KR101408580B1 - Photomask, producing method for photomask, pattern transfer method, manufacturing method for pixel electrode for display device and manufacturing method for display device - Google Patents

Abstract

A predetermined transfer pattern including a line and space pattern is transferred to a resist film formed on a workpiece to be etched and a resist film is used as a resist pattern to be a mask in the etching process, A line pattern of line-and-space patterns formed on the substrate is formed by a translucent portion, and a space pattern is formed by a translucent portion.

Description

TECHNICAL FIELD [0001] The present invention relates to a photomask, a photomask manufacturing method, a pattern transfer method, a method of manufacturing a pixel electrode for a display device, and a manufacturing method of a display device. FOR DISPLAY DEVICE}

The present invention relates to a photomask used in a photolithography process, a method of manufacturing a photomask, a method of transferring a pattern, and a method of manufacturing a liquid crystal display device.

At present, there are VA (Vertical Alignment) method and IPS (In Plane Switching) method as a method adopted for a liquid crystal display device. By applying these methods, it is possible to provide an excellent moving image that provides quick response of the liquid crystal and provides a sufficient viewing angle. Further, by using a line-and-space pattern (line and space pattern) made of a transparent conductive film, the response speed and the viewing angle can be improved for the pixel electrode portion of the liquid crystal display device to which these methods are applied.

In recent years, in order to further improve the response speed and the viewing angle of the liquid crystal, the linewidth of the line and space pattern (CD (Critical Dimension) is in the direction of miniaturization (Japanese Patent Application Laid-Open No. 2007-206346 (Patent Document 1)).

Generally, a photolithography process is used to form a pattern of a pixel portion or the like of a liquid crystal display device. In the photolithography process, a predetermined pattern is transferred to a resist film formed on a body to be etched by using a photomask, and the resist film is developed to form a resist pattern. Then, Thereby etching the processed body. For example, a so-called binary mask is used as a photomask for forming a pixel electrode in a comb shape (forming a line and space pattern in a transparent conductive film). The binary mask is a two-tone photomask comprising a light-shielding portion (black) for shielding light and a light-transmitting portion (back) for transmitting light by patterning a light-shielding film formed on the transparent substrate. In the case of forming a line and space pattern using a binary mask, a line pattern formed on the transparent substrate can be formed by the light shielding portion, and the space pattern can be formed by the transparent portion.

However, if the line width (pitch width) of the line-and-space pattern is reduced, the intensity of the transmitted light irradiated onto the resist film formed on the workpiece through the light transmitting portion of the photomask is lowered and the contrast is lowered. . As a result, there arises a problem that etching of the workpiece becomes difficult. Particularly, if the pitch width of the line-and-space pattern is smaller than 7 占 퐉, the etching conditions of the workpiece become severe and the patterning becomes difficult. Here, the pitch width is a dimension of a repetitive unit when lines and spaces are repeated.

As a method of increasing the resolution and performing finer patterning, application of a numerical aperture enlargement, a short-wavelength exposure, and a phase shift mask of an exposure machine, which have been conventionally developed as techniques for manufacturing LSIs, are considered. However, when these techniques are applied, enormous investment and technological development are required, and the price can not be matched with the price of the liquid crystal display provided in the market. It is also conceivable to increase the intensity and amount of the transmitted light by increasing the exposure amount in the photolithography step. However, in order to increase the exposure amount, it is necessary to raise the output of the light source of the exposure machine or to increase the exposure time, Or the production efficiency is lowered. Therefore, there is little need for additional investment, and a method of performing fine patterning is desired.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide a photomask and a photomask manufacturing method capable of patterning without requiring additional investment even when a line and space pattern with a small pitch width is formed on a workpiece , A pattern transfer method, and a manufacturing method of a liquid crystal display device.

One aspect of the photomask of the present invention is a method for transferring a predetermined transfer pattern including a line and space pattern to a resist film formed on a workpiece to be etched and transferring the resist film to a resist A line pattern of a line and space pattern formed on a transparent substrate is formed by a translucent portion and a translucent portion formed by patterning a translucent film formed on a transparent substrate by a transfer pattern, And a space pattern is formed by the transparent portion. According to this configuration, even when the pitch width of the line-and-space pattern is reduced, the strength of the transmitted light irradiated to the resist film through the transparent portion can be suppressed from being lowered. As a result, fine patterning can be performed on the workpiece with little additional investment.

In one embodiment of the photomask of the present invention, when the transmittance of the transparent portion with respect to the exposure light is 100%, the transmittance of the translucent portion with respect to the exposure light is preferably 1% or more and 30% or less.

In an embodiment of the photomask of the present invention, the effect of the present invention is remarkable when the pitch width of the line-and-space pattern is 2.0 mu m or more and less than 7.0 mu m.

In the embodiment of the photomask of the present invention, when the line width of the line and space pattern formed on the transparent substrate is LM, the space width is SM, the line width of the line and space pattern formed on the workpiece after etching is LP, When the space width is SP, it is preferable that the relationship LM > LP and SM < SP is satisfied.

In the embodiment of the photomask of the present invention, when the line width LP and the space width SP of the line-and-space pattern formed on the workpiece are equal, the line width LM and the space width It is desirable that SM satisfies the relation of LM > SM.

In one embodiment of the photomask of the present invention, assuming that a bias value is 1/2 of the difference between the line width LM and the space width SM of the line and space pattern formed on the transparent substrate, the bias value is 0.2 mu m to 1.0 mu m .

An aspect of the pattern transfer method of the present invention includes the steps of forming a resist film on a workpiece, irradiating the resist film with exposure light through a photomask, developing the resist film to form a resist pattern, And a step of forming at least a part of the workpiece in a line-and-space pattern by etching the workpiece using the photomask as a mask. Any one of the photomasks described above is used as the photomask.

In one aspect of the pattern transfer method of the present invention, when the line width of the line and space pattern of the photomask is LM and the space width is SM, the line width LP of the line and space pattern formed in the workpiece after etching is LM, and the space width SP is preferably larger than SM.

In one aspect of the pattern transfer method of the present invention, when the line width LP and the space width SP of the line-and-space pattern formed on the workpiece are formed with equal widths, the line width LM of the line- Is preferably larger than the width SM.

In one aspect of the pattern transfer method of the present invention, it is preferable to carry out wet etching as etching. When wet etching is performed, it is preferable to use, as the resist film, a material in which the etching selection ratio with respect to the workpiece in the wet etching is 10 times or more.

One aspect of the method for manufacturing a liquid crystal display device of the present invention forms a comb-like pixel electrode by etching a transparent conductive film using any of the above-described pattern transfer methods.

One aspect of the method for manufacturing a photomask of the present invention is a method for transferring a predetermined transfer pattern including a line and space pattern to a resist film formed on a workpiece to be subjected to etching and transferring the resist film to a mask A step of forming a translucent film on the transparent substrate and a step of forming a transfer pattern comprising the transparent portion and the translucent portion by patterning the translucent film, When the transmittance is 100%, the transmittance of the translucent film is set to 1% or more and 30% or less, a line pattern of the line and space pattern formed on the transparent substrate is formed by the translucent portion, .

In one embodiment of the method for producing a photomask of the present invention, it is preferable that the pitch width of the line-and-space pattern is formed to be 2.0 mu m or more and 7.0 mu m or less.

In one aspect of the method for manufacturing a photomask of the present invention, the correlation between the exposure conditions, the characteristics of the resist film, the characteristics of the workpiece, and the processing conditions of the workpiece is defined. Based on the processing conditions of the workpiece, It is preferable to determine the line width and space width of the line and space pattern formed on the substrate and the transmittance of the translucent film of the translucent portion by simulation.

According to one aspect of the present invention, in a line and space pattern formed in a photomask, a line pattern is formed by a translucent portion and a space pattern is formed by a transparent portion, so that when the pitch width of the line- , It is possible to suppress the decrease in the intensity of the transmitted light irradiated to the resist film through the light transmitting portion. Thereby, it is possible to provide a photomask, a photomask manufacturing method, a pattern transfer method, and a manufacturing method of a liquid crystal display device which can perform fine patterning on a workpiece without requiring additional investment.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view for explaining a photomask and a photolithography process using the photomask. Fig.
Fig. 2 is a view showing the effective transmittance of the photomask when the line pattern is formed by the light shielding portion. Fig.
3 is a view showing the effective transmittance of a photomask when a line pattern is formed by a translucent portion.
4 is a diagram showing the effective transmittance of a photomask when a line pattern is formed by a translucent portion.
5 is a diagram showing a cross-sectional shape of a resist film exposed by using a photomask formed by a light shielding portion with a line pattern after development.
6 is a view showing a cross-sectional shape of a resist film exposed by using a photomask formed by a light shielding portion with a line pattern after development.
7 is a view showing a cross-sectional shape of a resist film exposed after exposure using a photomask formed by a translucent portion of a line pattern.
8 is a view showing a cross-sectional shape of a resist film exposed after exposure using a photomask formed by a translucent portion of a line pattern.
9 is a view showing a cross-sectional shape of a resist film exposed by exposure using a photomask formed by a translucent portion of a line pattern.
10 is a view showing a cross-sectional shape of a resist film exposed by exposure using a photomask formed by a translucent portion of a line pattern.
11 is a view showing a cross-sectional shape of a resist film exposed by exposure using a photomask formed by a translucent portion of a line pattern.
12 is a view showing a cross-sectional shape of a resist film exposed by using a photomask formed by a translucent portion of a line pattern after development.

Hereinafter, a photomask and a pattern transfer method using the photomask will be described with reference to Fig. 1 shows a case where an object to be processed 103 formed on a substrate 107 is etched. That is, a predetermined transfer pattern including a line and space pattern formed on the photomask 100 is transferred to the resist film 104 formed on the workpiece 103, and the developed resist pattern 105 is etched And a mask for processing is used.

<Photomask>

The photomask 100 has a predetermined transfer pattern including a line and space pattern and transfers a predetermined transfer pattern including the line and space pattern to the resist film 104 formed on the workpiece 103 . The transfer pattern of the photomask 100 can be formed by the translucent portion 101 and the transparent portion 102 formed by patterning the translucent film formed on the transparent substrate 110. [ Further, a line pattern of line and space patterns of the photomask 100 is formed by the translucent portion 101, and a space pattern is formed by the transparent portion 102.

In the case where the line and space pattern of the photomask is formed by the light shielding portion and the light projecting portion as in the prior art, the pitch width of the line and space pattern becomes small (approaching the resolution limit of the exposure machine) The intensity of the transmitted light to be irradiated on the film is lowered and the contrast of the transmitted light corresponding to the light shielding portion and the light transmitting portion is lowered so that the resist film of the portion exposed through the light transmitting portion remains after the development. As a result, there arises a problem that patterning of the workpiece can not be performed. In order to solve this problem, it is necessary to increase the intensity of transmitted light by decreasing the resolution limit (increasing the resolution) of the exposure apparatus, increasing the applied exposure dose, shortening the wavelength of the exposure light, or applying a phase shift mask I think.

1, the line pattern of the photomask 100 is formed by the translucent portion 101 instead of the light shielding portion, even when the pitch width of the line and space pattern of the photomask 100 is small It is possible to suppress the decrease of the intensity of the transmitted light irradiated to the resist film 104 through the transparent portion 102 (space pattern) and to remove the exposed resist film 104 through the transparent portion 102 after development have. This is because, by forming the line pattern by the translucent portion 101, the same effect as that of increasing the exposure amount in the photolithography process can be obtained. Thus, it becomes possible to form a desired fine pattern at an exposure amount applicable in the photolithography process (without changing the exposure amount or at a smaller exposure amount).

In other words, when the width of the transparent portion 102 such as a line-and-space pattern is reduced, the exposure light transmitted through the transparent portion formed in this slit shape is attenuated by diffraction or the like. In the present invention, It is possible to supplement the diffracted light from the translucent portion to the exposure light attenuated when the translucent portion is diffracted by diffracting the exposure light transmitted through the translucent portion formed of the semitransparent film.

The pitch width of the line-and-space pattern of the photomask 100 is preferably 2.0 mu m or more and less than 7.0 mu m. In the conventional method, a fine pattern having a pitch width of less than 7.0 mu m is excellent in terms of the response speed and brightness of the liquid crystal, and the electric field formed when the liquid crystal display device is used is excellent. In the case of the photolithography process There is a problem in that it is not possible to avoid a problem that arises. On the other hand, according to the method of the present invention, the aforementioned problems can be solved in a fine pattern as described above close to the resolution limit of the exposure machine, and a remarkable effect is obtained. When the pitch width is 2 占 퐉 or more, the light transmittance of the semitransparent film is selected so that a sufficient light intensity can be obtained as the exposure amount of the portion corresponding to the light transmitting portion.

The phase difference generated in the translucent portion 101 is not particularly limited. This is because the present invention can obtain a superior resolution improving effect as a line and space pattern for manufacturing a liquid crystal display device, without depending on the phase inversion or shift of the exposure light. Further, in the selection of the semitransparent film, when the phase difference from the transparent portion is 30 degrees or more and 180 degrees or less in absolute value, a suitable film thickness is obtained and a proper effective transmittance is easily obtained. The more preferable phase difference is an absolute value of 30 degrees or more and 90 degrees or less.

When the photomask 100 shown in Fig. 1 is used, since the resist film 104 is exposed not only through the transparent portion 102 (space pattern) but also through the translucent portion 101 (line pattern) The film thickness t ₁ of the resist pattern 105 in the resist film 104 becomes smaller than the initial film thickness value t ₀ of the resist film 104. When the film thickness t ₁ of the resist pattern 105 becomes too small, a trouble occurs in the etching process (the resist pattern 105 disappears and the film does not function as a mask) The transmittance of the semitransparent film is preferably set in consideration of the intensity of the transmitted light of the transparent portion 102 and the film thickness of the resist pattern 105. [ For example, when the transmittance of the transparent portion 102 of the photomask 100 is 100% with respect to the exposure light, the transmittance of the translucent portion 101 of the translucent portion 101 to the exposure light is preferably 1% to 30% % Or less, more preferably 1% or more and 20% or less, and still more preferably 3% or more and 20% or less. In this range, even when the pitch width of the line-and-space pattern of the photomask 100 is reduced, the intensity of the transmitted light of the transparent portion 102 is prevented from being lowered and the film thickness t ₁ can be left in an amount required for etching. It is to be noted that the transmittance of the transparent portion 102 of the photomask 100 is 100% when the transmittance at the transparent portion (a transparent portion of 20 μm or more in all directions) sufficiently wide in the photomask 100 is 100% Point.

&Lt; Pattern transfer method >

Next, a pattern transfer method using the above-described photomask 100 will be described.

First, a positive resist film 104 is formed on a work piece 103, and exposure light is irradiated to the resist film 104 through the photomask 100 ) Reference). In this case, the resist film 104 is irradiated with exposure light through the transparent portion 102 and the translucent portion 101. Next, the resist film 104 is developed to form a resist pattern 105 (FIG. 1 (b)), and the workpiece 103 is etched using the resist pattern 105 as a mask, At least a part of the workpiece 103 can be formed in a line and space pattern (see Figs. 1 (c) and 1 (d)).

In a pattern transfer method described in the first photomask, because formed using a semi-shielding portion 101 be non-light-shielding a line pattern of 100, the thickness t ₁ of the resist film (104 of the resist pattern 105 after development Lt; ₀ &gt;). Therefore, it is preferable that the etching of the member to be processed 103 is performed using wet etching. When the dry etching is used, the resist pattern 105 is also etched. Therefore, when the thickness of the resist pattern 105 is small, there is a risk that the resist pattern 105 serving as a mask is lost during etching.

On the other hand, in the case of using wet etching, even if the film thickness of the resist pattern 105 is small by increasing the etching selectivity ratio between the material to be processed 103 and the resist material used for the resist film 104, The resist pattern 105 can be prevented from being lost. In order to effectively suppress the disappearance of the resist pattern 105 during the etching process, the etching selectivity ratio of the wet etching of the work 103 to the etchant is 10 times (1:10) or more , Preferably 50 times (1: 50) or more.

Even when the film thickness t ₁ of the resist pattern 105 is small, the shorter the etching processing time of the workpiece 103, the less the resist pattern 105 is lost during the etching process. For example, when the thickness of the workpiece 103 is small, the etching processing time can be shortened. The film thickness of the material to be processed 103 is determined in consideration of the etching conditions and the like. As an example, the etching time can be shortened by forming the material to be processed 103 at a thickness of 40 nm or more and 150 nm or less. As described above, the pattern transfer method shown in this embodiment is particularly effective for patterning a workpiece having a small film thickness. When the film thickness of the workpiece 103 is small, the transmittance of the semitransparent film of the semitransmissive portion 101 of the photomask 100 can be set high. Thereby, the exposure amount of the exposure light in the photolithography process can be lowered.

When the wet etching is applied as the etching of the member to be processed 103, the member to be processed 103 is isotropically etched as compared with the dry etching. That is, at the time of etching, the side surface of the nonselective portion 108 overlapping with the resist pattern 105 is also etched (side etching) (see FIG. 1 (c)). Therefore, when the line width (the width of the translucent portion 101) of the line and space pattern of the photomask 100 is denoted by LM and the space width (width of the transparent portion 102) is denoted by SM, The line width LP of the line and space pattern formed on the sieve 103 becomes smaller than LM, and the space width SP becomes larger than SM.

Therefore, when the line width LP and the space width SP of the line and space pattern formed in the work 103 are set to the same width (LP? SP), the line width LM of the photomask 100 is set to be larger than the space width SM (LM > SM). For example, bias portions 106a and 106b are formed on both sides of the line pattern (translucent portion 101) of the photomask 100 in consideration of a margin such that the nonspecific portion 108 is etched side by side during etching processing can do. The bias portions 106a and 106b can be formed of the same material as the semitransparent film forming the line pattern. The width (bias value) of the bias portions 106a and 106b may be set based on the etching conditions of the workpiece 103. For example, the line width LM of the photomask 100 and the space width SM The bias value can be set to 0.2 mu m to 1.0 mu m.

In addition, the above-described pattern transfer method can be applied to various electronic device manufacturing methods such as a liquid crystal display device. For example, when a pixel electrode is formed in a strip shape (comb shape) in a liquid crystal display device, a transparent conductive material such as indium tin oxide (ITO) is formed by using a photomask 100 having a line- The pattern can be transferred to the film. In this case, a transparent conductive film such as ITO corresponds to the workpiece 103. Therefore, the photomask of the present invention is preferable for transferring the ITO conductive film pattern having a line-and-space pattern with a pitch width of less than 7.0 mu m and 2.0 mu m or more.

As described above, the resist pattern on the object to be processed formed by the method of the present invention, as shown in the simulation result of the cross-sectional shape of the resist in Figs. 7 and 8, increases as the transmittance of the translucent portion increases, The upper portion of the resist cross-section tends to have a more gentle shape. As a method for preventing this tendency, the surface of the resist can be hardened before developing the resist. As a specific method, for example, a resist-coated surface modification layer can be formed on the resist surface by performing vacuum drying after application of the resist.

&Lt; Method of manufacturing photomask >

A predetermined transfer pattern including a line and space pattern of the photomask 100 can be formed by patterning a semi-light-transmitting film formed on the transparent substrate 110. [ At this time, the portion of the photomask 100 in the form of a line pattern of the line and space pattern is formed as a translucent portion 101 by leaving a translucent film formed on the transparent substrate 110, The film may be removed to form the transparent portion 102.

When the transmittance of the transparent portion 102 of the photomask 100 is 100%, the transmittance of the translucent portion 101 as a line pattern is preferably 1% or more and 30% or less, more preferably 1% or less Or more and 20% or less, more preferably 3% or more and 20% or less, and still more preferably 3% or more and 15% or less. The transmittance of the transparent portion 102 of the photomask 100 is 100% when the transmittance of the transparent portion (a light transmitting portion of 20 μm or more in all directions) is 100% which is sufficiently wide in the photomask 100.

The width (line width LM) of the translucent portion 101 of the line and space pattern of the photomask 100 and the width (space width SM) of the transparent portion 102 are formed in the workpiece 103 Can be determined based on the line width LP and the space width SP of the line and space pattern. For example, when the line width LP and the space width SP of the line and space pattern formed in the work 103 are equal, the line width LM of the photomask 100 is larger than the space width SM (LM > SM). This is because, as described above, when the etching process is performed using the resist pattern 105 as a mask, the line width &quot; LP &quot; of the line and space pattern formed in the workpiece 103, Is smaller than the line width LM of the photomask 100.

The ratio of the line width LM of the photomask 100 to the space width SM is set to be larger than the space width SM of the photomask 100 by a width corresponding to the margin in which the nonspiced portion 108 is etched side- It is sufficient to add bias portions to both sides of the pattern (translucent portion 101). As described above, when a half value of the difference between the line width LM and the space width SM of the photomask 100 is a bias value, the bias value can be set to 0.2 mu m to 1.0 mu m. For example, when a line-and-space pattern having a bias value of 0.5 占 퐉 and a pitch width of 5 占 퐉 (line width LM and space width SM of 2.5 占 퐉, respectively) is to be formed on the workpiece 103, The line width LM of the substrate 100 can be set to 3.0 mu m, and the space width SM can be set to 2.0 mu m.

In the production of the photomask 100, the correlation between the exposure conditions, the characteristics of the resist film, the characteristics of the workpiece, the processing conditions of the workpiece, The configuration of the photomask 100 may be designed based on the processing conditions using simulation. As the exposure conditions, the wavelength of the exposure light, NA (numerical aperture) of the imaging system,? (Coherence), and the like may be considered. As the characteristics of the resist film, the development conditions of the resist, the resistance to the etchant, and the like may be considered. As the characteristics of the workpiece 103, etching conditions (type of etchant, temperature) of the workpiece may be taken into consideration. As the processing conditions of the workpiece 103, the shape (line width LP and space width SP) of the line and space pattern formed in the workpiece may be considered.

The photomask 100 is designed under the design conditions (transmittance of the semitransparent film used for the semitransmissive portion 101) and the transmittance of the semitransmissive film used for the semitransparent portion 101 by performing simulation based on the processing conditions of the workpiece 103 to be fabricated, The width (line width LM) of the semitransmissive portion 101 and the width (space width SM) of the transparent portion 102 are obtained and the manufacturing time of the photomask 100 can be greatly shortened.

Further, the present invention is not limited to the above-described embodiment, but can be appropriately changed and carried out. For example, the material, the pattern configuration, the number of members, the size, the processing procedure, and the like in the above embodiment are merely an example, and various modifications can be made within the scope of the present invention. It is possible to appropriately change and carry out the present invention without departing from the scope of the present invention.

<Examples>

Hereinafter, results obtained by simulation will be described in the case where a line pattern of a line and space pattern is formed by a semi-transparent portion and a resist film is exposed using a photomask formed by a transparent portion. The present invention is not limited to the following examples.

First, the conditions used in the embodiment will be described.

Exposure conditions: NA = 0.08, sigma = 0.8, exposure wavelength (intensity ratio of spectrum: g line / h line / i line = 1.0 / 1.0 / 1.0)

Resist Film: Positive-Novolak Type

Initial film thickness of resist film: 1.5 탆

The simulation software was Sentaurus Lithography ( ^TM ) software manufactured by Synopsys (Synopsys).

Next, the photomask used in the embodiment will be described.

&Lt; Example 1 >

Bias part: + 0.5㎛

(Line width: 3.5 占 퐉, space width: 2.5 占 퐉), 5.0 占 퐉 (line width: 3.0 占 퐉, space width: 2.0 占 퐉), 4.4 占 퐉 Width: 1.7 탆)

Transmittance of line pattern: 3% to 20%

&Lt; Example 2 >

Bias part: + 0.8㎛

(Line width: 3.3 mu m, space: 2.7 mu m), 6.0 mu m (line width: 3.8 mu m, space width: 2.2 mu m) Width: 1.7 탆)

Transmittance of line pattern: 3% to 20%

&Lt; Comparative Example 1 &

Bias part: + 0.5㎛

(Line width: 4.5 占 퐉, space width: 3.5 占 퐉), 7.0 占 퐉 (line width: 4.0 占 퐉, space width: 3.0 占 퐉), 6.0 占 퐉 Width: 2.5 占 퐉), 5.0 占 퐉 (line width: 3.0 占 퐉, space width: 2.0 占 퐉), 4.4 占 퐉 (line width: 2.7 占 퐉,

Transmittance of line pattern: 0%

&Lt; Comparative Example 2 &

Bias part: + 0.8㎛

(Line width: 4.8 mu m, space width: 3.2 mu m), 7.0 mu m (line width: 4.3 mu m, space width: 2.7 mu m) Width: 2.2 占 퐉), 5.0 占 퐉 (line width: 3.3 占 퐉, space width: 1.7 占 퐉), 4.4 占 퐉 (line width: 3.0 占 퐉,

Transmittance of line pattern: 0%

First, the relationship between the position of the mask when the exposure light is irradiated and the effective transmittance of the transmitted light with respect to the photomask in which the line and space pattern is formed will be described. In the present invention, the effective transmittance refers not only to the transmittance inherent to the film, but also to factors (such as dimensions or line widths (CD) and optical conditions (optical wavelength, numerical aperture, sigma value) (The effective transmittance that transmits the photomask and determines the amount of light to be irradiated) reflecting the actual exposure environment. For example, in the present specification, the term "transmissivity of the translucent portion" Quot; transmittance of the semitranslucent film &quot; means the effective transmittance described above, and the transmittance in the case of &quot; transmittance of the semitransparent film of the semitranslucent portion &quot;

Fig. 2 shows the effective transmittance of transmitted light when a photomask (binary mask) in which a line pattern is formed with a light-shielding film of zero transmittance is used. 2 (a) shows the case where the bias portion formed on the light-shielding film is 0.5 占 퐉 (Comparative Example 1), Fig. 2 (b) shows the case where the bias portion formed on the light- 2 (c) is a schematic diagram of a line and space pattern used in the simulation. As shown in FIG. The bias portion was formed by using the same material as the film forming the line pattern. 2 (a) and 2 (b), the horizontal axis shows the position of the line and space pattern formed on the mask, and the vertical axis shows the effective transmittance of the transmitted light.

It can be seen from FIG. 2 that as the pitch width of the line-and-space pattern decreases, the effective transmittance of the transmitted light in the transparent portion of the photomask is remarkably reduced.

Figs. 3 and 4 show the effective transmittance of transmitted light when a photomask in which a line pattern is formed by a semitransparent film is used. Fig. 3 shows the case where the bias portion formed on the semitransparent film is 0.5 mu m (Embodiment 1), and Fig. 4 shows the case where the bias portion formed on the semitransparent film is 0.8 mu m (Embodiment 2). 3 (a) to 3 (c) show the case where the pitch width of the line and space pattern is 6.0 占 퐉 (Fig. 3 (a)) and the pitch width is 5.0 占 퐉 (B) of FIG. 4), and FIG. 4 (a) to FIG. 4 (c) (Fig. 4 (c)) when the pitch width is 6.0 [micro] m (Fig. 4 (b)).

3 and 4, it can be seen that the effective transmittance of the light transmitting portion increases as the transmittance of the semi-light transmitting film of the semi-light transmitting portion increases.

Next, the cross-sectional shape of the resist pattern when the resist film is exposed and developed using a photomask having a line and space pattern will be described.

Figs. 5 and 6 show cross sections of the resist pattern after development in the case of using a photomask (binary mask) in which a line pattern is formed by a light-shielding film of zero transmissivity. Fig. 5 shows the case where the bias portion formed on the light-shielding film is 0.5 mu m (Comparative Example 1), and Fig. 6 shows the case where the bias portion formed on the light-shielding film is 0.8 mu m (Comparative Example 2). 5 (a) to 6 (e) and 6 (a) to 6 (d) show the case where the pitch width of the line and space pattern is 8.0 占 퐉 (Fig. 5 (c) and Fig. 6 (c)), when the pitch width is 7.0 탆 (Figs. 5 (b) and 6 (Fig. 5 (d) and Fig. 6 (d)) and the pitch width is 4.4 m (Fig. 5 (e)).

5 and 6 show the cross-sectional shape of the resist pattern after development in the case where the intensity of the exposure light (that is, the exposure amount, the same shall apply hereinafter) is fixed (100 mJ) (mJ is equal to mJ /

5, it was confirmed that when the pitch width of the line-and-space pattern is relatively large (8.0 탆, 7.0 탆), the resist film of the portion irradiated through the light transmitting portion can be removed by the exposure light of 100 mJ, When the pitch width of the space pattern was 6.0 mu m or less, it was confirmed that the resist film remained. The intensity of the exposure light required to completely remove the resist film was determined. When the pitch width of the line and space pattern was 6.0 m, the mobility was 106.7 mJ, the pitch width was 5.0 m and the pitch width was 4.4 m It was necessary to irradiate an exposure light of 148.2 mJ.

6, it was confirmed that when the pitch width of the line-and-space pattern was 8.0 탆, the resist film of the portion irradiated through the light transmitting portion could be removed by the exposure light of 100 mJ. However, It was confirmed that the resist film remained at 7.0 μm or less. When the intensity of the exposure light required to completely remove the resist film was determined, it was found to be 104.6 mJ when the pitch width of the line and space pattern was 7.0 m, 117.4 mJ when the pitch width was 6.0 m, and 5.0 m, It was necessary to irradiate an exposure light of 148.2 mJ.

Figs. 7 to 12 show cross sections of the resist pattern after development in the case of using a photomask in which a line pattern is formed by a semitransparent film. 7 to 9 show the case where the bias portion formed on the semitransparent film is 0.5 m (Example 1), and Figs. 10 to 12 show the case where the bias portion formed on the semitransparent film is 0.8 m (Example 2 As shown in Fig. Figs. 7 and 11 show the case where the pitch width of the line and space pattern is 6.0 m, Figs. 8 and 12 show the case where the pitch width is 5.0 m, Fig. 9 shows the case where the pitch width is 4.4 m, And a width of 7.0 mu m.

7 to 12 show cross sections of the resist pattern after development when the transmittance of the translucent film of the translucent portion forming the line pattern is changed. However, Figs. 7 to 12 show cross sections when exposure light necessary for removing the resist film is irradiated. Tables 1 and 2 show the relationship between the intensity of the exposure light (the intensity of the exposure light necessary for removing the resist film) with respect to the transmittance of the semitransparent film of the semitransparent portion with respect to each pitch width. Table 1 shows the case where the bias portion is 0.5 mu m (Example 1), and Table 2 shows the case where the bias portion is 0.8 mu m (Example 2).

7 to 12, Table 1, and Table 2 show that, along with increasing the transmittance of the translucent film of the translucent portion forming the line pattern, the resist film of the exposed portion is removed and the intensity of exposure light necessary for obtaining the required line width Can be reduced. In addition, as the pitch width of the line-and-space pattern becomes smaller, the intensity of the exposure light required to form the resist pattern increases, but compared with the case where the line pattern is formed by the light-shielding film, exposure in the photolithography process It was confirmed that the intensity of light can be greatly reduced.

Claims (17)

A photomask for transferring a predetermined transfer pattern to a resist film formed on an object to be etched and forming the resist film into a resist pattern to be a mask in the etching process,
Wherein the transfer pattern includes a line-and-space pattern formed by patterning a semitransparent film formed on a transparent substrate and comprising a transparent portion and a semi-transparent portion,
The semi-light-transmitting film has a transmittance of 1% or more and 15% or less with respect to the exposure light when the transmittance of the light-transmitting portion with respect to the exposure light is 100%
The semi-light-transmitting film is formed so as to have a film thickness in which the phase difference between the translucent portion and the transparent portion with respect to i-line, h-line and g-line light is 90 degrees or less,
Wherein the line-and-space pattern has a pitch width of 2.0 mu m or more and less than 6.0 mu m, a line pattern is formed by the translucent portion, and the space pattern is formed by the transparent portion. delete The method according to claim 1,
Wherein the photomask is used for exposure using exposing light including i-line, h-line and g-line. The method according to claim 1 or 3,
The line width of the line and space pattern formed on the transparent substrate is LM, the space width is SM, the line width of the line and space pattern formed on the workpiece after etching is LP, and the space width is SP , LM > LP and SM < SP. 5. The method of claim 4,
When the line width LP and the space width SP of the line and space pattern formed on the workpiece are equal, the line width LM and the space width SM of the line and space pattern formed on the transparent substrate satisfy the relation of LM > SM Photomask to meet. 6. The method of claim 5,
Wherein the bias value is 0.2 占 퐉 to 1.0 占 퐉, wherein a half of the difference between the line width LM and the space width SM of the line-and-space pattern formed on the transparent substrate is a bias value. The method according to claim 1 or 3,
Wherein the transfer pattern is a pattern for manufacturing a display device. 8. The method of claim 7,
Wherein the transfer pattern is a pattern for manufacturing a pixel electrode. A step of forming a resist film on the workpiece,
Irradiating the resist film with exposure light through a photomask, developing the resist film to form a resist pattern,
A step of forming at least a part of the workpiece in a line and space pattern by etching the workpiece using the resist pattern as a mask
/ RTI &gt;
A manufacturing method of a display device using the photomask according to any one of claims 1 to 3 as the photomask. 10. The method of claim 9,
The line width LP of the line and space pattern formed in the workpiece after the etching process is made smaller than the LM and the space width is set smaller than the LM when the line width of the line and space pattern of the photomask is LM and the space width is SM, Wherein SP is larger than SM. 11. The method of claim 10,
The line width LM of the line and space pattern of the photomask is made larger than the space width SM in the case where the line width LP and the space width SP of the line and space pattern formed in the workpiece are formed to have the same width Gt; 12. The method of claim 11,
Wherein the wet etching is performed as the etching. 13. The method of claim 12,
Wherein the resist film has a wet etching rate of 10 times or more the etching selectivity with respect to the workpiece. 10. The method of claim 9,
Wherein a small irradiation amount is used in comparison with an exposure light irradiation amount required when the translucent portion is the light shielding portion in the transfer pattern at the time of the exposure light irradiation. A manufacturing method of a pixel electrode for a display device, characterized in that a pixel electrode is formed by etching a transparent conductive film using the manufacturing method of a display device according to claim 9. There is provided a method of manufacturing a photomask in which a predetermined transfer pattern is transferred to a resist film formed on a workpiece to be etched and the resist film is formed into a resist pattern to be a mask in the etching process,
A step of forming a translucent film on a transparent substrate,
And forming the transfer pattern including a line-and-space pattern composed of a transparent portion and a semi-transparent portion by patterning the translucent film,
The semi-light-transmitting film has a transmittance of 1% or more and 15% or less with respect to the exposure light when the transmittance of the light-transmitting portion with respect to the exposure light is 100%
The semi-light-transmitting film is formed so as to have a film thickness in which the phase difference between the translucent portion and the transparent portion with respect to i-line, h-line and g-line light is 90 degrees or less,
Wherein the line and space pattern has a pitch width of 2.0 mu m or more and less than 6.0 mu m and a line pattern is formed by the translucent portion and a space pattern is formed by the transparent portion. There is provided a pattern transfer method using a photomask for transferring a predetermined transfer pattern to a resist film formed on an object to be etched and forming the resist film as a resist pattern to be a mask in the etching process,
Wherein the transfer pattern includes a line-and-space pattern formed by patterning a semitransparent film formed on a transparent substrate and comprising a transparent portion and a semi-transparent portion,
The semi-light-transmitting film has a transmittance of 1% or more and 15% or less with respect to the exposure light when the transmittance of the light-transmitting portion with respect to the exposure light is 100%
The semi-light-transmitting film is formed so as to have a film thickness in which the phase difference between the translucent portion and the transparent portion with respect to i-line, h-line and g-line light is 90 degrees or less,
A step of preparing a photomask having a pitch width of not less than 2.0 占 퐉 and not more than 6.0 占 퐉 and having a line pattern formed by the translucent portion and a space pattern formed by the transparent portion;
Wherein the photomask is exposed using exposure light including i-line, h-line and g-line.

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