JPH10185541A - Method for measuring accuracy of arrangement, photomask and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure the accuracy of arrangement of a transferred pattern while separating the accuracy of an aligner itself from other variation components in the lithography technology being employed in the fabrication of semiconductor device. SOLUTION: Arrangement accuracy of an aligner is calculated based on the position of first measurement patterns 14a-14h formed by exposure before exposure of a device pattern or the position of second measurement patterns 16a-16h formed by exposure after exposure of the device pattern. Subsequently, fluctuation of arrangement accuracy is calculated, at the time of exposing the device pattern, based on the position of first measurement patterns 14a-14h, the position of second measurement patterns 16a-16h and the arrangement accuracy of the aligner.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lithography technique used for manufacturing a semiconductor device and the like, and more particularly, to a photomask having a measurement pattern capable of measuring the arrangement accuracy of a transferred pattern with high accuracy, a semiconductor device, and a photomask. The present invention relates to an arrangement accuracy measuring method for measuring a measurement pattern.

[0002]

2. Description of the Related Art With the recent increase in the scale and integration of semiconductor devices, it has become important to form fine patterns with good reproducibility and high accuracy. An exposure method that scans the entire surface with an electron beam, a focused ion beam, X-rays, or the like and exposes the entire surface of the substrate requires a predetermined time corresponding to a device pattern from the start of exposure to the end of exposure. In some cases, the positional relationship between patterns immediately after the start of exposure and immediately before the end of exposure may be shifted due to thermal drift or the like.

For this reason, in order to form a pattern with good reproducibility, it is essential to control the arrangement accuracy of the exposed pattern. Conventionally, the arrangement accuracy of the pattern has been measured using the following measuring means. Was. First, a pattern serving as a main scale of a vernier pattern is exposed beforehand outside the region where the device pattern is exposed.

Next, a predetermined device pattern is exposed. Subsequently, the vernier pattern vernier is exposed at a position overlapping the main vernier pattern. Thereafter, the substrate is processed, and the deviation between the main scale and the vernier scale of the vernier pattern is read. By reading the vernier in this way, it is possible to measure the deviation of the arrangement accuracy before and after a series of exposure processes.

In addition, instead of the vernier pattern, an arbitrary measurement pattern is arranged on the outer periphery of the device pattern, and the interval between these patterns is measured using an electron microscope.

[0006]

However, in the above conventional arrangement accuracy measuring method using a vernier pattern,
Since the deviation amount of the vernier was read by human visual inspection, the measurement error was very large. Further, in the above-described conventional arrangement accuracy measuring method for measuring the interval between the measurement patterns, the orthogonality of the coordinates and the shrinkage component can be measured, but the information indicates the accuracy when the measurement pattern is exposed. However, the exposure accuracy of the device pattern could not be managed.

Further, in any of the above methods, it cannot be determined whether the cause of the displacement is the accuracy of the exposure apparatus itself or a fluctuation component due to thermal drift or the like. A way was desired.
An object of the present invention is to provide an arrangement accuracy measuring method for accurately measuring the arrangement accuracy of a transferred pattern while separating the accuracy of the exposure apparatus itself from other fluctuation components.

Another object of the present invention is to provide a photomask and a semiconductor device having a measurement pattern suitable for accurately measuring placement accuracy.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide an arrangement accuracy measuring method for measuring the arrangement accuracy of a device pattern formed on a substrate, the method comprising the steps of: Calculating the arrangement accuracy of the exposure apparatus based on the position of the measurement pattern or the position of the second measurement pattern formed by exposing after exposure of the device pattern, and determining the position of the first measurement pattern and the second measurement This is achieved by a placement accuracy measuring method, wherein a variation amount of the placement accuracy during the device pattern exposure is calculated based on a pattern position and the placement accuracy of the exposure apparatus. By measuring the placement accuracy of the device pattern in this way, the placement accuracy of the transferred pattern can be accurately measured while separating the accuracy of the exposure apparatus itself from other variable components.

In the above arrangement accuracy measuring method,
The first measurement pattern or the second measurement pattern has two measurement patterns arranged so as to have a predetermined interval, and the arrangement accuracy of the exposure apparatus is equal to a distance between the two measurement patterns. It is desirable to calculate by the deviation from the predetermined interval. Further, in the above-described arrangement accuracy measuring method, the amount of change in the arrangement accuracy at the time of the device pattern exposure is determined from a deviation amount of an arrangement distance between the first measurement pattern and the second measurement pattern from an ideal value. It is desirable to calculate by reducing the arrangement accuracy of the exposure apparatus.

In the above arrangement accuracy measuring method,
The first measurement pattern or the second measurement pattern includes a measurement pattern arranged along a first direction, and a measurement pattern arranged along a second direction orthogonal to the first direction. It is preferable to calculate the placement accuracy of the device pattern along the first direction and the placement accuracy of the device pattern along the second direction. By arranging the measurement pattern in this way, it is possible to measure the arrangement accuracy of the transferred pattern in the X direction and the Y direction on the substrate while separating the accuracy of the exposure apparatus itself and other fluctuation components. it can.

[0012] Further, the object is to provide a photomask in which a device pattern is formed on a transparent substrate, wherein the first measurement pattern and the second measurement pattern used in the arrangement accuracy measuring method are formed on the transparent substrate. This is also attained by a photomask characterized in that is formed. By configuring the photomask in this manner, the exposure accuracy of the pattern can be accurately known, so that the device pattern can be transferred onto the transparent substrate with good reproducibility.

[0013] Further, the above object is to provide a semiconductor device having a device pattern formed on a semiconductor substrate, wherein the first device used in the above arrangement accuracy measuring method is provided on the semiconductor substrate.
This is also achieved by a semiconductor device in which the measurement pattern described above and the second measurement pattern are formed. By configuring the semiconductor device in this way, the exposure accuracy of the pattern can be accurately known, so that the device pattern can be transferred onto the semiconductor substrate with good reproducibility.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a photomask, a semiconductor device, and a placement accuracy measuring method according to an embodiment of the present invention.
This will be described with reference to FIGS. FIG. 1 is a schematic view showing the structure of a photomask according to the present embodiment, FIGS. 2 and 3 are diagrams for explaining the arrangement accuracy measuring method according to the present embodiment, and FIG. 4 shows the structure of another photomask according to the present embodiment. It is a schematic diagram.

In the present embodiment, the present invention will be described by taking as an example a case where a device pattern is exposed on a photomask dry plate using an electron beam exposure method. First, the photomask according to the present embodiment will be explained with reference to FIG. A device pattern 12 for exposing a predetermined device pattern to a wafer is formed at the center of the glass substrate 10. In FIG. 1, the device pattern 12 is represented by a square area, but in practice, a fine pattern corresponding to, for example, one chip of the semiconductor device is drawn therein.

Substrate 1 provided with device pattern 12
Measurement patterns 14a to 14h and 16a to 16h for measuring the placement accuracy are provided in the peripheral portion of 0.
Four measurement patterns are provided at each of the four corners of the substrate 10, and one measurement pattern is a cross pattern having a width of about 10 μm. For convenience, in FIG. 1, the measurement patterns 14a to 14h are represented by solid lines, and the measurement patterns 16a to 16h are represented by dotted lines.

Here, the measurement patterns 14a to 14h are patterns exposed before exposing the device pattern 12, and the measurement patterns 16a to 16h are patterns exposed after exposing the device pattern 12. During the exposure of the measurement patterns 14a to 16h and the measurement patterns 16a to 16h, a time shift occurs in which the device pattern 12 is exposed.

In the photomask according to the present embodiment shown in FIG. 1, the upper right corner and the upper left corner of the measurement pattern include only the pattern located at the upper left of the measurement pattern 16a or 16b, and the other patterns are the measurement patterns 14a to 14a.
4f. As for the measurement patterns at the lower right corner and the lower left corner, only the pattern located at the upper left is constituted by the measurement patterns 14g or 14h, and the other patterns are constituted by the measurement patterns 16c to 16h.

In these measurement patterns, the measurement pattern 16a and the measurement pattern 14d have a distance of 113 mm, the measurement pattern 14a and the measurement pattern 16b have a distance of 110 mm, and the measurement pattern 16a and the measurement pattern 16d Have a distance of 86.5 mm, and the measurement pattern 14b and the measurement pattern 14g are regularly arranged on the 5-inch square glass substrate 10 so as to have a distance of 83.5 mm.

Next, the arrangement accuracy measuring method according to the present embodiment will be described with reference to FIGS. First, Figure 1
5 shows a method for measuring the pattern placement accuracy along the upper side and the right side of the photomask shown in FIG. First, the deviation of the placement accuracy due to the performance of the exposure apparatus itself is measured.

It is considered that the deviation of the arrangement accuracy due to the exposure apparatus itself is substantially constant throughout a series of exposure steps. Therefore, in order to measure the arrangement accuracy of the exposure apparatus itself, the measurement can be performed by measuring the distance between two measurement patterns having a short exposure time interval. For example, in the photomask shown in FIG. 1, it is possible to measure the placement accuracy in the X direction by measuring the change in the distance between the measurement pattern 14b and the measurement pattern 14f and the distance between the measurement pattern 16d and the measurement pattern 16h. By measuring the change in the distance between the measurement pattern 16a and the measurement pattern 16d and the distance between the measurement pattern 16b and the measurement pattern 16g, the arrangement accuracy in the Y direction can be measured.

Here, when focusing on the measurement pattern 16d and the measurement pattern 16h, the measurement pattern 16d is -0.19 μm in the X direction and 0.0 in the Y direction from the ideal coordinates.
Assume that the measurement pattern 16h is shifted by −0.14 μm in the X direction and 0.03 μm in the Y direction from the ideal coordinates (see FIG. 2). These measurement patterns 16
Since the length between d and 16h is not considered to be affected by thermal drift or the like during exposure, the deviation between the distance between these measurement patterns and the ideal value reflects the accuracy of the exposure apparatus itself. It is considered something.

Therefore, the measurement patterns 16d, 16h
In consideration of the above, the displacement in the X direction due to the performance of the exposure apparatus itself can be estimated as −0.14 μm − (− 0.19 μm) = 0.05 μm (1) Similarly, a change in the length in the Y direction is considered.

Here, when focusing on the measurement pattern 16a and the measurement pattern 16d, the measurement pattern 16a is shifted by -0.08 μm from the ideal coordinates only in the X direction,
The measurement pattern 16d is -0.1 in the X direction from the ideal coordinates.
9 μm and 0.02 μm in the Y direction.
reference). The length of these measurement patterns 16a and 16d is
As in the case of the X direction, it is considered that there is no influence from thermal drift during exposure or the like. Therefore, the deviation between the distance between these measurement patterns and the ideal value reflects the accuracy of the exposure apparatus itself, and the displacement in the Y direction due to the performance of the exposure apparatus itself is 0.02 μm−0 μm = 0.02 μm ... (2) can be estimated.

Next, a variation component of the placement accuracy due to a thermal drift or the like is calculated. Variation components of the placement accuracy due to thermal drift or the like include any of the measurement patterns 14a to 14h exposed before exposing the device pattern and the measurement patterns 16a to 1h exposed after exposing the device pattern.
This is done by measuring the distance to any of 6h.
By using the distance between these two points and the displacement due to the performance of the exposure apparatus, it is possible to separate the fluctuation component of the placement accuracy due to thermal drift or the like from the entire displacement.

First, the measurement patterns arranged at substantially the same intervals as the measurement patterns 16d and 16h in which the displacement caused by the performance of the exposure apparatus itself is measured, and which are exposed at different stages from each other, are selected. For example,
The measurement pattern 16a and the measurement pattern 14d are selected.
The reason why the measurement patterns arranged at intervals substantially equal to the measurement patterns 16d and 16h in which the displacement caused by the performance of the exposure apparatus itself is measured is selected in order to accurately estimate the displacement caused by this distance. However, in a normal photomask, the measurement patterns 14a to 14h and 16a arranged at one corner with respect to the length of one side of the glass substrate 10
Since the arrangement intervals of ｈh are extremely narrow, it is possible to estimate the arrangement deviation without strictly selecting measurement patterns at equal intervals.

Here, assuming that the measurement pattern 14d is shifted by +0.08 μm from the ideal coordinates only in the X direction and the measurement pattern 16a is shifted by −0.08 μm from the ideal coordinates in the X direction (see FIG. 2). Considering the measurement pattern 16a and the measurement pattern 14d, the deviation of the distance in the X direction from the ideal value is 0.08 μm − (− 0.08 μm) = 0.16 μm (3)

Here, 0.05 μm obtained by the equation (1)
Represents the change in the length in the X direction due to the performance of the exposure apparatus itself, and it is considered that the same change occurs when the measurement pattern 14d is exposed. Therefore, it is considered that 0.16 μm obtained by the equation (3) includes a variation due to the performance of the exposure apparatus itself and a variation due to a thermal drift or the like generated at the time of device pattern exposure. . That is, it can be seen that the fluctuation component in the X direction due to thermal drift or the like is 0.16 μm−0.05 μm = 0.11 μm (4).

Similarly, the measurement pattern 14d is shifted by +0.08 μm from the ideal coordinates only in the X direction, and the measurement pattern 16h is shifted by −0.14 μm from the ideal coordinates in the X direction.
Assuming that the displacement is 0.03 μm in the Y direction, the variation component in the Y direction is 0.03 μm−0.02 μm = 0 by using the result of Expression (2) in consideration of the measurement pattern 16h and the measurement pattern 14d. .01 μm (5)

By measuring the coordinates of each measurement pattern in this manner, the pattern placement accuracy along the upper side and the right side can be measured. Next, the pattern placement accuracy along the lower side and the left side is measured in the same manner as the method of measuring the pattern placement accuracy along the upper side and the right side. First, the deviation of the placement accuracy due to the performance of the exposure apparatus itself is measured.

For example, in the photomask shown in FIG. 1, the arrangement accuracy in the X direction is measured by measuring the distance between the measurement pattern 14c and the measurement pattern 14e and the change in the distance between the measurement pattern 16e and the measurement pattern 16g. Measurement pattern 14b and measurement pattern 14
By measuring the distance between the measurement pattern 14g and the distance between the measurement pattern 14e and the measurement pattern 14h, the arrangement accuracy in the Y direction can be measured.

Here, when focusing on the measurement pattern 14c and the measurement pattern 14e, the measurement pattern 14c is shifted by -0.03 μm from the ideal coordinates only in the X direction.
The measurement pattern 14e is set at 0. 1 only in the X direction from the ideal coordinates.
It is assumed that it is shifted by 03 μm (see FIG. 3). Then
Similarly to the equation (1), the displacement in the X direction due to the performance of the exposure apparatus itself can be estimated as 0.03 μm − (− 0.03 μm) = 0.06 μm (6).

Similarly, the measurement pattern 14e is shifted by 0.03 μm from the ideal coordinates only in the X direction, and the measurement pattern 14h is shifted by −0.16 μm from the ideal coordinates in the X direction.
Assuming that the measurement pattern 14e and the measurement pattern 16h are displaced by 0.03 μm in the direction (see FIG. 3), the displacement in the Y direction due to the performance of the exposure apparatus itself is 0.03 μm−0 μm = 0.03 μm. ... (7) can be estimated.

Next, a variation component of the placement accuracy due to a thermal drift or the like is calculated. First, the measurement patterns arranged at substantially the same intervals as the measurement patterns 14c and 14e in which the displacement caused by the performance of the exposure apparatus itself is measured, and which are exposed at different stages from each other, are selected.
For example, the measurement pattern 16c and the measurement pattern 14h are selected.

Here, the measurement pattern 14h is shifted by -0.16 μm in the X direction and 0.03 μm in the Y direction from the ideal coordinates, and the measurement pattern 16c is shifted by −0.18 μm in the X direction from the ideal coordinates and in the Y direction. If the measurement pattern 14h and the measurement pattern 16c are considered, the deviation from the ideal value of the distance in the X direction is −0.16 μm − (− 0.18 μm) = 0. .02 μm (8)

Here, 0.06 μm obtained by the equation (6) is used.
Represents the change in the length in the X direction due to the performance of the exposure apparatus itself, and it is considered that a similar change occurs when the measurement pattern 16c is exposed. Therefore, it is considered that 0.02 μm obtained by the equation (8) includes a variation due to the performance of the exposure apparatus itself and a variation due to a thermal drift or the like generated at the time of device pattern exposure. . In other words, the amount of change in the X direction due to thermal drift or the like is 0.02 μm−0.06 μm = −0.04 μm (9)

Similarly, the measurement pattern 14c is shifted from the ideal coordinates only in the X direction by -0.03 μm, and the measurement pattern 16c is shifted from the ideal coordinates by −0.18 μm in the X direction.
Assuming that the displacement is 0.04 μm in the Y direction, the variation component in the Y direction is 0.04 μm−0.03 μm = 0 by using the result of Expression (7) in consideration of the measurement pattern 14c and the measurement pattern 16c. .01 μm (10)

By measuring the coordinates of each measurement pattern in this manner, the pattern placement accuracy on the lower side and the left side can be measured. Table 1 summarizes the results obtained by the above series of measurement methods.

[0039]

[Table 1] As shown in Table 1, in the direction along each side of the device pattern, the arrangement accuracy of the exposure apparatus and the fluctuation component at the time of device pattern exposure can be measured separately. As described above, according to the present embodiment, the measurement pattern exposed before the exposure of the device pattern and the measurement pattern exposed after the exposure of the device pattern are provided, and the arrangement accuracy of the exposure apparatus itself is determined based on the measurement pattern exposed at the same stage. Is calculated, and the total arrangement accuracy is calculated from the measurement patterns exposed at different stages. Therefore, it is separately measured whether the cause of the arrangement deviation is the accuracy of the exposure apparatus itself or a fluctuation component due to thermal drift or the like. be able to.

In the above-described embodiment, an example in which four measurement patterns are provided at four corners is shown, but it is not always necessary to provide four measurement patterns. By providing at least two measurement patterns exposed at the same stage and one measurement pattern exposed at different stages, the same arrangement accuracy measurement as in the present embodiment can be performed. For example, as shown in FIG. 4, if two measurement patterns 18a and 18b exposed at the same stage are provided in a diagonally located area of the glass substrate 10, the performance of the exposure apparatus itself can be reduced from these measurement patterns 18a and 18b. The resulting changes in the lengths in the X and Y directions can be determined.

Further, one measurement pattern 20a exposed at different stages is provided in a region located at a diagonal different from the diagonal where the measurement patterns 18a and 18b are provided, and the measurement pattern 18a and the measurement pattern 20a or the measurement pattern 20a are provided. 1
In consideration of 8b and the measurement pattern 20a, if the shift amount due to the apparatus itself is used, it is also possible to obtain the fluctuation amount of the exposure accuracy along the left side or the lower side of the device pattern.

If the measurement pattern 20b is provided at the diagonal of the measurement pattern 20a, the variation of the exposure accuracy along the right side or the upper side of the device pattern can be obtained.
The measurement patterns 18a and 18b exposed at the same stage
It is not necessary to arrange along the direction or the Y direction,
As shown in FIG. 4, they can be arranged diagonally.

Further, in the above embodiment, the case where the measurement pattern is formed on the photomask dry plate by the electron beam exposure has been described, but the present invention can be similarly applied to the case where the electron beam is directly drawn on the semiconductor wafer. The arrangement accuracy measuring method according to the present invention can also be applied to an exposure method using a stepper. For example, a plurality of chips located at the peripheral edge of the semiconductor wafer are defined in advance as measurement chips, some of these chips are exposed in a step immediately after the start of exposure, and the other chips are exposed in a step immediately before the end of exposure. If exposure is performed and the coordinate deviation between these chips is measured after development, the placement accuracy between chips on the wafer surface can be measured even in an exposure method using a stepper.

The present invention is not limited to the electron beam exposure, and can be similarly applied to an exposure method using a focused ion beam or X-rays. In the above embodiment, the measurement patterns 14a to 14h and 16a to 16h are formed by the cross patterns, but these measurement patterns are not limited to the cross patterns. The pattern can be appropriately selected according to the characteristics of the electron microscope used for the length measurement.

[0045]

As described above, according to the present invention, there is provided an arrangement accuracy measuring method for measuring the arrangement accuracy of a device pattern formed on a substrate. The placement accuracy of the exposure apparatus is calculated based on the position of the measurement pattern or the position of the second measurement pattern formed by exposure after exposure of the device pattern, and
Based on the position of the measurement pattern, the position of the second measurement pattern, and the placement accuracy of the exposure apparatus, the placement accuracy of the device pattern is determined by a placement accuracy measurement method that calculates a variation amount of the placement accuracy during device pattern exposure. Since the measurement is performed, the arrangement accuracy of the transferred pattern can be accurately measured while separating the accuracy of the exposure apparatus itself from other variable components.

In the above arrangement accuracy measuring method, the first
The measurement pattern or the second measurement pattern has two measurement patterns arranged so as to have a predetermined interval,
The arrangement accuracy of the exposure apparatus can be calculated based on a deviation of a distance between two measurement patterns from a predetermined interval.
In the above arrangement accuracy measuring method, the amount of change in the arrangement accuracy at the time of exposing the device pattern is determined by calculating the difference between the arrangement distance between the first measurement pattern and the second measurement pattern from the ideal value by using the exposure apparatus. Can be calculated by reducing the arrangement accuracy of the.

In the above arrangement accuracy measuring method,
The first measurement pattern or the second measurement pattern has a measurement pattern arranged along a first direction and a measurement pattern arranged along a second direction orthogonal to the first direction. By calculating the placement accuracy of the device pattern along the first direction and the placement accuracy of the device pattern along the second direction, the accuracy of the exposure apparatus itself in each of the X and Y directions on the substrate is calculated. The arrangement accuracy of the transferred pattern can be measured while separating the and the other variable components.

In a photomask in which a device pattern is formed on a transparent substrate, the first measurement pattern and the second measurement pattern used in the above arrangement accuracy measuring method are formed on the transparent substrate.
By constructing a photomask on which the measurement pattern is formed, the exposure accuracy of the pattern can be accurately known, so that the device pattern can be transferred onto the transparent substrate with good reproducibility.

In a semiconductor device having a device pattern formed on a semiconductor substrate, the first measurement pattern and the second measurement pattern used in the above-described arrangement accuracy measuring method are formed on the semiconductor substrate. With this configuration, since the exposure accuracy of the pattern can be accurately known, the device pattern can be transferred onto the semiconductor substrate with good reproducibility.

[Brief description of the drawings]

FIG. 1 is a schematic view illustrating a structure of a photomask according to an embodiment of the present invention.

FIG. 2 is a diagram (part 1) for explaining a placement accuracy measuring method according to an embodiment of the present invention;

FIG. 3 is a diagram (part 2) illustrating a placement accuracy measuring method according to an embodiment of the present invention.

FIG. 4 is a schematic diagram showing a structure of a photomask according to a modification of one embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Glass substrate 12 ... Device pattern 14a-14h ... Measurement pattern (exposed before device pattern exposure) 16a-16h ... Measurement pattern (exposure after device pattern exposure) 18a, 18b ... Measurement pattern 20a, 20b ... Measurement pattern

Claims (6)

[Claims] 1. An arrangement accuracy measuring method for measuring the arrangement accuracy of a device pattern formed on a substrate, comprising:
Calculating the arrangement accuracy of the exposure apparatus based on the position of the measurement pattern or the position of the second measurement pattern formed by exposing after exposure of the device pattern, the position of the first measurement pattern and the position of the second Based on the position of the measurement pattern and the placement accuracy of the exposure apparatus,
A placement accuracy measuring method, wherein a variation amount of the placement accuracy at the time of the device pattern exposure is calculated. 2. The arrangement accuracy measuring method according to claim 1, wherein the first measurement pattern or the second measurement pattern has two measurement patterns arranged so as to have a predetermined interval. An arrangement accuracy measuring method, wherein the arrangement accuracy of the exposure apparatus is calculated based on a deviation of a distance between the two measurement patterns from the predetermined interval. 3. The arrangement accuracy measuring method according to claim 1, wherein the amount of change in the arrangement accuracy at the time of the device pattern exposure is a distance between the first measurement pattern and the second measurement pattern. A method for calculating the arrangement accuracy of the exposure apparatus by subtracting the arrangement accuracy of the exposure apparatus from the deviation amount from the ideal value. 4. The arrangement accuracy measuring method according to claim 1, wherein the first measurement pattern or the second measurement pattern is different from a measurement pattern arranged along a first direction. , A measurement pattern arranged along a second direction orthogonal to the first direction, an arrangement accuracy of the device pattern along the first direction, and a measurement pattern arranged along the second direction. An arrangement accuracy measuring method, wherein the arrangement accuracy of the device pattern is calculated. 5. A photomask in which a device pattern is formed on a transparent substrate, wherein the first measurement pattern and the first measurement pattern used in the placement accuracy measuring method according to claim 1 are formed on the transparent substrate. A photomask on which a second measurement pattern is formed. 6. A semiconductor device having a device pattern formed on a semiconductor substrate, wherein the first measurement pattern and the first measurement pattern used in the placement accuracy measuring method according to claim 1 are arranged on the semiconductor substrate. A semiconductor device having a second measurement pattern formed thereon.