KR20150102004A - Phase Shift Mask and Method For Producing Same - Google Patents

Abstract

A method of manufacturing a phase shift mask includes a step of sputtering a target of a chromium-based material under an atmosphere of a mixed gas containing 10.4% or less oxidizing gas.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a phase shift mask,

The present invention relates to a phase shift mask capable of forming a fine and highly precise exposure pattern and a method of manufacturing the same, and more particularly to a technique which is very suitable for use in the production of a flat panel display (FPD).

The present application claims priority based on Japanese Patent Application No. 2012-285846 filed in Japan on December 27, 2012 and its contents are hereby incorporated herein by reference.

BACKGROUND ART [0002] In a manufacturing process of a semiconductor device or a flat panel display (FPD), a phase shift mask is used for exposing and transferring a fine pattern to a resist film formed on a substrate made of silicon or glass.

In the FPD, by increasing the precision of patterning, the line width size is made finer and the quality of the image is greatly improved. When the line width precision of the photomask and the line width precision of the substrate on the transfer side become finer, the gap between the photomask and the substrate becomes smaller at the time of exposure. Since the glass substrate used for the flat panel has a large size exceeding 300 mm, the glass substrate has a large waviness or surface roughness, which is liable to be influenced by the depth of focus.

Due to the large size of the glass substrate, the exposure of the FPD was performed using a composite wavelength of g-line (436 nm), h-line (405 nm), and i-line (365 nm) ) Exposure method is used (see, for example, Patent Document 1).

On the other hand, in the semiconductor, patterning is performed with a single wavelength of ArF (193 nm), and a halftone phase shift mask is used as a method for achieving further miniaturization (see, for example, Patent Document 2). According to this method, by setting the phase to 180 degrees at 193 nm, it is possible to set the portion where the light intensity becomes zero and improve the patterning accuracy. In addition, since there is a portion where the light intensity is zero, it is possible to set the depth of focus to a large value, so that the exposure condition can be relaxed or the patterning yield can be improved.

<Prior Art Literature>

<Patent Literature>

[Patent Document 1] Japanese Unexamined Patent Application Publication No. 2007-271720 (paragraph [0031])

[Patent Document 2] Japanese Unexamined Patent Application Publication No. 2006-78953 (paragraphs [0002], [0005])

With the recent miniaturization of the wiring pattern of the FPD, a fine line width precision is also required for a photomask used for manufacturing the FPD. However, it is very difficult to cope with only the exposure condition and development condition for the miniaturization of the photomask, and a new technique for achieving new miniaturization has been demanded.

Particularly, when the composite wavelength of g-line, h-line, and i-line is used as described above, the transmissivity of the mask to each wavelength is different. Therefore, when exposure processing is performed on a large area such as FPD, Defects due to light shielding or phase shift occur in the patterning, resulting in a problem that it can not cope with high precision.

Further, in the case of carrying out processing corresponding to a high precision and corresponding to a specific wavelength in order to cope with high precision, light of other wavelength region can not be efficiently used, and the processing efficiency is lowered and manufacturing cost is increased.

An embodiment according to the present invention is to solve the above problems, and it is an object of the present invention to provide a phase shift mask capable of efficiently forming fine and highly precise exposure patterns with respect to a large area such as FPD manufacturing, and a manufacturing method thereof.

(1) A method of manufacturing a phase shift mask according to an embodiment of the present invention includes the steps of: forming a light-shielding layer containing Cr patterned on a transparent substrate as a main component; The target of the chromium-based material is sputtered in an atmosphere of a mixed gas containing an inert gas, a nitriding gas, and an oxidizing gas, so as to have a phase difference of about 180 degrees with respect to the i line, Of not more than 10.4%, and making the difference between the g-line transmittance and the i-line transmittance not more than 5%, and patterning the phase shift layer.

(2) A phase shift mask according to one embodiment of the present invention includes: a light-shielding layer mainly composed of Cr formed on a transparent substrate; And a phase shift layer containing Cr as a main component and having a phase difference of about 180 deg. With respect to the i-line and capable of making the difference between the g-line transmittance and the i-line transmittance 5% or less.

(3) In the embodiment (2), the phase shift mask may be formed such that the light shielding layer is formed on the surface of the transparent substrate, the phase shift layer is formed on the light shielding layer, Wherein the phase shift layer is formed on the phase shift layer and the etching stopper layer is formed on the phase shift layer and includes at least one kind of metal selected from the group consisting of Ni, Co, Fe, Ti, Si, Al, Nb, Mo, Layer, and the light-shielding layer may be formed on the etching stopper layer.

According to the embodiment (1), a step of forming a light shielding layer mainly composed of Cr patterned on a transparent substrate; The target of the chromium-based material is sputtered in an atmosphere of a mixed gas containing an inert gas, a nitriding gas, and an oxidizing gas, so as to have a phase difference of about 180 degrees with respect to the i line, And a step of forming and patterning a phase shift layer having Cr as a main component capable of reducing the difference between the g-line transmittance and the i-line transmittance to 5% or less, It is possible to provide a phase shift mask blank and a manufacturing method capable of manufacturing a phase shift mask which are almost the same as the transmittance for one light in the complex wavelength region.

The phase shift mask blank is a phase shift mask blank for a photomask used for exposure processing by a composite wavelength including a g line (436 nm), an h line (405 nm), and an i line (365 nm) .

According to the embodiment (2), a light-shielding layer mainly composed of Cr formed on a transparent substrate; And a phase shift layer containing Cr as a main component capable of having a retardation of about 180 DEG with respect to the i-line and capable of reducing the difference between the g-line transmittance and the i-line transmittance to 5% or less, It is possible to perform a high-precision exposure treatment on an object to be processed having a large area, and the manufacturing cost can be reduced.

In the case of (3) above, the phase shift mask may be formed such that the light shielding layer is formed on the surface of the transparent substrate, the phase shift layer is formed on the light shielding layer, And an etching stopper layer composed mainly of at least one metal selected from the group consisting of Ni, Co, Fe, Ti, Si, Al, Nb, Mo, W and Hf is formed on the phase- And a phase shift mask blank in which the light shielding layer is formed on the etching stopper layer.

According to the embodiment of the present invention, it is possible to manufacture a phase shift mask blank in which the difference in transmittance by wavelength is reduced, so that the inconvenience of exposure processing is minimized even for an object having a large area such as an FPD, A production method of a phase shift mask capable of producing water at a high yield, a phase shift mask blank and a manufacturing method thereof.

1 is a process diagram illustrating a method of manufacturing a phase shift mask according to a first embodiment of the present invention;
2 is a graph showing the relationship between the transmittance of the phase shift layer of the phase shift mask and the wavelength of transmitted light;
3 is an experimental result showing the relationship between deposition conditions and optical characteristics of the phase-shift layer of the phase shift mask;
4 is a process diagram for explaining the method of manufacturing the phase shift mask according to the second embodiment of the present invention.

In the manufacturing method of the present invention, it may include a step of patterning the light shielding layer on the transparent substrate. A phase shift layer is formed on the transparent substrate so as to cover the light shielding layer. Wherein the phase shift layer is formed of a nitriding gas containing at least 40% and at most 70% of nitriding gas and at least 9.2% of a nitriding gas containing at least 40% and at most 90% nitriding gas and at most 10.4% Or more and 10.4% or less, of an oxidizing gas. The chromium-based material is formed by sputtering a target of a chromium-based material. The phase shift layer has a phase difference of 180 degrees with respect to light according to a complex wavelength including one light, g line (436 nm), h line (405 nm) and i line (365 nm) in a wavelength range of 300 nm to 500 nm And a thickness capable of making the difference between the g-line transmittance, the h-line transmittance, and the i-line transmittance all 5% or less. The formed phase shift layer is patterned into a predetermined shape.

The phase shift mask of the present invention is characterized in that all of the difference between the transmittance of the g line, the transmittance of the h line, and the transmittance of the i line is 5% or less and the phase shift layer . Therefore, according to the phase shift mask, a composite wavelength including the light in the wavelength region, particularly, the g-line (436 nm), the h-line (405 nm), and the i-line (365 nm) A region in which the light intensity is minimized by the inversion action is formed, and the exposure pattern can be made clearer. This phase shift effect greatly improves the pattern accuracy and enables fine and high-precision pattern formation. The difference between the transmittance of the g line and the transmittance of the i line is more preferably not less than 2.5% and not more than 5%. By reducing the difference between the transmittance of the g line and the transmittance of the i line, the transmittance difference at each wavelength becomes small, and the phase shift effect of each wavelength becomes high.

When the phase-shifting layer is formed of a chromium oxynitride-based material, a sputtering film having a desired transmittance and refractive index can be stably formed by setting the mixed gas atmosphere to 10.4% or less of the oxidizing gas. When the oxidizing gas is 9.2% or more, a desired refractive index can be obtained. Therefore, the transmittance at the g-line, h-line and i-line is increased and the phase shifting effect is enhanced. However, since the oxidizing gas is less than 9.2%, the transmittance value is lowered and the effect is recognized even if the phase shift effect is reduced. The oxidizing gas should be at least 6.5%. If the oxidizing gas is more than 10.4%, the oxygen concentration in the film becomes too high to obtain a desired transmittance and refractive index, and oxidation of the target can not be suppressed, making stable sputtering difficult. On the other hand, if the nitriding gas is less than 40%, the oxidation of the target can not be suppressed and stable sputtering becomes difficult. Further, when the nitriding gas exceeds 70%, it becomes difficult to obtain film characteristics such as desired transmittance and refractive index. By vapor deposition in a mixed gas atmosphere under the above conditions, for example, a phase shift layer having a transmittance of 1 to 20% with respect to the i-line can be obtained. Even if the transmittance of the i-line is less than 1%, the effect of the phase shift layer can be obtained, and it may be 0.5% or more.

The thickness of the phase shift layer may be such that the phase difference layer has a phase difference of about 180 DEG with respect to the i-line. Further, the phase shift layer can be formed to have a thickness capable of having a phase difference of about 180 DEG to the h-line or g-line.

Here, 'about 180 °' means 180 ° or 180 °, for example, 180 ° ± 10 ° or less.

It is preferable that the thickness of the phase shift layer is set so that the difference between the transmittance of the g line, the transmittance of the h line, and the transmittance of the i line is 5% or less and the difference in phase difference given to the i line and the phase difference The thickness can be set so that the difference is 40 DEG or less.

As a result, a constant phase shift effect can be obtained with respect to each wavelength light, and fine and highly precise pattern formation can be ensured.

The mixed gas may further include an inert gas.

From this, stable formation of plasma becomes possible. Further, the concentrations of the nitriding gas and the oxidizing gas can be adjusted to a low level

A method of manufacturing an FPD using the phase shift mask of the present invention includes a step of forming a photoresist layer on a substrate. A phase shift mask is disposed close to the photoresist layer. Wherein the phase shift mask has a phase difference of 180 DEG with respect to one of wavelengths in a wavelength range of 300 nm or more and 500 nm or less and changes the transmittance of the g line, the transmittance of the h line, and the transmittance of the i line to 5% Based phase shifting layer made of a chromium oxynitride-based material. The photoresist layer is formed by combining light of a complex wavelength including g-line (436 nm), h-line (405 nm), and i-line (365 nm) As shown in FIG.

The phase shift mask is characterized in that all of the difference between the transmittance of the g line, the transmittance of the h line and the transmittance of the i line is 5% or less and at the same time, 180 [deg.] To one of the wavelengths of 300 nm to 500 nm And a phase shift layer capable of having a phase difference of? Therefore, according to the above manufacturing method, it is possible to improve the pattern accuracy based on the phase shift effect by using the light in the wavelength region, and it is possible to form a fine and high-precision pattern. As a result, a high-quality flat panel display can be manufactured.

As the light of the composite wavelength, light including g-line (436 nm), h-line (405 nm), and i-line (365 nm) can be used.

The phase shift mask of the present invention includes a transparent substrate, a light shielding layer, and a phase shift layer. The light-shielding layer is formed on the transparent substrate. The phase shift layer is formed around the light-shielding layer so that the difference in transmittance between the g-line, the h-line, and the i-line is all 5% or less and at the same time, Based material capable of providing a phase difference of 180 DEG with respect to the substrate.

According to the phase shift mask, since the pattern precision based on the phase shift effect can be improved by using the light of the complex wavelength, fine and highly precise pattern formation can be achieved. This effect becomes more remarkable by using an exposure technique in which light of different wavelengths (for example, g-line (436 nm), h-line (405 nm), and i-line (365 nm)) are combined in the wavelength range.

The thickness of the phase shift layer is preferably set such that the difference in transmittance between the g line, the h line and the i line is 5% or less, and the difference in phase difference given to the i line and the phase difference given to the g line is 30 The thickness can be made to be.

As a result, a constant phase shift effect can be obtained for each wavelength, and fine and high-precision pattern formation can be ensured.

&Lt; Embodiment 1 >

 Hereinafter, one embodiment of a method of manufacturing a phase shift mask according to the present invention will be described with reference to the drawings.

1 is a process diagram schematically showing a method of manufacturing a phase shift mask according to this embodiment.

The phase shift mask of the present embodiment is configured as a patterning mask for a FPD glass substrate, for example. As described later, a composite wavelength of i-line, h-line, and g-line is used for patterning the glass substrate using the mask.

In the method of manufacturing the phase shift mask according to the present embodiment, first, as shown in Fig. 1 (a), the light shielding layer 11 is formed on the transparent substrate 10.

As the transparent substrate 10, a material excellent in transparency and optical isotropy is used. For example, a quartz glass substrate is used. The size of the transparent substrate 10 is not particularly limited, and is appropriately selected in accordance with an exposure substrate (for example, an FPD substrate or a semiconductor substrate) using the mask. In this embodiment, a quartz substrate having a diameter of about 100 mm, a quartz substrate having a length of 450 mm, a width of 550 mm, and a thickness of 8 mm can be applied to a substrate having a diameter of about 50 to 100 mm and a rectangular substrate having a width of 300 mm or more , Substrates having a substrate size of 1000 mm or more can also be used.

Further, the surface of the transparent substrate 10 is polished to reduce the surface roughness of the transparent substrate 10. The roughness of the transparent substrate 10 can be, for example, 50 占 퐉 or less. As a result, the depth of focus of the mask is deepened, which contributes greatly to the formation of fine and highly precise patterns. The roughness of the transparent substrate is more preferably 20 m or less, and when it is 10 m or less, the contribution to fine and high-precision pattern formation becomes higher.

The light-shielding layer 11 is made of a metal chromium or a chromium compound (hereinafter also referred to as a chromium-based material), but is not limited thereto and may be a metal silicide-based material (for example, MoSi, TaSi, TiSi, WSi) , Nitride, and oxynitride are applicable. The thickness of the light-shielding layer 11 is not particularly limited, and may be a thickness (for example, 80 to 200 nm) at which a predetermined optical density or more can be obtained. The deposition method can be applied by electron beam deposition, laser deposition, atomic layer deposition (ALD), ion assisted sputtering, etc. Especially, in the case of large substrates, deposition with excellent uniformity of film thickness is possible by DC sputtering Do.

Next, as shown in Fig. 1 (b), a photoresist layer 12 is formed on the light-shielding layer 11. The photoresist layer 12 may be of a positive type or a negative type. As the photoresist layer 12, a liquid resist is used, but a dry film resist may be used.

Subsequently, as shown in Figs. 1 (c) and 1 (d), the photoresist layer 12 is exposed and developed to remove the region 12a to form a resist pattern 12P1 on the light shielding layer 11 (Fig. 1 (c)). The resist pattern 12P1 functions as an etching mask for the light shielding layer 11 and is appropriately shaped according to the etching pattern of the light shielding layer 11. [

1 (e), the light shielding layer 11 is etched in a predetermined pattern shape. Therefore, a light shielding layer 11P1 patterned in a predetermined shape is formed on the transparent substrate 10. [

The wet etching method or the dry etching method can be applied to the etching process of the light shielding layer 11, and in particular, when the substrate 10 is large, wet etching can be employed to realize an etching process with high in-plane uniformity .

The etching liquid of the light-shielding layer 11 can be appropriately selected. When the light-shielding layer 11 is a chromium-based material, for example, an aqueous solution of ceric ammonium nitrate and perchloric acid can be used.

This etching solution can protect the substrate 10 at the time of patterning the light shielding layer 11 because the selection ratio of the glass substrate is high. On the other hand, when the light-shielding layer 11 is made of a metal silicide-based material, for example, ammonium hydrogen fluoride may be used as the etching solution.

After patterning the light shielding layer 11P1, the resist pattern 12P1 is removed as shown in Fig. 1 (f). For removing the resist pattern 12P1, for example, an aqueous solution of sodium hydroxide can be used.

Next, as shown in Fig. 1 (g), the phase shift layer 13 is formed. The phase shift layer 13 is formed so as to cover the light shielding layer 11P1 on the transparent substrate 10.

As the deposition method of the phase shift layer 13, an electron beam (EB) deposition method, a laser deposition method, an atomic layer deposition (ALD) method, an ion assisted sputtering method or the like can be applied. It is possible to deposit with excellent thickness uniformity by adopting. In addition, the present invention is not limited to the DC sputtering method, and the AC sputtering method or the RF sputtering method may be applied.

The phase shift layer 13 is made of a chromium-based material. In particular, in this embodiment, the phase shift layer 13 is made of chromium oxide nitride. According to the chromium-based material, particularly good patterning property can be obtained on a large substrate. Further, metal silicide-based materials such as MoSi, TaSi, WSi, CrSi, NiSi, CoSi, ZrSi, NbSi, TiSi, or a compound thereof can be used instead of the chromium-based material. Al, Ti, Ni, or a compound thereof, or the like may also be used.

When the phase shift layer 13 made of chromium oxynitride is formed by the sputtering method, a mixed gas of a nitriding gas and an oxidizing gas, or a mixed gas of an inert gas, a nitriding gas, and an oxidizing gas may be used as a process gas. The deposition pressure may be, for example, 0.1 Pa to 0.5 Pa. As the inert gas, halogen, particularly argon, can be applied.

The oxidizing gas includes CO, CO ₂ , NO, N ₂ O, NO ₂ , O _2, and the like. The nitrifying gas includes NO, N ₂ O, NO ₂ , N _2, and the like. As the inert gas, Ar, He, Xe or the like is used, but generally Ar is used. Further, the mixed gas may further contain a carbonizable gas such as CH ₄ .

The flow rate (concentration) of the nitriding gas and the oxidizing gas in the mixed gas is an important parameter for determining the optical properties (transmittance, refractive index, etc.) of the phase shift layer 13. In this embodiment, the mixed gas is adjusted under the condition that the nitriding gas is 40% or more and 70% or less and the oxidizing gas is 9.2% or more and 10.4% or less. It is possible to optimize the refractive index, transmittance, reflectance, thickness, etc. of the phase shift layer 13 by adjusting the gas condition.

When the oxidizing gas is less than 9.2%, the oxygen concentration in the film is too low to lower the transmittance. When the oxidizing gas is more than 10.4%, the oxygen concentration in the film is too high, so that the deviation of the transmittance according to the wavelength of light becomes too large, and oxidation of the target can not be suppressed, and stable sputtering becomes difficult. As the oxidizing gas, carbon dioxide can be mentioned. When the nitriding gas is less than 40%, the oxidation of the target can not be suppressed and stable sputtering becomes difficult. When the nitriding gas is more than 90%, the oxygen concentration in the film becomes too low to obtain a desired refractive index. As the nitriding gas, nitrogen gas can be mentioned. By vapor deposition in a mixed gas atmosphere under the above conditions, for example, a phase shift layer having a transmittance of 1 to 20% with respect to the i-line can be obtained. The transmittance may be 0.5% or more.

The thickness of the phase shift layer 13 is such that the phase shift layer 13 can have a phase difference of 180 degrees with respect to light of one of g line, h line and i line in a wavelength range of 300 nm or more and 500 nm or less. The light having a phase difference of 180 DEG is inverted in phase and the light intensity is canceled by an interference effect between the light not passing through the phase shift layer 13 and the light. By this phase shift effect, a region in which the light intensity becomes minimum (for example, 0) is formed, so that the exposure pattern becomes clear, and a fine pattern can be formed with high precision.

In this embodiment, the light in the wavelength region is composite light (multicolor light) of i-line (wavelength 365 nm), h-line (wavelength 405 nm), and g-line (wavelength 436 nm) The phase shift layer 13 is formed to have a thickness capable of imparting a phase difference of 180 deg. The light of the target wavelength may be any one of i-line, h-line, and g-line, and may be light in other wavelength regions. The shorter the wavelength of the light to be inverted in phase, the finer the pattern can be formed.

In this embodiment, the phase shift layer 13 can be formed with a thickness such that the difference between the retardation imparted to the i-line and the retardation imparted to the g-line is 30 ° or less. As a result, a constant phase shift effect can be obtained with respect to light of each wavelength. For example, the phase shift layer can be formed to a thickness capable of imparting a phase difference of about 180 DEG (180 DEG +/- 10 DEG) to the h line which is an intermediate wavelength region of the composite wavelength. Then, since a phase difference close to 180 DEG can be given to any light of i-line and g-line, the same phase shift effect can be obtained for each light.

The thickness of the phase shift layer 13 is preferably uniform within the surface of the transparent substrate 10.

In this embodiment, the phase shift layer 13 is formed with a difference in thickness such that the difference in phase difference within the substrate plane is 20 DEG or less for each single wavelength of the g line, h line and i line. If the difference in the phase difference exceeds 20 DEG, the intensity of the light intensity is reduced due to the overlapping effect of the light intensity of the composite wavelength, and the patterning precision is lowered. The difference in the retardation may be 15 degrees or less, specifically 10 degrees or less, so that the patterning precision can be further improved.

The transmittance of the phase shift layer 13 may be, for example, in the range of 1% or more and 20% or less with respect to the i-line. The transmittance may be 0.5% or more. If the transmittance is less than 0.5%, it is difficult to obtain a sufficient phase shift effect, and it becomes difficult to expose a fine pattern with high precision. If the transmittance is 20% or more, the film formation rate is lowered and the productivity is deteriorated.

In the above range, further, the transmittance can be in the range of 2% or more and 15% or less. More specifically, the transmittance in the above range can be 3% or more and 10% or less.

The reflectance of the phase shift layer 13 is, for example, 40% or less. This makes it difficult to form a ghost pattern at the time of patterning the substrate (flat panel substrate or semiconductor substrate) using the phase shift mask, thereby ensuring good pattern accuracy.

The transmittance and reflectance of the phase shift layer 13 can be arbitrarily adjusted depending on the gas condition at the time of vapor deposition. According to the mixed gas condition described above, a transmittance of 1% or more and 20% or less and a reflectance of 40% or less with respect to the i-line can be obtained. The transmittance may be 0.5% or more.

The thickness of the phase shift layer 13 can be appropriately set within a range in which the above-described optical characteristics can be obtained. In other words, by optimizing the thickness of the phase shift layer 13, the above-described optical characteristics can be obtained. For example, the thickness of the phase shift layer 13 capable of obtaining the optical characteristics according to the gas condition is, for example, 100 nm or more and 130 nm or less. In this range, furthermore, the thickness of the phase shift layer 13 can be in the range of 110 nm or more and 125 nm or less.

For example, when the flow rate ratio of the mixed gas at the time of sputtering deposition is set to Ar: N ₂ : CO ₂ = 71: 21.5: 120 and the film thickness is 114 nm, the transmittance in the i-line is 3.10% , The retardation can be set to 180 °, the transmittance at the g-line can be set to 7.95%, and the retardation can be set to 150 °.

2 and 3 show experimental results showing the relationship between the deposition conditions at the time of deposition of the phase shift layer 13 and the phase difference of each wavelength component and the transmittance of i-line. In this example, N ₂ as the nitriding gas, CO ₂ as the oxidizing gas, and Ar as the inert gas were used. The deposition pressure was 0.4 Pa.

As in Experimental Example 2, the transmittance in the i-line was 3.10%, the retardation in the i-line was 180 °, and the transmittance in the g-line was in the range of 9.2% to 10.4% 7.95%. Further, the difference in transmittance between the i-line, the h-line, and the g-line can be suppressed to 5% or less by forming the phase shift layer with a thickness capable of imparting a phase difference of 180 deg. . In addition, the i-line transmittance can be set in the range of 1% to 10%.

On the other hand, in Experimental Example 1, in which the oxidizing gas was not in the range of 9.2% to 10.4%, the degree of oxidation of the film was small and the difference in transmittance between the i-line and the g-line could not be set within the required range even when the thickness was large. In Experimental Examples 3 and 4, although the transmittance was low, the difference in transmittance between i-line and g-line could be reduced.

Subsequently, as shown in FIG. 1 (h), a photoresist layer 14 is formed on the phase shift layer 13. The photoresist layer 14 may be a positive type or a negative type. As the photoresist layer 14, a liquid resist is used.

Next, as shown in Figs. 1 (j) and 1 (k), the photoresist layer 14 is exposed and developed to form a resist pattern 14P1 on the phase shift layer 13. The resist pattern 14P1 functions as an etching mask for the phase shift layer 13 and is appropriately shaped according to the etching pattern of the phase shift layer 13. [

Then, as shown in Fig. 1 (m), the phase shift layer 13 is etched to a predetermined pattern shape. Therefore, a phase shift layer 13P1 patterned in a predetermined shape is formed on the transparent substrate 10. [

A wet etching method or a dry etching method can be applied to the etching process of the phase shift layer 13, and in particular, when the substrate 10 is large, an etching process with high in-plane uniformity can be realized by employing the wet etching method.

The etching solution of the phase shift layer 13 can be appropriately selected, and in this embodiment, an aqueous solution of ammonium ceric nitrate and perchloric acid can be used. Such an etchant can protect the substrate 10 at the time of patterning the phase shift layer 13 because the selection ratio of the glass substrate is high.

After patterning the phase shift layer 13P1, the resist pattern 14P1 is removed as shown in Fig. 1 (n). For removing the resist pattern 14P1, for example, an aqueous solution of sodium hydroxide can be used.

As described above, the phase shift mask 1 according to the present embodiment is manufactured. According to the phase shift mask 1 of the present embodiment, the phase shift layer 13P1 having the above-described configuration is formed around the light shielding layer pattern 11P1. Thus, in forming an exposure pattern for a substrate to be exposed using light of a complex wavelength including g-line (436 nm), h-line (405 nm), and i-line (365 nm) , And g-line can be suppressed to 5% or less, and the pattern accuracy based on the phase shift effect can be improved, so that a fine and high-precision pattern can be formed. Particularly, according to this embodiment, the use of an exposure technique in which light (g line, h line and i line) having different wavelengths in the above wavelength range are combined becomes more remarkable.

Hereinafter, a method for manufacturing a flat panel display using the phase shift mask 1 according to the present embodiment will be described.

First, a photoresist layer is formed on the surface of a glass substrate on which an insulating layer and a wiring layer are formed. For the formation of the photoresist layer, for example, a spin coater is used. The photoresist layer is subjected to an exposure treatment using the phase shift mask 1 after a heating (baking) treatment is applied. In the exposure step, the phase shift mask 1 is disposed close to the photoresist layer. The surface of the glass substrate is irradiated with a composite wavelength including a g line (436 nm), h line (405 nm), and i line (365 nm) of 300 nm or more and 500 nm or less through the phase shift mask (1). In this embodiment, composite light of g-line, h-line and i-line is used as the light of the complex wavelength. Therefore, the exposure pattern corresponding to the mask pattern of the phase shift mask 1 is transferred to the photoresist layer.

According to this embodiment, the phase shift mask 1 can suppress the difference in transmittance between the i-line, the h-line, and the g-line to 5% or less, And a phase shift layer 13P1 capable of providing a phase difference of 180 DEG. Therefore, according to the above-described manufacturing method, it is possible to improve the pattern accuracy based on the phase shift effect by using the light in the wavelength region, and to further deepen the depth of focus, fine and highly precise pattern formation becomes possible . Thus, a flat panel display of high image quality can be manufactured.

According to the experiment of the present inventors, when exposure is performed using a mask not including the phase shift layer, a pattern width difference of 30% or more occurs with respect to a target line width (2 탆). However, in the phase shift mask 1 ), It can be suppressed to a difference of about 7%.

&Lt; Embodiment 2 >

4 is a process diagram for explaining the method of manufacturing the phase shift mask according to the second embodiment of the present invention. 4, parts corresponding to those in Fig. 1 are denoted by the same reference numerals, and a detailed description thereof will be omitted.

In the phase shift mask 2 (Fig. 4 (J)) of the present embodiment, alignment marks for alignment are formed in peripheral portions, and the alignment marks are formed of the light shielding layer 11P2. Hereinafter, a method of manufacturing the phase shift mask 2 will be described.

First, the light shielding layer 11 is formed on the transparent substrate 10 (Fig. 4 (A)). Next, a photoresist layer 12 is formed on the light shielding layer 11 (Fig. 4 (B)). The photoresist layer 12 may be a positive type or a negative type. Then, the photoresist layer 12 is exposed and developed to form a resist pattern 12P2 on the light shielding layer 11 (Fig. 4 (C)).

The resist pattern 12P2 functions as an etching mask for the light shielding layer 11 and is appropriately shaped according to the etching pattern of the light shielding layer 11. [ 4C shows an example in which a resist pattern 12P2 is formed so that the light shielding layer can remain over a predetermined range around the periphery of the substrate 10. [

Subsequently, the light shielding layer 11 is etched in a predetermined pattern shape. Thus, a light shielding layer 11P2 patterned in a predetermined shape is formed on the transparent substrate 10 (Fig. 4 (D)). After patterning the light shielding layer 11P2, the resist pattern 12P2 is removed (Fig. 4 (E)). For removing the resist pattern 12P2, for example, an aqueous solution of sodium hydroxide can be used.

Next, a phase shift layer 13 is formed. The phase shift layer 13 is formed so as to cover the light shielding layer 11P2 on the transparent substrate 10 (Fig. 4 (F)). The phase shift layer 13 is made of a chromium oxynitride-based material and is deposited by DC sputtering. In this case, a mixed gas of a nitriding gas and an oxidizing gas, or a mixed gas of an inert gas, a nitriding gas, and an oxidizing gas may be used as the process gas. The phase shift layer 13 is formed under the same deposition conditions as those of the first embodiment described above.

Thereafter, a photoresist layer 14 is formed on the phase shift layer 13 (Fig. 4 (G)).

Next, the photoresist layer 14 is exposed and developed to form a resist pattern 14P2 on the phase shift layer 13 (Fig. 4 (H)). The resist pattern 14P2 functions as an etching mask for the phase shift layer 13 and is appropriately shaped according to the etching pattern of the phase shift layer 13. [

Subsequently, the phase shift layer 13 is etched to a predetermined pattern shape. Thus, a phase shift layer 13P2 patterned in a predetermined shape is formed on the transparent substrate 10 (Fig. 4 (I)). After the patterning of the phase shift layer 13P2, the resist pattern 14P2 is removed (Fig. 4 (J)). For removing the resist pattern 14P2, for example, an aqueous solution of sodium hydroxide can be used.

As described above, the phase shift mask 2 according to this embodiment is manufactured. According to the phase shift mask 2 of this embodiment, since the alignment mark is formed of the light shielding layer 11P2, it is easy to optically recognize the alignment mark, and high-precision alignment becomes possible.

This embodiment can be implemented in combination with the above-described first embodiment.

Further, the phase shift layer 13 can function as a halftone layer (semi-transparent layer). In this case, it is possible to make a difference in exposure amount between light transmitted through the phase shift layer 13 and light not transmitted.

Although the embodiment of the present invention has been described above, the present invention is not limited thereto, and various modifications are possible based on the technical idea of the present invention.

For example, in the first embodiment described above, the phase shift layer is deposited and patterned after patterning the light shielding layer. However, the present invention is not limited to this, and it is possible to perform deposition and patterning of the light shielding layer after deposition of the phase shift layer and patterning. have. That is, it is possible to change the stacking order of the light shielding layer and the phase shift layer. In this case, an unillustrated etching stopper layer mainly composed of at least one metal selected from Ni, Co, Fe, Ti, Si, Al, Nb, Mo, W and Hf is formed between the light- .

In the above embodiment, the light-shielding layer 11P1 is formed by forming the light-shielding layer 11 on the entire surface of the substrate 10 and then etching the necessary portion. Instead, The light-shielding layer 11 can be formed. After the formation of the light shielding layer 11, the light shielding layer 11P1 can be formed in a necessary region by removing the resist pattern (lift-off method).

Although the embodiment of the present invention has been described above, the present invention is not limited thereto, but can be appropriately changed without departing from the gist of the invention.

1, 2: phase shift mask
10: transparent substrate
11, 11P1: Shading layer
12P1, 14P1: resist pattern
13P1: phase shift layer

Claims (3)

A step of forming a light-shielding layer mainly composed of Cr patterned on a transparent substrate;
The target of the chromium-based material is sputtered in an atmosphere of a mixed gas containing an inert gas, a nitriding gas, and an oxidizing gas, so as to have a phase difference of about 180 degrees with respect to the i line, Of 10.4% or less and making the difference between the g-line transmittance and the i-line transmittance 5% or less; and patterning the phase shift layer with Cr as a main component;
Wherein the phase shift mask is formed on the substrate. A light-shielding layer mainly composed of Cr formed on a transparent substrate; And
a phase shift layer containing Cr as a main component and having a phase difference of about 180 deg. with respect to the i-line and capable of making the difference between the g-line transmittance and the i-line transmittance 5% or less;
Wherein the phase shift mask comprises a phase shift mask. 3. The method of claim 2,
The light shielding layer is formed on the surface of the transparent substrate, the phase shift layer is formed on the light shielding layer,
Wherein the phase shift layer is formed on the surface of the transparent substrate and at least one kind of metal selected from the group consisting of Ni, Co, Fe, Ti, Si, Al, Nb, Mo, Wherein an etching stopper layer as a main component is formed, and the light shielding layer is formed on the etching stopper layer.

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