KR20180103743A - Photomask for use in manufacturing a display device and method of manufacturing a display device - Google Patents

Abstract

Provided is a photomask for manufacturing a display device, capable of stably forming a fine hole pattern on a transcribed body. The photomask is a photomask for manufacturing a display device having a pattern for transcription on a transparent substrate. The pattern for transcription comprises a main pattern composed of a rectangular light-transmitting part; an auxiliary pattern composed of a phase shift part arranged around the main pattern; and a low light-transmitting part formed in the other area. When a regular octagonal band having a predetermined width surrounding the main pattern is defined around the main pattern, the auxiliary pattern forms at least a part of the regular octagonal band. When one of a plurality of main patterns included in the pattern for transcription is used as a first main pattern, a second main pattern different from the first main pattern is disposed at a position adjacent to the first main pattern. Among eight sections constituting the regular octagonal band surrounding the first main pattern, an auxiliary pattern having a deficit in at least one section facing the second main pattern side is arranged around the first main pattern.

Description

TECHNICAL FIELD [0001] The present invention relates to a photomask for manufacturing a display device, and a manufacturing method of the display device. BACKGROUND OF THE INVENTION 1. Field of the Invention [0002]

The present invention relates to a photomask suitable for use in manufacturing a display device (flat panel display: FPD) as a photomask for manufacturing an electronic device.

Patent Document 1 discloses a photomask which is suitable for an exposure environment of a mask for manufacturing a display device and is capable of stably transferring a fine pattern.

Patent Document 2 discloses a method for simultaneously miniaturizing an isolated pattern and a dense pattern with respect to a photomask for forming a fine pattern used for manufacturing a semiconductor integrated circuit device.

(Patent Document 1) Japanese Patent Application Laid-Open No. 2016-024264 (Patent Document 2) Japanese Patent Application Laid-Open No. 2006-338057

A display device including a liquid crystal display or an organic EL (Organic Electroluminescence) display device is required to have a brighter, lower power and improved display performance such as a high-precision, high-speed display and a wide viewing angle .

For example, in the case of a thin film transistor (TFT) used in the display device, among the plurality of patterns constituting the TFT, the contact holes formed in the interlayer insulating film surely connect the patterns of the upper layer and the lower layer Otherwise, correct operation is not guaranteed. On the other hand, for example, in order to make a display device having a bright and low power by increasing the aperture ratio of a liquid crystal display device to the maximum, a diameter of the contact hole is required to be sufficiently small. (For example, less than 3 mu m). For example, it is considered that a hole pattern having a diameter of 0.8 μm or more and 2.5 μm or less, furthermore, a diameter of 2.0 μm or less is required, and concretely, a pattern having a diameter of 0.8 to 1.8 μm is also required .

However, in the field of a photomask for manufacturing a semiconductor device (LSI) in which the degree of integration is higher than that of a display device and the pattern is made finer, the exposure apparatus is required to have a high numerical aperture NA ), And there is a tendency that the exposure light is shortened in wavelength. As a result, excimer lasers of KrF and ArF (single wavelength of 248 nm and 193 nm, respectively) have become widely used in this field.

On the other hand, in the field of lithography for manufacturing a display device, it is not general that the above technique is applied for improving the resolution. For example, the NA (numerical aperture) of an optical system of an exposure apparatus used in this field is in the range of 0.08 to 0.12, and even in the future, it is in an environment of 0.20 or less, for example, about 0.08 to 0.15. Also, by using a broad wavelength light source mainly including the i-line, the h-line, or the g-line widely used as the exposure light source, the amount of light for irradiating a large area is obtained and the production efficiency and cost tend to be emphasized.

Also, in the manufacture of display devices, there is an increasing demand for miniaturization of patterns as described above. Here, there are some problems in applying the technology for manufacturing semiconductor devices directly to the manufacture of display devices. For example, a large facility investment is required for switching to a high-resolution exposure apparatus having a high numerical aperture (NA), so that the compatibility with the price of the display device can not be obtained. In addition, when the exposure wavelength is changed (a short wavelength such as an ArF excimer laser is used as a single wavelength) to a display device having a large area, not only the production efficiency is lowered but also a considerable facility investment is required It is inappropriate. That is, pursuing miniaturization of a pattern that is not available in the prior art, the conventional merit cost and efficiency can not be lost, which is a problem of a photomask for manufacturing a display device.

The present inventors have proposed a photomask having an auxiliary pattern composed of a main pattern made of a light transmitting portion and a phase shift portion shifting the phase of light having a predetermined wavelength disposed in the vicinity thereof and a low light transmitting portion formed in the other region One). This photomask can be advantageously used to stably form fine isolation holes on a substrate such as a display panel substrate.

On the other hand, as the configuration of the display device becomes more complicated, the design of the transfer pattern becomes complicated, and the inventor has found a new problem that can not be sufficiently solved even by using the photomask described in Patent Document 1. For example, when a plurality of hole patterns are arranged at a predetermined short distance on the transferred body to form a dense pattern, the auxiliary patterns of the respective main patterns approach each other in the transfer pattern on the photomask. In this case, there is a risk that the transmitted light of the auxiliary pattern, which is not originally intended for transfer, loses the thickness of the resist on the transferred body and hinders the formation of a desired transferred image. Here, the dense pattern refers to a pattern in which two or more hole patterns are arranged close to each other on a surface to be transferred, and accordingly, two or more main patterns are arranged close to each other on the photomask. A pattern disposed in proximity is a pattern in which the hole forming pattern on the photomask under the exposure environment has an optical effect on each other. In the specification of the present application, the pattern is sometimes referred to as a pattern arranged closer to the main pattern, including the case where the auxiliary patterns adjacent to the main pattern are located closer to each other.

Patent Document 2 discloses a photomask used for manufacturing a semiconductor integrated circuit device by exposure in a reduced projection exposure system using a ring-shaped band illumination. In the case of the pattern having the outline shifter surrounding the opening, when the interval between the outline shifters corresponding to each of the neighboring patterns becomes small, by joining the outline shifters with each other, . More specifically, as shown in Fig. 15, when four perimeter shifters 711, 712 and 713 surround the perimeter of the opening patterns 721, 722 and 723, the opening pattern 722 and the opening pattern 723 are small, the outline shifter 714 becomes an outline shifter that is shared by both the opening pattern 722 and the opening pattern 723. The photomask disclosed in Patent Document 2 is said to be useful because it can simultaneously miniaturize an isolated space pattern, an isolated line pattern, or a dense pattern.

However, according to the study by the present inventors, it has been confirmed that the technique described in Patent Document 2 is not necessarily useful for a photomask for manufacturing a display device.

Accordingly, it is an object of the present invention to provide a photomask for manufacturing a display device capable of stably forming a minute hole pattern on a transferred body when a display device is manufactured.

(First embodiment)

According to a first aspect of the present invention,

A photomask for manufacturing a display device having a transfer pattern on a transparent substrate,

Wherein the transfer pattern

A main pattern made of a rectangular light transmitting portion,

An auxiliary pattern composed of a phase shift portion disposed in the periphery of the main pattern,

And a low light-transmitting portion formed in a region other than the main pattern and the auxiliary pattern,

Wherein when defining a regular octagonal band of a predetermined width surrounding the main pattern in the vicinity of the main pattern, the auxiliary pattern constitutes at least a part of the regular octagonal band,

Wherein when one of the plurality of main patterns included in the transfer pattern is a first main pattern, a second main pattern different from the first main pattern is disposed at a position approaching the first main pattern,

An auxiliary pattern having a missing portion in one section facing the second main pattern among the eight sections constituting the regular octagonal band surrounding the first main pattern is disposed around the first main pattern And a photomask for manufacturing a display device.

(Second Aspect)

In a second aspect of the present invention,

Wherein the transfer pattern forms a hole pattern having a diameter W2 (W1? W2) as a transfer image of the main pattern on the transfer object when the diameter of the main pattern is W1. 1 is a photomask for manufacturing a display device.

(Third aspect)

In a third aspect of the present invention,

Wherein the dimension in the X direction of the first main pattern is smaller than the dimension in the Y direction perpendicular to the X direction when the arrangement direction of the first main pattern and the second main pattern is the X direction. 1 or the photomask for manufacturing a display device according to the second aspect.

(Fourth aspect)

According to a fourth aspect of the present invention,

Wherein the transfer pattern includes a densestion pattern in which at least three of the main patterns are regularly arranged in the X direction, the Y direction perpendicular to the X direction, or the X direction and the Y direction, and the main pattern Is a photomask for manufacturing a display device according to any one of the first to third aspects, wherein each of the eight sections has the auxiliary pattern missing at least one section facing the other main pattern side.

(Fifth aspect)

In a fifth aspect of the present invention,

Wherein the phase shifting portion has a phase shift film which shifts the phase of the exposure light by about 180 degrees and has transmittance of 20 to 80% with respect to the representative wavelength of the exposure light on the transparent substrate. 4 is a photomask for manufacturing a display device according to any one of the aspects of Figs.

(Sixth aspect)

In a sixth aspect of the present invention,

The low-light-transmitting portion is a photomask for manufacturing a display device according to any one of the first to fifth aspects, wherein the optical density OD for the exposure light is a light-shielding portion of two or more.

(Seventh Embodiment)

According to a seventh aspect of the present invention,

A step of preparing a photomask according to any one of the first to sixth aspects,

The transfer pattern is exposed using an exposure apparatus having an exposure number NA of 0.08 to 0.15 and an exposure light source including at least one of i line, h line and g line, And forming a hole pattern having a width W2 of 0.8 to 3.0 (μm).

According to the present invention, when a display device is manufactured, fine hole patterns can be stably formed on a body to be inspected.

1 (a) is a schematic plan view, and FIG. 1 (b) is a sectional schematic view at a position A-A of FIG. 1 (a).
2 (a) to 2 (c) are plan views showing patterns of photomasks of Reference Examples 1 to 3.
Fig. 3 is a diagram showing the results of the simulations of Reference Examples 1 to 3; Fig.
4 is a plan view showing a case where the main patterns of Reference Example 3 are arranged close to each other.
5A is a plan view illustrating a case where the first main pattern and the second main pattern are sufficiently spaced apart from each other, and FIG. 5B is a cross-sectional view illustrating the structure of a resist pattern formed on the transferred body in that case .
FIG. 6A is a plan view illustrating a case where the second main pattern approaches the first main pattern, and FIG. 6B is a cross-sectional view illustrating the structure of the resist pattern formed on the transferred body in that case .
FIG. 7 is a plan view schematically showing a main portion of a transfer pattern provided in a photomask for manufacturing a display device according to an embodiment of the present invention. FIG. 7 (b) to be.
8 is a plan view showing an example in which auxiliary patterns arranged around the main pattern are divided into eight sections.
9 is a cross-sectional view illustrating the structure of a resist pattern to be formed on a transfer body when a transfer pattern of a photomask according to an embodiment of the present invention is applied.
10 (a) to 10 (e) are plan views showing patterns of photomasks of Reference Examples 4 to 8.
11 (f) to 11 (i) are plan views showing the patterns of the photomasks of Examples 1 to 4.
12 is a diagram showing simulation results of a reference example and an embodiment in the embodiment of the present invention.
13 is a plan view showing an example of a transfer pattern of a photomask including a main pattern imparted with a mask bias? 2.
14A to 14F are process drawings for explaining an example of a manufacturing method of a photomask applicable to the embodiment of the present invention.
15 is a plan view showing the pattern of the photomask described in Patent Document 2. Fig.

[Design of photomask for forming hole pattern having auxiliary pattern]

Fig. 1 is a schematic plan view of a transfer pattern of a photomask disclosed in Patent Document 1. Fig. 1 (a) is a schematic plan view and Fig. 1 (b) is a sectional schematic view at a position A-A in Fig.

The transfer pattern of the photomask shown in the figure has a main pattern 1 made of a light transmitting portion and an auxiliary pattern 2 surrounding the main pattern 1 in the periphery thereof. The auxiliary pattern 2 is disposed around the main pattern 1 in association with the main pattern 1. [

On the transparent substrate 10, a phase shift film 11 and a low light transmittance film 12 are formed. The auxiliary pattern 2 is formed on the phase shift layer 5 where the phase shift film 11 on the transparent substrate 10 is exposed, . Further, the low light-transmissive portion 3 surrounds the main pattern 1 and the auxiliary pattern 2, respectively.

The low light transmissive portion 3 is composed of a laminated film of a phase shift film 11 and a low light transmittance film 12 formed on a transparent substrate 10. The low light transmissive portion 3 may be constituted by a single layer film of the low light transmissive film 12 formed on the transparent substrate 10. That is to say that the low light transmissive portion 3 is a portion where at least the low light transmissive film 12 is formed . In the transfer pattern shown in the figure, the area other than the area where the main pattern 1 and the auxiliary pattern 2 are formed is the low light-transmissive part 3.

The phase shift film 11 has a phase shift amount for shifting the exposure light of the representative wavelength in the wavelength range of i line to g line by approximately 180 degrees. That is, the auxiliary pattern 2 has the function of inverting the phase of the transmitted light by the phase shift film 11. Further, with respect to the exposure light of the representative wavelength, the phase shift film 11 has a transmittance of T1 (%).

According to Patent Document 1, an optical simulation for forming a hole pattern on a transferred body is performed using a photomask having the transfer pattern. However, in comparison with a phase shift mask having no binary mask or auxiliary pattern, , It has been found that excellent performance is exhibited in Eop (amount of exposure light necessary for forming a pattern of a target dimension on a transferred body) and DOF (Depth of Focus).

To form a finer pattern on the transferred object, the present inventors performed optical simulation on the photomask shown in Figs. 2 (a) to 2 (c). Here, the photomask of FIG. 2A is referred to the photomask shown in Reference Example 1 and the photomask shown in FIG. 2B is referred to the reference example 2, and the photomask shown in FIG. Then, each of the photomasks of Reference Examples 1 to 3 having a main pattern of a hole pattern having a diameter W1 of 2.0 m was used to form a positive photoresist of a diameter W2 (herein, 1.5 mu m) hole pattern on the surface of the substrate.

In addition, as described above, the diameter W1 of the photomask is set to W1? W2 (preferably W1> W2) with respect to the target diameter W2 of the transferred object. Here, when the mask bias? 1 (?) Is? 1 = W1-W2, here? 1 is 0.5 (占 퐉).

The conditions of the simulation are as follows.

(Reference Example 1)

In Reference Example 1, as shown in Fig. 2A, a photomask made of a binary mask is used to form a hole pattern consisting of a square light transmitting portion surrounded by a low light-transmissive portion (light-shielding portion) 3 and having a diameter W1 = Pattern (1).

(Reference Example 2)

In Reference Example 2, as shown in Fig. 2 (b), a photomask comprising a halftone type phase shift mask was used to form a phase shift portion 5 surrounded by a phase shift portion 5 having a transmittance of exposure light of 5.2% And a hole pattern made of a square translucent portion of W1 = 2 mu m was used as the main pattern 1.

(Reference Example 3)

In Reference Example 3, as shown in Fig. 2 (c), a photomask made of a phase shift mask including an auxiliary pattern is used to form a hole pattern composed of a square translucent portion having a diameter of W1 = 2 m as a main pattern 1 And the auxiliary pattern 2 of the regular octagonal band surrounds the periphery. The auxiliary pattern 2 is constituted by a phase shifting portion having an exposure light transmittance of 45% and a phase shift amount of 180 degrees. A region other than the main pattern 1 and the auxiliary pattern 2 has a lower light- (Light shielding part) (3). The distance L between the center of the main pattern 1 and the center position in the width direction of the auxiliary pattern 2 is 3.25 m and the width d of the auxiliary pattern 2 is 1.3 m. The photomask of Reference Example 3 was designed based on the structure described in Patent Document 1. [

Hole patterns having a width W2 = 1.5 mu m were formed on the transferred body by using the respective photomasks corresponding to the above Reference Examples 1 to 3. [

The exposure conditions of the simulation are as follows.

The optical system of the exposure apparatus has a numerical aperture NA of 0.1 and a coherence factor sigma of 0.5. A light source (broad wavelength light source) including all of i-line, h-line, and g-line was used as an exposure light source, and the intensity ratio was g: h: i = 1: 1: 1.

The optical evaluation items of the photomask are as follows.

(1) depth of focus (DOF)

When a defocus occurs at the time of exposure, the depth of focus is such that the CD fluctuation with respect to the target CD is within a predetermined range (for example, +/- 10%) on the transferred body, and the numerical value is preferably large Do. If the numerical value of the DOF is high, it is difficult to be influenced by the flatness of the transferred body (for example, a display panel substrate), and a fine pattern can surely be formed, and the CD deviation is suppressed. In the present simulation, the target CD ± 10% is used as the value of the DOF. Here, CD stands for Critical Dimension and is used for the meaning of the pattern width. Since the photomask for manufacturing a display device is larger in size than a photomask for manufacturing a semiconductor device and the transferred body (a display panel substrate or the like) is also a large size, it is difficult to complete the flatness in either case. The significance of the photomask which can be increased is great.

(2) Mask Error Enhancement Factor (MEEF)

Is a numerical value representing the ratio of the CD error of the pattern formed on the transferred body to the CD error on the photomask. The lower the MEEF, the CD error of the pattern formed on the transferred body can be reduced. It is highly likely that the MEEF will be important in the future for a display device manufacturing photomask because the specification of the display device needs to evolve and the pattern must be finer and a photomask having a pattern with a dimension close to the resolution limit of the exposure apparatus is required .

(3) Eop

Eop (hereinafter, also referred to as "Eop Dose") is an especially important evaluation item in the photomask for manufacturing a display device. Eop is the amount of exposure light necessary to form the pattern size to be obtained on the subject. The photomask used in the manufacture of the display device is very large in size (for example, a side of the main surface is a square or a rectangle of 300 to 2000 or so). Therefore, if a photomask having a low Eop value is used, the speed of the scan exposure can be increased, and the production efficiency is improved.

Fig. 3 shows the results of the evaluation of the evaluation items.

First, paying attention to Eop, the photomask of Reference Example 3 has an exposure amount (Eop value) of 30% or less for obtaining a hole pattern of a target dimension, as compared with the photomasks of Reference Examples 1 and 2. Therefore, it can be seen that high production efficiency can be obtained by using the photomask of Reference Example 3. In addition, the photomask of Reference Example 3 has a higher DOF value and a lower MEEF value than the photomask of Reference Example 1 and Reference Example 2. Therefore, it can be seen that the photomask of Reference Example 3 is also very advantageous for DOF and MEEF.

[Design of hole patterns at positions approaching each other]

On the other hand, if the resolution required for the display device is increased, the degree of integration is increased by increasing the number of pixels per unit area. Therefore, it is necessary to arrange a plurality of main patterns (hole patterns) closer to each other as a transfer pattern of the photomask for manufacturing a display device. Hereinafter, the case where the photomask of Reference Example 3 is applied to formation of a dense pattern including a plurality of main patterns will be examined.

Fig. 4 shows a case where the pattern applied in Reference Example 3 (a main pattern and an auxiliary pattern formed around the main pattern are combined to be referred to as a pattern for hole formation in the present specification) are arranged close to each other. Here, one of the two main patterns is referred to as a first main pattern 1a and the other is referred to as a second main pattern 1b. When the position of the second main pattern 1b is approached in the direction of the arrow with respect to the first main pattern 1a, the hole pitch P, which is the distance between the centers of the two main patterns 1a and 1b, Consider the cross-sectional shape of the formed resist pattern.

5 (a), when the first main pattern 1a and the second main pattern 1b are sufficiently spaced (P = 12 μm), as shown in FIG. 5 (b) Hole patterns 21a and 21b corresponding to the main patterns 1a and 1b are formed in a resist pattern 20 (a pattern made of a positive type photoresist in this case) on the transfer target body.

On the other hand, as shown in Fig. 6A, when the second main pattern 1b approaches (P = 8 m) to the first main pattern 1a, the peripheral portions of the main patterns 1a and 1b The distance between the auxiliary patterns 2a and 2b disposed in the vicinity of each other becomes very close to each other. 6 (b), in addition to the hole patterns 21a and 21b corresponding to the main patterns 1a and 1b, the cross-section of the resist pattern 20 formed on the transferred body A concave portion 22 is formed in the middle portion, which causes a large loss of the resist film thickness. The local decrease in the residual film of the resist may adversely affect the processing stability of the display device substrate by using the resist pattern as an etching mask.

Here, the inventor of the present invention has found that, with respect to the pattern for hole formation of Reference Example 3 in which there is a disadvantage that the resist remnant is locally reduced as described above while having favorable characteristics in Eop or DOF, .

≪ Configuration of photomask >

Next, the structure of a photomask for manufacturing a display device according to an embodiment of the present invention will be described.

In the photomask for manufacturing a display device according to the embodiment of the present invention,

A photomask for manufacturing a display device having a transfer pattern on a transparent substrate,

Wherein the transfer pattern

A main pattern made of a rectangular light transmitting portion,

An auxiliary pattern composed of a phase shift portion disposed in the periphery of the main pattern,

And a low light-transmitting portion formed in a region other than the main pattern and the auxiliary pattern,

Wherein when defining a regular octagonal band of a predetermined width surrounding the main pattern in the vicinity of the main pattern, the auxiliary pattern constitutes at least a part of the regular octagonal band,

Wherein when one of the plurality of main patterns included in the transfer pattern is a first main pattern, a second main pattern different from the first main pattern is disposed at a position approaching the first main pattern,

An auxiliary pattern having a missing portion in one section facing the second main pattern among the eight sections constituting the regular octagonal band surrounding the first main pattern is arranged around the first main pattern.

Hereinafter, this will be described in detail with reference to FIG.

Fig. 7 is a schematic plan view of a transfer pattern of a photomask for manufacturing a display device according to an embodiment of the present invention. Fig. 7 (a) is a schematic plan view and Fig. 7 .

The photomask for manufacturing a display device (hereinafter, simply referred to as a photomask) may be formed by, for example, patterning the phase shift film 11 and the low light transmittance film 12 formed on the transparent substrate 10 And a transfer pattern formed by the transfer pattern. This transfer pattern includes main patterns 1 (1a and 1b) and auxiliary patterns 2 (2a and 2b) arranged in the periphery of main pattern 1. The auxiliary pattern 2 has a shape constituting at least a part thereof when defining a regular octagonal band of a predetermined width surrounding the main pattern 1. [

Two main patterns 1 are arranged in the X direction, one of which is the first main pattern 1a and the other is the second main pattern 1b. The auxiliary pattern 2a is disposed around the first main pattern 1a and the auxiliary pattern 2b is disposed around the second main pattern 1b. In Fig. 7A, the left main pattern is the first main pattern and the right main pattern is the second main pattern. However, either of them may be the first main pattern.

The main pattern 1 is composed of the transparent portion 4 in which the transparent substrate 10 is exposed and the auxiliary pattern 2 is formed in such a manner that the phase shift film 11 on the transparent substrate 10 is exposed And a shift portion 5. The regions other than the main pattern 1 and the auxiliary pattern 2 are formed as the low light transmissive portions 3 on the transparent substrate 10 on which at least the low light transmittance film 12 is formed.

In the present embodiment, the low light-transmissive portion 3 is formed by laminating the phase shift film 11 and the low light-transmissive film 12 on the transparent substrate 10. The phase shift film 11 has a phase shift amount for shifting the exposure light of the representative wavelength in the wavelength range of i line to g line by approximately 180 degrees. The transmittance of the phase shift film 11 with respect to the exposure light of the representative wavelength is T1 (%).

The low light transmittance film 12 may have a predetermined low transmittance with respect to the representative wavelength of the exposure light. In the present embodiment, the low light transmittance film 12 has a transmittance T2 (%) lower than the transmittance T1 (%) of the phase shift film 11 with respect to the exposure light of the representative wavelength in the wavelength range of i- . Alternatively, the low light-transmitting film 12 may be a light-shielding film which does not substantially transmit the exposure light.

Here, in the case of forming a fine pattern (hole pattern) corresponding to the main pattern 1 of the photomask on the photoconductor by exposure using the photomask, if the diameter W1 of the main pattern 1 is 4 μm or less, A fine pattern of a diameter W2 (占 퐉) (W1? W2, more preferably W1> W2) can be formed on the transferred body.

Concretely, the diameter W1 (占 퐉) of the main pattern 1 is preferably 0.8? W1? 4.0, more preferably 1.0? W1? 3.5. Additionally, 1.2 < W1 ≤ 3.0 can be satisfied, and when more fineness is required, 1.2 < W1 < 2.5.

The diameter W2 (占 퐉) of the hole pattern formed on the transferred body as the transfer image of the main pattern 1 is preferably 0.8? W2? 3.0, more preferably 0.8? W2? 2.5, Preferably, 0.8? W2? 2.0 or 0.8? W2? 1.8. Alternatively, 0.8 < W2 < 2.0 or 0.8 < W2 < If more fineness is required, 0.8 < W2 < 1.5.

The photomask according to the present embodiment can be used for the purpose of forming a fine-size pattern useful for manufacturing a display device. For example, when the diameter W1 of the main pattern 1 is 3.0 mu m or less, a more remarkable effect can be obtained.

Incidentally, in the photomask (for example, the above-mentioned Reference Examples 1 to 3) in which a hole pattern is to be formed on the transferred body, it is advantageous to give the mask bias? 1 as described above. In other words, W1 = W2 may be satisfied, where W1 represents the diameter of the hole pattern on the photomask, and W2 represents the diameter of the hole pattern formed on the transferred body. For example, assuming that? 1 (μm) is a bias value W1-W2 and? 1> 0 (μm), the bias value? 1 (μm) is preferably 0.2?? 1? 1.0, , 0.2?? 1? 0.8. By defining the relationship between the diameter W1 and the diameter W2 as the bias value beta 1 in this way, it is possible to obtain a favorable effect of reducing loss of the film thickness of the resist pattern on the transferred body.

The main pattern 1 has a rectangular pattern, and the diameter W1 of the main pattern 1 is a dimension of one side of a quadrangle. For example, if the main pattern 1 is a square pattern, the diameter W1 of the main pattern 1 refers to the dimension of one side, and if the main pattern 1 is a rectangular pattern, the diameter W1 refers to the dimension of the long side . The shape of the main pattern 1 refers to the shape when the main pattern 1 is viewed from the plane. The diameter W2 of the hole pattern formed on the transferred body refers to the length of the largest part of the distance between two opposed sides.

The mask bias? 1 as described above can also be given to the photomask relating to the present embodiment. In the present embodiment, the dimension given by the mask bias? 1 may be larger than the isolated pattern (the above-mentioned Reference Examples 1 to 3) due to the fact that the two hole forming patterns are formed close to the predetermined distance.

In the photomask according to this embodiment, it is preferable that mask bias of unequal dimensions be given to the X direction and the Y direction perpendicular thereto in accordance with the positional relationship of the two hole forming patterns arranged close to each other It happens. Let the bias amounts be? 2 and? 2 (x) and? 2 (y), respectively, for the bias amounts given to the X direction and the Y direction perpendicular thereto. The details of the mask bias? 2 will be described later.

The phase difference? Between the main pattern 1 and the auxiliary pattern 2 is approximately 180 degrees with respect to the representative wavelength of the exposure light used for exposure of the photomask of the present embodiment having the transfer pattern. That is, the phase difference? 1 between the light of the representative wavelength transmitted through the main pattern 1 and the light of the representative wavelength transmitted through the auxiliary pattern 2 is approximately 180 degrees. Approximately 180 degrees, and 120 to 240 degrees. The phase difference? 1 is preferably 150 to 210 degrees.

The photomask of the present embodiment is remarkably effective when exposure light including at least one of i-line, h-line, and g-line is used. Particularly, the photomask of the present embodiment has a broad wavelength It is preferable to apply the light as exposure light. In this case, any wavelength in the wavelength range of i-line to g-line can be a representative wavelength. For example, the photomask of this embodiment can be configured with the h-line as the representative wavelength. More preferably, the phase difference? 1 with respect to the representative wavelength is? 1 = 180 degrees.

In order to realize the phase difference in the photomask of the present embodiment, the main pattern 1 is a transparent portion 4 in which the main surface of the transparent substrate 10 is exposed, the auxiliary pattern 2 is a transparent portion, The phase shifting portion 5 formed by exposing the phase shifting film 11 formed on the semiconductor substrate 10 and the phase shifting amount of the phase shifting film 11 with respect to the representative wavelength may be approximately 180 degrees.

The transmittance T1 of the phase shifting portion 5 can be made as follows. That is, assuming that the transmittance of the phase shift film 11 formed on the phase shifting portion 5 with respect to the representative wavelength is T1 (%), preferably 20? T1? 80, more preferably 30? T1 ? 75, and more preferably 40? T1? 75. When the transmittance of the auxiliary pattern 2 is high, the width d of the auxiliary pattern can be made small in order to obtain a predetermined amount of transmitted light, so that the degree of freedom to arrange There is an advantage to be able to. On the other hand, if the transmittance T1 is slightly lowered and the auxiliary pattern width d is widened, there is an advantage that the difficulty in manufacturing the pattern formation is alleviated. In such a case, the transmittance T1 is preferably 40 to 60 (%). Here, the transmittance T1 (%) is defined as the transmittance of the representative wavelength when the transmittance of the transparent substrate 10 is taken as the reference (100%).

In the photomask of this embodiment, a low light-transmissive portion 3 is formed in a region other than the region where the main pattern 1 and the auxiliary pattern 2 are formed. Here, the main pattern 1 and the auxiliary pattern 2 are separated through the low light-transmissive portion 3. The low light-transmissive portion 3 can be configured as follows.

The low light transmissive portion 3 is a low light transmissive film (i.e., a light shielding film) 12 that does not substantially transmit the exposure light (light of a representative wavelength in the i-line to the g-line wavelength range) (OD > = 3) is formed on the transparent substrate 10.

The low light-transmissive portion 3 may be formed by forming a low light-transmissive film 12 that transmits exposure light in a predetermined range of transmittance. However, when the exposure light is transmitted through the predetermined range of transmittance, the transmittance T3 (%) of the low light-transmissive portion 3 with respect to the representative wavelength is 0 < T3 &lt; T1, and preferably satisfies 0 &lt; T3 &amp;le; 20. In the case where the phase shift portion 5 is not a single layer film of the phase shift film 11 but a multilayer film of the phase shift film 11 and the low light transparency film 12, the transmittance to the laminated film is T3 ( %). Here, the transmittance T3 (%) is also defined as the transmittance of the representative wavelength with reference to the transmittance of the transparent substrate 10 as described above.

In the case where the low light transmitting film 12 transmits the exposure light in the predetermined range of transmittance, the phase shift amount? 3 in the laminated state of the phase shift film 11 and the low light transmittance film 12 is preferably Is 90 (degrees) or less, and more preferably 60 (degrees) or less. Means that the phase difference is "(2n-1/2)? To (2n + 1/2)? (Where n is an integer)" in the case of the radian notation. As for the phase difference, it is assumed that the representative wavelength included in the exposure light is as described above.

The properties of the low light-transmittance film 12 used in the photomask of the present embodiment are not substantially transparent to light of the representative wavelength (OD? 2, more preferably OD> 3) , The transmittance (T2 (%)) of less than 30 (%) (that is, 0 <T2 <30) and the phase shift amount 2 is preferably about 180 degrees. Approximately 180 degrees, and 120 to 240 degrees. Preferably, the phase shift amount? 2 is 150 to 210 degrees.

Here, the transmittance T2 (%) is also taken as the transmittance of the representative wavelength with reference to the transmittance of the transparent substrate 10 as described above.

When the width of the auxiliary pattern 2 is d (占 퐉) in the transfer pattern according to the present embodiment, a remarkable effect can be obtained when the following formula (1) is established.

0.5? (T1 / 100) 占 d? 1.5 (One)

In this case, when the distance between the center of the main pattern 1 and the center of the width direction of the auxiliary pattern 2 is defined as a slit pitch L (μm), preferably 1.0 <L? 5.0, more preferably 1.5 &Lt; L? 4.5. However, the auxiliary pattern 2 constitutes at least a part of the region of the regular octagonal band surrounding the main pattern 1 via the low light-transmissive portion 3. Therefore, the slit 3 is formed between the main pattern 1 and the auxiliary pattern 2, that is, between the auxiliary pattern 2 and the main pattern 1, The pitch L, and the diameter W1 of the main pattern.

The width d (μm) of the auxiliary pattern 2 is set such that the auxiliary pattern having the transmittance T 1 is not resolved in the exposure conditions (the used exposure apparatus) applied to the photomask of the present embodiment. Specifically, for example, the width d (μm) of the auxiliary pattern 2 is preferably d? 0.7, more preferably d? 0.8. In comparison with the width W1 (占 퐉) of the main pattern 1, d? W1 is preferable, and d? W1 is more preferable.

Further, with respect to the width d (μm) of the auxiliary pattern 2, the relational expression shown by the above formula (1) is more preferably the following formula (1) -1, 1) -2.

0.7? (T1 / 100) x d? 1.2 ... (1) -1

0.75? (T1 / 100) x d? (2) -2

The shape of the main pattern 1 included in the transfer pattern in this embodiment is a quadrangle. Specifically, the shape of the main pattern 1 is preferably, for example, a square or a rectangle. When the shape of the main pattern 1 is a quadrangle, the distance between the center position of the quadrangle and the center of the width direction of the auxiliary pattern 2 becomes the slit pitch L. [

In the present embodiment, when defining a regular octagonal band of a predetermined width surrounding the main pattern 1 in the periphery of the main pattern 1, the auxiliary pattern 2 constitutes at least a part of the regular octagonal band Pattern. A regular octagonal band is an octagon with an outer and an inner circumference, and is a shape with a substantially constant width. As shown in Fig. 7, the auxiliary pattern 2 has a constant width except for the corner portions. The regular octagonal band in which the auxiliary pattern 2 is defined is arranged around the main pattern 1 so as to surround it. The center of the regular octagon, which is the inner edge and outer edge of the regular octagonal band of the auxiliary pattern 2, is located at the same position as the center of the main pattern 1. [ In this embodiment, as shown in Fig. 8, the regular octagonal band is divided into eight sections corresponding to the respective sides of the octagonal outer (or inner) circumference. Here, of the eight sections, the section at the right end of Fig. 8 is defined as section A, and the upper section adjacent to this section is defined as section H and the lower section is defined as section B. In other words, the sections B, C, D, E, F, G,

4, in the case where the first main pattern 1a is disposed at a position where the second main pattern 1b approaches, in the present embodiment, in the vicinity of the first main pattern 1a, An auxiliary pattern 2a having a shape with a missing portion is disposed in one of the eight sections A to H constituting the octagonal band and facing the second main pattern 1b side. Specifically, as shown in Fig. 7A, an auxiliary pattern 2a in which a part of an octagonal band is partially missing is arranged around the first auxiliary pattern 1a. As shown in the drawing, the auxiliary pattern 2a adhering to the first main pattern 1a has a defect on the side facing the second main pattern 1b, that is, the partition on the right end (corresponding to the partition A) Shape. The auxiliary pattern 2b attached to the second main pattern 1b also has a shape that has a gap in one section (corresponding to the section E) facing the first main pattern 1a. That is, the main pattern has an auxiliary pattern in the form of an octagonal strip, each of which has a defect in one section on the side where the two main patterns face each other.

That is, when two hole forming patterns are arranged at an approach distance equal to or shorter than a predetermined distance, the auxiliary pattern provided by each main pattern is missing between the two main patterns. Thus, if the centers of the two main patterns are connected by a straight line (not shown), this straight line does not traverse the auxiliary pattern at all.

Further, it is preferable that the auxiliary pattern is not substantially disposed in the region S (indicated by a dotted line in Fig. 7 (a)) sandwiched between mutually facing sides of the two main patterns. However, when a part of the auxiliary pattern enters the area S, it is preferable that the part does not have sides parallel to the mutually facing sides of the two main patterns. In the embodiment shown in Fig. 7, the end portion of the auxiliary pattern is contained in the region S, but the end portion has only sides that are inclined with respect to mutually facing sides of the two main patterns.

It is preferable that the area S does not have an island shape (a shape enclosed by a closed straight line or a curved line) auxiliary pattern.

More preferably, at least 90% of the area in the area S is preferably composed of a low light-transmissive portion. By doing so, the shape of the resist pattern of the two hole patterns formed on the transferred body becomes favorable, and the loss of the resist film thickness can be suppressed.

By disposing the auxiliary patterns 2a and 2b in which some sections are missing in this way, loss of the resist film thickness by the recessed portion 22 shown in FIG. 6 (b) is eliminated as shown in FIG. 9, Thereby forming a resist pattern shape having a profile. 6 (b) and FIG. 9 both show cases in which the hole pitch P is 8 m.

The permissible range of loss of the resist film thickness, which can be seen in FIG. 6 (b), can be determined by the manufacturing conditions of the display device to be obtained by using the photomask. When the initial film thickness (coating film thickness) of the resist film is taken as 100%, the allowable range of the loss is 10% or less of the initial film thickness, more preferably 5% or less.

Therefore, in the present embodiment, whether or not the auxiliary patterns 2a and 2b attached to the main patterns 1a and 1b approaching each other are partially broken can be determined by examining the loss amount of the resist film thickness by experiments or simulations , And judge based on the result. Specifically, when the amount of loss of the resist film thickness is, for example, more than 10%, the auxiliary patterns 2a and 2b are partially broken, and when the loss is 10% or less, the auxiliary patterns 2a and 2b are not lost It is useful to judge.

In the case where the second main pattern 1b is disposed at a position close to the first main pattern 1a and the distance D (see FIG. 4) between the auxiliary patterns 2a and 2b is 1.0 μm or less It is preferable that the auxiliary pattern 2a disposed on the periphery of the first main pattern 1a be divided into sections (the above-mentioned section A) facing the second main pattern 1b side. Likewise, in the second main pattern 1b, it is preferable to form the auxiliary pattern 2b in which the partition facing the first main pattern 1a side (the above-mentioned section E) is missing. It is more preferable that the gap of the partition is applied when the distance D between the auxiliary patterns 2a and 2b becomes 1.5 m or less.

The above is exemplified in consideration of the marine performance of the exposure apparatus for a display device.

The distance between the auxiliary patterns refers to the distance between the opposed compartments (the length of the vertical line) as shown in Fig. As shown in the drawing, the auxiliary patterns 2a and 2b, which are adjacent to each other in the direction in which the two main patterns 1a and 1b are present and correspond to the auxiliary patterns 2a and 2b, respectively, The distance between the sides of the auxiliary patterns 2a and 2b facing each other (facing each other) becomes the distance D between the auxiliary patterns in the arrangement direction of the two main patterns 1a and 1b.

In the photomask of the present embodiment, when the hole pitch P, which is the center-to-center distance of the main patterns 1a and 1b, is 1.6 mu m or more, preferably 3 mu m or more, the remarkable effect of the present invention can be obtained. If the value of the hole pitch P is too small, the residual amount of the resist pattern formed at the corresponding position between the main patterns may not be sufficiently obtained, or the numerical value of the mask bias? 2 described later becomes too large, There is a risk of inconveniences such as

Hereinafter, an optical simulation according to an embodiment of the present invention and a reference example will be described.

10 (a), 10 (b) and 10 (c) are schematic plan views showing the main parts of the transfer pattern provided in the photomask of the reference example. Example 7 (e) shows Reference Example 8. FIG. 11 is a plan schematic diagram showing a main part of a transfer pattern provided in a photomask according to an embodiment of the present invention, wherein (f) shows Embodiment 1, (g) shows Embodiment 2, ) Shows the fourth embodiment.

10 (a) shows a case where the hole pitch P (see Figs. 5 to 7) of the main patterns 1a and 1b is 16 占 퐉 and the auxiliary patterns 2a and 2b of the regular octagonal band have no missing portions 10B shows a case where the hole pitch P of the main patterns 1a and 1b is 12 μm and the auxiliary patterns 2a and 2b do not have any missing partitions. 10C shows a case where the hole pitch P of the main patterns 1a and 1b is 9 mu m and the auxiliary patterns 2a and 2b do not have any division. Fig. 10 (d) The hole pitch P of the auxiliary patterns 1a and 1b is 8.75 mu m and the auxiliary patterns 2a and 2b do not have any missing portions. 10E shows a case where the hole pitches P of the two main patterns 1a and 1b are 8.75 mu m and one section of each of the auxiliary patterns 2a and 2b is combined and shared.

11 (f) shows a case in which the hole pitch P of the main patterns 1a and 1b is 8.75 m and the auxiliary patterns 2a and 2b are separated into one compartments. Fig. 11 (g) And the hole pitch P of the auxiliary patterns 1a and 1b is 8 占 퐉 and the auxiliary patterns 2a and 2b are one-compartments. 11 (h) shows a case in which the hole pitch P of the main patterns 1a and 1b is 7.5 占 퐉 and the auxiliary patterns 2a and 2b are separated by one compartment. Fig. 11 (i) The hole pitch P of the auxiliary patterns 1a and 1b is 7 占 퐉 and the auxiliary patterns 2a and 2b are separated into three compartments.

In this simulation, the case of using the photomask (binary mask) shown in Fig. 2 (a) is referred to as Reference Example 1, and the photomask (halftone phase shift mask) shown in Fig. Was used as Reference Example 2. &lt; tb &gt; &lt; TABLE &gt; The main patterns applied to the reference example 1 and the reference example 2 are all the isolated patterns without the auxiliary pattern.

As a result of performing optical simulation on the patterns of the respective photomasks, the results shown in Fig. 12 were obtained. In this simulation, with reference to Dose (Eop Dose) of 80 mJ / cm 2, which is the exposure energy used for transferring the main pattern (isolated pattern) shown in FIG. 2C, except for Reference Example 1 and Reference Example 2 . When this Dose was applied, the resist pattern formed on the transferred body was evaluated. Further, "panel X-CD" and "panel Y-CD" are dimensions in the X direction and the Y direction of the hole pattern formed on the transferred body corresponding to the main pattern of the photomask. In each of the reference examples and the embodiments, the target dimensions of X-CD and Y-CD are set to 1.5 탆.

10A, since the two main patterns 1a and 1b are sufficiently separated from each other, each of the main patterns 1a and 1b substantially exhibits optical performance as an isolated pattern do. This also applies to the reference example 5 of FIG. 10 (b) and the reference example 6 of FIG. 10 (c). On the other hand, when the two main patterns 1a and 1b approach and the hole pitch P narrows to 8.75 mu m as in the reference example 7 of FIG. 10D, the distance D between the auxiliary patterns 2a and 2b becomes Lt; / RTI &gt; At this time, the resist film thickness loss exceeds 12%.

Here, even when the auxiliary patterns 2a and 2b of the main patterns 1a and 1b approaching each other are partially combined and shared as one (one section) as in the reference example 8 of FIG. 10 (e) , The loss of resist film thickness is close to 12% and is not much improved.

This problem is considered to be related to the photoresist applied to the manufacture of a display device according to the study of the present inventors. Specifically, the resist (positive photoresist) used in the manufacture of display devices is designed to have high sensitivity, unlike those for semiconductor device manufacturing. Therefore, a corresponding film is inevitable even at a relatively low dose amount, and a local film thickness loss is likely to occur at an unintended portion.

The interaction between the main pattern 1 and the auxiliary pattern 2 generated in the photomask of Reference Example 3 is such that the optical image formed by the light of the inverted phase transmitted through the auxiliary pattern 2 is transmitted through the main pattern 1 A phenomenon of increasing the intensity peak of light by light is used. Then, excellent transfer performance (DOF, MEEF) as shown in Fig. 3 was obtained. On the other hand, the intensity of the light transmitted through the auxiliary pattern slightly increases due to the interaction with the main pattern 1. Since the photoresist used for manufacturing the display device has a high sensitivity and the auxiliary patterns 2 are in proximity to each other and the auxiliary patterns 2 are shared by the plurality of main patterns 1, It is considered that there is a risk that the thickness of the resist on the transferred body is reduced.

On the other hand, in the embodiment 1 of Fig. 11 (f), one section of the eight sections constituting the regular octagonal band surrounding the first main pattern 1a is faced to the side of the second main pattern 1b And the auxiliary pattern 2a having the remaining seven sections is arranged around the first main pattern 1a. That is, of the regular octagonal bands surrounding the periphery of the first main pattern 1a, the auxiliary pattern which is closest to the regular octagonal band surrounding the periphery of the second main pattern 1b, (2a). Likewise, for the second main pattern 1b, one section faced to the first main pattern 1a is omitted, and the remaining auxiliary pattern 2b having the seventh section is separated from the periphery of the second main pattern 1b .

When the auxiliary pattern section is to be broken, it is not always necessary to cut it along the boundary line of the section shown in Fig. 8, and at least the main section of the section is to be broken as shown in Fig. 7 (a) . It is preferable that the area of the missing portion is 80% or more of the area of the number of the divided portions, which is the same as, for example, 80% or more of the area of one of the eight divided portions. At this time, a portion where only the low light-transmissive portion 3 is present is formed between the two main patterns, and a straight line connecting the centers of the main patterns 1a and 1b does not traverse the auxiliary pattern.

In this way, in the auxiliary pattern of the approaching main pattern, when the mutually facing sections are missing, the loss of the resist film thickness in the formed resist pattern becomes zero, and the loss is greatly reduced, and a remarkable effect can be obtained Able to know. Such an effect can be obtained when the main patterns 1a and 1b are further brought closer to each other (hole pitch P = 1), as in the case of the embodiment 2 of FIG. 11G or the embodiment 3 of FIG. 11H, 8 占 퐉 and P = 7.5 占 퐉). The cross-sectional structure of the resist pattern in this case is the same as that shown in Fig.

11 (f) to (i), although the exposure doses as in the reference examples 4 to 8 are applied, the diameter of the hole pattern transferred to the resist film is slightly smaller than the original target dimension It is small. Specifically, regarding the first embodiment, the X-CD (the diameter in the X direction) is 1.39 (μm) and the Y-CD (the diameter in the Y direction) is 1.37 mu m). Therefore, in order to bring the X-CD and Y-CD on the transfer target close to the target dimension (1.5 mu m), it is required to make the mask bias? 1 larger than 0.5 mu m to form a hole pattern.

In order to make the X-CD and the Y-CD on the transfer target body have the same target dimension (1.5 mu m), it is preferable to provide appropriate mask bias? 2 in the X direction and the Y direction, respectively.

Here, as shown in Fig. 12, in the embodiments of Figs. 11F to 11H, by giving appropriate mask biases? 2 (x) and? 2 (y) to the CD on the mask, , X-CD, and Y-CD together have a target dimension of 1.5 占 퐉.

As a result, in the case of the photomask of the embodiment shown in Figs. 11 (f) to 11 (h), the numerical value 24 of DOF (depth of focus) , It is understood that the hole pattern having a larger diameter than the halftone phase shift mask (refer to FIG. 2 (b)) of Reference Example 2 can be stably formed on the transferred body. Further, since the Eop Dose necessary for exposure is smaller than that of the binary mask of Reference Example 1 or the halftone phase shift mask of Reference Example 2, the exposure process can be efficiently performed.

11 (f) to 11 (h), the auxiliary pattern 2a adjoining the first main pattern 1a and the auxiliary pattern 2b accompanying the second main pattern 1b ), One of the eight compartments facing each other is omitted. That is, for one main pattern 1, the number of divisions of the auxiliary pattern 2 is seven. On the other hand, when the two main patterns 1a and 1b are disposed closer to each other, it is also possible to further shorten the division located on both sides with the division already lost. For example, in the embodiment 4 shown in Fig. 11 (i), among the eight sections of the auxiliary pattern 2a adjoining the first main pattern 1a, the section A and the sections B and H located on both sides thereof And the partition E and the sections D and F located on both sides of the auxiliary pattern 2b corresponding to the auxiliary pattern 2b attached to the second main pattern 1b are lost so that the loss of the resist film thickness Zero. As a result, in this embodiment, for one main pattern 1, the number of divisions of the auxiliary pattern 2 is set to 5 by eliminating three divisions. In addition, the number of main patterns disposed closer to each other is not limited to 2, and a larger number of hole forming patterns can be disposed at a distance approaching the center.

When the number of main patterns included is N and the total number of sub-patterns of the auxiliary patterns is K in a pattern group including a plurality of main patterns (each approaching at least one other) arranged close to each other,

K? (8-1) N

.

11 (f) to 11 (i), only the case where the second main pattern 1b approaches the X-direction (left-right direction in the drawing) with respect to the first main pattern 1a is exemplified, It is possible to arrange the auxiliary pattern 2 in which any one of the eight sections is missing as described above.

The present invention can also be effectively applied to the case where the second main pattern 1b approaches the first main pattern 1a in a diagonal direction of the main pattern 1, for example, when the second main pattern 1b approaches obliquely. Even in this case, at least one of the eight sections of the auxiliary pattern 2a adjoining the first main pattern 1a may be broken off at least one section facing the second main pattern 1b.

Even in the case where the third main pattern and the fourth main pattern are disposed closer to the first main pattern, the sub-patterns on the side facing each other out of the eight sub-patterns of the auxiliary patterns, Can be dropped. In this case, by the relative arrangement of the plurality of main patterns, in addition to the main pattern having the auxiliary pattern of seven compartments, the main pattern having the auxiliary pattern of the five compartments, the six compartments, the four compartments, the three compartments, the two compartments, A main pattern having an auxiliary pattern may be present.

For example, the two main patterns may be a pattern group having an auxiliary pattern missing one compartment by one, or a pattern group having auxiliary patterns missing three compartments each.

Alternatively, the three main patterns may be grouped into patterns each having one or two sub-divided auxiliary patterns by the arrangement (X direction, Y direction, or X and Y directions, and so on). In addition, the four main patterns may be grouped into a pattern group having an auxiliary pattern which is divided into 1 to 5 sections by the arrangement.

Hereinafter, five, six, or seven main patterns are respectively referred to as an auxiliary pattern group in which one to six sections are missing by the arrangement, or eight main patterns are arranged in the order of one to seven divisions It may be a pattern group having auxiliary patterns.

On the other hand, the auxiliary pattern of one main pattern can be free from any missing part other than the area on the side facing the other main pattern, or the area on both sides.

In addition, depending on the approach direction of the plurality of hole forming patterns, the diameter of the hole pattern formed on the transferred body may be different in the X direction and the Y direction. This is because the variation of the optical image caused by the loss of some sections of the auxiliary pattern occurs unevenly in the X and Y directions. Here, in order to compensate the influence on the uneven optical image in the X direction and the Y direction, it is useful to give the mask bias? 2 of different dimensions in the X direction and the Y direction to the pattern drawing data.

For example, as shown in FIG. 7A, the first main pattern 1a and the second main pattern 1b are arranged in the X direction and the auxiliary patterns attached to the main patterns 1a and 1b The mask bias? 2 (?) Given to the dimensions of the first main pattern 1a and the second main pattern 1b (i.e., the width of the first main pattern 1a and the second main pattern 1b) (y)>? 2 (x), where? 2 (x) is the applied amount in the X direction and? 2 (y) is the applied amount in the Y direction.

Concretely, a positive bias? 2 (positive direction in the direction perpendicular to the direction in which the missing portion of the auxiliary pattern exists (the X direction in FIG. 7A) (the Y direction in FIG. 7A) (y). Further, if necessary, negative bias? 2 (x) can be given in the direction in which the missing portion of the auxiliary pattern exists (X direction in FIG. 7A).

The transfer pattern of the photomask including the main patterns 1a and 1b imparted with the mask bias? 2 is exemplified in Fig. As a result of adding the mask bias? 2, the dimension of the main patterns 1a and 1b in the X direction is smaller than the dimension in the Y direction, and the shape of the main patterns 1a and 1b is a vertically elongated rectangular shape Respectively.

11 (g), the hole pattern formed on the transferred body is a long rectangular shape (X-CD = 1.40 mu m, Y-CD = 1.37 mu m). Therefore, if the shape of the main patterns 1a and 1b is formed into a vertically elongated rectangular shape by the application of the mask bias, the error of the pattern dimensions due to the partial division of the auxiliary patterns 2a and 2b can be eliminated have. As a result, it is possible to form a hole pattern having the same dimension in the X direction and the dimension in the Y direction on the transferred body.

Therefore, by the optical simulation, it is possible to obtain the bias amount? 2 for each of the X direction and the Y direction so that the dimensions in the X direction and the Y direction become equal on the transferred body, and reflect it on the pattern drawing data.

Therefore, in the transfer pattern of the photomask, the main pattern imparted with the bias? 2 becomes a rectangular shape. That is, the first main pattern is a rectangle having a long side on the side facing the second main pattern at the approaching position.

13, the long side W3 (y) of the main pattern becomes W3 (y) = W1 +? 2 (y) and the short side W3 (x) becomes W3 (x) = W1 +? 2 (x). Then, W3 (x) and W3 (y) preferably satisfy the following equations.

As for the long side,

W3 (y)? 4.0, more preferably 1.0? W3 (y) &lt; 3.5

As for short sides,

W3 (x)? 4.0, more preferably 1.0? W3 (x)? 3.0

As described above, when the photomask of the present embodiment is used as a photomask for manufacturing a display device, that is, when the photomask of the present embodiment is used in combination with a photoresist for manufacturing a display device, The loss of the resist film thickness at the corresponding portion can be greatly reduced.

&Lt; Method of manufacturing photomask &gt;

Next, an example of a method of manufacturing a photomask applicable to the embodiment of the present invention will be described below with reference to Figs. 14 (a) to 14 (f). 14 (a) to 14 (f) show only a sectional view on the left side and a top view on the right side, and for the sake of simplicity, only the first main pattern and auxiliary patterns accompanying it are shown in the photomask pattern shape.

First, as shown in Fig. 14A, a photomask blank 30 is prepared. In this photomask blank 30, a phase shift film 11 and a low light-transmittance film 12 are formed in this order on a transparent substrate 10 made of glass or the like. In the first photoresist film 13, Respectively.

The phase shift film 11 is formed on the main surface of the transparent substrate 10. The phase shift film 11 preferably has a transmittance T1 (%) with respect to its representative wavelength of preferably 20 to 80 (%) when the i-line, h-line or g- , Preferably 30 to 75 (%), and more preferably 40 to 75 (%). Further, the phase shift amount of the phase shift film 11 with respect to the representative wavelength is approximately 180 degrees. With this phase shift film 11, the phase difference of the transmitted light between the main pattern made of the light transmitting portion and the auxiliary pattern made up of the phase shifting portion can be made about 180 degrees. This phase shift film 11 shifts the phase of the light of the representative wavelength in the wavelength range of i line to g line by approximately 180 degrees. As a method of forming the phase shift film 11, a known method such as a sputtering method can be applied.

It is preferable that the phase shift film 11 is formed of a material that satisfies the transmittance and the retardation and is wet etched as described below. However, if the amount of the side etching generated during the wet etching becomes too large, defects such as deterioration of the CD accuracy and destruction of the upper layer film due to undercut occur. Therefore, the film thickness of the phase shift film 11 is preferably 2000 angstroms or less, preferably 300 to 2000 angstroms, and more preferably 300 to 1800 angstroms.

In order to satisfy these conditions, the material of the phase shift film 11 preferably has a refractive index of a representative wavelength (for example, h line) included in the exposure light of preferably 1.5 to 2.9, more preferably 1.8 To 2.4.

In order to sufficiently exhibit the phase shift effect, it is preferable that the pattern end face (etched surface) by the wet etching is nearly perpendicular to the main surface of the transparent substrate 10.

Considering the above properties, the material of the phase shift film 11 is preferably a material containing any one of Zr, Nb, Hf, Ta, Mo, and Ti and Si or an oxide, a nitride, an oxynitride, A material containing oxynitride carbide can be used.

A low light-transmittance film 12 is formed on the phase shift film 11. As the film forming method of the low light-transmissive film 12, known means such as a sputtering method can be applied as in the case of the phase shift film 11. It is preferable that the phase shift film 11 has a wavelength dependency of the phase shift amount within 40 degrees of fluctuation width with respect to i-line, h-line, and g-line.

The low light-transmissive film 12 can be composed of a light-shielding film that does not substantially transmit the exposure light. In addition, the low light-transmittance film 12 may be formed of a film having a predetermined low transmittance with respect to the representative wavelength of the exposure light. The low light transmittance film 12 used in the production of the photomask of the present embodiment has transmittance T2 ((%)) lower than the transmittance T1 (%) of the phase shift film 11 with respect to the light of the representative wavelength in the wavelength range of i- %).

In the case where the low light transmittance film 12 transmits the exposure light at a low transmittance, the transmittance and the phase shift amount of the low light transmittance film 12 with respect to the exposure light are the transmittance and the phase shift amount of the low light transmittance portion of the photomask of the present embodiment Can be achieved. Preferably, in the laminated state of the phase shift film 11 and the low light transmittance film 12, the transmittance T3 (%) with respect to the light of the representative wavelength of the exposure light is T3? 20, and the phase shift amount? Is not more than 90 (degrees), more preferably not more than 60 (degrees).

As the sole property of the low light-transmitting film 12, it is preferable that the light of the representative wavelength does not substantially transmit, or that the transmittance (T2 (%)) of less than 30 (% , And the phase shift amount 2 is approximately 180 degrees. Approximately 180 degrees, and 120 to 240 degrees. Preferably, the phase shift amount? 2 is 150 to 210 degrees.

The material of the low light-transmissive film 12 may be Cr or a compound thereof (oxide, nitride, carbide, oxynitride or oxynitride carbide), or a silicide of a metal containing Mo, W, Ta, Ti, The compound is also good. However, the material of the low light transmittance film 12 is preferably a material which can be wet-etched like the phase shift film 11 and has an etching selectivity to the material of the phase shift film 11. [ That is, it is preferable that the low light transmitting film 12 has resistance to the etching agent of the phase shift film 11 and the phase shift film 11 has resistance to the etching agent of the low light transmitting film 12.

A first photoresist film 13 is applied on the low light-transmissive film 12. Since the photomask of the present embodiment is preferably drawn by a laser beam drawing apparatus, a photoresist suitable therefor is used. The photoresist constituting the first photoresist film 13 may be either positive or negative, but the following description is made as a positive photoresist.

Next, as shown in Fig. 14 (b), the first photoresist film 13 is drawn by the drawing data based on the transfer pattern using the drawing apparatus (first drawing). Then, the low light transmittance film pattern 12p is formed by wet etching the low light transmittance film 12 using the first resist pattern 13p obtained by the development as a mask. In this step, an area for the low light-transmitting portion is defined and an area for the auxiliary pattern (low light-transmitting film pattern 12p) surrounded by the low light-transmitting portion is defined. A wet etchant (wet etchant) for wet etching may be any known one suitable for the composition of the low light transmittance film 12 to be used. For example, if the low light transmitting film 12 is a film containing Cr, ceric ammonium nitrate or the like can be used as a wet etchant.

Next, as shown in Fig. 14C, the first resist pattern 13p is peeled off. As a result, the low light transmission film pattern 12p and a part of the phase shift film 11 are exposed.

Next, as shown in Fig. 14D, the second photoresist film 14 is applied to the entire surface including the low light-transmitting film pattern 12p.

Next, as shown in FIG. 14E, the second photoresist film 14 is subjected to the second drawing, and then the second resist pattern 14p is formed by the development. Next, the phase shift film 11 is wet-etched using the second resist pattern 14p and the low-transmittance film pattern 12p as a mask. By this etching (development), the main surface of the transparent substrate 10 is exposed to the transparent portion, thereby defining the region of the main pattern made of the transparent portion.

The second resist pattern 14p covers the area to be the auxiliary pattern and has an opening in the area of the main pattern made of the light transmitting part. In this case, it is preferable to sizing the drawing data of the second drawing so that the edge portion of the low light-transmitting film pattern 12p is exposed from the inside edge of the opening of the second resist pattern 14p. By doing so, it is possible to absorb the alignment deviation caused between the first drawing and the second drawing and to prevent deterioration of the CD accuracy of the transfer pattern.

That is, when the second resist pattern 14p is subjected to the sizing at the time of the second drawing, if it is desired to form an isolated hole pattern on the transferred body, the patterning of the phase shift film 11 and the low light- The positional deviation does not occur. Therefore, in the transfer pattern illustrated in Fig. 1, the centers of the main pattern 1 and the auxiliary pattern 2 can be precisely matched.

The wet etchant used for etching the phase shift film 11 is appropriately selected in accordance with the composition of the phase shift film 11.

Next, as shown in Fig. 14 (f), the second resist pattern 14p is peeled off. Thereby, the photomask having the transfer pattern is completed. Fig. 14 shows a case of forming a regular octagonal auxiliary pattern with no division of the divisions. However, when any of the eight divisions is missing, when defining the area of the auxiliary pattern in Fig. 14 (b) The rendering data may be changed according to the position and size of the partition.

In the fabrication of the photomask, dry etching or wet etching is applicable for patterning an optical film such as the phase shift film 11 and the low light transmittance film 12. Any of these may be employed, but wet etching is particularly advantageous in the present invention. This is because the size of the photomask for manufacturing a display device is relatively large, and furthermore, various kinds of sizes exist. When such a photomask is manufactured by applying dry etching that requires a vacuum chamber, the size of the dry etching apparatus and the efficiency of the manufacturing process are lowered.

However, there is also a problem in applying wet etching when manufacturing such a photomask. Since the wet etching has the property of isotropic etching, when the predetermined film is etched and etched in the depth direction, the etching proceeds also in the direction perpendicular to the depth direction. For example, when the slit is formed by etching the phase shift film 11 having the film thickness F (nm), the opening of the resist pattern to be the etching mask is 2 F (nm) (i.e., ), But it is difficult to maintain the dimensional accuracy of the opening of the resist pattern as the slit becomes a fine width. For this reason, it is useful that the width d of the auxiliary pattern is 1 μm or more, preferably 1.3 μm or more.

In addition, when the film thickness F (nm) is large, the amount of side etching becomes large. Therefore, it is advantageous to use a film material having a phase shift amount of about 180 degrees even if the film thickness is small. Therefore, the refractive index of the phase shift film 11 is required to be high with respect to the representative wavelength of the exposure light. Specifically, it is preferable to form the phase shift film 11 using a material having a refractive index with respect to the representative wavelength of preferably 1.5 to 2.9, more preferably 1.8 to 2.4.

The present invention includes a manufacturing method of a display device including a step of transferring the transfer pattern onto a transfer object using a photomask of the present embodiment, exposing the transfer material by an exposure device.

In the method of manufacturing the display device of the present invention, first, the photomask of this embodiment is prepared. Next, the transfer pattern was exposed using an exposure apparatus having an exposure light source including i-line, h-line and g-line with a numerical aperture (NA) of 0.08 to 0.15, To 3.0 (mu m). It is general and advantageous to apply the equal magnification exposure to the exposure.

When transferring a transfer pattern using the photomask of this embodiment mode, a reduction exposure may be used. However, as an exposure apparatus used in a photomask for manufacturing a display device, the following method is preferably employed as a method of performing projection exposure with the same magnification.

For example, the numerical aperture (NA) of the optical system is preferably 0.08? NA <0.20, more preferably 0.08? NA? 0.15, further preferably 0.08 <NA <0.15. Further, the coherence factor? Is 0.4??? 0.9, more preferably 0.4?? 0.7, and still more preferably 0.4 <? 0.6.

The exposure light source uses a light source that includes at least one of i-line, h-line, and g-line in exposure light. In the case of applying exposure light of a single wavelength, i-line is preferably used. On the other hand, it is useful to use a light source (also referred to as a broad wavelength light source) including all of i-line, h-line, and g-line in that sufficient light quantity is secured.

The light source of the exposure apparatus to be used may be an oblique light (annular light) or the like. However, the present invention can sufficiently obtain an excellent effect by using normal illumination without applying the light illumination.

In the method for manufacturing a display device using a mask for manufacturing a display device according to the present invention, transfer can be stably performed on a transferred body even in a fine dense pattern. Concretely, it is possible to form a hole pattern precisely while ensuring the process margin of the process at the time of production such as DOF or MEEF. Further, in forming the dense pattern, the thickness of the resist pattern formed on the transferred body can be sufficiently secured. This increases the CD accuracy in display production, and provides industrial benefits such as stable production and high yield.

1 (1a, 1b) ... Main pattern
2 (2a, 2b) ... Auxiliary pattern
3 ... Low light
4… Transparent portion
5 ... The phase-
10 ... Transparent substrate
11 ... Phase shift film
12 ... Low light-

Claims (7)

A photomask for manufacturing a display device having a transfer pattern on a transparent substrate,
Wherein the transfer pattern
A main pattern made of a rectangular light transmitting portion,
An auxiliary pattern formed of a phase shifting portion disposed in the periphery of the main pattern,
And a low light-transmitting portion formed in a region other than the main pattern and the auxiliary pattern,
Wherein when defining a regular octagonal band of a predetermined width surrounding the main pattern in the vicinity of the main pattern, the auxiliary pattern constitutes at least a part of the regular octagonal band,
Wherein when one of the plurality of main patterns included in the transfer pattern is a first main pattern, a second main pattern different from the first main pattern is disposed at a position approaching the first main pattern,
An auxiliary pattern having a missing portion in one compartment facing the second main pattern out of eight compartments constituting the regular octagonal band surrounding the first main pattern is disposed in the periphery of the first main pattern A photomask for manufacturing a display device. The method according to claim 1,
Wherein the transfer pattern forms a hole pattern having a diameter W2 (W1? W2) as a transfer image of the main pattern on the transfer object when the diameter of the main pattern is W1. Photomask for manufacturing. The method according to claim 1,
And the dimension of the first main pattern in the X direction is smaller than the dimension in the Y direction perpendicular to the X direction when the arrangement direction of the first main pattern and the second main pattern is the X direction. Photomask for manufacturing. The method according to any one of claims 1 to 3,
Wherein the transfer pattern includes a densestion pattern in which at least three of the main patterns are regularly arranged in the X direction, the Y direction perpendicular to the X direction, or the X direction and the Y direction, Wherein each of the patterns has the auxiliary pattern missing at least one of the eight sections facing the other main pattern side. The method according to claim 1,
Wherein the phase shifting portion has a phase shift film for shifting the phase of the exposure light by approximately 180 degrees with a transmittance of 20 to 80% with respect to a representative wavelength of the exposure light on the transparent substrate. . The method according to claim 1,
Wherein the low light transmitting portion is a light shielding portion having an optical density OD with respect to the exposure light of 2 or more. A step of preparing the photomask according to any one of claims 1 to 6;
The transfer pattern is exposed using an exposure apparatus having an exposure number NA of 0.08 to 0.15 and an exposure light source including at least one of i-line, h-line, and g-line, And forming a hole pattern having W2 of 0.8 to 3.0 (mu m).

Images