TWI698702B - Manufacturing method of phase shift mask base and phase shift mask using the same, and manufacturing method of display device - Google Patents

Abstract

The present invention provides a phase shift mask substrate used in the formation of a phase shift mask for a display device with excellent pattern cross-sectional shape and excellent CD uniformity and formed with fine patterns. The phase shift film disposed on the transparent substrate has first and second functional layers, and an intermediate layer arranged between them. The first and second functional layers include chromium-based materials containing chromium, oxygen and nitrogen, and chromium is 30 to 70 atomic %, oxygen is 20 to 60 atomic %, and nitrogen is 0.4 to 30 atomic %. The content of nitrogen contained in the first functional layer is the same as or more than the nitrogen contained in the second functional layer The content of oxygen contained in the second functional layer is higher than that of the oxygen contained in the first functional layer. The intermediate layer contains chromium and carbon. The content of chromium is 55-90 atomic %, and the content of carbon The rate is 10 to 45 atomic %, and the content of chromium contained in the intermediate layer is higher than the content of chromium contained in the first and second functional layers.

Description

Phase shift photomask substrate, manufacturing method of phase shift photomask using the same, and manufacturing method of display device

The invention relates to a phase shift mask substrate, a method for manufacturing a phase shift mask using the same, and a method for manufacturing a display device.

In recent years, with the high resolution and high definition of display devices such as FPD (Flat Panel Display), there is a demand for a pattern with excellent cross-sectional shape and excellent CD (Critical Dimension) uniformity and formation of Phase shift mask for display devices with fine patterns.

In addition, due to the lower prices of display devices such as FPDs, it is necessary to reduce the manufacturing cost of the phase shift mask. In the case of the previous phase shift mask base with a light-shielding film formed on the phase shift film, the resist film pattern is used as a mask and the light-shielding film is etched to form the light-shielding film pattern. The light-shielding film pattern is used as a mask and the phase shift film is etched to form a phase shift film pattern. After that, the resist film pattern is peeled off, and the light-shielding film pattern is peeled off to produce a phase shift film pattern. Shift the mask. On the other hand, in the case of a phase shift mask base with no light-shielding film formed on the phase shift film, the step of forming the light-shielding film pattern on the phase shift film and the peeling step are not required, which can reduce the manufacturing cost.

To cope with the situation in recent years, the following phase shift masks for display devices are required, which are manufactured using a phase shift mask substrate without a light-shielding film formed on the phase shift film, and have an excellent pattern cross-sectional shape and Excellent CD uniformity and fine patterns formed.

For example, Patent Document 1 proposes a phase shift mask base for a display device, which includes a phase shift film composed of two or more thin films laminated on a transparent substrate. Although the thin films constituting the phase shift film have different compositions, they collectively contain substances that can be etched by the same etching solution, and have different etching speeds due to their different compositions. In Patent Document 1, during the patterning of the phase shift film, the etching speed of each thin film constituting the phase shift film is adjusted by steeply forming the profile gradient of the edge portion of the phase shift film pattern.

Furthermore, in Patent Document 1, a phase shift mask substrate for a display device is also proposed, in which a light-shielding film, a semi-transmissive film, an etching stop film, and a hard light are used on or under the phase inversion film. As a representative, the mask film is configured with a functional film including one or more films required for a pattern for transfer.

[Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2014-26281

The phase shift film used in the phase shift mask for the previously proposed display device does not consider the resistance caused by the reflection of the laser drawing light used in the patterning of the resist film used to form the phase shift film pattern. Designed for the influence of etchant film. Therefore, the reflectivity of the phase shift film to the laser drawing light exceeds 20%. As a result, there are cases where standing waves are generated in the resist film, and consequently, the CD uniformity of the resist film pattern deteriorates, and even the resist film pattern is used as a mask and patterned to form a phase The CD uniformity of the film transfer pattern cannot meet the value required in recent years.

Therefore, the present invention was made in view of the above-mentioned problems, and the purpose is to reduce the reflectance of the film surface to light in the 350nm~436nm wavelength region used as laser drawing light. Phase shift film to provide a phase shift mask substrate used in the formation of a phase shift mask for display devices with excellent pattern cross-sectional shape and excellent CD uniformity and formed with fine patterns, and a phase using the same Manufacturing method of shifting mask. Furthermore, the purpose is to provide a high-resolution, high-definition manufacturing method for a display device by using a phase shift mask for a display device with excellent pattern cross-sectional shape and excellent CD uniformity and fine patterns formed.

In order to achieve the above-mentioned object, the present inventors have made diligent research and obtained the following knowledge: by constructing a phase shift film containing a chromium-based material with at least three layers, and studying the composition or film thickness of each layer constituting the phase shift film, The transmittance and phase difference of the phase shift film to the exposure light meet the specific optical characteristics required as a phase shift film, while reducing the film surface reflectivity of the phase shift film to light in the 350nm~436nm wavelength region.

This invention is based on this knowledge, and has the following structure.

(Composition 1)

A phase shift mask substrate, characterized in that it is provided with a phase shift film containing a chromium-based material on a transparent substrate, and the phase shift film has a first functional layer constituting its lower layer and a second function constituting its upper layer Layer and an intermediate layer arranged between the first functional layer and the second functional layer, the first functional layer and the second functional layer include chromium-based materials containing chromium, oxygen and nitrogen, and the chromium is 30 to 70 Atomic %, oxygen is 20-60 atomic%, nitrogen is 0.4-30 atomic%, the content of nitrogen contained in the first functional layer is the same as or more than the content of nitrogen contained in the second functional layer The content of oxygen contained in the second functional layer is greater than the content of oxygen contained in the first functional layer. The intermediate layer contains chromium and carbon. The content of chromium is 55 to 90 atomic %. Content rate The content of chromium contained in the intermediate layer is greater than the content of chromium contained in the first functional layer and the second functional layer.

(Composition 2)

The phase shift mask substrate described in Composition 1, characterized in that: the first functional layer has the function of mainly adjusting the transmittance and phase difference of the exposed light, and the second functional layer has the function of reducing the resistance from the phase shift film As a function of the reflectance of side incident light, the film thickness of the first functional layer is thicker than the film thickness of the second functional layer.

(Composition 3)

The phase shift mask substrate described in Composition 1 or 2, characterized in that the first functional layer includes chromium nitride, and the second functional layer includes chromium oxide III formed by bonding chromium and oxygen.

(Composition 4)

The phase shift mask substrate as described in any one of compositions 1 to 3, wherein the intermediate layer further includes a chromium-based material containing oxygen, the first functional layer, the intermediate layer, and the second functional layer Contains chromium oxide III.

(Composition 5)

The phase shift mask substrate described in any one of compositions 1 to 4 is characterized in that: the surface reflectivity of the phase shift film to light incident from the side of the phase shift film is in the wavelength region of 350 to 436 nm, Less than 15%.

(Composition 6)

The phase shift mask base described in any one of compositions 1 to 5 is characterized in that the back surface reflectivity of the phase shift film to light incident from the transparent substrate side is 20 in the wavelength region of 313 to 436 nm %the following.

(Composition 7)

The phase shift mask base as described in any one of Compositions 1 to 6, characterized in that a light-shielding film pattern is provided between the transparent substrate and the phase shift film.

(Composition 8)

A method for manufacturing a phase shift mask, which is characterized in that it has the following steps: on the above-mentioned phase shift film of the phase shift mask substrate as described in any one of 1 to 7, by using a phase shift film selected from 350nm~436nm The step of forming a resist film pattern by drawing and developing laser light of any wavelength in the wavelength range; and using the resist film pattern as a mask and etching the phase shift film, and The step of forming a phase shift film pattern on the above-mentioned transparent substrate.

(Composition 9)

A method of manufacturing a display device is characterized by the steps of: placing the phase shift mask manufactured by the method of manufacturing the phase shift mask as described in Composition 8 on the mask stage of the exposure device; and The step of irradiating the exposure light with the light shift mask and transferring the above-mentioned phase shift film pattern to the resist film formed on the substrate of the display device.

(Composition 10)

The manufacturing method of the display device as described in Composition 9, characterized in that the light for the above exposure includes a composite light of light of a plurality of wavelengths selected from the wavelength region of 313 nm to 436 nm.

As described above, the phase shift mask base of the present invention is provided with a phase shift film containing a chromium-based material on a transparent substrate. The phase shift film has a first functional layer constituting its upper layer and a second functional layer constituting its lower layer. , And an intermediate layer arranged between the first functional layer and the second functional layer, above The first functional layer and the second functional layer include chromium-based materials containing chromium, oxygen and nitrogen, chromium is 30 to 70 atomic %, oxygen is 20 to 60 atomic %, and nitrogen is 0.5 to 30 atomic %. The content rate of nitrogen contained in the functional layer is the same as or greater than the content rate of nitrogen contained in the second functional layer, and the content rate of oxygen contained in the second functional layer is higher than that in the first functional layer The content of oxygen contained in the intermediate layer contains chromium and carbon. The content of chromium is 55 to 90 atomic %, and the content of carbon is 10 to 45 atomic %. The content of chromium in the intermediate layer is high The content rate of chromium contained in the first functional layer and the second functional layer. Therefore, by using the phase shift mask substrate, it is possible to manufacture a phase shift mask with excellent pattern cross-sectional shape and excellent CD uniformity and fine patterns formed. Moreover, by using this phase shift mask, a high-resolution, high-definition display device can be manufactured.

10: Phase shift mask substrate

20: Transparent substrate

30: Phase shift film

31: Phase shift layer

32: reflectivity reduction layer

33: Metal layer

40: Shading film pattern

Figure 1 is a schematic diagram showing the film composition of the phase shift mask substrate.

Fig. 2 is a schematic diagram showing another film composition of the phase shift mask substrate.

Fig. 3 shows the reflectance spectrum of the phase shift film of the phase shift mask substrate in Examples 1, 2, 3 and Comparative Example 1.

4 shows the back reflectance spectra of the phase shift film of the phase shift mask substrate in Examples 1, 2, 3 and Comparative Example 1.

FIG. 5 is a graph showing the composition analysis result in the depth direction of the phase shift film of the phase shift mask substrate in Example 1. FIG.

6 is a graph showing the composition analysis result of the phase shift film of the phase shift mask substrate in Example 2 in the depth direction.

FIG. 7 is a graph showing the composition analysis result of the phase shift film of the phase shift mask substrate in Example 3 in the depth direction.

Hereinafter, the embodiments of the present invention will be described in detail while referring to the drawings. In addition, the following embodiment is an aspect when the present invention is embodied, and the present invention is not limited to the scope thereof. Furthermore, in the figures, for the same or equivalent parts, the same symbols are attached and the descriptions thereof are simplified or omitted.

Implementation mode 1.

In the first embodiment, the phase shift mask substrate will be described.

FIG. 1 is a schematic diagram showing the film composition of the phase shift mask substrate 10. The phase shift mask base 10 includes a transparent substrate 20 that is transparent to exposure light, and a phase shift film 30 containing a chromium-based material disposed on the transparent substrate 20. When assuming that there is no surface reflection loss, the transparent substrate 20 has a transmittance of 85% or more to the exposed light, and preferably has a transmittance of 90% or more. The phase shift film 30 has, from the transparent substrate 20 side, a phase shift layer 31 as a first functional layer constituting its lower layer, a reflectance reducing layer 32 as a second functional layer constituting its upper layer, and a reflectance reducing layer 32 arranged on the phase shift layer 31 and The metal layer 33 of the intermediate layer between the reflectance reducing layers 32. Each of the phase shift layer 31, the metal layer 33, and the reflectance reduction layer 32 is formed of a chromium-based material containing chromium (Cr). Therefore, the phase shift layer 31, the metal layer 33, and the reflectance reduction layer 32 can be etched by the same etching solution.

The phase shift layer 31 is disposed on the main surface of the transparent substrate 20. The phase shift layer 31 has the function of mainly adjusting the transmittance and phase difference of the exposed light. The phase shift layer 31 is the layer having the thickest film thickness in the phase shift film 30 compared to the film thickness of the reflectance reduction layer 32 and the metal layer 33. In addition, the content rate of each element which comprises the following phase shift layer 31, the metal layer 33, and the reflectance reduction layer 32 is set to the value measured by X-ray photoelectron spectroscopy (XPS, ESCA).

The phase shift layer 31 includes a chromium-based material containing chromium (Cr), oxygen (O) and nitrogen (N). With regard to the average content of each element, chromium is 30 to 70 atomic %, oxygen is 20 to 60 atomic %, and nitrogen It is 0.4 to 30 atomic %. In addition, regarding the phase shift layer 31, it is preferable to include chromium from the viewpoint of forming an excellent pattern cross-sectional shape by wet etching in the form of the bonding state (chemical state) of the components constituting the phase shift layer 31 Chromium nitrides bonded with nitrogen, especially chromium nitride (CrN) or chromium nitride (Cr ₂ N). Furthermore, the phase shift layer 31 may also be made of a chromium-based material containing at least one of carbon (C) and fluorine (F). For example, as a material for forming the phase shift layer 31, CrON, CrOCN, and CrFCON can be cited.

The phase shift layer 31 can be formed by sputtering.

The reflectance reduction layer 32 is disposed on the upper side of the phase shift layer 31. The reflectance reducing layer 32 mainly has the function of reducing the reflectance of light incident from the phase shift film 30 side (that is, the side of the reflectance reducing layer 32 opposite to the transparent substrate 20 side). The reflectance reduction layer 32 is to reduce the reflectance of the phase shift film 30 by the interference effect caused by the reflection generated by the interface between the metal layer 33 and the reflectance reduction layer 32 and the reflection generated by the surface of the reflectance reduction layer 32 And the layer adjusted by film thickness.

The reflectance reduction layer 32 includes a chromium-based material containing chromium (Cr), oxygen (O), and nitrogen (N). With regard to the average content of each element, chromium is 30 to 70 atomic% and oxygen is 20 to 60 atomic %. Nitrogen is 0.4 to 30 atomic %. Also, regarding the reflectance reducing layer 32, it is preferable to obtain an excellent pattern cross-sectional shape produced by wet etching in the form of the bonding state (chemical state) of the components constituting the reflectance reducing layer 32 It contains chromium oxide formed by bonding chromium and oxygen, especially chromium oxide III (Cr ₂ O ₃ ). Furthermore, the reflectance reduction layer 32 may also be made of a chromium-based material containing at least one of carbon (C) and fluorine (F). For example, as a material for forming the reflectance reduction layer 32, CrON, CrOCN, and CrFON can be cited.

In terms of the effect of reducing the reflectance of light incident from the side of the phase shift film 30 (the surface side of the reflectance reducing layer 32), and the viewpoint of forming an excellent cross-sectional shape of the pattern by wet etching as a whole of the phase shift film 30 In other words, it is assumed that the content rate of nitrogen (N) contained in the phase shift layer 31 is the same as or more than The content rate of nitrogen (N) contained in the reflectance reduction layer 32, and the content rate of oxygen (O) contained in the reflectance reduction layer 32 is higher than the content rate of oxygen (O) contained in the phase shift layer 31 The state. Also, in terms of the effect of reducing the reflectance of the film surface, it is preferable that the content of oxygen (O) contained in the reflectance reducing layer 32 is higher than the content of oxygen (O) contained in the phase shift layer 31 The ratio is at least 1 atomic% or more, preferably 5 atomic% or more.

The reflectance reduction layer 32 can be formed by sputtering.

The metal layer 33 is disposed between the phase shift layer 31 and the reflectance reduction layer 32. The metal layer 33 has the function of adjusting the transmittance of the exposed light, and has the function of reducing the reflectance of the light incident from the side of the phase shift film 30 in combination with the reflectance reducing layer 32. Furthermore, it has a function of combining with the phase shift layer to reduce the reflectance of light incident from the transparent substrate 20 side.

The metal layer 33 contains chromium (Cr) and carbon (C). Regarding the average content of each element, the content of chromium (Cr) is 55 to 90 atomic %, and the content of carbon (C) is 10 to 45 atomic %. Furthermore, in relation to the phase shift layer 31 and the reflectance reduction layer 32, the metal layer 33 has a higher content of chromium than the chromium contained in the phase shift layer 31 and the reflectance reduction layer 32. Containment rate. By setting the carbon (C) content to 10 atomic% or more, it is possible to suppress the corrosion of the cross-sectional shape of the metal layer 33 caused by the increase in the side etching rate. In addition, by setting the content of carbon (C) to be 45 atomic% or less, the cross-sectional shape of the metal layer 33 can be suppressed from becoming a tapered shape. By setting the carbon (C) content contained in the metal layer 33 to the above-mentioned appropriate range, a pattern can be formed on the metal layer 33 by a suitable photomask process. In addition, the metal layer 33 may also be made of a chromium-based material containing at least one of nitrogen (N), oxygen (O), and fluorine (F). For example, as a material for forming the metal layer 33, CrC, CrCN, CrCO, CrCF, and CrCON can be cited. Among them, the metal layer 33 is preferably made of a chromium-based material containing chromium (Cr), carbon (C), and oxygen (O). In addition, from the viewpoint of obtaining an excellent pattern cross-sectional shape produced by wet etching in the form of the bonding state (chemical state) of the components constituting the phase shift layer 31, the reflectance reduction layer 32, and the metal layer 33, Furthermore, it is preferable to include chromium oxide III (Cr ₂ O ₃ ) in all the layers.

By providing the metal layer 33, the sheet resistance of the phase shift film is reduced, so that the charge accumulation of the phase shift mask substrate and the phase shift mask can be prevented. When the metal layer 33 is not provided, the electricity generated when the phase shift mask substrate and the phase shift mask enter and exit from the housing will not leak out, and the electricity will be stored in the phase shift mask substrate and the phase shift mask. Easy to attach foreign matter. In addition, when a small pattern is formed on the phase shift mask, electricity jumps from the pattern to the pattern, which is likely to cause electrostatic damage.

The metal layer 33 can be formed by a sputtering method.

The metal layer 33 preferably has an extinction coefficient higher than that of the reflectance reducing layer 32 in the wavelength region of 350 nm to 436 nm. Moreover, it is preferable to have an extinction coefficient higher than that of the reflectance reduction layer 32 in the wavelength region of 313 nm to 436 nm.

The difference between the extinction coefficient of the metal layer 33 and the extinction coefficient of the reflectance reducing layer 32 is preferably 1.5 to 3.5, more preferably 1.8 to 3.5. If the difference in extinction coefficient is 1.5 to 3.5, the reflectance in the above-mentioned wavelength region (the wavelength region of 350 nm to 436 nm, or the wavelength region of 313 nm to 436 nm) at the interface between the metal layer 33 and the reflectance reducing layer 32 can be increased, so It is preferable to further exert the reflectance reduction effect.

Furthermore, the metal layer 33 preferably has an extinction coefficient higher than that of the phase shift layer 31 in the wavelength region of 350 nm to 436 nm. Moreover, it is preferable to have an extinction coefficient higher than that of the phase shift layer 31 in the wavelength region of 313 nm to 436 nm.

The extinction coefficient can be measured with n & k analyzer or ellipsometer.

The metal layer 33 has a chromium (Cr) content rate (at%) higher than the chromium (Cr) content rate (at%) of the phase shift layer 31 and the reflectance reducing layer 32.

The average Cr content of the metal layer 33 and the average Cr content of the phase shift layer 31 and the reflectance reduction layer 32 The difference in the rate is preferably 10 to 80 atomic %, more preferably 15 to 80 atomic %. If the difference in the average Cr content is 10 to 80 atomic%, the above-mentioned wavelength region (350nm~436nm wavelength region, or 313nm~436nm wavelength region) of the interface between the metal layer 33 and the reflectance reduction layer 32 can be increased The reflectance is better, so the reflectance reduction effect is further exerted.

The difference between the average Cr content of the metal layer 33 and the average Cr content of the phase shift layer 31 and the reflectance reducing layer 32 is further preferably set to 15-60 atomic %, and more preferably set to 20-50 atomic %. By setting the difference in the average Cr content in the above range, the light incident from the side of the reflectance reduction layer exerts the above-mentioned wavelength region of the interface between the metal layer 33 and the reflectance reduction layer 32 (the wavelength region of 350 nm to 436 nm, or In addition to the reflectance reduction effect in the wavelength region of 313nm~436nm), the light incident from the transparent substrate side is exerted in the above-mentioned wavelength region (wavelength region of 313nm~436nm) at the interface between the metal layer 33 and the phase shift layer 31 The reflectivity reduction effect is better.

Furthermore, the etching rate of the metal layer 33 can be adjusted by making the chromium (Cr) a chromium-based material containing nitrogen (N), oxygen (O), carbon (C), and fluorine (F). For example, by making chromium (Cr) contain carbon (C) or fluorine (F), the wet etching rate can be slowed down, and by making chromium (Cr) contain nitrogen (N) or oxygen (O), the wet etching can be accelerated Etching speed. Taking into account the wet etching speed of the phase shift layer 31 and the reflectance reduction layer 32 formed on and under the metal layer 33, the phase shift after etching can be achieved by adding the above elements to chromium to make it a chromium-based material The cross-sectional shape of the film 30 becomes good.

Each of the phase shift layer 31, the metal layer 33, and the reflectance reduction layer 32 preferably has a refractive index of 2.0 or more in the wavelength region of 350 nm to 436 nm. If it has a refractive index of 2.0 or more, in order to obtain the required optical properties (transmittance and retardation), the required film thickness of the phase shift film 30 can be made thinner. Therefore, the phase shift mask produced by using the phase shift mask substrate 10 provided with the phase shift film 30 can have a phase shift film pattern with excellent pattern cross-sectional shape and excellent CD uniformity.

The refractive index can be measured with an n & k analyzer or an ellipsometer.

With the layered structure of the phase shift layer 31, the metal layer 33, and the reflectance reduction layer 32, the phase shift film 30 has specific optical characteristics for the transmittance and phase difference of the exposed light.

The transmittance of the phase shift film 30 to exposure light satisfies the value required for the phase shift film 30. The transmittance of the phase shift film 30 is preferably 1% to 30%, more preferably 2% to 20%, with respect to the light of a specific wavelength contained in the exposure light (hereinafter referred to as the representative wavelength). The best is 3%~10%. That is, when the exposure light is a composite light including light in the wavelength range of 313 nm or more and 436 nm or less, the phase shift film 30 has the above-mentioned transmittance for the light of the representative wavelength included in the wavelength range. For example, when the exposure light is a composite light including j-line, i-line, h-line, and g-line, the phase shift film 30 has the above-mentioned transmission for any of j-line, i-line, h-line, and g-line rate.

The phase difference of the phase shift film 30 with respect to the exposure light satisfies the value required as the phase shift film 30. The phase difference of the phase shift film 30 is preferably 160° to 200°, and more preferably 170° to 190° with respect to the light of the representative wavelength included in the exposure light. Because of this property, the phase of the representative wavelength light contained in the exposure light can be changed by 160°~200°. Therefore, a phase difference of 160-200° occurs between the light of the representative wavelength passing through the phase shift film 30 and the light of the representative wavelength only passing through the transparent substrate 20. That is, when the exposure light is a composite light including light in the wavelength range of 313 nm or more and 436 nm or less, the phase shift film 30 has the above-mentioned phase difference with respect to the light of the representative wavelength included in the wavelength range. For example, when the exposed light is a composite light including j-line, i-line, h-line, and g-line, the phase shift film 30 has the above-mentioned phase for any of the j-line, i-line, h-line, and g-line difference.

The transmittance and phase difference of the phase shift film 30 can be controlled by adjusting the composition and thickness of each of the phase shift layer 31, the metal layer 33, and the reflectance reduction layer 32 constituting the phase shift film 30. Therefore, in this embodiment, the composition and thickness of each of the phase shift layer 31, the metal layer 33, and the reflectance reduction layer 32 are adjusted so that the transmittance and retardation of the phase shift film 30 have the above-mentioned specific optical characteristics. again Moreover, the transmittance of the phase shift film 30 is mainly affected by the composition and thickness of the phase shift layer 31 and the metal layer 33. The refractive index of the phase shift film 30 is mainly affected by the composition and thickness of the phase shift layer 31.

The transmittance and phase difference can be measured using a phase shift measuring device or the like.

The film surface reflectivity of the phase shift film 30 to light incident from the side of the phase shift film 30 is 15% or less in the wavelength region of 350 nm to 436 nm. Furthermore, it is preferably 22.5% or less in the wavelength region of 313 nm to 436 nm. That is, the film surface reflectance of the phase shift film 30 to light incident from the side of the phase shift film 30 is 15% or less in the wavelength region of 350 nm to 436 nm, and it is preferable to expand the wavelength region to 313 nm to 436 nm. 22% or less. If the reflectance of the phase shift film 30 is less than 15% in the wavelength region of 350nm~436nm, the reflectance of the film surface of the laser drawing light will decrease, so a phase shift mask with excellent CD uniformity can be formed . In addition, if the surface reflectance of the phase shift film 30 is 22.5% or less in the wavelength region of 313 nm to 436 nm, the reflectance of the film surface to the exposure light decreases, so when the pattern formed on the phase shift mask is transferred, It can prevent the blur (glare) of the transfer pattern caused by the reflected light from the substrate of the display device. The reflectance of the phase shift film 30 is preferably in the range of 313 nm to 436 nm, preferably 20% or less, and more preferably 15% or less.

The variation range of the reflectance of the film surface of the phase shift film 30 is preferably 9% or less in the wavelength region of 350 nm to 436 nm, and more preferably 8.5% or less. In addition, it is preferably 12.5% or less in the wavelength range of 313 nm to 436 nm, and more preferably 12%. That is, the variation range of the surface reflectance of the phase shift film 30 is preferably 9% or less in the wavelength region of 350 nm to 436 nm, and more preferably 8.5% or less, even if the wavelength region is enlarged to 313 nm. 436 nm is also 12.5% or less, and furthermore, it is also 12% or less.

The film surface reflectance of the phase shift film 30 and its variation range can be adjusted by adjusting the refractive index, extinction coefficient and thickness of each of the phase shift layer 31, the metal layer 33 and the reflectance reduction layer 32 constituting the phase shift film 30 And control. The extinction coefficient and refractive index can be controlled by adjusting the composition. Therefore, in this embodiment, the phase shift layer 31 and the metal layer 33 are adjusted in such a way that the surface reflectance of the phase shift film 30 and its variation range have the above-mentioned specific physical properties. And the composition and thickness of each of the reflectance reduction layer 32. Furthermore, the film surface reflectance of the phase shift film 30 and its variation range are mainly affected by the composition and thickness of each of the metal layer 33 and the reflectance reduction layer 32.

The reflectance of the film surface can be measured using a spectrophotometer or the like. The variation range of the reflectance of the film surface is calculated from the difference between the maximum reflectance and the minimum reflectance in the wavelength region of 350nm~436nm or 313nm~436nm.

The phase shift layer 31 may include a single film with a uniform composition, may include a plurality of films with different compositions, or may include a single film with a composition that changes continuously in the thickness direction. The same applies to the metal layer 33 and the reflectance reduction layer 32.

In addition, the interface between the phase shift layer 31 and the metal layer 33, and the interface between the metal layer 33 and the reflectance reduction layer 32 may have elements constituting each of the phase shift layer 31, the metal layer 33, and the reflectance reduction layer 23. The composition gradient area of the composition gradient. Furthermore, in the composition gradient area, the composition gradient may be continuously formed throughout the entire area, or may be formed stepwise, and further, part of the composition gradient may be formed stepwise, and the other part may be formed continuously.

FIG. 2 is a schematic diagram showing another film composition of the phase shift mask substrate 10. As shown in FIG. 2, the phase shift mask base 10 may also include a light-shielding film pattern 40 between the transparent substrate 20 and the phase shift film 30.

When the phase shift mask base 10 is provided with the light-shielding film pattern 40, the light-shielding film pattern 40 is arranged on the main surface of the transparent substrate 20. The light-shielding film pattern 40 has a function of blocking the transmission of exposure light.

The material for forming the light-shielding film pattern 40 is not particularly limited as long as it has a function of blocking the transmission of exposure light. For example, chromium-based materials can be cited. As a chromium material, it can be listed Examples include chromium (Cr), or chromium-based materials containing chromium (Cr), and at least one of carbon (C) and nitrogen (N). In addition, chromium-based materials containing chromium (Cr), and at least one of oxygen (O) and fluorine (F), or containing chromium (Cr), and carbon (C) and nitrogen (N) At least one of the chromium-based materials further includes at least one of oxygen (O) and fluorine (F). For example, as a material for forming the light-shielding film pattern 40, Cr, CrC, CrN, and CrCN can be cited.

The light-shielding film pattern 40 can be formed by patterning a light-shielding film formed by a sputtering method by etching.

In the portion where the phase shift film 30 and the light-shielding film pattern 40 are layered, the optical density to the exposure light is preferably 3 or more, more preferably 3.5 or more.

The optical density can be measured using a spectrophotometer, an OD (Optical Density) meter, or the like.

The light-shielding film pattern 40 may include a single film with a uniform composition, may include a plurality of films with different compositions, or may include a single film whose composition changes continuously in the thickness direction.

Furthermore, the phase shift mask substrate 10 may also be provided with a resist film on the phase shift film 30.

Next, the manufacturing method of the phase shift mask substrate 10 of this embodiment will be described. The phase shift mask substrate 10 is manufactured by performing the following preparation steps and phase shift film forming steps.

Hereinafter, each step will be described in detail.

1. Preparation steps

In the preparation step, first, the transparent substrate 20 is prepared. The material of the transparent substrate 20 is not particularly limited as long as it is transparent to the light used for exposure. For example, synthetic quartz glass, soda lime glass, and alkali-free glass can be cited.

In the case of manufacturing the phase shift mask substrate 10 with the light-shielding film pattern 40, thereafter, On the transparent substrate 20, a light-shielding film containing, for example, a chromium-based material is formed by a sputtering method. After that, a resist film pattern is formed on the light-shielding film, the resist film pattern is used as a mask, and the light-shielding film is etched to form a light-shielding film pattern 40. After that, the resist film pattern is peeled off.

2. Phase shift film formation steps

In the phase shift film forming step, a phase shift film 30 containing a chromium-based material is formed on the transparent substrate 20 by a sputtering method. Here, when the light-shielding film pattern 40 is formed on the transparent substrate 20, the phase shift film 30 is formed so as to cover the light-shielding film pattern 40.

The phase shift film 30 is formed by forming a phase shift layer 31 on the main surface of the transparent substrate 20, forming a metal layer 33 on the phase shift layer 31, and forming a reflectance reducing layer 32 on the metal layer 33.

The film formation of the phase shift layer 31 is performed using a sputtering target containing chromium or chromium-based materials in a sputtering gas atmosphere. The sputtering gas atmosphere includes, for example, selected from helium, neon, argon, krypton and At least one inert gas from the group consisting of xenon, and at least one selected from the group consisting of oxygen, nitrogen, nitric oxide gas, nitrogen dioxide gas, carbon dioxide gas, hydrocarbon-based gas, and fluorine-based gas Mixed gas of active gas. Examples of hydrocarbon-based gases include methane gas, butane gas, propane gas, and styrene gas. As the sputtering target, in addition to chromium metal, chromium-based materials such as chromium oxide, chromium nitride, chromium oxynitride, and chromium oxycarbonitride can also be used.

Similarly, the film formation of the metal layer 33 is performed using a sputtering target containing chromium or chromium-based materials in a sputtering gas atmosphere. The sputtering gas atmosphere includes, for example, selected from helium, neon, argon, and krypton. At least one inert gas selected from the group consisting of gas and xenon, or including at least one inert gas selected from the group consisting of helium, neon, argon, krypton, and xenon, and containing selected from oxygen , Nitrogen, nitric oxide gas, nitrogen dioxide gas, carbon dioxide gas, hydrocarbon-based gas, fluorine-based gas mixture of at least one active gas body. Examples of hydrocarbon-based gases include methane gas, butane gas, propane gas, and styrene gas. As the sputtering target, in addition to chromium metal, chromium-based materials such as chromium oxide, chromium nitride, chromium oxynitride, and chromium oxycarbonitride can also be used.

Similarly, the formation of the reflectance reduction layer 32 is performed using a sputtering target containing chromium or chromium-based materials in a sputtering gas atmosphere. The sputtering gas atmosphere includes, for example, selected from helium, neon, and argon. At least one inert gas from the group consisting of krypton gas and xenon gas, and includes selected from the group consisting of oxygen, nitrogen, nitric oxide gas, nitrogen dioxide gas, carbon dioxide gas, hydrocarbon-based gas, and fluorine-based gas A mixture of at least one active gas. Examples of hydrocarbon-based gases include methane gas, butane gas, propane gas, and styrene gas. As the sputtering target, in addition to chromium metal, chromium-based materials such as chromium oxide, chromium nitride, chromium oxynitride, and chromium oxycarbonitride can also be used.

When the phase shift layer 31, the metal layer 33, and the reflectance reduction layer 32 are formed, the composition and thickness of each of the phase shift layer 31, the metal layer 33 and the reflectance reduction layer 32 are based on the transmittance and phase of the phase shift film 30 The difference has the above-mentioned specific optical characteristics, and the film surface reflectance of the phase shift film 30 and its variation range are adjusted in such a way that the above-mentioned specific physical properties are provided. The composition of each of the phase shift layer 31, the metal layer 33, and the reflectance reduction layer 32 can be controlled according to the composition and flow rate of the sputtering gas. The thickness of each of the phase shift layer 31, the metal layer 33, and the reflectance reduction layer 32 can be controlled according to the sputtering power, the sputtering time, and the like. In addition, when the sputtering device is a continuous sputtering device, the thickness of each of the phase shift layer 31, the metal layer 33, and the reflectance reduction layer 32 can also be controlled according to the conveying speed of the substrate.

When the phase shift layer 31 includes a single film with a uniform composition or a plurality of films, the above-mentioned film forming process is performed only once or multiple times without changing the composition and flow rate of the sputtering gas. When the phase shift layer 31 includes a plurality of films with different compositions, for each film forming process, the composition and flow rate of the sputtering gas are changed to perform the above film forming process multiple times. The phase shift layer 31 includes In the case of a single film whose composition changes continuously in the thickness direction, the above-mentioned film forming process is performed only once while changing the composition and flow rate of the sputtering gas. The same applies to the film formation of the metal layer 33 and the film formation of the reflectance reduction layer 32. In the case of multiple film forming processes, the sputtering power applied to the sputtering target can be reduced.

The phase shift layer 31, the metal layer 33, and the reflectance reduction layer 32 preferably use a continuous sputtering device, and continuously form a film without taking the transparent substrate 20 out of the device and exposing it to the atmosphere. By continuously forming a film without taking it out of the device, it can prevent unexpected surface oxidation or surface carbonization of each layer. Unexpected surface oxidation or surface carbonization of each layer changes the laser light used when drawing the resist film formed on the phase shift film 30 or transfers the phase shift film pattern to the substrate formed on the display device The reflectivity of the exposure light used in the resist film may change the etching rate of the oxidized part or the carbonized part.

Furthermore, in the case of manufacturing the phase shift mask substrate 10 provided with a resist film, secondly, a resist film is formed on the phase shift film.

Regarding the phase shift mask base 10 of the first embodiment, the phase shift film 30 containing a chromium-based material provided on the transparent substrate 20 has: a phase shift layer 31; a reflectance reduction layer 32; and a metal layer 33, which is provided on Between the phase shift layer 31 and the reflectance reduction layer 32, in the 350nm~436nm wavelength region, it has a higher extinction coefficient than that of the reflectance reduction layer 32; the transmittance of the phase shift film 30 to exposed light and The phase difference satisfies the specific optical characteristics required as the phase shift film 30, and the film surface reflectance of the phase shift film 30 is less than 15% in the wavelength region of 350 nm to 436 nm. Therefore, by using the phase shift mask substrate 10, it is possible to manufacture a phase shift mask having an excellent pattern cross-sectional shape and an excellent CD uniformity and a fine pattern formed.

Furthermore, regarding the phase shift mask base 10 of the first embodiment, the phase shift film 30 containing a chromium-based material provided on the transparent substrate 20 has: a phase shift layer 31; a reflectance reduction layer 32; and a metal layer 33. It is arranged between the phase shift layer 31 and the reflectance reduction layer 32, and has a chromium content higher than that of the reflectance reduction layer 32; the transmittance and phase difference of the phase shift film 30 to the exposed light It satisfies the specific optical characteristics required as the phase shift film 30, and the reflectance of the film surface of the phase shift film 30 is less than 15% in the wavelength region of 350 nm to 436 nm. Therefore, by using the phase shift mask substrate 10, it is possible to manufacture a phase shift mask having an excellent pattern cross-sectional shape and an excellent CD uniformity and a fine pattern formed.

In addition, regarding the phase shift mask substrate 10 of the first embodiment, the back surface reflectance of the phase shift film is 20% or less in the wavelength region of 365 to 436 nm. Therefore, the influence of reflection on the exposure device side can be suppressed, so a phase shift mask that can perform high-precision pattern transfer can be manufactured.

Implementation form 2.

In the second embodiment, the manufacturing method of the phase shift mask will be described. The phase shift mask substrate is manufactured by performing the following resist film pattern forming step and phase shift film pattern forming step.

Hereinafter, each step will be described in detail.

1. Resist film pattern formation step

In the resist film pattern forming step, first, a resist film is formed on the phase shift film 30 of the phase shift mask substrate 10 of the first embodiment. However, when the phase shift mask base 10 is provided with a resist film on the phase shift film 30, the resist film is not formed. The resist film material used is not particularly limited. As long as it is sensitive to laser light having any wavelength selected from the wavelength range of 350 nm to 436 nm below. In addition, the resist film may be either a positive type or a negative type.

Thereafter, using laser light having any wavelength selected from the wavelength region of 350 nm to 436 nm, a specific pattern is drawn on the resist film. As the pattern drawn on the resist film, a line and gap pattern or a hole pattern can be cited.

Thereafter, the resist film is developed with a specific developer, and the resist film is formed on the phase shift film 30 Etchant film pattern.

2. Phase shift film pattern formation steps

In the phase shift film pattern forming step, first, the resist film pattern is used as a mask and the phase shift film 30 is etched to form the phase shift film pattern. Each of the phase shift layer 31, the metal layer 33, and the reflectance reduction layer 32 constituting the phase shift film 30 is formed of a chromium-based material containing chromium (Cr). Therefore, the phase shift layer 31, the metal layer 33, and the reflectance reduction layer 32 can be etched by the same etching medium (etching solution, etching gas). The etching medium (etching solution, etching gas) for etching the phase shift film 30 is not particularly limited as long as it can selectively etch the phase shift film 30. Specifically, examples include an etching solution containing cerium ammonium nitrate and perchloric acid, or an etching gas containing a mixed gas of chlorine and oxygen.

After that, a resist stripping solution is used or ashing is used to strip the resist film pattern.

According to the manufacturing method of the phase shift mask of the second embodiment, it is possible to manufacture a phase shift mask with excellent pattern cross-sectional shape and excellent CD uniformity, and with fine patterns formed.

Implementation mode 3.

In Embodiment 3, a method of manufacturing the display device will be described. The display device is manufactured by performing the following photomask placement step and pattern transfer step.

Hereinafter, each step will be described in detail.

1. Placement steps

In the placing step, the phase shift mask manufactured in Embodiment 2 is placed on the mask stage of the exposure apparatus. Here, the phase shift mask is arranged to face the resist film formed on the substrate of the display device through the projection optical system of the exposure device.

2. Pattern transfer steps

In the pattern transfer step, the phase shift mask is irradiated with exposure light, and the phase shift film pattern is transferred to the resist film formed on the substrate of the display device. The light for exposure includes composite light of multiple wavelengths selected from the wavelength region of 313nm~436nm, or monochromatic light selected by cutting off a certain wavelength region from the wavelength region of 313nm~436nm using a filter or the like. For example, the exposure light includes composite light of i-line, h-line, and g-line, or mixed light of j-line, i-line, h-line, and g-line, or monochromatic light of i-line. If the composite light is used as the light for exposure, the intensity of the light for exposure can be increased and the productivity can be increased, so the manufacturing cost of the display device can be reduced.

Furthermore, since it is a phase shift mask whose back reflectance of the phase shift film is 20% or less in the wavelength region of 365 to 436 nm, the influence of reflection on the exposure device side can be suppressed, and it can affect the substrate formed on the display device. The resist film performs high-precision pattern transfer.

According to the manufacturing method of the display device of the third embodiment, a high-resolution, high-definition display device can be manufactured.

[Example]

Hereinafter, the present invention will be described in more detail based on Examples and Comparative Examples. Furthermore, the following embodiment is an example of the present invention and does not limit the present invention.

The phase shift mask base of Examples 1 to 3 and Comparative Example 1 includes a transparent substrate and a phase shift film containing a chromium-based material disposed on the transparent substrate. As the transparent substrate, a synthetic quartz glass substrate with a size of 800 mm×920 mm and a thickness of 10 mm was used.

Fig. 3 shows the reflectance spectrum of the phase shift film of the phase shift mask substrate in Examples 1, 2, 3 and Comparative Example 1, and Fig. 4 shows the phase shift in Examples 1, 2, 3 and Comparative Example 1. The back reflectance spectrum of the phase shift film of the mask substrate. FIG. 5 is a graph showing the composition analysis result in the depth direction of the phase shift film of the phase shift mask substrate in Example 1. FIG. FIG. 6 is a graph showing the composition analysis result of the phase shift film of the phase shift mask substrate in Example 2 in the depth direction. Figure 7 shows the A graph showing the composition analysis results of the phase shift film in the depth direction of the phase shift mask substrate.

Hereinafter, Examples 1 to 3 and Comparative Example 1 will be described in detail.

Example 1.

The phase shift film in the phase shift mask base of Example 1 includes a phase shift layer, a metal layer, and a reflectance reduction layer sequentially arranged from the transparent substrate side, and further, at the interface between the phase shift layer and the metal layer, the metal layer A composition gradient region is formed at the interface with the reflectance reduction layer (refer to FIG. 5).

The phase shift mask substrate of Example 1 is manufactured by the following method.

First, prepare a synthetic quartz glass substrate as a transparent substrate. The two main surfaces of the transparent substrate are mirror-polished. The two main surfaces of the transparent substrates prepared in Examples 2, 3 and Comparative Example 1 were also mirror-polished in the same manner.

Next, the transparent substrate is loaded into a continuous sputtering device. A sputtering chamber is provided in the continuous sputtering device.

Secondly, apply a sputtering power of 2.7kW to the chromium target arranged in the sputtering chamber, while introducing the mixed gas of Ar gas, N ₂ gas, CO ₂ gas and O ₂ gas into the sputtering chamber, with a rate of 200 mm/min. Transport transparent substrates at high speed. Here, the mixed gas system is introduced into the sputtering chamber so that Ar becomes 35 sccm, N ₂ becomes 35 sccm, CO ₂ becomes 13 sccm, and O ₂ becomes 10 sccm. When the transparent substrate passes near the chromium target, a phase shift layer including a chromium-based material (CrCON) containing Cr, C, O, and N is formed on the transparent substrate.

Next, apply a sputtering power of 0.6kW to the chromium target, while introducing a mixed gas of Ar gas and CH ₄ gas (a mixed gas containing CH ₄ gas at a concentration of 4% in the Ar gas) into the sputtering chamber, and a side of 400mm /min speed to transport transparent substrates. When the transparent substrate passes near the chromium target, a metal layer including a chromium-based material (CrC) containing Cr and C is formed on the phase shift layer.

Next, a sputtering power of 3.3kW is applied to the chromium target, while introducing a mixed gas of Ar gas, N ₂ gas, CO ₂ gas and O ₂ gas into the sputtering chamber, the transparent substrate is transported at a speed of 400 mm/min. When the transparent substrate passes near the chromium target, a reflectance reduction layer including a chromium-based material (CrCON) containing Cr, C, O, and N is formed on the metal layer. Here, the mixed gas system is introduced into the sputtering chamber so that Ar becomes 35 sccm, N ₂ becomes 35 sccm, CO ₂ becomes 13 sccm, and O ₂ becomes 9 sccm.

Secondly, the transparent substrate on which the phase shift film including the phase shift layer, the metal layer and the reflectance reduction layer is formed is taken out from the continuous sputtering device and washed.

Furthermore, the formation of the phase shift layer, the formation of the metal layer, and the formation of the reflectance reduction layer are performed without taking the transparent substrate out of the continuous sputtering device and causing it to be exposed to the atmosphere. Continuously in a continuous sputtering device.

Since the phase shift film including the phase shift layer, the metal layer, and the reflectance reduction layer of Example 1 was formed in a continuous sputtering device, the interface between the phase shift layer and the metal layer, the metal layer and the reflectance reduction layer The interface is formed with a composition gradient region where the elements constituting each layer continuously form a composition gradient.

Regarding the phase shift film of Example 1, the result of measuring the composition in the depth direction by X-ray photoelectron spectroscopy (ESCA) is shown in FIG. 5.

The phase shift layer contains chromium-based materials containing chromium (Cr), oxygen (O), nitrogen (N) and carbon (C). The average content of each element is Cr: 49.8 atomic %, O: 40.0 atomic %, and N: 8.2 atomic %, C: 2.0 atomic %. In addition, the metal layer includes a chromium-based material containing chromium (Cr), carbon (C), and oxygen (O), and the average content of each element is Cr: 69.9 atomic %, C: 22.7 atomic %, and O: 7.4 atomic %. Furthermore, the reflectance reduction layer includes a chromium-based material containing chromium (Cr), oxygen (O), nitrogen (N), and carbon (C), and the average content of each element is Cr: 48.5 atomic %, O: 47.4 atomic% , N: 3.7 at%, C: 0.4 at%. In addition, between the phase shift layer and the metal layer, and between the metal layer and the reflectance reduction layer, there is a composition gradient region in which each element continuously decreases or increases.

In addition, the bonding state (chemical state) of the elements was evaluated from the spectra of Cr, O, and N in each layer. As a result, it was confirmed that the phase shift layer mainly contained chromium nitride (CrN), and further, chromium oxide III (Cr ₂ O ₃ ) was present.

In addition, it was confirmed that the bonding state (chemical state) of the elements constituting the metal layer mainly contained chromium (Cr), and further, chromium oxide III (Cr ₂ O ₃ ) was present.

In addition, it can be confirmed that the bonding state (chemical state) of the elements constituting the reflectance reduction layer mainly includes chromium oxide III (Cr ₂ O ₃ ), and there are chromium nitride (CrN) and chromium nitride (Cr ₂ N). ).

The phase shift film has a transmittance of 4.9% to 365nm light and a phase difference of 187° through the above three-layer structure.

In addition, the transmittance and phase difference were measured using MPM-100 (trade name) manufactured by Lasertec. In Examples 2, 3 and Comparative Example 1, the same measurement was performed.

Curve a in FIG. 3 represents the reflectance spectrum of the phase shift film of the phase shift mask substrate of Example 1. Curve a in FIG. 4 represents the back reflectance spectrum of the phase shift film of the phase shift mask substrate of Example 1.

As can be seen from Figure 3, regarding the phase shift film, the reflectance of the film surface is 13.3% at a wavelength of 313nm, 9.6% at 350nm, 8.3% at a wavelength of 365nm, and 7.1 at a wavelength of 405nm %, at a wavelength of 413nm, 7.3%, at a wavelength of 436nm, 8.1%. In addition, regarding the phase shift film, the variation range of the reflectance of the film surface is 2.5% in the 350nm~436nm wavelength region, 1.2% in the 365nm~436nm wavelength region, and 313nm~436nm in the wavelength region 6.2%.

As can be seen from Figure 4, for the phase shift film, the back surface reflectance is 9.7% at a wavelength of 313nm, 8.8% at 350nm, 9.0% at a wavelength of 365nm, and 12.3% at a wavelength of 405nm , At a wavelength of 413nm, 13.2%, at a wavelength of 436nm Down, 16.1%. In addition, regarding the phase shift film, the variation range of the reflectance of the film surface is 7.3% in the wavelength region of 350nm~436nm, 7.1% in the wavelength region of 365nm~436nm, and in the wavelength region of 313nm~436nm, it is 7.3%.

In addition, the film surface reflectance and the back reflectance were measured using SolidSpec-3700 (trade name) manufactured by Shimadzu Corporation. In Examples 2, 3 and Comparative Example 1, the same measurement was performed.

Using the above-mentioned phase shift mask substrate, the phase shift mask is manufactured by the following method.

First, a resist film containing a novolak-based positive photoresist is formed on the phase shift film of the aforementioned phase shift mask substrate.

Thereafter, a laser plotter is used to draw a specific pattern on the resist film using laser light with a wavelength of 413 nm.

After that, the resist film is developed with a specific developer to form a resist film pattern on the phase shift film.

After that, the resist film pattern is used as a mask and the phase shift film is etched to form a phase shift film pattern. Each of the phase shift layer, the metal layer, and the reflectance reduction layer constituting the phase shift film is formed of a chromium-based material containing chromium (Cr). Therefore, the phase shift layer, the metal layer, and the reflectance reduction layer can be etched by the same etching solution. Here, as an etching solution for etching the phase shift film, an etching solution containing cerium ammonium nitrate and perchloric acid is used.

After that, a resist stripping solution was used to strip the resist film pattern.

The cross section of the phase shift film pattern of the phase shift mask manufactured by using the above phase shift mask substrate has some erosion in the metal layer located in the center of the film thickness direction of the phase shift film pattern, but it does not affect the characteristics of the mask. The extent of the impact.

In addition, the cross-section of the phase shift film pattern of the phase shift mask was performed using an electron microscope (JEOL JSM7401F (trade name) manufactured by Co., Ltd. for observation. In Examples 2, 3 and Comparative Example 1, the same measurement was performed.

The CD deviation of the phase shift film pattern of the phase shift mask manufactured using the above phase shift mask substrate is 70 nm, which is relatively good. The CD deviation is the deviation width from the target line and gap pattern (the width of the line pattern: 2.0 μm, the width of the gap pattern: 2.0 μm).

Furthermore, the CD deviation of the phase shift film pattern of the phase shift mask was measured using SIR8000 manufactured by Seiko Instruments Technology. In Example 2 and Comparative Example 1, the same measurement was performed.

Since the above-mentioned phase shift mask has excellent pattern cross-sectional shape and excellent CD uniformity, and the film surface reflectivity of the phase shift film pattern to the exposure light is low, the use of the above-mentioned phase shift mask can produce high resolution , High-definition display device.

Example 2.

The phase shift film in the phase shift mask base of Example 2 includes a phase shift layer, a metal layer, and a reflectance reduction layer arranged in order from the transparent substrate side (refer to FIG. 6).

Except that the reflectance reducing layer constituting the phase shift mask substrate of Example 2 was formed under the following film forming conditions, the phase shift mask substrate was manufactured in the same manner as in Example 1. Regarding the reflectance reduction layer, a sputtering power of 2.15 kW was applied to the chromium target, while introducing a mixed gas of Ar gas, N ₂ gas, and O ₂ gas into the sputtering chamber, the transparent substrate was transported at a speed of 200 mm/min. When the transparent substrate passes near the chromium target, a reflectance reduction layer containing CrON is formed on the metal layer. Here, the mixed gas system is introduced into the sputtering chamber so that Ar becomes 35 sccm, N ₂ becomes 35 sccm, and O ₂ becomes 22 sccm.

Regarding the phase shift film of Example 2, the result of measuring the composition in the depth direction by X-ray photoelectron spectroscopy (ESCA) is shown in FIG. 6.

The phase shift layer contains chromium-based materials containing chromium (Cr), oxygen (O), nitrogen (N) and carbon (C). The average content of each element is Cr: 50.6 atomic %, O: 39.5 atomic %, and N: 8.3 at%, C: 1.6 at%. In addition, the metal layer includes a chromium-based material containing chromium (Cr), carbon (C), and oxygen (O), and the average content of each element is Cr: 69.2 atomic %, C: 22.8 atomic %, and O: 8.0 atomic %. Furthermore, the reflectance reduction layer 32 includes a chromium-based material containing chromium (Cr), oxygen (O), and nitrogen (N), and the average content of each element is Cr: 46.6 atomic %, O: 51.5 atomic %, and N: 1.7 At %, C: 0.2 at %. In addition, between the phase shift layer and the metal layer, and between the metal layer and the reflectance reduction layer, there is a composition gradient region in which each element continuously decreases or increases.

In addition, the bonding state (chemical state) of the elements was evaluated by the Cr, O, and N spectra of each layer of the phase shift layer, the metal layer, and the reflectance reduction layer. The result was that the bonding state (chemical state) and the implementation Example 1 is the same.

Also, as can be seen from Figures 5 and 6, the reflectance reduction layer of Example 2 has an oxygen (O) content increased by 4.1 atomic% compared to the reflectance reduction layer of Example 1. On the other hand, chromium (Cr The content rate of) is reduced by 1.9 atomic %. In this way, since the content of oxygen (O) is higher than that of the reflectance reducing layer of Example 1, the phase shift film of Example 2 is more excellent in terms of adhesion to the resist film.

The phase shift film has a transmittance of 5.2% to 365nm light and a phase difference of 183° through the above three-layer structure.

The curve b in FIG. 3 represents the reflectance spectrum of the phase shift film of the phase shift mask substrate of Example 2. The curve b in FIG. 4 represents the back reflectance spectrum of the phase shift film of the phase shift mask substrate of Example 2.

As can be seen from Figure 3, regarding the phase shift film, the reflectance of the film surface is 8.8% at a wavelength of 313nm, 7.5% at 350nm, and 8.1% at a wavelength of 365nm, at 405nm It is 10.6% at a wavelength of 413nm, 11.1% at a wavelength of 413nm, and 12.4% at a wavelength of 436nm. Also, regarding the phase shift film, the variation range of the reflectance of the film surface is 4.8% in the wavelength region of 350nm~436nm, 4.3% in the wavelength region of 365nm~436nm, and in the wavelength region of 313nm~436nm, it is 4.9%.

As can be seen from Figure 4, with regard to the phase shift film, the back reflectivity is 8.7% at a wavelength of 313nm, 8.9% at 350nm, 10.1% at a wavelength of 365nm, and 15.0% at a wavelength of 405nm , At a wavelength of 413nm, 16.0%, at a wavelength of 436nm, 18.1%. In addition, regarding the phase shift film, the variation range of the reflectance of the film surface is 9.2% in the wavelength region of 350nm~436nm, 8.0% in the wavelength region of 365nm~436nm, and in the wavelength region of 313nm~436nm, it is 9.7%.

In this way, the phase shift film of Example 1 is more excellent from the viewpoint of film surface reflectance.

Using the above-mentioned phase shift mask substrate, a phase shift mask was manufactured by the same method as in Example 1.

The cross section of the phase shift film pattern of the phase shift mask manufactured by using the above phase shift mask substrate is vertical, and no corrosion occurs in the metal layer.

The CD deviation of the phase shift film pattern of the phase shift mask manufactured using the above phase shift mask substrate is 60 nm, which is relatively good.

In this way, comparing the CD deviation of the phase shift film pattern of Example 1 and Example 2 formed by using the resist film pattern as a photomask, the CD deviation of Example 2 is less, and therefore the adhesion to the resist film From a standpoint, it is considered that the phase shift film of Example 2 is more excellent.

Since the above-mentioned phase shift mask has excellent pattern cross-sectional shape and excellent CD uniformity, and the film surface reflectivity of the phase shift film pattern to the exposure light is low, the use of the above-mentioned phase shift mask can produce high resolution , High-definition display device.

Example 3

The phase shift film in the phase shift mask base of Example 3 includes a phase shift layer, a metal layer, and a reflectance reduction layer arranged in order from the transparent substrate side (refer to FIG. 7).

Each layer of the phase shift layer, the metal layer, and the reflectance reduction layer in the phase shift mask substrate of Example 3 was formed under the following film forming conditions.

Regarding the phase shift layer, as the mixed gas, Ar becomes 35 sccm, N ₂ becomes 35 sccm, CO ₂ becomes 100 sccm, and O ₂ becomes 35 sccm. The flow rate is introduced into the sputtering chamber, except that it is transparent in the same way as in Example 1. The film formed on the substrate includes a phase shift layer of chromium-based material (CrON) containing Cr, O and N.

Next, regarding the metal layer, a sputtering power of 0.5 kW was applied to the chromium target arranged in the sputtering chamber. Except for this, in the same manner as in Example 1, a film was formed on the phase shift layer containing a chromium-based material containing Cr and C ( CrC) metal layer.

Next, as for the reflectance reduction layer, the mixed gas was introduced into the sputtering chamber so that the flow rate of Ar was 35 sccm, N _{2 was} 35 sccm, CO _{2 was} 100 sccm, and O _{2 was} 35 sccm, except for that, the same as in Example 1 Form a film on the metal layer and include a chromium-based material (CrCO) containing Cr, O, and N reflectance reduction layer.

Regarding the phase shift film of Example 3, the result of measuring the composition in the depth direction by X-ray photoelectron spectroscopy (ESCA) is shown in FIG. 7.

The phase shift layer contains chromium-based materials containing chromium (Cr), oxygen (O), nitrogen (N) and carbon (C). The average content of each element is Cr: 45.5 atomic %, O: 53.8 atomic %, and N: 0.6 at%, C: 0.1 at%. In addition, the metal layer includes a chromium-based material containing chromium (Cr), carbon (C), and oxygen (O), and the average content of each element is Cr: 74.7 atomic%, C: 15.8 atomic%, O: 8.8 atomic%, N: 0.7 atomic %. Furthermore, the reflectance reduction layer 32 contains chromium (Cr), oxygen (O), nitrogen (N) and carbon For the chromium-based material of (C), the average content of each element is Cr: 44.4 at%, O: 55.0 at%, N: 0.5 at%, and C: 0.1 at%. In addition, between the phase shift layer and the metal layer, and between the metal layer and the reflectance reduction layer, there is a composition gradient region in which each element continuously decreases or increases.

In addition, the bonding state (chemical state) of the elements was evaluated from the spectra of Cr, O, and N in each layer. As a result, it was confirmed that the phase shift layer mainly contained chromium nitride (Cr ₂ N), and furthermore, chromium oxide III (Cr ₂ O ₃ ) and chromium oxide VI (CrO ₃ ) were present.

In addition, it was confirmed that the bonding state (chemical state) of the elements constituting the metal layer mainly contained chromium (Cr), and further, chromium oxide III (Cr ₂ O ₃ ) was present.

It was also confirmed that the bonding state (chemical state) of the elements constituting the reflectance reduction layer mainly contained chromium oxide III (Cr ₂ O ₃ ).

The phase shift film has a transmittance of 4.9% to 365nm light and a phase difference of 187° through the above three-layer structure.

The curve c in FIG. 3 represents the reflectance spectrum of the phase shift film of the phase shift mask substrate of Example 3. The curve c in FIG. 4 represents the back surface reflectance spectrum of the phase shift film of the phase shift mask substrate of Example 3.

As can be seen from Figure 3, regarding the phase shift film, the film surface reflectance is 21% at a wavelength of 313nm, 14.7% at 350nm, 12.8% at a wavelength of 365nm, and 10.2 at a wavelength of 405nm %, at a wavelength of 413nm, 9.8%, at a wavelength of 436nm, 9.0%. In addition, regarding the phase shift film, the variation range of the reflectance of the film surface is 5.7% in the 350nm~436nm wavelength region, 3.8% in the 365nm~436nm wavelength region, and 313nm~436nm in the wavelength region 12.0%.

As can be seen from Figure 4, for the phase shift film, the back surface reflectivity is 7.5% at a wavelength of 313nm, 8.3% at 350nm, and 9.8% at a wavelength of 365nm, at 405nm At the wavelength of 413nm, it is 14.9%, at the wavelength of 413nm, it is 15.9%, and at the wavelength of 436nm, it is 18.2%. Also, regarding the phase shift film, the variation range of the reflectance of the film surface is 9.9% in the wavelength region of 350nm~436nm, 8.3% in the wavelength region of 365nm~436nm, and in the wavelength region of 313nm~436nm, it is 11.0%.

In addition, the film surface reflectance and the back reflectance were measured using SolidSpec-3700 (trade name) manufactured by Shimadzu Corporation.

In the same manner as the above-mentioned embodiment, the phase shift mask substrate of the third embodiment is used to manufacture a phase shift mask. The CD deviation of the phase shift film pattern of the obtained phase shift mask is 65 nm, which is relatively good. The CD deviation is the deviation width from the target line and gap pattern (the width of the line pattern: 2.0 μm, the width of the gap pattern: 2.0 μm).

Since the above-mentioned phase shift mask has excellent pattern cross-sectional shape and excellent CD uniformity, and the film surface reflectivity of the phase shift film pattern to the exposure light is low, the use of the above-mentioned phase shift mask can produce high resolution , High-definition display device.

Comparative example 1.

The phase shift film in the phase shift mask substrate of Comparative Example 1 only includes the phase shift layer (CrOCN, film thickness 122 nm). The phase shift mask substrate of Comparative Example 1 is different from the phase shift mask substrate of the foregoing embodiment in that the phase shift film does not have a metal layer and a reflectance reduction layer.

The phase shift layer in the phase shift mask substrate of Comparative Example 1 was formed under the following film forming conditions.

Regarding the phase shift layer, a sputtering power of 3.5kW is applied to the chromium target arranged in the sputtering chamber, and a mixture of Ar gas, N ₂ gas and CO ₂ gas is introduced into the sputtering chamber at a speed of 200 mm/min. Transport transparent substrates. When the transparent substrate passes near the chromium target, a 122nm phase shift layer containing CrOCN is formed on the main surface of the transparent substrate. Here, the mixed gas system is introduced into the sputtering chamber so that Ar becomes 46 sccm, N ₂ becomes 32 sccm, and CO ₂ becomes 18.5 sccm.

Regarding the phase shift film of Comparative Example 1, the composition in the depth direction was measured by X-ray photoelectron spectroscopy (ESCA). The phase shift film is uniform in the depth direction, Cr: 44 at%, C: 8 at%, O: 30 at%, and N: 18 at%.

The phase shift film has a transmittance of 4.5% to 365nm light and a phase difference of 181° through the above-mentioned one-layer structure.

The curve d in FIG. 3 represents the reflectance spectrum of the phase shift film of the phase shift mask substrate of Comparative Example 1. The curve d in FIG. 4 represents the back reflectance spectrum of the phase shift film of the phase shift mask substrate of Comparative Example 1.

As can be seen from Figure 3, regarding the phase shift film, the reflectance of the film surface is 21.0% at a wavelength of 313nm, 23.9% at 350nm, 24.0% at a wavelength of 365nm, and 25.1 at a wavelength of 405nm %, at a wavelength of 413nm, 25.3%, at a wavelength of 436nm, 26.0%. In addition, regarding the phase shift film, the variation range of the reflectance of the film surface is 2.1% in the wavelength region of 350nm~436nm, 2.0% in the wavelength region of 365nm~436nm, and in the wavelength region of 313nm~436nm, it is 12.0%.

As can be seen from Figure 4, for the phase shift film, the back reflectance is 7.5% at a wavelength of 313nm, 17.1% at 350nm, 17.9% at a wavelength of 365nm, and 19.9% at a wavelength of 405nm , At a wavelength of 413nm, 20.2%, at a wavelength of 436nm, 20.3%. In addition, regarding the phase shift film, the variation range of the reflectance of the film surface is 3.2% in the wavelength region of 350nm~436nm, 2.4% in the wavelength region of 365nm~436nm, and in the wavelength region of 313nm~436nm, it is 11.0%.

Using the above-mentioned phase shift mask substrate, a phase shift mask was manufactured by the same method as in Example 1.

The cross section of the phase shift film pattern of the phase shift mask manufactured by using the above phase shift mask substrate is vertical.

The CD deviation of the phase shift film pattern of the phase shift mask manufactured by using the above-mentioned phase shift mask substrate is 90 nm, which does not reach the level required for the manufacture of the phase shift mask for high-resolution, high-definition display devices.

Although the above-mentioned phase shift mask has an excellent cross-sectional shape of the pattern, the CD deviation is large, and the film surface reflectivity of the phase shift film pattern to the exposure light is relatively high. Therefore, the use of the above-mentioned phase shift mask cannot produce high resolution , High-definition display device.

As described above, the present invention will be described in detail based on the embodiments and examples, but the present invention is not limited to this. It is obvious that as long as the person has general knowledge in the field, modifications or improvements within the technical idea of the present invention can be made. For example, in the embodiment, the reflectance reduction layer is used as the first functional layer and the phase shift layer is used as the second functional layer. However, when the specific optical characteristics are satisfied, the phase shift layer may be used as the first functional layer. , With a reflectance reduction layer as the second functional layer.

10‧‧‧Phase shift mask base

20‧‧‧Transparent substrate

30‧‧‧Phase Shift Film

31‧‧‧Phase shift layer

32‧‧‧Reflectance reduction layer

33‧‧‧Metal layer

Claims (10)

A phase shift mask substrate, characterized in that it is provided with a phase shift film containing a chromium-based material on a transparent substrate, and the phase shift film has a first functional layer constituting its lower layer and a second function constituting its upper layer Layer and an intermediate layer arranged between the first functional layer and the second functional layer, the first functional layer and the second functional layer include chromium-based materials containing chromium, oxygen and nitrogen, and the chromium is 30 to 70 Atomic %, oxygen is 20-60 atomic%, nitrogen is 0.4-30 atomic%, the content of nitrogen contained in the first functional layer is the same as or more than the content of nitrogen contained in the second functional layer The content of oxygen contained in the second functional layer is greater than the content of oxygen contained in the first functional layer. The intermediate layer contains chromium and carbon. The content of chromium is 55 to 90 atomic %. The content rate is 10~45 atomic %, and the content rate of chromium contained in the intermediate layer is higher than the content rate of chromium contained in the first functional layer and the second functional layer. Such as the phase shift mask substrate of claim 1, wherein the first functional layer has the function of mainly adjusting the transmittance and phase difference of the exposed light, and the second functional layer has the function of reducing the light incident from the side of the phase shift film For the function of reflectivity, the film thickness of the first functional layer is thicker than the film thickness of the second functional layer. The phase shift mask substrate of claim 1 or 2, wherein the first functional layer includes chromium nitride or chromium nitride, and the second functional layer includes chromium oxide III formed by bonding chromium and oxygen. The phase shift mask substrate of claim 1 or 2, wherein the intermediate layer further includes a chromium-based material containing oxygen, and the first functional layer, the intermediate layer, and the second functional layer include chromium oxide III. The phase shift mask substrate of claim 1 or 2, wherein the surface reflectivity of the phase shift film to light incident from the side of the phase shift film is 15% or less in the wavelength region of 350 to 436 nm. The phase shift mask substrate of claim 1 or 2, wherein the back reflectivity of the phase shift film to the light incident from the transparent substrate side is 22.5% or less in the wavelength region of 313 to 436 nm. The phase shift mask base of claim 1 or 2, wherein a light-shielding film pattern is provided between the transparent substrate and the phase shift film. A method for manufacturing a phase shift mask, which is characterized by having the following steps: forming a resist film on the phase shift film of the phase shift mask substrate according to any one of claims 1 to 7, and A step of forming a resist film pattern by drawing processing and developing processing using laser light having any wavelength selected from the wavelength region of 350nm to 436nm; and using the resist film pattern as a photomask And etching the phase shift film to form a phase shift film pattern on the transparent substrate. A method for manufacturing a display device is characterized by the following steps: The step of placing the phase shift mask manufactured by the manufacturing method of the phase shift mask according to claim 8 on the mask stage of the exposure device; and irradiating the phase shift mask with exposure light, and patterning the phase shift film The step of transferring on the resist film formed on the substrate of the display device. The method for manufacturing a display device according to claim 9, wherein the light for the exposure includes a composite light of light of a plurality of wavelengths selected from a wavelength region of 313 nm to 436 nm.

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