JP2018136584A - Production method of photomask for display device, drawing device for production of display device, inspection method of photomask for display device production, and inspection device of photomask for display device production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photomask production method capable of enhancing coordinate accuracy of a pattern formed on a subject to be transferred.SOLUTION: A photomask production method of the present invention includes: a step of preparing pattern designing data A; a step of obtaining transfer surface shape data C showing a difference portion of a main surface caused by holding the photomask to an exposure device; a step of obtaining height distribution data E during drawing that shows a height distribution of a main surface in a state where a photomask blank is placed on a stage of the drawing device; a step of obtaining drawing difference data F due to a difference between height distribution data E during drawing and transfer surface shape data C; a step of obtaining drawing coordinate deviation amount data G by calculating the coordinate deviation amount corresponding to the drawing difference data F; and a step of drawing a drawing on the photomask blank by using the drawing coordinate deviation amount data G and the pattern designing data A.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a photomask that is advantageously used in the manufacture of semiconductor devices and display devices (LCD, organic EL, etc.), and relates to a manufacturing method and apparatus, and an inspection method and apparatus.

  It is desired to increase the accuracy of the transfer pattern formed on the photomask, and to increase the inspection accuracy of the formed transfer pattern.

  Patent Document 1 (Japanese Patent Laid-Open No. 2010-134433) describes a drawing method and a drawing apparatus capable of increasing the coordinate accuracy when a photomask pattern is transferred onto a transfer target. In particular, in the photomask manufacturing process, the film surface (pattern formation surface) when drawing the transfer pattern is different from the exposure pattern, eliminating the problem that the designed pattern is not formed on the transfer target. Therefore, a method for obtaining corrected drawing data is described.

JP 2010-134433 A

  In manufacturing a display device, a photomask having a transfer pattern based on the design of a device to be obtained is often used. As a device, a liquid crystal display device and an organic EL display device typified by a smartphone or a tablet terminal are required to have beautiful images with high brightness, low power consumption, high operation speed, and high resolution. For this reason, a new technical problem has been revealed by the inventors with respect to the photomask used in the above-described applications.

  In order to express a fine image clearly, it is necessary to increase the pixel density. Currently, a device exceeding a pixel density of 400 ppi (pixel per inch) is being realized. For this reason, the design of the photomask transfer pattern is in the direction of miniaturization and high density. By the way, many electronic devices including a display device are three-dimensionally formed by stacking a plurality of layers on which fine patterns are formed. Therefore, it is important to improve the coordinate accuracy of these multiple layers and to coordinate each other. That is, if the pattern coordinate accuracy of each layer does not satisfy a predetermined level, there is a problem that proper operation does not occur in the completed device. Therefore, the allowable range of coordinate deviation required for each layer is gradually decreasing.

  By the way, according to Patent Document 1, the shape change between the shape of the film surface in the photomask blank drawing process and the shape of the film surface at the time of exposure is calculated, and drawing is performed based on the calculated shape change. It describes that the design drawing data to be used is corrected. In this document, at the stage of drawing the transfer pattern, the film surface of the substrate (the surface on the film forming side in the transparent substrate, the surface on which the film is formed in the photomask blank, and the pattern in the photomask The method of obtaining corrected drawing data by distinguishing the amount of deformation from the ideal plane in FIG. 2) that remains during exposure and the amount that disappears during exposure is described.

When a pattern is drawn on a photomask blank with a photoresist by a drawing device, the photomask blank is placed on a stage of the drawing device with the film surface facing upward. At that time, the deformation factor from the ideal plane of the surface shape of the film surface of the photomask blank is
(1) Inadequate flatness of the stage,
(2) Deflection of the substrate due to foreign object pinching on the stage,
(3) Photomask blank film surface irregularities,
(4) Deformation of the film surface due to irregularities on the back surface of the photomask blank,
It is thought that there is. Accordingly, the surface shape of the photomask blank in this state is formed by accumulating the above four factors. Then, drawing is performed on the photomask blank in this state.

  On the other hand, when the photomask is mounted on the exposure apparatus, it is fixed with the film surface facing downward and supporting only the peripheral edge of the photomask. Place the transfer object (also referred to as the object to be processed because the pattern is transferred and then processed by etching, etc.) under the photomask from above the photomask (from the back side). Irradiate exposure light. In this state, among the above four deformation factors, (1) insufficient flatness of the stage and (2) deflection of the substrate due to foreign matter pinching on the stage disappear. Further, (4) irregularities on the back surface of the substrate remain even in this state, but the surface shape of the back surface where the pattern is not formed does not affect the transfer of the front surface (pattern forming surface). On the other hand, the deformation factor that remains even when the photomask is used in an exposure apparatus is (3) above.

  That is, the deformation factors (1), (2), and (4) exist at the time of drawing and disappear at the time of exposure. Due to this change, a coordinate shift between drawing and exposure occurs. Therefore, while the above (1), (2), and (4) are factors, the change in the surface shape from the ideal plane is corrected to the drawing data, while (3) is the factor. If the change in the surface shape is not reflected in the correction, a photomask having a more accurate coordinate design data transfer performance can be obtained.

  Therefore, according to the method of Patent Document 1, it is possible to improve the coordinate accuracy of the pattern formed on the transferred body.

  On the other hand, the photomask in the exposure apparatus is held and supported by the holding member of the exposure apparatus in a holding area near the periphery of the substrate, and thus the substrate is deformed by being forcedly restrained. Further, in the case of a photomask for manufacturing a display device or the like, since a large area substrate is supported only near the periphery of the substrate, the influence of deflection due to its own weight cannot be ignored. In this case, the deformation indicated by the film surface may affect the area where the pattern of the photomask is formed, and may deteriorate the coordinate accuracy. The present inventor has found that it is meaningful to take into account such minute influences in consideration of pattern miniaturization and high integration in high-performance display devices and the like that are currently being developed.

  For example, a device such as a display device is formed by laminating patterned thin films, and each layer to be laminated is formed by a transfer pattern of each different photomask. Needless to say, the individual photomasks used are manufactured under strict quality control. However, as long as the individual photomasks are different, it is difficult to make the flatness of the surface all the same as the ideal plane, and the film surface shape must be perfectly matched in a plurality of photomasks. It is also difficult.

  Therefore, there is an individual difference in the film surface shape in each photomask, and the drawing data considering these factors in consideration of the film surface shape shown when these individual photomasks are held in the exposure apparatus. If this correction is performed, a transfer pattern with higher coordinate accuracy can be formed.

  That is, by the method of Patent Document 1, significant accuracy improvement can be obtained by preventing deterioration of coordinate accuracy due to the difference in film surface posture at the time of drawing and exposure. In order to increase the yield of devices, it is necessary to consider the slight individual differences in the film surface shape of the photomask substrate used in each layer, and the effect of the force that they receive in the exposure apparatus. It has been found by the present inventors that a method that substantially eliminates degradation is beneficial.

  Accordingly, the present invention provides a photomask manufacturing method, a drawing apparatus, a photomask inspection method, a photomask inspection apparatus, and a display apparatus manufacturing method capable of increasing the coordinate accuracy of a pattern formed on a transfer target. The purpose is to provide.

In order to solve the above-described problems, the present invention has the following configuration.
(Configuration 1)
In a photomask manufacturing method, comprising preparing a photomask blank in which a thin film and a photoresist film are formed on a main surface of a substrate, and drawing a predetermined transfer pattern by a drawing apparatus.
Preparing pattern design data A based on the design of the predetermined transfer pattern;
A step of obtaining transfer surface shape data C indicating the shape of the main surface when the photomask is held in an exposure apparatus;
On the stage of the drawing apparatus, obtaining the height distribution data E at the time of drawing indicating the height distribution of the main surface in a state where the photomask blank is placed with the main surface facing up,
Using the drawing height distribution data E and the transfer surface shape data C to obtain drawing difference data F;
At a plurality of points on the main surface, calculating a coordinate deviation amount corresponding to the drawing difference data F, and obtaining drawing coordinate deviation amount data G;
A photomask manufacturing method, comprising: a drawing step of drawing on the photomask blank using the drawing coordinate deviation amount data G and the pattern design data A.

(Configuration 2)
In a photomask manufacturing method, comprising preparing a photomask blank in which a thin film and a photoresist film are formed on a main surface of a substrate, and drawing a predetermined transfer pattern by a drawing apparatus.
Preparing pattern design data A based on the design of the predetermined transfer pattern;
A step of preparing substrate surface shape data B obtained by measuring the surface shape of the main surface,
When the photomask is held in the exposure apparatus, the transfer surface shape data C is obtained by reflecting the displacement generated in the surface shape on the substrate surface shape data B based on the shape of the holding member. Process,
On the stage of the drawing apparatus, measuring the height distribution of the main surface in a state where the photomask blank is placed with the main surface facing up, and obtaining height distribution data E during drawing; ,
Using the drawing height distribution data E and the transfer surface shape data C to obtain drawing difference data F;
A step of calculating coordinate deviation amount G at a plurality of points on the main surface corresponding to the drawing difference data F to obtain drawing coordinate deviation amount data G;
A photomask manufacturing method, comprising: a drawing step of drawing on the photomask blank using the drawing coordinate deviation amount data G and the pattern design data A.
(Configuration 3)
3. The photomask manufacturing method according to Configuration 2, wherein a finite element method is used in the step of obtaining the transfer surface shape data C.

(Configuration 4)
In the drawing step, drawing is performed using the correction pattern data H obtained by correcting the pattern design data A based on the drawing coordinate deviation amount data G. Configuration 1 The manufacturing method of the photomask in any one of -3.

(Configuration 5)
In the drawing step, the coordinate system of the drawing apparatus is corrected based on the drawing coordinate deviation amount data G, and drawing is performed using the obtained corrected coordinate system and the pattern design data A. The manufacturing method of the photomask in any one of the structures 1-3.

(Configuration 6)
The photomask according to any one of configurations 1 to 5, wherein when the photomask is held in an exposure apparatus, a plurality of holding points held by a holding member are arranged on a plane. Production method.

(Configuration 7)
The substrate surface shape data B is the position of a plurality of measurement points on the main surface in a state where the photomask blank or the substrate for making the photomask blank is held so that the main surface is vertical. The photomask manufacturing method according to any one of Configurations 2 to 6, wherein the photomask manufacturing method is obtained by measuring

(Configuration 8)
A drawing apparatus used for drawing a transfer pattern on a photomask blank in which a thin film and a photoresist film are formed on a main surface of a substrate,
In the state where the photomask blank is placed on the stage with the main surface facing up, the height distribution of the main surface is measured to obtain drawing height distribution data E,
Input means for inputting pattern design data A of the transfer pattern, and transfer surface shape data C indicating the main surface shape of the substrate in a state where the substrate is held in an exposure apparatus;
Using the drawing height distribution data E and the transfer surface shape data C, calculation means for calculating drawing coordinate deviation amount data G at a plurality of points on the main surface;
A drawing apparatus comprising drawing means for drawing on the photomask blank using the drawing coordinate deviation amount data G and the pattern design data A.
(Configuration 9)
A drawing apparatus used for drawing a transfer pattern on a photomask blank in which a thin film and a photoresist film are formed on a main surface of a substrate,
In the state where the photomask blank is placed on the stage with the main surface facing up, the height distribution of the main surface is measured to obtain drawing height distribution data E,
Pattern design data A for the transfer pattern,
Substrate surface shape data B indicating the shape of the main surface of the substrate,
Information about the holding state when holding the substrate in the exposure apparatus;
And substrate physical property information including physical property values of the substrate material,
An input means for inputting
Using the substrate surface shape data B, the information on the holding state, and the substrate physical property information, the transfer surface shape data C indicating the main surface shape of the substrate held in an exposure apparatus is calculated, Using the drawing height distribution data E and the transfer surface shape data C, calculation means for calculating drawing coordinate deviation amount data G at a plurality of points on the main surface;
A drawing apparatus comprising drawing means for drawing on the photomask blank using the drawing coordinate deviation amount data G and the pattern design data A.

(Configuration 10)
In a photomask inspection method for inspecting a photomask having a transfer pattern formed by patterning a thin film on a main surface of a substrate using an inspection apparatus,
In a state where the photomask is placed on the stage of the inspection apparatus, a coordinate measurement of a pattern formed on the main surface is performed to obtain pattern coordinate data L;
A step of obtaining transfer surface shape data C indicating the shape of the main surface when the photomask is held in an exposure apparatus;
On the stage of the inspection apparatus, with the main surface facing up, with the photomask mounted, measuring the height distribution of the main surface to obtain inspection height distribution data I;
Using the inspection height distribution data I and the transfer surface shape data C, obtaining inspection difference data J;
A step of calculating a coordinate deviation amount K at a plurality of points on the main surface corresponding to the inspection difference data J to obtain inspection coordinate deviation amount data K;
A photomask inspection method comprising a step of inspecting the transfer pattern using the inspection coordinate deviation amount data K and the pattern coordinate data L.

(Configuration 11)
In a photomask inspection method for inspecting a photomask having a transfer pattern formed by patterning a thin film on a main surface of a substrate using an inspection apparatus,
In a state where the photomask is placed on the stage of the inspection apparatus, a coordinate measurement of a pattern formed on the main surface is performed to obtain pattern coordinate data L;
A step of preparing substrate surface shape data B obtained by measuring the surface shape of the main surface,
A step of reflecting the displacement generated in the surface shape based on the shape of the holding member when the photomask is held in an exposure apparatus on the substrate surface shape data B to obtain transfer surface shape data C When,
On the stage of the inspection apparatus, with the main surface facing up, with the photomask mounted, measuring the height distribution of the main surface to obtain inspection height distribution data I;
Using the inspection height distribution data I and the transfer surface shape data C, obtaining inspection difference data J;
A step of calculating a coordinate deviation amount K at a plurality of points on the main surface corresponding to the inspection difference data J to obtain inspection coordinate deviation amount data K;
A photomask inspection method comprising a step of inspecting the transfer pattern using the inspection coordinate deviation amount data K and the pattern coordinate data L.

(Configuration 12)
12. The photomask inspection method according to Configuration 11, wherein a finite element method is used in the step of obtaining the transfer surface shape data C.

(Configuration 13)
The transfer pattern inspection is performed by using the corrected design data M and the pattern coordinate data L obtained by reflecting the inspection coordinate deviation amount data K in the pattern design data A. The photomask inspection method according to any one of Configurations 10 to 12.

(Configuration 14)
The inspection of the transfer pattern is performed by using the corrected coordinate data N and the pattern design data A obtained by reflecting the inspection coordinate deviation amount data K in the pattern coordinate data L. The photomask inspection method according to any one of Configurations 10 to 12.

(Configuration 15)
In a photomask blank, in which a thin film and a photoresist film are formed on a main surface, a photomask is formed by patterning the thin film.
A photomask manufacturing method comprising the photomask inspection method according to any one of Configurations 10 to 14.

(Configuration 16)
In a method for manufacturing a display device, including performing pattern transfer on a device substrate having a layer to be processed by exposing a photomask having a transfer pattern formed on a main surface,
A method for manufacturing a display device, comprising using a photomask manufactured by the manufacturing method according to any one of configurations 1 to 7.

(Configuration 17)
A method for manufacturing a display device, comprising: sequentially using a plurality of photomasks each having a transfer pattern formed on each main surface and an exposure apparatus, and sequentially transferring a pattern to a plurality of layers to be formed on a device substrate. In
The method for manufacturing a display device, wherein the plurality of photomasks are manufactured by the manufacturing method according to any one of configurations 1 to 7.

(Configuration 18)
A photomask inspection apparatus for inspecting a photomask having a transfer pattern formed by patterning a thin film on a main surface of a substrate,
Coordinate measurement of the pattern formed on the main surface to obtain pattern coordinate data L, coordinate measurement means,
With the main surface facing up, with the photomask placed on the stage, measure the height distribution of the main surface, and obtain height distribution data I during inspection, height measuring means,
Input means for inputting transfer surface shape data C indicating the main surface shape of the substrate in a state where the substrate is held in an exposure apparatus;
Using the height distribution data I at the time of inspection and the transfer surface shape data C, calculation means for calculating the coordinate deviation amount data K for inspection at a plurality of points on the main surface;
A photomask inspection apparatus having inspection means for inspecting the photomask transfer pattern using the inspection coordinate deviation amount data K and the pattern design data A.

(Configuration 19)
A photomask inspection apparatus for inspecting a photomask having a transfer pattern formed by patterning a thin film on a main surface of a substrate,
Coordinate measurement of the pattern formed on the main surface to obtain pattern coordinate data L, coordinate measurement means,
With the main surface facing up, with the photomask placed on the stage, measure the height distribution of the main surface, and obtain height distribution data I during inspection, height measuring means,
Substrate surface shape data B indicating the shape of the main surface of the substrate,
Input means for inputting information on a holding state when holding the substrate in an exposure apparatus, and substrate physical property information including physical property values of the substrate material;
Using the substrate surface shape data B, the information on the holding state, and the substrate physical property information, the transfer surface shape data C indicating the main surface shape of the substrate held in an exposure apparatus is calculated, Using the height distribution data I at the time of inspection and the transfer surface shape data C, calculation means for calculating the coordinate deviation amount data K for inspection at a plurality of points on the main surface;
A photomask inspection apparatus having inspection means for inspecting the photomask transfer pattern using the inspection coordinate deviation amount data K and the pattern design data A.

  According to the present invention, a photomask manufacturing method, a drawing apparatus, a photomask inspection method, a photomask inspection apparatus, and a display apparatus manufacturing method capable of increasing the coordinate accuracy of a pattern formed on a transfer target Can be provided.

FIG. 1 (a) is a side view of the substrate held so that the main surface is vertical, and FIG. 1 (b) is a front view of the substrate. FIG. 2 (a) is a cross-sectional view of a substrate on which a plurality of measurement points are set, and FIG. 2 (b) is a front view of the substrate. FIG. 3 (a) is a cross-sectional view of a mask model used in the finite element method, and FIG. 3 (b) is a front view of the mask model. 4 (a) is a cross-sectional view of the mask model arranged so that the film surface is on the upper side, and FIG. 4 (b) is a cross-sectional view of the mask model arranged so that the film surface is on the lower side. FIG. 4 (c) is a front view of the mask model arranged so that the film surface is on the upper side, and FIG. 4 (d) is a front view of the mask model arranged so that the film surface is on the lower side. is there. FIG. 5 (a) is a cross-sectional view of the mask model at the holding position by the holding member. FIG. 5 (b) is a front view of the mask model, and the holding position by the holding member is indicated by a dotted line. FIG. 6A is a cross-sectional view showing an example of the force exerted on the mask held in the exposure apparatus. FIG. 6B is a diagram illustrating an example of a region where a vacuum pressure is applied to the mask and a holding position of the holding member. It is a schematic diagram of the hexahedron which comprises a mask model. After obtaining the transfer surface shape data C from the substrate surface shape data B, the drawing difference data F is obtained from the difference between the drawing height distribution data E and the transfer surface shape data C, and then the drawing coordinates are drawn from the drawing difference data F. FIG. 6 is a schematic diagram showing a process until obtaining deviation amount data G. It is a schematic diagram for calculating the relationship between the shape variation of the film surface and the resulting coordinate shift. FIG. 5 is a schematic diagram showing a process from obtaining inspection difference data J based on a difference between inspection height distribution data I and transfer surface shape data C to obtaining inspection coordinate deviation amount data K from inspection difference data J. It is a conceptual diagram of the drawing apparatus used with the manufacturing method of the photomask concerning embodiment. FIGS. 12A and 12C show the coordinate measurement results of the pattern drawn on the test photomask. FIGS. 12 (b) and 12 (d) show the results of simulation of coordinate deviation in a state where the test photomask is set in the exposure apparatus. It is the figure which expressed the coordinate shift of the measurement point resulting from the difference in height with a vector.

<Embodiment 1>
The photomask manufacturing method of the present invention includes the following steps.

Preparation of Photomask Blank In the present invention, a photomask is formed by forming a pattern designed based on a device to be obtained on a photomask blank in which one or a plurality of thin films and a photoresist film are formed on the main surface of the substrate. Draws for impersonation. Therefore, a photomask blank in which the thin film and the photoresist film are formed on one main surface of the substrate is prepared.

A known photomask blank can be used.
A transparent substrate such as quartz glass can be used as the substrate. There is no limitation on the size and thickness, but as a device used for manufacturing a display device, one having a side of 300 mm to 1800 mm and a thickness of about 5 to 15 mm can be used.

  In the present application, in addition to a substrate before forming a thin film, a substrate in which one or a plurality of thin films before or after patterning is formed on the main surface, or a substrate in which a photoresist film is formed on the thin film is referred to as “substrate”. (Alternatively, it may be called a photomask blank substrate or a photomask substrate).

  In the step of measuring the flatness and height distribution of the main surface of the substrate, the influence of the thickness of the thin film or the photoresist film formed on the main surface does not substantially occur. This is because the thickness of the thin film or the photoresist film is sufficiently small and does not substantially affect the measurement.

  As a thin film, in addition to a light-shielding film (optical density OD 3 or higher) that blocks exposure light when using a photomask, a semi-transparent film (exposure light transmittance is 2 to 80) that partially transmits exposure light. %), Or a phase shift film (for example, a phase shift amount of exposure light of 150 to 210 degrees, exposure light transmittance of about 2 to 30%), or control of light reflectivity An optical film such as an antireflection film may be used. Furthermore, a functional film such as an etching stopper film may be included. A single film or a laminate of a plurality of films may be used. For example, a light shielding film or an antireflection film containing Cr, a semi-transparent film or a phase shift film containing a Cr compound or metal silicide, and the like can be applied. A photomask blank in which a plurality of thin films are stacked can also be applied. By applying the method of the present invention to the patterning of each of the plurality of thin films, a photomask having excellent coordinate accuracy transferability can be obtained.

  The photoresist formed on the outermost surface may be a positive type or a negative type. A positive type is useful as a photomask for a display device.

I Process for Preparing Pattern Design Data A Pattern design data is transfer pattern data designed based on the device (display device or the like) to be obtained.

  There is no limit to the use of the device manufactured by the photomask according to the present invention. For example, an excellent effect can be obtained by applying the present invention to each layer of each component constituting a liquid crystal display device or an organic EL display device. For example, a line-and-space pattern with a pitch of less than 7 μm (such as a line or space with a CD (Critical Dimension) of 4 μm or a portion with a size of less than 3 μm) or a diameter of 1.5 to 5 μm, especially 1.5 to 3.5 μm The present invention is advantageously used for a photomask for a finely designed display device having a hole pattern or the like.

  If the pattern design data is used as it is without correction, the shape of the film surface at the time of drawing (when placed in the drawing apparatus) and at the time of exposure (when held in the exposure apparatus) Due to the difference, the coordinate accuracy is insufficient when the transfer pattern is formed on the transfer target. For this reason, correction by the following steps is performed.

II Step of Obtaining Transfer Surface Shape Data C Transfer surface shape data C indicating the amount of deformation of the film surface that occurs when the photomask is held in the exposure apparatus and supported. Specifically, it can be performed as follows.

II-1 Step of Obtaining Substrate Surface Shape Data B Substrate surface shape data B is obtained by measuring the flatness of the main surface (film surface side).
For example, the substrate to be measured can be measured by a flatness measuring machine in a state where the main surface is held substantially vertical and the deflection due to its own weight does not substantially affect the main surface shape (see FIG. 1).
The measurement can be performed by a flatness measuring machine using an optical measurement method such as detecting reflected light of irradiated light (laser or the like). Examples of the measuring apparatus include a flatness measuring machine FTT series manufactured by Kuroda Seiko Co., Ltd., and those described in JP-A-2007-46946.
At this time, multiple intersections (lattice points) of grids drawn in the XY direction are set on the main surface at equal intervals (separation distance is set as pitch P) and used as measurement points. (See Fig. 2).

  For example, using a substantially vertical plane as a reference plane, flatness measurement has a function to measure the distance in the Z direction (see Fig. 2) between this reference plane and each of the above measurement points. You can use the machine. By this measurement, the flatness of the main surface of the substrate can be grasped, whereby the substrate surface shape data B is obtained. FIG. 2 shows an example in which P is 10 mm.

  As shown in FIG. 2 (a), the height in the Z direction at all measurement points on the main surface is measured. Thereby, the substrate surface shape data B is obtained in the form of a flatness map (see FIG. 8 (a)).

  When acquiring the substrate surface shape data B, the same measurement is performed by setting measurement points at positions corresponding to the film surface side on the back surface side of the substrate (surface opposite to the main surface serving as the film surface). By performing the above, it is possible to obtain the substrate back surface shape data and the distribution of the substrate thickness (distance between the film surface and the back surface) at each measurement point. The thickness distribution of the substrate is also expressed as TTV (Total thickness variation). This data can be used later.

  Regarding the setting of the measurement point, the separation distance P can be determined from the viewpoint of measurement time depending on the size of the substrate and the viewpoint of correction accuracy. The separation distance P can be, for example, 2 ≦ P ≦ 20 (mm), more preferably 5 ≦ P ≦ 15 (mm).

  In addition, after the surface flatness measurement on the film surface side is performed, the least square plane can be obtained from the measured value. The center of this surface is the origin O.

II-2 Step of Obtaining Transfer Surface Shape Data C Next, consider a state where the photomask is held in the exposure apparatus when the substrate becomes a photomask. The photomask set in the exposure apparatus is held with the film surface facing downward. In this state, the film surface (transfer surface) of the substrate receives a different force depending on the holding state, and its shape changes. For example, the force received by the photomask varies depending on the shape of the holding member. Furthermore, in order to counteract the photomask's own weight and reduce the deflection of the photomask transfer surface, a predetermined region is set on the back surface of the photomask (surface opposite to the film surface side), and the region is subjected to vacuum pressure. When a force is applied (FIG. 6b)), the force received by the photomask varies depending on the area and the vacuum pressure. Here, the case where the vacuum pressure is applied refers to a state in which the photomask is sucked upward by reducing the space on the back surface of the photomask transfer surface.

  The substrate surface shape (transfer surface shape) under such a force can be measured. That is, by providing the required number of measurement points on the film surface of the photomask set in the exposure machine and measuring the surface shape at the measurement points by optical means or the like, for example, as shown in FIG. A map like this can be obtained.

  However, the present invention can be implemented without measuring the shape of the transfer surface. For example, the displacement generated on the photomask film surface held in the exposure apparatus can be calculated and reflected on the substrate surface shape data B to obtain transfer surface shape data C (FIG. 8 (( (See b)) That is, information on the holding state that affects the main plane shape when the photomask is held in the exposure apparatus (the holding condition by the holding member and the vacuum pressure condition against the dead weight are included) ), The transfer surface shape data C can be obtained by simulation.

  In this step, it is preferable to apply the finite element method. Therefore, as a preparation stage, a mask model is created (Figure 3).

  By measuring the flatness of the film surface side and the back surface side as described above, substrate surface shape data of both surfaces is obtained. Here, with respect to the outermost measurement point, one additional virtual measurement point is added at a position separated by one pitch on the substrate end side, and the height of the virtual measurement point in the Z direction is set to the outermost measurement point. Set to the same height as the measurement point. This is to correctly reflect the size and weight of the substrate in the finite element method used below. In addition, a virtual measurement point is set between the corresponding measurement points on the film surface side and the back surface side, and the median value of the two corresponding measurement values is set. Then, adjacent measurement points (including virtual measurement points) are connected with a straight line (see FIGS. 3A and 3B).

  The virtual measurement point is not limited to being provided at the center of the measured values on the film surface and the back surface, and may be provided at two or three points at equal intervals in the thickness direction.

  4A to 4D are schematic views of the mask model as seen from the front and back surfaces and the cross section.

  Next, in this mask model, a plurality of holding points at which the photomask is held by the holding member in the exposure apparatus are set. This is the point that when the photomask is mounted in the exposure apparatus, it is held or restrained by the holding member or by suction, and varies depending on the manufacturer, generation, and size of the exposure apparatus. Determine based on.

In this aspect, as an example, a rectangular belt-shaped holding member arranged in the vicinity of the four sides forming the outer periphery of the main surface of the substrate in parallel with the four sides and spaced from the outer periphery by a predetermined distance, A case of contacting the film surface side of the substrate so as to surround is described (dotted line in FIG. 5 (b)).
That is, in the models shown in FIGS. 6 (a) and 6 (b), a measurement point on the dotted line is set as a holding point. In the exposure apparatus, the holding point comes into contact with the holding member and is displaced to be displaced, and thereby the entire film surface shape may be displaced due to the physical properties of the substrate.
Furthermore, as described above, the substrate is subjected to its own weight and is bent, and thus an upward force is applied to reduce the deflection. This is performed by applying a vacuum pressure from the top (back side) of the substrate. (Fig. 6 (a)). The region that exerts the vacuum pressure can be a rectangular region including the center of the substrate main surface, as shown in FIG. 6 (b).

  In the model shown in FIG. 5 (a), the amount of forced displacement is set so that the position of the measurement point that is the holding point is zero on the Z-axis. Note that the zero position in the Z-axis direction refers to the already set least square plane (and the origin above it). For example, if the value of flatness on the film surface side at a certain measurement point that is a holding point is 5 μm, the forced displacement amount at that measurement point is “−5 μm”.

Further, the amount of vacuum pressure applied from the back side of the substrate is set to an amount that minimizes the flatness of the film surface.
It should be noted that when evaluating the flatness of a predetermined surface, the maximum value of the distance between the surface and a reference surface (a surface substantially parallel to the predetermined surface is often used as the reference surface) Sometimes expressed as a difference in minimum values. That is, when the numerical value of flatness is small, it means that the surface has less irregularities and is flatter.
Therefore, in order to determine the amount of vacuum pressure applied to the simulation, it is only necessary to obtain the vacuum pressure at which the flatness of the film surface is minimized when the vacuum pressure applied to the back surface of the photomask substrate is changed. In general, since the displacement due to the deflection of the substrate due to its own weight is the maximum near the center of the substrate, the distance from the reference surface at the center point of the film surface (substrate main surface) is the distance from the reference surface at the outer edge of the substrate, When closest, the flatness is considered minimal. In the measurement of the distance from the reference plane at the outer edge of the substrate, a plurality of measurement points may be set on the outer edge, or a specific position may be set as a representative point. Further, the vacuum pressure when the film surface flatness is minimized may be actually measured by setting the substrate on the exposure apparatus, or may be obtained as part of the simulation using the information on the holding state. .

  Next, the model conditions prepared above are input to finite element method (FEM) software, and the displacement of each measurement point other than the holding point is calculated by the forced displacement. As a result, “transfer surface shape data C” indicating the film surface shape of the photomask in the exposure apparatus is obtained.

When the finite element method is applied, various physical property values and condition parameters are required. In this embodiment, the following is taken as an example.
[Substrate (quartz glass) property value conditions]
Young's modulus E: 7341 kg / mm ²
Poisson's ratio ν: 0.17
Weight density m: 0.0000022 kg / mm ³
[Mask Model condition]
Coordinate value (x, y, z) file for each measurement point: (For all measurement points on the film surface, back surface, and intermediate points)
Condition file connecting measurement points: Hexahedron In this mode, a model in which hexahedrons are accumulated by connecting all adjacent points with respect to the corresponding measurement points on the film surface and the back surface and their intermediate points (including virtual measurement points). (See FIG. 7).
[Retention condition]
File with forced displacement set: Forced displacement at the above holding point [Vacuum pressure condition]
A file that sets the amount of vacuum pressure and the area that affects it

Then, displacement amounts of all measurement points other than the holding point are calculated by the finite element method.
The photomask held in the exposure apparatus is stationary due to a balance of forces acting on the photomask. At this time,
Self-weight vector G − Stress vector σ − Vacuum pressure vector = 0
Is established.

here,
Stress vector σ = [k] × displacement vector u
(However, [k] is a matrix composed of Young's modulus e and Poisson's ratio ν)
Self-weight vector G = element volume × weight density m × gravity direction vector.

Here, each element is an individual hexahedron as shown in FIG.
When all the elements (the whole board) are overlapped,
G1−σ1−F1 + G2−σ2−F2 + G3−σ3−F3 + ・ ・ ・ = 0
G1-F1 + G2-F2 + G3-F3 + ... = σ1 + σ2 + σ3 + ... = [k1] u1 + [k2] u2 + [k3] u3 + ...

  Here, the displacement amount vector (u1, u2, u3,...) Is a displacement amount at each measurement point and is a numerical value to be obtained. However, the displacement vector at the holding point is input as the forced displacement amount as described above.

  Data on the film surface shape of the photomask held in the exposure apparatus can be obtained from the displacement vector of each measurement point calculated by the finite element method. That is, this is data of the film surface shape of the photomask when pattern transfer is performed by the exposure apparatus, and is “transfer surface shape data C”.

III Step of Obtaining Height Distribution Data E During Drawing FIG. 11 is a conceptual diagram of a drawing apparatus used in the photomask manufacturing method according to the embodiment of the present invention. This drawing apparatus has at least a stage 10, drawing means 11, height measuring means 12, and drawing data creating means 15 (calculation means). A photomask blank 13 is fixed on the stage 10. A thin film 14 is formed on one side of the photomask blank, and the surface on which the thin film 14 is formed is arranged upward. The drawing means 11 irradiates an energy beam such as a laser, for example, and draws a predetermined transfer pattern on the photomask blank 13 with a photoresist film fixed on the stage 10 in the drawing process. The height measuring means 12 is arranged at a certain distance from the surface of the photomask blank 13 by, for example, an air cushion. The height measuring means 12 is a mechanism that increases and decreases according to a change in height due to the surface shape of the photomask blank 13, and measures the height (Z direction) of the main surface of the photomask blank 13. be able to.

  As a method of measuring the height of the surface, in addition to the above, a method of measuring using an air flow rate for maintaining a member similar to the height measuring means 12 at a fixed position, and a capacitance between the gaps. A measurement method, a pulse count using a laser, an optical focus method, and the like can be used and are not limited.

  A photomask blank is placed on the stage of such a drawing apparatus with the main surface (film surface side) on the upper side, and the height of the film surface is measured at the measurement point (separation distance P) set above. A map of this is the height distribution data E at the time of drawing shown in FIG.

The factor of deformation of this height distribution from the ideal plane is as described above,
(1) Unevenness on stage surface (2) Deflection of substrate due to foreign object pinching on stage,
(3) Unevenness on the film surface of the photomask blank (4) Unevenness on the film surface due to the unevenness on the back surface of the photomask blank is considered to have accumulated. Then, drawing is performed on the film surface of the photomask blank in this state.

IV Step of Obtaining Drawing Difference Data F Next, drawing difference data F is obtained using the obtained drawing height distribution data E and the transfer surface shape data C obtained previously. In this embodiment, the difference between the height distribution data E during drawing and the transfer surface shape data C is obtained. This is the difference between the film surface shape of the photomask blank at the time of drawing and the film surface shape of the photomask at the time of exposure. This is the drawing difference data F (see FIG. 8D).

The deformation factor from the ideal plane of the film surface of the photomask held in the exposure apparatus is
(5) Unevenness on the film surface of the photomask (substantially the same as (3) above)
(6) Deformation of the film surface forced by being held by the photomask holding member (7) Deflection due to its own weight and deformation in the reverse direction due to vacuum pressure to reduce this are accumulated.

  Therefore, it can be said that the difference between the two film surface shapes is an element that causes a coordinate shift due to transfer, and should be applied to the correction of the “pattern design data A”. This is the drawing difference data F.

Step of obtaining V drawing coordinate deviation amount data G The drawing difference data F is converted into displacement (coordinate deviation amount) on the XY coordinates. For example, it can be converted by the following method (see FIG. 9).

  FIG. 9 is an enlarged view of a cross section of the substrate 13 on the stage 10 of the drawing apparatus. The thin film 14 is omitted. The shape of the surface 20 of the substrate 13 disposed on the stage 10 is deformed from the ideal plane due to a plurality of factors as described above.

In the height distribution data E at the time of drawing, when the height at the measurement point adjacent to the measurement point of 0 height (that is, the measurement point whose height coincides with the reference surface 21) is H, due to the difference in height. The angle Φ formed by the surface 20 of the substrate 13 and the reference surface 21 is
sinΦ = H / Pitch (1)
(Pitch: Distance between measurement points, that is, distance P between adjacent measurement points)
It is represented by In the above, H / Pitch can be considered as a gradient in the height direction of the substrate surface.

If the value of Φ is sufficiently small,
Φ = H / Pitch (Equation 1 ')
Can also be approximated. In the following description, (Formula 1) is used.

In the above case, the deviation d in the X-axis direction of the measurement point due to the difference in height is
d = sinΦ × t / 2 = H × (t / 2Pitch) (Equation 2)
Can be obtained.

Also in the above, if Φ is sufficiently small,
d = Φ × t / 2 = H × (t / 2Pitch) (Formula 2 ′)
Can also be approximated.
Alternatively, the coordinate shift amount of the measurement point due to the difference in height can be calculated by a technique using a vector. FIG. 13 is a diagram in which a coordinate shift of a measurement point due to a difference in height is expressed by a vector. In the height distribution data E at the time of drawing, consider an inclined surface formed from arbitrary three measurement points. At this time, the deviation ΔX between the inclined surface and the X-axis direction and the deviation ΔY between the inclined surface and the Y-axis direction are expressed by the following equations.
ΔX = t / 2 × cosθx
ΔY = t / 2 × cosθy (Equation 3)
Two gradient vectors can be created from arbitrary three measurement points. A normal vector for the inclined plane is created from the outer product calculation of the two inclined vectors.
Further, cos θx is calculated from the inner product calculation of the normal vector and the X-axis unit vector, and cos θy is calculated from the inner product calculation of the normal vector and the Y-axis unit vector.
By substituting the calculated cos θx and cos θy into (Equation 3), the deviation ΔX in the X-axis direction and the deviation ΔY in the Y-axis direction can be finally calculated.

  Here, t is the thickness of the substrate. The thickness t of each measurement point is included in the TTV already acquired above. Here, the average value of the thickness of the substrate may be used without using the TTV value.

  Therefore, in this embodiment, the height corresponding to the difference between the transfer surface shape data C and the drawing height distribution data E is obtained for all the measurement points on the substrate 13, and the obtained drawing difference data F is compared with X. By calculating the coordinate shift amount in the direction and the Y direction, the drawing coordinate shift amount data G can be obtained. Of course, the calculation method is not limited to the above.

VI Drawing Step for Drawing Correction Pattern Data H Using the drawing coordinate deviation amount data G obtained above and “pattern design data A”, the correction pattern data H is drawn.
At this time, the pattern design data A may be corrected based on the drawing coordinate deviation amount data G, drawing correction pattern data H (not shown) may be obtained, and drawing may be performed based on the drawing correction pattern data H.

  When correcting the pattern design data A, the drawing coordinate deviation amount data G obtained for each measurement point may be processed and used. For example, the drawing coordinate deviation amount data G may be reflected in the pattern design data A after interpolation of data for each measurement point using the least square method or normalization by a predetermined rule.

Alternatively, the coordinate system of the drawing apparatus may be corrected based on the drawing coordinate deviation amount data G, and drawing may be performed using the obtained corrected coordinate system and the “pattern design data A”. This is because many drawing apparatuses have a drawing function based on the corrected coordinate system after performing a predetermined correction on the coordinate system of the drawing apparatus.
The drawing coordinate deviation amount data G used at this time can also be processed in the same manner as described above.

Note that the drawing method according to the present invention is not limited to the above embodiment.
When drawing, a mark pattern or the like may be appropriately added outside the transfer pattern area. As will be described later, a coordinate measurement mark pattern can be added and drawn here.

  For example, the shape of the holding member of the exposure apparatus may vary depending on the apparatus as described above. In exposure apparatuses having different mechanisms, the model conditions, the holding conditions, and the vacuum pressure conditions at the time of calculation of the finite element method described above may be appropriately changed.

  In the above aspect, the holding point at which the photomask is held by the holding member is constrained on a plane (the least square plane of the substrate film surface). This is because the holding member holds the photomask in a single plane. However, if the holding point does not lie on a single plane due to the shape of the holding member, the shape of the holding member may be reflected when setting the forced displacement amount in the step of obtaining the transfer surface shape data C. .

  Further, the order of the steps may be changed as long as the effects of the present invention are not hindered.

  After the pattern data corrected on the photomask blank is drawn by the drawing method of the above aspect, a photomask is manufactured by a patterning process.

Patterning Process The photomask blank (photomask intermediate) on which drawing has been performed becomes a photomask through the following steps.
A known method can be applied to the patterning process. That is, the drawn resist film is developed with a known developer to form a resist pattern. Using this resist pattern as an etching mask, the thin film can be etched.
A known etching method can be used. Either dry etching or wet etching may be applied. Since the present invention is particularly useful as a method for manufacturing a photomask for a display device, the effects of the present invention are remarkably obtained when wet etching is applied.

  Note that, in the drawing process of the present invention described above, the object to be drawn is not only a photomask blank (transfer pattern is not drawn) but also a plurality of thin films, and a part thereof It may be a photomask intermediate in which a pattern is formed.

  For the photomask blank provided with a plurality of thin films, the above-described drawing process of the present invention can be applied to the drawing process for patterning each thin film. In this case, it is extremely advantageous in that a high-precision photomask having excellent overlay accuracy can be manufactured.

Drawing Device In addition, this application includes the invention regarding the drawing device which can implement the above drawing methods.
That is, the drawing apparatus is a drawing apparatus used for drawing a transfer pattern on a photomask blank in which a thin film and a photoresist film are formed on the main surface of a substrate.
The drawing apparatus includes the following means.

Height measuring means The height measuring means measures the height distribution of the main surface in a state where the photomask blank is placed on the stage with the main surface facing upward, and obtains height distribution data E during drawing It is a means that can.

Input means Input means
It is means for enabling input of pattern design data A for the transfer pattern and transfer surface shape data C indicating the main surface shape of the substrate in a state where the substrate is held in an exposure apparatus.

Calculation means The calculation means calculates drawing coordinate deviation amount data G at a plurality of points on the main surface using the drawing height distribution data E and the transfer surface shape data C.

  The drawing apparatus includes drawing means for drawing on the photomask blank using the drawing coordinate deviation amount data G and the pattern design data A.

Furthermore, the drawing apparatus of this aspect may include the following means in addition to the height measuring means.
Input means Input means
Pattern design data A for the transfer pattern,
Substrate surface shape data B indicating the shape of the main surface of the substrate,
Information on a holding state when holding the substrate in an exposure apparatus, and substrate physical property information including physical property values of the substrate material,
Is a means for enabling the input.

Arithmetic means The arithmetic means uses the substrate surface shape data B, the information on the holding state, and the substrate physical property information to indicate the main surface shape of the substrate held in the exposure apparatus. Means capable of calculating data C and calculating drawing coordinate deviation amount data G at a plurality of points on the main surface using the drawing height distribution data E and the transfer surface shape data C It is.
As the calculation means, for example, a known calculation device such as a personal computer can be used.

Drawing means The drawing means is means capable of drawing on the photomask blank using the drawing coordinate deviation amount data G and the pattern design data A.

  In addition, it is preferable to provide a control means for controlling the input means, calculation means, and drawing means.

  Here, the information on the holding state is, for example, holding conditions (the shape of the holding member or the coordinates of the substrate holding point at which the substrate contacts the holding member when the substrate is held in the exposure apparatus (according to the coordinate information). The forced displacement amount of the holding point can be calculated), and it is preferable that the vacuum pressure condition (the amount of the vacuum pressure and the region to which it is given) is included.

  The substrate property information can be, for example, the Young's modulus, Poisson's ratio, and weight density of the substrate.

  By using such a drawing apparatus, the drawing process necessary for the photomask manufacturing method described above can be performed.

<Embodiment 2 (inspection)>
As described above, according to the present invention, it is possible to obtain a photomask capable of extremely increasing the coordinate accuracy of a pattern formed on a workpiece.
By the way, when inspecting such a photomask before shipment, it is possible to perform an inspection in consideration of the difference between the photomask placed on the inspection apparatus and the photomask held on the exposure apparatus. Most desirable.
Thus, the inventors have found a need for a new inspection method.

VII Step for Obtaining Pattern Coordinate Data L The photomask on which pattern formation has been performed is placed on the stage of the coordinate inspection apparatus with the film surface (pattern formation surface) facing upward, and coordinate measurement is performed. The data obtained here is referred to as pattern coordinate data L.
Here, the coordinate measurement is preferably performed by measuring the coordinates of the mark pattern formed on the main surface of the photomask at the same time as the transfer pattern. This mark pattern is preferably provided at a plurality of positions on the main surface and outside the region of the transfer pattern.

VIII Step of Obtaining Transfer Surface Shape Data C On the other hand, transfer surface shape data C indicating the amount of deformation of the main surface caused by holding this photomask in the exposure apparatus is obtained. This is the same as the steps II-1 to II-2 described above.
In the case of the photomask of the present invention manufactured by applying the above drawing method, the transfer surface shape data C already obtained can be used.

IX Process of obtaining height distribution data I during inspection With the photomask placed on the stage of the inspection apparatus with the film surface (pattern formation surface) facing up, the height distribution of the main surface is measured. Thus, the height distribution data I at the time of inspection is obtained.
The height measurement in this step is the same as the height measurement performed in “Process for obtaining height distribution data E at the time of drawing” in III above. In this step, it is preferable to measure the height at the same measurement point as the height measurement in step III.

X Step of Obtaining Inspection Difference Data J By obtaining the difference between the height distribution data I during inspection and the transfer surface shape data C, the inspection difference data J is obtained (see FIGS. 10A to 10D).

XI Step for Obtaining Inspection Coordinate Deviation Data K Calculate coordinate deviation amounts at a plurality of points on the main surface corresponding to the inspection difference data J to obtain inspection coordinate deviation data K (FIG. 10 (d)). ) To (e)). Here, the step of converting the height difference into the coordinate shift amount can be performed in the same manner as the step V described above.

Then, the transfer pattern inspection is performed using the obtained inspection coordinate deviation amount data K and the pattern coordinate data L.
Specifically, in the inspection of the transfer pattern, the inspection coordinate deviation amount data K is reflected in the pattern design data A, and the obtained correction design data M and the pattern coordinate data L are used (compared). Can do).
Alternatively, in the inspection of the transfer pattern, the inspection coordinate deviation amount data K is reflected in the pattern coordinate data L, and the obtained correction coordinate data N and the pattern design data A are used (compared). You can also do it.

  It is preferable to inspect the photomask manufactured by the manufacturing method of the present invention by the inspection method of the present invention.

In addition, there is no restriction | limiting in the use of a photomask, and there is no restriction | limiting also in the structure.
It is clear that the operational effects of the present invention can be obtained in any photomask having any film configuration such as a so-called binary mask, multi-tone mask, and phase shift mask.

Inspection Device The present invention includes an invention related to an inspection device capable of performing the above inspection method.
That is,
A photomask inspection apparatus for inspecting a photomask having a transfer pattern formed by patterning a thin film on a main surface of a substrate,
Coordinate measurement of the pattern formed on the main surface to obtain pattern coordinate data L, coordinate measurement means,
With the main surface facing up, with the photomask placed on the stage, measure the height distribution of the main surface, and obtain height distribution data I during inspection, height measuring means,
Input means for inputting transfer surface shape data C indicating the main surface shape of the substrate in a state where the substrate is held in an exposure apparatus;
Using the height distribution data I at the time of inspection and the transfer surface shape data C, calculation means for calculating the coordinate deviation amount data K for inspection at a plurality of points on the main surface;
A photomask inspection apparatus having inspection means for inspecting the photomask transfer pattern using the inspection coordinate deviation amount data K and the pattern design data A.

Furthermore, the present invention includes the following inspection apparatus.
A photomask inspection apparatus for inspecting a photomask having a transfer pattern formed by patterning a thin film on a main surface of a substrate,
Coordinate measurement of the pattern formed on the main surface to obtain pattern coordinate data L, coordinate measurement means,
With the main surface facing up, with the photomask placed on the stage, measure the height distribution of the main surface, and obtain height distribution data I during inspection, height measuring means,
Substrate surface shape data B indicating the shape of the main surface of the substrate,
Input means for inputting information on a holding state when holding the substrate in an exposure apparatus, and substrate physical property information including physical property values of the substrate material;
Using the substrate surface shape data B, the information on the holding state, and the substrate physical property information, the transfer surface shape data C indicating the main surface shape of the substrate held in an exposure apparatus is calculated, Using the height distribution data I at the time of inspection and the transfer surface shape data C, calculation means for calculating the coordinate deviation amount data K for inspection at a plurality of points on the main surface;
An inspection apparatus having inspection means for inspecting the transfer pattern of the photomask using the inspection coordinate deviation amount data K and the pattern design data A.

  The information regarding the holding state and the substrate physical property information including the physical property values of the substrate material when the substrate is held in the exposure apparatus are as described above.

  Calculating the transfer surface shape data C, which indicates the main surface shape of the substrate held in the exposure apparatus, means an operation for performing the same steps as the steps II-1 to II-2 described above. To do.

  When inspecting the transfer pattern of the photomask using the inspection coordinate deviation amount data K and the pattern design data A, a comparison necessary for the step XI (for comparison if necessary) (Calculation).

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a display device, including performing pattern transfer on a device substrate having a layer to be processed by exposing a photomask having a transfer pattern formed on a main surface thereof. And a manufacturing method of a display device using a photomask according to the manufacturing method of the present invention.

  That is, using the photomask according to the manufacturing method of the present invention, and manufacturing the photomask, the conditions are determined for the state held in the exposure apparatus, and exposure is performed using the exposure apparatus. Pattern transfer A display device manufacturing method to which the method is applied. The pattern transferred to the workpiece by the pattern transfer becomes a display device by being subjected to processing such as etching.

Here, as the optical performance of the exposure apparatus, for example, the effects of the present invention are conspicuous when it is as follows.
It is an exposure device for 1x exposure, used for LCD (or FPD, liquid crystal),
The numerical aperture (NA) of the optical system is 0.08 to 0.15 (especially 0.08 to 0.10),
Coherence factor (σ) is 0.5-0.9,
The exposure wavelength is preferably exposure light having a representative wavelength of any one of i-line, h-line, and g-line, particularly a broad wavelength light source including all i-line, h-line, and g-line.
When the photomask is set in the exposure apparatus, it is preferable to apply the vacuum pressure applied in the finite element method.

  The layer to be processed refers to each layer that becomes a constituent of a desired electronic device through a process such as etching after the transfer pattern of the photomask is transferred. For example, when a TFT (thin film transistor) circuit for driving a liquid crystal display device or an organic EL display device is formed, a pixel layer, a source / drain layer, and the like are exemplified.

  The device substrate refers to a substrate having a circuit that is a component of the electronic device to be obtained, such as a liquid crystal panel substrate or an organic EL panel substrate.

  Furthermore, the present invention uses the exposure apparatus and a plurality of photomasks each having a transfer pattern formed on each main surface, and sequentially performs pattern transfer on a plurality of layers to be processed formed on a device substrate. In the manufacturing method of the display apparatus containing this, using the photomask manufactured by the manufacturing method of this invention is included.

  The display device manufactured by applying the present invention has extremely high overlay accuracy of each layer constituting the display device. Therefore, the display device manufacturing yield is high and the manufacturing efficiency is high.

[Example]
The effect of the invention by the photomask manufacturing method (drawing step) of the present invention will be described with reference to the schematic diagram shown in FIG.
Here, when a transfer pattern is drawn on a substrate (photomask blank) having a specific substrate surface shape (substrate surface shape data B), the coordinate accuracy of the transfer pattern when set in the exposure apparatus is determined. The result of having obtained by simulation whether it will become (resulting in the coordinate precision of the pattern formed on a to-be-transferred body will be shown) is shown.

  First, a specific test pattern was drawn on the photomask blank using a drawing apparatus. The test photomask blank used here had a light shielding film and a positive photoresist film formed on the main surface of a quartz substrate having a size of 850 mm × 1200 mm.

  The pattern design data used here is a test pattern including a cross pattern arranged on the entire main surface at intervals of 75 mm in the X and Y directions. Then, the photoresist was developed, and the light shielding film was wet-etched to obtain a test photomask having a light shielding film pattern. FIG. 12 (a) shows the result of setting this in the coordinate inspection apparatus and performing coordinate measurement.

  Incidentally, here, the stage flatness of the drawing apparatus and the coordinate deviation factor due to the stage flatness of the coordinate inspection apparatus are obtained from the data of FIG. 12 (a) by measuring the stage flatness of both apparatuses in advance. Has been removed.

  Next, a simulation was performed on the coordinate shift in a state where the test photomask was set in an exposure apparatus (equal magnification projection exposure method). Here, using the shape information of the mask holding member of the exposure machine, the vacuum pressure condition, and the substrate physical property information, the coordinate deviation generated in the above test pattern is calculated using the finite element method, and the data in FIG. (Comparative example) was obtained.

  On the other hand, when drawing a similar test pattern on the photomask blank, pattern design data was drawn by correcting the coordinate system of the drawing machine. When correcting the coordinate system, the coordinate deviation amount data for drawing was obtained by the above steps II-1 to V-V. FIG. 12 (c) shows the result of setting the test photomask obtained as a result to the coordinate inspection apparatus and performing coordinate measurement.

  Next, a simulation was performed in the same manner as described above for the coordinate deviation in a state where the test photomask obtained as a result was set in the exposure apparatus. The simulation results are shown in FIG. 12 (d) (Example).

  From FIG. 12 (d), it can be seen that a transfer image closer to the pattern design data can be obtained on the transfer object as compared with FIG. 12 (b). The photomask manufactured by the method of the present invention has high coordinate accuracy, and the coordinate error value can be suppressed to less than 0.15 μm. In other words, it is possible to achieve an accuracy in which error components other than the coordinate deviation due to the drawing apparatus ability are substantially removed.

DESCRIPTION OF SYMBOLS 10 Stage 11 Drawing means 12 Measuring means 13 Photomask blank 14 Thin film 15 Drawing data creation means 20 Surface 21 Reference surface

Claims (19)

In a photomask manufacturing method, comprising preparing a photomask blank in which a thin film and a photoresist film are formed on a main surface of a substrate, and drawing a predetermined transfer pattern by a drawing apparatus.
Preparing pattern design data A based on the design of the predetermined transfer pattern;
A step of obtaining transfer surface shape data C indicating the shape of the main surface when the photomask is held in an exposure apparatus;
On the stage of the drawing apparatus, obtaining the height distribution data E at the time of drawing indicating the height distribution of the main surface in a state where the photomask blank is placed with the main surface facing up,
Using the drawing height distribution data E and the transfer surface shape data C to obtain drawing difference data F;
At a plurality of points on the main surface, calculating a coordinate deviation amount corresponding to the drawing difference data F, and obtaining drawing coordinate deviation amount data G;
Using the drawing coordinate deviation amount data G and the pattern design data A, and having a drawing step of drawing on the photomask blank,
Photomask manufacturing method. In a photomask manufacturing method, comprising preparing a photomask blank in which a thin film and a photoresist film are formed on a main surface of a substrate, and drawing a predetermined transfer pattern by a drawing apparatus.
Preparing pattern design data A based on the design of the predetermined transfer pattern;
A step of preparing substrate surface shape data B obtained by measuring the surface shape of the main surface,
A step of reflecting the displacement generated in the surface shape based on the shape of the holding member when the photomask is held in an exposure apparatus on the substrate surface shape data B to obtain transfer surface shape data C When,
On the stage of the drawing apparatus, measuring the height distribution of the main surface in a state where the photomask blank is placed with the main surface facing up, and obtaining height distribution data E during drawing; ,
Using the drawing height distribution data E and the transfer surface shape data C to obtain drawing difference data F;
A step of calculating coordinate deviation amount G at a plurality of points on the main surface corresponding to the drawing difference data F to obtain drawing coordinate deviation amount data G;
A photomask manufacturing method, comprising: a drawing step of drawing on the photomask blank using the drawing coordinate deviation amount data G and the pattern design data A.   3. The photomask manufacturing method according to claim 2, wherein a finite element method is used in the step of obtaining the transfer surface shape data C.   The drawing step is characterized in that drawing is performed using correction pattern data H obtained by correcting the pattern design data A based on the drawing coordinate deviation amount data G. The manufacturing method of the photomask in any one of 1-3.   In the drawing step, the coordinate system of the drawing apparatus is corrected based on the drawing coordinate deviation amount data G, and drawing is performed using the obtained corrected coordinate system and the pattern design data A. The manufacturing method of the photomask in any one of Claims 1-3.   6. The photomask according to claim 1, wherein a plurality of holding points held by a holding member are arranged on a plane when the photomask is held in an exposure apparatus. Manufacturing method.   The substrate surface shape data B is the position of a plurality of measurement points on the main surface in a state where the photomask blank or the substrate for making the photomask blank is held so that the main surface is vertical. The method for producing a photomask according to claim 2, wherein the photomask is obtained by measuring A drawing apparatus used for drawing a transfer pattern on a photomask blank in which a thin film and a photoresist film are formed on a main surface of a substrate,
In the state where the photomask blank is placed on the stage with the main surface facing up, the height distribution of the main surface is measured to obtain drawing height distribution data E,
Input means for inputting pattern design data A of the transfer pattern, and transfer surface shape data C indicating the main surface shape of the substrate in a state where the substrate is held in an exposure apparatus;
Using the drawing height distribution data E and the transfer surface shape data C, calculation means for calculating drawing coordinate deviation amount data G at a plurality of points on the main surface;
A drawing apparatus comprising drawing means for drawing on the photomask blank using the drawing coordinate deviation amount data G and the pattern design data A. A drawing apparatus used for drawing a transfer pattern on a photomask blank in which a thin film and a photoresist film are formed on a main surface of a substrate,
In the state where the photomask blank is placed on the stage with the main surface facing up, the height distribution of the main surface is measured to obtain drawing height distribution data E,
Pattern design data A for the transfer pattern,
Substrate surface shape data B indicating the shape of the main surface of the substrate,
Information about the holding state when holding the substrate in the exposure apparatus;
And input means for inputting substrate physical property information including physical property values of the substrate material,
Using the substrate surface shape data B, the information on the holding state, and the substrate physical property information, the transfer surface shape data C indicating the main surface shape of the substrate held in an exposure apparatus is calculated, Using the drawing height distribution data E and the transfer surface shape data C, calculation means for calculating drawing coordinate deviation amount data G at a plurality of points on the main surface;
A drawing apparatus comprising drawing means for drawing on the photomask blank using the drawing coordinate deviation amount data G and the pattern design data A. In a photomask inspection method for inspecting a photomask having a transfer pattern formed by patterning a thin film on a main surface of a substrate using an inspection apparatus,
In a state where the photomask is placed on the stage of the inspection apparatus, a coordinate measurement of a pattern formed on the main surface is performed to obtain pattern coordinate data L;
A step of obtaining transfer surface shape data C indicating the shape of the main surface when the photomask is held in an exposure apparatus;
On the stage of the inspection apparatus, with the main surface facing up, with the photomask mounted, measuring the height distribution of the main surface to obtain inspection height distribution data I;
Using the inspection height distribution data I and the transfer surface shape data C, obtaining inspection difference data J;
A step of calculating a coordinate deviation amount K at a plurality of points on the main surface corresponding to the inspection difference data J to obtain inspection coordinate deviation amount data K;
A photomask inspection method comprising a step of inspecting the transfer pattern using the inspection coordinate deviation amount data K and the pattern coordinate data L. In a photomask inspection method for inspecting a photomask having a transfer pattern formed by patterning a thin film on a main surface of a substrate using an inspection apparatus,
In a state where the photomask is placed on the stage of the inspection apparatus, a coordinate measurement of a pattern formed on the main surface is performed to obtain pattern coordinate data L;
A step of preparing substrate surface shape data B obtained by measuring the surface shape of the main surface,
A step of reflecting the displacement generated in the surface shape based on the shape of the holding member when the photomask is held in an exposure apparatus on the substrate surface shape data B to obtain transfer surface shape data C When,
On the stage of the inspection apparatus, with the main surface facing up, with the photomask mounted, measuring the height distribution of the main surface to obtain inspection height distribution data I;
Using the inspection height distribution data I and the transfer surface shape data C, obtaining inspection difference data J;
A step of calculating a coordinate deviation amount K at a plurality of points on the main surface corresponding to the inspection difference data J to obtain inspection coordinate deviation amount data K;
A photomask inspection method comprising a step of inspecting the transfer pattern using the inspection coordinate deviation amount data K and the pattern coordinate data L.   12. The photomask inspection method according to claim 11, wherein a finite element method is used in the step of obtaining the transfer surface shape data C.   The transfer pattern inspection is performed by using the corrected design data M and the pattern coordinate data L obtained by reflecting the inspection coordinate deviation amount data K in the pattern design data A. The photomask inspection method according to any one of claims 10 to 12.   The inspection of the transfer pattern is performed by using the corrected coordinate data N and the pattern design data A obtained by reflecting the inspection coordinate deviation amount data K in the pattern coordinate data L. The photomask inspection method according to any one of claims 10 to 12. In a photomask blank, in which a thin film and a photoresist film are formed on a main surface, a photomask is formed by patterning the thin film.
A photomask manufacturing method comprising the photomask inspection method according to claim 10. In a method for manufacturing a display device, including performing pattern transfer on a device substrate having a layer to be processed by exposing a photomask having a transfer pattern formed on a main surface,
A method for manufacturing a display device, wherein the photomask manufactured by the manufacturing method according to claim 1 is used. A method for manufacturing a display device, comprising: sequentially using a plurality of photomasks each having a transfer pattern formed on each main surface and an exposure apparatus, and sequentially transferring a pattern to a plurality of layers to be formed on a device substrate. In
The method for manufacturing a display device, wherein the plurality of photomasks are manufactured by the manufacturing method according to claim 1. A photomask inspection apparatus for inspecting a photomask having a transfer pattern formed by patterning a thin film on a main surface of a substrate,
Coordinate measurement of the pattern formed on the main surface to obtain pattern coordinate data L, coordinate measurement means,
With the main surface facing up, with the photomask placed on the stage, measure the height distribution of the main surface, and obtain height distribution data I during inspection, height measuring means,
Input means for inputting transfer surface shape data C indicating the main surface shape of the substrate in a state where the substrate is held in an exposure apparatus;
Using the height distribution data I at the time of inspection and the transfer surface shape data C, calculation means for calculating the coordinate deviation amount data K for inspection at a plurality of points on the main surface;
A photomask inspection apparatus having inspection means for inspecting the photomask transfer pattern using the inspection coordinate deviation amount data K and the pattern design data A. A photomask inspection apparatus for inspecting a photomask having a transfer pattern formed by patterning a thin film on a main surface of a substrate,
Coordinate measurement of the pattern formed on the main surface to obtain pattern coordinate data L, coordinate measurement means,
With the main surface facing up, with the photomask placed on the stage, measure the height distribution of the main surface, and obtain height distribution data I during inspection, height measuring means,
Substrate surface shape data B indicating the shape of the main surface of the substrate,
Input means for inputting information on a holding state when holding the substrate in an exposure apparatus, and substrate physical property information including physical property values of the substrate material;
Using the substrate surface shape data B, the information on the holding state, and the substrate physical property information, the transfer surface shape data C indicating the main surface shape of the substrate held in an exposure apparatus is calculated, Using the height distribution data I at the time of inspection and the transfer surface shape data C, calculation means for calculating the coordinate deviation amount data K for inspection at a plurality of points on the main surface;
A photomask inspection apparatus having inspection means for inspecting the photomask transfer pattern using the inspection coordinate deviation amount data K and the pattern design data A.