TWI635353B - Photomask and method of manufacturing a display device - Google Patents

Abstract

An object of the present invention is to obtain an excellent photomask which is suitable for an exposure environment of a photomask for display device manufacturing, and which can stably transfer a fine pattern, and a method of manufacturing the same. The photomask of the present invention includes a transfer pattern formed on a transparent substrate, and the transfer pattern has a main pattern having a diameter of W1 (μm), is disposed in the vicinity of the main pattern, and has a width d (μm). The auxiliary pattern and the low light transmitting portion disposed in a region other than the main pattern and the auxiliary pattern, the phase difference between the representative wavelengths of the main pattern and the auxiliary pattern is substantially 180 degrees, and the diameter W1 and the width d are The transmittance T1 (%) of the auxiliary pattern, the transmittance T3 (%) of the low light transmitting portion, and the distance P (μm) between the center of the main pattern and the center of the auxiliary pattern in the width direction have a specific relationship.

Description

Photomask and display device manufacturing method

The present invention relates to a photomask which is advantageously used for the manufacture of a display device typified by liquid crystal or organic EL (electroluminescence), and a method of manufacturing a display device using the same.

In Patent Document 1, as a photomask for manufacturing a semiconductor device, there is described a phase shift mask in which four auxiliary light transmitting portions are arranged in parallel with each side of a main light transmitting portion (hole pattern), and a main portion is provided The phase of the light of the light transmitting portion and the auxiliary light transmitting portion is reversed.

Patent Document 2 describes a large phase shift mask having a transparent substrate and a translucent phase shift film formed on the transparent substrate.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. Hei 3-15845

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2013-148892

Currently, display devices including liquid crystal display devices or EL display devices are expected Brighter and more power efficient, and improved display performance such as high definition, high speed display, wide viewing angle.

For example, in a thin film transistor ("TFT") used in the above display device, in a plurality of patterns constituting the TFT, the contact holes formed in the interlayer insulating film do not have the upper layer and the lower layer reliably The effect of the pattern connection does not guarantee the correct action. On the other hand, in order to increase the aperture ratio of the display device as much as possible, a bright and power-saving display device is required, and the diameter of the contact hole is required to be sufficiently small. Accordingly, it is desirable that the diameter of the hole pattern provided in the photomask for forming such a contact hole is also fine (for example, less than 3 μm). For example, a hole pattern having a diameter of 2.5 μm or less and a diameter of 2.0 μm or less is required, and in the near future, it is considered to be desirable to form a pattern having a diameter of 1.5 μm or less of less than 2.0 μm. According to this background, a manufacturing technique of a display device capable of reliably transferring minute contact holes is required.

In addition, in the field of a photomask for manufacturing a semiconductor device (LSI (Large Scale Integration)), which has a higher degree of integration than a display device and a remarkably improved pattern, in order to obtain higher The resolution is applied to an optical system using a high NA (Numerical Aperture) (for example, 0.2 or more) in an exposure apparatus, and a process of promoting short-wavelength of exposure light, and using a KrF or ArF excimer laser ( They are a single wavelength of 248 nm and 193 nm, respectively.

On the other hand, in the field of lithography for manufacturing display devices, in order to improve the resolution, the above method is generally not applied. On the contrary, there is a tendency that the NA of the known exposure apparatus such as an LCD (liquid crystal display) is about 0.08 to 0.10, and the exposure light source also includes a wide wavelength region of i light, h light, and g light. Compared with the resolution or the depth of focus, it pays more attention to production efficiency and cost.

However, as described above, in the manufacture of a display device, the miniaturization of the pattern has never been higher. Therefore, if the technology for manufacturing a semiconductor device is directly applied to a display device system There are several problems with making. For example, when converting to an exposure apparatus having a high resolution of high NA (numerical aperture), a large investment is required, and the matching with the price of the display device cannot be obtained. Or, regarding the change of the exposure wavelength (using a short wavelength such as an ArF excimer laser as a single wavelength), it is difficult to apply the display device having a large area itself, and if it is applied, the production efficiency is lowered, and still requires considerable Dazhi Investment is not suitable in the above aspects.

Further, as described below, the photomask for a display device has various problems that are different from those of the photomask for manufacturing a semiconductor device.

According to the above, it is actually difficult to directly convert the photomask of Patent Document 1 into the manufacture of a display device. Further, it is described that the halftone type phase shift mask described in Patent Document 2 has a light intensity distribution higher than that of the binary mask, but there is room for further improvement in performance.

Therefore, in the method of manufacturing a display device using a photomask for manufacturing a display device, it is desirable to achieve the above-described problem, realize a fine pattern, and stably perform transfer onto a transfer target. Accordingly, an object of the present invention is to provide an excellent photomask which is advantageously suitable for an exposure environment of a photomask for display device manufacturing, and which can stably transfer a fine pattern, and a method of manufacturing the same.

In order to solve the above problems, the present invention has the following configuration. The photomask of the present invention is characterized by the following constitutions 1 to 14, and the method of manufacturing the display device of the present invention is characterized by the following configuration 15.

(Composition 1)

The configuration 1 of the present invention is characterized in that the photoreceptor includes a transfer pattern formed on a transparent substrate, and the transfer pattern has a main pattern having a diameter of W1 (μm) and is disposed on the main pattern. An auxiliary pattern having a width of d (μm) in the vicinity of the pattern, and a low light transmitting portion disposed in a region other than the main pattern and the auxiliary pattern, and being transmitted through the main pattern The phase difference between the representative wavelength of the wavelength range of the line ~g light and the representative wavelength of the auxiliary pattern is substantially 180 degrees, and the transmittance of the light passing through the representative wavelength of the auxiliary pattern is set to T1 (%). When the transmittance of the light passing through the representative wavelength of the low light transmitting portion is T3 (%), and the distance between the center of the main pattern and the center of the auxiliary pattern in the width direction is P (μm), the following is satisfied. (1)~(4): 0.8≦W1≦4.0‧‧‧‧‧‧‧‧‧‧‧‧‧ (1)

1.0<P≦5.0‧‧‧‧‧‧‧‧‧‧‧‧‧‧ (3)

T3<T1‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧ (4)

(constituent 2)

According to a second aspect of the invention, in the photomask of the first aspect, the auxiliary pattern is formed by forming a semi-transmissive film having a transmittance of light of the representative wavelength of T1 (%) on the transparent substrate.

(constitution 3)

According to a third aspect of the present invention, in the photomask of the second embodiment, the transmittance T1 (%) of the semi-transmissive film satisfies the following formula (5): 30 ≦ T1 ≦ 80‧ ‧ (5).

(construction 4)

The configuration 4 of the present invention is the photomask according to the second or third aspect, wherein the width d of the auxiliary pattern is 1 (μm) or more.

(Constituent 5)

The photomask according to any one of claims 2 to 4, wherein the main pattern is formed by exposing one of main surfaces of the transparent substrate, and the auxiliary pattern is Forming the semi-transmissive film on the transparent substrate, wherein the low light-transmissive portion is formed on the transparent substrate in sequence or in reverse order, and the transmittance of the semi-transmissive film and the light of the representative wavelength is T2 (%) It is made of low light transmission film.

(constituent 6)

The photomask according to any one of claims 2 to 4, wherein the main pattern is formed by forming an etched portion on a main surface of the transparent substrate, and the auxiliary pattern is on the transparent substrate Forming the semi-transmissive film, wherein the low light transmissive portion is formed on the transparent substrate in sequence or in reverse order, and the transmittance of the semi-transmissive film and the light of the representative wavelength is low (T) (%) Made of light film.

(constituent 7)

The photomask according to any one of 2 to 6, wherein the semi-transmissive film contains a material containing at least one of Zr, Nb, Hf, Ta, Mo, and Ti, and Si, Or materials containing oxides, nitrides, oxynitrides, carbides, or oxynitrides of such materials.

(Composition 8)

The configuration 8 of the present invention is the photomask according to the first aspect, wherein the auxiliary pattern is formed by exposing the transparent substrate.

(constituent 9)

The ninth aspect of the invention is the photomask of the eighth aspect, wherein the main pattern is formed by forming an etched portion on a main surface of the transparent substrate, and the auxiliary pattern is formed by exposing one of main surfaces of the transparent substrate The low light transmitting portion is formed on the transparent substrate to form a low light transmissive film having a transmittance of light of the representative wavelength of T3 (%).

(construction 10)

According to a tenth aspect of the present invention, in the photomask of the eighth aspect, the main pattern is formed by exposing one of main surfaces of the transparent substrate, and the auxiliary pattern is formed by forming an etching portion on a main surface of the transparent substrate. The low light transmitting portion is formed on the transparent substrate to form a low light transmissive film having a transmittance of light of the representative wavelength of T3 (%).

(Structure 11)

The reticle according to any one of the first aspect of the present invention, characterized in that the transfer mask has a transfer diameter W2 of 3.0 (μm) or less on the transfer target corresponding to the main pattern. W1>W2) hole pattern.

(construction 12)

The configuration 12 of the present invention is the photomask according to the configuration 11, wherein the difference W1 to W2 between the diameter W1 of the main pattern and the transfer diameter W2 on the transfer target is set to be a deviation β (μm). When, 0.2≦β≦1.0‧‧‧(6).

(construction 13)

According to a ninth aspect of the invention, the light-transmitting cover according to any one of the first to the first aspect, wherein the low transmittance portion has a transmittance T3 (%) for the light of the representative wavelength satisfies T3 < 30‧‧ (7).

(construction 14)

The photoreceptor according to any one of the first to tenth aspect of the present invention, wherein the low light transmitting portion does not substantially transmit the light of the representative wavelength.

(construction 15)

The composition 15 of the present invention is a method of manufacturing a display device, comprising the steps of: preparing a photomask according to any one of 1 to 14; using a numerical aperture (NA) of 0.08 to 0.20, and having An exposure apparatus including an exposure light source including at least one of i light, h light, and g light, and exposing the transfer pattern to form a hole pattern having a diameter W2 of 0.6 to 3.0 (μm) on the transfer target .

According to the present invention, it is possible to provide an excellent photomask which is suitable for an exposure environment of a photomask for display device manufacturing and which can stably transfer a fine pattern, and a method of manufacturing the same.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a top plan view showing an example of a reticle of the present invention.

Fig. 2 is a plan view (a) to (f) of another example of the reticle of the present invention.

Fig. 3 shows examples (a) to (f) of the layer constitution of the photomask of the present invention.

4(a) to 4(f) are a schematic cross-sectional view and a plan view showing an example of a manufacturing process of the photomask of the present invention.

Fig. 5 is a plan view showing a reticle of Comparative Examples 1-1 and 1-2 and Example 1, and showing a transfer performance of dimensions and optical simulation.

6 is a view showing a spatial image of (a) light intensity formed on the transfer target when the photomasks of Comparative Examples 1-1 and 1-2 and Example 1 are used, and (b) A diagram of the cross-sectional shape of the formed resist pattern.

Fig. 7 is a plan view showing a reticle of Comparative Examples 2-1 and 2-2 and Example 2, showing a dimensional and optically simulated transfer performance.

8 is a view showing a spatial image of (a) light intensity formed on the transfer target when the photomasks of Comparative Examples 2-1 and 2-2 and Example 2 are used, and (b) A diagram of the cross-sectional shape of the formed resist pattern.

If the CD (Critical Dimension) of the transfer pattern included in the mask is made finer, it is more difficult to accurately transfer it to the transfer target (to be performed) The step of etching the processed film or the like, which is also referred to as a processed body. In the exposure apparatus for a display device, the resolution limit indicated by the specification is usually about 2 to 3 μm. On the other hand, in the transfer pattern to be formed, a size close to this or smaller than this has appeared. Further, since the area of the photoreceptor for manufacturing a display device is larger than that of the photoreceptor for manufacturing a semiconductor device, it is difficult to uniformly transfer the transfer pattern having a CD of less than 3 μm in the plane in actual production.

Therefore, it is necessary to study factors other than the pure resolution (according to the exposure wavelength and the numerical aperture of the exposure optical system), thereby effectively improving the transfer performance.

Further, since the area of the transfer target (flat panel display substrate) is large, the step of transferring the pattern by exposure can also be referred to as an environment in which defocusing due to the flatness of the surface of the transfer target is likely to occur. In this environment, it is extremely meaningful to ensure the focus margin (DOF (DepthofFocus)) during exposure.

Further, as is well known, the size of the photomask for manufacturing a display device is large, and in the wet processing (developing or wet etching) in the photomask manufacturing step, CD (line width) is ensured at all positions in the plane. Uniformity is not easy. In order to control the final CD accuracy within the specified tolerance range, it is also important to ensure a sufficient depth of focus (DOF) in the exposure step, and it is desirable that other properties do not deteriorate.

The present invention is a photomask including a transfer pattern formed on a transparent substrate and patterned by patterning a semi-transmissive film and a low light-transmissive film, respectively. Fig. 1 is a plan view showing a pattern of a transfer pattern of a photomask of the present invention.

As shown in FIG. 1, the transfer pattern formed on the transparent substrate includes a diameter of W1 (μm). The main pattern and the auxiliary pattern disposed in the vicinity of the main pattern having a width d (μm). Further, a low light transmitting portion is formed in a region other than the main pattern and the auxiliary pattern.

Here, the transmittance of the light of the representative wavelength in the wavelength region of the i-ray to g-ray transmitted through the auxiliary pattern is T1, and the transmittance of the light of the representative wavelength transmitted through the low-transmission portion is set to T3. Further, the distance between the center of the main pattern and the center of the auxiliary pattern in the width direction is P (μm). At this time, the photomask of the present invention satisfies the following relationship.

0.8≦W1≦4.0‧‧‧‧‧‧‧‧‧‧‧‧‧ (1)

1.0<P≦5.0‧‧‧‧‧‧‧‧‧‧‧‧‧‧ (3)

T3<T1‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧‧ (4)

In the above formula, T1 is preferably T1≧30.

Here, the light transmittances T1 and T3 are determined based on the transmittance of the transparent substrate, and the layer configuration of the portion is determined.

The cross-sectional pattern diagram of such a transfer pattern can be, for example, as shown in Fig. 3(a). This will be described as a first aspect of the photomask of the present invention, and will be described with reference to FIG. 3(a).

In this aspect, the main pattern includes a light transmitting portion exposed by the transparent substrate. Further, a film having a high transmittance can be formed in the main pattern. However, in terms of obtaining the maximum transmittance, it is preferable to form a film having a high transmittance without forming a film having a high transmittance.

Further, the auxiliary pattern of the aspect includes a semi-transmissive portion formed by forming a semi-transparent film on a transparent substrate. The semi-transmissive film has a phase shift amount that substantially shifts light of a representative wavelength in a wavelength range of i rays to g rays by 180 degrees, and has a transmittance T1 (%) for a representative wavelength. Further, the portion surrounding the main pattern and the auxiliary pattern is a low light transmitting portion in which at least a low light transmissive film is formed on the transparent substrate. That is, in the transfer pattern shown in FIG. 1, the areas of the main pattern and the auxiliary pattern are formed. The outer region becomes a low light transmitting portion. As shown in FIG. 3(a), in this aspect, the low light transmitting portion is formed by laminating a semi-transmissive film and a low light transmitting film on a transparent substrate. Further, the low light transmitting portion may laminate a semi-transmissive film and a low light transmissive film having a transmittance of T2 (%) of light of a representative wavelength on the transparent substrate sequentially or in reverse order.

The low light transmissive portion of the photomask of the present invention has a specific low transmittance with respect to the representative wavelength of the exposed light. That is, for the light of the representative wavelength in the wavelength range of the i-ray to the g-ray, the low-transmission portion has a transmittance T3 (%) which is lower than the transmittance T1 (%) of the auxiliary pattern including the semi-transmissive portion. Therefore, in the present aspect in which the low light transmitting portion is formed by laminating the semi-transmissive portion and the low light transmitting portion (FIG. 3(a)), by the layering, T3<T1 is obtained.

In this way, the transmittance T2 (%) of the low light transmissive film is selected, whereby the transmittance T3 (%) of the low light transmitting portion can be adjusted.

When the diameter (W1) of the main pattern is 4 μm or less, a fine main pattern having a diameter W2 (μm) (where W1 > W2) can be formed on the object to be transferred corresponding to the main pattern ( Hole pattern).

Specifically, it is preferable to make W1 (μm) into the following formula (1)

0.8≦W1≦4.0‧‧‧(1)

Relationship. In this case, the diameter W2 (μm) of the main pattern (hole pattern) formed on the transfer target is 3.0 (μm) or less, and specifically, 0.6 ≦ W2 ≦ 3.0.

Further, the photomask of the present invention can be used for the purpose of forming a pattern of a fine size useful for the display device. For example, when the diameter W1 of the main pattern is 3.0 (μm) or less, the effects of the present invention are more remarkably obtained. Preferably, the diameter W1 (μm) of the main pattern can be set to 1.0≦W1≦3.0‧‧‧‧‧‧‧‧‧‧‧‧ (1)-1

Further, although the relationship between the diameter W1 and the diameter W2 can be set to W1 = W2, it is preferable to set W1 > W2. That is, when β (μm) is set as the deviation value, β = W1 - W2 > 0 (μm), and in this case, 0.2 ≦ β ≦ 1.0, more preferably 0.2 ≦ β ≦ 0.8.

When set in this manner, as described below, an advantageous effect of reducing the loss of the resist pattern on the transferred body can be obtained.

In the above, the diameter W1 of the main pattern means the diameter of the circle, or a value similar thereto. For example, when the shape of the main pattern is a regular polygon, the diameter W1 of the main pattern is set to the diameter of the inscribed circle. If the shape of the main pattern is square as shown in FIG. 1, the diameter W1 of the main pattern is the length of one side. The diameter W2 of the transferred main pattern is also the same in terms of the diameter of the circle or a value similar thereto.

Of course, when it is desired to form a finer pattern, W1 can be set to 2.5 (μm) or less, or 2.0 (μm) or less, and the present invention can be applied to W1 of 1.5 (μm) or less.

Further, the diameter W1 of the main pattern in the photomask of the present invention, the diameter W2 of the main pattern on the transfer target, and the above preferred range relating to the setting of the deviation are in the following second to sixth aspects. The photomask of the invention can also be applied in the same manner.

The phase difference between the main pattern and the auxiliary pattern for the representative wavelength of the exposed light for the exposure of the reticle of the present invention having such a pattern for transfer It is roughly 180 degrees. That is, the phase difference between the representative wavelength of the light passing through the main pattern and the representative wavelength of the transmission auxiliary pattern 1 is roughly 180 degrees. The so-called roughly 180 degrees means 120 to 240 degrees. Phase difference 1 is preferably 150 to 210 degrees, and more preferably 170 to 190 degrees.

Furthermore, the photomask of the present invention is effective when using light including exposure of i rays, h rays, or g rays, so that exposure light including at least one of i rays, h rays, and g rays can be used. It is particularly preferable to use a wide-wavelength light containing i-ray, h-ray, and g-ray as the light for exposure. In this case, as the representative wavelength, any of i rays, h rays, and g rays can be used. For example, the h light can be used as a representative wavelength to constitute the photomask of the present invention.

In order to form such a phase difference, the main pattern is a light-transmissive portion in which the main surface of the transparent substrate is exposed, and the auxiliary pattern is a semi-transmissive portion formed by forming a semi-transparent film on the transparent substrate, and the semi-transparent portion is formed. The phase shift amount of the light film to the above representative wavelength may be set to substantially 180 degrees.

Further, the preferred range of the phase difference between the main pattern and the auxiliary pattern and the wavelength of the light applied to the reticle of the present invention are the same in the photomask of the present invention in the second to sixth aspects below. .

In the reticle of the first aspect, that is, the reticle shown in FIG. 3(a), the light transmittance T1 of the semi-transmissive portion can be set as follows. In other words, when the transmittance of the semi-transmissive film formed in the semi-transmissive portion to the representative wavelength is T1 (%), it is 30 ≦ T1 ≦ 80.

More preferably 40 ≦ T1 ≦ 75.

Further, the transmittance T1 (%) is a transmittance of the above-mentioned representative wavelength when the transmittance of the transparent substrate is used as a reference.

In the reticle of the present invention, it is disposed in an area other than the main pattern and the auxiliary pattern; Further, the low light transmitting portion formed around the main pattern and the auxiliary pattern can be configured as follows.

The low light transmissive portion may also be such that substantially no light that is exposed (light of a representative wavelength in the wavelength range of i rays to g rays) is transmitted. In this case, the low light transmissive film monomer can be applied as a low light transmissive film that does not substantially transmit the above-mentioned representative wavelength (ie, a light shielding film) and has an optical density of OD ≧ 2, or can be The laminated film of the low light transmissive film and the semi-transparent film is set as a substantially light-shielding film (optical density OD ≧ 2).

Alternatively, the low light transmitting portion may be configured to transmit the exposed light within a specific range. However, when the exposed light is transmitted in a specific range, the transmittance T3 (%) of the low light transmitting portion (here, in the case where the semi-transmissive film and the low transparent film are laminated, the laminated film is used) The transmittance) satisfies T3 < T1.

It is preferable to satisfy 0.01 < T3 < 30, and more preferably 0.01 < T3 ≦ 20.

The transmittance T3 (%) is also the transmittance of the above representative wavelength when the transmittance of the transparent substrate is used as a reference.

Further, when the light having the low transmittance is transmitted through the light having a specific transmittance, the phase difference between the transmitted light of the low light transmitting portion and the transmitted light of the light transmitting portion 3 is preferably set to 90 degrees or less, more preferably 60 degrees or less. The phrase "90 degrees or less", if expressed in radians, means that the phase difference is "(2n-1/2) π~(2n+1/2) π (where n is an integer)". Similarly to the above, the phase difference of the representative wavelength included in the exposed light is calculated.

Therefore, in this case, as a separate property of the low light transmissive film for the photomask of the present aspect, it is preferable to have a transmittance (T2 (%)) of less than 30 (%) (that is, 0 < T2 < 30), and the amount of phase shift ( 2) roughly 180 degrees. The so-called roughly 180 degrees means 120 to 240 degrees. Phase difference 1 is preferably 150 to 210 degrees, more preferably 170 to 190 degrees. Thereby, regarding the phase shift characteristic of the low light transmitting portion including the laminate, 3 is set to the above range.

Here, the transmittance is also the same as the above, and the transmittance of the representative wavelength when the transmittance of the transparent substrate is used is set.

In the transfer pattern, when the width of the auxiliary pattern is d (μm),

When it is established, the excellent effect of the invention can be obtained. That is, When ×d is in the above range, the amount of light transmitted through the auxiliary pattern and the amount of light transmitted through the main pattern are well balanced, and the transfer property of the main pattern is improved.

At this time, the distance between the center of the main pattern and the center of the width direction of the auxiliary pattern is set to a pitch P (μm), and the pitch P is preferably 1.0 < P ≦ 5.0.

The relationship is established.

More preferably, the pitch P can be set to 1.5 < P ≦ 4.5.

In the present invention, the auxiliary pattern has an effect of exerting an optical effect like a Dense Pattern with respect to the main pattern designed to be isolated, but the light that is transmitted through the main pattern and the auxiliary pattern when the relationship is satisfied is satisfied. Good interaction with each other can be exhibited, showing excellent transfer properties as shown in the following examples.

The width d (μm) of the auxiliary pattern is the size below the resolution limit in the exposure conditions (exposure means used) applied to the reticle of the present invention, as a specific example, d ≧ 0.7, More preferably, d ≧ 0.8, and further preferably the width d (μm) of the auxiliary pattern is 1 (μm) or more.

Further, it is preferably d ≦ W1, more preferably d < W1.

Further, it is more preferable that the above (2) relational expression is the following formula (2)-1, and further preferably the following formula (2)-2.

As described above, the main pattern of the photomask shown in Fig. 1 is a square, but the present invention is not limited thereto. For example, as illustrated in FIG. 2, the main pattern of the reticle may be a shape including a rotational symmetry of an octagon or a circle. Further, the center of the rotational symmetry can be set to be the center of the reference of the above P.

Further, the shape of the auxiliary pattern of the mask shown in Fig. 1 is an octagonal belt, but the present invention is not limited thereto. It is preferable that the shape of the auxiliary pattern is such that a shape is given a certain width to the shape of the rotating object three times or more symmetric with respect to the center of the hole pattern. Preferably, the shape of the main pattern and the auxiliary pattern are as illustrated in FIGS. 2(a) to (f), and the design of the main pattern and the design of the auxiliary pattern may also be different from those of FIGS. 2(a) to (f). Combine with each other.

For example, the outer circumference of the auxiliary pattern is exemplified by a regular polygon such as a square, a regular hexagon, a regular octagon, or a regular decagon (preferably a positive 2n polygon, where n is an integer of 2 or more) or a circular shape. Further, as the shape of the auxiliary pattern, a shape in which the outer circumference of the auxiliary pattern is substantially parallel to the inner circumference, that is, a shape such as a regular polygon or a circular belt having a certain width is preferable. This strip shape is also referred to as a polygonal belt or a circular belt. As the shape of the auxiliary pattern, it is preferable that such a regular polygonal belt or a circular belt surrounds the shape of the periphery of the main pattern. In this case, the balance between the amount of transmitted light of the main pattern and the amount of transmitted light of the auxiliary pattern can be made substantially equal, and thus it is easy to obtain to obtain the present invention. The interaction of the effects of light.

In particular, when the photomask of the present invention is used as a photomask for manufacturing a display device, that is, when the photomask of the present invention is used in combination with a photoresist for manufacturing a display device, the transfer can be reduced. A part of the resist loss corresponding to the auxiliary pattern.

Alternatively, the shape of the auxiliary pattern may be a shape that does not completely surround the periphery of the main pattern and a portion of the polygonal belt or the circular belt is lacking. For example, the shape of the auxiliary pattern may be a shape in which the corner portion of the quadrangular belt is lacking as shown in Fig. 2(f).

Further, as long as the effects of the present invention are not impaired, other patterns may be additionally used in addition to the main pattern and the auxiliary pattern of the present invention.

Hereinafter, an example of a method of manufacturing a photomask according to this aspect will be described with reference to FIG.

As shown in Fig. 4 (a), a photomask substrate is prepared.

The mask base is formed by sequentially forming a semi-transmissive film and a low-transparent film on a transparent substrate including glass or the like, and further coating the first resist film.

The semi-transmissive film is a film having a transmittance of 30 to 80 (%) when the i-ray, the h-ray, and the g-ray are set to represent a wavelength on the main surface of the transparent substrate. When T1 (%) is used as the transmittance, 30 ≦ T1 ≦ 80), more preferably 40 to 75 (%), and the phase shift amount with respect to the representative wavelength is approximately 180 degrees. According to such a semi-transmissive film, the phase difference of the transmitted light between the main pattern including the light transmitting portion and the auxiliary pattern including the semi-light transmitting portion can be set to substantially 180 degrees. Such a semi-transmissive film shifts the phase of light of a representative wavelength in the wavelength range of i rays to g rays by approximately 180 degrees. As a film forming method of the semi-transmissive film, a known method such as a sputtering method can be applied.

The semi-transmissive film preferably satisfies the above-described transmittance and phase difference, and includes a material capable of wet etching as described below. However, if the amount of side etching generated during wet etching is too large, deterioration of CD accuracy or destruction of the overlying film due to undercut may occur. Therefore, the film thickness is preferably in the range of 2000 Å or less. For example, it is in the range of 300 to 2000 Å, more preferably 300 to 1800 Å. Here, the CD is a Critical Dimension, which is used in the present specification as the meaning of the line width of the pattern.

Further, in order to satisfy these conditions, the refractive index of the representative wavelength (for example, h light) included in the light to be exposed by the semi-transmissive film material is preferably from 1.5 to 2.9. More preferably 1.8~2.4.

Further, in order to sufficiently exert the phase shift effect, it is preferable that the pattern cross section (etched surface) formed by wet etching is nearly perpendicular to the main surface of the transparent substrate.

In consideration of the above properties, the film material of the semi-transmissive film may be a material containing at least one of Zr, Nb, Hf, Ta, Mo, Ti, and Si, or an oxide or nitrogen containing the materials. a material of a compound, an oxynitride, a carbide, or an oxynitride.

A low light transmissive film is formed on the semi-transparent film of the reticle base. As the film formation method, a known method such as a sputtering method can be applied as in the case of the semi-transmissive film.

The low light transmissive film of the photomask base may be a light shielding film that does not substantially transmit the exposed light. Alternatively, it may be set to have a specific low transmittance for the representative wavelength of the exposed light. The low light transmissive film used in the manufacture of the photomask of the present invention has a transmittance T2 (%) lower than the transmittance T1 (%) of the translucent film in the wavelength range of the wavelength range of the i-ray to the g-ray. ). T2 can also be substantially zero (0.01 or less).

On the other hand, when the low light transmissive film can transmit the exposed light, it is required that the transmittance and the phase shift amount of the low light transmissive film to the exposed light can reach the transmittance of the low light transmitting portion of the photomask of the present invention. And the amount of phase shift. Preferably, in the laminated state of the low light transmissive film and the semi-transmissive film, the transmittance T3 (%) of the light representing the wavelength of the exposed light is 0.01 < T3 < 30, preferably 0.01 < T3 ≦ 20 And, in turn, the amount of phase shift 3 is set to 90 (degrees) or less, and more preferably set to 60 (degrees) or less.

As a property of the low light transmissive film alone, it is preferable that the light of the above representative wavelength is not substantially transmitted, or the transmittance (T2 (%)) of less than 30 (%) is obtained (that is, 0 < T2 < 30). Phase shift amount 2) roughly 180 degrees. The so-called roughly 180 degrees means 120 to 240 degrees. Phase difference 1 is preferably 150 to 210 (degrees), more preferably 170 to 190 (degrees).

The material of the low light transmissive film of the reticle base may be Cr or a compound thereof (oxide, nitride, carbide, oxynitride, or oxynitride), or may also contain Mo, W, Ta, Ti. a metal halide or the above compound of the telluride. However, the material of the low light transmissive film of the mask base is preferably a material which can be wet-etched in the same manner as the semi-transmissive film and which has etching selectivity with respect to the material of the semi-transmissive film. That is, it is preferable that the low light transmissive film is resistant to the etchant of the semi-transparent film, and the semi-transmissive film is resistant to the etchant of the low light transmissive film.

The first photoresist film is further coated on the low light transmissive film of the mask substrate. The photomask of the present invention is preferably written by a laser engraving device, thereby forming a photoresist suitable for the laser engraving device. The first photoresist film may be of a positive type or a negative type, and the following description will be made of a positive type.

Next, as shown in FIG. 4(b), the first photoresist film is written by the writing device using the writing pattern based on the transfer pattern (first writing). Then, the first resist pattern obtained by the development is used as a mask, and the low light-transmissive film is wet-etched. Thereby, the area which becomes a low light transmission part is defined, and the area of the auxiliary pattern (low light-transmission film pattern) surrounded by the low light-transmitting part is defined. As the etching liquid (wet etchant) for performing wet etching, a known one suitable for the composition of the low light-transmitting film used can be used. For example, in the case of a film containing Cr, ammonium cerium nitrate or the like can be used as the wet etchant.

Next, as shown in FIG. 4(c), the first resist pattern is peeled off.

Next, as shown in FIG. 4(d), the second resist film is applied over the entire surface including the formed low light transmissive film pattern.

Then, as shown in FIG. 4(e), the second photoresist film is subjected to the second writing to form a shape formed by development. The second resist pattern is formed. The second resist pattern and the low light transmissive film pattern are used as masks, and wet etching of the semi-transmissive film is performed. By this etching (development), a region including the main pattern of the light transmitting portion where the transparent substrate is exposed is formed. Further, the second resist pattern covers the region which is the auxiliary pattern, and has an opening in a region which is a main pattern including the light transmitting portion, and is preferably exposed from the opening at the edge of the low light transmitting film. The writing of the data in the second writing is pre-formed. In this way, it is possible to absorb the misalignment between the first writing and the second writing, and to prevent deterioration of the CD precision of the transfer pattern. This utilizes the effect of the etching selectivity of the films of the low light transmissive film and the semi-transmissive film on the mutual film.

Further, in the reticle of the present aspect, the semi-transmissive film and the low-transparent film may be formed of a material having no etching selectivity and having common etching characteristics, and an etching stopper film may be provided between the two films.

In other words, by performing the shaping of the second resist pattern in the second writing in this manner, when the isolated hole pattern is to be formed on the transfer target, the patterning of the light shielding film and the semi-transmissive film does not cause a positional deviation. Therefore, in the transfer pattern illustrated in FIG. 1, the center of gravity of the main pattern and the auxiliary pattern can be accurately matched.

The wet etchant for the semi-transparent film is appropriately selected depending on the composition of the semi-transmissive film.

Next, as shown in Fig. 4 (f), the second resist pattern is peeled off to complete the photomask of the present invention shown in Fig. 1.

In the production of a photomask for a display device, when an optical film such as a light-shielding film formed on a transparent substrate is patterned, dry etching and wet etching are applied as etching to be applied. Any of them may be employed, and wet etching is particularly advantageous in the present invention. The reason for this is that the size of the photomask used for the display device is relatively large, and thus there are various sizes. In the manufacture of such a reticle, if dry etching using a vacuum chamber is applied, it will result in inefficiency in the size or manufacturing steps of the dry etching apparatus.

However, there is also a problem associated with the application of wet etching in the manufacture of such a photomask. Since the wet etching has the property of isotropic etching, when a specific film is to be etched and eluted in the depth direction, the etching is also performed in a direction perpendicular to the depth direction. For example, when a semi-transmissive film having a film thickness F (nm) is etched to form a slit, the opening of the resist pattern which becomes the etching mask is reduced by only 2F (nm) than the required slit width (ie, When the one side is F (nm)), the thinner the slit is, the more difficult it is to maintain the dimensional accuracy of the opening of the resist pattern. Therefore, it is useful that the width d of the auxiliary pattern is 1 (μm) or more, and preferably 1.3 (μm) or more.

Further, when the film thickness F (nm) is large, since the amount of side etching is also large, it is advantageous to use a film material having a phase shift amount of substantially 180 degrees even if the film thickness is small. The semi-transmissive film has a higher refractive index at this wavelength. Therefore, it is preferred to use a material having a refractive index of 1.5 to 2.9, preferably 1.8 to 2.4, for the above-mentioned representative wavelength to form a semi-transmissive film.

Further, as the photomask of the present invention shown in Fig. 1, in addition to the above-described aspects, the same optical effect is exhibited by a different layer configuration.

The second aspect of the present invention has a layer configuration showing a cross section in Fig. 3(b). The plan view of the reticle is similar to that of the first aspect described above, but the laminated structure at the time of cross-sectional observation is different. That is, in the low light transmitting portion shown in FIG. 3(b), the laminated layers of the low light transmissive film and the semi-transmissive film are reversed in order, and the low light transmissive film is disposed on the substrate side.

In this case, the design of the pattern of the reticle of the present invention or its parameters, the optical effect produced by the same, and the like are the same as those of the first embodiment. As a design pattern, the application pattern shown in FIG. 2 can be applied. The aspects of the variations are also the same. Further, the physical properties of the film material to be used may be the same.

However, in the photomask of the second aspect, the manufacturing method is slightly different from the first aspect in the following aspects, and therefore, the film material to be used may not necessarily be the same as the first aspect.

For example, in the first aspect, as shown in FIG. 4(a), a photomask substrate in which a semi-transparent film and a low-transparent film are laminated is prepared, and a photomask is produced by applying a secondary photolithography step. However, in the second aspect, it is necessary to prepare a photomask substrate on which only a low light transmissive film is formed on a transparent substrate.

Then, the low light transmissive film is first etched to form a low light transmissive film pattern. Then, a semi-transmissive film is formed on the entire surface of the substrate on which the low light transmissive film pattern is formed, and patterned. In this case, it is preferable to select a material which can be patterned by wet etching in the same manner as in the first aspect. However, in this aspect, the low light transmissive film and the semi-transparent film are not necessarily resistant to each other. That is, even if the two films have no etching selectivity, etching can be performed. Therefore, regarding the choice of materials, the degree of freedom is higher than that of the first aspect.

Next, a third aspect of the reticle of the present invention will be described with reference to Fig. 3(c). In this aspect, the top view pattern is also the same as that of FIG. 1, and the design of the pattern or its parameters, and the optical effects produced by the same are the same as those of the first aspect except for the following aspects. As a design pattern, the same applies to the modification of the example shown in FIG. 2.

The mask of the third aspect shown in FIG. 3(c) is different from the masks of the first and second aspects in that the semi-transmissive film has an unrestricted amount of phase shift of light of the above representative wavelength. At approximately 180 degrees, in association with this, the transparent substrate is etched by a certain amount in the main pattern portion. That is, the main pattern of the aspect is partially exposed instead of the main surface of the transparent substrate which becomes the material, and the etched surface formed by etching a certain amount of the etched portion on the main surface is exposed. Further, between the auxiliary pattern in which the semi-transmissive film is formed and the main pattern in which the etched portion is formed, the phase difference between the representative wavelengths of the wavelength range of the i-rays to the g-rays transmitted through each other is adjusted to be substantially 180 degrees. Similarly to the photomasks of the first and second aspects, the low light transmissive portion may have a semitransparent film laminated on the transparent substrate sequentially or in reverse order, and a transmittance of light of a representative wavelength is T2 (%). The structure of the low light transmission film.

In the first aspect or the second aspect, it is necessary to satisfy both the material and the film thickness of the semi-transmissive film. The condition of the transmittance T1 and the phase difference between the transmission wavelengths of the main pattern and the auxiliary pattern are substantially 180 degrees. However, in the mask of the third aspect, there is an advantage that the condition of the transmittance T1 is prioritized. The composition or film thickness of the semi-transparent film can be adjusted according to the etching amount of the main pattern.

In this respect, the phase shift amount of the light of the representative wavelength of the semi-transmissive film of the present embodiment may be 90 degrees or less or 60 degrees or less. The adjustment may be performed such that the phase difference between the representative wavelengths of the transmission main pattern and the auxiliary pattern is substantially 180 degrees, depending on the sum of the amount of etching of the main pattern and the amount of phase shift of the semi-transmissive film.

Further, in the reticle of the third aspect, wet or dry etching is used for etching the transparent substrate, but dry etching is more preferably applied. Further, in the reticle of the present aspect, an etch stop film may be provided between the semi-transmissive film and the low light-transmissive film.

For example, the following steps can be applied: preparing a photomask substrate formed by laminating a semi-transparent film and a low-transparent film on a transparent substrate. First, etching and removing the two films of the main pattern portion, and then etching and etching the transparent substrate. . Next, the low light transmissive film of the auxiliary pattern portion is etched and removed by the second photolithography step, whereby the photomask of the third aspect can be manufactured. In this case, the film material can be set to be the same as the first aspect.

Further, similarly to the relationship between the first aspect and the second aspect, in the photomask of the third aspect, the laminated layers of the semi-transmissive film and the low light-transmissive film may be reversed in order.

Next, a fourth aspect of the photomask of the present invention will be described with reference to Fig. 3(d). In this aspect, the top view mode is also shown in FIG. Similarly to the third aspect, the fourth aspect forms an etched portion on the transparent substrate of the main pattern portion, but unlike the third aspect, the semi-transmissive film is not used, and the transparent substrate (one part of the main surface) of the auxiliary pattern portion is not used. Exposed. Further, by the selection of the etching depth of the main pattern portion, the main pattern and the auxiliary pattern are respectively transmitted in the same manner as the first to third aspects. The phase difference of the wavelength light is approximately 180 degrees.

In the fourth aspect, since the semi-transmissive film is not present in the auxiliary pattern portion, the transmittance (T1) is 100 (%). In this case, the number of film formations can be reduced, whereby the productivity can be improved as compared with the third aspect, and the probability of occurrence of defects can be reduced.

In this case, apply T1=100 (%) to formula (2) and become

That is, 0.5≦d≦1.5‧‧‧(2).

It is preferably d < W1.

Further, the amount of phase shift of the light having the representative wavelength of the low light-transmissive film used in the mask of the fourth aspect need not be substantially 180 degrees, preferably 90 degrees or less. More preferably, it is 60 degrees or less.

In the reticle of the fourth aspect, the design of the pattern shown in FIG. 1, the parameters other than the special description, and the optical effects produced by the same are the same as those of the first embodiment. The style, the same applies to the variants shown in Figure 2. Moreover, the film material used for the low light transmission film or its physical properties may be the same as in the first aspect. In other words, the transmittance of the representative wavelength of the low light transmitting portion is T3 (%), but it may be a structure of a low light transmitting film having a transmittance of light of the representative wavelength of T2 (%) formed on the transparent substrate. That is, it is the case of T2=T3.

Further, the fifth aspect is obtained by inverting the cross-sectional structure of the main pattern and the auxiliary pattern in the fourth aspect (Fig. 3(e)). The main pattern of the fifth aspect is partially exposed of one of the main surfaces of the transparent substrate, and the auxiliary pattern is formed with an etched portion on the main surface of the transparent substrate. That is, instead of forming the etched portion on the transparent substrate in the main pattern portion, the phase difference between the light passing through the representative wavelength of the main pattern and the auxiliary pattern is set to be substantially 180 degrees by etching the transparent substrate of the auxiliary pattern portion. In this case, of course, the pattern of the plan view or the optical effect thereof is also the same as that of the fourth aspect. Also, regarding its manufacturer There is also no particular difference between the method or the applied film. Therefore, the low light transmissive portion of the fifth aspect is a low light transmissive film in which the transmittance of light representing the wavelength is T2 (%) formed on the transparent substrate.

The sixth aspect of the present invention shown in Fig. 3(f) shows the configuration adopted in the first to fifth aspects (in Fig. 3(f), the photomask of the first aspect is representatively used. Section pattern diagram) The possibility of adding a mask pattern. In the case where the low light transmissive film has a substantial transmittance, it is worth considering this aspect.

That is, in the vicinity of the main pattern and the auxiliary pattern, the interference of the opposite phase light is used, but in the region away from the low light transmitting portion of the main pattern and the auxiliary pattern, there is no need to transmit light passing through the low transparent film, but instead There is a risk that the amount of residual film of the resist pattern formed on the transfer target is reduced. In the case where the risk is to be excluded, it is also useful to provide a light-shielding film pattern in a region away from the low-transmission portion of the main pattern and the auxiliary pattern to completely block light.

Therefore, in the present invention, the use of such a light-shielding film pattern is not hindered as long as the effect is not impaired. In addition, the light-shielding film means a film which does not substantially transmit the light to be exposed (light of a representative wavelength of the i-ray to g-ray range) and has an OD (optical density) of 2 or more. As the material, those having chromium (Cr) as a main component can be cited.

The present invention includes a method of manufacturing a display device, comprising the steps of: exposing the photomask of the present invention to an exposure apparatus, and transferring the transfer pattern onto the transfer target to form a hole pattern.

The manufacturing method of the display device of the present invention is first prepared by the above-described photomask of the present invention. Next, an exposure apparatus having a numerical aperture (NA) of 0.08 to 0.20 and having an exposure light source including at least one of i-ray, h-ray, and g-ray is used, and the transfer pattern is exposed to be transferred to the object to be transferred. A hole pattern having a diameter W2 of 3.0 μm or less, preferably 0.6 to 3.0 μm is formed. Furthermore, the exposure light source of the exposure device preferably includes i rays, h rays, and g rays. For exposure, it is usually advantageous to apply equal exposure.

The exposure machine used for transferring the transfer pattern by using the photomask of the present invention is exemplified by the method of performing double projection exposure. In other words, it is used as an exposure machine for LCD (Liquid Crystal Display Unit) (or for FPD (flat panel display), liquid crystal), and its numerical system has a numerical aperture (NA) of 0.08 to 0.15 (coherence factor). (σ) is 0.4 to 0.9), and the light having the exposure light includes at least one of i rays, h rays, and g rays (also referred to as a wide wavelength light source). However, in the case of an exposure apparatus having a numerical aperture NA of 0.10 to 0.20, of course, the present invention can be applied to obtain the effects of the invention.

Further, the light source of the exposure apparatus to be used may be a modified illumination (such as a belt illumination), but the excellent effects of the invention can be obtained even in the case of non-deformation illumination.

In the present invention, a reticle substrate formed by laminating a semi-transmissive film and a low-transparent film (and, if necessary, a light-shielding film) on a transparent substrate is used as the first to third aspects (and the sixth aspect thereof is applied) The raw material of the mask. Further, a resist film is formed on the surface to form a photomask.

The physical properties, film quality, and composition of the semi-transmissive film and the low light-transmissive film are as described above.

That is, the semi-transmissive film of the mask base preferably has a transmittance T1 of 30 to 80 (%) for a representative wavelength in a wavelength range of i rays to g rays. Further, the semi-transmissive film has a film thickness of 1.5 to 2.9 with respect to the representative wavelength and a phase shift amount of substantially 180 degrees. The film thickness of the semi-transmissive film having such a refractive index has a desired phase shift amount even if it is sufficiently thin, so that the wet etching time of the semi-transmissive film can be shortened. As a result, the side etching of the semi-transmissive film can be suppressed.

Further, in all aspects of the reticle of the present invention, it is possible to manufacture using a reticle substrate on which a low light transmissive film is formed.

The low light transmissive film can be used without substantially transmitting light of the above representative wavelength or having a transmittance of less than 30%. Moreover, the low light transmissive film has a representative of the range of i rays to g rays. The phase shift amount of the wavelength is approximately 180 degrees in the masks of the first and second aspects, and is preferably 90 degrees or less, more preferably 60 in the masks of the third, fourth, and fifth aspects. Below the degree.

[Examples]

The transfer performance of the three kinds of masks (Comparative Examples 1-1 and 1-2 and Example 1) shown in Fig. 5 was compared and evaluated by optical simulation. In other words, the three photomasks having the transfer pattern for forming the hole pattern having a diameter of 2.0 μm on the transfer target were subjected to optical simulation for what transfer performance was exhibited when the exposure conditions were collectively set.

(Comparative Example 1-1)

As shown in FIG. 5, the photomask of Comparative Example 1-1 has a pattern of a so-called binary mask including a light-shielding film pattern formed on a transparent substrate. In the reticle of Comparative Example 1-1, the main pattern including the light-transmitting portion where the transparent substrate was exposed was surrounded by the light-shielding portion. The diameter W1 (one side of the square) of the main pattern is 2.0 (μm).

(Comparative Example 1-2)

As shown in FIG. 5, the photomask of Comparative Example 1-2 is a halftone phase shift mask which has a light transmittance (h light) of 5% and a phase shift amount of half of 180 degrees. The light-transmissive film is formed by patterning, and has a main pattern including a light-transmissive portion having a quadrangular shape of one side (diameter) (i.e., W1) of 2.0 (μm).

(Example 1)

As shown in Fig. 5, the photomask of Example 1 has the transfer pattern of the present invention. Here, the main pattern is a square having a side (diameter) (i.e., W1) of 2.0 (μm), and the auxiliary pattern is an octagonal belt having a width d of 1.3 (μm), and the width of the main pattern center and the auxiliary pattern. The distance between the centers, that is, the pitch P is set to 4 (μm).

The auxiliary pattern is formed by forming a semi-transmissive film on a transparent substrate, assuming the light of the first aspect described above Cover. The light transmittance (for h light) of the semi-transmissive film was 70 (%), and the phase shift amount was 180 degrees. Further, the low light transmissive portion surrounding the main pattern and the auxiliary pattern includes a light shielding film (OD>2) that does not substantially transmit the exposed light.

In any of the photomasks of Comparative Examples 1-1 and 1-2 and Example 1, the diameter W2 was 2.0 μm (W1=W2), that is, formed on the object to be transferred. A hole pattern in which the upper diameter W2 is the same as the diameter W1 of the main pattern of the transfer pattern of the photomask. The exposure conditions applied in the simulation are as follows. That is, the exposed light system is set to include a wide wavelength of i-ray, h-ray, and g-ray, and the intensity ratio is set to g-ray: h-ray: i-ray = 1:0.8:1.

The optical system of the exposure apparatus has an NA of 0.1 and a coherence factor σ of 0.5. The film thickness of the positive type resist which obtained the cross-sectional shape of the resist pattern formed on the to-be-transferred body was set to 1.5 micrometer.

Under the above conditions, the performance evaluation of each transfer pattern is shown in Fig. 5 . Moreover, the spatial image of the light intensity formed on the to-be-transferred body and the cross-sectional shape of the resist pattern formed thereby are shown in FIG.

(optical evaluation of the mask)

For example, when a fine light transmissive pattern having a small diameter is transferred, the spatial image formed by the light that has passed through the reticle on the transfer target, that is, the distribution of the transmitted light intensity curve, must be good. Specifically, it is important that the slope of the peak of the transmitted light intensity is steep, rising nearly vertically, and the absolute value of the intensity of the peak is high (when the secondary peak is formed around, the intensity relative to the secondary peak is relatively The ground is high enough).

When the optical performance of the mask is evaluated more quantitatively, the following indicators can be used.

(1) Depth of focus (DOF)

This index is the depth of focus within a range of ±10% with respect to the target CD. If the value of the DOF is high, it is not easily affected by the flattened body (for example, the panel substrate for a display device). With a candid influence, it is possible to form a fine pattern reliably and suppress the CD (line width) deviation.

(2) MEEF (Mask Error Enhancement Factor)

This index is a numerical value indicating the ratio of the Mask CD error to the CD error of the pattern formed on the transfer target, and the lower the MEEF, the lower the CD error of the pattern formed on the transfer target.

(3) Optimal exposure energy Eop (optimum energy)

Among the reticle for manufacturing display devices, Eop is particularly important in evaluation items. It is the amount of light required for exposure to form the size of the pattern to be obtained on the transferred body. Since the size of the mask is large in the manufacture of the display device (for example, a square or a rectangle of about 300 to 1400 mm on one side of the main surface), if a mask having a lower Eop value is used, the scanning exposure speed can be increased, thereby improving production. effectiveness.

When the performance of each sample of the simulation target is evaluated as described above, as shown in FIG. 5, the mask of the first embodiment is excellent in that the depth of focus (DOF) is increased to 55 μm or more, which is superior to the comparative example. The stable transferability of the pattern is displayed. This means that the value of MEEF is small, and also means that the CD of the fine pattern has high precision.

Further, the value of Eop of the photomask of Example 1 was extremely small. This case is shown in the case of the reticle of the first embodiment, and the exposure time does not increase or can be shortened even when a large-area display device is manufactured.

Moreover, referring to the spatial image of the transmitted light intensity shown in FIG. 6, it can be seen that in the case of the photomask of the first embodiment, the main pattern can be made with respect to the level (Eth) which is the threshold value of the resist photosensitive. The increase in the peak of the portion also enables the slope of the peak to rise sufficiently (close to the surface of the transferred body). This aspect is advantageous over Comparative Examples 1-1 and 1-2. Here, the increase in Eop is achieved by increasing the light intensity of the light transmitted through the auxiliary pattern at the position of the main pattern. The reduction in MEEF. Further, in the reticle of the first embodiment, side peaks are generated on both sides of the transfer image position of the main pattern, but since it is equal to or less than Eth, the transfer of the main pattern is not affected.

Further, a method for reducing the loss of the resist residual film caused by the side peak will be described below.

The pattern formed in the transfer pattern of the photomask was changed, and the simulation was performed using the samples shown in FIG. 7 (Comparative Example 2-1, Comparative Example 2-2 and Example 2). Here, each sample was The diameter W1 of the main pattern was set to 2.5 (μm), and was different from the above-described samples (Comparative Example 1-1, Comparative Example 1-2, and Example 1).

(Comparative Example 2-1)

As shown in FIG. 7, the photomask of Comparative Example 2-1 is a so-called binary mask pattern of a light-shielding film pattern formed on a transparent substrate. In the reticle of Comparative Example 2-1, the main pattern including the light-transmitting portion where the transparent substrate was exposed was surrounded by the light-shielding portion. The diameter W1 (one side of the square) of the main pattern is 2.5 (μm).

(Comparative Example 2-2)

As shown in FIG. 7, the photomask of Comparative Example 2-1 is a halftone phase shift mask which has a light transmittance (h light) of 5% and a phase shift amount of half of 180 degrees. The light-transmissive film is formed by patterning, and has a main pattern including a light-transmissive portion of a quadrilateral having a diameter W1 (one side of the square) of the main pattern of 2.5 (μm).

(Example 2)

As shown in Fig. 7, the photomask of the second embodiment is a transfer pattern of the present invention. The main pattern of the reticle of Embodiment 2 is a square having a diameter W1 (one side of a square) of 2.5 (μm), and an auxiliary pattern is an octagon belt having a width d of 1.3 (μm), a center of the main pattern and an auxiliary pattern. The distance P from the center of the width, that is, the pitch P is set to 4 (μm). Here, the reticle of Embodiment 2 also assumes the reticle of the first aspect.

Using the photomasks of Comparative Example 2-1, Comparative Example 2-2, and Example 2, a hole pattern having a diameter of 2.0 μm was formed on the transfer target. That is, the mask deviation (β = W1 - W2) of the masks is set to 0.5 (μm). The exposure conditions applied in the simulation were the same as those of the photomasks of Comparative Examples 1-1 and 1-2 and Example 1 described above.

According to the data shown in Fig. 7, it was confirmed that the excellent DOF and MEEF were exhibited in the case of using the photomask of Example 2, and the advantageous properties for Comparative Examples 2-1 and 2-2 were exhibited. In the reticle of Embodiment 2, in particular, the DOF became a value exceeding 35 μm.

Further, when the spatial image of the transmitted light intensity and the cross-sectional shape of the resist pattern on the transfer target shown in Fig. 8 are used, the excellent characteristics of the sample of the second embodiment are more clearly defined. As shown in Fig. 8, in the case of using the photomask of Example 2, the peak corresponding to the main pattern was significantly higher than the side peaks formed on both sides, and almost no resist damage occurred.

From the above results, it is clear that in the case of pattern transfer using the photomask of the present invention, the transfer pattern having a mask deviation β of about 0.5 (μm), specifically, a range of 0.2 to 1.0 (μm) In this, an excellent transfer image that is easier for practical use can be obtained.

From the above, the excellent performance of the photomask of the present invention can be confirmed. In particular, when the photomask of the present invention is used, it is possible to obtain a value of MEEF of 2.5 or less in a fine pattern of 2 μm or less, which is of great significance in the future manufacture of a display device.

The use of the photomask of the present invention is not particularly limited. The photomask of the present invention can be preferably used in the manufacture of a display device including a liquid crystal display device or an EL display device.

According to the reticle of the present invention, it is possible to control the mutual interference of the light transmitted through both the main pattern and the auxiliary pattern, and to reduce the zero-order light during the exposure, and relatively increase the ratio of the light of ±1 time. Therefore, the spatial image of the transmitted light can be greatly improved.

As a use which can advantageously obtain such an effect, in order to form a liquid crystal or EL It is advantageous to use the photomask of the present invention for an isolated hole pattern such as a contact hole of the device. As a kind of pattern, in many cases, a dense pattern (Dense pattern) in which a plurality of patterns are regularly arranged in a regular manner and which are optically influential with each other, and a pattern in which such a regular arrangement is not present is isolated. The pattern is distinguished by the name. The photomask of the present invention is preferably applied when an isolated pattern is to be formed on the object to be transferred.

It is also possible to use an additional optical film or functional film for the photomask of the present invention within the scope of not impairing the effects of the present invention. For example, in order to prevent a problem that the light transmittance of the low light transmissive film may cause an obstacle to the inspection or the position detection of the photomask, a light shielding film may be formed in a region other than the transfer pattern. Further, in the semi-transmissive film, an anti-reflection layer for reducing the reflection of the engraved light or the exposed light may be provided on the surface thereof.

Claims (24)

A photomask for manufacturing a display device, comprising a transfer pattern formed on a transparent substrate, and having a numerical aperture (NA) of 0.08 to 0.20 and having an i-ray And an exposure device for exposing at least one of h light and g light, a photomask that is transferred onto the transfer target, and the transfer pattern is used to form a pattern of a hole pattern on the transfer target, And a main pattern having a diameter of W1 (μm); an auxiliary pattern having a width of d (μm) disposed in the vicinity of the main pattern; and a light shielding portion constituting a region other than the main pattern and the auxiliary pattern; The auxiliary pattern surrounds the periphery of the main pattern via the light shielding portion, and is in the shape of a regular polygonal strip or a circular strip, and transmits light of a representative wavelength in a wavelength range of the i-ray to g-ray transmitted through the main pattern and transmits the auxiliary pattern. The phase difference of the above-mentioned representative wavelength light is approximately 180 degrees. The reticle of claim 1, wherein the diameter W1 of the main pattern satisfies the following formula (1): 0.8 ≦ W1 ≦ 4.0 ‧ ‧ ‧ ‧ ‧ ‧ ‧ ‧ ‧ (1) The photomask of claim 1, wherein the diameter W1 of the main pattern satisfies the following formula (1)-1: 1.0≦W1≦3.0‧‧‧‧‧‧‧‧‧‧‧‧‧(1)-1 The reticle of claim 3, wherein the width d (μm) of the auxiliary pattern satisfies the following formula (2): The photomask according to any one of claims 1 to 4, wherein when the distance between the center of the main pattern and the center of the auxiliary pattern in the width direction is P (μm), the following formula (3) is satisfied: 1.0< P≦5.0‧‧‧‧‧‧‧‧‧‧‧‧‧ (3) The photomask according to any one of claims 1 to 4, wherein the auxiliary pattern is formed on the transparent substrate to form a semi-transmissive film having a transmittance of light of the representative wavelength of T1 (%). The photomask of claim 6, wherein the transmittance T1 (%) of the semi-transmissive film satisfies the following formula (5): 30 ≦ T1 ≦ 80 ‧ ‧ (5) The reticle according to any one of claims 1 to 4, wherein the width d of the auxiliary pattern is 1 (μm) or more. The photomask of claim 6, wherein the main pattern is formed by exposing a portion of a main surface of the transparent substrate, wherein the auxiliary pattern is formed on the transparent substrate to form the semi-transparent film, and the light shielding portion is transparent The semi-transmissive film and the light-shielding film are laminated on the substrate sequentially or in reverse order. The photomask of claim 6, wherein the main pattern is formed by forming an etched portion on a main surface of the transparent substrate, and the auxiliary pattern is formed on the transparent substrate to form the semi-transparent film, wherein the opaque portion is The semi-transmissive film and the light-shielding film are laminated on the transparent substrate in this order or in reverse order. The photomask of claim 6, wherein the semi-transmissive film comprises a material containing at least one of zirconium, hafnium, tantalum, niobium, molybdenum and titanium and niobium, or an oxide, a nitride, or an oxynitride containing the material. Material, carbide, or material of nitrogen oxides. The photomask of claim 1, wherein the auxiliary pattern is formed by exposing the transparent substrate. The photomask of claim 12, wherein the main pattern is formed by forming an etched portion on a main surface of the transparent substrate, wherein the auxiliary pattern is formed by exposing one of a main surface of the transparent substrate, and the opaque portion is transparent A light shielding film is formed on the substrate. The photomask of claim 12, wherein the main pattern is formed by exposing a portion of a main surface of the transparent substrate, wherein the auxiliary pattern is formed by forming an etched portion on a main surface of the transparent substrate, and the opaque portion is transparent A light shielding film is formed on the substrate. A reticle according to any one of claims 1 to 4, 12 to 14, which corresponds to the above main pattern A hole pattern having a transfer diameter W2 of 3.0 (μm) or less (where W1 > W2) is formed on the transfer target. The reticle of claim 15, wherein when the difference W1 - W2 between the diameter W1 of the main pattern and the transfer diameter W2 on the transfer target is a deviation β (μm), 0.2 ≦ β ≦ 1.0 ‧‧‧(6) The reticle of any one of claims 1 to 4, wherein the auxiliary pattern is in the shape of a regular polygonal strip. The reticle according to any one of claims 1 to 4, wherein the light of a representative wavelength of the wavelength range of the i-rays to the light rays transmitted through the main pattern and the light of the representative wavelength of the auxiliary pattern are transmitted. The phase difference is 180 degrees. The reticle of any one of claims 1 to 4, 12 to 14 for illuminating the reticle by non-deformation illumination using the above-described exposure apparatus. The reticle of any one of claims 1 to 4, wherein the hole pattern is an isolated hole pattern. A manufacturing method of a display device, comprising the steps of: preparing a photomask according to any one of claims 1 to 20; and using a numerical aperture (NA) of 0.08 to 0.20, and having an i-ray, an h-ray, and a g-light In the exposure apparatus of the exposure light source of at least one of the lines, the transfer pattern is exposed, and a hole pattern having a diameter W2 of 0.6 to 3.0 (μm) is formed on the transfer target. A method of manufacturing a display device according to claim 21, wherein said display device is an organic EL display device. A method of manufacturing a display device according to claim 21, wherein the exposure device is an equal-projection exposure device. The method of manufacturing the display device according to claim 21, wherein the homology factor σ of the exposure pattern is set to 0.4 to 0.9.