction at each of the above.
No. 6,086,045. In this publication, a system for detecting a position in the Z direction at one point in the exposure area is disclosed. However, as the surface position detection systems 60 and 61, a combination of a plurality of these detection systems or a long slit is used. An image may be formed on the surface of the exposure area, and the slit image may be divided into a plurality of parts by a one-dimensional line sensor or the like and received. Further, the surface position detection systems 60 and 61 include a projection optical system P
It is assumed that the calibration has been performed in advance so that the best imaging plane of L becomes the zero point reference.

The wafer W is placed on the substrate stage ST.
1, W2 integrally (or independently) in Z direction (optical axis direction)
And a leveling stage 51, 52 capable of independently tilting each of the wafers W1, W2. The leveling stages 51 and 5
The configuration of No. 2 is disclosed in JP-A-62-274201. FIG. 10 is a block diagram of a control system according to the present embodiment. The control circuit 30 gives a predetermined drive command to the Z-axis motor 64 and the leveling motor 65 based on a detection signal from the surface position detection system 61 to adjust the alignment position. Performs an apparent focusing operation and a leveling operation. At this time, the drive amounts of the Z stage 50 and the leveling stage 51 for each exposure area are detected by position detection systems 62 and 63 such as potentiometers, and the control circuit 30 stores the detected values in the storage unit 66. (Details described later).

Next, the operation of the apparatus having the above configuration will be briefly described. The control circuit 30 performs an alignment operation on each exposure region of the wafer W1 in parallel with the exposure operation on the wafer W2 as in the first embodiment.
Further, a focusing operation and a leveling operation are executed for each exposure area on the wafer W1 by using the surface position detection systems 60 and 61. Then, the values detected by the position detection systems 62 and 63 at this time are stored in the storage unit 66 for each exposure area. As a result, when the wafer W1 is exposed, by controlling the Z stage 50 and the leveling stage 51 for each exposure area based on the information stored in the storage unit 66, the focusing and the leveling operation can be accurately performed. It is possible to do. Since the wafer may be shifted laterally in the XY plane with the leveling operation (tilt of the wafer), the alignment operation may be performed after the leveling operation.
Alternatively, when performing both operations at the same time, it is desirable to calculate the lateral shift from the amount of tilt of the wafer by calculation, and to give this value as an offset to the alignment result. Thus, it is possible to prevent the alignment accuracy from being lowered due to the lateral displacement of the wafer caused by the leveling operation.

Here, in the above embodiment, the drive amount of the Z stage 50 and the leveling stage 51 detected together with the coordinate position of the exposure area at the alignment position of the first and second alignment optical systems (the position detection systems 62 and 63). Output value)
Is stored, but it is not necessary to store the driving amount of the Z stage 50 for the focusing operation.
In such a case, for example, in the projection optical system PL, a focus detection system of the oblique incident light system (Japanese Patent Laid-Open No. 60-1) is also integrally formed.
No. 68112) and calibration is performed in advance so that the best focus position (best focus position) of the projection optical system PL becomes the zero point reference. This focus detection system is, for example, a projection optical system PL.
The position in the Z direction may be detected at only one measurement point set near the optical axis AX1. In the device having such a configuration, first, at the alignment position, the focusing operation and the leveling operation are performed from the detection results of the surface position detection systems 60 and 61 (the positions in the Z direction at each measurement point), and then the surface position detection is performed. The output values of the systems 60 and 61, for example, only the shift amount of the surface of the exposure area at the measurement point near the center of the exposure area are stored. When exposure is performed on the exposure area, the Z stage 50 is positioned so that the output value of the focus detection system has an offset by the previously stored shift amount, so that the surface of the exposure area can be accurately determined. Can be set to the best focus position. If the projection optical system PL is provided with the surface position detection systems 60 and 61 and the amount of displacement at each of the plurality of measurement points is stored in the alignment position in the same manner as described above, the leveling stage 51 can be used even in the leveling operation. It is not necessary to store the driving amount, but only the deviation amount at each measurement point.

[0051]

As described in detail above, according to the present invention, when exposing a mask pattern on one substrate, alignment information detection on the other substrate is performed in parallel, and thus the present invention is obtained. The alignment information of the other substrate is used to position the substrate when exposing the mask pattern to the other substrate. Further, a position detection means of the substrate stage used for positioning at the exposure position, and a mark Since the position detection means of the substrate stage used for detecting the alignment information at the observation position is positioned so that the Abbe error is substantially zero with respect to the exposure position and the mark observation position, the throughput is improved, and the exposure position and the exposure position are improved. Even if separate position detecting means are used for the mark observation position, there is no possibility that the positioning accuracy is reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a schematic configuration of an exposure apparatus according to the present invention.

FIG. 2 is a plan view of the exposure apparatus of FIG.

FIG. 3 is a diagram for explaining an arrangement of a projection optical system and an alignment optical system and an arrangement of an alignment mark on a wafer.

FIG. 4 is a block diagram showing a control system of the exposure apparatus of FIG.

FIG. 5 is a flowchart illustrating an exposure process and an alignment process of the exposure apparatus of FIG. 1;

FIG. 6 is a diagram corresponding to FIG. 3 (c) and illustrating a second embodiment.

FIG. 7 is a diagram corresponding to FIG. 3C and illustrating a second embodiment.

FIG. 8 is a front view of a stage according to a third embodiment.

FIG. 9 is a diagram illustrating an exposure area.

FIG. 10 is a block diagram illustrating a control system according to a third embodiment;

FIG. 11 is a perspective view of a conventional exposure apparatus.

[Explanation of symbols]

W1 First wafer (first substrate) W2 Second wafer (second substrate) PL Projection optical system R Reticle ST Substrate stage AA1a, AA1b First alignment optical system AA2a, AA2b Second alignment optical system M1 X-axis Motor M2 Y-axis motor 11 Interferometer 12-14 Interferometer 30 Control circuit 31 Stage controller

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[Procedure amendment]

[Submission Date] September 6, 1999 (September 9, 1999)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Name of invention

[Correction method] Change

[Correction contents]

An exposure apparatus, a device manufactured by the exposure apparatus, an exposure method, and a device manufacturing method using the exposure method

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction contents]

[0008]

According to the present invention, there is provided an exposure apparatus for exposing a predetermined pattern on a substrate positioned at a predetermined exposure position (on an optical axis AX1 on ST in FIG. 1). A first mounting means (51, ST1 in FIG. 1) for mounting the first substrate (W1) and positioning the first substrate at the exposure position.
Upper portion O2) and a second substrate (W2) different from the first substrate and a second mounting means (52, ST on FIG. 1) for positioning the second substrate at the exposure position. O1 part)
And detecting the position of the first mounting means when the first substrate is positioned at the exposure position, and detecting the position of the second mounting means when the second substrate is positioned at the exposure position. (11, 12) for detecting the According to the fifth aspect of the present invention, the first mounting means (51, O2 on ST in FIG. 1) for mounting the first substrate (W1).
And second mounting means (52, O1 on ST in FIG. 1) for mounting a second substrate (W2) different from the first substrate;
Observation position (on the optical axis AX2 or AX3) for observing the substrate mounted on one of the mounting means.
And a position different from the observation position and an exposure position (on the optical axis AX1) at which a predetermined pattern is exposed on the substrate on the one mounting means, the position of the one mounting means is changed. The detecting device (11 to 14) for continuously detecting is configured in the exposure apparatus. Further, according to the tenth aspect, an exposure apparatus that exposes a predetermined pattern onto a substrate positioned at a predetermined exposure position (on the optical axis AX1) is provided to the first substrate (W).
1) First mounting means (51, O on ST in FIG. 1) for mounting
2) and a reference member (SM) provided in the vicinity of the first mounting means as a reference.
First observation means for observing a substrate (AA1a, AA1b)
And second mounting means (52, O1 on ST in FIG. 1) for mounting a second substrate (W2) different from the first substrate;
Second observation means (AA2a, AA2b) for observing the second substrate on the second placement means with reference to a reference member (SM) provided near the second placement means; When positioning the substrate at the exposure position, the position of the first mounting means is controlled based on the observation result by the first observation means,
When positioning the second substrate at the exposure position, the second substrate
Control means (30, 31) for controlling the position of the second mounting means based on the observation result by the observation means. The invention according to claim 23 is an exposure method for exposing a predetermined pattern on a substrate positioned at a predetermined exposure position (on the optical axis AX1), wherein the first mounting means (51, FIG.
When the first substrate (W1) is positioned at the exposure position by the O2 portion on the ST, the detection means (11,
12), the position of the first mounting means is detected, and a second substrate (W2) different from the first substrate is moved to the second mounting means (5).
2, the position of the second mounting means is detected by the detecting means when the exposure means is positioned at the exposure position by O1 on ST in FIG. 1). In the invention according to claim 25, the first substrate (W1) is placed on the first mounting means (5).
1, a second substrate (W2) different from the first substrate is placed on the second placing means (52,
An observation position (on the optical axis AX2 or the optical axis AX3) placed on the ST1 in FIG. 1 to observe the substrate placed on one of the placing means. Above) and an exposure position (optical axis AX1) at a position different from the observation position and where a predetermined pattern is exposed on the substrate on the one mounting means.
Between (1) and (2), the position of the one mounting means is continuously detected. The invention according to claim 28 is an exposure method for exposing a predetermined pattern on a substrate positioned at a predetermined exposure position (on the optical axis AX1),
The first substrate (W1) is placed on the first placement means (51, O2 portion on ST in FIG. 1), and the reference member (SM) provided near the first placement means is referenced. Observing the first substrate on the first mounting means, and a second substrate different from the first substrate
The substrate (W2) is mounted on the second mounting means (52, O1 part on ST in FIG. 1), and the reference member (SM) provided near the second mounting means is used as a reference. Observing the second substrate on the second mounting means, and positioning the first substrate to the exposure position, the position of the first mounting means based on the observation result of the first substrate. When the second substrate is positioned at the exposure position, the position of the second mounting means is controlled based on the observation result of the second substrate.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction contents]

According to the invention described in claim 1 or claim 23, no matter which mounting means (51 or 52) is present at the exposure position (on the optical axis AX1), the common detecting means (11). , 12) also serves to detect the position of the mounting means (51 or 52).
1 or 52), the configuration and operation of the exposure apparatus can be simplified. Therefore, a two-substrate processing method for a substrate can be realized while reducing the size and cost of the exposure apparatus. Claim 5 or Claim 2
According to the invention described in Item 5, the substrate observation position (on the optical axis AX2 or on the optical axis AX3) and the exposure position (on the optical axis AX1) of the mounting means (51 or 52) on which the substrate (W1 or W2) is mounted.
Since the movement position (displacement) between the upper and lower positions is constantly monitored, accurate position measurement of the mounting means (identification of the current position) becomes possible. Can be positioned. According to the invention described in claim 10 or claim 28, when positioning each substrate (W1 or W2) at the exposure position, any of the observation results of each substrate with reference to the reference member (SM) is used. Since the position of the corresponding mounting means is controlled based on the
There is an advantage that the position control in any case can be performed accurately. As described above, according to the present invention, while using a processing method of a plurality of substrates to improve throughput, more accurate position control of the exposure position of each substrate, miniaturization of the apparatus, and cost reduction Can be achieved.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0051

[Correction method] Change

[Correction contents]

[0051]

As described above in detail, according to the present invention, it is possible to use a processing method of a plurality of substrates for improving the throughput and to control the exposure position of each substrate more accurately. Thus, downsizing of the apparatus and cost reduction can be achieved. According to the invention as set forth in claim 1 or claim 23, regardless of which mounting means (51 or 52) exists at the exposure position (on the optical axis AX1), the common detecting means (11, 12). And the position detection of the mounting means (51 or 52) is also used, so that the configuration and operation of the exposure apparatus having two substrate mounting means (51 or 52) can be simplified. Therefore, a two-substrate processing method for a substrate can be realized while reducing the size and cost of the exposure apparatus. According to the invention described in claim 5 or claim 25, the substrate observation position (on the optical axis AX2 or on the optical axis AX3) of the mounting means (51 or 52) on which the substrate (W1 or W2) is mounted. Since the movement position (displacement) between the position and the exposure position (on the optical axis AX1) is constantly monitored, accurate position measurement (identification of the current position) of the mounting means becomes possible. Thus, the substrate can be accurately positioned at the exposure position. According to the invention described in claim 10 or claim 28, when positioning each substrate (W1 or W2) at the exposure position, any of the observation results of each substrate with reference to the reference member (SM) is used. Since the position control of the corresponding mounting means is performed based on this, there is an advantage that the position control in any case can be accurately performed.

Claims (1)

[Claims] 1. An exposure apparatus for exposing a pattern formed on a mask onto a photosensitive substrate, comprising: a substrate stage that holds a first substrate and a second substrate and moves two-dimensionally; The substrate stage is arranged such that the Abbe error is almost zero.
First position detecting means for detecting a dimensional position; and mark observing means for observing an alignment mark formed on the first substrate, wherein a center point of the second substrate coincides with the exposure position. When the first position is set, the first alignment mark is arranged in a predetermined positional relationship with respect to the exposure position so that the alignment mark on the first substrate substantially matches the mark observation position.
Mark observing means, and second position detecting means arranged to detect a two-dimensional position of the substrate stage, wherein the Abbe error is arranged to be substantially zero with respect to a mark observing position of the first mark observing means. And mark observing means for observing an alignment mark formed on the second substrate, wherein when the center point of the first substrate is coincident with the exposure position, the alignment mark of the second substrate is a mark. A second position that is arranged in a predetermined positional relationship with respect to the exposure position so as to substantially coincide with the observation position.
A mark observing means, a third position detecting means arranged so that an Abbe error is substantially zero with respect to the second mark observing means, and detecting a two-dimensional position of the substrate stage; Alignment position detecting means for detecting the positions of the respective alignment marks when the first and second alignment marks are observed by the first and second mark observing means, respectively, and a detection result of the first position detecting means. When the patterns are respectively exposed on the first and second substrates, the patterns are respectively associated with the position detection results detected by the second and third position detecting means, respectively.
The position of the substrate stage is controlled based on each position information of each alignment mark of the first and second substrates detected by the alignment position detecting means during each exposure step on the substrate, and the first substrate and the second substrate are controlled. An exposure apparatus comprising: stage movement control means for alternately moving a substrate to an exposure position and a mark observation position.