JP2022021652A - Photomask - Google Patents

Abstract

To provide a photomask capable of reducing unevenness of exposure of an exposure apparatus.SOLUTION: A photomask of the invention includes, on a permeable substrate, a reference region and at least one permeability correction region adjacent to the reference region. The permeability correction region is extended over a full length of a photomask transfer region, and the permeability correction region and the reference region are different in light transmittance. Positions of the permeability correction region and the reference region, and a relative transmittance of a transmittance exposure apparatus with respect to the reference region are obtainable by measuring a cumulative exposure dose distribution.SELECTED DRAWING: Figure 2

Description

The present invention relates to a photomask.

Conventionally, in order to transfer a pattern to a large substrate such as a flat panel display (for example, one side is several tens of centimeters to one or two meters in size), a pattern is used by using a multi-scanning exposure apparatus equipped with a plurality of projection optical systems. A technique called so-called joint exposure or joint exposure, which exposes an optical system, is known. The mask and the substrate are moved (scanned) synchronously with respect to a plurality of irradiation optical systems, and the images projected through the plurality of projection optical systems are joined to enable a large area transfer.
In order to connect the transfer patterns between adjacent illumination regions, each illumination region has a shape inclined with respect to the scanning direction (for example, a trapezoidal shape or an arc shape), and the projection optical system adjacent to the scanning direction is used. Each illumination area is arranged so as to have a double exposure at the end of the formed projection area.

Japanese Unexamined Patent Publication No. 2016-24257 Japanese Unexamined Patent Publication No. 2013-238670

The integrated exposure amount in the area (connecting area) where the double exposure is performed in the projection area does not completely match the integrated exposure amount in the other areas, and exposure unevenness may occur in this area. When the exposure unevenness occurs on the substrate, for example, the transferred pattern size fluctuates, which increases the risk of adversely affecting the fine image of the display device.
In order to reduce exposure unevenness, Patent Document 1 discloses a method of adjusting the irradiation amount of an illumination region to be double-exposed with a filter, and Patent Document 2 discloses a method of adjusting the shape of an irradiation region. ing.
Both methods require a high degree of control of the optical system, and it may be difficult to improve the exposure unevenness only by adjusting the exposure apparatus. As the demand for the finish accuracy of the transfer pattern becomes stricter, it is required to further reduce the exposure unevenness.

An object of the present invention is to provide a photomask capable of reducing exposure unevenness.

The photomask according to the present invention is
The transmissive substrate has a reference region and at least one transmittance correction region adjacent to the reference region.
The transmittance correction region extends over the entire length of the transfer region and extends.
It is characterized in that the light transmittance of the transmittance correction region and the reference region are different.

Further, the photomask according to the present invention is
A plurality of the transmittance correction regions are provided, and the plurality of the transmittance correction regions extend in the same direction.

With such a photomask configuration, it is possible to reduce the exposure unevenness due to the minute fluctuation portion of the illuminance distribution of each illumination region arranged so as to be double exposure of the exposure apparatus by the transmittance of the photomask. ..

Further, the photomask according to the present invention is
A semi-transmissive film is formed in the region having a low transmittance among the transmittance correction region and the reference region.
The transmittance of the semi-permeable membrane is lower than the transmittance of the permeable substrate.

Further, the photomask according to the present invention is
The semi-transmissive film is partially formed, and the light transmittance is controlled by the occupancy rate of the semi-transmissive film.

Further, the photomask according to the present invention is
The photomask has a light-shielding pattern and has a light-shielding pattern.
The light-shielding pattern is characterized by including at least one of a laminated structure of a light-shielding film and an etching stopper film or a laminated structure of a light-shielding film and an etching stopper film and the semi-transmissive film.

Further, the photomask according to the present invention is
The photomask has a light-shielding pattern and has a light-shielding pattern.
The light-shielding pattern is characterized by having a laminated structure of the light-shielding film and the semi-transmissive film.

With such a photomask configuration, the transmittance can be controlled by the occupancy rate (coverage rate) of the semitransmissive film.
In addition, a pattern made of a light-shielding film can be formed on a photomask in which the transmittance is controlled and exposure unevenness is reduced, and dimensional fluctuation of the transfer pattern can be reduced.

Further, the photomask according to the present invention is
In the region of the transmittance correction region and the reference region where the transmittance is low, the transmissive substrate is partially covered with a light-shielding film, and the light transmittance is controlled by the occupancy of the light-shielding film. It is a feature.

With such a photomask configuration, the transmittance can be controlled by the light-shielding film. It can also contribute to the simplification of the photomask manufacturing process.

Further, the method for manufacturing a photomask according to the present invention is as follows.
The process of measuring the integrated exposure amount distribution of the exposure equipment and
From the integrated exposure amount distribution, a step of determining the positions of the reference region and the transmittance correction region of the photomask and calculating the correction value of the transmittance of the transmittance correction region relative to the reference region.
It is characterized by including a step of correcting the transmittance of the transmittance correction region relative to the reference region based on the correction value.

By adopting such a photomask manufacturing method, exposure unevenness is reduced according to the state of the exposure apparatus actually used, so that the optimum integrated exposure amount can be corrected.

According to the photomask according to the present invention, exposure unevenness can be reduced.
As a result, it can contribute to the improvement of the quality of the product manufactured by using the photomask.

FIG. 1 (a) is a perspective view showing an outline of the exposure apparatus 200, and FIG. 1 (b) is a graph schematically showing the time change of the intensity of the exposure light projected on the point on the substrate P. .. FIG. 2A is a plan view showing an arrangement example of the projection area projected on the substrate P, and FIG. 2B is a graph showing the integrated exposure amount of the substrate P by the projection area PR. FIG. 2C is a graph showing the distribution of the transmittance of the photomask 100 for correcting the non-uniformity of the integrated exposure amount in the overlapping projection region PAO, and FIG. 2D is an enlarged plan view of the photomask 100. be. FIG. 3A is a plan view of the photomask 100 in which a semi-transmissive region is formed in an overlapping illumination region for projecting the overlapping projection region PAO, and FIGS. 3B, 3C, and 3D are FIGS. It is an enlarged plan view of the area surrounded by the circle of (a). FIG. 4 is an enlarged plan view of the photomask 100 showing a method of adjusting the transmittance of the semi-transmissive region 2. FIG. 5 is a plan view of a photomask 100 having a transmission region 4, a semi-transmission region 2, and a predetermined pattern 5. FIG. 6 shows a cross-sectional view of a main manufacturing process of the photomask 100 according to the first embodiment. FIG. 7 shows a cross-sectional view of a main manufacturing process of the photomask 100 according to the first embodiment. FIG. 8 shows a cross-sectional view and a plan view of the main manufacturing process of the photomask 100 according to the second embodiment. FIG. 9 shows a cross-sectional view and a plan view of the main manufacturing process of the photomask 100 according to the second embodiment. 10 (a) is an enlarged plan view of the photomask 100 according to the third embodiment, and FIGS. 10 (b) and 10 (c) are cross-sectional views showing a main manufacturing process of the photomask 100. FIG. 11A is a graph showing the position dependence of the integrated exposure amount of the exposure amount exposed to the substrate P in the Y direction, and FIG. 11B is a non-uniformity of the integrated exposure amount in the overlapping projection region PAO. 11 (c) and 11 (d) are enlarged plan views and cross-sectional views of the photomask 100 according to the fifth embodiment, which are graphs showing the Y-direction distribution of the transmittance of the photomask 100 for compensating for the above. FIG. 12 is a plan view of the photomask 100 that reduces the exposure unevenness of the exposure apparatus 200. FIG. 13A is a perspective view showing an arrangement example of the optical detector 10 for measuring the intensity distribution of the exposure light of the substrate P, and FIG. 13B is a perspective view of the calibration photomask 100'. It is a figure. FIG. 14A is a plan view of a measurement photomask 100'' having a measurement pattern 12 composed of a linear pattern, and FIG. 14B is a measurement pattern 12 composed of rectangular hole patterns arranged in the Y direction. 14 (c) and 14 (d) are plan views of the measurement photomask 100 ″, which are enlarged plan views of the pattern of the photoresist film 13 formed on the substrate P.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, none of the following embodiments give a limiting interpretation in finding the gist of the present invention. Further, the same or the same kind of members may be designated by the same reference numerals and the description thereof may be omitted.

(Exposure device)
FIG. 1A is a perspective view showing an outline of the exposure apparatus 200. The exposure apparatus 200 has the configuration described below, and may be referred to as a "multi-scanning exposure apparatus" (or "multi-projection exposure apparatus").
The photomask 100 is held by a mask stage (not shown), and the substrate P to be exposed is held in parallel with the photomask 100 by a substrate stage (not shown). The photomask 100 and the substrate P can be synchronously moved in the same direction and at the same speed by the mask stage and the substrate stage, respectively.

Hereinafter, the moving direction of the photomask 100 and the substrate P is defined as the X direction, the direction perpendicular to the X direction is defined as the Y direction, and the phrase perpendicular to the X direction and the Y direction is defined as the Z direction. The Z direction is perpendicular to the surface of the photomask 100 (and the substrate P).
The mask stage and the substrate stage each have a moving mechanism, can move in the X direction, the Y direction, and the Z direction, and can rotate on a plane perpendicular to the Z direction. The mask stage and the substrate stage read the alignment marks provided on the photomask 100 and the substrate P, and can be aligned by the moving mechanism.

As disclosed in Patent Documents 1 and 2, in the exposure apparatus 200, the light emitted from the light source 201 is incident on the branch optical system 202 and is branched into a plurality of illumination optical systems 203 (2031 to 2037).

Each illumination optical system illuminates the illumination region IL (IL1 to IL7) on the photomask 100 with a uniform illuminance distribution. The illumination region IL has a shape (for example, a trapezoidal shape, an arc shape, etc.) inclined with respect to the scanning direction due to the aperture provided in each illumination optical system.
The illuminated areas IL1, IL3, IL5, IL7 and the illuminated areas IL2, IL4, IL6 are aligned in the Y direction at predetermined intervals. The illumination regions IL2, IL4, and IL6 are separated from the illumination regions IL1, IL3, IL5, and IL7 by a predetermined distance in the X direction. The illuminated areas IL1, IL3, IL5, IL7 and the illuminated areas IL2, IL4, IL6 are arranged in a staggered pattern (alternately) so as to partially overlap in the X direction.

The light irradiated to the illumination region IL (IL1 to IL7) of the photomask 100 passes through the photomask 100 having a predetermined pattern, and is projected onto the substrate P via a plurality of projection optical systems 204 (2041 to 2047). It is projected onto the area PR (PR1 to PR7). Each projection area PR (PR1 to PR7) corresponds to each illumination area IL (IL1 to IL7).
Light reflecting the pattern formed on the photomask 100 is projected on each projection region PR (PR1 to PR7), and a photosensitive substance (for example, a photoresist, a photosensitive resin, etc.) formed on the substrate P is projected. It is exposed by the light.
Since the photomask 100 and the substrate P move synchronously while light is projected in each projection region PR of the substrate P, the projected light is superposed and a large area of photosensitive material can be exposed.
The number of the illumination area IL and the projection area PR is not limited to the above, and can be appropriately set.

FIG. 1B is a graph schematically showing the time change of the intensity of the exposure light projected on the points Y1, Y2, and Y3 on the substrate P by the exposure apparatus 200. The vertical axis is the intensity of the exposure light (Dose), and the horizontal axis is the time. The points Y1, Y2, and Y3 are irradiated with the exposure light while crossing the projection regions PR1 and PR2.
The shape of the projection area PR shows an example of a shape in which two trapezoids are combined, but the shape is not limited thereto, and the shape of the projection area PR can be appropriately set.

Since the photomask 100 and the substrate P move in synchronization, the point Y1 on the substrate P crosses only the projection area PR1 and the point Y3 crosses only the projection area PR2, but the point Y2 crosses the projection area PR1 and the projection area PR2. Cross. The time that the point Y1 crosses the projection area PR1 is equal to the time that the point Y3 crosses the projection area PR2, but the time that the point Y2 crosses the projection area PR1 is shorter than the time that the point Y1 crosses the projection area PR1 and the point Y2 crosses the projection area PR1. The time across PR2 is shorter than the time it takes for point Y3 to cross projection region PR2. Ideally, if the sum of the time that the point Y2 crosses the projection area PR1 and the time that the point Y2 crosses the projection area PR2 is equal to the time that the point Y1 crosses the projection area PR1, the integrated exposure amount of each point Y1, Y2, Y3 is equal. However, as will be described later, the integrated exposure amount of the point Y2 does not necessarily match the integrated exposure amount of the points Y1 and Y3.

(Mask for exposure distribution correction)
FIG. 2A shows a plan view of an arrangement example of the projection region PR (PR1, PR2, PR3) projected on the substrate P.
As the photomask 100 and the substrate P move, the projection region PR relatively moves (scans) in the X direction shown in FIG. 2A, for example. The alternately arranged projection areas PR1 and PR3 and the projection area PR2 overlap each other in a part of the area PAO (referred to as "overlapping projection area PAO"), and the other areas PAS do not overlap each other and are independently a substrate. Project the P surface. The overlapping projection area PAO is an area (joint area) connecting the projection areas PR1 and PR3 and the projection area PR2.
In order to reduce the number of overlapping projection region PAOs with respect to the photomask 100, the longitudinal direction of the photomask 100 is preferably matched with the scanning direction (X direction).

FIG. 2B shows an example of an integrated exposure amount (time integration) of the exposure amount that the substrate P is exposed to by scanning the projection region PR (PR1, PR2, PR3). The horizontal axis indicates the position in the Y direction perpendicular to the X direction scanned by the projection area PR, and the vertical axis is the integrated exposure amount. In the region PAS (referred to as a single projection region or a single projection region) in which the projection region PR independently scans the substrate P, the integrated exposure amount is uniform in the Y direction, but the overlapping projection region PAO where the projection region PRs overlap each other. In (in the example shown in FIG. 2B), the integrated exposure amount tends to be higher than the integrated exposure amount of the single projection region PAS, but when it becomes higher or lower. Has a problem. In addition, it may be lower than the integrated exposure amount of the single projection area PAS.
The width of the single projection region PAS is, for example, several mm to several tens of mm, and the width of the overlapping projection region PAO is, for example, several hundred μm to several mm, but the present invention is not limited thereto.

FIG. 2B shows an example in which the integrated exposure amount in the overlapping projection area PAO is higher than the integrated exposure amount in the single projection area PAS, but it depends on the interval of the projection area PR (or the illumination area IL). Therefore, the integrated exposure amount of the overlapping projection area PAO changes, and may be lower than the integrated exposure amount of the single projection area PAS as described later.
Further, an example is shown in which there are a plurality of (two) peaks (maximum values) of the integrated exposure amount in the overlapping projection region PAO, but there is a case where the peak of the integrated exposure amount is one, and the values of the plurality of peaks are present. It may be different or it may indicate a local minimum rather than a maximum. FIG. 2B does not limit the distribution of the integrated exposure amount.

FIG. 2C is a graph showing the transmittance distribution of the photomask 100 that corrects the non-uniformity of the integrated exposure amount in the overlapping projection region PAO. The horizontal axis is the distance in the Y direction, and the vertical axis is the corrected transmittance.
In the example shown in FIG. 2A, since the integrated exposure amount of the overlapping projection area PAO is high, the area of the photomask 100 that projects the overlapping projection area PAO as shown in FIG. 2C (for example, “overlapping”). By reducing the transmittance of the "illuminated region"), the integrated exposure amount of the overlapping projection region PAO can be adjusted to be low, and the uniformity of the substrate P in the Y direction can be improved.
That is, in the photomask 100, by setting the transmittance of the region (overlapping illumination region) on which the overlapping projection region PAO is projected on the substrate P to be lower (or higher) than the transmittance of the other regions, the overlapping projection region is set. The exposure amount of PAO can be decreased (or increased).
For example, the illumination area on the photo mask 100 that projects the overlap projection area between the projection area PR1 and the projection area PR2 is an overlap area between the illumination area IL1 and the illumination area IL2, and the overlap illumination of the illumination area IL1 and the illumination area IL2. When the transmittance of the photomask 100 in the region is reduced (or increased), the intensity of the transmitted light in the overlapping projection region between the projection region PR1 and the projection region PR2 is reduced (or increased).

FIG. 2D is an enlarged plan view showing a part of the photomask 100. As shown in FIG. 2D, in the photomask 100, a semi-transmissive region 2 having a transmittance lower than the exposure light transmittance of the transmissive substrate 1 is formed on a transmissive substrate 1 such as quartz glass. , The semi-transmissive region 2 is formed in an overlapping illumination region that projects the overlapping projection region PAO. The semi-transmissive region 2 may be composed of the semi-transmissive membrane 3.
The semi-transmissive region 2 is a transmittance correction region that corrects (adjusts) the transmittance of the photomask 100, and therefore the semi-transmissive film 3 is a transmittance correction film that corrects the transmittance.
The transmittance correction area basically corresponds to an overlapping illumination area. However, as shown in FIG. 2B, the distribution of the integrated exposure amount is not determined only by the geometric shape of the overlapping illumination region, and the transmittance correction region does not necessarily match the shape of the overlapping illumination region.
In the following, for the sake of understanding, the transmittance correction region and the overlapping illumination region may be described in correspondence with each other, but as will be described later, the transmittance correction region is determined from the actual integrated exposure amount distribution.

The transmissive substrate 1 has a transmittance of, for example, 90 to 97% with respect to typical wavelengths (for example, i-line, h-line, and g-line) contained in the exposure light, and the transmissive film 3 (transmittance correction film). ) Is made of a known material such as a Cr-based metal compound, a Si-based compound, or a metal silicide compound, and is formed by a sputtering method, a vapor deposition method, or the like. Lower, for example 50% to 99%.
The region where the transparent substrate 1 is exposed is referred to as a transparent region 4.

When the integrated exposure amount of the overlapping projection area PAO is α times (α> 1) the integrated exposure amount of the single projection area PAS, the light transmittance of the semi-transmissive area 2 shall be 1 / α times that of the transmissive substrate 1. Therefore, the integrated exposure amount of the overlapping projection area PAO can be matched with the integrated exposure amount of the single projection area PAS.

As shown in FIG. 2B, the Y-direction-dependent distribution of the integrated exposure amount of the overlapping projection region PAO is not necessarily a rectangular shape that changes sharply, but a curved shape.
Therefore, α is calculated from the average value per unit area of the integrated exposure amount of the overlapping projection area PAO and the average value per unit area of the integrated exposure amount of the single projection area PAS, and the light transmittance of the semi-transmissive area 2 is calculated. decide.
α = <Integrated exposure of area PAO> / <Integrated exposure of area PAS>
Here, <> means an average value per unit area. The example shown in FIG. 2 shows the case of α> 1, and the example of α <1 will be described later.
The light transmittance of the semi-transmissive region 2 is not limited to the above value (1 / α times that of the transmissive substrate 1), and can be appropriately adjusted around the above value.

As described above, the photomask 100 has a scanning direction (moving direction) of the photomask 100 at least in a region (referred to as a transfer region) for projecting the formed transfer pattern onto the photosensitive material on the substrate P which is the transfer target. A semi-transmissive region (transmittance correction region) extending to the transfer region is formed over the entire length of the transfer region in the scanning direction.
As a result, the exposure unevenness of the transfer target can be reduced, and the transfer of a fine pattern becomes possible.

FIG. 3A shows a plan view of the photomask 100. The photomask 100 includes a semi-transmissive region 2 in an overlapping illumination region that projects the overlapping projection region PAO. Further, the photomask 100 shows an example in which the alignment mark AL is provided on the peripheral portion, but the present invention is not limited to this, and four or more locations may be arranged on the peripheral portion.

3 (b), (c), and (d) are enlarged plan views of the region surrounded by the circle in FIG. 3 (a), and show an example of the pattern of the semi-transmissive membrane 3. FIG. 3B shows an example (standard arrangement) in which a semi-transmissive film 3 having a transmittance 1 / α times that of the transmissive substrate 1 is formed in a single band shape in an overlapping illumination region where the transmittance should be adjusted. 3 (c) shows a plurality of strips in the overlapping illumination region where the transmittance should be adjusted so that the transmittance of the area average in the overlapping illumination region is 1 / α times the transmittance of the transmissive substrate 1. An example (leveling arrangement) in which the semi-transmittance film 3 (for example, a width of several tens of μm) is formed is shown. FIG. An example (random arrangement) in which a rectangular (for example, several tens of μm square) semi-transmittance film 3 is randomly arranged in an overlapping illumination region where the transmittance should be adjusted so as to have double the transmittance is shown.
The shapes of the leveling arrangement and the random arrangement are not limited to the above.

In the case of the pattern of the semitransparent film 3 shown in FIG. 3B, a steep change in the exposure amount occurs between the transmissive substrate 1 and the semitransparent region 2. On the other hand, in FIG. 3C, the irradiation intensity is set so as to approach the transmittance of the transmissive substrate 1 from the center of the overlapping illumination region toward the periphery. As a result, the amount of change in the transmittance of the photomask 100 in the scanning direction is relaxed, and the change in the actual integrated exposure amount can be approached. As a result, it is possible to further prevent the occurrence of exposure unevenness at the boundary between the transmissive substrate 1 and the semi-transmissive region 2.

Similarly, by adopting a random arrangement as shown in FIG. 3 (d), the change in the exposure amount between the transparent substrate 1 and the semi-transparent region 2 is alleviated. Similar to the pattern shown in FIG. 3C, the effect of further preventing the occurrence of exposure unevenness at the boundary between the transmissive substrate 1 and the semitransparent region 2 can be obtained.
Therefore, the width of the leveled and randomly arranged semi-transmissive regions 3 shown in FIGS. 3 (c) and 3 (d) is, for example, from the uniform single band-shaped semi-transmissive membrane 3 shown in FIG. 3 (b). On both sides of the standard arrangement, a width corresponding to the distribution (spreading at the end) of the integrated exposure amount of the region PAO or wider is set.

The transmittance of the semi-transmissive region 2 can be adjusted by, for example, the film thickness and composition of the semi-transmissive film 3 to be formed. It has, for example, 50% to 99% of the transmittance of the transmission region 4 with respect to the representative wavelength contained in the exposure light.
However, when it is difficult to stably form the semi-transmissive membrane 3 having a high transmittance of, for example, 70% or more, the transmittance is adjusted (corrected) by adjusting the occupancy rate (coverage) of the semi-transmissive film 3. )can do.
FIG. 4 shows a method of adjusting the transmittance of the semi-transmissive region 2. FIG. 4 (a) shows an occupancy rate of the semi-transmissive membrane 3 of 100%, and FIG. 4 (b) shows an occupancy rate of the semi-transmissive membrane of 50%. (= 1/2), FIG. 4 (c) shows a semi-permeable membrane occupancy rate of 25% (= 1/4), and FIG. 4 (d) shows a semi-permeable membrane occupancy rate of 12.5% (= 1 /). An example of 8) is shown.
The occupancy rate of the semi-transmissive membrane 3 in the semi-transmissive region 2 is the ratio of the formed area of the semi-transmissive membrane 3 to the area of the semi-transmissive region 2 (= [formation area of the semi-transmissive membrane 3] / [semi-transmissive region 2]. Area]).

For example, when the transmittance of the semi-transmissive film 3 with respect to the exposure light is 70%, the occupancy rate of the semi-transmissive film 3 in the semi-transmissive region 2 is 100% (FIG. 4 (a)) and 50% (FIG. 4 (b)). , 25% (FIG. 4 (c)) and 12.5% (FIG. 4 (d)), the transmittances of the semi-transmissive region 2 are 70%, 85%, 92.5%, and 96.25%, respectively. ..
By adjusting the transmittance of the semi-permeable membrane 3 itself and adjusting the occupancy of the semi-transmissive membrane 3, the required transmittance of the semi-transmissive region 2 can be obtained.

FIG. 5 is a plan view of a photomask 100 having a transmissive region 4 in which the transmissive substrate 1 is exposed, a semi-transmissive region 2 in which a semi-transmissive film 3 is formed, and a predetermined pattern 5 (mask pattern 5).
In the photomask 100, a light-shielding pattern 5 is formed on the semi-transmissive region 2 made of the semi-transmissive film 3.
Here, the pattern 5 is a pattern for forming an electronic circuit, an electronic component, or the like on the substrate P to be transferred.

The photomask 100 is not limited to a binary mask in which the pattern 5 is composed of only a light-shielding pattern, but is a multi-gradation halftone mask having a pattern composed of a light-shielding film and a translucent film, or a light-shielding. It may be a phase shift having a pattern composed of a sex film and a semi-transparent phase shift film.
Further, the relative relationship between the dimensions of the pattern 5 and the semitransparent region 2 in FIG. 5 is adjusted for visibility and does not necessarily reflect the actual dimensional ratio of the photomask 100.

(Embodiment 1)
Hereinafter, a method for manufacturing the photomask 100 according to the first embodiment will be described.
6 and 7 show cross-sectional views of a main manufacturing process of the photomask 100 having the pattern 5 made of the light-shielding film 6.
As shown in FIG. 6A, as a transmittance correction film for correcting the transmittance of the photomask 100 on a transparent substrate 1 such as quartz glass, for example, a metal compound such as a metal oxide film or a nitride film. A semi-permeable film 3 made of a known material such as a Si-based compound or a metal silicide compound is formed into a film by a sputtering method, a vapor deposition method or the like (for example, a film thickness of 1 [nm] to 10 [nm]). The composition and film thickness of the film are appropriately selected so as to obtain the transmittance required for correcting the transmittance in the overlapping illuminated area.
Preferably, the semi-transmissive film 3 has a transmittance lower than that of the transmissive substrate 1 and a higher transmittance than that of the light-shielding film 6 with respect to the representative wavelength contained in the exposure light, and the transmittance of the transmissive substrate 1 is preferable. A film having a high transmittance of 50% to 99%, more preferably 70% to 99%, for example, a metal oxide film having a high transmittance property (Cr-based, Zn-based, Sn-based). To use.
The configuration shown in FIG. 4 may be appropriately adopted for adjusting the transmittance.
The wavelength and transmittance of the exposure light are not limited to the above values.

Next, as shown in FIG. 6B, the first photoresist film 7 is formed by a coating method or the like, and then the first photoresist film 7 is patterned by a drawing and developing step.
The pattern of the first photoresist film 7 corresponds to the semi-transmissive region 2 in FIG. That is, the pattern of the first photoresist film 7 defines the semi-transmissive region 2 in FIG.
Next, the semi-transmissive film 3 is etched with the first photoresist film 7 as an etching mask by a wet etching method or a dry etching method, and patterned.
The pattern of the first photoresist film 7 may include an alignment mark.
For example, an alignment mark may be included in the peripheral portion of the photomask 100, for example, at the four corners.
Further, when patterning a light-shielding film or the like laminated on the upper layer with the alignment mark as a reference, the drawing device detects the position of the alignment mark and draws a pattern based on the design data. At this time, as will be described in detail later, if the transmittance of the semi-transmissive membrane 3 on which the alignment mark is formed is high, a position detection error of the alignment mark may occur, and countermeasures are required.

Next, as shown in FIG. 6C, the first photoresist film 7 is removed by immersing it in an ashing method or a resist stripping solution, and the etching stopper film 9 is removed by a sputtering method, a vapor deposition method, or the like (for example, a film). Thickness 1 [nm] to 20 [nm]) is formed.
After that, a light-shielding film 6 (upper layer film 6) made of a known material such as a metal compound, a Si-based compound, or a metal silicide compound is applied to the upper layer of the etching stopper film 9 by a sputtering method, a vapor deposition method, or the like (for example, a film thickness of 50 [. nm] to 100 [nm]) film formation.
The transmittance for the representative wavelength contained in the exposure light of the light-shielding film 6 is, for example, by adjusting the material (composition) and the film thickness, for example, the optical density (OD value) is 2.0 or more, preferably 2.7. Set to satisfy the above.
Here, the etching stopper film 9 is made of a material having different etching characteristics (having resistance) from the light-shielding film 6 and the semi-transmissive film 3, and a known material can be used.
When the alignment mark made of the semi-transmissive film 3 is formed on the photomask 100, the etching stopper film 9 and the light-shielding film 6 are covered with a shield plate or the like at the place where the alignment mark is formed at the time of film formation. May be formed to prevent the etching stopper film 9 and the light-shielding film 6 from being formed on the alignment mark.
As described above, when the transmissivity of the semi-transmissive film 3 on which the alignment mark is formed is high, it becomes difficult for the drawing apparatus to detect the position of the alignment mark, and an error in detecting the position of the alignment mark occurs. In some cases.
In such a case, after forming the semi-transparent film 3 on the transmissive substrate 1 in advance, a transmittance adjusting film for reducing the transmittance is provided in the region from the outside of the pattern forming region to the peripheral edge of the transmissive substrate 1. It may be laminated. The transmittance adjusting film is not limited to the semi-permeable film and may be a light-shielding film. However, the inside of the pattern region is formed in a state of being shielded by a shield plate or the like to prevent the formation of the transmittance adjusting film in the pattern region.

Next, as shown in FIG. 6D, the second photoresist film 8 is formed by a coating method or the like, and then the second photoresist film 8 is patterned by a drawing and developing step.
The pattern of the second photoresist film 8 corresponds to the pattern 5 of FIG. That is, the pattern of the second photoresist film 8 defines the pattern 5.

Next, as shown in FIG. 7A, the pattern of the second photoresist film 8 is used as an etching mask, and the light-shielding film 6 is selectively etched and patterned by a wet etching method or a dry etching method. ..
Since the light-shielding film 6 is made of a material different from that of the lower etching stopper film 9, the light-shielding film 6 is selected without etching the etching stopper film 9 using a known etchant (chemical solution or gas). Can be etched in a targeted manner.
Since the semi-transmissive film 3 is covered with the etching stopper film 9, it is not etched in this step.

Next, as shown in FIG. 7B, the pattern of the second photoresist film 8 is used as an etching mask, and the etching stopper film 9 is selectively etched and patterned by a wet etching method or a dry etching method. ..
Since the etching stopper film 9 is made of a material different from that of the light-shielding film 6 and the semi-transmissive film 3, the light-shielding film 6 and the semi-transmissive film 3 are not etched by using a known etchant (chemical solution or gas). , The etching stopper film 9 can be selectively etched.

Next, as shown in FIG. 7 (c), the second photoresist film 8 is removed by an ashing method or by immersing it in a resist stripping solution to obtain a photomask 100.
The etching stopper film 9 or the semi-transmissive film 3 exists in the lower layer of the light-shielding film 6, but by setting the film thickness thin, the mask quality including accuracy is not affected.

(Embodiment 2)
Hereinafter, a method for manufacturing the photomask 100 according to the second embodiment will be described.
8 and 9 show a cross-sectional view and a plan view of a main manufacturing process of a photomask 100 having a pattern 5 made of a light-shielding film 6. 8 (a), (b), (d), FIGS. 9 (a), 9 (c) correspond to the lines AA of FIG. 5, and the lines AA of FIGS. 8 (c) and 9 (b). 8 (c) and 9 (b) are plan views.
Hereinafter, a method for manufacturing the photomask 100 will be described with reference to FIGS. 8 and 9.

As shown in FIG. 8A, a semi-transmissive film 3 is used as a transmittance correction film for correcting the transmittance of the photomask 100 on a transparent substrate 1 such as quartz glass by a sputtering method, a vapor deposition method, or the like ( For example, a film thickness of 5 [nm] to 20 [nm]) is formed.

Next, a light-shielding film 6 (upper layer film) is formed on the semi-transmissive film 3 by a sputtering method, a vapor deposition method, or the like (for example, a film thickness of 50 [nm] to 100 [nm]).
The light-shielding film 6 is made of a material having different etching characteristics from the semi-transmissive film 3. For example, a Cr-based compound can be selected as the semi-transmissive film 3, and a metal-based compound other than Cr, for example, a Ti-based compound or a Ni-based compound can be selected as the light-shielding film 6, but the material is not limited thereto and is appropriately known. Should be combined.

Even if a photomask blank having a semi-transparent film 3 formed on a transmissive substrate 1 prepared in advance or a photomask blank having a semi-transmissive film 3 and a light-shielding film 6 formed on the transmissive substrate 1 can be used. good.

Next, as shown in FIGS. 8 (b) and 8 (c), the first photoresist film 7'is formed by a coating method or the like, and then the first photoresist film 7'is patterned by a drawing and developing step. ..
As shown in FIG. 8 (c), the pattern of the first photoresist film 7'is a pattern in which the semi-transmissive region 2 and the pattern 5 shown in FIG. 5 are added (combined).

Next, as shown in FIG. 8D, the first photoresist film 7'is used as an etching mask, and first, the light-shielding film 6 formed on the upper layer is selectively selected by a wet etching method or a dry etching method. Etch and pattern. Next, the semi-transmissive film 3 formed in the lower layer is selectively etched and patterned by a wet etching method or a dry etching method. Then, the first photoresist film 7'is removed by an ashing method or by immersing in a resist stripping solution.
By appropriately selecting a known etchant (chemical solution or gas), selective etching can be performed on each of the semi-transmissive film 3 and the light-shielding film 6.

In the step shown in FIG. 8D, the light-shielding film 6 and the half are used by using the first photoresist film 7'as an etching mask and using an etchant that simultaneously etches the light-shielding film 6 and the semi-transmissive film 3. The transmission film 3 may be etched. Although the amount of side etching of the light-shielding film 6 increases and the amount of variation in the pattern width of the light-shielding film 6 increases, there is an advantage that the manufacturing process is simplified.

Next, as shown in FIGS. 9A and 9B, a second photoresist film 8'is formed by a coating method or the like, and then the second photoresist film 8'is patterned by a drawing and developing step. ..
As shown in FIG. 9B, the pattern of the second photoresist film 8'corresponds to pattern 5 of FIG. That is, the pattern of the second photoresist film 8'defines pattern 5.

Next, as shown in FIG. 9C, the second photoresist film 8'is used as an etching mask, and the light-shielding film 6 formed on the upper layer is selectively etched by a wet etching method or a dry etching method. , Patterning. The semi-transmissive membrane 3 is left unetched.
Then, the second photoresist film 8'is removed by an ashing method or immersion in a resist stripping solution to obtain a photomask 100.

In FIG. 9C, the region where the light-shielding film 6 and the semi-transmissive film 3 are laminated has a light-shielding property and functions as a pattern 5. On the other hand, the single-layer region of the semi-transmissive film 3 functions as the semi-transmissive region 2, and can correct the transmittance of the photomask 100 and reduce the exposure unevenness.

The pattern of the first photoresist film 7'and the pattern of the second photoresist film 8'may appropriately include an alignment pattern in the peripheral portion of the photomask 100.
It is possible to obtain an alignment composed of the light-shielding film 6 (and / or the translucent film 3).

(Embodiment 3)
In the above embodiment, the semi-transmissive region 2 is formed by the semi-transmissive film 3, but it can also be formed by using the light-shielding film 6.
FIG. 10A is a plan view showing an example in which the semi-transmissive region 2 is formed by a pattern in which a rectangular light-shielding film 6 (for example, a rectangular shape having a side length of 10 to 2 μm) is arranged in a staggered manner. 10 (b) and 10 (c) are cross-sectional views taken along the line AA showing the main manufacturing process of the photomask 100.
For example, by adjusting the occupancy rate (coverage rate) of the light-shielding film 6 as in the arrangement shown in FIG. 4, it is possible to adjust the average transmittance in the semi-transmissive region 2.

Hereinafter, the manufacturing process of the photomask 100 according to the third embodiment will be described.
As shown in FIG. 10B, a light-shielding film 6 is formed on the transparent substrate 1, and then a first photoresist film 7'' is formed by a coating method or the like. After that, the first photoresist film 7'' is patterned by the drawing and developing steps.
A photomask blank having a light-shielding film 6 formed on the transparent substrate 1 in advance may be used.

The pattern of the first photoresist film 7'' constitutes a region corresponding to the semi-transmissive region 2 (transmittance correction region) by a staggered pattern in which the transparent substrate 1 is partially covered with the light-shielding film 6, and is transparent. A region corresponding to the pattern 5 is formed by a pattern that completely covers the substrate 1 with the light-shielding film 6. The region where the semi-transparent region 2 and the pattern 5 overlap is the region of the pattern 5.
Similar to the configuration shown in FIG. 4, the transmittance of the semi-transmissive region 2 can be adjusted by the occupancy rate (coverage rate) of the light-shielding film 6.

Next, as shown in FIG. 10 (c), the light-shielding film 6 is etched with the pattern of the first photoresist film 7 ″ on an etching mask, and then the first photoresist film 7 ″ is ashed or resisted. It is removed by immersing it in a stripping solution to obtain a photoresist 100.

The pattern of the light-shielding film 6 formed in the semi-transparent region 2 is not limited to the staggered pattern (check-like pattern), and may be formed in a grid pattern, for example, and the transparent substrate 1 is exposed. The shape of the pattern can be arbitrarily set as long as the area ratio between the transmission region 4 and the light-shielding film 6 can be adjusted.

(Embodiment 4)
In each of the above embodiments, the semi-transmissive film 3 is formed as a method of forming the semi-transparent region 2 on the transmissive substrate 1, but by implanting ions into the transmissive substrate 1 to reduce the transmittance. The semi-transmissive region 2 may be formed.
In the present embodiment, the pattern of the first photoresist film 7 shown in FIG. 6B is substantially inverted, the semi-transmissive region 2 is opened, and the pattern of the photoresist film masking the other regions is transmitted. It is formed directly above the sex substrate 1, and a photoresist film is injected into the permeability substrate 1 with a mask to correct the transmittance. The transmittance of the injection layer into which the ions are injected decreases.
As the element to be injected, for example, As, Sb, Ge, Ga, Ti, W and the like can be used. The injection amount is appropriately selected according to the required light transmittance, for example, 1 × 10 ¹⁴ to 1 × 10 ¹⁸ [/ cm ² ]. In addition to the ion implantation device, an element may be implanted by a FIB device.
Since the semi-transmissive region 2 is formed by ion implantation, no special membrane is formed in the semi-permeable region 2. Therefore, in the subsequent manufacturing process, the conventional mask manufacturing process can be executed.
In this embodiment, it is necessary to form an alignment mark in advance on the transparent substrate 1 of the photomask 100.
Further, the first photoresist film 7 may be formed after the pattern of the photomask 100 and the alignment mark are formed according to the conventional mask manufacturing process, and ions may be implanted into the region corresponding to the semitransparent region 2.

(Embodiment 5)
In the above embodiment, the case where the integrated exposure amount of the overlapping projection area PAO is larger than the integrated exposure amount of the single projection area PAS (α> 1) has been described. However, since the integrated exposure amount of the overlapping projection region PAO changes depending on the interval and shape of the illumination region IL (IL1 to IL7), the value of α may be smaller than 1.
FIG. 11A shows the position dependence of the integrated exposure amount of the exposure amount to which the substrate P is exposed in the Y direction in the same manner as in FIG. 2B, and the integrated exposure amount of the overlapping projection area PAO is the single projection area. An example in which the exposure amount is smaller than the integrated exposure amount of PAS is shown.
FIG. 11B shows an example of the Y-direction distribution of the transmittance of the photomask 100 for correcting the non-uniformity of the integrated exposure amount in the overlapping projection region PAO, similarly to FIG. 2C.
In the example shown in FIG. 11A, the integrated exposure amount of the overlapping projection area PAO is lower than that of the surrounding integrated exposure amount. Therefore, as shown in FIG. 11B, the photo projecting the overlapping projection area PAO is performed. It is necessary to increase the transmittance of the overlapping illumination area of the mask 100 as compared with the transmittance of the surroundings.

In the present embodiment, unlike the example shown in FIG. 2 (d), as shown in FIG. 11 (c), the region on the photomask 100 corresponding to the overlapping projection region PAO is set as the transmissive region 4, and other regions are used. The region on the photomask 100 corresponding to the single projection region PAS may be set as the semitransparent region 2 to reduce the transmittance. In this case, the overlap projection region PAO exposed by the transmissive substrate 1 is made to function as a transmittance correction region by relatively increasing the transmittance of the overlap projection region PAO with reference to the single projection region PAS.
Therefore, as shown in FIG. 11D, the semi-transmissive film 3 is formed in the illumination region on the photomask 100 corresponding to the single projection region PAS.

For the patterning of the semi-permeable membrane 3, any of the above embodiments 1, 2 and 3 may be adopted. In the first, second and third embodiments, the positions of the transparent region 4 and the semi-transparent region 2 may be exchanged. In the fourth embodiment, the pattern of the photoresist film in which the semi-transmissive region 2 is opened is used.

In this way, not only the transmittance of the region on the photomask 100 corresponding to the overlapping projection region PAO is reduced, but also the transmittance of the region on the photomask 100 corresponding to the single projection region PAS is reduced, thereby integrating. It is also possible to make the exposure amount uniform. By providing the transmittance correction region on the photomask 100, it is possible to flexibly reduce the exposure unevenness of the exposure apparatus 200.
Therefore, even if the interval of each illumination area IL (IL1 to IL7) varies, and the width of the plurality of overlapping projection areas PAO and the integrated exposure amount vary, the light transmittance is relatively relative to the single projection area PAS. By forming different transmittance correction regions over the entire length of the transfer region (total projection region) of the photomask 100 in the scanning direction, the integrated exposure amount of the overlapping projection region PAO and the single projection region PAS can be made uniform. Can be done.

FIG. 12 is a plan view showing the arrangement of the transmittance correction region for correcting the transmittance of the transfer region of the photomask 100 in order to reduce the exposure unevenness of the exposure apparatus 200.
As shown in FIG. 12, the photomask 100 according to the present invention corresponds to one or more overlapping projection region PAOs arranged adjacent to the reference region 101, respectively, with the single projection region PAS as the reference region 101 for the transmittance. It is provided with a transmittance correction region (102a, 102b, 102c).
To make the integrated exposure amount uniform by setting the transmittance relative to the transmittance of the reference area 101 based on the ratio of the integrated exposure amount of the single projection area PAS and each overlapping projection area PAO. Can be done. Further, the transmittances of the respective transmittance correction regions (102a, 102b, 102c) may be the same or different.
Further, the transmittance of the transmittance correction region (102a, 102b, 102c) can be set relatively high or low with respect to the transmittance of the reference region 101.
By providing the transmittance correction region in the photomask 100 in this way, more precise transmittance correction becomes possible, and a more accurate pattern can be projected on the substrate P.

(Measurement of exposure)
In order to form the semi-transmissive region 2 of the photomask 100, it is necessary to measure the position of the overlapping projection region PAO projected on the substrate P and the integrated exposure amount.
Further, it is necessary to clarify the positional relationship between the overlapping projection region PAO projected on the substrate P and the corresponding photomask 100.
The correspondence between the overlapping projection area PAO and the coordinates on the photomask 100 will be clarified below, and a method for measuring the integrated exposure amount will be described.

As shown in FIG. 13A, an image sensor (one-dimensional or two-dimensional detector) in which an optical detector 10, for example, an optical sensor such as a CCD or CMOS sensor is arranged is installed (mounted) on the substrate P. .. As the optical detector 10, for example, a commercially available linear image sensor can be used.
For the measurement of the integrated exposure amount on the substrate P, the substrate P used in the actual product is preferably used, but a dummy substrate having the same shape (width, depth, thickness) may be used. ..
When the optical detector 10 is, for example, a one-dimensional linear image sensor, a plurality of optical sensors are aligned in a row, and the substrate P is such that the rows of photosensors are aligned in the Y direction (direction perpendicular to the scanning direction). Install in.
The optical detector 10 outputs the position (arrangement location) of each optical sensor and the intensity of light detected by each optical sensor to an arithmetic processing device such as a computer every moment. The arithmetic processing device calculates the integrated exposure amount by integrating (time integration) the light intensity at each measurement time output from each optical sensor.
As shown in FIG. 13A, a plurality of optical detectors 10 may be installed.

When the optical detector 10 is installed on the substrate P, it is difficult to accurately match the scanning direction of the optical system with the direction of the row of optical sensors, and the arrangement direction and the arrangement direction of each photosensor in the optical detector 10 and As shown in FIG. 13B, the calibration photomask 100 provided with the light-shielding reference pattern 11 in order to acquire an accurate relative positional relationship between the position and the scanning direction of the optical system and the position on the substrate P. 'Prepare. The photomask 100'is provided with an alignment mark on the peripheral portion, and is aligned and held on the mask stage of the exposure apparatus 200.

The reference pattern 11 is composed of, for example, a plurality of rectangular (5 μm × 2 μm, etc.) partial patterns (11a, 11b, 11c ... 11x) arranged in a row in the Y direction.
Further, a plurality of reference patterns 11 are arranged apart from each other in the X direction, and therefore rectangular partial patterns (11a, 11b, 11c ... 11x) are arranged in a staggered manner.
The positions (coordinates) of the partial patterns (11a, 11b, 11c ... 11x) are stored in the storage device as data.

The calibration photomask 100'and the substrate P are moved in synchronization with each other, and the image of the reference pattern 11 provided on the calibration photomask 100'is projected onto the substrate P.
The intensity distribution (luminance distribution) in the Y direction of the light projected through the calibration photomask 100'can be measured by the optical detector 10 installed on the substrate P. The intensity distribution corresponds to the exposure distribution for exposing the photoresist film on the substrate P.
The arithmetic processing device integrates the output value of the light intensity measured by each optical sensor, and stores it in the storage device as the integrated light intensity (integrated exposure amount) corresponding to each optical sensor.
Since the exposure light is shielded by the partial pattern (11a, 11b, 11c ... 11x) of the reference pattern 11, the optical detector 10 has the light corresponding to the partial pattern (11a, 11b, 11c ... 11x). Intensity distribution can be detected.
The arithmetic processing unit is the position on the calibration photomask 100'and the reference pattern 11 from the position of the partial pattern (11a, 11b, 11c ... 11x) stored in the output of the optical detector 10 and the storage device. The correlation with the partial pattern (11a, 11b, 11c ... 11x) can be calculated.

Further, since the arithmetic processing device stores the integrated light intensity (integrated exposure amount) of each optical sensor, the calibration photomask is based on the correlation between the position of the obtained calibration photomask 100'and the position of the optical sensor. The integrated light intensity distribution (integrated exposure amount distribution) in the Y direction on 100'can be measured, and the position of the overlapping projection region PAO can be detected.
It should be noted that the spatial resolution may be further improved by calculating the light intensity at the position between the optical sensors by interpolation by the image processing technique.

Further, after the position of the substrate P is moved by a predetermined distance in the X direction (scanning direction) with respect to the calibration photomask 100', the exposure is performed while the calibration photomask 100'and the substrate P are moved in synchronization with each other. Processing may be performed.
Since the reference pattern 11 formed on the calibration photomask 100'is arranged in a staggered pattern (11a, 11b, 11c ... 11x), different partial patterns (11a, 11b, 11c ... The exposure amount distribution data can be acquired for the position coordinates of 11x). As a result, the measurement error can be reduced and the position of the overlapping projection region PAO can be determined more accurately.
The measurement result of the calibration photomask 100'is used for designing the reference region and the transmittance correction region of the photomask 100.

In general, a linear image sensor (one-dimensional detector) has better spatial resolution than a two-dimensional detector, so an example of a linear image sensor was described in the figure, but a two-dimensional array of photodetectors is described. A detector may be used. In the case of a two-dimensional image sensor, since the optical sensor is arranged on grid points along two orthogonal axes, it is installed on the substrate P so that one axis is aligned in the Y direction (perpendicular to the scanning direction). do.

In this way, the positional coordinates of the transmittance correction area on the mask 100 and the reference area adjacent to the mask 100 are determined from the integrated exposure amount distribution, and the correction value of the transmittance of the transmittance correction area relative to the reference area is further determined. can do.
Then, based on this measurement result, the transmittance, composition, film thickness, occupancy rate, occupancy rate of the light-shielding film 3 and the like of the semi-transmissive film 3 can be determined, and the photomask 100 can be manufactured.
When the corrected value of the relative transmittance in the transmittance correction region is higher than the transmittance in the reference region, the transmittance in the reference region is adjusted by forming the semi-transmissive film 3 or partially forming a light-shielding film. By covering it, it may be lowered and the transmittance of the reference region may be relatively increased.

Further, since the integrated exposure amount of the exposure apparatus 200 that actually uses the photomask 100 is actually measured, the exposure unevenness is reduced according to the state of the exposure apparatus, so that the optimum integrated exposure amount can be corrected. It is also possible to customize the photomask 100 for the exposure apparatus 200.
Further, the accuracy of calculating the positions of the reference region and the transmittance correction region can be determined according to the customer specifications.

It is also possible to determine the position of the overlapping projection region PAO without installing the optical detector 10 on the substrate P.
14 (a) and 14 (b) are enlarged plan views of the measuring photomask 100'' provided with the measuring pattern 12, and FIGS. 14 (c) and 14 (d) are formed on the substrate P. It is a photoresist film 13, and is an enlarged plan view of the photoresist film 13 after being patterned using the measurement pattern 12.
FIG. 14A shows an example of a measurement pattern 12 consisting of a linear pattern extending in the Y direction (direction perpendicular to the scanning direction), and FIG. 14B shows a rectangular hole pattern aligned in the Y direction. An example of the measurement pattern 12 comprising the above is shown.
The measurement photomask 100'' has an alignment mark on the peripheral portion, and is aligned and held on the mask stage of the exposure apparatus 200.

As shown in FIG. 14A, the measurement pattern 12 is composed of a plurality of line patterns, and the line pattern is such that a plurality of line patterns having a width of, for example, 10 to 1 μm are projected onto the substrate P. It is configured in. The widths of the line patterns may be the same or different.
As shown in FIG. 14 (c), the photoresist film 13 formed on the substrate P is subjected to the substrate P and the measurement photo using a measurement photomask 100'' provided with a measurement pattern 12 composed of a line pattern. The photoresist film 13 is patterned by being exposed and developed by the exposure apparatus 200 while moving in synchronization with the mask 100''. The width (length in the X direction) of the patterned photoresist film 13 is measured at equal intervals in the Y direction (at the point indicated by the middle arrow in FIG. 14C), and the width of the photoresist film 13 depends on the Y direction. Seeking sex.
By separately measuring the correlation between the width of the photoresist film 13 and the integrated exposure amount, the integrated exposure amount distribution in the Y direction can be obtained from the Y-direction dependence of the width of the photoresist film 13. Further, by calculating the integrated exposure amount distribution in the Y direction based on the Y direction dependence of the width of the photoresist film 13 transferred using the measurement patterns 12 having different widths, more accurate integrated exposure amount distribution data. It is also possible to obtain.
The width of the photoresist film 13 can be automatically measured by an electron microscope for length measurement, and can be easily measured.

Further, since the taper shape of the photoresist film 13 depends on the integrated exposure amount, it is also possible to obtain the integrated exposure amount distribution in the Y direction from the Y-direction dependence of the taper shape of the photoresist film 13. The width of the top (upper surface) and the width of the bottom (bottom) of the photoresist film 13 can be measured with an electron microscope for length measurement, and the taper shape of the photoresist film 13 can be calculated from the difference. That is, by separately measuring the correlation between the difference between the width of the top and the width of the bottom of the photoresist film 13 and the integrated exposure amount, the width of the top and bottom of the photoresist film 13 (reflecting the tapered shape). The integrated exposure amount distribution in the Y direction may be obtained from the dependence of the difference in the Y direction. The width of the top and the width of the bottom of the photoresist film 13 can be automatically measured by a length measuring electron microscope from the change in the contrast of the planar SEM image of the photoresist film 13, and can be easily measured.

Further, a hole type measurement pattern 12 as shown in FIG. 14B may be used. It is configured so that a hole having a size of, for example, 10 to 1 μm can be projected on the substrate P.
As shown in FIG. 14D, the photoresist film 13 formed on the substrate P is exposed using a hole-type measurement pattern 12, the transferred hole diameter is measured, and holes in the Y direction are measured. Find the diameter dependence.
By separately measuring the correlation between the hole diameter of the photoresist film 13 and the integrated exposure amount, the integrated exposure amount distribution in the Y direction can be obtained from the hole diameter dependence in the Y direction.
Since the holes of the measurement pattern 12 are arranged in a staggered pattern, the measurement interval of the hole diameter in the Y direction can be reduced.

By patterning the photoresist film formed on the substrate P using the measurement photomask 100'' provided with the measurement pattern 12 in this way and measuring the shape of the patterned photoresist film, the photoresist film is formed on the substrate P. The integrated exposure amount distribution in the Y direction can be obtained.
Since the dimension measurement interval can be arbitrarily set by the length measuring electron microscope, the spatial resolution is superior to that of the optical detector 10.
The measurement result of the measurement photomask 100'' is applied to the photomask 100.
The measurement pattern 12 is not limited to the above shape, and can be appropriately set.

INDUSTRIAL APPLICABILITY The present invention makes it possible to provide a photomask that reduces the influence of exposure unevenness of an exposure apparatus, and makes it possible to reduce variations in the size of an exposed pattern. In particular, in the manufacturing process of a large-area substrate such as a large-sized display, the effect of reducing exposure unevenness is remarkable, and the industrial applicability is great.

200 Exposure device 201 Light source 202 Branch optical system 203, 2031 to 2037 Illumination optical system 204, 2041 to 2047 Projection optical system IL, IL1 to IL7 Illumination area PR, PR1 to PR7 Projection area PAO Overlapping projection area PAS Single projection area (single projection) region)
P Substrate 100 Photomask 1 Transmissive substrate 2 Semi-transmissive region 3 Semi-transmissive film 4 Transmissive region 5 Pattern, Mask pattern 6 Light-shielding film (upper layer film)
7 First photoresist film 7'First photoresist film 7'''First photoresist film 8 Second photoresist film 8'Second photoresist film 9 Etching stopper film 10 Optical detector 101 reference Regions 102a, 102b, 102c Transmission correction region 100'Calibration photomask 11 Reference pattern 11a to 11x Partial pattern 100'' Measurement photomask 12 Measurement pattern 13 photoresist film

Claims (8)

The transmissive substrate has a reference region and at least one transmittance correction region adjacent to the reference region.
The transmittance correction region extends over the entire length of the transfer region and extends.
A photomask characterized in that the light transmittance of the transmittance correction region and the reference region are different. The photomask according to claim 1, wherein a plurality of the transmittance correction regions are provided, and the plurality of the transmittance correction regions extend in the same direction. A semi-transmissive film is formed in the region having a low transmittance among the transmittance correction region and the reference region.
The photomask according to claim 1 or 2, wherein the transmittance of the semi-transmissive membrane is lower than the transmittance of the transparent substrate. The photomask according to claim 3, wherein the semi-transmissive film is partially formed and the light transmittance is controlled by the occupancy rate of the semi-transmissive film. The photomask has a light-shielding pattern and has a light-shielding pattern.
The third or four claim, wherein the light-shielding pattern includes at least one of a laminated structure of a light-shielding film and an etching stopper film or a laminated structure of a light-shielding film and an etching stopper film and the semi-transmissive film. Photomask. The photomask has a light-shielding pattern and has a light-shielding pattern.
The photomask according to claim 3 or 4, wherein the light-shielding pattern has a laminated structure of the light-shielding film and the semi-transmissive film. In the region of the transmittance correction region and the reference region where the transmittance is low, the transmissive substrate is partially covered with a light-shielding film, and the light transmittance is controlled by the occupancy of the light-shielding film. The photomask according to claim 1 or 2, wherein the photomask is characterized. The process of measuring the integrated exposure amount distribution of the exposure equipment and
From the integrated exposure amount distribution, a step of determining the positions of the reference region and the transmittance correction region of the photomask and calculating the correction value of the transmittance of the transmittance correction region relative to the reference region.
The photomask according to any one of claims 1 to 7, further comprising a step of correcting the transmittance of the transmittance correction region relative to the reference region based on the correction value. Manufacturing method.

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