KR20120116877A - Substrate for photomask, photomask, method for manufacturing photomask and method for transfering pattern - Google Patents

Abstract

PURPOSE: A substrate for a photo-mask, the photo-mask, a manufacturing method of the photo-mask, and a pattern transferring method are provided to increase the coordinate precision over the entire surfaces of transferring patterns. CONSTITUTION: A substrate for a photo-mask forms transferring patterns on a first main surface. The thickness of the substrate is T mm. A second main surface is the rear side of the first main surface. When the height difference of two points with the distance of 10 mm is ΔZb um on the second main surface, the ΔZb in the region of the second main surface corresponding to the pattern region of the first main surface is less than or equal to (1/T)x3.0. The photo-mask is used for a proximity exposure process or a color filter manufacturing process. [Reference numerals] (AA) Manufacturing a mask(drawing); (BB) Using the mask(exposure); (CC) Flat-aligned state of the mask on a stage; (DD) Separated state of the mask

Description

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

The present invention relates to a photomask substrate, a photomask, a manufacturing method of a photomask, and a pattern transfer method.

The liquid crystal display device which a computer, a portable terminal, etc. comprise is a TFT board | substrate (henceforth TFT) which formed the TFT (thin-film transistor) array on the transparent base material, and the color which formed the RGB pattern on the transparent base material. The filter is bonded together and the structure which enclosed the liquid crystal was provided in between. The color filter (hereinafter also referred to as CF) is a process of forming a black matrix layer constituting a boundary of color on one main surface of the light transmissive substrate, and one week of the light transmissive substrate partitioned by the black matrix layer. It is manufactured by sequentially performing the process of forming color filter layers (henceforth a color layer), such as a red filter layer, a green filter layer, and a blue filter layer on the surface. The TFT and the color filter can also be manufactured by applying photolithography using a photomask.

On the other hand, since the photomask is slightly bent by its own weight when the photomask is set to the exposure machine and the pattern is transferred, Patent Document 1 discloses a support mechanism of the exposure machine for reducing this warpage.

Japanese Patent Application Laid-open No. Hei 9-306832

The expectation of the performance improvement required for a liquid crystal display device is increasing. In particular, a display device having a small size such as a portable terminal and requiring a high-definition image is required to have a performance exceeding a conventional product in several respects. Sharpness of color (no color blur), reaction speed, resolution. Due to such a request, the precision of pattern formation is demanded more in the photomask which manufactures TFT and CF than before.

For example, in a photomask for forming a TFT, in order to improve the reaction speed of the liquid crystal display device, the TFT pattern itself becomes fine or a photomask is used in combination with a finer TFT together with the main TFT. In forming the pattern, the line width of the fine dimension must be formed precisely and precisely. In addition, since the TFT and CF are used to overlap each other, if the positioning at the time of transfer is not controlled very precisely and precisely together with the coordinate accuracy of each pattern on the photomask, a position shift occurs between the two, resulting in the operation of the liquid crystal. There is a risk of failure.

On the other hand, the photomask of CF formation also has a difficulty in the following points. As described above, since the black matrix layer and the color layer are used to overlap each other, the pattern formation on the mask is precisely and precisely performed, and when the coordinate shift occurs due to variations or differences in the shape of the pattern surface during transfer, color blur, etc. Problem occurs.

In order to form a black matrix layer or a color filter layer on the light-transmissive substrate using a photomask, it is most advantageous to apply proximity (proximity) exposure. This is because, as compared with projection (projection) exposure, a complicated optical system is not required for the structure of the exposure machine, and the apparatus cost is low, so the production efficiency is high. However, when the close exposure is applied, it is difficult to correct the distortion at the time of transfer, so that the transfer accuracy tends to deteriorate compared to the projection exposure.

In the close-up exposure, the pattern is transferred to the resist film by holding the transfer target body on which the resist film is formed and the pattern surface of the photomask, keeping the pattern surface downward, and irradiating light from the back surface side of the photomask. At this time, a small gap (proximity gap) is provided between the photomask and the transfer member. Moreover, the photomask is provided with the pattern for transcription | transfer which becomes predetermined patterning on the light shielding film formed in the main surface of a transparent substrate.

In general, when the photomask is set in the exposure exposure apparatus, the support member of the exposure apparatus supports the outside of the region (also referred to as a pattern formation region) on the main surface on which the transfer pattern is formed.

Here, since the photomask mounted on the exposure machine is bent by its own weight, this can be corrected to some extent by the support mechanism of the exposure machine. For example, in the method of patent document 1, it is described that the support member which supports a photomask from below and applying the force of predetermined pressure from the upper side of a mask outside the support point of this support member.

However, it has been found by the inventors that although it is useful to alleviate the influence on the pattern transfer due to the warping of the photomask, it is not sufficient for the manufacture of a precise display device for the above use.

For example, when the above-mentioned close exposure is performed, the accuracy of overlapping the transfer patterns formed on the transfer object is insufficient, although the formation accuracy of the transfer pattern included in the photomask is sufficiently high within the reference range. It has been found that there may be a problem in the operation of the liquid crystal display, a color blur or the like. As the precision of liquid crystal display devices is advanced, deterioration of the overlapping accuracy of such patterns cannot be tolerated.

The present invention improves the transfer accuracy when transferring the transfer pattern formed on the photomask to the transfer target, and can increase the coordinate accuracy over the entire surface of the transfer pattern, the photomask, and the photomask thereof. An object of the present invention is to provide a production method and a pattern transfer method.

According to the first aspect of the present invention,

A photomask substrate having a thickness T (mm) for forming a transfer pattern on a first main surface to form a photomask,

On the second main surface on the back surface of the first main surface, when the elevation difference between any two points 10 (mm) apart is ΔZb (μm), the first corresponding to the pattern formation region of the first main surface A photomask substrate is provided in which ΔZb in the region of the two main surfaces satisfies ΔZb ≦ (1 / T) × 3.0.

According to a second aspect of the present invention,

A photomask having a thickness T (mm) having a transfer pattern formed on a first major surface,

On the second main surface on the back surface of the first main surface, when the elevation difference between any two points 10 (mm) apart is ΔZb (μm), the first corresponding to the pattern formation region of the first main surface A photomask in which ΔZb in the region of the two main surfaces satisfies ΔZb ≦ (1 / T) × 3.0 is provided.

According to the third aspect of the present invention,

The photomask as described in the 2nd aspect which is for proximity exposure is provided.

According to the fourth aspect of the present invention,

The photomask as described in a 2nd or 3rd aspect for color filter manufacture is provided.

According to the fifth aspect of the present invention,

As a method of manufacturing a photomask having a transfer pattern on a first major surface,

The substrate for photomasks having a thickness T (mm), wherein the height difference between any two points 10 (mm) apart on the second main surface on the back surface of the first main surface is ΔZb (μm). ΔZb in the region of the second main surface corresponding to the pattern forming region of the main surface is

ΔZb≤ (1 / T) × 3.0

Prepare a photomask substrate that satisfies the

An optical film is formed on the first major surface of the photomask,

By patterning the optical film, a method of manufacturing a photomask comprising forming a transfer pattern is provided.

According to the sixth aspect of the present invention,

As a method of manufacturing a photomask having a transfer pattern on a first major surface,

A plurality of measuring points are set at equal intervals with a predetermined separation distance P (mm) on the second main surface on the rear surface of the first main surface of the photomask substrate having a thickness T (mm),

When the height Z with respect to the reference surface of the second main surface at each of the plurality of measurement points is obtained, and the difference between the maximum value and the minimum value of the height Z at the plurality of measurement points is set to the maximum value ΔZbmax of the height variation,

ΔZbmax≤ (P / T) × 0.3

Preparing the photomask substrate satisfying the

An optical film is formed on the first main surface of the prepared photomask substrate,

Forming a resist film on the optical film,

The photomask substrate is mounted on a stage of the drawing apparatus to draw a predetermined transfer pattern,

With respect to the photomask substrate after drawing, a method of manufacturing a photomask comprising forming a transfer pattern by performing a resist development and an optical film patterning is provided.

According to the seventh aspect of the present invention,

The separation distance P is 5≤P≤15 (mm)

The manufacturing method of the photomask as described in a 6th aspect is provided.

According to the eighth aspect of the present invention,

The photomask is for proximity exposure

The manufacturing method of the photomask as described in a 5th or 6th aspect is provided.

According to the ninth aspect of the present invention,

The transfer pattern is for producing color filters

The manufacturing method of the photomask as described in any one of 5th-8th aspect is provided.

According to a tenth aspect of the present invention,

In the pattern transfer method which transfers the transfer pattern which a photomask has to a to-be-transferred body using a proxy exposure machine,

The photomask which concerns on the photomask as described in any one of 2nd-4th aspect, or the manufacturing method as described in any one of 5th-9th aspect is exposed by the said proxy exposure machine.

A pattern transfer method is provided.

According to the present invention, it is possible to improve the transfer accuracy at the time of transferring the transfer pattern formed on the photomask to the transfer target, and to increase the coordinate accuracy over the entire surface of the transfer pattern.

1 is a flowchart illustrating an outline of a manufacturing process of a color filter according to the present embodiment.
FIG.2 (a) is a side view which illustrates the mode which performs proximity exposure in the manufacturing process of the color filter which concerns on this embodiment, (b) is the top view.
FIG. 3A is a plan view illustrating a planar configuration of a photomask according to the present embodiment, and FIG. 3B is a plan view illustrating a modification thereof.
4 is a flowchart showing a process for producing a photomask in the case of using a transparent substrate with deformation during drawing and exposure.
FIG. 5 is a view showing a shape change of the transparent substrate at the time of drawing and at the time of exposure. FIG.
6 is a schematic diagram illustrating a state in which flatness is measured by incident laser light.
Fig. 7 is a diagram showing a relationship between overlapping and misalignment of photomasks.
8 is a flowchart illustrating a manufacturing process of a photomask according to the present embodiment.

<One embodiment of the present invention>

EMBODIMENT OF THE INVENTION Below, one Embodiment of this invention is described.

(1) manufacturing process of color filter

First, the manufacturing process of the color filter used for a liquid crystal display device etc. is demonstrated, referring FIGS. 1 is a flowchart illustrating an outline of a manufacturing process of a color filter according to the present embodiment. FIG.2 (a) is a side view which illustrates the mode of performing close-up exposure in the manufacturing process of the color filter which concerns on this embodiment, and FIG.2 (b) is the top view. FIG. 3A is a plan view illustrating a planar configuration of a photomask according to the present embodiment, and FIG. 3B is a plan view illustrating a modification thereof.

As shown in FIG. 1, the color filter 10 for liquid crystal display devices forms the black matrix layer 12p which comprises the boundary of a color on one main surface of the translucent base material 11 (FIG. 1). (A) to (e)] and a red filter layer 14p, a green filter layer 15p, a blue filter layer 16p and the like on one main surface of the light transmissive substrate 11 partitioned by the black matrix layer 12p. It manufactures by performing the process (FIG. 1 (f)-(j) of FIG. 1) which forms a color filter layer one by one. Below, each process is demonstrated.

(Formation of Black Matrix Layer)

First, the light-transmissive base material 11 which consists of a translucent resin, glass, etc. is prepared, the light-shielding material film 12 is formed on one main surface of the light-transmissive base material 11, and the resist film ( 13) (Fig. 1 (a)).

Then, the first photomask 100 for forming the black matrix, and the light-transmitting substrate 11 on which the light shielding material film 12 and the resist film 13 as the transfer target are formed are disposed in the exposure machine 500 for proximity exposure [ 1 (b) and 2].

3A, the first photomask 100 includes a transfer pattern 112p in which a light shielding film formed on a first main surface of the transparent substrate 101 is formed with a predetermined pattern. And a pattern formation region 133 having a structure (hereinafter, the predetermined region to be formed may also be the pattern formation region 133 in addition to the region where the transfer pattern is formed). The shape of the pattern 112p for transfer becomes a grid | lattice form, for example so that the black matrix layer 12p may be formed. In addition, on the first main surface of the transparent substrate 101 of the first photomask 100, two opposite sides constituting the outer circumference of the first main surface of the transparent substrate 101 are formed outside the pattern formation region 133. In each vicinity, there is a support portion 103 in which the support member of the exposure machine is in contact. The light shielding film may be formed in the support part 103, and the 1st main surface of the transparent substrate 101 may be exposed.

As shown in FIG. 2A, the supporting portion 103 is supported from below by the supporting member 503 of the exposure machine 500, so that the first photomask 100 is exposed to the exposure apparatus 500 in a horizontal position. Is disposed within. The transfer pattern 112p included in the first photomask 100 and the resist film 13 formed on the light-transmitting substrate 11 face each other, and are close to, for example, a distance of 10 µm or more and 300 µm or less. Is placed.

The light-transmitting substrate 11, on which the first photomask 100, the light shielding material film 12, and the resist film 13 are formed, is disposed in the exposure machine 500 for proximity exposure. ) And the irradiation system 502, light such as ultraviolet rays are irradiated from the back surface side of the first photomask 100, and the resist film 13 is exposed through the transfer pattern 112p to expose the resist film 13. A part of the photoresist) (FIG. 1C, FIG. 2A). The light source of the wavelength range containing i line | wire to g line | wire can be used for exposure.

And the light transmissive base material 11 after exposure in which the 1st photomask 100 and the light shielding material film 12 and the resist film 13 were formed is isolate | separated from the exposure machine 500. FIG. Then, the resist film 13 is developed to form a resist pattern 13p partially covering the light shielding film (Fig. 1 (d)).

Then, the light shielding material film 12 is etched using the formed resist pattern 13p as a mask to form a black matrix layer 12p on one main surface of the light transmissive substrate 11 (Fig. 1 (e)). . When the black matrix layer 12p is formed, the resist pattern 13p is removed.

(Formation of Red Filter Layer)

Subsequently, a red resist film 14 made of, for example, a photosensitive resin material is formed on one main surface of the light transmissive substrate 11 on which the black matrix layer 12p is formed (FIG. 1F).

The light-transmitting substrate 11 having the second photomask 200 for forming a red filter layer, the black matrix layer 12p as a transfer object, and the red resist film 14 is formed in the above-described exposure machine 500 for proximity exposure. It arrange | positions (FIG. 1 (g)).

As illustrated in FIG. 3A, the second photomask 200 includes a transfer pattern 212p formed by processing a light shielding film on the first main surface of the transparent substrate 201. Equipped. The shape of the transfer pattern 212p becomes a shape for forming the red filter layer 14p, and becomes a shape different from the transfer pattern 112p of the first photomask 100. In addition, on the first main surface of the transparent substrate 201 of the second photomask 200, in the vicinity of each of the two opposite sides forming the outer periphery of the transparent substrate 201 outside the pattern formation region 133, There is a support portion 203 to which the support member of the exposure machine 500 is in contact. The light shielding film may be formed in the support part 203, and the main surface of the transparent substrate 201 may be exposed.

As shown in FIG. 2A, the supporting portion 203 is supported from below by the supporting member 503 of the exposure machine 500, so that the second photomask 200 is exposed to the exposure apparatus 500 in a horizontal attitude. Is disposed within. The transfer pattern 212p of the second photomask 200 and the red resist film 14 formed on the light transmissive substrate 11 face each other and are disposed close to the above-described proxy gap distance.

The light-transmitting substrate 11 on which the second photomask 200 and the black matrix layer 12p and the red resist film 14 are formed is disposed in the exposure machine 500 for proximity exposure, and when position alignment is completed, the light source ( Using the 501 and the irradiation system 502, light such as ultraviolet rays is irradiated from the rear surface side of the second photomask 200, and the red resist film 14 is exposed through the transfer pattern 212p to expose the red resist. A part of the film 14 is exposed (Fig. 1 (h)).

The light transmissive substrate 11 on which the second photomask 200 and the red resist film 14 are exposed is separated from the exposure machine 500. Then, the red resist film 14 is developed, and the remaining red resist film 14 is baked and cured to form a red filter layer 14p (Fig. 1 (i)).

(Formation of Green Filter Layer and Blue Filter Layer)

Subsequently, formation of the green filter layer 15p and the blue filter layer 16p is performed in the same manner as the formation of the red filter layer 14p, and on the main surface of the transparent substrate 11 partitioned by the black matrix layer 12p, the red filter layer ( 14p), the process of forming color filter layers, such as the green filter layer 15p and the blue filter layer 16p, is complete | finished (FIG. 1J).

(Formation of ITO Electrodes)

Although not shown, thereafter, an ITO film is formed so as to cover the top surfaces of color filter layers such as the black matrix layer 12p, the red filter layer 14p, the green filter layer 15p, and the blue filter layer 16p to form a transparent electrode. The manufacture of the filter 10 is complete | finished.

(2) About transfer accuracy of pattern

The transfer pattern of the photomask mentioned above is formed by drawing predetermined pattern data with respect to the resist film formed on the light shielding film as mentioned later. That is, after the drawing process, a resist pattern is formed by image development, and it forms by etching a light shielding film using the resist pattern as a mask. Although the accuracy of the above-described drawing apparatus is sufficiently high, it has been found that the coordinate accuracy of the pattern at the time of transfer is insufficient in the final product, resulting in a positional shift of the black matrix layer or the color filter layer.

According to an example of an inventor or the like, it has been found that such degradation in transfer accuracy is related to the flatness of the second main surface (the back side with respect to the first main surface on which the transfer pattern is formed) of the transparent substrate included in the photomask. It became. Below, the mechanism by which the flatness of the back surface of a transparent substrate affects deterioration of transfer precision is demonstrated, referring FIG. FIG. 4 is a flowchart showing a manufacturing process of the photomask 100 'accompanied with deformation during drawing and exposure when the transparent substrate 101' having insufficient flatness of the second main plane is used.

First, the transparent substrate 101 'is prepared (FIG. 4A). A transfer pattern 112p 'is formed on the first main surface of the transparent substrate 101 (upper surface in Fig. 4A). The first and second major surfaces (surface and back surface) of the transparent substrate 101 'are polished to be flat and smooth, respectively, but the second major surface (the lower surface in Fig. 4A) is It has a convex shape in the upward direction. In addition, the 2nd main surface shape of FIG.4 (a) is an example of the shape for demonstrating the deformation | transformation of a board | substrate.

Subsequently, a light shielding film 112 'containing Cr as a main component is formed on the surface of the transparent substrate 101', and a resist film 113 'is formed on the light shielding film 112'. (B) of FIG. 4]. The transparent substrate 101 'on which the light shielding film 112' and the resist film 113 'are formed is also referred to as a photomask blank 100b'.

Then, the manufactured photomask blank 100b 'is arrange | positioned at the drawing apparatus (laser drawing machine or electron beam drawing machine). At this time, the back surface of the transparent substrate 101 'is mounted on the stage 603 of the drawing apparatus. This causes the photomask blank 100b 'to be horizontal along the loading surface of the stage 603 by its own weight (Fig. 4 (c)). As a result, deformation occurs on the first main surface side of the photomask blank 100b '. In this state, the resist film 113 'is drawn and a part of the resist film 113' is exposed to light (Fig. 4 (d)).

Then, the photomask blank 100b 'by which drawing was completed is isolate | separated from the drawing apparatus. Then, the resist film 113 'is developed to form a resist pattern 113p' (Fig. 4 (e)). Then, a portion of the light shielding film 112 is etched using the resist pattern 113p 'as a mask to form the transfer pattern 112p', thereby completing the photomask 100 '(FIG. 4F).

The above drawing is performed in a state in which the second main surface of the transparent substrate 101 'is supported from below by the stage 603 of the drawing apparatus, that is, in a state where the transparent substrate 101' is deformed. On the other hand, although the photomask blank 100b 'which is completed drawing is isolate | separated from the drawing apparatus, the deformation | transformation of the above-mentioned transparent substrate 101' is eliminated at this time.

As a result, even when the above-described drawing accuracy of the resist film 113 'is sufficiently high, the shape of the first main surface of the transparent substrate 101' when the transfer pattern is drawn and the formation of the transfer pattern The shape of the first main surface when the photomask is set in the exposure machine is different, and the coordinates on the first main surface are shifted from each other by this shape change. That is, the deviation of this coordinate is due to the flatness of the second main surface on which the transfer pattern is not formed.

The inventors made intensive research based on the above-mentioned considerations. As a result, in order to improve the transfer accuracy of a pattern, the said transparent deformation | transformation of the transparent substrate at the time of loading in the stage of a drawing apparatus shall be within the range which can control the coordinate shift at the time of pattern transfer within an allowable range. It turned out that it was necessary to prepare.

The shift | offset | difference amount d of the coordinate shift | offset | difference by the said deformation | transformation of a transparent substrate is as showing in FIG. That is, when the transparent substrate having a thickness of T (mm) is bent at an angle θ, the horizontal shift amount d generated in the coordinates on the main surface is d = (T × 10 ³ ) / 2 × sinθ (μm). . What is necessary is just to control so that the numerical value of this d may be within the allowable range of the coordinate shift which is allowed for the final product.

By the way, the device pattern of a liquid crystal display device is refine | miniaturized. The black matrix (BM) used for the color filter also has a particularly strong demand for thinning. In the past, the BM width, which has been considered as sufficient as about 10 μm, is expected to be about 8 μm or 6 μm in recent years, and the difficulty of manufacturing technology is further increased.

For example, consider a case where a BM of 6 mu m or less is to be formed (Fig. 7 (a)). When the color plates are superimposed on the BM, the maximum value of the coordinate shift allowed on one side (for example, on the BM) is 3 µm (Fig. 7 (b)). This is because if the boundary between color plates (for example, red and blue) is out of the width of the BM, problems such as color blurring occur. In addition, considering that there is a line width error of the color plate itself and that there is a line width error of the BM itself, one coordinate shift should be within (3 μm × 1/2 × 1/2 =) 0.75 μm [Fig. 7 (c)].

By the way, drawing reproducibility which a writing apparatus has is about 0.15 micrometer, and the margin on the photomask substrate side is (0.75-0.15 =) 0.60 micrometer. This is the allowable value of the coordinate shift caused by the photomask (Fig. 7 (d)).

However, the factor of the coordinate shift caused by the photomask substrate is not only due to the flatness of the photomask second main surface. According to the inventors' studies, there are a plurality of factors, which are significant (not negligible as factors), and in addition, distortion of the transfer pattern due to contact between the support member of the exposure machine and the photomask, and the first There are factors such as the flatness of the main surface.

Therefore, in order to distribute the allowable coordinate shift amount to the above-mentioned three main factors (FIG. 7 (e)), and to satisfy Cpk (Processability Index) 1.3, it is caused by the height variation of the pattern formation area. The allowable shift | offset | difference amount to make shall be 0.15 micrometer or less in the photomask of a single piece.

Here, in the 2nd main surface of the transparent substrate which is thickness T (mm), when the height difference of arbitrary two points spaced apart P (mm) is (DELTA) Zb (micrometer), as mentioned above, the shift amount d (micrometer) Is

d = (T × 10 ³ ) / 2 × sinθ (μm)

((Theta) is the bending angle of the transparent substrate shown in FIG. 5).

Also,

sinθ = ΔZb / (P × 10 ³ )

As I can approximate with

0.15 (μm) ≥ d = (T × 10 ³ ) / 2 × [ΔZb / (P × 10 ³ )]

This holds true.

therefore,

ΔZb≤ (P / T) × 0.3

to be.

If P = 10 mm,

ΔZb≤ (1 / T) × 3.0

to be.

That is, in the area | region corresponding to the pattern formation area | region of a 1st main surface as a 2nd main surface of a transparent substrate, if it is a transparent substrate which satisfy | fills (DELTA) Zb <(1 / T) * 3.0, the board | substrate deformation at the time of drawing and exposure will be carried out. Even if the coordinate shift | offset | difference which originates in is made, it can be set as it does not affect the performance of a final product.

In addition, although the space | interval distance P of two points was made into 10 mm above, the value of P can be made into the space | interval distance of a measurement point at the time of measuring the height of the point on a 2nd main surface by the method mentioned later.

The measurement point can be set to any position in the region on the second major surface corresponding to the pattern transfer region of at least the first major surface.

In addition, the measurement point includes a region corresponding to the pattern transfer region, and is set to a wider region (hereinafter also referred to as the measurement region 143).

ΔZb≤ (P / T) × 0.3

It is preferable to make it satisfy.

The measurement region may include at least a region corresponding to the pattern transfer region on the second main surface of the rectangular transparent substrate. Preferably, it can be set as the area | region except the area | region of 20 mm from an outer edge in the vicinity of the four sides used as the outer edge of the said transparent substrate. In the area, when any two points spaced apart by the separation distance P are set,

ΔZb≤ (P / T) × 0.3

Lt; / RTI &gt;

Moreover, when the support part 103 which the support member of the exposure machine contacts is at the 2nd main surface at the time of exposure, it is preferable to make the said measurement area into the area containing the support part. In this case, for example, it is more preferable that the measurement region is such that the inequality of ΔZb is satisfied in the region excluding the region of 10 mm from the outer edge as the vicinity of the four sides serving as the outer edge of the second main surface.

That is, by making flatness of the back surface of a transparent substrate into the above-mentioned range, the deformation | transformation of the transparent substrate at the time of installing a photomask blank in a drawing machine can be suppressed, and, thereby, of the transfer pattern of the photomask provided in an exposure machine Deformation can be suppressed and the knowledge that the transfer precision of a pattern can be improved was acquired.

(3) Manufacturing method of photomask

Hereinafter, the manufacturing method of the photomask which concerns on this embodiment to which the above-mentioned knowledge was applied is demonstrated, referring FIG. 5, FIG. It is a figure which shows the shape change of the transparent substrate at the time of drawing and the exposure. 6 is a schematic diagram illustrating how flatness is measured by incident laser light. In addition, in the following description, although the case where the 1st photomask 100 for black matrix formation is manufactured is demonstrated as an example, manufacture of the 2nd thru | or 4th photomask for color filter layer formation also demonstrates a 1st photomask ( It can carry out similarly to manufacture of 100).

(Preparation of Transparent Substrate and Inspection of Flatness)

First, the transparent substrate 101 is prepared (FIG. 8A). In addition, as illustrated in FIG. 3A, the transparent substrate 101 has a rectangular plate shape in plan view, and the dimension thereof is, for example, 600-1400 mm long side L1 and short side L2. 500-1300 mm and thickness T may be about 5 to 13 mm. The transparent substrate 101 can be made of, for example, quartz (SiO ₂ ) glass, low expansion glass containing SiO ₂ , Al ₂ O ₃ , B ₂ O ₃ , RO, R ₂ O, or the like. Of the main surfaces of the transparent substrate 101, the main surface of the side which forms the transfer pattern 112p is made into the 1st main surface. Here, the area where the transfer pattern is to be formed is set. In addition, a long side is formed inside each of the two adjacent sides (long side L1 in the present embodiment) that constitute the outer periphery of the transparent substrate 101 as the outside of the region to be formed of the transfer pattern 112p. A pair of strip | belt-shaped support parts 103 parallel to L1 are provided, respectively. For example, the support part 103 is a straight line 10 mm apart from each of the opposing long sides L1 constituting the outer periphery of the first photomask 100, and 50 mm from each of the long sides L1. It can be comprised as a pair of strip | belt-shaped area | region parallel to the long side L1 sandwiched between one straight line.

As described later, the height difference (µm) can be measured using a planar measuring instrument, and when the flatness of the present embodiment is obtained, the height difference (µm) can be obtained using a reference plane defining the device. In addition, when measuring the height difference, it is preferable to make a board | substrate perpendicular and to perform it in the situation which removed the influence of the curvature by self weight substantially.

The setting of the positions of two points for obtaining the height difference is as described above.

If the distance P between two points is small, it is possible to grasp the shape change in the minute region of the second main surface, but the larger the area of the transparent substrate, the larger the measurement point becomes, and the efficiency leading to the determination of the quality of the substrate This goes down. When P is too big | large, the reference | standard of the flatness of a 2nd main surface will loosen and the transparent board | substrate which is easy to produce a coordinate shift will be allowed.

Preferably, P is set to 5 ≦ P ≦ 15 (mm). More preferably, it can be P = 10 mm.

For example, flatness can be calculated | required using each lattice point when the whole measurement area is divided | segmented into the grid | lattices of Pmm (for example, 10 mm) width as a measuring point, and using the height difference of adjacent measuring points. That is, the arbitrary two points in the present invention mean that each lattice point when the area (or measurement area) on the second main surface corresponding to the pattern formation area is divided into a lattice having a width of P mm as a population. It may be any two points spaced apart from each other by Pmm.

The first and second major surfaces of the transparent substrate 101 are flat and smooth, respectively, by polishing. In addition, the flatness of the 2nd main surface of the transparent substrate 101 shall satisfy | fill a standard with respect to arbitrary two points determined by the said method. That is, in at least the second main surface corresponding to the pattern formation region,

ΔZbmax (μm) ≤ (P / T) × 0.3

to be. Moreover, it is preferable that this relationship is satisfied in the above-mentioned measurement area.

If P = 10 mm,

ΔZbmax (μm) ≦ (1 / T) × 3.0

to be.

Whether or not the flatness of the second main surface satisfies the above-described requirements is, for example, as shown in FIG. Can be inspected. For example, it can carry out using the planar measuring device FFT-1500 (trademark) made from Kuroda Corporation, and the thing of Unexamined-Japanese-Patent No. 2007-46946.

(Formation of light shielding film and resist film)

Then, the light shielding film 112 which has Cr as a main component is formed on the main surface of the transparent substrate 101, for example. The light shielding film 112 can be formed by methods, such as sputtering and vacuum deposition, for example. The thickness of the light shielding film 112 is a thickness sufficient to block the irradiation light of the exposure machine 500, and can be, for example, about 100 to 120 nm. In addition, on the upper surface of the light shielding film 112, an antireflection layer containing, for example, CrO as a main component can be formed. In addition, when setting the support part 103 to a 1st main surface, the light shielding film 112 does not need to be formed on the support part 103. FIG.

In addition, in this aspect, although it demonstrates using the thing with a light shielding film as a transfer pattern formed in a photomask, you may use optical films (such as the semi-transmissive film which has a predetermined light transmittance) other than a light shielding film.

Then, a resist film 113 is formed on the light shielding film 112 (FIG. 8B). The resist film 113 can be made of a positive photoresist material or a negative photoresist material. In the following description, it is assumed that the resist film 113 is formed of a positive photoresist material. The resist film 113 can be formed, for example, by a method such as spin coating or slit coating. The transparent substrate 101 on which the light shielding film 112 and the resist film 113 are formed is also referred to as a photomask blank 100b hereinafter.

(Drawing process)

Then, the manufactured photomask blank 100b is arrange | positioned at the drawing apparatus. At this time, the 2nd main surface of the transparent substrate 101 is supported from below by the upper surface of the stage 603 with which the drawing apparatus is equipped, and the photomask blank 100b is made horizontal. Subsequently, the resist film 113 is drawn to expose a portion of the resist film 113. Moreover, although the upper surface of the stage 603 is comprised flat, since the flatness of the 2nd main surface of the transparent substrate 101 exists in the above-mentioned range, the transparent substrate 101 itself differs from the case mentioned above. It is hardly deformed by weight.

(Developing, etching process)

Subsequently, the photomask blank 100b on which the drawing is completed is separated from the drawing apparatus. Then, the developer is supplied to the resist film 113 and developed to form a resist pattern 113p covering a part of the light shielding film 112 (Fig. 8 (c)).

A part of the light shielding film 112 is etched using the formed resist pattern 113p as a mask. The etching of the light shielding film 112 can be performed by supplying etching liquid on the light shielding film 112. As a result, the transfer pattern 112p in which the light shielding film 112 is patterned is formed on the surface of the transparent substrate 101 (FIG. 8D). Then, the resist pattern 113p is removed to complete the manufacture of the first photomask 100 (FIG. 8E).

In addition, since the shape of the photomask blank and photomask produced using the transparent substrate of this invention is substantially maintained, the numerical value of (DELTA) Zb can also be in the same range as the transparent substrate of this invention.

Although the above-mentioned drawing is performed in the state which supported the 2nd main surface of the transparent substrate 101 from below by the stage 603, the flatness of the 2nd main surface of the transparent substrate 101 will be in the above-mentioned range. Therefore, the shape change of the 1st main surface resulting from the deformation | transformation of the transparent substrate 101 by its own weight during drawing is suppressed. Therefore, in the transfer pattern 112p formed on the surface of the transparent substrate 101, even when the 1st photomask 100 is provided in the exposure apparatus 500 mentioned above, the coordinate shift resulting from the said deformation | transformation is suppressed. . And the transfer precision of the pattern mentioned above can be improved.

<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.

For example, the support part is not limited to the case where a pair is provided like embodiment mentioned above, and many support parts may be provided along the circumference | surroundings of a photomask. That is, as shown in (b) of FIG. 3, the outer circumference of the transparent substrates 101 and 201 as an outer side of the pattern formation region 133 on one main surface of the transparent substrates 101 and 201 which are rectangular in plan view. Four strip | belt-shaped support parts 103 and 203 may be provided in the area | region of each vicinity of the four sides L1 and L2 which comprise this. For example, the four support parts 103 and 203 are the outer side of the pattern formation area 133, and the straight line which separated 10 mm from each of four sides which comprise the outer periphery of the photomask 100 and 200, and each of four sides It can be comprised as four strip | belt-shaped area | regions parallel to each of four edge | intervals sandwiched between the straight lines 50 mm apart from the inside. In addition, the support parts 103 and 203 may be in the 2nd main surface side of a transparent substrate.

In addition, the black matrix layer 12p is not limited to having a metal material such as Cr as a main component, and may be formed of a photosensitive resin having light shielding properties. When using photosensitive resin, the black matrix layer 12p can be formed by performing exposure, image development, and baking one by one like a color filter layer.

100: first photomask
101: transparent substrate
112p: Transfer pattern
200: second photomask
201: transparent substrate
212p: Transfer pattern
603 stage

Claims (10)

A photomask substrate having a thickness T (mm) for forming a transfer pattern on a first main surface to form a photomask,
The second corresponding to the pattern formation region of the first major surface when the elevation difference of any two points 10 (mm) apart from the second major surface on the rear surface of the first major surface is ΔZb (μm); ΔZb in the region of the main surface
A photomask substrate, which satisfies ΔZb ≦ (1 / T) × 3.0. A photomask having a thickness T (mm) having a transfer pattern formed on a first major surface,
The second corresponding to the pattern formation region of the first major surface when the elevation difference of any two points 10 (mm) apart from the second major surface on the rear surface of the first major surface is ΔZb (μm); ΔZb in the region of the main surface
A photomask that satisfies ΔZb ≦ (1 / T) × 3.0. The method of claim 2,
A photomask for proximity exposure. The method of claim 2,
A photomask for producing color filters. As a method of manufacturing a photomask having a transfer pattern on a first major surface,
The substrate for photomasks having a thickness T (mm), wherein the height difference between any two points 10 (mm) apart on the second main surface on the back surface of the first main surface is ΔZb (μm). ΔZb in the region of the second main surface corresponding to the pattern forming region of the main surface is
ΔZb≤ (1 / T) × 3.0
Prepare a photomask substrate that satisfies the
An optical film is formed on the first major surface of the photomask,
Forming a pattern for a transfer by patterning the said optical film, The manufacturing method of the photomask characterized by the above-mentioned. As a method of manufacturing a photomask having a transfer pattern on a first major surface,
A plurality of measuring points are set at equal intervals with a predetermined separation distance P (mm) on the second main surface on the rear surface of the first main surface of the photomask substrate having a thickness T (mm),
The height Z with respect to the reference surface of the second main surface at the plurality of measurement points is obtained, respectively,
When the difference between the maximum value and the minimum value of the height Z at the plurality of measurement points is taken as the maximum value ΔZbmax of the height variation,
ΔZbmax≤ (P / T) × 0.3
Preparing the photomask substrate satisfying the
An optical film is formed on the first main surface of the prepared photomask substrate,
Forming a resist film on the optical film,
The photomask substrate is mounted on a stage of the drawing apparatus to draw a predetermined transfer pattern,
A method of manufacturing a photomask, comprising forming the transfer pattern by subjecting the photomask substrate after drawing to resist development and patterning of an optical film. The method of claim 6,
The separation distance P is 5? P? 15 (mm). The method according to claim 5 or 6,
The photomask is a method of manufacturing a photomask, characterized in that for proximity exposure. The method according to claim 5 or 6,
The said transfer pattern is for manufacturing a color filter, The manufacturing method of the photomask characterized by the above-mentioned. In the pattern transfer method which transfers the transfer pattern which a photomask has to a to-be-transferred body using a proxy exposure machine,
The pattern transfer method which exposes the photomask as described in any one of Claims 2-4 with the said proxy exposure machine.

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