KR20120137279A - Photomask substrate, photomask substrate manufacturing method, photomask manufacturing method and pattern transfer method - Google Patents

Abstract

PURPOSE: A photomask substrate, a photomask substrate manufacturing method, a photomask manufacturing method, and a pattern transferring method are provided to reduce the variation of proximity gaps according to exposure devices. CONSTITUTION: A photomask substrate manufacturing method includes the following steps: gap data and intrinsic gap data are acquired; a proximity gap, which is the distance between a sample mask substrate and a sample glass substrate, is verified; shape processing data is acquired to reduce gap variation caused by an exposure device; a shape process is implemented with respect to a photomask substrate; the photomask is prepared; and a pattern transferring process is implemented. [Reference numerals] (AA) Mask with abnormal surface flatness by intrinsic influence of an exposure device(flatness 0); (BB) Gap data C; (CC) Mask surface shape for gap deviation 0 (gap variation reversion phenomenon); (D1,D2) Gap; (EE) Wide; (FF) Narrow; (GG,NN) Position; (HH) Variation 20-70um; (II) Mask surface displacement; (J1,J2) Convex part; (KK) Concave part; (LL) Space side; (MM) Substrate side; (OO) Panel substrate with abnormal surface flatness by intrinsic influence of an exposure device; (PP) Gap data by removing variation components from an exposure device except for the intrinsic variation(gap data C)

Description

Photomask Substrate, Manufacturing Method of Photomask Substrate, Manufacturing Method of Photomask and Pattern Transfer Method {PHOTOMASK SUBSTRATE, PHOTOMASK SUBSTRATE MANUFACTURING METHOD, PHOTOMASK MANUFACTURING METHOD AND PATTERN TRANSFER METHOD}

TECHNICAL FIELD The present invention relates to a photomask substrate used for a photomask for a liquid crystal display device and the like. In particular, when performing pattern transfer using a proximity exposure apparatus, a photomask substrate for improving the shape precision (line width precision, coordinate accuracy, etc.) of a pattern formed on a transfer object and a photomask using the same It relates to the production of photomask blanks and photomasks, and also to pattern transfer methods.

Patent Document 1 discloses a proximity correction device in which a photomask and a transfer object are placed in close proximity and are exposed, and each of the two sides of the photomask is held as a warpage correction mechanism for reducing warpage due to its own weight. It is described that it has a mask holder to protect and two warpage correction bars which press each edge of the photomask hold | maintained by this mask holder from upper direction (FIG. 1 ( a), (b)).

Patent Document 2 describes a mask holding device for correcting warpage of a photomask in a proximity exposure device. Here, the mask is held by a frame-shaped mask holder almost the same size as the mask, an airtight chamber is formed above the photomask, and the photo is caused by the difference between the air pressure and the external air pressure in the airtight chamber. A method of correcting warpage by floating a photomask to balance its own weight is described (see FIG. 2).

Patent Document 3 discloses such a substrate for the problem that the substrate bends during actual use, in which a large-size photomask substrate is horizontally held in the exposure apparatus, so that the desired flatness is not obtained. A glass substrate for high leveling is described.

[Patent Document 1] Japanese Patent Application Publication No. 2009-260172 [Patent Document 2] Japanese Patent Application Publication No. 2003-131388 [Patent Document 3] Patent No. 4362732

In recent years, in manufacture of display apparatuses, such as a liquid crystal display device, high transfer precision is calculated | required with the improvement of the production efficiency by the enlargement of the photomask to be used. In a liquid crystal display device, a TFT substrate on which a TFT (thin film transistor) array is formed, and a CF (color filter) on which an RGB pattern is formed are bonded, and liquid crystal is enclosed therebetween. It is equipped with a structure. Such a TFT substrate and CF are manufactured by applying a photolithography process using a plurality of photomasks. In recent years, with the advancement of specifications, such as the brightness | luminance, the operation speed, and the like of the liquid crystal display device which is a final product, the pattern of a photomask becomes small and the demand of the line width precision and coordinate precision as a transfer result becomes increasingly strict.

Accordingly, the present invention provides a photomask substrate capable of transferring a fine transfer pattern faithfully to a pattern design value with high accuracy, a photomask blank using the same, a method for producing a photomask, a pattern transfer method using the same, and the like. The purpose is to propose.

The first aspect of the present invention,

A transfer pattern is formed on the main surface, mounted on the proximity exposure apparatus, and exposed by forming a proximity gap between the transfer targets placed on the stage of the proximity exposure apparatus. A photomask substrate for forming a photomask used to transfer the transfer pattern,

In one or a plurality of specific regions on the main surface, the shape processing of the removal amount different from the peripheral region other than the specific region is performed to form a concave shape, a convex shape, or an uneven shape, thereby forming the photomask substrate in the proximity exposure apparatus. Fluctuation due to the position of the proximity gap, which occurs when

The shape processing is a photomask substrate which reduces variations inherent to the proximity exposure apparatus extracted from variations due to the position of the proximity gap.

According to a second aspect of the present invention,

The main surface on which the shape processing is performed is the photomask substrate according to the first embodiment having a correction shape determined based on variations inherent in the extracted proximity exposure apparatus.

In a third aspect of the present invention,

The said shape processing was performed only for the specific area | region which contains the area | region in which the fluctuation | variation intrinsic to the said extracted proximity exposure apparatus exceeded the predetermined | prescribed gap variation tolerance value on the said main surface. It is a photomask substrate as described in a 1st or 2nd aspect which is phosphorus.

In a fourth aspect of the present invention,

The said shape processing is the photomask substrate in any one of the 1st-3rd aspect which forms one or several recessed parts in the said main surface.

According to a fifth aspect of the present invention,

A photomask having a transfer pattern formed on a main surface thereof, which is mounted in a proximity exposure apparatus, forms a proximity gap between a transfer object placed on a stage of the proximity exposure apparatus, and exposes the transfer pattern. As a manufacturing method of a photomask substrate for forming into the photomask used for transferring,

The proximity gap at a plurality of positions on the main surface is measured,

Among the fluctuations caused by the position of the proximity gap, a variation inherent to the proximity exposure apparatus is extracted,

The correction shape of the main plane of the photomask substrate is determined based on the variation inherent in the extracted proximity exposure apparatus and a predetermined gap variation allowance value,

It is a manufacturing method of the photomask board | substrate which performs shape processing into the said corrected shape on the main plane of the said photomask board | substrate.

In a sixth aspect of the present invention,

A photomask having a transfer pattern formed on a main surface thereof, which is mounted in a proximity exposure apparatus, forms a proximity gap between a transfer object placed on a stage of the proximity exposure apparatus, and exposes the transfer pattern. As a manufacturing method of a photomask substrate for forming into the photomask used for transferring,

A sample mask substrate is mounted on the proximity exposure apparatus, a sample glass substrate is placed on a stage of the proximity exposure apparatus, and a plurality of positions of the main surface of the sample mask substrate are mounted. Measuring gap proximity to obtain gap data indicating variation in proximity gap by position;

Extracting variation components inherent to the proximity exposure apparatus from the gap data to obtain inherent gap data;

Obtaining shape processing data to be applied to the photomask substrate using the inherent gap data and a predetermined gap variation tolerance value;

Process of performing shape processing on the main surface of the photomask substrate using the shape processing data

It is a method of manufacturing a photomask substrate comprising a.

According to a seventh aspect of the present invention,

The method of manufacturing the photomask substrate according to the sixth aspect, wherein, in the step of obtaining the intrinsic gap data, the component of the proximity gap variation caused by the sample mask substrate is removed during the variation of the proximity gap in the plurality of positions. to be.

According to an eighth aspect of the present invention,

In the step of obtaining the intrinsic gap data, the photomask substrate according to the sixth or seventh aspect, wherein the component of the proximity gap variation caused by the sample glass substrate is removed during the variation of the proximity gap in the plurality of positions. It is a manufacturing method.

According to a ninth aspect of the present invention,

In the photomask substrate according to any one of the sixth to eighth aspects, wherein the warp suppression means included in the proximity exposure apparatus is used to suppress warpage caused by the weight of the sample mask substrate at the time of measuring the proximity gap. It is a manufacturing method.

According to a tenth aspect of the present invention,

The process of obtaining the said shape processing data WHEREIN: The part which exceeds the said gap variation tolerance value among the proximity gap changes by the position intrinsic to the said proximity exposure apparatus shown by the said unique gap data is specified, and the said specified It is the manufacturing method of the photomask board | substrate in any one of the 6th-9th aspect which performs shape processing with respect to the specific area | region containing a part.

According to an eleventh aspect of the present invention,

Among the inherent gap data, when the height of the main surface at the position where the proximity gap becomes the maximum value is Z1 and the gap variation allowable value is T, the height on the main surface is (Z1-T). It is a manufacturing method of the photomask board | substrate in any one of the 6th-10th aspect which specifies the part lower than), and performs shape processing with respect to the specific area | region containing the said specific part.

In a twelfth aspect of the present invention,

The said shape processing is a manufacturing method of the photomask board | substrate in any one of 5th-11th aspect which forms one or several recessed parts in the main surface of the said photomask board | substrate.

According to a thirteenth aspect of the present invention,

An optical thin film for forming the transfer pattern on the main surface of the photomask substrate according to any one of the first to fourth embodiments or the photomask substrate according to the manufacturing method according to any one of the fifth to twelfth aspects. This is a formed photomask blank.

In a fourteenth aspect of the present invention,

It is the photomask in which the said transfer pattern was formed by patterning the optical thin film formed in the main surface of the photomask blank of 13th aspect by the photolithographic method.

In a fifteenth aspect of the present invention,

It is a photomask as described in a 14th aspect used for manufacture of a liquid crystal display device.

According to a sixteenth aspect of the present invention,

It is a pattern transfer method which transfers the transfer pattern formed in the said photomask on a to-be-transferred body by attaching the photomask which concerns on 15th aspect to the said proximity exposure apparatus used for the measurement of the said proximity gap, and exposing.

According to a seventeenth aspect of the present invention,

It is a manufacturing method of the liquid crystal display device using the pattern transfer method of 16th aspect.

An eighteenth aspect of the present invention,

In the proximity gap evaluation method of a proximity exposure apparatus,

By mounting a sample mask substrate to the proximity exposure apparatus, placing the sample glass substrate on the stage of the proximity exposure apparatus, and measuring the proximity gap at a plurality of positions of the main surface of the sample mask substrate, Obtaining gap data indicative of fluctuations in proximity proximity;

Extracting variation components inherent to the proximity exposure apparatus from the gap data to obtain inherent gap data;

It is a proximity gap evaluation method which calculates | requires the position where the proximity gap exceeding a change tolerance value arises, and the excess amount using the said unique gap data and a predetermined gap change tolerance value.

According to the present invention, the transfer accuracy can be improved by controlling the proximity gap within a certain numerical range when transferring the transfer pattern of the photomask to the transfer object by using the proximity exposure. In particular, the fluctuation of the proximity gap according to the exposure apparatus to be used can be greatly reduced.

1 is a schematic view illustrating a warpage correction mechanism of an exposure apparatus described in Patent Document 1. FIG.
It is a schematic diagram explaining the curvature correction mechanism of the exposure apparatus of patent document 2. FIG.
3 is a schematic diagram showing a simulation of correction for warpage of a photomask substrate.
FIG. 4 is a schematic diagram showing one step of the manufacturing process of the photomask substrate according to the present embodiment, and showing a state in which gap variation inherent in the measurement and exposure apparatus of the proximity gap is grasped.
Fig. 5 is a schematic diagram showing one step of the manufacturing process of the photomask substrate according to the present embodiment, (a) shows the appearance of proximity gap, (b) shows gap data inherent to the exposure apparatus, and (c) Is a diagram illustrating the surface shape of a photomask substrate formed so as to cancel gap data, respectively.
6 is a schematic diagram showing a step of determining a correction shape of a photomask substrate by applying a variation allowance value to gap data inherent in the exposure apparatus.

(Importance of Proximity Gap Uniformity)

When manufacturing the said TFT board | substrate and CF, the pattern transfer method which employ | adopted proximity exposure is used advantageously. In proximity exposure, a transfer member (hereinafter also referred to as a glass substrate) on which a resist film is formed and the pattern surface of the photomask are opposed to each other and held, and the pattern surface faces downward, and the back surface of the photomask (pattern forming surface). The pattern is transferred to the resist film by irradiating light from the surface on the opposite side). At this time, a predetermined micro-gap (proxy gap) is formed between the photomask and the transfer member. The proximity gap can be, for example, about 30 to 300 μm, more preferably about 50 to 180 μm. Moreover, the photomask is provided with the transfer pattern by which predetermined | prescribed patterning is performed to the optical film (light shielding film or semi-transmissive film which partially transmits exposure light) formed in the main surface of a transparent substrate. The main surface which forms this transfer pattern is a pattern surface.

According to the proximity exposure method, if the proximity gap is kept uniform over the entire pattern surface, the transfer accuracy can be transferred with a high pattern accuracy, and if there is a guarantee that the proximity gap is kept uniform, the proxy By setting the meity gap small, the transfer pattern with higher resolution is obtained, and therefore the importance of controlling the in-plane variation of the proximity gap (that is, the proximity gap variation by position) is increasing. However, it is not easy to keep this proximity gap uniform in plane.

For example, the photomask substrate of the present invention can be advantageously applied to photomasks for manufacturing display devices such as liquid crystal displays, and the size of the main surface thereof is, for example, the long side L1 of 600 to 1400 mm, The short side L2 may be about 500 to 1300 mm, and the thickness T may be about 5 to 13 mm. In accordance with the trend of increasing the size of the photomask and increasing the weight, it has become a big problem to suppress fluctuations in the proximity gap during transfer.

(Holding method of exposure apparatus)

In the proximity exposure apparatus, there exist a plurality of methods of mounting (holding in the apparatus) a photomask.

Generally, when attaching a photomask to a proximity exposure apparatus, the outer side of the area | region (also called a pattern area) in which the pattern for transfer was formed of the pattern surface is hold | maintained by the holding member of an exposure apparatus. For example, in the apparatus described in patent document 1 shown in FIG. 1, when the area | region of each vicinity of two opposite sides of the rectangular main surface of the photomask 1 was set as the holding area (two side holding) In this holding area, the mask holder 2, which is a holding member of the exposure apparatus, abuts from below (lower holding), and can hold the photomask. The contact surface between the photomask and the holding member may be adsorbed under reduced pressure (see Japanese Patent Application Laid-Open No. 2010-2571), or as shown in FIG. 1B, may be contact by tangential contact. In the case of such lower surface holding, the photomask is held from below by the two holding members, so that the photomask is placed in the exposure apparatus in a substantially horizontal posture while maintaining a predetermined proximity gap with the glass substrate. Alternatively, the vicinity of the four sides of the main surface may be held from below (four sides held), respectively.

For example, in the apparatus described in patent document 2 shown in FIG. 2, the holding member is made into the holding area which is the outer side of the pattern area | region of the photomask M and the back surface (surface on the opposite side to a pattern surface), and a holding member here The photomask M can be supported from the upper surface side by bringing the phosphor mask holder 1 into contact (upper surface holding), and attracting and adsorbing these contact surfaces through the mask adsorption passage 1a.

(Bending suppression means of exposure apparatus and its effect)

When the photomask substrate is attached to a proximity exposure apparatus (hereinafter also referred to simply as an exposure apparatus), it is known from the documents 1 to 3 that the photomask substrate is bent by its own weight. Therefore, the exposure apparatus provided with the curvature suppression means which suppresses the curvature of the photomask board | substrate attached to the exposure apparatus is provided.

For example, in the apparatus of Patent Document 1 shown in FIG. 1, the photomask 1 is held when the photomask 1 is provided, and the mask holder 2 and the photomask 1 which hold two sides of the photomask are here. Bending correction is performed on the principle of lever by the two bending correction bars 3 which push the edges of both sides of the upper side from upper side.

In addition, in the apparatus of patent document 2 shown in FIG. 2, when holding and holding photomask M by upper surface holding (adsorption), the airtight chamber SA is formed above the photomask M, and the inside of the airtight chamber SA is an air suction path ( By exhausting through 1b), by using the negative pressure of the airtight chamber SA, the photomask M is floated in the direction opposite to the gravity direction, and a method of correcting the warpage of the photomask M is adopted.

Therefore, the inventors simulated the correlation between the warpage suppression means and the warpage of the photomask substrate. 3 shows a simulation in which the holding member for holding the two sides and the bending suppression means for performing the bending suppression based on the principle of the lever are applied. FIG. 3A illustrates a situation where the photomask substrate is attached to the proximity exposure apparatus. The photomask substrate is supported from below by a holding member supported from below in the vicinity of two opposite sides (two sides spaced 800 mm apart). And the bending behavior of the photomask board | substrate at the time of changing the force pushed from upper direction on the outer side of a holding member gradually was computed. The horizontal axis of FIG. 3B has shown the position (mm) on a photomask board | substrate, and the vertical axis | shaft has shown the amount of curvature (micrometer), respectively. In addition, each line segment in a figure has shown the curvature behavior at the time of changing pressure, and pressurization makes the reference | standard 1 the pressure at the time of curvature becoming zero.

As shown in Fig. 3B, when the pressure applied from the upper side is gradually increased, the amount of warpage of the central portion of the photomask substrate gradually decreases with this, and at some point, the warpage is substantially eliminated. Increasing the pressure further causes the photomask substrate to deflect upwards.

In this way, if the warpage suppressing means included in the exposure apparatus is appropriately used, it can be seen that in-plane nonuniformity of the proximity gap due to warpage of the photomask substrate is reduced. In other words, if the main cause of variation due to the position of the proximity gap is warping by its own weight of the photomask substrate, it is considered that the warpage suppression means of the exposure apparatus can suppress this variation to some extent.

The present inventors further developed this knowledge to examine photomask substrates that enable highly accurate pattern transfer, which manages variations due to proximity gap position more precisely and becomes more difficult. . In other words, in order to improve the transfer accuracy, it was found that it was not enough to find a means for suppressing warping due to the weight of the photomask substrate as described above, and earnestly examined.

(Reason considered to be insufficient only by bending restraint means)

Since there are a plurality of methods and shapes of the photomask holding method and the warpage suppressing means of such an exposure apparatus, the direction, magnitude, and pressure per area of the force accommodated by the photomask substrate are not the same depending on their differences. not. Thus, for example, even if the self-weight warping is completely eliminated by the warpage suppression means, the photomask substrate is not only in contact with the holding member of the exposure apparatus (or in contact with each other, but also in tangent lines) and in contact with the warp suppression means (or in contact with each other. It seems that I receive different kinds of power by). In addition, it is estimated that the direction, magnitude | size, and pressure per area of the force which a photomask board | substrate accommodates differ with the holding | maintenance system of the photomask which a exposure apparatus has, and the system of curvature suppression means. Moreover, even if the same holding method or the like is adopted, it is estimated that the size depends on the size of the photomask substrate, the repair method of each exposure apparatus, and the like. Moreover, since the stage of the exposure apparatus which mounts the glass substrate which comprises a to-be-transferred body is not a perfect flat surface, it has a factor which affects a proximity gap. These factors are considered to generate fluctuations due to the position of the proximity gap, thereby affecting the transfer accuracy. In particular, with the miniaturization of the transfer pattern, in the precise transfer of the pattern having a line width of 2 to 15 µm, or about 3 to 10 µm, the proximity gap variation caused by various factors of the exposure apparatus cannot be ignored. have.

In view of the above, only the warp suppression means described in Patent Document 1 or Patent Document 2 is insufficient as a control of the proximity gap. Moreover, even the board | substrate of the "circular arc shape in which the surface opposite to mother glass was concave" described in patent document 3 can reliably suppress fluctuation of the proximity gap by factors other than its own weight bending. It is not possible.

Therefore, this inventor earnestly examined and obtained the following solution means in order to suppress in-plane fluctuations of a proximity gap. Hereinafter, an embodiment of the present invention will be described.

(Process for Obtaining the Photomask Substrate According to the Present Embodiment)

A glass material can be used as a material of the photomask board | substrate applied to this embodiment. For example, quartz glass, alkali-free glass, borosilicate glass, aluminosilicate glass, soda-lime glass can be used. Can be.

In addition, in this application, a "photomask substrate" is used as a material of a photomask blank, and means the state of the transparent substrate which processed the front and back of flat plates, such as glass, to predetermined shape and flatness. However, since the thin film is formed on the photomask substrate in this state, or the state in which the resist is further applied (photomask blank) and the thin film is patterned (photomask), the photomask substrate portion is substantially the same. In some cases, a photomask substrate may be appropriately used.

The photomask substrate of this embodiment can be obtained by the following processes.

1. Acquisition process of gap data and unique gap data

First, the fluctuation amount by the position of the proximity gap which a predetermined exposure apparatus has is grasped | ascertained. The proximity gap can be measured by attaching the sample mask substrate to the photomask holding portion of the exposure apparatus, placing the sample glass substrate on the stage where the transfer object of the exposure apparatus is placed, and measuring the distance therebetween. . That is, at a plurality of positions on the main surface of the sample mask substrate, the proximity gap, which is the distance between the sample mask substrate and the sample glass substrate, is grasped. Specifically, the proximity gaps at the plurality of measurement points on the main surface of the sample mask substrate are respectively measured. For example, in a region corresponding to the pattern region in the main surface of the sample mask substrate, lattice points of predetermined predetermined intervals (for example, predetermined values within a range of 10 mm to 300 mm) are set, and each lattice point is set. It can be a measuring point. As for the distance of a grid point, it is more preferable to select within the range of 50 mm-250 mm, for example.

A pattern region can be made into the area | region except the area | region within 50 mm from four sides which form an outer edge among the main surfaces of a sample mask substrate, for example.

The proximity gap can be measured by, for example, irradiating light from an oblique upper side (or lower side) of the sample mask substrate, detecting the reflected light from the mask pattern surface (main surface) of the sample mask substrate, and the reflected light from the glass substrate. Can be. Alternatively, as described in Patent No. 3953841, a method of measuring using the reflection of the glass plate constituting the hermetic chamber may be applied.

Here, the case where the apparatus provided with the bending suppression means which presses the outer side of a holding member from the upper side as an exposure apparatus of two sides holding and lower surface holding is demonstrated as an example.

At the time of measuring the proximity gap, it is preferable to perform using the warpage suppression means which an exposure apparatus has. For example, it is preferable to measure the proximity gap while applying the optimum conditions (conditions that warpage becomes almost zero) obtained in the simulation shown in FIG. 3 described above.

Since the proximity gap in each measurement point obtained in this way differs (changes) with a position, it shows the fluctuation by the position of a proximity gap. In this way, the data of the proximity gap with the variation is referred to as the gap data A.

In addition, the gap data A obtained above is actually the flatness of the sample mask substrate (pattern surface, the pattern surface and the back surface in the case of upper surface holding), the flatness (transfer surface and the back surface) of the sample glass substrate, and the like. It means the proximity gap affected by. However, for the purpose of this embodiment, it is preferable to obtain gap data which does not include fluctuations other than the proximity gap fluctuations inherent in the exposure apparatus.

The variation inherent in the exposure apparatus among the variations due to the position of the proximity gap is a variation with reproducibility in the predetermined exposure apparatus, and includes the following (1) to (3).

(1) Gap fluctuation due to photomask self weight warping when a photomask substrate is attached to the exposure apparatus

(2) Gap fluctuations due to the mechanism (shape holding part, contact area, etc.) of the exposure apparatus holding the photomask, or the method (pressing position, pressure) of the warp suppression means.

(3) Gap fluctuation by unevenness of the stage of mounting the to-be-transferred body (glass substrate) of the exposure apparatus

On the other hand, fluctuations other than fluctuations inherent to the exposure apparatus include the following (4) and (5).

(4) Gap fluctuation due to unevenness of the pattern surface of the photomask substrate (in case of top holding, gap fluctuation due to unevenness of the back surface is also included)

(5) Gap fluctuation due to nonuniformity of the transfer surface of the transfer target body (glass substrate) and its back surface mounted on the stage of the exposure apparatus

In this embodiment, as long as a predetermined exposure apparatus is used, it is an object to obtain a means for taking effective countermeasures against gap fluctuations that are reproducible and can calculate a quantitative correction amount. Therefore, the measurement of the proximity gap on which the correction amount is based should be performed using an ideal sample mask substrate having no unevenness in flatness and an ideal sample glass substrate configured similarly. Therefore, the sample mask substrate and the sample glass substrate of the state near the above should be prepared and analyzed.

In addition, when it is difficult to carry out such an ideal board | substrate manually, what is necessary is just as follows. That is, it is preferable to obtain the data which extracted the fluctuation inherent in the exposure apparatus based on the gap data A. That is, it is preferable to remove the component by the fluctuations other than the inherent fluctuations in the exposure apparatus. Therefore, below, the gap variation component by the flatness of the used sample glass substrate can be removed from gap data A first.

Specifically, a plurality of sample glass substrates are prepared, the proximity gaps are sequentially measured, and the individual differences of the sample glass substrates are eliminated by averaging the values for each measurement point of the gap data A obtained using each. Thereby, the proximity gap fluctuation (said (5)) resulting from a sample glass substrate can be eliminated. This is gap data shown in Fig. 4A (this is called gap data B).

Next, the gap variation component attributable to the pattern plane flatness of the sample mask substrate is removed. Here, another flatness measurement is performed on the pattern surface of the sample mask substrate, and the obtained flatness data (shown in FIG. 4B) is shown in FIG. 4A for each corresponding measurement point. It can be subtracted from the gap data B.

As a measuring apparatus used for flatness measurement, the planar measuring device by Seiko Kuroda, and the thing of Unexamined-Japanese-Patent No. 2007-46946 are applicable, for example. Specifically, on the pattern surface of the sample mask, a plurality of lattice points are formed at predetermined intervals in the same manner as the above-described proximity gap measurement, and the lattice points are measured as flatness measurement points. And when the reference plane which is substantially parallel to the main plane of the sample mask substrate is determined, the height information of each measuring point with respect to this reference plane is obtained, and this can be used as flatness data. In the measurement of flatness, it is preferable to hold | maintain and measure the board | substrate which is a test object perpendicularly | vertically so that the influence of gravity may not be strong enough.

Therefore, the gap data C shown in FIG. 4C obtained by subtracting the flatness data shown in FIG. 4B from the gap data B shown in FIG. 4A is a proxy unique to the exposure apparatus. The data indicating the measurable gap variation is referred to as unique gap data.

In addition, you may use another method about removal of the fluctuation component of said (4), (5). For example, in (4), a plurality of sample mask substrates are prepared, and the above (4) to the used sample mask can be removed by averaging the values for each measurement point of the gap data A obtained using each.

For (5), the flatness measurement is performed in advance on two main surfaces of the sample glass substrate, and the flatness data for each measurement point (actually, the difference in the flatness data for each measurement point to which both main surfaces correspond). , That is, the degree of parallelism data), may be subtracted from the numerical value for each measurement point to which the gap data B as a basis corresponds.

As mentioned above, since the obtained intrinsic gap data shows the gap variation by the position intrinsic to the exposure apparatus to be used, the shape determination of the photomask substrate of this embodiment is performed based on this.

2. Process of Acquiring Shape Machining Data

The intrinsic gap data obtained above represents a gap variation caused by the exposure apparatus when the exposure apparatus is set with an ideally flat photomask substrate and an ideally flat glass substrate. Therefore, in order to prevent this gap variation from occurring, the gap variation can be substantially zero by processing the pattern surface of the photomask substrate in which the variation is inverted in advance. This state is shown in FIG.4 (d). In FIG.4 (d), shape processing data for forming the pattern surface of the shape to invert is shown based on the gap variation shown to FIG.4 (c). In addition, in FIG.4 (d), the state of the surface shape of the photomask board | substrate corrected in order to cancel the gap fluctuation shown in FIG.4 (c) is shown from the pattern surface side overturning the photomask board | substrate. Therefore, the corresponding position is moved to the symmetrical position.

In FIG.4 (d), shape processing data for forming the pattern surface of the shape to invert is shown based on the gap variation shown to FIG.4 (c). That is, if a photomask substrate having a pattern surface shape shown in Fig. 4D is prepared and a photomask is produced on the basis of this, in the actual exposure apparatus, the residual of gap variation is substantially eliminated. This is shown in Fig. 4E.

The above is explained in a side view using FIG.

In FIG. 5A, even if a photomask substrate having an ideal flatness and a panel substrate having an ideal flatness are set in an actual exposure apparatus, a state in which the proximity gap is caused depending on the in-plane position is shown. Indicates. That is, the gap value becomes the largest in the portion where the distance between the photomask substrate and the panel substrate is maximum (FIG. 5B). This corresponds to the inherent gap data (gap data C) described above.

Although the gap fluctuation range (difference between the maximum and minimum of a gap) differs by an actual exposure apparatus, it is common that it is a numerical value within the range of 20-70 micrometers. For example, in order to make it zero for the exposure apparatus whose gap variation width is 50 micrometers, this 50 micrometers can be canceled by the shape processing of the pattern surface of a photomask substrate. The surface shape of the photomask substrate at this time is shown in Fig. 5C. In FIG. 5C, when the curve is a pattern surface, the upper side is the space side and the lower side is the photomask substrate side.

In terms of transfer accuracy, the gap variation is preferably smaller. However, in proximity exposure, the extent to which the gap variation due to the in-plane position is allowed depends on the use and specification of the product to be obtained. Therefore, it is more preferable to set the variation tolerance value according to the target accuracy. desirable. As a reason for this, the shape processing of the photomask substrate for making the gap variation zero can be achieved in terms of actual production efficiency and yield, such as a large amount of removal of removal processing (polishing, etc.), or a shape difficult to be processed. The thing which is not necessarily advantageous is mentioned.

Therefore, the case where the gap variation allowable value according to an applied product or a specification is taken into consideration when planning in-plane uniformity of proximity gap is demonstrated below. For example, in the product to be obtained, the maximum allowable gap variation value (hereinafter referred to as variation allowance value T (µm)) can be a predetermined value between 40 and 10 µm. That is, according to the required precision of the liquid crystal display to be obtained, it is possible to set it to 10 m for a very high definition, 40 m for a slightly loose specification, to 20 m or 30 m for an intermediate one.

In FIG. 6, the process of determining the correction shape of a photomask board | substrate is applied by applying the value of the change tolerance value T to gap data C. As shown in FIG.

In FIG. 6A, the correction shape is determined with respect to the gap data C based on the maximum value (a portion where the gap is maximized). That is, when the position P used as the maximum gap is matched with the upper limit of the variation allowable value T on the pattern surface after the shape machining, the portion where the variation allowable value T cannot be satisfied (the portion where the gap becomes smaller than the allowable range) The diagonal line part of Fig.6 (a) is correct | amended by shape processing. In other words, when the height of the position P serving as the maximum gap is set to Z1, a portion lower than (Z1-T) is specified, and at least the shape processing for removing this portion is performed. This method is referred to as the maximum reference method.

In addition, the height here is the distance in the vertical direction with respect to the photomask main plane (assuming an ideal main plane), and can be considered as the height with respect to the ideal main plane.

For example, when the maximum reference method is adopted, the concave shape shown by the dotted line in Fig. 6B may be formed on the pattern surface of the photomask substrate. In addition, since this recessed part is correction | amendment of the part from which a gap becomes small too much, although removal process is needed even to the shape of a dotted line, removal process may be continued beyond this and the removal process to a solid line is accepted. . That is, it can be said that between the dotted line and the solid line is the margin of removal processing. And the area | region used as the object of processing between both becomes the specific area | region mentioned in this invention. Moreover, according to the maximum value reference system, shape processing with respect to a photomask substrate material forms a concave shape.

In FIG. 6B, the correction shape is determined for the gap data C based on the center value of the maximum value and the minimum value. That is, with respect to the gap center value, the portion where the gap becomes larger than 2 / T and the portion where the gap becomes smaller than 2 / T is corrected by the shape processing. In other words, when the height of the position where the proximity gap indicates the intermediate value is Z2, the portion on the main surface becomes higher than (Z2 + T / 2) and (Z2-T / 2). Each part to be lowered is specified, and this part is specified and shape processing is performed. This method is referred to as the central reference method.

When the center reference method is adopted, as shown in Fig. 6D, the removing process may be performed like a dotted line, and between the dotted line and the solid line is allowed as a margin of the removing process.

In addition, in FIG.6 (c), with respect to gap data C, the correction shape is determined based on the minimum value (part in which a gap becomes minimum). That is, when the position B which becomes a minimum gap is matched with the lower limit of the variation tolerance value T in the pattern surface after shape processing, the part which cannot satisfy | generate the variation tolerance value T (the part in which a gap exceeds the permissible range, FIG. The diagonal line part of (e) of 6) is correct | amended by shape processing. That is, when setting the height of the position B which becomes a minimum gap as Z3, the part which becomes higher than (Z3 + T) is specified, and the shape process which removes another thing leaving this part at least is performed. This method is referred to as the minimum value method.

What is necessary is just to employ | adopt the correction shape shown in FIG.6 (c) if a minimum value reference system is employ | adopted. Specifically, a convex shape indicated by a dotted line may be formed on the pattern surface, and as a margin, an area between the dotted line and the solid line is allowed.

Also in the center value reference method or the minimum value reference method, the area | region between the dotted line and solid line of FIG.6 (d), (f) becomes a specific area | region.

The correction shape differs depending on which of the three methods is employed. Therefore, the most suitable system can be selected according to the apparatus and process used for a process.

For example, according to the maximum value reference method, since the removal amount (work quantity) from the substantially flat photomask substrate material can be made small, it is preferable. In addition, when making a removal process a grinding | polishing process and forming a concave shape in the surface, the removal amount is locally made large by increasing the polishing load of the part. In the case of using such a method, it is more efficient to form the concave portion locally than to form the convex portion locally (removing the periphery of the position of the convex portion), so the maximum reference method is advantageous.

The above consideration is made and the correction shape when the variation allowable value T is applied is determined. 4 (f) to (n) show this in plan view.

(C) to (e) in Fig. 4 (f), in which the variation allowance T is set to zero and the determination of the correction shape to eliminate the gap variation when using the photomask substrate processed is performed. ) To (h) show the case where the correction shape is determined in the maximum value reference method. In this case, a photomask substrate having a surface shape in which the gap data shown in FIG. 4C is used as it is is not reversed, but is formed, based on the maximum position in FIG. 4C. In addition, only the part which cannot satisfy | perform a variation tolerance value (it was set to 35 micrometers here) was made into the object of shape processing. As apparent from Fig. 4G, it can be seen that the shape processing is good only by forming the recesses. In addition, according to FIG.4 (h), although the gap variation remains after shape processing, it turns out that the variation width is 35 micrometers or less of the variation tolerance value T.

Similarly, in Fig. 4 (i) to (k), the shape variation data and the gap variation remaining after the shape processing when the central reference method is adopted are shown. 4 (l) to (n) show the same data when the minimum value reference system is adopted.

3. Process of performing shape processing on photomask substrate

Generally, a photomask substrate can be obtained by preparing the glass substrate material for photomasks, and flattening two main planes by grinding | polishing. For example, in each of the back surface of a pattern surface and a pattern surface, the glass substrate material which made flatness 5-30 micrometers can be used. The glass substrate material obtained in this way is used as a photomask substrate material, and can also be shape-processed and the photomask substrate of this embodiment can be obtained.

The shape to be processed is determined by the method mentioned above. For example, shape processing can be performed by a well-known processing apparatus using the shape processing data shown to Fig.4 (g).

For example, shape processing can be performed using the grinding | polishing apparatus provided with a rotatable polishing surface plate, the polishing pad provided on the polishing plate, and the abrasive supply means which supplies an abrasive to the surface of a polishing pad. When holding the glass substrate material on the polishing pad and forming a recess by shape correction, the glass substrate material can be polished on one surface by pressing so that the pressure of the polishing pad against the substrate becomes larger than other regions. . When pressurizing, the apparatus provided with the some pressurized body and having control means which can perform pressure pressurization control independently of each pressurized body is preferable. When forming a convex part, pressurization control can be performed with respect to the peripheral area | region of a convex part so that a larger removal amount may be carried out.

Or you may perform shape processing using a vertical price milling machine. A polishing cup head having a polishing cloth adhered to the processing portion of the apparatus can be provided, the polishing liquid can be supplied, and processing can be performed while controlling the height direction.

In the polishing step, the above-described shape processing may be performed on the glass substrate material subjected to rough polishing and precision polishing, or after rough processing, precision processing is performed, and shape processing reflecting the above shape processing data is performed. You may also

The kind and particle diameter of the abrasive | polishing agent to be used can be suitably selected according to a board | substrate material and desired flatness. Examples of the abrasive include cerium oxide, zirconium oxide, colloidal silica, and the like. The particle diameter of the abrasive can be several tens of nm to several micrometers.

4. Composition of Photomask Substrate

The photomask substrate which concerns on this embodiment is comprised as follows.

That is, a transfer pattern is formed on the main surface, mounted on a proximity exposure apparatus, a proximity gap is formed between the transfer member placed on a stage of the proximity exposure apparatus, and the exposure pattern is exposed. As a photomask substrate for forming a photomask used for transferring,

In one or a plurality of specific regions on the main surface, the shape processing of the removal amount different from the peripheral region other than the specific region is performed to form a concave shape, a convex shape, or an uneven shape, thereby forming the photomask substrate in the proximity exposure apparatus. Fluctuation due to the position of the proximity gap, which occurs when

The said shape processing is comprised as a photomask board | substrate which reduces the variation inherent to the said exposure apparatus extracted from the fluctuation by the position of the said proximity gap.

The above-mentioned concave shape, convex shape, or uneven shape means the shape when the influence of gravity is excluded from the said photomask substrate. In addition, a peripheral area is the outer side of the said specific area | region, and means a peripheral area adjacent to the said specific area | region. This specific area | region is arbitrary area | region on the main plane of a photomask board | substrate, and is an area | region used for shape processing. It can be set as the shape processing area | region shown by the dotted line and solid line in FIG.6 (b), (d), (f). One or more of these specific areas are set on the main surface. In the case of plural setting, there are no restrictions on the types of convex shape, concave shape and concave-convex shape, and combinations thereof.

As a processing method, the removal process which removes a surface part by grinding | polishing etc., for example is applicable. In addition to polishing, it is also possible to apply a method such as sandblasting. The amount of removal different from the peripheral area means processing of the shape as removal deeper or shallow removal than the peripheral area. By increasing or decreasing the removal amount (for example, the polishing amount), a portion having a height higher or lower than other regions can be formed. Alternatively, by removing only a specific region, the height may be lower than that of other regions.

The shape processing may be offset so that the gap variation inherent in the exposure apparatus is within an allowable range (less than the allowable variation T) in the product. This variation allowable value T is determined based on the use and specification of the device to manufacture using the photomask of this embodiment. Therefore, in the photomask substrate of the present embodiment, the proximity gap variation formed when the photomask substrate is attached to the exposure apparatus is equal to or less than the gap variation tolerance value T with respect to the ideal glass substrate.

In addition, in this invention, when the area | region except the area | region except 50 mm from four sides which form the outer edge of the main surface of a photomask substrate is set as a pattern area, it is the thing which said shape processing was performed in the pattern area. desirable. On the other hand, in the area | region (outside the pattern area) within 50 mm from 4 sides, it can be said that the said shape processing is not performed, and in that case, it is advantageous at the following points.

Considering that the photomask substrate is mounted and used in the above-described two-side holding and the lower surface holding exposure apparatus, the photomask substrate has two opposite sides of the pattern surface (the pattern surface of the photomask substrate is rectangular). Is preferably a holding area in which the holding member of the exposure apparatus is in contact with the area within 50 mm from the opposing long side). Therefore, the surface of the photomask substrate is preferably high in flatness.

For example, it is preferable that Z / P is 0.08 or less when the height difference of arbitrary two points spaced by Pmm (5 <= P <= 15) in this area | region is Zmicrometer.

In addition, considering that the photomask substrate of the present invention is attached to and used on an exposure apparatus with four sides holding and a bottom holding, the exposure apparatus is held in an area within 50 mm from four sides of the pattern surface. Since the holding member is in contact with the holding region, the surface of the photomask substrate is preferably high in flatness, and it is preferable that the same Z / P is 0.08 or less.

In addition, when the photomask substrate of this invention is attached and used for the exposure apparatus of four sides holding | maintenance and the upper surface holding | maintenance, when using, it is exposure apparatus about the area within 50 mm from four sides of the back surface of a pattern surface. Since the holding member in contact with each other becomes a holding area, the surface of the photomask substrate is preferably high in flatness, and it is preferable that the same Z / P is 0.08 or less in this area.

In the flatness measuring method, the flatness measurement of the sample mask substrate can be performed in the same manner as described above.

5. Process of manufacturing photomask

There is no restriction | limiting in particular in the use of the photomask board | substrate of this embodiment. For example, it can apply to the photomask of the kind illustrated below. In particular, when used as a photomask for liquid crystal display device manufacture, the photomask used for manufacture of a CF (color filter) or a TFT (thin film transistor) board | substrate, the effect of this invention is acquired remarkably.

For example, by forming a light shielding film as an optical thin film on the main surface of the photomask substrate obtained by the above process, a binary mask blank for photomask manufacturing can be obtained. As the light shielding film, a film containing chromium or a chromium compound containing at least one selected from oxygen, nitrogen and carbon in chromium, silicon, tantalum, molybdenum and tungsten A film containing a metal, a metal oxide, a metal nitride, a metal oxynitride, a metal oxycarbide, a metal nitride carbide, a metal oxynitride carbide, or the like having a metal element selected from tungsten or the like as a main component can be used.

Or as an optical thin film, the semi-transmissive film which partially transmits exposure light at the time of exposure can also be used. You may laminate | stack a some thin film. The material of the translucent film can also be selected from the same materials as the light shielding film, and the exposure light transmittance can be adjusted to 5 to 80% by the composition and the film thickness.

Furthermore, by patterning using the said light shielding film or semi-transmissive film suitably, a multi-tone (multi-tone) mask can be obtained. That is, a multi-gradation photomask having a transfer pattern, which includes a light shielding portion that shields exposure light, a semi-transmissive portion that partially transmits the exposure light, and a light transmitting portion that substantially transmits the exposure light by exposing the transparent substrate, can be obtained. have. This is a mask which processes the resist pattern formed on the to-be-transferred body into the three-dimensional shape from which the residual film amount (height) differs with a position, and the effect which can pattern two or more times on the to-be-transferred body using one photomask. Is a mask obtained. For example, it can be used advantageously for manufacture of a color filter provided with the some photo spacer with a different height.

As a film formation method of the said optical thin film, well-known things, such as a sputtering method and a vacuum vapor deposition method, are applicable.

In the manufacturing process of a photomask, a well-known photography method can be applied. The optical thin film is formed on the principal plane (pattern surface) of the photomask substrate obtained by the above steps as many times as necessary, and a photoresist is applied to produce a photomask blank. Then, a pattern is drawn on the resist film by using a laser or an electron beam drawing device. Then, the drawn resist film is developed, and the thin film pattern is formed by wet etching or dry etching the optical thin film using the formed resist pattern as a mask. By repeating the above-mentioned photography process as many times as necessary, a photomask having a desired transfer pattern can be manufactured.

6. Process of performing pattern transfer

The exposure apparatus can use a well-known thing for proximity exposure. As an exposure light source, the light source of the wavelength range containing i line | wire, h line | wire, and g line | wire can be used.

The photomask obtained by the photomask substrate of this embodiment is a photomask for attaching and using to the exposure apparatus used for the measurement of said proximity gap. There is no restriction | limiting in particular in the board | substrate holding mechanism of the exposure apparatus for holding a photomask substrate, as long as it is the same as the exposure apparatus used for the measurement of a proximity gap. The above can be applied to any of the two-sided holding, the four-sided holding, the bottom holding, and the top holding. In the case where the bending suppression means or the like is applied at the time of the measurement of the proximity gap, the exposure is performed in the same manner at the time of pattern transfer.

When attaching the photomask substrate of this embodiment to the said exposure apparatus, it attaches with reference to the direction of the photomask substrate determined at the time of shape processing. That is, it mounts so that the direction of a photomask board | substrate may match at the time of a measurement of a proximity gap and a pattern transfer.

In addition, it is as mentioned above that the correction shape of a photomask board | substrate differs by the method of application of a gap variation tolerance range (variation tolerance value T). That is, the setting value of the proximity gap set to the exposure apparatus at the time of pattern transfer differs depending on whether the photomask substrate is concave or convex.

According to the present embodiment, since the variation of the proximity gap can be controlled within a predetermined range, the set value of the proximity gap itself can be made smaller than in the prior art. That is, the distance between the pattern surface of the photomask and the resist film surface of the transfer target can be set small, and the resolution can be raised. For example, the set value of the proximity gap set to the exposure apparatus at the time of pattern transfer can be 30-180 micrometers.

As mentioned above, according to this embodiment, the variation factor of the proximity gap resulting from the exposure machine to be used can be largely eliminated. In addition, the warpage caused by the weight of the photomask itself is also one of the fluctuation factors of the proximity gap caused by the structure of the exposure machine to be used, but according to the inventors' review, the fluctuation factors caused by the exposure apparatus cannot be ignored. When present to such an extent, according to the present embodiment, it becomes possible to effectively suppress such fluctuation in proximity.

There is no restriction | limiting in particular in the application use of the photomask which concerns on this embodiment. Moreover, as mentioned above, when used as a photomask for liquid crystal display device manufacture, a remarkable effect is acquired. For example, when the photomask according to the present embodiment is used as a photomask for manufacturing a TFT substrate, since the proximity gap can be controlled within a predetermined allowable range, the accuracy of the pattern line width and coordinates can be greatly improved. Moreover, when used as a photomask for CF manufacture, when manufacturing a black matrix and a color plate, line width precision and coordinate precision can be improved significantly, for example. Furthermore, when manufacturing a photo spacer which is responsible for the gap accuracy between TFT-CF, the accuracy of the shape of the spacer (shape in the X direction, Y direction, height in the Z direction and slope shape in plan view) is improved. The effect mentioned specifically is obtained.

7. How to evaluate proximity gap

As described above, according to the present embodiment, it is possible to accurately and efficiently evaluate the proximity gap when the photomask is set in the exposure apparatus.

Specifically, a sample mask substrate is mounted on the proximity exposure apparatus, the sample glass substrate is placed on a stage of the proximity exposure apparatus, and the proximity gaps at multiple positions of the main surface of the sample mask substrate are measured. Thereby obtaining gap data indicating variation in proximity gap due to position;

Extracting variation components inherent to the proximity exposure apparatus from the gap data to obtain inherent gap data;

By using the inherent gap data and a predetermined gap variation allowance value, the position where the proximity gap exceeding the variation allowance value is generated and the excess amount thereof are obtained to determine the proximity gap when the photomask is set in the exposure apparatus. Can be evaluated accurately and efficiently.

<Other embodiments of the present invention>

As mentioned above, although embodiment of this invention was described concretely, this invention is not limited to embodiment mentioned above, It can variously change in the range which does not deviate from the summary.

Claims (18)

A transfer pattern is formed on a main surface, mounted on a proximity exposure apparatus, a proximity gap is formed between the transfer target body placed on a stage of the proximity exposure apparatus, and exposed, thereby transferring the transfer pattern. As a photomask substrate for forming a photomask to be used,
In one or a plurality of specific regions on the main surface, the shape processing of the removal amount different from the peripheral region other than the specific region is performed to form a concave shape, a convex shape, or an uneven shape, thereby forming the photomask substrate in the proximity exposure apparatus. Fluctuation due to the position of the proximity gap, which occurs when
The shape processing reduces a variation inherent in the proximity exposure apparatus extracted from the variation due to the position of the proximity gap. The method of claim 1,
The main surface on which the shape processing is performed has a correction shape determined on the basis of the variation inherent in the extracted proximity exposure apparatus. The method of claim 1,
The shape processing is performed only on a specific area on the main surface, in which the variation inherent in the extracted proximity exposure apparatus includes an area exceeding a predetermined gap variation allowable value. Photomask substrate. The method of claim 1,
The said shape process forms one or several recessed parts in the said main surface, The photomask board | substrate characterized by the above-mentioned. A photomask having a transfer pattern formed on a main surface thereof, which is mounted in a proximity exposure apparatus, forms a proximity gap between a transfer object placed on a stage of the proximity exposure apparatus, and exposes the transfer pattern. As a manufacturing method of a photomask substrate for forming into the photomask used for transferring,
The proximity gap at a plurality of positions on the main surface is measured,
The variation inherent to the proximity exposure apparatus is extracted from the variation by the position of the proximity gap,
The correction shape of the main plane of the photomask substrate is determined based on the variation inherent to the extracted proximity exposure apparatus and a predetermined gap variation allowable value,
The manufacturing method of the photomask board | substrate characterized by performing the shape process made into the said corrected correction shape to the main plane of the said photomask board | substrate. A photomask having a transfer pattern formed on a main surface thereof, which is mounted in a proximity exposure apparatus, forms a proximity gap between a transfer object placed on a stage of the proximity exposure apparatus, and exposes the transfer pattern. As a manufacturing method of a photomask substrate for forming into the photomask used for transferring,
By mounting a sample mask substrate to the proximity exposure apparatus, placing the sample glass substrate on the stage of the proximity exposure apparatus, and measuring the proximity gap at a plurality of positions of the main surface of the sample mask substrate, Obtaining gap data indicative of fluctuations in proximity proximity;
Extracting variation components inherent to the proximity exposure apparatus from the gap data to obtain inherent gap data;
Obtaining shape processing data to be applied to the photomask substrate using the inherent gap data and a predetermined gap variation tolerance value;
And a step of performing shape processing on the main surface of the photomask substrate by using the shape processing data. The method according to claim 6,
The process for obtaining the intrinsic gap data, wherein the component of the proximity gap variation caused by the sample mask substrate is removed from the variation of the proximity gap in the plurality of positions. The method according to claim 6,
In the step of obtaining the intrinsic gap data, a component of the proximity gap variation caused by the sample glass substrate is removed from the variation of the proximity gap in the plurality of positions. The method according to claim 6,
A method for manufacturing a photomask substrate, wherein the warp suppression means included in the proximity exposure apparatus is used in order to suppress warpage caused by the weight of the sample mask substrate at the time of measuring the proximity gap. The method according to claim 6,
The process of obtaining the said shape processing data WHEREIN: The part exceeding the said gap variation tolerance value is specified among the proximity gap changes by the position unique to the said proximity exposure apparatus shown in the said unique gap data, The said specific gap is specified, The shape processing is performed with respect to the specific area | region containing a part, The manufacturing method of the photomask substrate characterized by the above-mentioned. The method according to claim 6,
Among the inherent gap data, when the height of the main surface at the position where the proximity gap becomes the maximum value is Z1 and the gap variation allowable value is T, the height on the main surface is (Z1-T). A portion lower than) is specified, and a shape processing is performed on the specific region including the specific portion. 12. The method according to any one of claims 5 to 11,
The said shape processing forms one or several recessed parts in the main surface of the said photomask substrate, The manufacturing method of the photomask substrate characterized by the above-mentioned. The optical mask for forming the said transfer pattern was formed in the main surface of the photomask board | substrate in any one of Claims 1-4, The photomask blank characterized by the above-mentioned. The transfer mask is formed by patterning an optical thin film formed on the main surface of the photomask blank according to claim 13 by a photolithography method. 15. The method of claim 14,
It is used for manufacture of a liquid crystal display device, The photomask characterized by the above-mentioned. The transfer mask formed on the photomask is transferred onto a transfer object by attaching the photomask according to claim 15 to the proximity exposure apparatus used for the measurement of the proximity gap and exposing the pattern. Way. The pattern transfer method of Claim 16 is used, The manufacturing method of the liquid crystal display device characterized by the above-mentioned. In the proximity gap evaluation method of a proximity exposure apparatus,
By mounting a sample mask substrate to the proximity exposure apparatus, placing the sample glass substrate on the stage of the proximity exposure apparatus, and measuring the proximity gap at a plurality of positions of the main surface of the sample mask substrate, Obtaining gap data indicative of fluctuations in proximity proximity;
Extracting variation components inherent to the proximity exposure apparatus from the gap data to obtain inherent gap data;
A proximity gap evaluation method, wherein the position where the proximity gap exceeding the variation tolerance value occurs and the excess amount are calculated using the inherent gap data and a predetermined gap variation tolerance value.

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