KR101127355B1 - Photomask and method thereof, and pattern transfer method - Google Patents

Abstract

The present invention provides a photomask having a transmissive portion and a translucent portion formed by patterning a semitransmissive film formed on a transparent substrate, and having a line width of less than 3 μm on a transfer object by exposure light having passed through the photomask. In a photomask for forming a transfer pattern, the photomask includes a pattern comprising a light transmitting portion and a semi-transmissive portion, wherein at least one of the light transmitting portion or the semi-transmissive portion has a portion having a line width of less than 3 μm.

Photomask, Pattern Transfer, Transparent Substrate, Thin Film Transistor, Liquid Crystal Display

Description

Photomask, its manufacturing method, and pattern transfer method {PHOTOMASK AND METHOD THEREOF, AND PATTERN TRANSFER METHOD}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to photomasks used for the manufacture of liquid crystal displays (hereinafter referred to as "LCDs"), and particularly preferably for the manufacture of thin film transistor substrates used for the manufacture of thin film transistor liquid crystal displays. It relates to a large-scale photomask (for example, 300 mm or more on one side), a manufacturing method thereof, and a pattern transfer method using the photomask.

Currently, in the field of LCD, a thin film transistor (Thin Film Transistor Liquid Crystal Display: hereinafter referred to as 'TFT') with a thin film transistor (hereinafter referred to as 'TFT'), CRT ( Compared with the cathode ray tube), commercialization is rapidly progressing because of the advantages of being thin and having low power consumption. The TFT-LCD includes a TFT substrate having a structure in which TFTs are arranged in each pixel arranged in a matrix form, and a color filter in which red, green, and blue pixel patterns are arranged in correspondence with each pixel under the interposition of the liquid crystal layer. It has a schematic structure. TFT-LCD has many manufacturing processes, and was produced using only 5-6 photomasks only by TFT board | substrate. Under these circumstances, a method of manufacturing a TFT substrate using four photomasks has been proposed.

This method is to reduce the number of masks used by using a photomask (hereinafter referred to as a "gray tone mask") having a light shielding portion, a light transmitting portion, and a semi-transmissive portion (gray tone portion). Here, the semi-transmissive portion refers to a portion for controlling the amount of remaining film after development of the photoresist film on the transfer object by reducing a predetermined amount of the transmissive exposure light when the pattern is transferred to the transfer body using a mask. The photomask which has such a translucent part with a light shielding part and a light transmitting part is called a gray tone mask.

3 and 4 show an example of a manufacturing process of a TFT substrate using a gray tone mask. 4 shows a manufacturing process following the manufacturing process of FIG. 3.

On the glass substrate 1, the metal film for gate electrodes is formed, and the gate electrode 2 is formed by the photolithography process using a photomask. Thereafter, the gate insulating film 3, the first semiconductor film 4 (a-Si: amorphous silicon), the second semiconductor film 5 (N + a-Si), the metal film 6 for the source / drain and A positive photoresist film 7 is formed (FIG. 3A). Next, the positive photoresist film 7 is exposed and developed by using the gray tone mask 10 having the light shielding portion 11, the light transmitting portion 12, and the semi-transmissive portion 13. As a result, the first resist pattern 7a is formed so as to cover the TFT channel portion forming region and the source / drain forming region, the data line forming region, and to make the channel portion forming region thinner than the source / drain forming region (Fig. (B)) of 3; Next, using the first resist pattern 7a as a mask, the source / drain metal film 6 and the second and first semiconductor films 5 and 4 are etched (FIG. 3C). Next, the thin resist film in the channel portion forming region is removed by ashing with oxygen to form the second resist pattern 7b (Fig. 4 (a)). Thereafter, the source / drain metal film 6 is etched using the second resist pattern 7b as a mask to form the source / drain 6a, 6b, and then the second semiconductor film 5 is etched. (B) of FIG. 4, and finally, the remaining second resist pattern 7b is peeled off (FIG. 4c).

As the gray tone mask 10 used here, the thing of the structure in which the semi-transmissive part is formed in a fine pattern is known. For example, as shown in FIG. 5, the gray tone mask includes light blocking portions 11a and 11b corresponding to the source / drain, a light transmitting portion 12, and a semi-light transmitting portion corresponding to the TFT channel portion (gray tone portion; 13). The transflective part 13 is an area | region in which the light shielding pattern 13a which consists of a fine pattern below the resolution limit of the LCD exposure machine which uses the gray tone mask 10 is formed. Usually, the light shielding portions 11a and 11b and the light shielding pattern 13a are both formed of a film having the same thickness made of the same material such as chromium or a chromium compound. In most cases, the resolution limit of the LCD exposure machine using a gray tone mask is about 3 m with a stepper type exposure machine and about 4 m with a mirror projection type exposure machine. For this reason, for example, in FIG. 5, the space width of the transmissive part 13b in the translucent part 13 may be less than 3 micrometers, and the line width of the light shielding pattern 13a may be less than 3 micrometers below the resolution limit of an exposure machine. have.

The semi-transmissive portion of the above-described fine pattern type may be a line-and-space type or dot (dotted dot) type fine pattern for designing the gray tone portion, specifically, the halftone effect between the light shielding portion and the light transmitting portion. There is a choice of whether to use, or any other pattern. For example, when designing a fine pattern by line and space, it is possible to control the total transmittance by appropriately selecting the line width, the area ratio between the light transmitting portion and the light blocking portion.

On the other hand, the method of realizing the said semi-transmissive part using the semi-transmissive film of semi-transmissive (for example, 40-60% of exposure light etc.) is known (for example, patent document 1: Unexamined-Japanese-Patent No. 2002-189280). By using this semi-transmissive film, halftone exposure can be performed by reducing the exposure amount of a semi-transmissive part. In the case of using a semi-transmissive membrane, it is sufficient to design only how much the total transmittance is necessary in the design, and there is an advantage that the gray tone mask can be produced only by selecting the film type (film material) or the thickness of the translucent membrane. . Therefore, in manufacture of a gray tone mask, it is enough only to control the film thickness of a translucent film, and it is comparatively easy to manage. In addition, in the case where the TFT channel portion is formed by the semi-transmissive portion of the gray tone mask, the semi-transmissive film can be easily patterned by a photolithography process, and therefore, there is an advantage that the shape of the TFT channel portion can be a complicated pattern.

A display device, especially the photomask for liquid crystal display device manufacture, is based on the assumption that it is used by the exposure machine of the resolution according to the dimension of the pattern of the liquid crystal display device, achieves the appropriate dimensional precision there, and defect inspection etc. are performed. Here, in the method for realizing the semi-transmissive portion using the above-described fine pattern, the fine pattern of the semi-transmissive portion is designed using the resolution limit of the exposure machine, and the resist on the transfer object is designed according to the amount of exposure light of this portion. The remaining film amount of the film is reduced by a desired amount, and as a result, the number of masks to be used is reduced.

That is, under the exposure conditions of an exposure machine which is usually used, it is assumed that the resolution limit is about 3 µm, and if necessary, the exposure conditions are adjusted to make the unresolution transfer image more uniform. It is also possible, but even so, the resolution limit of such an exposure machine is used. Conventionally, in this field, there is a background that a resolution of this level is sufficient even as a display device for transferring a predetermined pattern using a photomask to manufacture it.

By the way, in recent years, it is required to transfer a more precise pattern. For example, the possibility of increasing the operation speed of a thin film transistor is examined by making the dimension of a channel part small more than before.

However, in order to increase the resolution according to the exposure conditions, changing the light source of the exposure machine (that is, making the wavelength region of the light source to the short wavelength side) is not only a large change in equipment but also conditions such as spectral sensitivity of the photoresist. You need to change it. In fact, in the exposure apparatus for manufacturing a liquid crystal display device in which it is usually necessary to use a light source in a wavelength region of about 365 to 436 nm in order to obtain a large amount of light for realizing a large-area exposure, the light source in the short wavelength region as described above. It is not applicable to increase the resolution by using A, and as long as it depends on the exposure light source, it is difficult to achieve both the resolution of the exposure machine and the large amount of light. In addition, there is a cost-related obstacle in terms of increasing the resolution only by designing the optical system of the exposure machine (for example, applying a high NA (opening number) optical system).

This invention is made | formed in view of the said conventional problem, and resolves the pattern of several micrometers or less, for example, 3 micrometers or less which could not be resolved under the exposure conditions of the exposure machine conventionally used for liquid crystal display device manufacture, and is more precise. It is a first object to provide a photomask for obtaining a transfer image.

Moreover, this invention makes it a 2nd object to provide the preferable manufacturing method of such a photomask.

Another object of the present invention is to provide a precise pattern transfer method using the photomask.

In order to solve the said subject, this invention has the following structures.

<Configuration 1>

A photomask having a transmissive portion and a semi-transmissive portion formed by patterning a semi-transmissive film formed on a transparent substrate, wherein a transfer pattern having a line width of less than 3 μm is formed on the transfer object by exposure light transmitted through the photomask. In the photomask to be formed, at least one of the light transmitting portion or the semi-transmissive portion includes a pattern comprising the light transmitting portion and the semi-transmissive portion having a line width portion of less than 3 μm.

<Configuration 2>

The said pattern is a photomask as described in the structure 1 characterized by the line width of the said light-transmitting part having a part less than 3 micrometers.

<Configuration 3>

When the exposure light transmittance of the said transparent substrate is 100%, the exposure light transmittance of the said semi-transmissive film is the range of 20%-60%, It is a photomask as described in the structure 1 or 2 characterized by the above-mentioned.

<Configuration 4>

The wavelength region of the said exposure light contains the wavelength region within the range of 365 nm-436 nm, The photomask in any one of the structures 1-3 characterized by the above-mentioned.

<Configuration 5>

The said transflective part is the photomask in any one of the structures 1-4 characterized by the phase difference of the said exposure light with respect to the said transmissive part being 60 degrees or less.

<Configuration 6>

Said photomask is a photomask for liquid crystal display device manufacture, The photomask in any one of the structures 1-4 characterized by the above-mentioned.

<Configuration 7>

A photomask having a transmissive portion and a semi-transmissive portion formed by patterning a semi-transmissive film formed on a transparent substrate, wherein a transfer pattern having a line width of less than 3 μm is formed on the transfer object by exposure light transmitted through the photomask. A method of manufacturing a photomask to be formed, comprising a pattern comprising a line width portion of less than 3 μm on at least one of the light transmissive portion and the transflective portion, wherein the pattern comprising the light transmissive portion and the translucent portion is formed. It is a manufacturing method.

<Configuration 8>

Under predetermined exposure conditions, the correlation between the line width of the transmissive portion or semi-transmissive portion having a line width portion of less than 3 μm on the photomask and the line width of the resist pattern formed on the corresponding transfer member is determined in advance, and the correlation Based on the relationship, the line width of the light transmitting portion or the semi-transmissive portion formed in the photomask is determined, and a pattern comprising the light transmitting portion and the semi-transmissive portion is formed on the photomask based on the determined line width dimension. It is a manufacturing method of the photomask of the structure 7.

<Configuration 9>

It exposes to a to-be-transferred body by exposure light of the wavelength range of 365nm-436nm using the photomask in any one of the structures 1-5, or the photomask by the manufacturing method of the structures 7 or 8. The pattern transfer method is characterized by transferring a pattern having a line width of less than 3 µm.

According to the photomask of this invention, when a predetermined pattern is transferred to a to-be-transferred body using the photomask in the manufacturing process of a liquid crystal manufacturing apparatus, for example, it is less than 3 micrometers. It is possible to form a fine pattern of line width. And according to the pattern transfer method using the photomask of this invention, when forming such a precision pattern on a to-be-transferred body, it is necessary to change the optical system and light source wavelength range of the conventional exposure machine conventionally used for manufacture of a liquid crystal display device. The present invention can be used as it is, without increasing the actual resolution. Therefore, according to this invention, manufacture of the liquid crystal display device which has a precision pattern more than before can be performed simply.

EMBODIMENT OF THE INVENTION Hereinafter, the best form for implementing this invention is demonstrated.

The present invention is a photomask having a transmissive portion and a semi-transmissive portion formed by patterning a semi-transmissive film formed on a transparent substrate as described in the above Structure 1, wherein the exposure mask has passed through the photomask. Thereby, in the photomask which forms a transfer pattern of less than 3 micrometers in width | variety on a to-be-transmitted body, the pattern which consists of the said light-transmitting part and the said semi-transmissive part in which at least one of the said translucent part or the said translucent part has a line width part less than 3 micrometers It relates to a photomask that includes.

That is, the present invention aims at actually transferring a fine pattern of less than 3 µm onto a transfer object, and provides a structure of a photomask used therefor.

In the photomask of the present invention, at least one of the light transmitting portion or the semi-transmissive portion has a line width portion of less than 3 μm, and even when the light transmitting portion or the semi-transmissive portion has a line width portion of 2 μm or less, a fine pattern is formed on the transfer object. It is possible to transfer, and the effect of the present invention is remarkable.

For example, the line-and-space pattern of the line width A micrometer (for example, 2 micrometers) of a line part (translucent film formation part), and the line width A micrometer (for example, 2 micrometers) of a space part (exposed transparent substrate) When formed on the photomask and transferred to the positive resist on the transfer object, a line pattern having a line width of less than A μm (for example, 1.8 μm) can be formed on the transfer body as a resist pattern. In this case, the line width of the space becomes a value exceeding A µm.

Also in the case of the line width B mu m (B≤A) of the line portion and the line width A mu m of the space portion, the same pattern can be formed on the transfer object.

In addition, when a line-and-space pattern having a line width C mu m (C> A) of the line portion and a line width A mu m of the space portion is formed on the photomask, and transferred to a positive resist on the transfer member, a space having a line width of less than A mu m A pattern can be formed on a to-be-transferred body. In this case, the line width of the line portion exceeds C µm.

In addition, in the above, when any one of a line part or a space part is made into less than 3 micrometers in line width, the remarkable effect of this invention is acquired.

Of course, it is also possible to use not only positive resist but also negative resist for a to-be-transferred body. In that case, by using a photomask in which the light-transmitting portion (the portion exposed by the transparent substrate) is replaced with the light-shielding portion (using a film whose transmittance is substantially zero) in the photomask, a desired transfer pattern is obtained in the same manner as described above. It can form on a to-be-transferred body.

According to the present invention, as described above, by appropriately selecting the line width of the light transmitting portion or the semi-light transmitting portion in the photomask, a pattern having a line width of 1.5 μm or less can be formed on the transfer object.

In the photomask of this invention, the line | wire width part of less than 3 micrometers may exist in a translucent part, or may exist in a transflective part, and may be in both a translucent part and a translucent part. In the present invention, a pattern having a line width portion of less than 3 μm in the light transmitting portion or the semi-transmissive portion is, for example, a line-and-space formed by a line portion (semi-transmissive portion) and a space portion (transmissive portion) used in Examples described later. Although it can be set as a pattern, of course in this invention, it is not limited to this, For example, it can be set as the arbitrary pattern shape according to the pattern of a liquid crystal display device.

It is preferable that the photomask which concerns on this invention especially contains the pattern in which the transmissive part of less than 3 micrometers of line widths fitted in the translucent part is formed. The photomask containing such a pattern can be used suitably as a photomask for channel part formation of a TFT substrate in a liquid crystal display device, for example.

As said semi-transmissive film in the photomask of this invention, when making the exposure light transmittance of a transparent substrate (transmission part) into 100%, the transmittance | permeability with respect to the exposure light of a semi-transmissive film is 20-60% of range, for example. Can be applied. More preferably, it is in 40 to 60% of range. As the material of the semi-transmissive film, a known one can be used arbitrarily as the above-mentioned exposure light transmittance can be obtained. W, Al, etc. can be used. In particular, molybdenum silicide compounds are preferred. This is because the film thickness for obtaining the above transmittance can be made small, the aspect ratio of the pattern can be made small, and it is relatively easy to maintain the pattern precision. Moreover, when using the said translucent film with the light shielding film by Cr or Cr compound, since Cr or Cr compound has etching selectivity, processing precision can be made high.

As a film thickness of the said semi-transmissive film, in order to obtain the said transmittance, it can be 100-600 Pa (angstrom) in the case of chromium oxide (CrO), and 30 Pa-120 Pa in the case of MoSi compound. Moreover, it is preferable that the phase difference with respect to the exposure light which permeate | transmits the said translucent part of the exposure light which permeate | transmits the said semi-transmissive part becomes 60 degrees or less in the said semi-transmissive film. More preferably, it is 5-40 degrees.

By using the photomask of this invention, as shown in the below-mentioned Example, it is possible to form a pattern with a dimension substantially smaller than 3 micrometers as a transfer image pattern.

In the exposure process using the photomask of this invention, a well-known large size mask exposure machine (aligner) can be used. As a light source wavelength, the thing of the wavelength range of i line | wire-g line | wire can be used. In addition, it is also possible to select the wavelength region of the light source wavelength or to adjust the optical system (aperture NA, etc.) by the line width of the fine pattern of the present invention. That is, when the line width of a fine pattern is small, when the intensity | strength of i line side (short wavelength side) is high, when the numerical aperture NA of an optical system is large, it is easy to resolve more.

The photomask of this invention can have a pattern or area | region other than the fine pattern by the said translucent film on the same board | substrate. The photomask may have a semi-transmissive film portion which does not have a fine pattern, for example. The semi-transmissive film portion not having this fine pattern can control the remaining film thickness value after development of the resist pattern formed on the transfer object by reducing the amount of exposure light transmitted by a predetermined amount as compared with the transparent substrate portion (transmission portion). The material of the translucent film used in this case is simple in manufacturing, and it is advantageous to make it the same as the translucent film which has the said fine pattern. Moreover, you may have a light shielding film pattern which has a fine pattern with a line width of less than 3 micrometers, for example on the same board | substrate. In the light shielding film pattern having such a fine pattern, under the exposure conditions by a normal exposure apparatus for a liquid crystal display device, the amount of exposure light is reduced by a predetermined amount as compared with the transparent substrate portion, and the remaining film after development of the resist pattern formed on the transfer member The thickness value can be controlled. That is, in the optical conditions in which the fine pattern of the translucent film resolves, the fine pattern formed by the light shielding film may not be resolved.

Moreover, you may have the light shielding film pattern which does not have a fine pattern on the same board | substrate. As described above, when a photomask having a plurality of types of patterns including a fine pattern by a semi-transmissive film is used for exposure to a transfer member having a photoresist film, a resist step due to a plurality of resist residual film thickness values can be formed. It can be used as a so-called multi-tone mask.

For example, as illustrated in FIG. 1A, the photomask 20 according to the present invention includes the light shielding portion 24 formed by the light shielding film 22 having no fine pattern on the transparent substrate 21. It consists of the semi-transmissive part 25 by the semi-transmissive film 23 which does not have a fine pattern, and the fine pattern part 26 (the translucent part by the transmissive part and the translucent film 23) by the translucent film 23 ), Four or more regions of the light-transmitting portion 27 (the transparent substrate 21 is exposed) can be formed.

The present invention also provides a method for producing the photomask. That is, the manufacturing method of the photomask which concerns on this invention is a photomask which has a transmissive part and a semi-transmissive part which formed the predetermined pattern by patterning the semi-transmissive film formed on the transparent substrate, The exposure mask which permeate | transmitted the photomask is provided. A method of producing a photomask in which a transfer pattern having a line width of less than 3 μm is formed on a transfer object, wherein the light transmitting portion and the half include a line width portion of less than 3 μm in at least one of the light transmitting portion and the semi-transmissive portion. It is obtained by forming the pattern which consists of a light transmission part.

As described above, according to the photomask obtained by the manufacturing method, it is possible to actually transfer a fine pattern having a dimension of less than 3 μm on the transfer target, and also to form a pattern having a line width of 2 μm or less on the transfer target. It is possible.

Here, for example, in the case of the photomask of this invention which has a translucent film and a light shielding film on a transparent substrate, it can obtain by the following processes.

(1) A photomask blank in which a semitransmissive film and a light shielding film are laminated in this order on a transparent substrate is prepared, and a resist pattern of a region corresponding to the light shielding portion and the semitransmissive portion is formed on the photomask blank. Using this as a mask, the exposed light shielding film is etched. Using the resist pattern or the light shielding film pattern formed by using the resist pattern as a mask, the light-transmitting portion is formed by etching the exposed semi-transmissive film. Then, a resist pattern is formed in a region including at least a portion to be a light shielding portion, and the exposed light shielding film is etched using the resist pattern as a mask to form a translucent portion and a light shielding portion. In this way, the photomask in which the semi-transmissive part by the semi-transmissive film containing a fine pattern, the light-shielding part by the laminated film of a light-shielding film and a semi-transmissive film, and a light-transmitting part was formed on the transparent substrate, respectively.

In addition, in order to form a fine pattern in a semi-transmissive part, in a 1st resist patterning process, the fine pattern of less than 3 micrometers is drawn in a semi-transmissive part in the said process.

(2) Preparing a photomask blank having a light shielding film formed on a transparent substrate, forming a resist pattern of a region corresponding to the light shielding portion on the photomask blank, and etching the exposed light shielding film using the resist pattern as a mask. Form a pattern. Next, after removing the resist pattern, a translucent film is formed on the entire surface. Then, a resist pattern is formed in regions corresponding to the light shielding portion and the semi-transmissive portion, and the light-transmissive portion and the semi-transmissive portion are formed by etching the exposed semi-transmissive film using the resist pattern as a mask. In this way, the photomask in which the semi-transmissive part by the semi-transmissive film containing a fine pattern, the light-shielding part by the laminated film of a light-shielding film and a semi-transmissive film, and a light-transmitting part was formed on the transparent substrate, respectively.

In addition, in order to form a fine pattern in a transflective part, in a 2nd resist patterning process, the micropattern of less than 3 micrometers is drawn in a semi-transmissive part in the said process.

(3) Furthermore, a resist pattern of a region corresponding to the light shielding portion and the light transmitting portion is formed on the same photomask blank as in (2) above, and the exposed light shielding film is etched using the resist pattern as a mask to thereby form the semi-transmissive portion. The transparent substrate in the corresponding area is exposed. Next, after removing the resist pattern, a semi-transmissive film is formed on the entire surface, and a resist pattern is formed in a region corresponding to the light shielding portion and the semi-transmissive portion, and the exposed semi-transmissive film (and semi-transmissive) is used as the resist pattern as a mask. Film and light shielding film) are etched. In this way, the light transmissive portion and the light transmissive portion and the semi-transmissive portion including the fine pattern may be formed on the transparent substrate, respectively.

Also in this case, in order to form a fine pattern in a semi-transmissive part, in a 2nd resist patterning process, the fine pattern of less than 3 micrometers is drawn in the semi-transmissive part.

Of course, the manufacturing process of the photomask of this invention does not need to be limited to the above-mentioned (1)-(3).

Also, as can be seen by referring to the photographs of Figs. 2A and 2B, which show the results of the examples described later, for example, the width of the semi-transmissive portion on the photomask is 2 μm or 10 μm, In the transfer image (resist pattern) when the master pattern including the line and space having a width of 2 μm is used, the line widths of the transfer images and the transflective portions of the translucent portion may not be the same as the mask pattern. Thus, the size of a transfer image may differ depending on a mask pattern shape. Therefore, when designing the mask pattern, it is desirable to consider this element in advance.

For example, the correlation between the line width of the transmissive portion or semi-transmissive portion having a line width portion of less than 3 μm on the photomask under predetermined exposure conditions and the line width of the resist pattern formed on the corresponding transfer member is obtained in advance. Based on the obtained correlation, the line width of the light transmitting portion or the semi-light transmitting portion formed in the photomask is determined. And based on the determined line width dimension, it is preferable to form the mask pattern which consists of a translucent part and a translucent part on a photomask.

The present invention also provides a pattern transfer method using the photomask. That is, using the said photomask, exposure to a to-be-transferred body can be performed by exposure light of the wavelength range of 365 nm-436 nm. Thereby, the pattern which has a line width of less than 3 micrometers can be transferred with sufficient resolution, even under the exposure conditions for the liquid crystal display device of image development. As described above, the intensity distribution in the wavelength region, the NA of the optical system, and the like may be appropriately adjusted.

On the transparent substrate 21 illustrated in FIG. 1A described above, the light shielding portion 24, the semi-transmissive portion 25 having no fine pattern, and the fine pattern portion 26 by the semi-transmissive film 23 are provided. And exposing the photomask 20 according to the present invention having the light transmitting portion 27 to the exposure light 40 and transferring the pattern to the photoresist film (positive type) 33 on the transfer object 30. As shown in FIG. 1B, on the transfer member 30, the remaining film region 33a of the thick film after development, the remaining film region 33b of the thin film, and the fine pattern portion 26 on the photomask are formed. A transfer pattern (resist pattern) consisting of a corresponding fine pattern region 33c and a region 33d substantially free of residual film is formed. 1 (a) and (b), reference numerals 32a and 32b denote films deposited on the substrate 31 in the transfer target body 30.

Conventionally, as a large size photomask for liquid crystal display device manufacture, the line | wire width exceeding 3 micrometers is normally applied as a pattern which resolves by exposure and transfers. This is because the above-described dimensional accuracy can be satisfied with respect to the pitch of the pattern largely determined by the number of pixels of the display device. In addition, in the exposure process using a photomask, since a large area needs to be exposed, a large amount of light is needed for efficient exposure, and although the wavelength of the area | region from i line | wire to g line | wire is normally used, it is a stepper for semiconductor manufacture. Unlike a single wavelength, the resolution is lower than that of a single wavelength, which is also a cause of the limitation of resolution. However, according to the present invention, even when such exposure conditions are applied, a substantial resolution higher than that of the conventional one is obtained, which makes it possible to transfer a more precise pattern.

By the way, when transferring the fine pattern of the translucent film which concerns on this invention by exposure, the transmission amount of exposure light becomes larger than the exposure light transmission amount of the light shielding pattern part by the light shielding film of a general binary mask. For this reason, the resist residual film value on the to-be-transmitted body when transferring the fine pattern part by a translucent film becomes smaller than the resist residual film value when transferring a normal light shielding film pattern (this is the case of positive type photoresist, and it is negative In the case of a type photoresist, the reverse) may occur. In this case, in the developing process of the photoresist after exposure, it is possible to suitably adjust the resist residual film value by appropriately adjusting the conditions, and to perform the etching process of the subsequent transfer object appropriately.

In addition, if the resist film thickness is insufficient for the etching process of the transfer target after transferring the pattern to the transfer target by using the photomask according to the present invention, before applying the photoresist film onto the transfer target beforehand, A material having etching selectivity with the film to be formed (for example, metal or SiO ₂₎ An extremely thin film). It is also possible to employ a method of etching the above extremely thin film using the resist pattern formed in the pattern transfer as a mask and etching the film on the lower layer side using the film as a mask.

[Example]

Hereinafter, the present invention will be described in more detail with reference to Examples.

A synthetic quartz substrate was used as the transparent substrate, and a semi-transmissive film made of a MoSi compound was formed into a film by a sputtering method on the transparent substrate. The semi-transmissive film has a transmittance of 50% (when the transmittance of the exposure light of the transparent substrate is 100%) at g line in the exposure light (wavelength range of 365 nm to 436 nm) of the exposure machine used for pattern transfer described later. The film thickness was set. At this time, the phase difference with respect to the exposure light which permeate | transmitted through the transparent substrate of the exposure light which permeate | transmitted the part which formed the translucent film was less than 60 degree | times. And a positive photoresist was apply | coated on this translucent film, and the photomask blank was prepared.

In this photomask blank, a line-and-space pattern having a width of 2 µm in both the line portion and the space portion was drawn, developed to form a resist pattern, and the semi-transmissive film was etched using the resist pattern as a mask to obtain a photomask. Also in the obtained photomask, the line part (semi-transmissive part) and the space part (transmission part) were formed with the line and space pattern of 2 micrometers in width.

The photograph of the resist pattern on the to-be-transferred body obtained by exposing and developing on the to-be-transferred body on which the positive type photoresist film | membrane was formed using the photomask obtained in this way is shown to FIG. 2 (a). Moreover, the line width in this resist pattern was 1.84 micrometers, and the space width was 2.30 micrometers.

Further, a photomask having a line and space pattern having a width of 10 μm in a line portion and a width of 2 μm in a space portion formed on the transparent substrate is similarly formed with the translucent film, and using the photomask, the exposure machine is formed on the object to be transferred. The photo of the resist pattern on the to-be-transferred body obtained by exposing and developing using is shown to FIG. 2 (b). Moreover, the line width in this resist pattern was 10.38 micrometers, and the space width was 1.56 micrometers.

As apparent from the photographs of FIGS. 2A and 2B, according to the present invention, a pattern having a portion having a line width of less than 3 μm is resolved, and a transfer pattern having a line width of less than 3 μm is formed on a transfer object. It is possible.

Hereinafter, a comparative example with respect to the Example of this invention is demonstrated.

On the same transparent substrate as in the above-mentioned embodiment, a light-shielding film made of Cr was formed by a sputtering method to a predetermined film thickness, and the same positive photoresist as in the above-described embodiment was applied on the light-shielding film to prepare a photomask blank.

In this photomask blank, a line-and-space pattern having a width of 2 μm in both the line portion and the space portion was drawn, developed to form a resist pattern, and the light shielding film was etched using the resist pattern as a mask to obtain a photomask. Also in the obtained photomask, the line-and-space pattern in which both the line part (light shielding part) and the space part (light transmitting part) was 2 micrometers in width was formed.

The photograph of the resist pattern on the to-be-transferred body obtained by exposing and developing using the exposure machine used in the Example on the to-be-transferred body in which the positive type photoresist film was formed using the photomask obtained in this way is shown in FIG.2 (c). Indicates.

Furthermore, a photomask in which a line and space pattern having a width of 10 μm in a line portion and a width of 2 μm in a space portion is formed on the transparent substrate in the same manner as that of the light shielding film is fabricated. The photograph of the resist pattern on the to-be-transferred body obtained by exposing and developing is shown in FIG.2 (d).

As apparent from the photographs of Figs. 2 (c) and 2 (d), according to this comparative example using a photomask in which a fine pattern was formed with a Cr light shielding film, a pattern having a line width portion of less than 3 μm cannot be resolved. It is not possible to form a transfer pattern having a line width of less than 3 μm on the transfer object.

As mentioned above, although this invention was demonstrated based on preferable embodiment, it cannot be overemphasized that this invention is not limited only to the said embodiment.

1 (a) and 1 (b) are cross-sectional views for explaining a pattern transfer method using a photomask according to the present invention.

2 (a) and 2 (b) are photographs of the resist pattern on the transfer body obtained by the pattern transfer according to the embodiment of the present invention, and FIGS. 2 (c) and 2 (d) show the pattern transfer of the comparative example. The photograph of the resist pattern on the to-be-transferred body obtained.

3 (a) to 3 (c) are schematic cross-sectional views showing a manufacturing process of a TFT substrate using a gray tone mask.

(A)-(c) is a schematic sectional drawing which shows the manufacturing process of the TFT substrate using a gray tone mask following the manufacturing process of FIG. 3 (a)-(c).

5 is a plan view showing an example of a conventional gray pattern mask of a gray tone.

Claims (14)

A photomask having a transmissive portion and a translucent portion, in which a predetermined pattern is formed by patterning a semitransmissive film formed on a transparent substrate, The said semi-transmissive film is a phase difference with respect to the exposure light which permeate | transmits the said translucent part of the exposure light which permeate | transmits the said translucent part becomes 60 degrees or less, The photomask includes a pattern comprising the light transmitting portion and the semi-transmissive portion, wherein at least one of the light transmitting portion or the semi-transmissive portion has a portion having a line width of more than 0 μm and less than 3 μm, The exposure light that has passed through the photomask by exposing the photomask under exposure conditions of an LCD exposure machine using an exposure light including a plurality of wavelengths in a wavelength range of 365 nm to 436 nm and having a resolution limit of 3 µm or more. A photomask for manufacturing a liquid crystal display device, characterized in that a transfer pattern having a line width of more than 0 µm and less than 3 µm is formed on the transfer object. The method of claim 1, The pattern is a photomask for manufacturing a liquid crystal display device, characterized in that the line width of the light transmitting portion has a portion of more than 0 µm and less than 3 µm. The method of claim 1, When the exposure light transmittance of the said transparent substrate is made into 100%, the exposure light transmittance of the said translucent film is 20%-60% of the range, The photomask for liquid crystal display device manufacture. The method of claim 1, The pattern is a line-and-space pattern composed of the light transmitting portion and the semi-transmissive portion, wherein at least one of the light transmitting portion and the semi-transmissive portion has a line width of more than 0 μm and less than 3 μm. Photomasks for Manufacturing. The method of claim 1, The pattern is a line-and-space pattern consisting of the light transmitting portion and the semi-transmissive portion, wherein at least one of the light transmitting portion and the semi-transmissive portion has a line width of more than 0 μm and less than 2 μm. Photomasks for Manufacturing. The method of claim 1, The pattern is a line-and-space pattern consisting of the light transmitting portion and the semi-transmissive portion, wherein both the light transmitting portion and the semi-transmissive portion have a line width of more than 0 μm and less than 3 μm. . The method of claim 1, A photomask for producing a liquid crystal display device, wherein the semi-transmissive film is made of a chromium compound. The method of claim 1, The said semi-transmissive film is a photomask for liquid crystal display device manufacture characterized by the phase difference of the exposure light which permeate | transmits the said translucent part with respect to the exposure light which permeate | transmits the said transparent part. As a photomask for manufacturing a liquid crystal display device having a transmissive portion and a semi-transmissive portion in which a predetermined pattern is formed by patterning a semi-transmissive film formed on a transparent substrate, exposure light including a plurality of wavelengths in a wavelength region of 365 nm to 436 nm is used. And by exposing the photomask under exposure conditions of an LCD exposure machine having a resolution limit of 3 µm or more, the transfer pattern having a line width of more than 0 µm and less than 3 µm on the transfer object by the exposure light that has passed through the photomask. As a method of manufacturing a photomask for manufacturing a liquid crystal display device, On the transparent substrate, a semi-transmissive film having a phase difference of exposure light passing through the translucent portion to exposure light passing through the transmissive portion is 60 degrees or less, A photo-liquid display device for producing a liquid crystal display device, characterized by forming a pattern comprising the light-transmitting portion and the semi-light-transmitting portion including a portion having a line width exceeding 0 µm and less than 3 µm in at least one of the transparent portion or the translucent portion. Method of making a mask. Exposure light containing a plurality of wavelengths in the wavelength region of 365 nm-436 nm using the photomask of any one of Claims 1-8, or the manufacturing method of Claim 9 using the LCD exposure machine. The pattern transfer method, characterized by exposing to a transfer object and transferring a pattern whose line width exceeds 0 micrometer and is less than 3 micrometers. 10. The method of claim 9, A mirror projection type exposure machine is used as said LCD exposure machine, The manufacturing method of the photomask for liquid crystal display device manufacture. The photomask according to any one of claims 1 to 8, wherein a line-and-space pattern having a line width portion of more than 0 탆 and less than 3 탆 is formed on the light transmitting portion and the semi-transmissive portion, In the pattern transfer method which transfers the said line and space pattern to the positive resist on a to-be-transferred body by exposure light containing the some wavelength in the wavelength range of -436 nm, When the line width of the semi-transmissive portion is A 占 퐉 and the line width of the transmissive portion is B 占 퐉, a line pattern of a resist having a line width of less than A 占 퐉 is formed on the transfer object. A photomask for manufacturing a liquid crystal display device having a light transmitting portion and a semi-transmissive portion, in which a predetermined pattern is formed by patterning a semi-transmissive film formed on a transparent substrate, The said semi-transmissive film is a phase difference with respect to the exposure light which permeate | transmits the said translucent part of the exposure light which permeate | transmits the said translucent part becomes 60 degrees or less, The photomask includes a pattern comprising the light transmitting portion and the semi-transmissive portion, wherein at least one of the light transmitting portion or the semi-transmissive portion has a portion having a line width of more than 0 μm and less than 3 μm, The photomask is transmitted by exposing the photomask under exposure conditions of an LCD exposure machine of a mirror projection method using an exposure light including a plurality of wavelengths in a wavelength range of 365 nm to 436 nm and having a resolution limit of 3 µm or more. A photomask for producing a liquid crystal display device, wherein a transfer pattern having a line width of more than 0 µm and less than 3 µm is formed on the transfer object by the exposure light. As a photomask for manufacturing a liquid crystal display device having a transmissive portion and a semi-transmissive portion in which a predetermined pattern is formed by patterning a semi-transmissive film formed on a transparent substrate, exposure light including a plurality of wavelengths in a wavelength region of 365 nm to 436 nm is used. And by exposing the photomask under the exposure conditions of the LCD projection machine of the mirror projection method having a resolution limit of 3 µm or more, the line width exceeds 0 µm on the transfer object by the exposure light that has passed through the photomask. A manufacturing method of a photomask for manufacturing a liquid crystal display device, in which a transfer pattern of less than [mu] m is formed, On the transparent substrate, a semi-transmissive film having a phase difference of exposure light passing through the translucent portion to exposure light passing through the transmissive portion is 60 degrees or less, A photomask for manufacturing a liquid crystal display device, comprising: forming at least one of the transmissive portion and the translucent portion, the pattern comprising the transmissive portion and the translucent portion, including a portion having a line width exceeding 0 μm and less than 3 μm. Method of preparation.

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