TW202131091A - Photomask, method of manufacturing a photomask, method of manufacturing a device for a display unit - Google Patents

Abstract

To provide a photomask having an excellent transfer performance and capable of transferring a fine line pattern on a transfer object by exposure using an exposure apparatus. A photomask for use in manufacture of a display unit has a transfer pattern on a transparent substrate. The transfer pattern includes a line pattern. The line pattern has an edge area formed along an outer edge to have a width E, and a center area formed in a portion except the dege area and having a width C. The edge area has a phase shift function of shifting, by about 180 degrees, a phase of exposure light for exposing the photomask and has a transmittance T1(%)(where 0＜T1＜10) with respect to the exposure light. The center area comprises a light transmissive portion or a light semi-transmissive portion.

Description

Photomask, photomask manufacturing method, and display device manufacturing method

The present invention relates to a photomask, a manufacturing method of a photomask, and a manufacturing method of a device for a display device, which are more suitable for manufacturing a display device.

In Patent Document 1, there is described a photomask provided with a pattern for transfer on a transparent substrate. The pattern for transfer has: a light-transmitting portion; A semi-transmissive film; and a light-shielding portion, which is formed with a light-shielding film; and the semi-transparent film has a transmittance of 2-60% to the representative wavelength of the exposure light used for the transfer of the transfer pattern, and 90 For the phase shift effect of less than 1°C, the edge of the semi-transmissive part and the light-shielding part are adjacent to each other, and is formed at a width that is not resolved by the exposure device.

Patent Document 2 describes an exposure method in which light from an exposure light source is incident on an optical system through a halftone mask with a line pattern, and the light passing through the optical system is irradiated onto a glass substrate containing a photosensitive material The photoresist layer is exposed. According to Patent Document 2, an exposure method using a halftone type phase shift mask is provided. The halftone type phase shift mask is more suitable for manufacturing glass substrates such as display panels. The deep focus depth of TFT (Thin Film Transistor) exposure on a large substrate. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2013-235036 [Patent Document 2] Japanese Patent Laid-Open No. 2006-330691

[The problem to be solved by the invention]

For mobile terminals such as smartphones, LCD (Liquid Crystal Display) or organic EL (Electro Luminescence) display devices (so-called flat panel displays: FPD, Flat Panel Display) are used in various parts of society. aspect. For these display devices, the market strongly demands brighter, high-definition images and images. Therefore, a display device (element) with high pixel density and excellent power saving is required.

Along with this trend, the trend of miniaturization of the element patterns formed in the photomasks used to manufacture these elements has become increasingly prominent. In addition, when the exposure mask transfers the transfer pattern to the transfer target body (display panel substrate, etc.), it is necessary to accurately transfer the above-mentioned element pattern.

Generally, the transfer performance of the pattern formed on the transferred body by the exposure of the photomask depends on the optical system of the exposure device. That is, when the CD (Critical Dimension) of the pattern becomes smaller, it is necessary to use a high-resolution exposure optical system, otherwise it cannot be transferred to the transferred body correctly .

Compared with display devices, in the field of semiconductor device (LSI: Large Scale Integration (Large Scale Integration)) manufacturing masks, where the integration is higher and the miniaturization of patterns has made significant progress, there are the following backgrounds: In order to obtain high resolution , And the application uses an optical system with a high number of apertures (NA: Numerical Aperture, such as over 0.2) for the reduced exposure of the exposure device, and promotes the shortening of the wavelength of the exposure light. As a result, in this field, KrF or ArF excimer lasers (single wavelengths of 248 nm and 193 nm, respectively) are used. However, the situation is different in the field of display devices.

Those used in the field of display device manufacturing are equal-magnification projection exposure devices, and the NA of the optical system is about 0.08 to 0.15. In addition, the exposure light source mainly uses an i-line, h-line, or g-line light source. In most cases, a light source containing a plurality of wavelengths (hereinafter, also referred to as a wide-wavelength light source) is used. Thereby, the amount of light used to irradiate a mask having a large area (for example, a side of the main surface is 200-2000 mm, or a quadrilateral of 300-2000 mm) for the manufacture of display devices, etc., can be improved in terms of production efficiency and cost. The advantages are valued.

Generally, if the NA of the optical system is increased, the resolution becomes higher. However, simply replacing the exposure device used in the display device manufacturing field with a device with a larger NA is not necessarily advantageous in terms of cost or technology. For example, changing the exposure device held by it to one with a higher NA means a huge investment for the display panel manufacturer. In addition, an increase in NA also has disadvantages such as a decrease in the depth of focus (DOF: Depth of Focus). Therefore, a photomask for a display device having a larger area than a photomask for LSI manufacturing may cause a decrease in production stability or a decrease in yield.

The pattern for transfer included in the photomask for manufacturing a display device usually includes a line pattern. As an example of the use of the line pattern, FIG. 1 shows the line and space pattern of the previous photomask 100. It has a line pattern including the light-shielding part 101 and a space pattern including the light-transmitting part 102. By preparing a mask base with a light-shielding film formed on a transparent substrate, the light-shielding film is patterned by a well-known photolithography process to form the line and space pattern.

Moreover, in such a line pattern (or line and space pattern), as described above, there is also a strong demand for miniaturization. That is, in a display device to be obtained using a photomask, high-definition and bright (or power-saving) display performance is required. With this requirement, it is necessary to cope with the high density of the photomask pattern and the miniaturization of the CD.

According to Patent Document 1, as the distance between the line and the space pattern becomes smaller, the shape of the photoresist pattern formed on the object to be transferred by the exposure of the photomask tends to deteriorate. Here, the following problem occurs. The transfer pattern of the photomask is not correctly reflected on the photoresist pattern on the transferred body, and the line parts cannot be separated. In response to this problem, Patent Document 1 describes a photomask having a semi-transmissive portion that has a transmittance of 2 to 60% and a phase shift effect of 90 degrees or less.

On the other hand, Patent Document 2 discloses a halftone type phase shift mask with line and space patterns as a mask for obtaining a deep focus depth suitable for exposure of a photoresist of a glass substrate for a display panel.

It is known that halftone type phase shift masks are mainly used in the field of semiconductor device (LSI) manufacturing. By using the phase shift effect of transmitted light, compared with the so-called binary mask, the light intensity distribution during transfer is Contrast or depth of focus is more advantageous. However, the inventors of the present invention believe that the transfer performance of the photomask described in the above-mentioned document is insufficient to cope with the trend of miniaturization, and there is still a further increase in the interval.

For photomasks used in the manufacture of display devices, designs containing line patterns are often used. For example, there are many cases where lines and space patterns in which line patterns are arranged are applied to wiring patterns or pixel electrodes. As described above, in order to obtain high-definition and bright display performance, the miniaturization of such a pattern and the technology that can finely transfer it to the transfer object become important.

For example, when the transfer pattern of the photomask has a line pattern with a specific fine width, or a line and space pattern with a fine pitch width, an exposure device for general display device manufacturing is used for the transfer body (display panel). It is not easy to perform fine pattern transfer on a substrate, etc.). The inventors of the present invention conducted intensive research on the ability to finely transfer such a pattern and obtain a photomask with excellent production stability, and completed the present invention. [Technical means to solve the problem]

The first aspect of the present invention is a photomask, which is a photomask for manufacturing a display device with a pattern for transfer on a transparent substrate; and The above-mentioned transfer pattern includes a line pattern; The above-mentioned line pattern has: an edge area, which is formed along the outer edge with a width E; and a central area of the width C, which is formed in a part other than the above-mentioned edge area; The edge region has a phase shift function that shifts the phase of the exposure light exposed by the mask by approximately 180 degrees, and has a transmittance T1 (%) (where 0<T1<10) for the exposure light; The aforementioned central area includes a light-transmitting part or a semi-light-transmitting part.

The second aspect of the present invention is the mask of the first aspect described above, wherein The width C and the width E satisfy C<E.

A third aspect of the present invention is the photomask of the first or second aspect, wherein the line pattern has a width L (μm), and 1.0≦L≦7.0.

The fourth aspect of the present invention is the photomask of any one of the above-mentioned first to third aspects, wherein The central region includes a light-transmitting portion having a width C1 (μm), 0.1≦C1<2.0, and the transparent substrate is exposed.

The fifth aspect of the present invention is the photomask of any one of the above-mentioned first to third aspects, wherein The central area includes: a semi-transmissive portion with a translucent film formed on the transparent substrate, which has a width C2 (μm), 0.1≦C2<2.0, and has a transmittance T2 (%) for the exposure light ( Where 30≦T2<100).

The sixth aspect of the present invention is the photomask of the above-mentioned fifth aspect, wherein The semi-transmissive film is one that does not substantially have a phase shift effect on the exposure light.

The seventh aspect of the present invention is the photomask of any one of the above-mentioned first to sixth aspects, wherein The transfer pattern has a line and space pattern including the line pattern with a width L and a space pattern with a width S (μm).

The eighth aspect of the present invention is the mask of the seventh aspect, wherein in the line and space pattern, the width L and the width S are L=S.

The ninth aspect of the present invention is the same as the mask of the seventh aspect, wherein In the line and space pattern, the width L and the width S are L>S.

The tenth aspect of the present invention is the photomask of any one of the seventh to ninth aspects, wherein the distance P (μm) between the line and the space pattern is 4.0≦P≦8.0.

The eleventh aspect of the present invention is a method of manufacturing a device for a display device, which includes: The step of preparing a photomask in any of the above-mentioned first to tenth aspects; and The step of exposing the photomask with an exposure device for a display device, and transferring the pattern for transfer to the object to be transferred.

The twelfth aspect of the present invention is a method for manufacturing a photomask, which is a method for manufacturing a photomask for manufacturing a display device with a pattern for transfer on a transparent substrate; and The above-mentioned transfer pattern has: a line and space pattern, which includes a line pattern and a space pattern; and the manufacturing method has the following steps: Prepare a photomask base with a phase shift film formed on the above-mentioned transparent substrate and a photoresist film formed on the outermost surface; Drawing and developing the above-mentioned photomask substrate to form a photoresist pattern; and Patterning the phase shift film using the photoresist pattern to form the first pattern of the line and space pattern; and The phase shift film has a phase shift function that shifts the phase of the exposure light exposed by the mask by approximately 180 degrees, and has a transmittance T1 (%) (where 0<T1<10) for the exposure light; The line pattern has an edge area formed with a width E along the outer edge, and a central area with a width C formed in a portion other than the edge area; The edge region is formed by forming the phase shift film on the transparent substrate; The central area is formed by exposing the transparent substrate.

A thirteenth aspect of the present invention is a method for manufacturing a photomask, which is a method for manufacturing a photomask for manufacturing a display device with a pattern for transfer on a transparent substrate; and The above-mentioned transfer pattern has: a line and space pattern, which includes a line pattern and a space pattern; and the manufacturing method has the following steps: Prepare a photomask base with a phase shift film formed on the above-mentioned transparent substrate and a photoresist film formed on the outermost surface; Drawing and developing the above-mentioned photomask substrate to form a photoresist pattern; Patterning the phase shift film using the photoresist pattern to form a first patterning of the phase shift film pattern; and Patterning the semi-transmissive film formed on the transparent substrate on which the phase shift film pattern is formed to form the second patterning of the line and space pattern; and The phase shift film has a phase shift function that shifts the phase of the exposure light exposed by the mask by approximately 180 degrees, and has a transmittance T1 (%) (where 0<T1<10) for the exposure light; The semi-transparent film has substantially no phase shift effect on the exposure light; The line pattern has an edge area formed with a width E along the outer edge, and a central area with a width C formed in a portion other than the edge area; The edge region is formed by forming the phase shift film on the transparent substrate; The central region is formed by forming the semi-transparent film on the transparent substrate.

The fourteenth aspect of the present invention is the manufacturing method of the mask of the above-mentioned twelfth or thirteenth aspect, wherein The photomask substrate has an etching photomask film between the phase shift film and the photoresist film; In the first patterning step, the etching photomask film is etched using the photoresist pattern as a photomask to obtain the etching photomask film pattern as a photomask, and the phase shift film is patterned.

The fifteenth aspect of the present invention is a method for manufacturing a photomask, which is a method for manufacturing a photomask for manufacturing a display device with a pattern for transfer on a transparent substrate; and The above-mentioned transfer pattern has: a line and space pattern, which includes a line pattern and a space pattern; and the manufacturing method has the following steps: Prepare a photomask base with a semi-transparent film formed on the above-mentioned transparent substrate and a photoresist film on the outermost surface; Drawing and developing the above-mentioned photomask substrate to form a photoresist pattern; Using the photoresist pattern to pattern the semi-transmissive film to form a first pattern of the semi-transparent film pattern; and Patterning the phase shift film formed on the transparent substrate on which the semi-transparent film pattern is formed to form the second patterning of the line and space pattern; and The phase shift film has a phase shift function that shifts the phase of the exposure light exposed by the mask by approximately 180 degrees, and has a transmittance T1 (%) (where 0<T1<10) for the exposure light; The semi-transparent film has substantially no phase shift effect on the exposure light; The line pattern has an edge area formed with a width E along the outer edge, and a central area with a width C formed in a portion other than the edge area; The edge region is formed by forming the phase shift film on the transparent substrate; The central region is formed by forming the semi-transparent film on the transparent substrate.

The sixteenth aspect of the present invention is the same as the method for manufacturing the mask of the fifteenth aspect, wherein The photomask substrate has an etching photomask film between the semi-transparent film and the photoresist film; and In the first patterning step, the etching photomask film is etched using the photoresist pattern as a photomask, so that the obtained etching photomask film pattern is a photomask to pattern the semi-transparent film. [Effects of Invention]

The photomask of the present invention has an excellent transfer performance of transferring a fine line pattern to a transfer object by exposure using an exposure device.

<The first embodiment of the present invention> (1) About mask 1 FIG. 1 shows a photomask 100 (reference example 1) of a known binary mask as described above (a line pattern including a light-shielding portion 101 and a space pattern including a light-transmitting portion 102 are provided on a transparent substrate). In addition, in FIG. 2, instead of the light shielding portion 101 in FIG. 1, a halftone type phase shifting light is formed in which a phase shifting portion 103 (a portion having a specific transmittance for exposure light and a phase shift by approximately 180 degrees) is formed Mask (also known as Attn.PSM) mask 110 (Reference Example 2).

On the other hand, FIG. 3 illustrates the photomask 1 of the present invention having a pattern of lines and spaces on a transparent substrate. The line pattern 10 of the photomask 1 is different from the line patterns of the photomasks of Reference Examples 1 and 2, and has two outer edges along each line pattern, and two edge regions 11 each formed with a width E (μm). In addition, in this specification, the line pattern having an outer edge means one end and the other end in the width direction of the line pattern, and it is not necessarily limited to the entire edge surrounding the line pattern. In addition, the line pattern 10 has a central region 12 with a width C1 (μm) formed in a portion other than the edge region 11. That is, the central area 12 is located between the two edge areas 11 formed along the two ends (side ends) of the line pattern 10 that face each other. Preferably, the central area 12 is sandwiched by the two edge areas 11 and connected to them. In addition, a space pattern 13 having a width S (μm) is formed between two adjacent line patterns 10.

Here, the edge region 11 has a phase shift function that shifts the phase of the exposure light of the exposure mask 1 by approximately 180 degrees. Therefore, the edge region 11 can also be referred to as a phase shift region. Roughly 180 degrees means within a range of 180±20 degrees, more preferably within a range of 180±10 degrees.

In addition, the edge region 11 has a transmittance T1 (%) to exposure light. T1 is 0<T1<10%, and more specifically, it preferably satisfies 4≦T1<7. Here, the transmittance means what is based on the transmittance of the transparent substrate (100%), and the same applies to the following. When the range of the transmittance T1 is the above, it is preferable to produce a balance of the interaction of the exposure light described later, and it is easy to improve the transferability.

Exposure light means light irradiated from a light source provided in an exposure device for manufacturing a display device. For example, light with a wavelength of 300 to 500 nm can be used. In addition, in this specification, "A-B" means the numerical range of "A or more and B or less". As the exposure light, a single wavelength (for example, i-line with a wavelength of 365 nm) may be used, or a light source including a plurality of wavelengths (hereinafter also referred to as a wide-wavelength light source) may also be used. When the exposure light includes a single wavelength, the phase shift or transmittance of the above-mentioned exposure light is for its wavelength, and when a wide-wavelength light source is used, it is for any wavelength contained in the wavelength range of the wide-wavelength light source. (Called the representative wavelength).

The central area 12 shown in the mask 1 of FIG. 3 has a width C1 and is formed in a slot shape. In the first embodiment, this portion is a narrow light-transmitting portion formed by exposing the transparent substrate, and the transmittance of the exposure light is 100%.

The line pattern 10 has a width L (μm), where L=2×E+C1. Moreover, the width L may be 1.0≦L≦7.0.

The width E of the edge region 11 can be set to 0.4≦E≦2.0, more specifically, 0.8≦E≦1.8.

In addition, the width C1 of the central region 12 can be set to 0.1≦C1<2.0, more specifically, it can be set to 0.5≦C1≦1.5. Here, the width C1 and the width E are preferably C1<E. Furthermore, the ratio (C1/L) of the width C1 to the width L is preferably 0.05 to 0.4, more specifically 0.15 to 0.3, and furthermore, when it is set to 0.2 to 0.3, the effect of improving the DOF described later is better. The advantages.

The width C1 of the central region 12 is preferably set to a fine width smaller than the width E and smaller than the width S.

In addition, when it is considered that the ratio of the width of the space pattern 13 through which the exposure light passes and the width of the central region 12 affects its interaction, the ratio of the width C1 to the width S (C1/S) is preferably 0.05 to 0.8, more specifically When it is 0.1 to 0.7, and further 0.3 to 0.6, excellent optical properties can be obtained.

That is, it is preferable to arrange such a narrow slot (central area 12) in the center of the width direction of the line pattern 10, and to sandwich it from both sides by the edge area 11. The width C1 of the central area 12 is smaller than the resolution limit of the exposure device used for manufacturing the display device, and therefore cannot be independently transferred to the transferred body. However, the inventors have discovered that when the line pattern 10 (or line and space pattern) is transferred, it exerts an excellent effect in a plurality of evaluation items indicating its transfer performance. Here, the center in the width direction of the line pattern 10 means that the center in the width direction of the slot (central region 12) coincides with the center in the width direction of the line pattern 10, but it also includes occurrence within the range of ±10 nm. Position shift situation.

FIG. 3 shows a line and space pattern in which the above-mentioned line pattern 10 is regularly arranged. The line and space pattern is as described above, and the line pattern 10 of the width L and the space pattern 13 of the width S are alternately and regularly arranged. The width S can be set to 0.3≦S≦3.5, more specifically, it can be set to 0.8≦S≦3.0.

The repeating pitch P (μm) of the line and space pattern is preferably set to 4.0≦P≦8.0. When the pitch P is greater than 8.0 μm, even the previous masks 100 and 110 (binary masks, Attn.PSM) can achieve a certain degree of transferability, so the effect of the present invention is not significant. On the other hand, if the pitch P is less than 4.0 μm, the design of the central area 12 that can be processed tends to become difficult.

Here, the width L and the width S can be set to L=S, or can also be set to L≠S. For example, it can be set to L>S, or it can be set to L<S. In Figure 3, the situation where L>S is shown. That is, the range of the ratio (S/L) of the width S to the width L can be set to 0.2 to 1.0, more specifically 0.3 to 0.9, and when it is set to 0.3 to 0.7, the following can be obtained more significantly Favorable optical properties such as DOF.

Here, in the transfer pattern of the photomask 1, the case of L>S has an advantage in the following situations. That is, the transferred body (display panel substrate) after the pattern transfer using the above-mentioned photomask 1 is developed, and the formed photoresist pattern is used as the photomask to be attached in the etching step. In the case of wet etching, side etching is performed on the etched object to be processed (such as a thin film of electrode material, etc.), so it is advantageous to make the width L slightly larger than the final target size in advance.

Regarding the optical function of the photomask 1, when the simulation described later is performed, compared with the photomask 110 of Reference Example 2, extremely advantageous results can be obtained in terms of several characteristics.

Hereinafter, the optical simulation performed to verify the function of the photomask 1 of the present invention will be described.

Here, the photomask used in the simulation has a line and space pattern with a pitch P of 6 μm, and is a sample photomask of the photomask 1, which is represented as the model (Type)1(a)~(e) in FIG. 6.

The optical simulation conditions are based on the premise that the equal-magnification projection exposure device used for the display device is used, and the conditions shown in Fig. 5 are applied. Moreover, when the photomask 1 with the above-mentioned line and space pattern is exposed, the cross-sectional shape of the photoresist pattern formed on the body to be transferred (shown in FIG. 5) is obtained, and a plurality of parameter values indicating transferability are obtained . Show it in Figure 6.

In addition, the initial film thickness of the photoresist (positive type) was set to 1400 nm. In addition, the line and space pattern of the photomask 1 is formed by patterning a phase shift film with an exposure light transmittance of 5.2% and a phase shift amount of 180 degrees (both based on the i-line) on a transparent substrate. The width C1 of the central region 12 formed at the center of the width direction of the line pattern is described as Qz Slit (C1) in FIG. 6. At this time, the following conditions are set: at the bottom of the photoresist pattern formed on the body to be transferred, lines and spaces of the same size as the transfer pattern of the photomask 1 are transferred.

The evaluation items are as follows.

Eop (mJ/cm ² ) Eop refers to the amount of exposure light used to obtain a transfer image of the target size on the transferred body. Eop is preferably smaller. Here, Eop is the amount of exposure light used to form a pattern of lines and spaces of the same size as the pattern for transfer of the mask on the body to be transferred.

Side tilt angle of photoresist pattern θ (degrees) As shown in FIG. 5, the inclination angle θ of the side surface of the photoresist pattern represents the inclination angle of the side surface of the photoresist pattern formed on the transferred body in the cross section. That is, it means the angle formed by the main surface of the transparent substrate (the surface on which the phase shift film is formed) and the side surface of the photoresist pattern formed on the body to be transferred. The inclination angle θ of the side surface of the photoresist pattern is preferably larger (close to 90 degrees).

DOF (Depth of Focus) DOF means depth of focus. Here, the size of the focal depth used to obtain the accuracy within the range of ±10% relative to the target CD is set as DOF. If the value is large, the CD of the pattern on the transferred body is not easily affected by the flatness of the surface of the transferred body, etc., and CD unevenness can be reduced.

EL (Exposure Latitude: exposure margin) EL means exposure margin. Here, the margin of exposure used to obtain the accuracy within ±10% of the target CD is set to EL. The larger the EL, the better.

MEEF (Mask Error Enhancement Factor: Mask Error Enhancement Factor) MEEF is a numerical value representing the ratio of the CD error of the mask to the CD error of the transferred image formed on the transferred body. The lower the value, the more the CD error of the pattern formed on the transferred body can be reduced . In addition, the CD error here means the difference between the target CD and the pattern CD on the mask or the transferred body.

NILS (Normalized Image Log Slope: Normalized Image Log Slope) NILS is the one that normalizes the edge slope of the photoresist pattern (the slope of the side surface of the photoresist pattern in the cross-section) formed on the transferred body, and the value is preferably larger.

It is clear from Fig. 6 that if compared with Reference Example 2 (Attn.PSM without slot line and space pattern), the performance of each evaluation item is equal or higher. In particular, in the sample masks (models 1(a) to (e)) of all mask 1, the display DOF is 25 μm or more. In the display device manufacturing, the process margin is relatively large.

In addition, the reduction of the Eop value is very advantageous as an exposure condition for the mask used in the manufacture of a display device with a larger exposure area, which indicates that the productivity can be further improved.

Furthermore, the side inclination angle θ is closer to vertical, indicating that CD unevenness in the plane can also be suppressed. In addition, the DOF exceeds 25 μm, and is significantly improved compared to the mask 110 of Reference Example 2.

In addition, it is obvious that the MEEF decreases and the NILS increases.

As described above, the excellent effects of the photomask 1 of the present invention have been confirmed.

It is considered that the principle for obtaining such an effect is as follows. If the line and space pattern of a general binary mask is exposed, the light intensity distribution on the object to be transferred by the light passing through the space pattern part forms a wave peak. In the case of Attn.PSM, the contrast is improved, but the peak height is slightly lowered.

In contrast, the photomask 1 of the present invention allows the light passing through the slit (central region 12) formed in the center of the width direction of the line pattern 10 to interact well with the light passing through the spacer pattern 13, thereby increasing the height of the above-mentioned peaks. , And the contrast enhancement effect is exerted due to the phase shift effect.

In addition, according to the cross-sectional view of the photoresist pattern shown in FIG. 5, it can be seen that there are depressions in the center of the upper surface of the photoresist corresponding to the line pattern 10. The inventor further studied the hypothesis that the depression (thickness loss of the photoresist pattern) must be suppressed as much as possible. As a result, it was found that by making the transmittance of the central region 12 less than 100%, an effect can be obtained. The mask 2 is shown in FIG. 4.

(2) About mask 2 The photomask 2 shown in FIG. 4 can be obtained by setting the transmittance T2 (%) of a part of the central region 12 to the exposure light to 30≦T2<100. For example, what is necessary is just to form the center area|region 12 as a part in which the semi-transmissive film which has a desired transmittance|permeability is formed on a transparent substrate.

Here, it is preferable to use the semi-transparent film which is different from the so-called phase shift film and does not substantially have a phase shift function (it does not have the function of reversing the phase of the exposure light). Specifically, the phase shift amount ϕ of the semi-transparent film with respect to the above-mentioned exposure light is preferably set to 90 degrees or less, for example, in the range of 5 to 90 degrees. The phase shift amount ϕ is more preferably 60 degrees or less, and still more preferably within a range of 30 degrees or less.

For the mask 2 used in the following simulation, the central area 12 is set as a semi-transmissive part with a transmittance T2 of 55% (i-line reference), and the central area 12 does not have a phase shift effect (a phase shift amount of 0 degrees) . In addition, when designing the pattern of the mask 2, the value range of the width L, the width S, the width E, and the width C1 in the mask 1 and the range of the value mutual ratio can be applied to the width of the mask 2 respectively. The value of L, width S, width E, and width C2.

In addition, in the mask 2, since the transmittance T2 of the central area 12 is less than the transmittance (100%) of the central area 12 of the mask 1, the width C2 can be set to obtain the same degree of light transmittance. It is slightly wider than the width C1, thereby reducing the difficulty of processing the fine width. In this case, for example, the ratio of the width C2 to the width L (C2/L) can be set to 0.2 to 0.4, and the ratio of the width C2 to the width S (C2/S) can be set to the range of 0.5 to 1.0 Inside.

As mentioned above, another advantage of the photomask 2 lies in the shape of the photoresist pattern formed on the transferred body. In the case of mask 2, the following items will be evaluated.

RPT (Residual Photoresist Thickness) and PR Loss (Photoresist Loss) In the part corresponding to the center of the line pattern, the influence of the center depression of the photoresist pattern on the transferred body was evaluated. If the recesses are too large, the etching process using the photoresist pattern may be hindered, and if the depth of the recesses becomes larger, there is a defect that in-plane unevenness occurs at the depth.

FIG. 7 shows the simulation results of the mask 2 performed in the same manner as the mask 1 described above. Here, the photomask used in the simulation is the sample photomask of the photomask 2, which is represented as model 2(b), 2(c) in FIG. 7. According to Figure 7, the photoresist pattern of mask 2 (models 2(b), 2(c)) has a larger RPT than the photoresist pattern of mask 1 (models 1(b), 1(c)). PR Loss is small. That is, it can be seen that the dimples generated in the center portion of the line width direction of the photoresist pattern formed on the transferred body (the position corresponding to the center region 12 of the photomask 2) are smaller than that of the photomask 1.

FIG. 8(a) illustrates the photoresist pattern of the photomask 1, and FIG. 8(b) illustrates the photoresist pattern of the photomask 2. From this, it can be seen that the photoresist pattern of the photomask 2 has a shape in which the recesses in the central part are greatly reduced compared with the photoresist pattern of the photomask 1.

(3) About the manufacturing method of display device components The present invention includes a method for manufacturing a display device using the above-mentioned photomask 1 and photomask 2. That is, the photomask 1 or the photomask 2 is prepared, the photomask is used to expose the exposure device for the display device, the transfer pattern is transferred to the transferred body, and the display device (or the configuration thereof) is manufactured by applying the above steps. element).

The exposure device used is a projection exposure method, and the NA is 0.08-0.20, and the coherence factor σ is about 0.5-1.0. The exposure light source can be those with wavelengths including i-line, h-line or g-line. Of course, broad-wavelength light including any wavelength of i-line, h-line, or g-line can also be used. In addition, it is preferable to use equal magnification exposure.

(4) Manufacturing method of photomask 1 and 2 Hereinafter, a method of manufacturing the photomask 1 and the photomask 2 will be described with reference to FIGS. 9(a) to (h).

As shown in FIG. 9(a), a photomask base 20 with a phase shift film 22 and a photoresist film 24 formed on a transparent substrate 21 is prepared. The photoresist film 24 can use either a positive photoresist or a negative photoresist, but a positive photoresist is used here. An additional film can also be used within a range that does not impair the function of the present invention. In this embodiment, the etching mask film 23 is interposed between the phase shift film 22 and the photoresist film 24. It has the function of improving the adhesion with the photoresist film 24 and improving the wet etching accuracy of the phase shift film 22. The phase shift film 22 or the etching mask film 23 can be formed using a well-known film forming device such as a sputtering method.

The material of the phase shift film 22 is not particularly limited. When the etching mask film 23 is used, it is preferable to have an etching characteristic (etch selectivity) different from that of the etching mask film 23. As the material of the phase shift film 22, for example, a material containing any one of Zr, Nb, Hf, Ta, Mo, Ti and Si, or oxides, nitrides, oxynitrides, carbides, etc. of these materials can be used. Or carbon oxynitride materials. As a more specific film material, a silicide containing Mo or Zr is cited.

As the etching mask film 23, an etchant for the phase shift film 22 can be used, preferably one having higher adhesion to a photoresist (for example, a positive photoresist) than the material of the phase shift film 22. The etching mask film 23 can be made of Cr or its compound (oxide, nitride, carbide, oxynitride, or oxycarbonitride), for example.

As shown in FIG. 9( b ), drawing and developing are performed on the photoresist film 24 to form a photoresist pattern 25. A laser drawing device can be used for drawing. Next, a photoresist pattern 25 having openings is formed in the area to be the spacer pattern 13 and the area to be the central area 12.

As shown in FIG. 9(c), the etching photomask film 23 is patterned by using the photoresist pattern 25 as a photomask to form an etching photomask film pattern. Next, using the photoresist pattern 25 and/or the etching photomask film pattern as a photomask, the phase shift film 22 is patterned. Thereby, a phase shift film pattern is formed (first patterning step). When the photomask substrate 20 does not include the etching photomask film 23, it is only necessary to use the photoresist pattern 25 as a photomask to pattern the phase shift film 22. Also, although not shown, after the photoresist pattern 25 is peeled off, the phase shift film 22 can be patterned using only the etching photomask film pattern as a photomask. For the patterning of the etching mask film 23 and the phase shift film 22 of this embodiment, either wet etching or dry etching can be applied, but wet etching is preferred.

As shown in FIG. 9(d), the photoresist pattern 25 is peeled off, or the photoresist pattern 25 is peeled off and the photomask film pattern is etched, and the photomask 1 is formed. In the mask 1, the edge area 11 is formed by forming a phase shift film 22 on the main surface of the transparent substrate 21, and the central area 12 is formed by exposing the main surface of the transparent substrate 21. The line pattern of the mask 1 includes the edge area 11 and the central area 12.

As shown in FIG. 9(e), when the mask 2 is to be obtained, the semi-transparent film 26 is formed on the entire surface of the transparent substrate 21 having the patterned phase shift film 22 (phase shift film pattern). The sputtering method or the like can also be applied to this film formation. As the semi-transparent film 26 is as described above, it is preferable to use one that does not substantially have a phase shift effect.

As the material of the semi-transparent film 26, it is desirable to have an etching selectivity with the phase shift film 22. In the case where the phase shift film 22 is the above-exemplified case, as the material of the semi-transmissive film 26, Cr or its compound (oxide, nitride, carbide, oxynitride, or oxycarbonitride) can be used .

As shown in FIG. 9(f), a photoresist film 27 is further coated and formed on the uppermost surface. Here, the case of using a positive photoresist film is also shown as an example.

As shown in FIG. 9(g), the photoresist film 27 is drawn again using a laser drawing device or the like and developed to form a photoresist pattern 28 in which the photoresist remains in the central region 12.

As shown in FIG. 9(h), the photoresist pattern 28 is used as a photomask, and the useless semi-transparent film 26 is removed by wet etching (the second patterning step), and then the photoresist pattern 28 is peeled off to obtain a photomask 2 . In the mask 2, the edge area 11 is formed by forming a phase shift film 22 on the main surface of the transparent substrate 21, and the central area 12 is formed by forming a translucent film 26 on the main surface of the transparent substrate 21. The line pattern of the mask 2 includes the edge area 11 and the central area 12. In the edge area 11 of the mask 2, only the phase shift film 22 is formed on the transparent substrate 21. In addition, in the central area 12 of the mask 2, only the semi-transparent film 26 is formed on the transparent substrate 21. That is, the line pattern of the photomask 2 does not include the layered portion of the phase shift film 22 and the semi-transparent film 26.

In the above-mentioned manufacturing method of the photomasks 1 and 2, the case of using the photomask base 20 with the phase shift film 22 formed on the transparent substrate 21 has been described, but the present invention is not limited to this. For example, it is also possible to prepare a photomask base 20 with a translucent film 26 formed on the transparent substrate 21 instead of the phase shift film 22, and a photoresist film formed on the outermost surface, and to perform drawing and development on the photomask base 20 to form The photoresist pattern is used to pattern the semi-transparent film 26 using the formed photoresist pattern, so that after the semi-transparent film pattern is formed (the first patterning step), the semi-transparent film pattern is formed on the transparent substrate The phase shift film 22 is formed, and the phase shift film 22 is patterned to form a line and space pattern (second patterning step). That is, when using the photomask base 20 with the translucent film 26 formed on the transparent substrate 21, it is only necessary to reverse the phase shift film 22 and the translucent film 26 in the above-mentioned manufacturing method of the photomask 1 and 2 Just replace it. In addition, the photomask substrate 20 may have an etching photomask film between the semi-transparent film 26 and the photoresist film. In this case, in the first patterning step, the photoresist pattern can also be a photomask and the etching photomask film can be etched to obtain the etching photomask film pattern as a photomask, or the photoresist pattern and the photomask can be used for etching. The mask pattern is that the semi-transparent film 26 is patterned by the mask. The use of the photomask illustrated by the photomask 1 and the photomask 2 is not particularly limited. However, the purpose of the photoresist pattern formed on the transferred body using the photomask illustrated by the photomask 1 and the photomask 2 is the two-dimensional (on the plane) design formed by the bottom CD of the photomask 1, and the photomask 1, The exemplified photomask of the photomask 2 is different from the so-called multi-grayscale photomask. The multi-gray-scale photomask here means a photomask that has halftones and is used to make the thickness (height) of the photoresist pattern formed on the transferred body vary from region to region (that is, to form a three-dimensional design).

Moreover, the photomask of the present invention can be advantageously used for wiring patterns or pixel patterns of display devices that require fine line and space patterns.

The embodiments of the present invention have been described in detail above, but the present invention is not limited to the above-mentioned embodiments, and various changes can be made without departing from the spirit of the present invention.

1: photomask 2: photomask 10: Line pattern 11: Edge area 12: Central area 13: Interval pattern 20: Mask base 21: Transparent substrate 22: Phase shift film 23: Etching mask film 24: photoresist film 25: photoresist pattern 26: semi-transparent film 27: photoresist film 28: photoresist pattern 100: mask 101: Shading part 102: Translucent part 103: Phase shift part 110: Mask C1: width C2: width E: width L: width P: Pitch RPT: Residual photoresist thickness S: width θ: Side tilt angle of photoresist pattern

FIG. 1 is a schematic top view of the previous photomask 100. As shown in FIG. FIG. 2 is a schematic top view of the previous photomask 110. As shown in FIG. FIG. 3 is a schematic top view of the mask 1 of the present invention. FIG. 4 is a schematic top view of the mask 2 of the present invention. 5 is a schematic cross-sectional view of the photoresist pattern of the optical simulation of the photomask 1 of the present invention. FIG. 6 is a diagram showing the result of the optical simulation of the mask 1 of the present invention. FIG. 7 is a diagram showing the result of the optical simulation of the mask 2 of the present invention. FIG. 8 (a) is a schematic diagram of the photoresist pattern of the optical simulation of the photomask 1 of the present invention, and (b) is a schematic diagram of the photoresist pattern of the optical simulation of the photomask 2 of the present invention. 9(a) to (h) are schematic cross-sectional views for explaining an example of the manufacturing method of the masks 1 and 2 of the present invention.

1: photomask

10: Line pattern

11: Edge area

12: Central area

13: Interval pattern

C1: width

E: width

L: width

P: Pitch

S: width

Claims (16)

A photomask, which is a photomask for manufacturing a display device with a pattern for transfer on a transparent substrate; and The above-mentioned transfer pattern includes a line pattern; The above-mentioned line pattern has: an edge area, which is formed along the outer edge with a width E; and a central area of the width C, which is formed in a part other than the above-mentioned edge area; The edge region has a phase shift function that shifts the phase of the exposure light exposed by the mask by approximately 180 degrees, and has a transmittance T1 (%) (where 0<T1<10) for the exposure light; The aforementioned central area includes a light-transmitting part or a semi-light-transmitting part. Such as the photomask of claim 1, wherein the above-mentioned width C and the above-mentioned width E satisfy C<E. Such as the photomask of claim 1 or 2, wherein the line pattern has a width L (μm), and 1.0≦L≦7.0. Such as the photomask of claim 1 or 2, wherein the above-mentioned central area includes: a light-transmitting part having a width C1 (μm), 0.1≦C1<2.0, and the above-mentioned transparent substrate is exposed. The photomask of claim 1 or 2, wherein the central area includes: a semi-transmissive portion with a semi-transmissive film formed on the transparent substrate, which has a width C2 (μm), 0.1≦C2<2.0, and is The exposure light has a transmittance of T2 (%) (where 30≦T2<100). The photomask of claim 5, wherein the semi-transmissive film is one that does not substantially have a phase shift effect on the exposure light. The photomask of claim 1 or 2, wherein the above-mentioned transfer pattern has a line and space pattern, which includes the above-mentioned line pattern with a width L and a space pattern with a width S (μm). Such as the photomask of claim 7, wherein in the line and space pattern, the width L and the width S are L=S. Such as the photomask of claim 7, wherein in the line and space pattern, the width L and the width S are L>S. Such as the photomask of claim 7, wherein the distance P (μm) between the above-mentioned line and space patterns is 4.0≦P≦8.0. A method for manufacturing a display device component, which includes the following steps: Prepare the photomask of any one of the requirements 1～10; and The photomask is exposed by an exposure device for a display device, and the transfer pattern is transferred to the transfer target body. A method for manufacturing a photomask, which is a method for manufacturing a photomask for manufacturing a display device with a pattern for transfer on a transparent substrate; and The above-mentioned transfer pattern has: a line and space pattern, which includes a line pattern and a space pattern; and the manufacturing method has the following steps: Prepare a photomask base with a phase shift film formed on the above-mentioned transparent substrate and a photoresist film formed on the outermost surface; Drawing and developing the above-mentioned photomask substrate to form a photoresist pattern; and Patterning the phase shift film using the photoresist pattern to form the first pattern of the line and space pattern; and The phase shift film has a phase shift function that shifts the phase of the exposure light exposed by the mask by approximately 180 degrees, and has a transmittance T1 (%) (where 0<T1<10) for the exposure light; The line pattern has an edge area formed with a width E along the outer edge, and a central area with a width C formed in a portion other than the edge area; The edge region is formed by forming the phase shift film on the transparent substrate; The central area is formed by exposing the transparent substrate. A method for manufacturing a photomask, which is a method for manufacturing a photomask for manufacturing a display device with a pattern for transfer on a transparent substrate; and The above-mentioned transfer pattern has: a line and space pattern, which includes a line pattern and a space pattern; and the manufacturing method has the following steps: Prepare a photomask base with a phase shift film formed on the above-mentioned transparent substrate and a photoresist film formed on the outermost surface; Drawing and developing the above-mentioned photomask substrate to form a photoresist pattern; Patterning the phase shift film using the photoresist pattern to form a first patterning of the phase shift film pattern; and Patterning the semi-transmissive film formed on the transparent substrate on which the phase shift film pattern is formed to form the second patterning of the line and space pattern; and The phase shift film has a phase shift function that shifts the phase of the exposure light exposed by the mask by approximately 180 degrees, and has a transmittance T1 (%) (where 0<T1<10) for the exposure light; The semi-transparent film has substantially no phase shift effect on the exposure light; The line pattern has an edge area formed with a width E along the outer edge, and a central area with a width C formed in a portion other than the edge area; The edge region is formed by forming the phase shift film on the transparent substrate; The central region is formed by forming the semi-transparent film on the transparent substrate. The method for manufacturing a photomask according to claim 12 or 13, wherein the photomask substrate has an etching photomask film between the phase shift film and the photoresist film; In the first patterning step, the etching photomask film is etched using the photoresist pattern as a photomask, and the obtained etching photomask film pattern is a photomask, and the phase shift film is patterned. A method for manufacturing a photomask, which is a method for manufacturing a photomask for manufacturing a display device with a pattern for transfer on a transparent substrate; and The above-mentioned transfer pattern has: a line and space pattern, which includes a line pattern and a space pattern; and the above-mentioned manufacturing method has the following steps: Prepare a photomask base with a semi-transparent film formed on the above-mentioned transparent substrate and a photoresist film formed on the outermost surface; Drawing and developing the above-mentioned photomask substrate to form a photoresist pattern; Using the photoresist pattern to pattern the semi-transmissive film to form a first pattern of the semi-transparent film pattern; and Patterning the phase shift film formed on the transparent substrate on which the semi-transparent film pattern is formed to form the second patterning of the line and space pattern; and The phase shift film has a phase shift function that shifts the phase of the exposure light exposed by the mask by approximately 180 degrees, and has a transmittance T1 (%) (where 0<T1<10) for the exposure light; The semi-transparent film has substantially no phase shift effect on the exposure light; The line pattern has an edge area formed with a width E along the outer edge, and a central area with a width C formed in a portion other than the edge area; The edge region is formed by forming the phase shift film on the transparent substrate; The central region is formed by forming the semi-transparent film on the transparent substrate. The method for manufacturing a photomask according to claim 15, wherein the photomask substrate has an etching photomask film between the semi-transparent film and the photoresist film; and In the first patterning step, the etching photomask film is etched using the photoresist pattern as a photomask, so that the obtained etching photomask film pattern is a photomask to pattern the semi-transparent film.

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