JPH0982607A - Exposure method - Google Patents

Abstract

(57) [Summary] [Objective] To provide an exposure method capable of superimposing a reticle pattern on a shot area with high accuracy without being affected by the lens distortion of an alignment target layer exposure machine. [Structure] Since the distortion data of the projection lens of each exposure machine is already known for each exposure machine, when the alignment target layer exposure machine is known, the multipoint EGA calculation is performed using the known data of the exposure machine. The projection magnification and / or shot rotation obtained in step S1 is corrected, and the exposure apparatus is adjusted by the corrected amount (steps 105, 10).
6). When the alignment target layer exposure machine is unknown, the alignment mark exposure machine is specified from the distribution state of the non-linear error calculated from the alignment mark measurement value in the shot. The reticle pattern is exposed with high precision by superimposing it on the shot area under the correct projection magnification and shot rotation thus obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure method for projecting and exposing a mask or reticle pattern on a photosensitive substrate in a lithography process which is one process of manufacturing a semiconductor integrated circuit, a liquid crystal display device and the like.

[0002]

2. Description of the Related Art A reduction projection type exposure apparatus (stepper) is used for manufacturing a semiconductor integrated circuit or the like, and a mask or reticle (hereinafter referred to as "reticle") is applied to a chip pattern (shot area) already formed on a semiconductor wafer. The new circuit pattern of 1) is superimposed and exposed, and at that time, it is important to perform alignment with respect to the shot area and adjustment of the exposure device with high accuracy.

A large number of shot areas are regularly arranged on the wafer based on preset arrangement coordinates, and a chip pattern including alignment marks for alignment is formed in each shot area. As a method of aligning a reticle pattern with a shot area of a wafer, for example, an enhanced global alignment method (hereinafter, referred to as "multipoint", which takes into account chip magnification, rotation, etc., as described in JP-A-6-275496. EGA
Method)) is known.

The alignment of the multipoint EGA system will be described. This method is based on the factors listed in (1) to (7) below as the error between the measured position and the designed position of the alignment marks provided at multiple points in the shot area. Is used to calculate the array coordinates of shots to be aligned, the chip magnification, rotation, and the like. (1) Residual rotation error Θ of wafer, (2) Orthogonality error W of stage coordinate system (or shot arrangement), (3) Linear expansion and contraction Rx, Ry of wafer, (4) Offset of wafer center position (translation) O _X , O _Y , (5) residual rotation error θ of the chip pattern on each shot area of the wafer, (6) orthogonality error w of the coordinate system (chip pattern) on the wafer, (7) orthogonality of the chip pattern Linear expansion / contraction rx, ry in two directions. here,
The error parameters Θ, W, Rx, Ry, Ox, Oy are defined with respect to the stage coordinate system X, Y, and the error parameters θ, w, rx, ry with respect to the chip pattern with respect to the coordinate system x, y of the shot area. Is defined.

The designed array coordinate values on the coordinate system (α, β) on the wafer of the reference points (for example, the shot centers) of a plurality of shot areas selected on the wafer were measured as C _n . The design coordinate value (relative coordinate value) in the coordinate system (x, y) on each shot area of the alignment mark is S _Nn ,
When the calculated coordinate value of the alignment mark on the stage coordinate system (X, Y) is F _Nn , F _Nn is expressed as in the following ( _Equation 1).

[0006]

[Equation 1]

However, each vector and conversion matrix in the above equation are defined as in the following (Equation 2). Here, the residual rotation error Θ of the wafer, the orthogonality error W, the residual rotation error θ of the chip pattern, and the orthogonality error w are assumed to be minute amounts, and a linear approximation is performed, and Rx = 1 + Γx, Ry = 1 + Γy, It is assumed that rx = 1 + γx and ry = 1 + γy, and that Γx, Γy, γx, and γy are minute amounts, and approximation is performed.

[0008]

[Equation 2]

Then, ten error parameters (Θ, W, Γx, Γy, O) that satisfy (Equation 1) by the method of least squares are used.
_X , O _Y , θ, w, γx, γy) is obtained. Specifically, the difference (E _NXn , E _NYn ) between the actually measured coordinate value (FM _NXn , FM _NYn ) and the calculated coordinate value (F _NXn , F _NYn ) is considered as an alignment error. Therefore, E _NXn = FMF _NXn −
F _NXn , E _NYn = FM _NYn- F _NYn . And 5
Alignment error more than a set (E _NXn , E _NYn ), ie, 10
10 or more alignment errors are sequentially partial differentiated with these 10 error parameters, an equation that minimizes the value is created, and 10 simultaneous equations are solved by the least squares method. The error parameter of can be obtained.

Thereafter, by appropriately rotating the reticle or rotating the wafer so as to correct the rotation error θ of the chip rotation in the conversion matrix B, the chip relative to the stage coordinate system (X, Y). Correct the pattern rotation. Although the orthogonality error w of the chip cannot be corrected in a strict sense, the error can be suppressed small by appropriately rotating the reticle. Therefore, it is possible to optimize the rotation amount of the reticle or wafer so that the sum of the absolute values of the residual rotation error Θ of the wafer, the residual rotation error θ of the chip pattern, and the orthogonality error w is minimized. . Next, the projection magnification of the projection optical system is adjusted so as to correct the chip scaling errors γx and γy in the conversion matrix B. Then, using the conversion matrices A and O, the design array coordinate values (C _Xn , C _Yn ) of the reference points of each shot area on the wafer are substituted into the following (Equation 3) to obtain the reference. Calculated array coordinate values (G _Xn , G _Yn ) on the stage coordinate system (X, Y) of the points.

[0011]

(Equation 3)

Then, the array coordinates (G
_Xn , G _Yn ) and the baseline amount obtained in advance, the reference point of each shot area on the wafer is sequentially aligned with a predetermined position in the exposure field of the projection optical system,
The pattern image of the reticle is projected and exposed on the shot area. Then, after exposure of all shot areas on the wafer is completed, processing such as development of the wafer is performed.

According to the alignment of the multipoint EGA method, as shown in (Equation 1), the transformation matrices A and O
In addition to this, since the conversion matrix B including the parameters of chip rotation, chip orthogonality error, and chip scaling is also taken into consideration, the influence of expansion and contraction or rotation of the chip pattern itself transferred to each shot area is reduced. Therefore, the chip pattern of each shot area on the wafer and the projected image of the reticle pattern can be superimposed with high accuracy.

[0014]

In the multi-point EGA type alignment, in order to obtain intra-shot error, that is, chip rotation, chip orthogonality error, and chip scaling parameters, an alignment in which a plurality of points are arranged in the shot is performed. Measure the mark. But,
The coordinate value of the measured alignment mark includes an error due to the lens distortion of the alignment target layer exposure machine. Therefore, using the measured value as it is, the rotation error θ of the chip rotation is
To rotate the reticle or wafer to correct
If the projection magnification of the projection optical system is adjusted so as to correct the chip scaling errors γx and γy, a shot magnification error and a shot rotation error will occur.

It is an object of the present invention to provide an exposure method capable of superimposing a reticle pattern on a shot area with high accuracy without being affected by the lens distortion of an alignment target layer exposure machine.

[0016]

[Means for Solving the Problems] Each exposure apparatus (exposure number machine)
The distortion data itself of the projection lens is previously measured for each exposure machine and is known. Therefore, when the exposure machine that forms the alignment target layer is known, at least one of the projection magnification and the shot rotation obtained from the measured alignment target position is used by using the known lens distortion data of the exposure machine. Can be corrected. The reticle pattern is precisely overlapped and exposed in the shot area under the thus obtained correct projection magnification and shot rotation.

When the alignment target layer exposure machine is unknown, the alignment target layer exposure machine is first specified from the alignment mark measurement value in the shot.
Therefore, a non-linear error is calculated from the alignment mark measurement value in the shot by statistical processing (multipoint EGA calculation method). Since the non-linear error in the shot is considered to be affected by the lens distortion of the exposure machine, it is necessary to identify which projection lens (exposure machine) was used to expose the alignment target layer from the distribution state. You can Then, based on the identified distortion data of the projection lens, at least one of the projection magnification and the shot rotation obtained from the alignment mark measurement value in the shot can be corrected.

That is, according to the present invention, a step of measuring a plurality of alignment mark positions in a shot area in an exposure method in which a reticle pattern is sequentially superposed on a plurality of shot areas aligned on a substrate to be projected and exposed. And a step of correcting at least one of the projection magnification of the reticle pattern and the rotation of the projected image by using the measured alignment mark position and the distortion data of the projection lens used for forming the alignment mark.

The present invention also provides a step of measuring a plurality of alignment mark positions in a shot area in an exposure method in which reticle patterns are sequentially superimposed and projected onto a plurality of shot areas aligned on a substrate to be processed. , A step of calculating an error between the alignment mark position and the design position measured in the step, a step of extracting a non-linear component of the error, and a distortion of a known projection lens and the non-linear component of the extracted error Specifying the projection lens used for forming the alignment mark based on the data, and using the measured alignment mark position and the distortion data of the specified projection lens, the projection magnification of the reticle pattern and the rotation of the projection image. And a step of correcting at least one of the above.

According to the present invention, the shot magnification and the rotation of the process wafer are obtained in consideration of the distortion of the projection lens of the exposure machine used for exposing the alignment target layer, so that the overlay accuracy in the shot between the devices can be improved. It is possible to improve.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of an exposure method according to the present invention will be described below with reference to the drawings. In this embodiment, the present invention is applied to an exposure apparatus (stepper) that exposes a reticle pattern to each shot area on a wafer as a photosensitive substrate by a step-and-repeat method.

FIG. 2 shows the exposure apparatus of this example. In FIG. 2, the exposure light IL emitted from the illumination optical system 1 illuminates the reticle 2 with a substantially uniform illuminance. The reticle 2 is held on a reticle stage 3, and the reticle stage 3 is supported so as to be movable and minutely rotatable within a two-dimensional plane on a base 4. A main control system 6 that controls the operation of the entire apparatus controls the operation of the reticle stage 3 via a drive device 5 on the base 4.

Under the exposure light IL, the pattern image of the reticle 2 is projected onto each shot area on the wafer 8 via the projection optical system 7. The wafer 8 is placed on the wafer stage 10 via the wafer holder 9. The wafer stage 10 moves the wafer 8 in a plane perpendicular to the optical axis of the projection optical system 7.
XY stage and projection optical system 7 for two-dimensionally positioning
The Z stage for positioning the wafer 8 in the direction (Z direction) parallel to the optical axis of, and the stage for minutely rotating the wafer 8 and the like.

A movable mirror 11 that moves together with the stage is fixed on the upper surface of the wafer stage 10, and the movable mirror 11
The laser interferometer 12 is arranged so as to face the. Although it is simplified in FIG. 2, the projection optical system 7
The movable mirror 11 is composed of a plane mirror having a reflecting surface perpendicular to the X-axis and a plane mirror having a reflecting surface perpendicular to the Y-axis, with an orthogonal coordinate system in the plane perpendicular to the optical axis of the X axis and the Y axis. . Further, the laser interferometer 12 includes two laser interferometers for X-axis that irradiate the moving mirror 11 with a laser beam along the X-axis and a Y-axis for irradiating the moving mirror 11 with a laser beam along the Y-axis. The laser interferometer is used for measuring the X coordinate and the Y coordinate of the wafer stage 10 with one laser interferometer for the X axis and one laser interferometer for the Y axis. The coordinate system (X, Y) composed of the X coordinate and the Y coordinate measured in this way is hereinafter referred to as a stage coordinate system or a stationary coordinate system.

Further, the rotation angle of the wafer stage 10 is measured by the difference between the measured values of the two laser interferometers for the X axis. X coordinate, Y measured by laser interferometer 12
Information on coordinates and rotation angle is supplied to the coordinate measuring circuit 12a and the main control system 6, and the main control system 6 monitors the supplied coordinates and drives the wafer stage 10 via the drive unit 13.
Control the positioning operation. Although not shown in FIG. 2, the reticle side is also provided with the same interferometer system as the wafer side.

An image forming characteristic control device 14 is mounted on the projection optical system 7. The imaging characteristic control device 14 adjusts, for example, the distance between predetermined lens groups in the lens groups forming the projection optical system 7, or adjusts the pressure of gas in the lens chamber between the predetermined lens groups. Thus, the projection magnification, the distortion, etc. of the projection optical system 7 are adjusted. Imaging characteristic control device 1
The operation of 4 is also controlled by the main control system 6.

In this embodiment, an off-axis alignment system 15 is arranged on the side surface of the projection optical system 7, and in this alignment system 15, the illumination light from the light source 16 is collimator lens 17, beam splitter 18, and mirror 1.
It is irradiated to the vicinity of the alignment mark 29 on the wafer 8 via 9 and the objective lens 20. In this case, the baseline amount, which is the distance between the optical axis 20a of the objective lens 20 and the optical axis 7a of the projection optical system 7, is measured in advance. And
The reflected light from the alignment mark 29 is reflected by the objective lens 2
0, the mirror 19, the beam splitter 18, and the condenser lens 21 irradiate the index plate 22 to form an image of the alignment mark 29 on the index plate 22. Index plate 2
The light transmitted through 2 passes through the first relay lens 23 to the beam splitter 24, and the light transmitted through the beam splitter 24 is imaged by the X-axis second relay lens 25X by the X-axis image pickup device 26X including a two-dimensional CCD. The light focused on the surface and reflected by the beam splitter 24 is
It is focused on the image pickup surface of the Y-axis image pickup device 26Y including a two-dimensional CCD by the second axis relay lens 25Y. An image of the alignment mark 29 and an image of the index mark on the index plate 22 are superimposed and formed on the image pickup surfaces of the image pickup devices 26X and 26Y, respectively. The image pickup signals of the image pickup devices 26X and 26Y are both supplied to the coordinate position measuring circuit 12a.

FIG. 3 shows the pattern on the index plate 22 of FIG. 2. In FIG. 3, an image 29P of the cross-shaped alignment mark 29 is formed in the central portion, and a linear pattern image 29XP of the image 29P intersects at right angles. And XP perpendicular to 29YP
Direction and YP direction are the wafer stage 1 of FIG.
It is conjugate with the X and Y directions of the stage coordinate system of 0. Then, two index marks 31A and 31B are formed so as to sandwich the alignment mark image 29P in the XP direction, and two index marks 32A and 32B are formed so as to sandwich the alignment mark image 29P in the YP direction.

In this case, the index marks 31A,
31B and the detection area 33 surrounding the linear pattern image 29XP
The image in X is picked up by the X-axis image pickup device 26X in FIG.
The image in the detection area 33Y surrounding the index marks 32A and 32B and the linear pattern image 29YP in the P direction is imaged by the Y-axis image sensor 26Y in FIG. Furthermore, the scanning directions when reading photoelectric conversion signals from the pixels of the image pickup devices 26X and 26Y are set to the XP direction and the YP direction, respectively, and by processing the image pickup signals of the image pickup devices 26X and 26Y,
Alignment mark image 29P and index marks 31A, 31
It is possible to obtain the amount of positional deviation between B and 32A, 32B in the XP and YP directions. Therefore, in FIG.
The coordinate measuring circuit 12a determines the stage coordinate system (X) of the alignment mark 29 based on the positional relationship between the image of the alignment mark 29 on the wafer 8 and the index mark on the index plate 22 and the measurement result of the laser interferometer 12 at that time. , Y), and the coordinate values thus measured are supplied to the main control system 6.

Next, the operation for aligning each shot area on the wafer 8 with the pattern image of the reticle 2 and exposing each shot area in this embodiment will be described. FIG. 4A shows the wafer 8 of this embodiment. In FIG. 4A, the orthogonal coordinate system (α,
A plurality of shot areas 27-n (n = 0,
, 1, ... Are arranged in a matrix, and chip patterns are formed in each shot area 27-n by exposure and development in the previous step. In FIG. 4, five shot areas 27-1 to 27-1 of the plurality of shot areas are shown.
Only 27-5 is shown as a representative.

A reference position is defined for each shot area 27-n. For example, when the reference position is the reference point 28-n at the center of each shot area 27-n, the design coordinate values of this reference point 28-n in the coordinate system (α, β) on the wafer 8 are ( C _Xn , C _Yn ). In addition, four alignment marks 29- for alignment are provided in each shot area 27-n.
n, 30-n, 34-n, and 35-n are provided together. In this case, each shot area 27-n is formed in parallel with the coordinate system (α, β) on the wafer of FIG.
Coordinate system (x, y) on the shot area as shown in (b)
Is set, the alignment marks 29-n, 30-
n, 34-n, 35- n coordinate system (x, y) on each coordinates of the design in the _{(S 1Xn, S 1Yn),} (S 2Xn, S
_2Yn ), ( _S3Xn , _S3Yn ) and ( _S4Xn , _S4Yn ).

Returning to FIG. 4A, the wafer 8 is placed on the wafer stage 10 of FIG. 2, and the reticle is projected onto each of a plurality of shot areas in which the chip pattern has already been formed by the step-and-repeat method. Exposure is performed by sequentially superimposing images. At this time, the correspondence relationship between the stage coordinate system (X, Y) that defines the movement position of the wafer stage 10 and the wafer coordinate system (α, β) is not necessarily the same as the relationship in the previous step. Therefore, from the design coordinate values (C _Xn , C _Yn ) of the reference point 28-n of each shot area 27-n with respect to the coordinate system (α, β), the stage coordinate system (X,
Even if the coordinates on Y) are obtained and the wafer is moved based on these coordinates, the shot areas 27-n may not be precisely aligned. Therefore, in the present embodiment, first, it is assumed that the alignment error is caused by the following four factors as in the conventional example. Wafer rotation: This is represented by the residual rotation error Θ of the wafer coordinate system (α, β) relative to the stage coordinate system (X, Y). Orthogonality of stage coordinate system (X, Y): This occurs because the feed of the wafer stage 10 in the X-axis direction and the Y-axis direction is not exactly orthogonal, and is represented by an orthogonality error W. Linear expansion and contraction in the α direction and β direction in the wafer coordinate system (α, β) (wafer scaling): This occurs because the wafer 8 expands and contracts as a whole due to a processing process or the like. This expansion / contraction amount is represented by wafer scaling Rx and Ry in the α direction and the β direction, respectively. However,
The wafer scaling Rx in the α direction is the ratio of the measured value between the two points in the α direction on the wafer 8 to the design value, and the wafer scaling Ry in the β direction is the measured value between the two points in the β direction and the design value. It shall be expressed as a ratio. Stage coordinate system (X,
Offset for Y): This is caused by the wafer 8 being displaced by a small amount with respect to the wafer stage 10 overall, and is represented by offset amounts O _X and O _Y.

When the error factors (1) to (3) are added,
Coordinate values on the design of the reference point (C _Xn, C _Yn) for shot area, the stage coordinate system to be positioned when actually exposed (X, Y) on the coordinates _{(C 'Xn, C' Yn} )
Is represented as follows.

[0034]

(Equation 4)

Here, the orthogonality error W and the residual rotation error Θ
When the first-order approximation is performed assuming that is a small amount, (Equation 4) is as follows.

[0036]

(Equation 5)

Up to this point, the accurate alignment of the reference position on each shot area 27-n (the reference point at the center of each shot area in this embodiment) has been described. However, even if the reference points of the shot areas are accurately aligned, the entire chip pattern in each shot area and the projected image of the reticle do not necessarily exactly overlap each other.

Next, the overlay error in each shot area will be described. As already explained, FIG.
(B), the arbitrary shot area 27-n on the coordinate system (x, y) coordinate values of the design on the (S _1Xn, S _1Yn) ~
The alignment mark 29 is located at the position (S _4Xn , S _4Yn ).
-N, 30-n, 34-n, 35-n are formed. In this example, it is assumed that the overlay error in each shot area is caused by the following factors. Rotation of chip pattern (chip rotation): This is because, for example, when the projection image of the reticle 2 is exposed on the wafer 8, the reticle 2 is rotating with respect to the stage coordinate system (X, Y), or the wafer stage. This occurs when yawing is mixed in the movement of 10, and is represented by a rotation error θ with respect to the coordinate system (x, y) of the shot area. Orthogonality error of chip: This is due to distortion of the pattern itself on the reticle 2 or the distortion (distortion aberration) of the projection optical system 7 when the projection image of the reticle 2 is exposed on the wafer 8. It is an error of orthogonality and is represented by an angular error w. Linear scaling of chips (chip scaling):
For example, it is caused by an error in the projection magnification when the projection image of the reticle 2 is exposed on the wafer 8, or the wafer 8 wholly or partially expands or contracts due to the processing process of the wafer 8. Here, the chip scaling rx in the x direction, which is the ratio between the measured value and the design value of the distance between two points in the x direction of the coordinate system (x, y) of the shot area, and the distance between the two points in the y direction, It is assumed that the y-direction chip scaling ry, which is the ratio between the actually measured value and the design value, represents the linear expansion / contraction in two directions.

For example, FIG. 5A shows a wafer 8A in which a rotation error and a magnification error occur in the chip pattern of each shot area 27-n formed in the previous step.
In (a), an example of a shot area in the case where there is no rotation error and magnification error is a shot area 36-6 surrounded by a broken line.
It is represented by 36-10. On the other hand, the shot areas 27-6 to 27-10 actually formed on the wafer 8A have different rotation angles and magnifications. These errors are
As shown in (b), the chip rotation error in which the shot area 27-n is inclined with respect to the original shot area 36-n, and the magnification of the shot area 27-n as shown in FIG. Can be separated into a chip scaling error different from the original magnification of the shot area 36-n.

However, in the example of FIG. 5, there is no orthogonality error w of the chip pattern, and the chip scaling rx in the x direction.
And the chip scaling ry in the y direction are equal to each other. When the above error factors (1) to (4) are added, the designed coordinate value on the shot area 27-n becomes (S _NXn , S
_NYn ) (N = 1 to 4) alignment marks 29-n,
3n, for 34-n, 35-n, the actual alignment to be shot area coordinate system (x, y) on the coordinate values in _{(S 'NXn, S' NYn} ) is expressed as follows.

[0041]

(Equation 6)

Here, when the linear approximation is performed assuming that the orthogonality error w and the rotation error θ are minute amounts, (Equation 6) is expressed by the following equation.

[0043]

(Equation 7)

In FIG. 4B, the array coordinate value of the reference point 28-n of the arbitrary shot area 27-n on the stage coordinate system (X, Y) is (C _Xn , C _Yn ). Therefore, the stage coordinate system (X, X) of the arbitrary alignment mark (29-n or 30-n) on the arbitrary shot area is
The design coordinate values (D _NXn , D _NYn ) on Y) are expressed as follows. However, as described above, the alignment marks 29-n to 35-n are distinguished by the value of N (1 to 4).

[0045]

(Equation 8)

The above three errors 1 to 3 occur when the chip pattern is printed on the layer on which the alignment mark of each shot area on the wafer 8 is printed. In reality, the alignment mark 29 is further affected by the error of the above-mentioned error caused by the processing process of the wafer 8.
-N, 30-n, 34-n, 35-n are the coordinates of the actual position on the stage coordinate system (X, Y) (F _NXn , F
_NYn ) (N = 1 to 4), this coordinate value (F _NXn , F
_NYn ) is expressed from ( _Equation 5) and ( _Equation 7) as follows.

[0047]

[Equation 9]

Next, in the present embodiment, in order to facilitate the application of the method of least squares, the wafer scaling Rx in the α direction and the wafer scaling Ry in the β direction in (Equation 9) are respectively set as new parameters Γx and It is expressed as in the following (Equation 10) using Γy. Similarly, x in (Equation 9)
The chip scaling rx in the direction and the chip scaling ry in the y direction are expressed as the following (Equation 10) using new parameters γx and γy, respectively.

[0049]

(Equation 10)

When (Equation 9) is rewritten by using the four parameters Γx, Γy, γx, and γy showing these new changes in linear expansion and contraction, (Equation 9) becomes approximately as follows. .

[0051]

[Equation 11]

In this (Equation 11), assuming that the two-dimensional vector is a matrix of 2 rows × 1 column, this (Equation 11) can be rewritten into a coordinate conversion equation using a conversion matrix as follows.

[0053]

(Equation 12)

However, each transformation matrix of (Equation 12) is defined as follows.

[0055]

(Equation 13)

That is, in (Equation 12), the matrix F _Nn of 2 rows × 1 column is represented by addition of the matrix AC _n , the matrix BS _Nn, and the matrix O. Ten error parameters Θ included in the transformation matrices A, B, and O in the coordinate transformation formula of (Equation 12),
W, Γx (= Rx-1 ), Γy, O X, O Y, θ, w, γ
x (= rx−1) and γy can be obtained by, for example, the method of least squares.

Next, referring to the flow chart of FIG.
An example of the alignment operation and the exposure operation based on the coordinate conversion formula of (Equation 12) will be described. In this embodiment, it is assumed that the exposure machine used for exposing the alignment mark on the wafer is known. First, in step 101 in FIG. 1, the wafer 8 to be exposed this time is loaded on the wafer holder 9 in FIG. A chip pattern is already formed in each shot area of the wafer 8 in the previous process. Further, as shown in FIG. 4B, in each shot area 27-n on the wafer 8, a known lens
4 for each exposure machine with distortion
Cross-shaped alignment marks 29-n, 30-n,
34-n and 35-n are formed. Further, the alignment of the reticle 2 is completed, and the X, X of the reticle 2 with respect to the Cartesian coordinates defined by an interferometer (not shown).
The amount of deviation in the Y and rotation directions is almost zero.

Here, due to the lens distortion peculiar to the alignment mark exposure machine, when the average projection magnification in the shot area is Me, the projection magnification Ma at the alignment mark position becomes Ma = Me + M1, and within the shot area. When the rotation of the average projected image of is Re,
The rotation of the projected image at the alignment mark position is Ra = Re
It is + R1. The amounts of M1 and R1 can be obtained from the lens distortion data.

Next, in step 102 of FIG. 1, the origin of the wafer 8 is set (pre-alignment). Thereafter, in step 103, using the off-axis alignment system 15 of FIG. 2, five or more alignment marks (29-n, 30-n, 34-n or 3) on the wafer 8 are aligned.
5-n) coordinate values (F) on the stage coordinate system (X, Y)
_Measure M _NXn , FM _NYn ). Since one alignment mark has two components in the X direction and the Y direction, the values of 10 or more parameters can be determined by actually measuring the coordinate values of 5 or more alignment marks. The alignment mark to be actually measured needs to be selected from three or more shot areas 27-n.
It is not necessary to select four alignment marks 29-n to 35-n from one shot area 27-n, and one alignment mark (29-n, 30-n) from each one shot area 27-n. , 34-n or 35-n) may be selected.

In this case, a plurality of selected wafers 8 are selected.
On the wafer 8 at the reference point 28-n of the shot area 27-n
Design coordinate values (C, C) on the coordinate system (α, β) of_Xn,
C_Yn) And each shot of the measured alignment mark
Design coordinate values in the coordinate system (x, y) on the area 27-n
(Relative coordinate value) (S_NXn, S_NYn) Is known in advance.
Therefore, in step 104, the right side of (Equation 10)
, The shot area to which the measured alignment mark belongs
Array coordinate values (C_Xn, C_Yn),as well as
Design relative to the reference point of the alignment mark
Coordinate value (S_NXn, S _NYn), The
Alignment mark is on stage coordinate system (X, Y)
Coordinate value (F_NXn, F_NYn).

[Equation 12] is satisfied by the least square method.
Add 10 error parameters (Θ, W, Γx, Γy,
O_X, O_Y, Θ, w, γx, γy). Specifically
Is the actually measured coordinate value (FM_NXn, FM_NYn) And so
Calculated coordinate value of (F_NXn, F_NYn) Difference (E_NXn, E_NYn)
Is considered to be an alignment error. Therefore, E_NXn= FM
_NXn -F_NXn, E_NYn= FM_NYn-F_NYnHas been established
You. Then, the alignment error (E_NXn, E
_NYn), That is, the sum of squares of 10 or more alignment errors
Partially differentiated with these 10 error parameters, and the value
Make equations such that
Solve 10 simultaneous equations to find 10 error parameters
Can be

Then, in step 105, (Equation 1
2) The reticle 2 is appropriately rotated through the reticle stage 3 in FIG. 2 or the wafer 8 is rotated so as to correct the rotation error θ of the chip rotation in the conversion matrix B of 2). Correct the rotation of the chip pattern with respect to the system (X, Y). This is (Equation 11)
It means that the reticle 2 or the wafer 8 is rotated in accordance with the rotation error θ that constitutes the element of the conversion matrix B indicated by. However, since the rotation error θ of the obtained chip rotation includes the error R1 peculiar to the alignment mark exposure machine as described above, the amount by which the reticle or wafer should be rotated is (θ−R
1).

When the wafer 8 is rotated, the wafer
C8 offset error (O_X, O_Y) May change
Therefore, the coordinate value of the alignment mark was measured again.
After that, the conventional normal multipoint EGA calculation is performed and the error parameter is
It is necessary to ask for data again. Therefore, for example, the wafer 8 is
When rotated by a degree (θ-R1),
On the wafer 8 as in the case of not considering the error in the turn.
Alignment marks for at least 3 shot areas
Remeasure the coordinate values in the stage coordinate system (X, Y).
Then, from the result, six error parameters (Θ, W,
Rx, Ry, O _X, O_Y) Value and calculate from this result
Positioning of each shot area based on the array coordinates
And perform exposure.

Next, although the orthogonality error w of the chip cannot be corrected in a strict sense, the error can be suppressed to a small value by appropriately rotating the reticle 2. Therefore,
It is also possible to optimize the rotation amount of the reticle 2 or the wafer 8 so that the sum of the absolute values of the rotation error Θ, the rotation error θ, and the orthogonality error w is minimized. Next, in step 106, the projection magnification of the projection optical system 7 is adjusted via the imaging characteristic control device 14 of FIG. 2 so as to correct the chip scaling error in the conversion matrix B of (Equation 12). This is the chip scaling rx (= 1 + γx) and ry (=) that form the elements of the conversion matrix B shown in (Equation 11).
1 + γy) means that the projection magnification of the projection optical system 7 is adjusted. However, the obtained chip scalings rx and ry include the errors rx1 and ry1 peculiar to the alignment mark exposure machine as described above. The errors rx1 and ry1 peculiar to this exposure machine can be obtained from the lens distortion data. Therefore, in step 106, the projection magnification of the projection optical system 7 is set to chip scaling (rx-rx1) and (ry).
Adjust according to -ry1).

Then, in step 107 of FIG.
Using the conversion matrices A and O including the elements consisting of the error parameters obtained in step 104, the design array coordinate value (C _Xn of the reference point 28-n of each shot area 27-n on the wafer 8 is calculated as follows. , C _Yn ), the calculated array coordinate values (G _Xn , G _Yn ) of the reference point 28-n on the stage coordinate system (X, Y) are obtained. However, as described above, when the wafer 8 side is rotated in order to correct the rotation error in step 105, each reference point 28-n is determined based on the coordinates of the alignment mark measured again.
The calculated array coordinate values (G _Xn , G _Yn ) on the stage coordinate system (X, Y) of are calculated.

[0066]

[Equation 14]

Then, in step 108, based on the array coordinates (G _Xn , G _Yn ) obtained by the calculation and the previously determined baseline amount, the reference point 28- of each shot area 27-n on the wafer 8 is formed. n is sequentially aligned with a predetermined position in the exposure field of the projection optical system 7 of FIG.
The pattern image of the reticle 2 is projected and exposed on the shot area 27-n. Then, after the exposure of all shot areas on the wafer 8 is completed, processing such as development of the wafer 8 is performed.

In this case, in this example, not only the conversion matrices A, O, and B shown in (Equation 12) but also the lens distortion of the alignment mark exposure machine is taken into consideration, and therefore, it is included in the alignment mark itself. The chip pattern of each shot area on the wafer and the projected image of the reticle pattern can be superimposed with high accuracy without taking in an error.

Next, an embodiment will be described in which the alignment mark exposure machine is unknown and the error contained in the alignment mark cannot be known in advance. In this case, from the measured values of the alignment marks in the shot area, error parameters Θ, W,
Rx (= 1 + Γx), Ry (= 1 + Γy), Ox, O
y, θ, w, rx (= 1 + γx), ry (= 1 + γy)
Ask for. The difference between the coordinate value of the alignment mark that should be on the stage coordinate system (X, Y) calculated from the coordinate value of the design by coordinate conversion using these error parameters and the actual coordinate value is the nonlinear component of the error. And The alignment mark exposure machine is identified by comparing the non-linear component of this error with the non-linear component of the error expected when the alignment mark is exposed by each exposure machine having a known lens distortion.

After that, in the same manner as in the above-described embodiment, the error inherent in the specified alignment mark exposure machine is subtracted, and the reticle or wafer is rotated to correct the rotation error θ of the chip rotation and perform the chip scaling. After adjusting the projection magnification of the projection optical system in accordance with rx and ry, the transformation matrixes A and O including the elements consisting of the error parameters are used to set the stage coordinate system (X, Y) of the reference point of each shot area. Find the calculated array coordinate values above. Then, based on the array coordinates obtained by calculation and the baseline amount obtained in advance, the reference point of each shot area on the wafer is sequentially aligned with a predetermined position in the exposure field of the projection optical system, The projection exposure of the pattern image of the reticle onto the shot area is repeated. Here, a method of identifying the alignment mark exposure machine will be described in detail. Now, as shown in FIG. 6, ten shot areas 40-n (n = 1
-10), four alignment marks 42-n, 43-n, 44-n, 4 in each shot area 40-n.
5-n (here, the four alignment marks are assumed to be provided at the four corners of the shot area),
Consider the case of performing multipoint measurement within a shot. The setting of the stage coordinate system (X, Y), the coordinate system on the wafer (α, β), and the coordinate system on the shot area (x, y) is the same as in the above embodiment, and the notation method of each coordinate is also the above. Same as the example. That is, a reference position is defined in each shot area 40-n, and if the reference position is the reference point 41-n at the center of each shot area 40-n, this reference point 41-n
The design coordinate values in the coordinate system (α, β) on the wafer 8 are represented by (C _Xn , C _Yn ), respectively. The coordinate system (x, y) on the shot area is set parallel to the coordinate system (α, β) on the wafer, and each shot area 40
Design coordinates on the coordinate system (x, y) of the four alignment marks 42-n, 43-n, 44-n, 45-n for alignment provided on the -n are (S _1Xn ,
S _1Yn ), (S _2Xn , S _2Yn ), (S _3Xn , S _3Yn ) and (S
_4Xn , S _4Yn ).

The multipoint EGA calculation is performed in the same manner as in the above embodiment, and the ten error parameters Θ, which are included in the transformation matrices A, B, O of the coordinate transformation equations shown in (Equation 12) and (Equation 13), W, Γx (= Rx-1 ), Γy, O X, O Y, θ,
w, γx (= rx−1), γy (= γy−1) are obtained by, for example, the method of least squares. Next, the amount of deviation () between the coordinate value (F _NXn , F _NYn ) of the alignment mark calculated by the coordinate conversion formula including the error parameter thus determined and the actually measured coordinate value (FM _NXn , FM _NYn ). R
_NXn , R _NYn ), that is, R _NXn = FM _NXn −F _NXn , R
_NYn = FM _NYn -F _{N Yn} is 10 shot areas 40-
Each alignment mark 42-in n (n = 1 to 10)
All n, 43-n, 44-n, and 45-n are calculated. In the expression, the shot areas 40-1 to 40-10 are distinguished by the value of n (1 to 10), and the value of N (1 to 4).
Alignment marks 42-n, 43-n, 44
-N and 45-n are distinguished.

The deviation amount (R _NXn , R _NYn ) obtained here is called a random error. Random errors are obtained for 10 shots within the wafer for each of the four positions in each shot area 40-n. In FIG. 6A, four alignment marks 42-n, 43- provided on the shot areas 40-1 to 40-n, respectively.
Random errors (R _NXn , R _NYn ) at the positions of n, 44-n, 45-n are schematically shown as a vector. Random error in the shot (RE _NX , RE
_NY ). That is, in the present case, RE _NX = ΣR _NXn /
10, RE _NY = ΣR _NYn / 10 (N = 1 to 4).
FIG. 6B shows the random error (RE
_1X , RE _1Y ), (RE _2X , RE _2Y ), (RE _3X , R
E _3Y ) and (RE _4X , RE _4Y ) are displayed in vector.

On the other hand, the distortion data of the projection lens of the full exposure machine is obtained in advance. This distortion data consists of, for example, distortion data for 17 points in the shot area, and is stored in the exposure apparatus that performs overprinting. Alternatively, it is possible to centrally manage the distortion data of all exposure machines and inquire online if necessary.

With respect to the distortion data of each projection lens of each exposure machine, Θ = 0, W = 0, Γ
x = 0, Γy = 0, O _X = 0, O _Y = 0, the same calculation as the multipoint EGA calculation is performed centering on the shot center, and error parameters θ, w, γx (= rx−
1) and γy (= ry−1) are obtained, the distortion value at the alignment mark position calculated from the coordinate conversion formula including this error parameter is compared with the actual distortion data, and the distortion of four points is calculated as the difference.・ Random error (DRE _NXm , DRE _NYm ) (N =
1-4) is calculated. Here, m is a number (m = 1, 2, 3, ...) For identifying the exposure machine.

Next, the in-shot random error (RE _NX , RE _NY ) (N = 1 to 4) previously obtained and the distortion / random error (DRE) of the projection lens of each exposure machine are calculated.
_NXm , DRE _NYm ) (N = 1 to 4) and select the closest projection lens. This comparison can be performed by the following method, for example. Vector X _N (N =) of random error data (RE _NX , RE _NY ) in shot
1 to 4), the vector of distortion random error (DRE _NXm , DRE _NYm ) is set to l _Nm (N = 1 to 1).
It is represented by 4). The angle formed by the vectors X _N and l _Nm is θ _Nm (N =
When 1-4), the conditions for vector X _N, l _Nm is short, small vector X _N, the angle theta _Nm of l _Nm, and, by difference in length between X _N, l _Nm is small is there. As a result, S _Nm = | X _N −1 _Nm | (N = 1 to
Find 4). Taking their sum _{ΣS Nm = Σ | X N -l} Nm | (N = 1~4) The lower the value, the data (RE _NX, RE
It is shown that the degree of coincidence between the vector X _{N of NY} ) and the vector l _Nm of the distortion random error (DRE _NXm , DRE _NYm ) is high. Therefore, the equation ΣS _Nm is calculated for the distortion data of all exposure machines (m = 1, 2, 3 ...) As a comparison target, and the one having the smallest value is found.

The alignment mark exposure machine is specified by the above-mentioned method, and the distortion data (DRE _NXm , DRE _NYm ) ( _NRE of the projection lens of the exposure machine is specified.
= 1-4) is selected. Then, the lens magnification error M1 and lens rotation R1 peculiar to the exposure machine at the alignment mark position can be calculated from the distortion data of the identified alignment machine exposure machine.

Next, referring to the flowchart of FIG.
The alignment operation and exposure operation of this embodiment will be described. First, similarly to the above-described embodiment, in step 201, the wafer 8 to be exposed this time is loaded on the wafer holder 9 in FIG. A chip pattern is already formed in each shot area of the wafer 8 in the previous process. Furthermore, each shot area 4 on the wafer 8
Four cross-shaped alignment marks 42-n, 43-n, 44-n, and 45-n are formed at 0-n by an exposure machine having an unknown lens distortion. Further, the alignment of the reticle 2 is completed, and the amount of deviation in the X, Y and rotation directions of the reticle 2 with respect to the Cartesian coordinates defined by an interferometer (not shown) is almost zero.

Next, in step 202, the origin of the wafer 8 is set (pre-alignment), and then step 203
The off-axis alignment system 15 of FIG.
By using the coordinate values (FM _NXn , F) of the five or more alignment marks (42-n, 43-n, 44-n or 45-n) on the wafer 8 on the stage coordinate system (X, Y).
M _{NY n} ) is actually measured. Design reference coordinate values (C _Xn , C) of the reference points 41-n of the plurality of shot areas 40-n selected on the wafer 8 on the coordinate system (α, β) on the wafer 8.
_Yn ) and the designed coordinate value (relative coordinate value) (S _NXn , S _NYn ) of the measured alignment mark on each shot area 40-n in the coordinate system (x, y) are known in advance. Therefore, in step 104, in the same way as in the above embodiment, the designed array coordinate value (C
_Xn , C _Yn ) and the relative coordinate values (S _NXn , S _NYn ) in the design regarding the reference point of the alignment mark are substituted to calculate that the alignment mark should be on the stage coordinate system (X, Y). Upper coordinate value (F _NXn ,
F _NYn ).

Then, the equation (12) is satisfied by the least squares method.
Add 10 error parameters (Θ, W, Γx, Γy,
O_X, O_Y, Θ, w, γx, γy). Specifically
Is the actually measured coordinate value (FM_NXn, FM_NYn) And so
Calculated coordinate value of (F_NXn, F_NYn) Difference (E_NXn, E_NYn)
Is considered to be an alignment error. Therefore, E_NXn= FM
_NXn -F_NXn, E_NYn= FM_NYn-F_NYnIt is. Soshi
And more than 5 sets ment error (E_NXn, E_NYn), That is, 10
The sum of squares of the above alignment errors is the 10 errors
Partially differentiated with parameters, and each value becomes 0
Create an equation like this and solve these 10 simultaneous equations
If flickering, 10 error parameters can be obtained. This
The procedure up to this point is exactly the same as in the above embodiment.

Next, at step 205, a random error (R _NXn , R) which is a deviation amount between the coordinate value of the alignment mark calculated by the coordinate conversion formula including the obtained error parameter and the actually measured coordinate value. _NYn ) is obtained for all shot areas and averaged at each alignment mark position in the shot area, and the random error in shot (RE _NX , RE _NY ) (N =) shown in FIG.
1) to 4) are calculated.

In step 206, for all the exposure machines, the same calculation as the multipoint EGA calculation is performed with respect to the known distortion data of the projection lens centering on the shot center to obtain the error parameter within the shot area, The distortion random error (DRE _NXm , DRE _NYm ) at the alignment position is obtained by comparing the distortion value calculated from the coordinate conversion formula including the error parameter with the actual distortion data.

In step 207, the measured random error in shot (RE _NX , RE _NY ) and the distortion random error (DRE) of the projection lens of each exposure machine are measured.
_NXm , DRE _NYm ) and selects a projection lens lens that produces a random error closest to the actual random error. Next, in step 208, using the distortion data (DRE _NXm , DRE _NYm ) of the projection lens of the alignment mark exposure machine thus identified,
A lens magnification error M1 and a lens rotation R1 peculiar to the exposure machine at the alignment mark position are calculated.

After that, as in the above embodiment, in step 209, the rotation error θ of the chip rotation obtained by the multipoint EGA calculation is corrected by the lens rotation R1 peculiar to the alignment exposure machine, (θ-R1). ) Rotate the reticle or wafer to move the stage coordinate system (X,
Correct the rotation of the chip pattern with respect to Y). Further, in step 210, the projection magnification of the projection optical system is set to the chip scaling rx, r obtained by the multipoint EGA calculation.
Chip scaling r obtained by subtracting lens magnification errors rx1 and ry1 peculiar to the alignment mark exposure machine from y
Adjust according to x-rx1 and ry-ry1.

Then, in step 211, by using the conversion matrices A and O including the elements composed of the error parameters obtained in step 204, the reference point 41- of each shot area 40-n on the wafer 8 is expressed in (Equation 14). By substituting the designed array coordinate values (C _Xn , C _Yn ) of n, the calculated array coordinate values (G _Xn , G) on the stage coordinate system (X, Y) of the reference point 41-n. _Yn ), and in step 212, based on the calculated array coordinates (G _Xn , G _Yn ), and the previously determined baseline amount, the reference point 41-of each shot area 40-n on the wafer 8 is obtained. n is sequentially aligned with a predetermined position in the exposure field of the projection optical system, and the pattern image of the reticle is projected and exposed on the shot area 40-n. Then, after exposure of all shot areas on the wafer is completed, processing such as development of the wafer is performed.

Also in the present embodiment, since not only the conversion matrices A, O and B shown in (Equation 12) but also the lens distortion of the alignment mark exposure machine is taken into consideration, it is included in the alignment mark itself. The chip pattern of each shot area on the wafer and the projected image of the reticle pattern can be superimposed with high accuracy without taking in an error.

In any of the above embodiments, the wafers in the same lot may be regarded as having the same distortion because the alignment marks are formed by the same exposure machine. Therefore, it is not necessary to obtain random errors for all wafers and compare them with other distortion data, and the distortion data selected for the first wafer can be applied to the second and subsequent wafers. In addition, the non-linear error within the shot can be more accurately calculated by performing the multipoint EGA measurement for the entire shot area for the leading wafer.

Subsequently, the lens magnification of the 2nd layer exposure apparatus,
A correction method when the lens rotation is considered will be described. Lens magnification M1 and lens rotation R of the 1st layer exposure apparatus
The shot magnification Me and the shot rotation Re obtained by subtracting 1 can be expressed by the following formulas as in the above. Me = Ma-M1 Re = Ra-R1 When the 2nd layer exposure apparatus is the same as the 1st layer exposure apparatus, the shot magnification and shot rotation target values are controlled as Me and Re.

The lens magnification and lens rotation obtained from the distortion at the alignment mark position of the 2nd layer exposure apparatus are M2 and R2, respectively. The lens magnification difference Md and the lens rotation difference Rd at the alignment mark position between the 1st layer exposure apparatus and the 2nd layer exposure apparatus are as follows. Md = M2-M1 Rd = R2-R1 When correcting the shot magnification and shot rotation of the 2nd layer, the lens magnification difference Md and the lens rotation difference Rd must be subtracted. Therefore,
The shot magnification and shot rotation target values are Mt and
Rt can be expressed by the following equation.

Mt = Me-Md = Ma-M1- (M2-
M1) = Ma-M2 Rt = Re-Rd = Ra-R1- (R2-R1) = Ra
-R2 When performing such correction, it is desirable that the alignment mark position and the vernier mark position are almost the same, or that the alignment is performed using the vernier mark itself.

The present invention is applicable not only to a step-and-repeat type exposure apparatus (for example, a reduction projection type stepper or an equal-magnification projection type stepper) but also a so-called step-and-repeat type stepper.
The present invention can be similarly applied to a scanning exposure type exposure apparatus. When the above-described alignment method is applied to a scanning type exposure apparatus such as a step-and-scan exposure type exposure apparatus, a predetermined offset (pattern size, pattern size, The scanning exposure is performed after the wafer is positioned at a position to which a value (uniquely determined according to the run-up section of the reticle and the wafer) is added.

As described above, the present invention is not limited to the above-mentioned embodiments, and various configurations can be adopted without departing from the gist of the present invention.

[0092]

According to the present invention, since the exposure apparatus can be adjusted by eliminating the error contained in the alignment mark itself, the projected image of the chip pattern of each shot area on the wafer and the projected image of the reticle pattern can be obtained. It is possible to superimpose with higher accuracy. In addition, multi-point EGA within the shot
By using the random error (non-linear error) calculated by performing the above, the exposure machine used for forming the alignment mark is specified. Therefore, even if the alignment mark exposure machine is unknown, it is possible to estimate the machine, so that distortion management for each wafer becomes unnecessary.

[Brief description of drawings]

FIG. 1 is a flowchart showing an alignment operation and an exposure operation to which an embodiment of a positioning method according to the present invention is applied.

FIG. 2 is a configuration diagram showing an example of a projection exposure apparatus in which an alignment operation and an exposure operation of the embodiment are performed.

FIG. 3 is an enlarged view showing an image of an alignment mark on the index plate of FIG.

4A is a plan view showing an example of an arrangement of shot areas on a wafer according to an embodiment, and FIG. 4B is an enlarged plan view showing the shot areas in FIG. 4A.

5A is a plan view showing an example of a wafer including a rotation error of a chip pattern and an error of a chip magnification, FIG.
FIG. 6 is an explanatory diagram of a chip rotation error, and FIG. 7C is an explanatory diagram of a chip magnification error.

FIG. 6A is a plan view showing an example of an arrangement of shot areas in a wafer, and FIG. 6B is an explanatory diagram of a random error in shot.

FIG. 7 is a flowchart showing an alignment operation and an exposure operation to which another embodiment of the alignment method according to the present invention is applied.

[Explanation of symbols]

 1 Illumination Optical System 2 Reticle 6 Main Control System 7 Projection Optical System 8 Wafer 10 Wafer Stage 12 Laser Interferometer 14 Imaging Characteristic Control Device 15 Off-Axis Alignment System 27-1 to 27-5, 27-n Shot Area 28- 1-28-5, 28-n Reference point 29-1 to 29-3, 29-n Alignment mark 30-1 to 30-3, 30-n Alignment mark 34-1 to 34-3, 34-n Alignment mark 35-1 to 35-3, 35-n Alignment mark 40-1 to 40-10, 40-n Shot area 41-1 to 41-10 Reference point 42-1 to 42-10, 42-n Alignment mark 43- 1 to 43-10, 43-n Alignment mark 44-1 to 44-10, 44-n Alignment mark 45-1 to 45-10, 45-n Alignment mark

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication H01L 21/30 527

Claims (2)

[Claims] 1. An exposure method for projecting and exposing a plurality of shot regions aligned on a substrate to be processed with a pattern of a reticle in sequence, the steps of measuring a plurality of alignment mark positions in a shot region; And a step of adjusting at least one of the projection magnification of the reticle pattern and the rotation of the projected image using the alignment mark position and the distortion data of the projection lens used to form the alignment mark. 2. An exposure method in which reticle patterns are sequentially superimposed and projected onto a plurality of shot areas aligned on a substrate to be processed, and a step of measuring a plurality of alignment mark positions in the shot area, and the step of A step of calculating an error between the measured alignment mark position and the design position, a step of extracting a non-linear component of the error, the non-linear component of the extracted error and the distortion data of the known projection lens based on At least one of the projection magnification of the reticle pattern and the rotation of the projection image using the step of identifying the projection lens used for forming the alignment mark and the measured alignment mark position and the distortion data of the identified projection lens. And a step of adjusting the exposure method.