JPH08279453A - Aligning method - Google Patents

Abstract

PURPOSE: To align each of shot regions on a wafer at a high accuracy in an alignment by the EGA method by reducing the influence of the jump shot. CONSTITUTION: The EGA computation is made by removing the m-th sample shot from N sample shots in order (step 105), a nonlinear component B(m, n) of each of alignment data including the m-th sample shot (step 106) the sample shot having the worst nonlinear component is removed (step 1107), similar operation is repeated about the remaining sample shots (steps 105-111), a value T1(m) of the nonlinear component B(m, N-1) normalized by a mean value (step 112), and the jump shot is specified on the basis of the value T1(m) (step 114).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used, for example, in manufacturing a semiconductor device or a liquid crystal display device by a photolithography process, and a wafer (or a reticle (or photomask, etc.) pattern coated with a photosensitive material (or It is suitable for use in an exposure apparatus such as a stepper that transfers and exposes each shot area on a glass plate or the like) when sequentially aligning each shot area on a wafer with an exposure position based on array coordinates calculated by statistical processing. Regarding the alignment method.

[0002]

2. Description of the Related Art For example, since a semiconductor element is formed by exposing a plurality of layers of circuit patterns on a wafer and exposing the same, when projecting and exposing the circuit patterns of the second and subsequent layers onto the wafer, It is necessary to accurately align each shot area where a circuit pattern is already formed with the pattern of the reticle, that is, align the wafer and the reticle. Wafer alignment in an exposure apparatus such as a conventional stepper is performed by the following enhanced global alignment (hereinafter referred to as “EG
A method) (for example, JP-A-61-161)
44429).

That is, a plurality of shot areas (chip patterns) each provided with a positioning mark called a wafer mark are formed on the wafer, and these shot areas are set in advance on the wafer. They are regularly arranged based on the arrangement coordinates. However,
Even if the wafer is stepped based on the designed array coordinate values (shot arrays) of a plurality of shot areas on the wafer, the wafer is not always accurately aligned due to the following factors.

(1) Remaining rotation error of wafer (rotation θ) (2) Orthogonality error of stage coordinate system (or shot array) w (3) Linear expansion and contraction of wafer (scaling Rx, Ry) (4) Wafer (center Position) offset (translation) O
x, Oy At this time, these four error amounts (6 conversion parameters)
The coordinate conversion of the wafer based on can be described by a linear conversion formula.
Therefore, for a wafer in which a plurality of shot areas with wafer marks are regularly arranged, the coordinate system (x, y) on the wafer is used as a stationary coordinate system and the coordinate system (X, Y) on the stage is used. The primary conversion model to be converted into can be expressed as follows using these six conversion parameters. However, the approximation is performed assuming that the absolute values of the angles θ and w are small.

[0005]

[Equation 1]

The six conversion parameters Rx, Ry, θ, w, Ox, Oy in this conversion equation are EG as follows:
It can be determined by the A method. In this case, some shot areas (chip patterns) to be exposed on the wafer are selected (hereinafter,
The design coordinates on the coordinate system (x, y) associated with each of the “sample shots” are (x ₁ ,
The wafer marks y ₁ ), (x ₂ , y ₂ ), ..., (x _N , y _N ) are aligned with a predetermined reference position. Then, the actual coordinate values (XM ₁ , YM ₁ ) of the wafer mark at that time in the coordinate system (X, Y) on the stage, (XM ₂ , YM ₂ ) ,.
M _N , YM _N ) is measured.

Also, in designing the selected wafer mark
Array coordinates of (x_i, Y_i) (I = 1, ..., N)
Calculated array coordinates obtained by substituting into the linear transformation model of
(X _i, Y_i) And the coordinates (X
M_i, YM_i) And the difference (△ x_i, △ y_i)
Think of it as an error. And then align as
The error sum of squares is regarded as the residual error component, and this residual error
The values of those 6 conversion parameters to minimize the minutes
Determine.

[0008]

[Equation 2]

Specifically, the residual error component is sequentially partially differentiated with six conversion parameters, an equation is set so that the value becomes 0, and the six simultaneous equations are solved to obtain six conversions. The value of the parameter is calculated. The calculation for obtaining the six conversion parameters of (Equation 1) by the method of least squares is called "EGA calculation". After this, the alignment of each shot area of the wafer can be performed based on the array coordinates calculated using the primary conversion formula (Equation 1) using those conversion parameters as coefficients.

For example, FIG. 6A shows an example of eight sample shots SA _{1 to} SA ₈ on the wafer and vectors V _{1 to} V ₈ of alignment error in these sample shots, and each vector V _{1 to} V ₈ is shown. Is a vector obtained by subtracting the design coordinates from the respective measured coordinates. Further, FIG. 6B shows the number of sample shots measured, the average value of the X component and the Y component of the alignment error, three times the standard deviation of the X component and the Y component (3σ),
An error from 1 of the scaling Rx and Ry representing a linear error, an orthogonality error w, and a value of rotation θ are shown.

Further, FIG. 6C shows three times (3σ) the standard deviation of the linear error in the X direction and the Y direction obtained for each sample shot from the conversion parameters Rx, Ry, w, θ, Ox, Oy. 6D shows the value of 3 times (3σ) the standard deviation of the nonlinear error component in the X direction and the Y direction obtained for each sample shot. The linear error in FIG. 6C is an error vector obtained by subtracting the design coordinates (x _i , y _i ) from the calculation coordinates (X _i , Y _i ) calculated from (Equation 1). The non-linear error shown in FIG. 6D is calculated from the coordinates (XM _i , YM _i ) actually measured on the stage coordinate system (Equation 1).
This is an error vector obtained by subtracting the calculated coordinates (X _i , Y _i ) from the calculation, that is, an error vector obtained by subtracting the linear error from the alignment error.

In this case, in the sample shot of FIG.
Vector of linear error VL₁~ VL ₈As shown in Figure 7
It has become. That is, as shown in FIG.
It has a larger absolute value than other error vectors in the cutle.
Exact linear error vector if not included
You get

[0013]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the A-type alignment method, the plurality of sample shots may include a so-called “jump shot” in which the alignment error is particularly large compared to other sample shots. Since such a jump shot is caused by a measurement error caused by a collapse of a wafer mark attached to the sample shot on the wafer, or a local non-linear distortion caused by a foreign substance on the back surface of the wafer, When calculating the array coordinates of other shot areas, it is desirable to exclude such jump shots.

For example, FIG. 8A shows eight sample shots SA _{1 to} SA ₈ including jump shots on the wafer.
And other examples of the alignment error vectors V _{1 to} V ₈ in these sample shots are shown in FIGS.
7D corresponds to FIGS. 7A to 7D, respectively.
In FIG. 8A, the sample shot SA ₃ is a jump shot, and the absolute value of the alignment error vector V _{3 in} this jump shot is particularly large. In this case, the vector of the linear error obtained by subtracting the design coordinates (x _i , y _i ) from the calculation coordinates (X _i , Y _i ) calculated from (Equation 1) is the vector of FIG. V
Like L _{1 to} VL ₈ , it appears that the error vector V _{3 of} FIG. 8 has been mutated into two linear error vectors VL ₃ and VL ₆ . This means that if the EGA calculation is performed with the jump shot included, the linear error in the position of the shot area other than the jump shot increases.

Further, in order to exclude jump shots, for example, when those in which the absolute value of the non-linear error component is larger than a predetermined threshold are excluded as jump shots, the jump shots vary depending on how the thresholds are determined. For example, it is desirable that the evaluation standard for selecting the jump shot is automatically determined to some extent automatically according to the actual measurement result of the array coordinates of the sample shot.

Further, since the absolute value of the non-linear error component may be large due to the actual linear expansion and contraction of the wafer instead of the jump shot, the sample shot having the large absolute value of the non-linear error component is simply taken as the jump shot. However, if it is excluded as, there is a possibility that the final alignment accuracy may deteriorate. In view of the above problems, the present invention reduces the influence of jump shots and accurately adjusts each shot area (processed area) of a wafer (substrate) when performing alignment by applying a statistical processing method such as the EGA method. region)
It is an object of the present invention to provide a position aligning method capable of setting the respective exposure positions to predetermined exposure positions.

Another object of the present invention is to provide a positioning method capable of automatically determining an evaluation standard for specifying a jump shot.

[0018]

According to a first alignment method of the present invention, a plurality of regions to be processed (ES ₁ , ES ₂ , ..., ES) arranged on a substrate (4) in accordance with design arrangement coordinates are provided.
The array coordinates on a predetermined coordinate system (X, Y) that defines the moving position of the substrate (4) of ( _M ) are respectively obtained, and based on the array coordinates thus obtained, each of the plurality of processed regions is determined. In the method of aligning to a corresponding processing position, a predetermined coordinate system (X) of N (N is an integer of 6 or more) sample areas (SA _i ) selected in advance from the plurality of processing areas is used. , Y) first measuring coordinate position on
From the step (step 101) and the coordinate position data of the n (n is an integer of initial value N) sample areas measured in the first step, the m-th (m is an integer of initial value 1) sample area is selected. Based on the result obtained by statistically processing the excluded (n-1) coordinate position data, the nonlinear error component of each coordinate position data including the m-th sample area, and the n nonlinear error Component variation B (m, n-
The second step (steps 105 and 106) for obtaining 1).

Further, according to the present invention, the third step (step 107) for obtaining (n-2) sample areas excluding the sample area having the largest non-linear error component obtained in the second step, and this third step. Until the sample area left in the third step reaches a predetermined lower limit value N _min , the second step and the third step
The fourth process (steps 105 to 105) is repeated to obtain the variation B (m, n-1) of each non-linear error component.
109) and increasing the value of the integer m by 1 from 1 to N, repeating the second step to the fourth step, respectively, and then varying the nonlinear error component variation B (m, n−
1), and this variation B (m, n-1) is used as a variable (n
−1) is a mean value in a range in which (N−1) changes from (N−1) to N _min , and a value T1 obtained by normalizing the variation B (m, N−1)
Fifth step (steps 105 to 112) for obtaining (m)
And a sixth step (step 114) of detecting a sample region having a large non-linear component of the measurement result by comparing the N values T1 (m) obtained in the fifth step, and the sixth step. A seventh step of statistically processing measured coordinate position data of the N sample areas including the sample area to calculate array coordinates of the plurality of processed areas on the predetermined coordinate system (X, Y). (Steps 116-118)
And ,.

In this case, the fifth step (step 105)
, 112), the variable (n-1) is changed from (N-2) to N when the value of the integer m is increased from 1 to N for the variation B (m, n-1) of the nonlinear error component.
Variations B (m, N-1) and B (m, N-) are average values of the variation B (m, n-1) in the range changing to _min.
Value T2 (m1, m2) obtained by normalizing the sum of 2)
(Integers m1 and m2 indicate the order of the sample areas removed at this time) (step 113), and in the sixth step, the N values T obtained in the fifth step are calculated.
It is desirable to detect a sample area having a large nonlinear error component by comparing 2 (m1, m2).

Further, in the sixth step, by detecting the N values T1 (m) and the N values T2 (m1, m2), a sample area having a large non-linear error component is detected. Is desirable. Further, in the seventh step, the measured coordinate position data of the remaining sample areas excluding the sample areas detected as having a large non-linear error component in the sixth step are statistically processed to calculate the plurality of processed areas. You may make it calculate the array coordinate on a predetermined coordinate system (X, Y).

Alternatively, in the seventh step, the measured coordinate position data of each of the N sample areas is reduced so that the weight of the sample area detected as a large non-linear error component in the sixth step becomes small. You may make it calculate the arrangement | positioning coordinate on the predetermined coordinate system (X, Y) of these some to-be-processed areas by attaching a weight and performing statistical processing.

When weights are used in this way, N
The N values T1 (m) or the values corresponding to the reciprocals of the N values T2 (m1, m2) may be used as the weights to be given to the measured coordinate position data of the sample areas. . In addition, the second alignment method of the present invention uses the same premise as that of the first alignment method.
Preselected N (N
Is an integer greater than or equal to 6) a first step (step 101) of measuring the coordinate position of a sample area (SA _i ) on a predetermined coordinate system (X, Y), and N pieces measured in this first step. From the coordinate position data of the sample area of, the m-th (m is the initial value 1
(N-1) coordinate area data excluding the sample area is statistically processed to obtain conversion parameters from the designed array coordinates to array coordinates on a predetermined coordinate system (X, Y). , The array parameters on the predetermined coordinate system (X, Y) of the N sample areas are calculated using the conversion parameters thus obtained and the array coordinates on the design, and the array coordinates are calculated in this way. A second step (steps 105 and 106) of obtaining the variation B ′ (m, N−1) of the non-linear error component of the N array coordinates.

Further, according to the present invention, the second step is repeated while increasing the value of the integer m by 1 to N, and the third step of obtaining the non-linear error component variation B '(m, N-1). (Steps 105 to 111) and the second
A third step (step 114) of detecting a sample area having a large non-linear component of the measurement result by comparing the process and the variation B ′ (m, N−1) of the N non-linear error components obtained in the third step. And statistically processing the measured coordinate position data of the N sample areas including the sample area detected in the third step, and performing the statistical processing on the predetermined coordinate system (X, Y) of the plurality of processed areas. And a fourth step (steps 117 and 118) of calculating the array coordinates of.

The third alignment method of the present invention is
In the same premise as in the first alignment method, N preselected (N is 6
A first step (step 101) of measuring the coordinate position of a sample area (SA _i ) of the above integer) on a predetermined coordinate system (X, Y), and N samples measured in this first step The second step (steps 105 to 114) of processing the coordinate position data of the area to obtain a sample area having a large non-linear error component as the jump area and the N coordinate position data measured in the first step. Arrangement of a plurality of regions to be processed on a predetermined coordinate system (X, Y) by statistically processing the N coordinate position data weighted in this way by giving weights that are small in the jump region. And a third step (steps 121 and 122) of calculating coordinates.

[0026]

According to the first alignment method of the present invention, the number of jump regions (jump shots) having a large absolute value of the nonlinear error component on one substrate is usually 1 at most.
Paying attention to the fact that the number is one or two, the jump shot is detected from the sample area (SA _i ) to be measured on the substrate (4) as follows. That is, first, assuming that the number of jump shots is one, the first sample area is assumed to be a jump shot.

In this case, the coordinate position data of the first (m = 1) th sample area (sample shot) is first removed, and statistics are obtained using the coordinate position data of the remaining (n-1) sample areas. When the processing (EGA calculation or the like) is performed, since the remaining coordinate position data has many accurate data, the coordinate conversion parameters and the like can be accurately obtained. Therefore,
When the non-linear error component of the coordinate position data of the n sample areas including the first is obtained using the coordinate conversion parameter and the like, the variation B () of the obtained non-linear error component is large because the first non-linear error component is large. The value of 1, n-1) becomes large. Further, the variation B (1, n-2), B (1, n-) of the nonlinear error components calculated by sequentially removing the ones having large nonlinear error components from the remaining coordinate position data.
2), ..., B (1, N _min ) is the average value and the variation B is
Since the value T1 (1) obtained by normalizing (1, n-1) is obtained, the reliability of the value T (1) which is the data to be compared is high.

Next, the coordinate position data of the 2 (m = 2) th sample area is removed, and the statistical processing is performed using the coordinate position data of the remaining (n-1) sample areas.
In this case, since the first coordinate position data, which is a jump shot, is included in the first calculation, the variations B (2, n-1), B (2, n-2), of the obtained nonlinear error components are
, B (2, N _min ) is an average value, and the variation B (2, n−
The value T1 (2) obtained by normalizing 1) becomes small. Similarly 3
Value T1 obtained by excluding the sample areas after the th
(3), ..., T1 (N) also becomes small. Therefore, 1 is removed when the largest value T1 (1) is finally obtained from the N average values T1 (1), ..., T1 (N).
The second sample area is specified as a sample area having a large non-linear component (jump shot), and accurate alignment is performed by removing the jump shot, for example.

Next, when two jump shots are included on the substrate (4), it is assumed that the first and second sample areas are jump shots, respectively. At this time, the variations B (1, N-1), B of the nonlinear error components
The value of (1, N-2) becomes a relatively large value, and the variation B (1, N-2), ..., B (1, N _{mi of the} nonlinear error components
_{n is} the average value of variations B (1, N-1), B (1, N-
The value T2 (1,2) (m1 = 1, m
2 = 2) is a large value. The values T2 (m1, m2) of other combinations for the integers m1 and m2 are smaller than the values T2 (1, 2) because the coordinate conversion parameters and the like are calculated including the jump shot data. Therefore, the two sample areas removed when the maximum value T2 (m1, m2) is obtained are specified as the sample areas (jump shots) having a large non-linear component. The registration is performed. However, when the value T2 (m1, m2) is the maximum, the value T2 (m2, which is obtained by interchanging the integers m1 and m2)
Since m1) should be the second largest, it may be determined that, for example, two jump shots do not exist when this is not established.

In these cases, the number of jump shots is not known to be 0, 1, or 2, but N values T1 (m) and N values T2 (m1) are not known. , M
By comparing 2) with each other, the number of jump shots and the jump shots can be specified. Therefore, the evaluation standard for automatically specifying the jump shot is set.

Further, even if there is a sample area having a large non-linear error component, if the non-linear error component is small, if the non-linear error component is removed as a jump shot, there is a risk that the alignment accuracy will rather deteriorate. Therefore, if even the largest non-linear error component is smaller than the predetermined threshold value, each coordinate position data is weighted according to the average value T1 (m) of the non-linear error component or the reciprocal of T2 (m1, m2). , Statistical processing (eg weighted EG
The array coordinates are calculated by A calculation etc.).

Next, according to the second alignment method of the present invention, the m-th (m = 1,
After the sample areas of 2, ..., N) are removed and the coordinate conversion parameters and the like are calculated, the variation B ′ (m, N−1) of the nonlinear error component including the m-th sample area is obtained. For example, assuming that the first sample area is a jump shot, the value of the variation B ′ (1, N−1) becomes large, so that the jump shot is accurately specified without being affected by the value of the jump shot itself. . After that, for example, the measurement data of the jump shot is lightly weighted, and the array coordinates of each processed region are calculated by statistical processing using all the measurement data, whereby the influence of the jump shot is reduced.

Next, according to the third alignment method of the present invention, first, a sample area having a large nonlinear error component is specified as a jump area (jump shot). After that, for example, the measurement data of the jump shot is lightly weighted, and the array coordinates of each processed region are calculated by statistical processing using all the measurement data, whereby the influence of the jump shot is reduced.

[0034]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the alignment method according to the present invention will be described below with reference to the drawings. FIG. 3 shows a projection exposure apparatus in which the alignment method of this embodiment is used. In FIG. 3, the exposure illumination light IL from the illumination optical system 1 forms a uniform illuminance distribution on the pattern on the reticle 2. A reduced image of the pattern illuminated through the projection optical system 3 is exposed to each shot area on the wafer 4 coated with the photoresist. Here, Z is parallel to the optical axis AX of the projection optical system 3.
Take the axis and make X parallel to the plane of FIG.
Take the axis and take the Y axis perpendicular to the plane of the paper in FIG.

The wafer 4 is held on the wafer stage 6 via the wafer holder 5, and the wafer stage 6 is an XY stage for positioning the wafer 4 in the X and Y directions.
It is composed of a Z stage for moving the wafer 4 in the Z direction, a θ stage for rotating, a leveling stage for correcting the tilt angle of the wafer 4, and the like. A laser beam from an external biaxial laser interferometer 8 is reflected by a biaxial moving mirror 7 (only for the X axis is shown in FIG. 3) fixed to the upper surface of the wafer stage 6, and the laser beam is reflected. The X coordinate and the Y coordinate of the wafer stage 6 are constantly measured by the interferometer 8. The coordinate system determined based on the coordinates (X, Y) measured by the laser interferometer 8 in this way is called a stage coordinate system or a stationary coordinate system. The measured coordinates (X, Y) are supplied to the main control system 9 that governs the operation of the entire apparatus, and the main control system 9 based on the measured coordinates,
The positioning operation of the wafer stage 6 is controlled via the wafer stage drive system 10.

In general, a semiconductor device or the like is manufactured by repeating the process of projecting and exposing the reticle pattern on each shot area on the wafer to perform development and the like 10 to 20 times. Therefore, the reticle to be exposed from now on. It is necessary to accurately align the pattern with the circuit pattern formed in each shot area of the wafer 4 in the steps up to that point. For this reason, in the projection exposure apparatus of FIG. 3, an off-axis type imaging system alignment system 11 for detecting the coordinates of wafer marks attached to each shot area on the wafer 4, and a TTL (through. An alignment optical system 15 of a laser step alignment method (LSA method) is provided. As the alignment optical system 15, an imaging method, a so-called two-beam interference method, or the like can be used, but in this embodiment, the LSA method is used as an example. Similarly, as the alignment system 11, the LSA method or the like can be used.

In this case, X is present in the alignment system 11.
The image pickup devices for the axis and the Y-axis are incorporated, and the image pickup signals obtained by picking up the image of the wafer mark are supplied from the two image pickup devices to the image pickup signal processing system 14.
The coordinates (X, Y) measured by the laser interferometer 8 are also supplied to the imaging signal processing system 14, and the imaging signal processing system 14
Detects the X coordinate (Y coordinate in the case of a wafer mark for the Y axis) when the image of the wafer mark for the X axis to be detected matches a predetermined index mark, for example. Supply to. Thereby, the main control system 9 can recognize the coordinates (X, Y) of the wafer mark attached to the shot area of the measurement target of the wafer 4.

On the other hand, the laser beam for detection emitted from the alignment optical system 15 enters the projection optical system 3 via the mirror 16 for bending the optical path, and the laser beam passing through the projection optical system 3 is shown in FIG. As shown in b), it is condensed on the wafer 4 as a slit-shaped light spot 17 which is long in the Y direction. The wafer stage 6 of FIG. 3 is driven to move the light spot 17 so as to traverse the wafer mark Mx _i for the X axis to be detected on the wafer 4 in the X direction.
Wafer mark Mx _i are those had been chosen plurality of rows of patterns each of which is made of a row of dots arranged at a predetermined pitch in the Y direction in the X direction, the wafer mark Mx _i the light spot 1
Since the diffracted light is emitted in a predetermined direction when crossing 7, the X coordinate of the wafer mark Mx _i is detected.

Returning to FIG. 3, a light spot 17 on the wafer 4 is obtained.
The diffracted light from the wafer mark returns to the alignment optical system 15 via the projection optical system 3 and the mirror 16, and the alignment signal obtained from the alignment optical system 15 to the alignment signal processing system 18 by photoelectrically converting the diffracted light. Is supplied. The coordinates (X, Y) measured by the laser interferometer 8 are also supplied to the alignment signal processing system 18, and when the light spot 17 is at the center position of the wafer mark for the X axis, the alignment signal processing system 18 is supplied. The X coordinate of is detected and supplied to the main control system 8. An Y-axis alignment optical system (not shown) is also provided, and the alignment optical system and the alignment signal processing system 18 detect the Y-coordinate corresponding to the Y-axis wafer mark. It is supplied to the main control system 8.

As a basic alignment operation of the projection exposure apparatus of this example, first, the wafer 4 is moved to the wafer holder 5 shown in FIG.
When loaded on top, the main control system 9 moves the wafer 4 through the wafer stage drive system 10 and the wafer stage 6 in XY direction.
By moving in the plane, the wafer mark attached to the sample shot on the wafer 4 is set near the position where the optical spot is irradiated from the alignment optical system 15 (or the alignment optical system for the Y axis). In this case, the positioning (pre-alignment) of the wafer 4 is performed based on the coordinates of each shot area defined on the coordinate system on the wafer 4, for example. Then, by moving the wafer 4 in the X direction or the Y direction, the alignment signal processing system 18 measures the coordinates of the wafer mark with high accuracy. The main control system 9 calculates the array coordinates in the stage coordinate system (X, Y) of all shot areas on the wafer 4 as described later using the coordinates of the wafer marks of each sample shot thus measured. Then, based on the calculation result, the pattern image of the reticle 2 is exposed in each shot area by the step-and-repeat method. An off-axis type alignment system 11 may be used as the alignment system.

Next, the first embodiment of the alignment method (alignment method) according to the present invention will be described in detail. (A) Basic Alignment Method FIG. 4A shows an example of the shot arrangement of the wafer 4 of this example. In FIG. 4A, M pieces (FIG. 4) are arranged on the wafer 4.
In (a), M = 68) shot areas ES _{1 to} ES _M are arranged, a circuit pattern is formed in each shot area ES _j (j = _{1 to M} ), and the wafer mark Mx _j for the X axis is formed. , And a wafer mark My _j for the Y axis are attached. In this case, the x coordinate x of the center of each wafer mark Mx _j on the sample coordinate system (x, y) set on the wafer 4.
_j and the y coordinate y of each wafer mark My _j for the Y axis
_j is previously stored in the storage device of the main control system 9 in FIG. 3 as design coordinates. Below, the x coordinate of the center of the wafer mark Mx _j and the y coordinate of the center of the wafer mark My _j are regarded as the x coordinate and the y coordinate in the sample coordinate system of the center of the shot area ES _j , and the coordinates of the wafer mark are Considered as the coordinates of the shot area. Actually, there is generally an offset between the center coordinate of the wafer mark and the center coordinate of the corresponding shot area, but the offset is ignored here for simplicity.

At this time, six conversion parameters (scaling Rx in the X direction, scaling Ry in the Y direction, rotation θ, orthogonality error w, and offset O in the X direction are used.
(Offset Oy in x and Y directions)
The conversion relationship from the sample coordinate system (x, y) to the stage coordinate system (X, Y) is defined by the conversion formula of. Then, in order to determine the values of those six conversion parameters, those M
N selected from the shot areas (4 ≦ N ≦ M)
Shot area, that is, N sample shots SA ₁ to
For SA _N, the wafer mark for the X coordinate XM _i, and Y-axis of the wafer mark for the X-axis, which is attached to each by using the alignment optical system 15 in FIG. 3 Y coordinate YM _i (i =
1 to N) are measured. The coordinates (XM
_i , YM _i ), a calculated array obtained by substituting the designed array coordinates (x _i , y _i ) (i = 1, ..., N) of the wafer mark of the sample shot into (Equation 1). Coordinates (X _i ,
Vector (Δx _i , Δy _i ) obtained by subtracting Y _i ).
Is the vector of alignment error.

Therefore, the designed array coordinates (x _i , y _i ) of each sample shot SA _i are converted into the coordinates (x, y) of (Equation 1).
As the array coordinates (X _i , Y) in the stage coordinate system (X, Y) of each sample shot.
_i ) is represented as a function of 6 conversion parameters and design array coordinates. Then, by EGA calculation, the sum of squares of the alignment errors of the N sample shots represented by (Equation 2), that is, the residual error component is minimized by the EGA calculation.
Determine the values of the transformation parameters.

After that, the six determined conversion parameters (Rx, Ry, θ, w, Ox, Oy) and the designed array coordinates (x _i , y _i ) of each sample shot SA _i are calculated by (Equation 1). ) To each sample shot SA _i
The final calculated array coordinates (X _i , Y _i ) are calculated. At this time, the vector obtained by subtracting the designed array coordinates (x _i , y _i ) from the calculated array coordinates (X _i , Y _i ) is the vector of the linear error component, and the measured coordinates (XM
_i, the arrangement coordinates (X _i on that calculated from YM _i), a vector obtained by subtracting the Y _i) is a vector of nonlinear error component. Then, in this example, a sample shot having a large absolute value of the vector of the nonlinear error component is regarded as a jump shot and excluded, and six conversions are performed by EGA calculation based on the array coordinates measured for the remaining sample shots. Define the parameters. Then, using (Equation 1), the array coordinates of all shot areas on the wafer are calculated, and each shot area of the wafer is sequentially positioned at the exposure position according to the array coordinates to perform exposure. A specific example of the jump shot removing method will be described below.

(B) Method for Removing Jump Shots A method for removing jump shots in this example will be described with reference to the flowchart in FIG. In this case, as an example, the shot arrangement on the wafer 4 is regarded as the arrangement shown in FIG. 5A, and 10 shots selected from those shot areas are selected.
The individual shot areas are sample shots SA _{1 to} SA ₁₀ . That is, the number N of sample shots is 10.
In the following example, the number N of sample shots is 6 or more.

First, in step 101 of FIG. 1, N
For each (N = 10) sample shots SA _{1 to} SA _N , coordinate values in the stage coordinate system (X, Y) are measured,
In step 102, the values of the six conversion parameters of (Equation 1) are determined by EGA calculation using the N measured coordinate values (alignment data) (XM _i , YM _i ).

Thereafter, in step 103, the calculated array coordinates (X _i , Y _i ) (i = 1) of each sample shot obtained by substituting the determined conversion parameter into (Equation 1).
˜N), the designed array coordinates (x _i , y _i ) are subtracted to obtain the linear component (linear error component) P of the alignment error. Then, from the measured coordinate values (alignment data) (XM _i , YM _i ), the calculated array coordinates (X _i , Y
_i ) is subtracted to obtain a vector (XM _i −X _i , YM _i −Y _i ) of the non-linear component (non-linear error component) of the alignment error.
Ask for. The worst value (maximum value) of the absolute values of the vectors of these N nonlinear components, or 3 times the standard deviation of the absolute values of the vectors of these N nonlinear components (this is NLE (3
σ)), and the worst value, or NLE (3σ)
Is a function R indicating the nonlinear component of the alignment data.

Next, the sample shots are sequentially removed one by one from the N sample shots in FIG. 5A. In preparation for that, in step 104, the variable m is set to 1 and the variable n is set to n. Be (N-1). In this case, the variable m indicates the order of the sample shots to be removed from the N sample shots, and the variable n indicates the number of remaining sample shots. For example, if the variable m is 1,
As shown in FIG. 5B, the first sample shot SA
_This means that the measurement data (alignment data) of 1 is removed. Next, in step 105, the remaining n pieces after removing the m-th sample shot (see FIG. 5B)
Then, using the alignment data of n = 9) sample shots, the values of the six conversion parameters of (Equation 1) are determined by EGA calculation. Then, in step 106, the deviation (alignment error) of the alignment data of the (n + 1) sample shots including the m-th sample shot from the design value is separated into a linear component and a non-linear component, respectively. The worst value (maximum value) of the absolute value of the vector of the linear component or three times the standard deviation is set as the linear component P (m). In addition, the worst value of the absolute value of the vector of n nonlinear components, or NLE (3
Let σ) be the non-linear component B (m, n).

After that, the alignment data of the sample shot having the largest absolute value among the vectors of the non-linear components of the n sample shots, that is, the non-linear component has the worst value, excluding the m-th sample shot obtained in step 106. (Step 107), the number (n-1) of the remaining sample shots is set to n again (step 108). Then, in step 109, it is determined whether or not the number n of the remaining sample shots is 4 or more. If the number n is 4 or more, step 10
5 to 109 are executed. That is, the EGA calculation is performed for one less sample shot than before, and (n +
1) After obtaining the linear component and the non-linear component of the alignment error of the sample shots and obtaining the linear component P (m) and the non-linear component B (m, n), the non-linear component is detected from the n sample shots. The worst sample shot is removed.

By repeating this, when the order m is 1, the nonlinear components B (1, N-1) and B (1, N-
2), B (1, N-3), ..., B (1, 4) are determined and stored. Further, as shown in FIG. 5C, for example, sample shots SA ₁ → SA ₃ → SA ₁₀ → SA ₆ → S
Assuming that the sample shots are removed in the order of A _4, the order of the sample shots thus removed is also stored.

When the number of sample shots n becomes 3 in step 109, the process proceeds to step 110,
It is checked whether the order m of the sample shots to be removed first has reached N. When the order m does not reach N, the order m is set to (m + 1), the value of the number n of the remaining sample shots is returned to (N-1) (step 111), and the state is set to the initial state again. The operations of steps 105 to 110 are repeated. As a result, the nonlinear components B (2, N-1), B (2, N-2), ..., B
(2,4) is required. Also, the order of sample shots to be removed is stored.

Further, steps 105 to 111 are repeated until the value of the order m of the sample shots to be removed first becomes N, so that N kinds of nonlinear components B (m, n) are obtained.
(M = 1 to N, n = (N-1) to 4), and the order of the sample shots removed at that time are obtained. Then, when the order m reaches the number N of sample shots in step 110, the process proceeds to step 112 and the value of the variable n is (N) for N non-linear components B (m, n).
The average value D1 (m) in the range from -1) to 4 is calculated. That is, the sum symbol Σ is as follows, which represents (N-1) to (N-4) sums of 4 for the variable n.

[0053]

## EQU00003 ## D1 (m) =. SIGMA.D (m, n) / (N-4) Furthermore, the nonlinear component B (m, N-1) in the sample shot removed first with respect to the average value D1 (m). A function T1 (m) indicating how large is is obtained from the following equation.

[0054]

## EQU00004 ## T1 (m) = B (m, N-1) / D1 (m) Next, the process proceeds to step 113, and the functions D2 (m1, m2) and T2 (assuming two jump shots are assumed). m1,
m2) is calculated. First, the function D2 (m1, m2) is N
For each non-linear component B (m, n), the value of the variable n is the average value in the range from (N-2) to 4, and the sum symbol Σ is from (N-2) to 4 for the variable n. (N-
5) The following is a representation of the sum.

[0055]

## EQU00005 ## D2 (m1, m2) =. SIGMA.B (m, n) / (N-5) In this case, the integer m1 indicates the order of the sample shots removed first, and the integer m2 is removed second. The order of sample shots is shown. Next, the nonlinear component B (m1,
The average value of N-1) and B (m2, N-2) is Q (m1,
As m2), the function T2 (m1, m2) is defined as follows.

[0056]

## EQU00006 ## Q (m1, m2) = {B (m1, N-1) + B (m1, N-2)} / 2, T2 (m1, m2) = Q (m1, m2) / D2 (m1, m2) After that, the procedure moves to step 114, where the group of sample shots removed when the value of the function T1 (m) is the largest (this is referred to as the M1 group) is calculated, and the integer m in the M1 group is calculated.
Value, that is, an integer value indicating the first removed sample shot. Specifically, in the case of FIG. 5C, when the value of the function T1 (m) is maximum, the M1 group is the sample shots SA ₁ , SA ₃ , SA ₁₀ , SA ₆ , SA ₆ , SA.
₄ , and the value of the integer m in the M1 group is 1.

Next, the group of sample shots removed when the value of the function T2 (m1, m2) becomes the maximum (this is referred to as the M2 group) is obtained, and the combination of the integers m1 and m2 in the M2 group is obtained. That is, an integer value indicating the first and second removed sample shots is obtained. Furthermore, the function T
A group of sample shots removed when the value of 2 (m1, m2) becomes the second largest (this is referred to as M2 ′ group) is obtained, and a combination of integers m1 and m2 in the M2 ′ group is obtained. Specifically, in the case of FIG. 5C, the function T2 (m
1, m2) is maximum, the M2 group is the sample shots SA ₁ , SA ₃ , SA ₁₀ , SA ₆ , SA, SA.
₄ , and the values of the integers m1 and m2 in the M2 group are 1 and 3, respectively.

However, if there are two jump shots,
The first and second sample shots of group M2 should be the same as the second and first sample shots of group M2 ', respectively. That is, the values of the integers m1 and m2 of the M2 group should be the same as the values of the integers m2 and m1 of the M2 ′ group, respectively. Therefore, when the combination of the integers m1 and m2 of the M2 group is different from the combination of the integers m2 and m1 of the M2 ′ group, the evaluation result is regarded as unreliable and the M2 group is not selected. The operation of not selecting the M2 group in this way is shown in step 116 described later. Then, the value of the function T1 (m) in the M1 group is set to the function T as follows.
_{As 1} , the functions T2 (m1, m2) and M2 ′ in the M2 group are
The average value with the function T2 (m1, m2) in the group is set as the function T ₂ .

[0059]

Equation 7] T ₁ = T1 (M1 group) = max (T1 (m) ), T 2 = {T2 (M2 group) + T2 (M2 'group)} / 2 = {max ( T2 (m1, m2)) + Next (T2 (m1, m2))} / 2 where max (T1 (m)) is the function T1 (m) (m = 1 to 1)
N), the function that finds the maximum value, max (T2 (m1, m
2)) is the function T2 (m1, m2) (m1, m2 = 1 to
N; m1 ≠ m2), the function that finds the maximum value, next (T
2 (m1, m2) is a function for obtaining the second largest value in the function T2 (m1, m2).

The functions T ₁ and T defined as above
₂ is a comparison function when the m-th sample shot is first removed and the sample shots are sequentially removed. In the subsequent step 115, another set of comparison functions S ₁ and S ₂ is obtained. These comparison functions S ₁ , S
₂ is a function indicating how much the comparison functions T ₁ and T ₂ obtained when the M1 group and the M2 group are selected are larger than when the other sample shots are selected, and are represented by the following expressions. However, the sum symbol Σ in the following formulas indicates a sum operation from 1 to N for the integer m or m1. Further, in step 115 of FIG. 1, the functions S ₁ 'and S ₂ ' are introduced, but the calculation results are the same.

[0061]

Equation 8] S ₁ = D1 (M1 group) / {(ΣD1 (m) -D1 (M1 group)) / (N-1) }, S 2 = D2 (M2 group) / {(ΣD2 (m1, m2 ) -Q (M2 group) · 2) / (N−2)} The comparison functions T ₁ , T ₂ , obtained as described above,
In step 116, it is determined whether or not there is a jump shot using S ₁ and S ₂ and the function R of the nonlinear component obtained in step 103. The following logical expression is used as the determination method.

T ₁ > 5 and S ₁ > 2 and T ₁
When> T ₂ is satisfied, it is determined that there is one jump shot, and the M1 group is selected. This is due to the nonlinear component B in the sample shot removed first from (Equation 4).
(M, N-1) with respect to time is greater than 5 times the average value D1 (m), and (8) function T ₁ is from the M1 group comparison, another sample shots selected 2 The comparison function T _{1 of the} M1 group is larger than double and the comparison function T _{2 of the} M2 group is
It means greater.

T ₂ > 5 and S ₂ > 2 and T ₂
When> T ₁ is satisfied, it is determined that there are two jump shots, and the M2 group is selected. However, step 114
As described above, the combination of m1 and m2 of the M2 group and M
When the combination of m2 and m1 of the 2'group is different, M
No choice is made between the two groups. The same applies to the following. When T ₁ > 2 and S ₁ > 2 and R> 0.07 are satisfied, it is determined that there is one jump shot,
Select group M1.

T ₂ > 2 and S ₂ > 2 and R>
When 0.07 is satisfied, it is determined that there are two jump shots, and the M2 group is selected. And above ~
Otherwise, it is judged that there is no jump shot. That is,
In step 117, the number of jump shots is 0 when the M1 group and the M2 group are not selected, and the number of jump shots is 1 when the M1 group is selected (sample shot determined by the integer m of the M1 group). When the M2 group is selected, there are two jump shots (an integer m of the M2 group).
1 and m2, the selected jump shots are removed.

After that, the process proceeds to step 118 and E is performed using the alignment data of the remaining sample shots.
GA calculation is performed to determine the values of the six coordinate conversion parameters of (Equation 1). After that, 6 obtained in this way
The coordinate conversion parameters and the design arrangement coordinates of each shot area ES _i (i = 1 to M) on the wafer 4 in FIG. 5A are substituted into the right side of (Equation 1) to obtain each shot area. ES _i
Find the calculated array coordinates of. Then, based on the calculated array coordinates, the center of each shot area ES _i is sequentially set to the exposure center of the projection optical system 3 in FIG. 3, and the pattern image of the reticle 2 is exposed. Thereby, the influence of the jump shot is reduced, and the pattern image of the reticle 2 is exposed with high overlay accuracy.

In this case, in this embodiment, step 105
As shown in, when the alignment data of the m-th sample shot is removed and the EGA calculation is performed using the alignment data of the n-piece sample shots, when the m-th sample shot is a jump shot, the remaining data is Since there are many accurate data, it means that the coordinate conversion parameters are accurately calculated. Therefore, in the next step 106, the non-linear error component of the alignment data is calculated again including the m-th sample shot.
It is possible to accurately determine how large the non-linear error component of the jump shot is.

In step 112, the nonlinear component B
Since the average value D1 (m) of (m, n) is calculated and the nonlinear component B (m, N-1) is divided by this average value to obtain the function T1 (m), the function to be compared The reliability of T1 (m) is high, and a jump shot can be stably found. Further, paying attention to the fact that the number of jump shots is at most one or two, as shown in steps 112 and 113, the function to be compared is T
Since 1 (m) and T2 (m1, m2) are divided and it is determined whether there are 1 or 2 jump shots, it is 2
It is not difficult to find a jump shot when there are two jump shots.

Further, as a method for judging the number of jump shots, as shown in step 116, the comparison functions S ₁ , S
_Since the relative comparison and the absolute value comparison are performed using ₂ , T ₁ and T ₂ , the reliability in specifying the jump shot is increased. In this case, it performs the example simulation with respect to the absolute value, may be set most detection rate high value (2 for 5, S _1, S ₂ for T _1, T ₂ as an example in the Oyobi step 116). In addition, when the M2 group that maximizes the function T2 (m1, m2) is obtained in step 114, the function T2 (m1,
m2) becomes the maximum value, the m2th and m1
Function T2 (m for removing the th sample shot
2, m1) does not have the second largest value, M
Since the second group is not selected, deterioration of accuracy due to erroneous detection is prevented.

Further, when the function R of the nonlinear component obtained in step 103 is small, the accuracy of alignment is deteriorated by removing the jump shots. Therefore, in step 116 and, the function R has a predetermined threshold value (step 1
In No. 16, as an example, when 0.07) or less, it is determined that there is no jump shot. Therefore, it is possible to prevent the accuracy from deteriorating when the function R of the nonlinear component is small.

Next, a second embodiment of the alignment method (alignment method) of the present invention will be described with reference to the flowchart of FIG. Also in this example, the projection exposure apparatus of FIG. 3 is used, and the wafer 4 of FIG. The operation of steps 101 to 116 shown in FIG. 2 of the present example is the same as the operation of steps 101 to 116 of the first embodiment shown in FIG. That is, also in the second embodiment, the comparison functions T ₁ , T ₂ , S ₁ , S in step 116 of FIG.
₂ and the function R of the nonlinear component, no group is selected when there is no jump shot, and the M1 group is selected when there is one jump shot.
When there are jumping shots, the M2 group is selected.

After that, the operation shifts to step 121, and the alignment data of the sample shot judged as the jump shot is weighted. Here, as an example, the weight is set to twice the reciprocal of the comparison functions T ₁ and T ₂ expressed by (Equation 7). That is, the weight assigned to each of the N sample shots SA _i (i = 1 to N) selected on the wafer 4 in FIG. 5A (N = 10 in FIG. 5A) is P (i ). Then, when there is one jump shot, the jump shot is regarded as the m-th sample shot, and the weight P (i) is set as follows.

[0072]

## EQU9 ## P (m) = 2 / T ₁ , P (i) = 1 (i ≠ m) In this case, if there is a jump shot, step 116
Since the value of the comparison function T ₁ is larger than 2, the value of the weight P (m) given to the jump shot is smaller than 1.

Next, when there are two jump shots, the weight P (i) is set as follows assuming that the jump shots are the m1th and m2th sample shots.

[0074]

[Equation 10] P (m1) = 2 / T ₂ , P (m2) = 2 / T ₂ , P (i) = 1 (i ≠ m1, m2) Also in this case, if a jump shot exists, step 11
Since the value of the comparison function T ₂ is larger than ₂ from 6, the value of the weights P (m1) and P (m2) given to the jump shot is 1
It gets smaller.

[0075] Then, jump sequence coordinates (x _i, y _i) in the design of shots including the sample shots SA _i (number 1) right to assign to the arrangement coordinates of the calculated resulting in (X _i,
Y _i ), the sum of the values obtained by multiplying the square of the absolute value of the alignment error vector obtained by subtracting the actually measured array coordinates (XM _i , YM _i ) by the square of the weight P (i). Is a residual error component as follows.

[0076]

[Equation 11]

Then, the values of the six conversion parameters of (Equation 1) are determined so that the residual error component of (Equation 11) takes the minimum value. This is called "weighted EGA calculation". This is because for every sample shot SA _i , all the terms of the determinant on the right-hand side of (Equation 1) are multiplied by the weight P (i) to calculate the calculated array coordinates, and the residual error component of (Equation 2) is calculated. It is equivalent to setting the value of the conversion parameter so as to minimize it.

After that, the routine proceeds to step 122, where the six coordinate conversion parameters thus obtained and the designed array coordinates of each shot area ES _i (i = 1 to M) on the wafer 4 are set. Substituting into the right side of (Equation 1), the calculated array coordinates of each shot area ES _i are obtained. Then, based on the calculated array coordinates, each shot area ES _i is positioned and the pattern image of the reticle 2 is exposed.

As described above, in the present embodiment, the detected jump shot is not removed, but a predetermined weight is given to the detected jump shot according to the size of the comparison functions T ₁ , T _2, etc. It is given and the conversion parameter is calculated. Therefore, the stability of the finally obtained array coordinates of the shot areas is increased. It should be noted that the present invention is not limited to the above-described two embodiments, and when the number of jump shots is 0 to 2, the position of the jump shot can be determined by performing comparison using predetermined two or more comparison functions (parameters). , And all of the methods for accurately recognizing the number. Further, the above-described embodiment is applied to the case where the present invention is applied to the case where alignment is performed by reducing the influence of a jump shot by the EGA method, but the present invention is a measurement system for examining the stage accuracy and overlay accuracy of the exposure apparatus. Therefore, it can be applied to the case where a jump in the measurement result occurs.

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

[0081]

According to the first alignment method of the present invention, since the sample area (jump shot) having the largest non-linear error component can be accurately specified, for example, by removing the jump shot, the EGA method can be used. When performing alignment by applying such a statistical processing method, it is possible to reduce the influence of the jump shot and set each processed region (shot region) of the substrate (wafer) to a predetermined exposure position with high accuracy. There are advantages.

Further, since the jump shots are specified by comparing the values T1 (m), which are normalized by the average value of the variations of the non-linear error components, the evaluation criteria for specifying the jump shots are automatically set. Since it is fixed, there is an advantage that the jump shot can be accurately specified. Furthermore, when the values T2 (m1, m2) obtained by standardizing the variations of the first two non-linear error components by the average value of the variations of the remaining non-linear error components are compared with each other, even if there are two jump shots, There is an advantage that these two jump shots can be specified.

The value T1 (m) standardized by the average value
And the value T2 (m1, m2) standardized by the average value are mutually compared, there is an advantage that it is possible to accurately determine whether there are one or two jump shots. Also, when calculating the array coordinates of the processing area excluding the jump shot,
In particular, when the non-linear error component of the jump shot is large, it is possible to perform accurate alignment as a whole.

On the other hand, when a small weight is given to a jump shot and the array coordinates of the region to be processed are calculated, especially when the nonlinear error component of the jump shot is not so large, the influence of the jump shot is reduced. In addition, it is possible to perform stable alignment while taking into consideration the result of the jump shot measurement to some extent. In this case, accurate weighting is performed by using a value corresponding to the reciprocal of the value T1 (m) standardized by the average value and the reciprocal of the value T2 (m1, m2) standardized by the average value as the weight. It can be performed.

Next, according to the second alignment method of the present invention, the variation of the non-linear error components of all the sample areas is obtained using the conversion parameters obtained by sequentially excluding one sample area, For example, the sample area that has been removed when obtaining the conversion parameter when this variation becomes the largest is taken as a jump shot. Therefore, the jump shot is accurately identified using the conversion parameter that is not affected by the value of the jump shot itself. After that, for example, the measurement data of the jump shot is lightly weighted, and the array coordinates of each processed region are calculated by statistical processing using all the measurement data, whereby the influence of the jump shot is reduced.

According to the third alignment method of the present invention, the sample area having a large non-linear error component is first identified as the jump area (jump shot). After that, for example, the measurement data of the jump shot is lightly weighted, and the array coordinates of each processed region are calculated by statistical processing using all the measurement data, whereby the influence of the jump shot is reduced.

[Brief description of drawings]

FIG. 1 is a flowchart showing a first embodiment of a positioning method (alignment method) according to the present invention.

FIG. 2 is a flowchart showing a second embodiment of the alignment method according to the present invention.

FIG. 3 is a configuration diagram showing a projection exposure apparatus to which the alignment method of the embodiment is applied.

FIG. 4A is a plan view showing an arrangement example of sample shots on a wafer to be exposed in the embodiment, and FIG. 4B is an explanatory diagram of a wafer mark detecting method.

FIG. 5 is a diagram showing an example of an array of sample shots including jump shots in an example.

FIG. 6 is an explanatory diagram showing an example of an alignment result using a conventional sample shot.

7 is a diagram showing a vector of a linear error in the sample shot of FIG.

FIG. 8 is an explanatory diagram showing an example of an alignment result using a sample shot including a conventional jump shot.

9 is a diagram showing a vector of a linear error in the sample shot of FIG.

[Explanation of symbols]

2 reticle 3 alignment system 18 alignment signal processing system of the alignment system 14 imaging signal processing system 15 TTL scheme of the projection optical system 4 wafer 6 wafer stage 8 laser interferometer 9 main control system 11 off-axis type ES ₁ ~ES _M shot areas SA ₁ ~SA _N sample shot Mx _i, My _i wafer mark

Claims (8)

[Claims] 1. An array coordinate on a predetermined coordinate system that defines a moving position of the substrate of a plurality of processing regions arrayed on the substrate according to a designed array coordinate is obtained, and the obtained array coordinate is set to the obtained array coordinate. In the method of aligning each of the plurality of processed regions with corresponding processing positions based on the above, N preselected sample regions (N is an integer of 6 or more) of the plurality of processed regions are provided. A first step of measuring the coordinate position on the predetermined coordinate system; and the m-th (from the coordinate position data of the n (n is an integer of the initial value N) sample areas measured in the first step. The non-linear error component of each coordinate position data including the m-th sample region is calculated using the result of statistically processing the (n-1) coordinate position data excluding the sample region of m) , And the n
A second step of obtaining the non-linear error component variations B (m, n-1); and (n-2) sample areas excluding the sample area having the largest non-linear error component obtained in the second step. And a second step until the sample area left in the third step reaches a predetermined lower limit value N _min .
Repeating the step and the third step to obtain the variation B (m, n-1) of the non-linear error component, respectively; and increasing the value of the integer m by 1 from 1 to N, respectively, the second step. To the fourth step are repeated to obtain the variation B (m, n-1) of the nonlinear error component, and the variation B (m in the range in which the variable (n-1) changes from (N-1) to _Nmin. , N−1) is the average value of the variation B
Fifth step of obtaining a value T1 (m) by normalizing (m, N-1)
Steps; N values T1 (m) obtained in the fifth step
A sixth step of detecting a sample area having a large non-linear component of the measurement result by comparing the above; and statistically processing the measured coordinate position data of the N sample areas including the sample area detected in the sixth step. A seventh step of calculating array coordinates of the plurality of processed regions on the predetermined coordinate system;
An alignment method comprising: 2. The alignment method according to claim 1, wherein in the fifth step, the value of the integer m is 1 to N for the variation B (m, n−1) of the nonlinear error components.
Variable (n-1) increases from (N-2) to N
A value T2 (m1, m2) obtained by normalizing the sum of B (m1, N-1) and B (m2, N-2) with the average value of the variation B (m, n-1) in the range changing to _min. (Integers m1 and m
2 indicates the order of the sample areas removed at this time), and in the sixth step, the N values T2 (m1, m2) obtained in the fifth step are compared to obtain a nonlinear An alignment method characterized by detecting a sample area having a large error component. 3. The alignment method according to claim 2, wherein in the sixth step, the N values T1 (m) and the N values T2 (m1, m2) are compared. A registration method characterized by detecting a sample area having a large non-linear error component. 4. The alignment method according to claim 1, 2, or 3, wherein in the seventh step, the remaining sample excluding the sample region detected as having a large nonlinear error component in the sixth step is excluded. A positioning method characterized by statistically processing coordinate position data measured in a region to calculate array coordinates of the plurality of regions to be processed on the predetermined coordinate system. 5. The alignment method according to claim 1, 2, or 3, wherein in the seventh step, a weight of the sample area detected as a large non-linear error component in the sixth step is reduced. In addition, the measured coordinate position data of the N sample areas are respectively weighted and statistically processed to calculate array coordinates of the plurality of processed areas on the predetermined coordinate system. And the alignment method. 6. The alignment method according to claim 5, wherein the N values T1 (m) are assigned as weights to the coordinate position data measured on the N sample areas, respectively.
Alternatively, a method according to the present invention is characterized in that a value corresponding to an inverse number of the N values T2 (m1, m2) is used. 7. Arrangement coordinates on a predetermined coordinate system that define the movement positions of the substrate of a plurality of processing regions arranged on the substrate according to the designed arrangement coordinates are obtained, and the obtained arrangement coordinates are set to the obtained arrangement coordinates. In the method of aligning each of the plurality of processed regions with corresponding processing positions based on the above, N preselected sample regions (N is an integer of 6 or more) of the plurality of processed regions are provided. A first step of measuring the coordinate position on the predetermined coordinate system; and the m-th (m is an integer of initial value 1) coordinate position data of the N sample areas measured in the first step. The sample area was excluded (N-
1) Statistical processing of coordinate position data is performed to obtain a conversion parameter from the designed array coordinate to the array coordinate on the predetermined coordinate system, and the obtained converted parameter and the designed array coordinate are used. The array coordinates of the N sample areas on the predetermined coordinate system are calculated, and the non-linear error component variation B ′ of the calculated N array coordinates is calculated.
A second step of obtaining (m, N-1); and the second step is repeated while increasing the value of the integer m by 1 to N, and the variation B '(m, N-
1) a third step; determining the second step and the third step
A third step of detecting a sample region having a large non-linear component of the measurement result by comparing the variations B ′ (m, N−1) of the N non-linear error components obtained in the step; And a fourth step of statistically processing the measured coordinate position data of the N sample areas including the sample area to calculate array coordinates of the plurality of processed areas on the predetermined coordinate system. A positioning method characterized by the above. 8. An array coordinate on a predetermined coordinate system that defines a moving position of the substrate of a plurality of processed regions arrayed on the substrate according to a designed array coordinate is obtained, and the obtained array coordinate is set to the obtained array coordinate. In the method of aligning each of the plurality of processed regions with corresponding processing positions based on the above, N preselected sample regions (N is an integer of 6 or more) of the plurality of processed regions are provided. A first step of measuring the coordinate position on the predetermined coordinate system, and processing the coordinate position data of the N sample areas measured in the first step,
A second step of determining a sample area having a large non-linear error component as a jump area; and weighting each of the N coordinate position data measured in the first step so as to reduce the jump area, And a third step of statistically processing the N coordinate position data to calculate array coordinates of the plurality of processed regions on the predetermined coordinate system.