JP6983641B2 - A phase shift mask blank for manufacturing a display device, a method for manufacturing a phase shift mask for manufacturing a display device, and a method for manufacturing a display device. - Google Patents

Description

The present invention relates to a phase shift mask blank for manufacturing a display device, a method for manufacturing a phase shift mask for manufacturing a display device, and a method for manufacturing a display device.

When manufacturing a liquid crystal display device or an organic EL display device, a semiconductor element such as a transistor is formed by laminating a plurality of conductive films or insulating films having necessary patterns. At that time, a photolithography process is often used for patterning the individual films to be laminated. For example, some thin film transistors and LSIs used in these display devices have a structure in which a contact hole is formed in an insulating layer by a photolithography process and the upper layer pattern and the lower layer pattern are electrically connected. Recently, in such a display device, there is an increasing need to display a bright and fine image with a sufficient operating speed and to reduce power consumption. In order to meet these demands, it is required that the constituent elements of the display device be miniaturized and highly integrated. For example, it is desired to reduce the diameter of the contact hole from 3 μm to 2.5 μm, 2 μm, 1.8 μm, and 1.5 μm. Further, for example, it is desired to reduce the pitch width of the line and space pattern from 3 μm to 2.5 μm, 2 μm, 1.8 μm, and 1.5 μm.

Against this background, there is a demand for photomasks for manufacturing display devices that can handle line-and-space patterns and miniaturization of contact holes.

In order to realize the miniaturization of line-and-space patterns and contact holes, the resolution limit of the exposure machine for manufacturing display devices is 3 μm in the conventional photomask, so there is no sufficient process likelihood (Process Margin). Products with the minimum line width close to the resolution limit must be produced. Therefore, there is a problem that the defect rate of the display device becomes high.

For example, when a photomask having a hole pattern for forming a contact hole is used and it is considered to transfer this to a transfer target, if the hole pattern has a diameter of more than 3 μm, it is transferred with a conventional photomask. I was able to. However, it has been very difficult to transfer a hole pattern having a diameter of 3 μm or less, particularly a hole pattern having a diameter of 2.5 μm or less. In order to transfer a hole pattern having a diameter of 2.5 μm or less, it is conceivable to switch to an exposure machine having a high NA, for example, but a large investment is required.

Therefore, in order to improve the resolution and cope with the miniaturization of line-and-space patterns and contact holes, a phase shift mask is attracting attention as a photomask for manufacturing a display device.

For example, Patent Document 1 proposes a phase shift mask blank for a display device provided with a phase shift film having a structure in which two or more thin films are laminated on a transparent substrate. Each thin film constituting this phase shift film has a different composition from each other, but both are made of substances that can be etched by the same etching solution, and have different etching rates due to the different compositions. In Patent Document 1, the etching rate of each thin film constituting the phase shift film is adjusted so that the cross-sectional inclination of the edge portion of the phase shift film pattern is formed at a steep angle (to a steep slope) when the phase shift film is patterned. ing.
The phase shift film specifically described in Patent Document 1 is a chromium-based phase shift film having a structure in which three, five, or six layers of chromium carbonized nitride (CrCON) having different compositions are laminated. be.

Patent Document 2 describes a phase inversion blank mask for FPD in which a phase inversion film, a metal film used as an etching mask for the phase inversion film, and a resist film are sequentially laminated on a transparent substrate. Here, the phase inversion film is composed of, for example, one of MoSi, MoSiO, MoSiN, MoSiC, MoSiCO, MoSiON, MoSiCN, and MoSiCON, and the metal film (etching mask film) has an etching selectivity with the phase inversion film. It is described that the substance is composed of one of Cr, CrO, CrN, CrC, CrCO, CrON, CrCN and CrCON, for example.
In Patent Document 2, the phase inversion film has a transmittance of 1% to 40%, preferably 5% to 20%, and a transmittance of 10% or less with respect to the exposure light having a composite wavelength. It is stated that it is desirable to have a deviation. Further, it is described that the phase inversion film has a reflectance of 30% or less, preferably 15% or less, and preferably has a reflectance deviation of 10% or less with respect to the exposure light having a composite wavelength. (Here, the deviation means the difference between the maximum value and the minimum value among the values of the transmittance and the reflectance of the i-line, h-line, and g-line exposed light.)
However, Patent Document 2 does not describe an example in which a specific material for a phase inversion film and a metal film (etching mask film) for satisfying these optical characteristics is specified.

Such a phase shift mask receives exposure light of various wavelengths output from various exposure machines.
For example, in the case of a phase shift mask for manufacturing a display device, as an exposure machine used in the process of transferring a mask pattern, for example, peak intensities are applied to i-line (365 nm), h-line (405 nm) and g-line (436 nm), respectively. A light source (ultra-high pressure UV lamp) that outputs a composite light is known. For example, when the composite light is used as the exposure light when the mask pattern of the phase shift mask is transferred onto the main surface of the mother glass substrate whose size is increasing with the increase in size of the display device in recent years, the amount of light is reduced. It is possible to earn money and shorten the tact time.

Korean Registered Patent No. 1282040 Gazette Korean Registered Patent No. 1624995

First, in the phase shift mask for display devices and the phase shift mask blank, "the fluctuation range (change amount) of the transmittance in the range of wavelength 365 nm or more and 436 nm or less (appropriately referred to as predetermined transmittance wavelength dependence)". A small (for example, within 5.5%) phase shift film is basically very difficult to realize (Problem 1). The reason for this is that the composition and film thickness of each layer constituting the phase shift film are adjusted (priority is given to this) in order to satisfy the essential optical characteristics (phase difference, transmittance), and the transmittance of the phase shift film is adjusted accordingly. This is because the wavelength dependence is fixed, so that only the transmittance wavelength dependence cannot be independently and freely controlled (independently adjusted to a desired value). For these reasons, no actual measured values of transmittance and reflectance have been reported for specific examples in which the layer structure of the phase shift film and the material of each layer are specified.
Therefore, for the above-mentioned problem 1, it is desired to provide a new phase shift film having excellent transmittance wavelength dependence.

In addition to the above, in particular, in a phase shift mask and a phase shift mask blank for a display device of a high transmittance (for example, 15% or more, particularly 18% or more) type, the transmittance wavelength dependence is small (for example, 5. (Within 5%) There is a situation that it is extremely difficult to realize a phase shift film (Problem 2). The reasons for this are (1) the materials suitable for high transmittance are limited, (2) generally, the higher the transmittance, the larger the transmittance wavelength dependence tends to be, and (3) this. Due to the tendency, in order to reduce the transmittance wavelength dependence, it is necessary to greatly reduce the transmittance wavelength dependence, but this is basically difficult.

In a phase shift film having such a high transmittance, for example, a specific example having a transmittance wavelength dependence having a predetermined transmittance wavelength dependence of less than 5.5% has not been reported (Problem 3).

Secondly, the phase shift film used for the phase shift mask for the display device conventionally proposed in Patent Document 1 described above is laser drawing light used when patterning the resist film used for forming the phase shift film pattern. It is not designed in consideration of the influence of the reflection on the resist film. Therefore, the surface reflectance of the phase shift film with respect to the laser drawing light (usually one wavelength having a wavelength range of 350 nm to 436 nm) exceeds 20%. As a result, a standing wave is generated in the resist film, and the roughness of the edge portion of the resist film pattern deteriorates. Along with this, there is a problem that the roughness of the edge portion of the phase shift film pattern deteriorates.
In the above-mentioned Patent Document 2, it is described that the phase inversion film has a reflectance of 30% or less, preferably 15% or less with respect to exposure light having a composite wavelength, but a film for realizing this. No specific examples of the composition or membrane material have been reported.
The surface reflectance at the wavelength of the laser drawing light is ideally 10% or less, further 5% or less, but the surface reflectance should be 10% or less while satisfying various optical characteristics and the like. Is actually very difficult.
Specifically, in the case of a light-shielding film, it is only necessary to satisfy the light-shielding property (optical density), so it is relatively easy to provide an antireflection layer and add the characteristics of surface reflectance. On the other hand, in the case of a phase shift film, the phase difference and transmittance also fluctuate by providing an antireflection layer, so a film design that satisfies the phase difference and transmittance and also has the characteristics of surface reflectance. Is not easy to do. Therefore, it is not even easier to equip the phase shift film with the characteristics of surface reflectance while satisfying the transmittance wavelength dependence in addition to the phase difference and transmittance (Problem 4).
In addition, it is required to exceed the level of reflectance described in Patent Document 2 (for example, "15% or less"). Specifically, for example, no specific example has been reported in which the reflectance in the wavelength range of 365 nm or more and 436 nm or less is 10% or less, or the reflectance in the wavelength range of 350 nm or more and 436 nm or less is 15% or less.

Further, the phase shift film used for the phase shift mask for the display device conventionally proposed in the above-mentioned Patent Documents 1 and 2 is not designed in consideration of the back surface reflectance in the wavelength range of 365 nm or more and 436 nm or less.
Therefore, when the back surface reflectance is relatively low, there is a possibility that the pattern position shift due to thermal expansion due to heat absorption of the exposure light by the film.
Therefore, it is not easy for the phase shift film to have the characteristics of backside reflectance while satisfying a predetermined transmittance wavelength dependence in addition to the phase difference and transmittance (Problem 5).

The first object of the present invention is to provide a new phase shift film having excellent transmittance wavelength dependence for the above-mentioned problem 1.
A second object of the present invention is to provide a new phase shift film which is excellent in transmittance wavelength dependence and also excellent in other characteristics with respect to the above-mentioned problem 1.
A third object of the present invention is to provide a new phase shift film having excellent transmittance wavelength dependence even with high transmittance, in response to the above-mentioned problems 2 and 3.
A fourth object of the present invention is to provide a new phase shift film having exceptionally excellent transmittance wavelength dependence for the above-mentioned problems 1, 2 and 3.
A fifth object of the present invention is to provide a new phase shift film having excellent transmittance wavelength dependence and excellent surface reflectance characteristics in response to the above-mentioned problem 4.
A sixth object of the present invention is to provide a new phase shift film which is excellent in transmittance wavelength dependence and also excellent backside reflectance characteristics in response to the above-mentioned problem 5.
The present invention comprises a phase shift mask blank for manufacturing a display device provided with the phase shift film according to the present invention, a method for manufacturing a phase shift mask using the phase shift mask blank, and a display using the phase shift mask. The purpose is to provide a method for manufacturing the device.

The present inventor has carried out diligent research and development to provide a new phase shift film having excellent transmittance wavelength dependence.
First, the ZrSi-based material containing Zr and Si is for high transmittance having a transmittance of 15% or more in the wavelength range of the exposed light (multiple wavelengths including i-line, h-line, and g-line). The present inventor has found that it is suitable as a material used for a phase shift film.
Further, it has been considered that it is relatively difficult for the phase shift film to reduce the wavelength dependence of the transmittance as the transmittance is increased. Specifically, even if various adjustments are made, for example, in a wavelength range of 365 nm or more and 436 nm or less (appropriately referred to as “predetermined wavelength range”), when the transmittance is usually about 20%, a predetermined wavelength It was thought that the transmittance wavelength dependence (fluctuation range of transmittance) in the range could be reduced only to about 10%.
Further, in the phase shift film, the "transmittance wavelength dependence in the wavelength range of 365 nm or more and 436 nm or less" (appropriately referred to as "predetermined transmittance wavelength dependence") is applied to ZrSi-based materials (for example, ZrSiON, ZrSiN, ZrSiO). In comparison, MoSi-based materials (for example, MoSiN, MoSiON, MoSiOCN) were considered to have better transmittance wavelength dependence.
Further, in the process of study, the present inventor adjusts the composition of ZrSi-based materials (for example, ZrSiON, ZrSiN, ZrSiO) to have high transmittance (for example, 16% and 20% at a wavelength of 365 nm). , 30%, 40% transmittance), the predetermined transmittance wavelength dependence tends to become larger and larger (for example, the predetermined transmittance wavelength dependence is 11%, 18%, 21%, 25). %, Will be). Due to this tendency, it was found that it is very difficult to reduce the predetermined transmittance wavelength dependence.

Furthermore, the present inventor has found that a ZrSi-based single-layer film (particularly, ZrSiON, ZrSiO, etc. containing oxygen (O)) has a problem that it is very difficult to control the in-plane distribution of transmittance. .. The reason for this is that the ZrSi-based single-layer film containing oxygen (O) has a characteristic that the transmittance changes sharply (the angle of the transmittance-wavelength curve becomes steep) in the wavelength range from 300 nm to 400 nm. It is thought that there is. At this time, when the film thickness of the ZrSi-based single-layer film containing oxygen (O) fluctuates, the transmittance-wavelength curve also moves to the short wavelength side or the long wavelength side, and the transmittance fluctuates. Therefore, it becomes difficult to control the in-plane distribution of the transmittance due to the in-plane variation in the film thickness of the ZrSi-based single-layer film containing oxygen (O).

Under the above circumstances, the present inventor has determined that the phase shift layer (for example, ZrSiON; the composition is adjusted for high transmittance) and the metal layer (for example, ZrSi; the content of Zr contained in the phase shift layer). By combining ZrSi), which has a higher Zr content and a higher total Zr and Si content than the total content of Zr and Si contained in the phase shift layer, surprisingly, contrary to the above general recognition, Even when the transmittance is high (for example, 15% or more, 16% or more, and further 18% or more) in a predetermined wavelength range (function 5), the predetermined transmittance wavelength dependence is regarded as the above general recognition. It was found that the relative size can be made relatively small (for example, within 5.5%) (function 1), that is, the requirements of both function 5 and function 1 can be satisfied. At this time, the content of Zr or the total content of Zr and Si is higher than the content of Zr contained in the metal layer (for example, ZrSi; the phase shift layer) or the total content of Zr and Si contained in the phase shift layer. It has been found that ZrSi), which has a large amount of zirconium, has an action / function capable of adjusting the predetermined transmission wavelength dependence of the phase shift layer (for example, ZrSiON) as a single layer. Specifically, the metal layer (for example, ZrSi) can reduce the predetermined transmittance wavelength dependence of the phase shift layer (for example, ZrSiON) as a single layer by a predetermined value (predetermined width) (for example, 10%) or more (for example, predetermined). It was found that the transmittance wavelength dependence of the transmittance can be reduced by 10% or more from a value of 15% or more to a value of 5.5% or less) (transmittance wavelength dependence reduction function).
High transmittance (for example, 15% or more, 16% or more, and even 18% or more) and low predetermined wavelength dependence (for example, within 5.5%) have very high resolution. Good for. The reason for this is that the amount of light having a wavelength other than 365 nm (405 nm, 436 nm) interfering with the light of 365 nm is reduced. Since the resolution is very good, it is possible to manufacture a display device having a fine pattern (for example, 1.8 μm or less).
Further, in the present invention, the transmittance and the reflectance in a predetermined wavelength range can be reduced in wavelength dependence as compared with the case of a single layer (the slope of the transmittance-wavelength curve becomes flat (the slope becomes small)). Even if the film thickness varies slightly in the plane (for example, in the central portion and the outer peripheral portion) in the film forming process, the in-plane distribution of the transmittance and the reflectance becomes very good. Therefore, it is possible to manufacture a display device having a small in-plane variation in the CD accuracy of a fine pattern.

Further, the present inventor mainly has a phase shift layer (for example, ZrSiON) for adjusting the transmittance and the phase difference with respect to the exposure light, and a metal layer (for the exposure light) having a function of adjusting the transmittance wavelength dependence with respect to the exposure light. A phase shift film having a predetermined transmittance wavelength dependence of less than 4.0% and an exceptionally excellent transmittance wavelength dependence in combination with a metal layer (for example, ZrSi) having a function of reducing the transmittance wavelength dependence. It was found that (Problem 3) can be realized.

Further, the present inventor has found that the above is the same even when the metal layer is replaced with a metal silicide-based material such as MoSi or TiSi, although the degree is different.

The present inventor has described the above as a phase shift layer (MoSiON) (for a normal transmittance having a transmittance of about 1% to 12% with respect to an exposure wavelength, and having a transmittance of 15% or more with respect to an exposure wavelength. When a combination of a metal layer (MoSi) and a metal layer (MoSi), a phase shift layer (TiSiON) (including normal transmittance to high transmittance), and a metal layer (TiSi) It was found that the same is true even when these are combined, although the degree is different.

As a result of further studies, the present inventor has a predetermined phase shift layer (for example, ZrSiON, MoSiON, TiSiON, etc.) and a predetermined metal layer (for example, ZrSi, etc.) in a phase shift film composed of two or more laminated films. By combining with MoSi, TiSi, etc. (in no particular order), the predetermined transmittance wavelength dependence can be made very small (for example, within 5.5%) (function 1), and the backside reflectance can be controlled. (Function 4) It was found.

Further, the present inventor has a phase shift film composed of three laminated films, in which a predetermined phase shift layer (for example, ZrSiON, MoSiON, TiSiON, etc.) and a predetermined metal layer (for example, ZrSi, MoSi) are sequentially formed from the substrate side. , TiSi, etc.) and a predetermined reflectance reducing layer (for example, ZrSiON, MoSiON, TiSiON, CrO, CrOCN, CrON, etc.) can reduce the predetermined transmittance wavelength dependence (function 1) (for example). It can be done within 5.5%), the surface reflectance can be reduced (function 2), the surface reflectance can be reduced (for example, 10% or less) (function 3), and the back surface reflectance can be controlled (function 4). ), It was found that all of them can be combined.

In the phase shift film composed of the above-mentioned two or more or three layers of laminated film, the phase shift film using a Cr-based material as the uppermost layer has good adhesion of the resist film formed on the phase shift film.

The present invention has the following configurations.
(Structure 1)
In a phase shift mask blank for manufacturing display devices
A transparent substrate and a phase shift film formed on the transparent substrate are provided.
The phase shift film is composed of two or more laminated films.
The phase shift film mainly includes a phase shift layer having a function of adjusting the transmittance and a phase difference with respect to exposure light, and a metal layer having a function of adjusting the transmittance wavelength dependence in the wavelength range of 365 nm or more and 436 nm or less. Have at least
The phase shift film has predetermined optical characteristics in terms of the transmittance and phase difference of the phase shift film with respect to the exposure light.
The phase shift layer is made of a material containing a metal, silicon, and one or more elements selected from nitrogen and oxygen.
The metal layer is made of a material composed of metal and silicon, or a material composed of metal and silicon, and at least one of carbon, fluorine, nitrogen, and oxygen.
The content of the metal contained in the metal layer is higher than the content of the metal contained in the phase shift layer, or the total content of the metal and silicon contained in the metal layer is contained in the phase shift layer. More than the total content of metal and silicon
The phase shift mask is a phase shift mask blank having a transmittance wavelength dependence of 5.5% or less in a wavelength range of 365 nm or more and 436 nm or less.
(Structure 2)
In a phase shift mask blank for manufacturing display devices
A transparent substrate and a phase shift film formed on the transparent substrate are provided.
The phase shift film is mainly a phase shift layer having a function of adjusting the transmittance and a phase difference with respect to the exposure light, and light incident on the upper side of the phase shift layer and incident from the surface side of the phase shift film. A function of adjusting the transmittance wavelength dependence in the wavelength range of 365 nm or more and 436 nm or less, which is arranged between the phase shift layer and the reflectance reducing layer, and a reflectance reducing layer having a function of reducing the transmittance with respect to the light. Has a metal layer to have
Due to the laminated structure of the phase shift layer, the metal layer and the reflectance reducing layer, the transmittance and phase difference of the phase shift film with respect to the exposure light have predetermined optical characteristics.
The phase shift layer is made of a material containing metal, silicon, and at least one of nitrogen and oxygen.
The metal layer is made of a material composed of metal and silicon, or a material composed of metal and silicon, and at least one of carbon, fluorine, nitrogen, and oxygen.
The content of the metal contained in the metal layer is higher than the content of the metal contained in the phase shift layer, or the total content of the metal and silicon contained in the metal layer is contained in the phase shift layer. More than the total content of metal and silicon
The phase shift mask is a phase shift mask blank having a transmittance wavelength dependence of 5.5% or less in a wavelength range of 365 nm or more and 436 nm or less.
(Structure 3)
The phase shift mask blank according to the configuration 1 or 2, wherein the phase shift film has a transmittance in the range of 1% or more and 50% or less at a wavelength of 365 nm.
(Structure 4)
The phase shift mask blank according to the configuration 1 or 2, wherein the phase shift film has a transmittance in the range of 15% or more and 50% or less at a wavelength of 365 nm.
(Structure 5)
The phase shift film has configurations 2 to 4 characterized in that the surface reflectance of the phase shift film with respect to light incident from the surface side of the phase shift film is 10% or less in the wavelength range of 365 nm to 436 nm. The phase shift mask blank described in any of.
(Structure 6)
The phase shift film has configurations 2 to 5 characterized in that the surface reflectance of the phase shift film with respect to light incident from the surface side of the phase shift film is 15% or less in the wavelength range of 350 nm to 436 nm. The phase shift mask blank described in any of.
(Structure 7)
The phase according to any one of configurations 1 to 6, wherein the back surface reflectance of the phase shift film with respect to light incident from the back surface side of the transparent substrate is 20% or more in the wavelength range of 365 nm to 436 nm. Shift mask blank.
(Structure 8)
The reflectance reducing layer is composed of a material containing metal and silicon and at least one of nitrogen, oxygen and carbon, or a material containing metal and at least one of nitrogen, oxygen and carbon. The phase shift mask blank according to any one of the features 2 to 7.
(Structure 9)
The metal constituting the phase shift layer is any one of Zr, Mo, Ti, Ta, and W.
The metal constituting the metal layer is any one of Zr, Mo, Ti, Ta, and W.
The phase shift mask according to any one of configurations 2 to 8, wherein the metal constituting the reflectance reducing layer is any one of Zr, Mo, Cr, Ti, Ta, and W. blank.
(Structure 10)
The metal constituting each of the phase shift layer and the metal layer, or the metal constituting each layer of the phase shift layer, the metal layer, and the reflectance reducing layer is the same metal. The phase shift mask blank according to any one of 1 to 9.
(Structure 11)
The phase shift mask blank according to any one of configurations 1 to 10, further comprising a light-shielding film formed on the phase shift film.
(Structure 12)
The phase shift according to configuration 11, wherein the light-shielding film has a film surface reflectance of 15% or less in a wavelength range of 350 nm to 436 nm with respect to light incident from the surface side of the light-shielding film. Mask blank.

(Structure 13)
In the method of manufacturing a phase shift mask for manufacturing a display device,
A resist film is formed on the phase shift film of the phase shift mask blank according to any one of configurations 1 to 10, and a drawing process using a laser beam having any wavelength selected from the wavelength range of 350 nm to 436 nm is used. , And the process of forming a resist film pattern by development processing,
A method for manufacturing a phase shift mask, which comprises a step of etching the phase shift film using the resist film pattern as a mask to form a phase shift film pattern.
(Structure 14)
In the method of manufacturing a phase shift mask for manufacturing a display device,
A resist film is formed on the light-shielding film of the phase shift mask blank according to the configuration 11 or 12, and a drawing process and a developing process using a laser beam having any wavelength selected from the wavelength range of 350 nm to 436 nm are used. The process of forming a resist film pattern and
A step of forming the light-shielding film pattern by etching the light-shielding film using the resist film pattern as a mask.
A method for manufacturing a phase shift mask, which comprises a step of etching a phase shift film using the light shielding film pattern as a mask to form a phase shift film pattern.
(Structure 15)
In the manufacturing method of display devices
A phase shift mask in which a phase shift mask obtained by the method for manufacturing a phase shift mask according to the configuration 13 or 14 is arranged facing the resist film on a substrate with a resist film having a resist film formed on the substrate. Placement process and
A method for manufacturing a display device, which comprises a pattern transfer step of irradiating the phase shift mask with composite exposure light including i-line, h-line, and g-line to transfer the phase-shift film pattern.

According to the present invention, it is possible to provide a new phase shift film having excellent transmittance wavelength dependence.
According to the present invention, it is possible to provide a new phase shift film which is excellent in transmittance wavelength dependence and also excellent in other characteristics.
According to the present invention, it is possible to provide a new phase shift film having excellent transmittance wavelength dependence even with a high transmittance.
According to the present invention, it is possible to provide a new phase shift film having a significantly excellent transmittance wavelength dependence.
According to the present invention, it is possible to provide a new phase shift film having excellent transmittance wavelength dependence and excellent surface reflectance characteristics.
According to the present invention, it is possible to provide a new phase shift film which is excellent in transmittance wavelength dependence and also excellent backside reflectance characteristics.
According to the present invention, a phase shift mask blank for manufacturing a display device provided with the phase shift film according to the present invention, a method for manufacturing a phase shift mask using the phase shift mask blank, and the phase shift mask are used. It is possible to provide a method for manufacturing a display device that has been used.

It is a schematic diagram which shows the film structure of the phase shift mask blank which concerns on this invention. It is a schematic diagram which shows the other film composition of the phase shift mask blank which concerns on this invention. It is a schematic diagram which shows the other film composition of the phase shift mask blank which concerns on this invention. It is a transmittance spectrum of the phase shift film of the phase shift mask blank of Example 1 of this invention. It is a surface reflectance spectrum of the phase shift film of the phase shift mask blank of Example 1 of this invention. It is a back surface reflectance spectrum of the phase shift film of the phase shift mask blank of Example 1 of this invention. It is a transmittance spectrum of the phase shift film of the phase shift mask blank of Example 2 of this invention. It is a surface reflectance spectrum of the phase shift film of the phase shift mask blank of Example 2 of this invention. It is a back surface reflectance spectrum of the phase shift film of the phase shift mask blank of Example 2 of this invention. It is a transmittance spectrum of the phase shift film of the phase shift mask blank of the comparative example 1. FIG. It is the surface reflectance spectrum of the phase shift film of the phase shift mask blank of the comparative example 1. FIG. It is a back surface reflectance spectrum of the phase shift film of the phase shift mask blank of the comparative example 1. FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the following embodiments are one embodiment for embodying the present invention, and do not limit the present invention to the scope thereof. In the drawings, the same or equivalent parts may be designated by the same reference numerals to simplify or omit the description.

(Embodiment 1)
In the first embodiment, the phase shift mask blank will be described.

FIG. 1 is a schematic diagram showing the film configuration of the phase shift mask blank 10.
The phase shift mask blank 10 includes a transparent substrate 20 that is transparent (having translucency) with respect to exposure light, and a phase shift film 30 arranged on the transparent substrate 20. In FIG. 1, the phase shift film 30 has a laminated structure having a phase shift layer 31 and a metal layer 33 arranged in order from the transparent substrate 20 side, but the phase shift film 30 is sequentially arranged from the transparent substrate 20 side. It may be a laminated structure having an arranged phase shift layer 31 and a metal layer 33.

The phase shift layer 31 is arranged on the main surface of the transparent substrate 20. The phase shift layer 31 has a function of adjusting the transmittance and the phase difference with respect to the exposure light.
The phase shift layer 31 is formed of a material containing metal (M), silicon (Si), and at least one of nitrogen (N) and oxygen (O). Further, the phase shift layer 31 contains a metal (M), silicon (Si), at least one of nitrogen (N) and oxygen (O), and further of carbon (C) and fluorine (F). It may be formed of a material containing at least one of. For example, as a material for forming the phase shift layer 31, metal silicide oxide nitride (MSiON), metal silicide nitride (MSiN), metal silicide oxide (MSiO), metal silicide oxide carbide (MSiOCN), metal silicide carbonized. Nitride (MSICN), Metal silicide oxide carbide (MSiOC), Metal silicide oxide nitride fluoride (MSiONF), Metal silicide fluoride nitride (MSINF), Metal silicide oxide fluoride (MSiOF), Metal silicide oxide carbide fluoride (MSiOF) MSiOCNF), metal silicide carbide fluorinated fluoride (MSiCNF), metal silicide oxidized carbide fluoride (MSiOCF) and the like can be mentioned.
The metal (M) constituting the phase shift layer 31 is typically zirconium (Zr) and then molybdenum (Mo). Examples of the other metal (M) constituting the phase shift layer 31 include transition metals such as titanium (Ti), tantalum (Ta), and tungsten (W).
For example, examples of the material forming the phase shift layer 31 include ZrSiON, ZrSiN, ZrSiO, ZrSiOCN, ZrSiCN, ZrSiCO, ZrSiONF, ZrSiNF, ZrSiOF, ZrSiOCNF, ZrSiCNF, and ZrSiCOF.
For example, examples of the material forming the phase shift layer 31 include MoSiON, MoSiN, MoSiO, MoSiOCN, MoSiCN, MoSiCO, MoSiONF, MoSiNF, MoSiOF, MoSiOCNF, MoSiCNF, and MoSiCOF.
For example, examples of the material forming the phase shift layer 31 include TiSiON, TiSiN, TiSiO, TiSiOCN, TiSiCN, TiSiCO, TiSiONF, TiSiNF, TiSiOF, TiSiOCNF, TiSiCNF, and TiSiCOF.
The phase shift layer 31 may contain elements other than those listed above as long as the effects of the present invention are not deviated. Further, the ratio (atomic ratio) of the metal (M) and silicon (Si) of the metal silicide (MSi) of the phase shift layer 31 is M: Si = 1 in order to obtain the optical characteristics of the phase shift film 30 of the present invention. It is preferably 1 or more and 1: 9 or less. When the phase shift film 30 is patterned by wet etching, the ratio (atomic ratio) of the metal (M) and silicon (Si) of the phase shift layer 31 is M: Si = from the viewpoint of improving the pattern cross section. It is preferably 1: 1 or more and 1: 8 or less, more preferably M: Si = 1: 1 or more and 1: 4 or less.
Further, the metal (M) constituting the phase shift layer 31 may be an alloy containing one or more of the metals mentioned above.
The phase shift layer 31 can be formed by a sputtering method.

The reflectance reducing layer 32 is arranged above the phase shift layer 31. The reflectance reducing layer 32 has a function of reducing the reflectance for light incident from the surface side of the phase shift film 30 (that is, the side opposite to the transparent substrate 20 side with respect to the reflectance reducing layer 32).
The reflectance reducing layer 32 can be formed of a material containing metal (M), silicon (Si), and at least one of nitrogen (N) and oxygen (O). Further, the reflectance reducing layer 32 contains metal (M), silicon (Si), at least one of nitrogen (N) and oxygen (O), and further contains carbon (C) and fluorine (F). It may be formed of a material containing at least one of them. For example, as the material for forming the reflectance reducing layer 32, the same material as the material for forming the phase shift layer 31 described above can be used.
Further, the reflectance reducing layer 32 includes a metal (M), a material containing at least one of nitrogen (N), oxygen (O), carbon (C) and fluorine (F), or a metal (M). It can be formed of silicon (Si) and a material containing at least one of nitrogen (N), oxygen (O), carbon (C) and fluorine (F). For example, as a material for forming the reflectance reducing layer 32, a metal oxide (MO), a metal oxide nitride (MON), a metal oxide carbide (MOCN), a metal oxide carbide (MOC), and a metal oxide fluoride (MOF) are used. ), Metal Oxidized Hydroxide (MONF), Metal Oxidized Carbide Fluoride (MOCNF), Metal Oxidized Carbide (MOCF), Metal Nitride (MN), Metal Carbide (MCN), Metal Fluoride (MF) ), Metal nitride fluoride (MNF), metal carbide fluoride (MCNF), metal carbide fluoride (MCF) and the like.
The metal (M) constituting the reflectance reducing layer 32 is typically zirconium (Zr), molybdenum (Mo), and chromium (Cr). Examples of the other metal (M) constituting the reflectance reducing layer 32 include transition metals such as titanium (Ti), tantalum (Ta), and tungsten (W).
For example, examples of the material forming the reflectance reducing layer 32 include ZrSiON, ZrSiN, ZrSiO, ZrSiOCN, ZrSiCN, ZrSiCO, ZrSiONF, ZrSiNF, ZrSiOF, ZrSiOCNF, ZrSiCNF, and ZrSiCOF.
For example, examples of the material forming the reflectance reducing layer 32 include MoSiON, MoSiN, MoSiO, MoSiOCN, MoSiCN, MoSiCO, MoSiONF, MoSiNF, MoSiOF, MoSiOCNF, MoSiCNF, and MoSiCOF.
For example, examples of the material forming the reflectance reducing layer 32 include TiSiON, TiSiN, TiSiO, TiSiOCN, TiSiCN, TiSiCO, TiSiONF, TiSiNF, TiSiOF, TiSiOCNF, TiSiCNF, and TiSiCOF.
For example, the reflectance reducing layer 32 includes chromium oxide (CrO), chromium oxide nitride (CrON), chromium oxide nitride (CrOCN), chromium oxide carbide (CrCO), fluoride fluoride (CrOF), and chromium oxide. Fluoride Nitride (CrONF), Chromium Nitride Carbide Nitride (CrOCNF), Chromium Nitride Carbide (CrOCF), Chromium Nitride (CrN), Chromium Nitride (CrCN), Chromium Fluoride (CrF), Chromium Nitride Fluoride It can be formed of a chromium-based material such as a compound (CrNF), a chromium nitrided fluoride (CrCNF), or a chromium nitride fluoride (CrCF).
The reflectance reducing layer 32 may contain elements other than those listed above as long as the effects of the present invention are not deviated.
When the material of the reflectance reducing layer 32 is a metal silicide (MSi) -based material, the ratio (atomic ratio) of the metal (M) to silicon (Si) obtains the optical characteristics of the phase shift film 30 of the present invention. Therefore, M: Si = 1: 1 or more and 1: 9 or less is preferable. When the phase shift film 30 is patterned by wet etching, the ratio (atomic ratio) of the metal (M) and silicon (Si) of the reflectance reduction layer 32 is M: Si from the viewpoint of improving the pattern cross section. = 1: 2 or more and 1: 8 or less, more preferably M: Si = 1: 2 or more and 1: 4 or less.
Further, the metal (M) constituting the phase shift layer 31 may be an alloy containing one or more of the metals mentioned above.
The reflectance reducing layer 32 can be formed by a sputtering method.

The metal layer 33 is arranged between the phase shift layer 31 and the reflectance reducing layer 32. The metal layer 33 mainly has an action / function capable of adjusting the transmittance wavelength dependence of the phase shift layer 31 as a single layer. Specifically, the metal layer 33 has an action / function capable of reducing the transmittance wavelength dependence of the phase shift layer 31 as a single layer by a predetermined value (predetermined width) or more. The metal layer 33 has an action / function of controlling the transmittance wavelength dependence of the phase shift film 30 in the entire laminated body to be equal to or less than a predetermined value. In addition to these actions and functions, the metal layer 33 has a function of adjusting the transmittance with respect to the exposure light, and in combination with the reflectance reducing layer 32, the surface side of the phase shift film 30 (with respect to the transparent substrate 20 side). It has a function of reducing the reflectance for light incident from the opposite side). The metal layer 33, in combination with the phase shift layer 31, has a function of increasing the back surface reflectance with respect to the light incident on the phase shift film 30 from the back surface side of the transparent substrate 20. The back surface of the transparent substrate 20 means the main surface of the two main surfaces of the transparent substrate 20 opposite to the phase shift film 30.
The metal layer 33 is a material composed of metal (M) and silicon (Si), or metal (M) and silicon (Si), carbon (C), fluorine (F), nitrogen (N), and oxygen. It is composed of at least one of (O). Further, the content of the metal contained in the metal layer 33 is higher than the content of the metal contained in the phase shift layer 31, or the total content of the metal and silicon contained in the metal layer 33 is the phase shift layer 31. It consists of materials that are higher than the total content of metal and silicon contained in.
For example, examples of the material forming the metal layer 33 include metal silicide (MSi), metal silicide carbide (MSIC), and metal silicide carbide fluoride (MSiCF).
The metal (M) constituting the metal layer 33 is typically zirconium (Zr). Examples of the other metal (M) constituting the metal layer 33 include transition metals such as molybdenum (Mo), titanium (Ti), tantalum (Ta), and tungsten (W).
For example, examples of the material forming the metal layer 33 include ZrSi, ZrSiC, ZrSiCF, ZrSiN, and ZrSiCN.
For example, examples of the material forming the metal layer 33 include MoSi, MoSiC, MoSiCF, MoSiN, and MoSiCN.
For example, examples of the material forming the metal layer 33 include TiSi, TiSiC, TiSiCF, TiSiN, and TiSiCN.
When the metal layer 33 is a metal silicide (MSi), the ratio (atomic ratio) of the metal (M) and silicon (Si) of the metal layer 33 is set in order to obtain the optical characteristics of the phase shift film 30 of the present invention. M: Si = 1: 1 or more and 1: 9 or less is preferable. When the phase shift film 30 is patterned by wet etching, the ratio (atomic ratio) of the metal (M) and silicon (Si) of the metal layer 33 is M: Si = 1 from the viewpoint of improving the pattern cross section. : 2 or more and 1: 8 or less, more preferably M: Si = 1: 2 or more and 1: 4 or less.
Further, the metal (M) constituting the metal layer 33 may be an alloy containing one or more of the above-mentioned metals.
Further, by providing the metal layer 33, the sheet resistance of the phase shift film is lowered, so that it is possible to prevent the phase shift mask blank and the phase shift mask from being charged up. When the metal layer 33 is not provided, foreign matter adheres and electrostatic breakdown is likely to occur due to charge-up.
The metal layer 33 may contain elements other than those listed above as long as the effects of the present invention are not deviated.
The metal layer 33 can be formed by a sputtering method.

The metal layer 33 has a metal element (M) content (atomic%) higher than the metal element (M) content (atomic%) of the reflectance reduction layer 32, or the metal layer 33 has a reflectance reduction layer 32. The total content of the metal element (M) and silicon (Si) is higher than the total content of the metal element (M) and silicon (Si) (atomic%).
The difference between the metal element (M) content of the metal layer 33 and the metal element (M) content of the reflectance reduction layer 32, or the total content of the metal element (M) and silicon (Si) of the metal layer 33. The difference in the total content of the metal element (M) and silicon (Si) in the reflectance reducing layer 32 is preferably 30 to 90 atomic%, more preferably 50 to 80 atomic%. When the difference between the metal element (M) content or the total content of the metal element (M) and silicon (Si) is 60 to 80 atomic%, the metal layer 33 and the reflectance reducing layer 32 are used. Since the reflectance in the above wavelength range of the interface (wavelength of 365 nm or wavelength range of 365 nm to 436 nm) can be increased, the effect of reducing the reflectance is further exhibited, which is preferable.
The etching rate of the metal layer 33 is determined by including carbon (C), fluorine (F), nitrogen (N), and oxygen (O) in the metal silicide-based material of metal (M) and silicon (Si). Can be adjusted. For example, the wet etching rate can be slowed down by containing carbon (C), fluorine (F), or nitrogen (N) in the metal silicide-based material of metal (M) and silicon (Si). Further, the etching rates of the phase shift layer 31 and the reflectance reducing layer 32 formed above and below the metal layer 33 are as follows: carbon (C) and fluorine (C) and fluorine (C) and fluorine (C) and fluorine ( The wet etching rate can be slowed down by containing F) and nitrogen (N), and by containing oxygen (O) in the metal silicide-based material of metal (M) and silicon (Si), wet. The etching speed can be increased. As a result, the etching rate of each layer constituting the phase shift film 30 can be controlled to improve the cross-sectional shape of the phase shift film 30 after etching.
The metal layer 33 has a metal element (M) content (atomic%) higher than the metal element (M) content (atomic%) of the phase shift layer 31.
The difference between the metal element (M) content of the metal layer 33 and the metal element (M) content of the phase shift layer 31 is preferably 30 to 90 atomic%, more preferably 50 to 80 atomic%. be. When the difference in the metal element (M) content between the metal layer 33 and the phase shift layer 31 is 60 to 80 atomic%, the above wavelength range (wavelength of 365 nm, or a wavelength of 365 nm) at the interface between the metal layer 33 and the phase shift layer 31 is used. Since the back surface reflectance in the wavelength range of 365 nm to 436 nm can be increased, the back surface reflectance can be further increased, which is preferable.
The metal element (M) content can be measured using an X-ray photoelectron spectrometer (XPS, ESCA).

The thickness of the phase shift layer 31 in the phase shift film 3 is preferably, but is not limited to, in the range of, for example, 50 nm or more and 140 nm or less, and further 60 nm or more and 120 nm or less. From the viewpoint of increasing the back surface reflectance, the thickness of the phase shift layer 31 is preferably 70 nm or more and 95 nm or less, more preferably 70 nm or more and 85 nm or less.
The thickness of the metal layer 33 in the phase shift film 3 is preferably thinner than the thickness of the phase shift layer. The thickness of the metal layer 33 in the phase shift film 3 is preferably thinner than the thickness of the reflectance reducing layer. The thickness of the metal layer 33 in the phase shift film 3 varies depending on the type of metal (M) and cannot be unequivocally determined, but is, for example, in the range of 2.5 nm or more and 50 nm or less, and further 2.5 nm or more and 40 nm or less. Is preferable, but the present invention is not limited to this. It is substantially difficult to form a metal layer uniformly over the substrate surface with a thickness of less than 2.5 nm. Further, if the metal layer is formed with a thickness of more than 50 nm, the transmittance may decrease, and for example, the transmittance of the phase shift film 3 at a wavelength of 365 nm may be less than 1%. From the viewpoint of increasing the surface reflectance, the thickness of the metal layer 33 should be thick. From the viewpoint of increasing the back surface reflectance, the thickness of the metal layer 33 is 25 nm or more. From the above viewpoint, the film thickness of the metal layer 33 is preferably 25 nm or more and 50 nm or less, and more preferably 25 nm or more and 40 nm or less.
The thickness of the reflectance reducing layer 32 in the phase shift film 3 is preferably, but is not limited to, in the range of, for example, 15 nm or more and 40 nm or less, and further 20 nm or more and 35 nm or less.

Each of the phase shift layer 31, the metal layer 33 and the reflectance reducing layer 32 preferably has a refractive index of 2.0 or more in the wavelength range of 365 nm to 436 nm. Having a refractive index of 2.0 or more makes it possible to reduce the film thickness of the phase shift film 30 required to obtain desired optical characteristics (transmittance and phase difference). Therefore, the phase shift mask produced by using the phase shift mask blank 10 provided with the phase shift film 30 can be provided with a phase shift film pattern having an excellent pattern cross-sectional shape and excellent CD uniformity.
The refractive index can be measured using an n & k analyzer, an ellipsometer, or the like.

Due to the laminated structure of the phase shift layer 31 and the metal layer 33, or the laminated structure of the phase shift layer 31, the metal layer 33 and the reflectance reduction layer 32, the transmittance and the phase difference of the phase shift film 30 with respect to the exposure light are predetermined optics. In addition to having characteristics, the transmittance wavelength dependence (fluctuation range of transmittance) has a predetermined value.
The transmittance of the phase shift film 30 with respect to the exposure light satisfies the value required for the phase shift film 30. The transmittance of the phase shift film 30 is preferably 1% or more and 50% or less with respect to the light having a predetermined wavelength (hereinafter referred to as a representative wavelength) contained in the exposure light. In the case of the high transmittance type, the transmittance of the phase shift film 30 is 15% or more and 50% or less. That is, when the exposure light is composite light including j-line (wavelength: 313 nm), i-line (wavelength: 365 nm), h-line (wavelength: 405 nm), and g-line (wavelength: 436 nm), the phase shift film 30 is the composite light. It has the above-mentioned transmittance for light of a representative wavelength included in the wavelength range. Further, for example, when the exposure light is a composite light including i-line, h-line and g-line, the phase shift film 30 has the above-mentioned transmittance for any of i-line, h-line and g-line. ..
The phase difference of the phase shift film 30 with respect to the exposure light satisfies the value required for 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 contained in the exposure light. This makes it possible to change the phase of the light of the representative wavelength included in the exposure light from 160 ° to 200 °. Therefore, a phase difference of 160 to 200 ° occurs between the light having the representative wavelength transmitted through the phase shift film 30 and the light having the representative wavelength transmitted only through the transparent substrate 20. That is, when the exposure light is a composite light containing light in a 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 exposure light is a composite light including i-line, h-line, and g-line, the phase shift film 30 has the above-mentioned phase difference with respect to any of i-line, h-line, and g-line.
The phase shift film 30 has a transmittance wavelength dependence of 5.5% or less in the wavelength range of 365 nm or more and 436 nm or less.
The transmittance, transmittance wavelength dependence and phase difference of the phase shift film 30 are determined by the phase shift layer 31 and the metal layer 33 constituting the phase shift film 30, or the phase shift layer 31, the metal layer 33 and the reflectance reducing layer 32. It can be controlled by adjusting the material, composition and thickness of each of the above. Therefore, in this embodiment, the phase shift layer 31 and the metal layer 33, or the phase shift, so that the transmittance, the transmittance wavelength dependence, and the phase difference of the phase shift film 30 have the above-mentioned predetermined optical characteristics. The materials, compositions, and thicknesses of the layer 31, the metal layer 33, and the reflectance reducing layer 32 are adjusted. The transmittance and transmittance wavelength dependence of the phase shift film 30 are mainly affected by the material, composition and thickness of the phase shift layer 31 and the metal layer 33. The refractive index and phase difference (phase shift amount) of the phase shift film 30 are mainly affected by the material, composition and thickness of the phase shift layer 31.
The transmittance and the phase difference can be measured by using a phase shift amount measuring device or the like.

The surface reflectance of the phase shift film 30 with respect to the light incident from the surface side of the phase shift film 30 is 10% or less in the wavelength range of 365 nm to 436 nm, and / or the light incident from the surface side of the phase shift film 30. The surface reflectivity of the phase shift film 30 is 15% or less in the wavelength range of 350 nm to 436 nm. When the surface reflectance of the phase shift film 30 is 10% or less in the wavelength range of 365 nm to 436 nm and / or the surface reflectance of the phase shift film 30 is 15% or less in the wavelength range of 350 nm to 436 nm, the phase shift film When a resist film is formed on the surface and a pattern is drawn by a laser drawing machine or the like, it is less affected by the standing wave generated by the overlapping of the light used for drawing and the reflected light. Therefore, at the time of pattern drawing, the roughness of the edge portion of the resist film pattern cross section on the phase shift film 30 can be suppressed, and the pattern accuracy can be improved. Therefore, it is possible to form a phase shift mask having excellent pattern accuracy. Further, since the surface reflectance with respect to the exposure light is reduced, when a display device is manufactured by performing pattern transfer using a phase shift mask, the transfer pattern is blurred (flare) due to the reflected light from the display device substrate. And CD error can be prevented.
The fluctuation range of the surface reflectance of the phase shift film 30 is preferably 10% or less, more preferably 8% or less, still more preferably 5% or less, still more preferably 3% or less in the wavelength range of 365 nm to 436 nm. be. The fluctuation range of the surface reflectance of the phase shift film 30 is preferably 12% or less, more preferably 10% or less, still more preferably 8% or less, still more preferably 5 in the wavelength range of 350 nm to 436 nm. % Or less.
The back surface reflectance of the phase shift film 30 with respect to the light incident from the back surface side of the transparent substrate 20 is one, preferably two, of i-line (365 nm), h-line (405 nm), and g-line (436 nm). At the above wavelengths, it is more preferably 15% or more, more preferably 18% or more, still more preferably 20% or more, still more preferably 30% or more in the wavelength range of 365 nm to 436 nm. As a result, the phase shift film 30 can absorb the exposure light and reduce the pattern position shift caused by thermal expansion. The fluctuation range of the back surface reflectance of the phase shift film 30 is 20% or less, more preferably 15% or less, still more preferably 10% or less, still more preferably 5% or less in the wavelength range of 365 nm to 436 nm. Is preferable.
The surface reflectance of the phase shift film 30 and its fluctuation width adjust 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. It can be controlled by this. Since the extinction coefficient and the refractive index can be controlled by adjusting the composition, in this embodiment, the surface reflectance of the phase shift film 30 and the fluctuation range thereof have the above-mentioned predetermined physical properties. The materials, compositions, and thicknesses of the phase shift layer 31, the metal layer 33, and the reflectance reducing layer 32 are adjusted. The same applies to the back surface reflectance of the phase shift film 30. The surface reflectance of the phase shift film 30 and its fluctuation range are mainly affected by the materials, compositions, and thicknesses of the metal layer 33 and the reflectance reducing layer 32, respectively. Further, the back surface reflectance of the phase shift film 30 and its fluctuation range are mainly affected by the materials, compositions and thicknesses of the metal layer 33 and the phase shift layer 31, respectively.
The front surface reflectance and the back surface reflectance can be measured using a spectrophotometer or the like. The fluctuation range of the surface reflectance is obtained from the difference between the maximum reflectance and the minimum reflectance in the wavelength range of 350 nm to 436 nm or the wavelength range of 365 nm to 436 nm. Further, the fluctuation range of the back surface reflectance is obtained from the difference between the maximum reflectance and the minimum reflectance in the wavelength range of 365 nm to 436 nm.

The phase shift layer 31 may be composed of a single film having a uniform composition, may be composed of a plurality of films having different compositions, or the composition may be continuously changed in the thickness direction. It may be composed of a single film, or it may be composed of a plurality of films having different compositions and the plurality of films may be composed of a film whose composition continuously changes in the thickness direction. .. The same applies to the metal layer 33 and the reflectance reducing layer 32.

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

When the phase shift mask blank 10 includes 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 forming the light-shielding film pattern 40 is not particularly limited as long as it is a material having a function of blocking the transmission of exposure light. For example, it contains a chromium-based material, a material containing the above-mentioned metal (M) (one of M: Zr, Mo, Ti, Ta, and W), and the above-mentioned metal (M) and silicon (Si). Materials and the like can be mentioned. Examples of the chromium-based material include chromium (Cr) or a chromium compound containing chromium (Cr) and at least one of carbon (C) and nitrogen (N). In addition, a chromium compound containing chromium (Cr) and at least one of oxygen (O) and fluorine (F), or at least one of chromium (Cr), carbon (C) and nitrogen (N). And further include chromium compounds containing at least one of oxygen (O) and fluorine (F). For example, examples of the material forming the light-shielding film pattern 40 include Cr, CrC, CrN, CrO, CrCN, CrON, CrCO, and CrCON.
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 laminated, the optical density with respect to the exposure light is preferably 3 or more, more preferably 4 or more, still more preferably 5 or more.
The optical density can be measured using a spectrophotometer, an OD meter, or the like.

The light-shielding film pattern 40 may be composed of a single film having a uniform composition, may be composed of a plurality of films having different compositions, or may have a continuous composition in the thickness direction. It may consist of a single changing film, or it may consist of a plurality of films having different compositions, and the plurality of films may each consist of a film whose composition continuously changes in the thickness direction. good.

In FIGS. 1 and 2, the phase shift mask blank 10 may include a resist film on the phase shift film 30.

FIG. 3 is a schematic diagram showing another film configuration of the phase shift mask blank 10.
Even if the phase shift mask blank 10 of the present invention includes a transparent substrate 20 and a phase shift film 30 formed on the transparent substrate 20, a light shielding film 45 is further formed on the phase shift 30 film. good. Further, a resist film (not shown) may be formed on the light-shielding film 45.
In this case, as the light-shielding film 45, the same contents as those described in the light-shielding film pattern 40 can be applied. For example, as the material of the light-shielding film 45, the same material as the material forming the light-shielding film pattern 40 can be used. If necessary, the light-shielding film 45 may have an antireflection function in which a surface reflectance reducing layer 47 for reducing the film surface reflectance of the light-shielding film 45 with respect to light incident on the surface side of the light-shielding film 45 is formed. No. In this case, the light-shielding film 45 is configured to include a light-shielding layer 46 having a function of blocking the transmission of exposure light from the phase shift film 30 side, and a surface reflectance reducing layer 47. When the light-shielding film 45 includes the surface reflectance reducing layer 47, the surface reflectance reducing layer is 10% or less in the wavelength range of 365 nm to 436 nm, and / or the film surface reflectance of the surface reflectance reducing layer 47. Is preferably 15% or less in the wavelength range of 350 nm to 436 nm. Further, if necessary, another functional film is formed between the phase shift film 30 and the light-shielding film pattern 40 (see FIG. 2), between the phase shift film 30 and the light-shielding film 45, and on the light-shielding film 45. You can also do it. Examples of the functional film include an etching blocking film and an etching mask film.

Next, a method of manufacturing the phase shift mask blank 10 of this embodiment will be described.
The phase shift mask blank 10 is manufactured by performing the following preparation steps and a phase shift film forming step.
Hereinafter, each step will be described in detail.

(Preparation process)
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 a material having translucency with respect to the exposure light used. For example, synthetic quartz glass, soda lime glass, and non-alkali glass can be mentioned. The transparent substrate 20 has a transmittance of 85% or more, preferably 90% or more, with respect to the exposure light, for example, assuming that there is no surface reflection loss.
In the case of manufacturing the phase shift mask blank 10 provided with the light-shielding film pattern 40, a light-shielding film made of, for example, a chromium-based material is formed on the transparent substrate 20 by sputtering. After that, a resist film pattern is formed on the light-shielding film, and the light-shielding film is etched by using the resist film pattern as a mask to form the light-shielding film pattern 40. Then, the resist film pattern is peeled off. These steps are omitted in the case of manufacturing the phase shift mask blank 10 without the light-shielding film pattern 40.

(Phase shift film forming process)
In the phase shift film forming step, the phase shift film 30 is formed on the transparent substrate 20 by sputtering. 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 and forming a metal layer 33 on the phase shift layer 31. Alternatively, the phase shift film 30 has a phase shift layer 31 formed on the main surface of the transparent substrate 20, a metal layer 33 formed on the phase shift layer 31, and a reflectance reducing layer 32 formed on the metal layer 33. It is formed by forming a film.

The film formation of the phase shift layer 31 and the reflectance reducing layer 32 involves one or more sputter targets containing a metal (M), a metal (M) compound, a metal silicide (MSi) or a metal silicide (MSi) compound. Inert gas, including at least one selected from the group consisting of, for example, helium gas, neon gas, argon gas, krypton gas and xenone gas, and oxygen gas, nitrogen gas, nitrogen monoxide gas, nitrogen dioxide gas, dioxide gas. It is carried out in a sputter gas atmosphere consisting of a mixed gas with an active gas containing at least one selected from the group consisting of carbon gas, hydrocarbon gas and fluorine gas. Examples of the hydrocarbon gas include methane gas, butane gas, propane gas, styrene gas and the like.
The film formation of the metal layer 33 is performed using, for example, helium using one or more sputter targets containing a metal (M), a metal (M) compound, a metal silicide (MSi) or a metal silicide (MSi) compound. It is carried out in an inert gas atmosphere containing at least one selected from the group consisting of gas, neon gas, argon gas, krypton gas and xenon gas. When the metal layer 33 contains carbon, the film formation of the metal layer 33 is performed in a sputter gas atmosphere composed of a mixed gas of the inert gas and the hydrocarbon gas. When the metal layer 33 contains nitrogen, oxygen, and fluorine, the film formation of the metal layer 33 is performed in the same manner as the film formation of the phase shift layer 31 and the reflectance reduction layer 32.

When the phase shift layer 31 and the metal layer 33 are formed, or when the phase shift layer 31, the metal layer 33 and the transmittance reduction layer 32 are formed, the phase shift layer 31, the metal layer 33 and the transmittance reduction layer 32 are formed. Each material, composition and thickness of the phase shift film 30 has the predetermined optical characteristics described above for the transmittance and the phase difference of the phase shift film 30, and the transmittance wavelength dependence of the phase shift film 30 (the fluctuation range of the transmittance). ) Has the above-mentioned predetermined characteristics, and further, the front surface transmittance and its fluctuation width, the back surface reflectance and its fluctuation width of the phase shift film 30 are adjusted to have the above-mentioned predetermined characteristics. The composition of each of the phase shift layer 31, the metal layer 33, and the reflectance reducing layer 32 can be controlled by the composition of the sputtering gas, the flow rate, and the like. The thickness of each of the phase shift layer 31, the metal layer 33, and the reflectance reduction layer 32 can be controlled by the sputtering power, the sputtering time, and the like. When the sputtering apparatus is an in-line sputtering apparatus, the thicknesses of the phase shift layer 31, the metal layer 33, and the reflectance reducing layer 32 can be controlled by the transfer speed of the substrate.

When the phase shift layer 31 is composed of a single film having a uniform composition, the above-mentioned film forming process is performed only once without changing the composition and flow rate of the sputtering gas. When the phase shift layer 31 is composed of a plurality of films having different compositions, the above-mentioned film forming process is performed a plurality of times by changing the composition and flow rate of the sputtering gas for each film forming process. When the phase shift layer 31 is composed 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. When the phase shift layer 31 is composed of a plurality of films having different compositions and each of the plurality of films is composed of a film whose composition continuously changes in the thickness direction, the above-mentioned film forming process is carried out with the composition and flow rate of the spatter gas. Do it multiple times while changing.
The same applies to the film formation of the metal layer 33 and the film formation of the reflectance reduction layer 32. When the film forming process is performed a plurality of times, the sputtering power applied to the sputtering target can be reduced.

It is preferable that the phase shift layer 31, the metal layer 33, and the reflectance reducing layer 32 are continuously formed by using a sputtering device and taking the transparent substrate 20 out of the device without exposing it to the atmosphere. By continuously forming a film without taking it out of the apparatus, it is possible to prevent unintended surface oxidation and surface carbonization of each layer. Unintended surface oxidation or surface carbonization of each layer transfers the phase shift film pattern to the laser beam used when drawing the resist film formed on the phase shift film 30 or the resist film formed on the display device substrate. There is a possibility that the reflectance with respect to the exposure light used may be changed, or the etching rate of the oxidized portion or the carbonized portion may be changed.
The phase shift layer 31, the metal layer 33, and the reflectance reducing layer 32 can be continuously formed by using an in-line sputtering apparatus or a cluster type sputtering apparatus without being exposed to the atmosphere.

As shown in FIG. 3, when the phase shift mask blank 10 manufactures the phase shift mask blank 10 having the phase shift film 30 and the light shielding film 45 on the transparent substrate 20, the phase is formed by the phase shift film forming step described above. After forming the shift film 30, the light-shielding film 45 is formed on the phase shift film 30.
(Light-shielding film forming process)
In the light-shielding film forming step, the light-shielding film 45 is formed on the phase shift film 30 by sputtering.
The light-shielding film 45 is formed by forming a light-shielding layer 46 on the phase shift film 30 and, if necessary, a surface reflectance reducing layer 47 on the light-shielding layer 46. The film formation of the light-shielding layer 46 and the surface reflectance reducing layer 47 involves one or more sputter targets containing a metal (M), a metal (M) compound, a metal silicide (MSi) or a metal silicide (MSi) compound. Inert gases, including, for example, an inert gas comprising at least one selected from the group consisting of helium gas, neon gas, argon gas, krypton gas and xenone gas, and oxygen gas, nitrogen gas, nitrogen monoxide gas, nitrogen dioxide gas, dioxide gas. It is carried out in a sputter gas atmosphere composed of a mixed gas with an active gas containing at least one selected from the group consisting of a carbon gas, a hydrocarbon gas and a fluorine gas, or a sputter gas atmosphere containing at least one of the inert gases. Examples of the hydrocarbon gas include methane gas, butane gas, propane gas, styrene gas and the like.
When forming the light-shielding layer 46 and the surface reflectance-reducing layer 47, the materials, compositions, and thicknesses of the light-shielding layer 46 and the surface reflectance-reducing layer 47 are the portions where the phase shift film 30 and the light-shielding film 45 are laminated. In, the optical density with respect to the exposure light and the film surface reflectance are adjusted so as to have the above-mentioned predetermined optical characteristics. The composition of each of the light-shielding layer 46 and the surface reflectance reducing layer 47 can be controlled by the composition of the sputtering gas, the flow rate, and the like. The thickness of each of the light-shielding layer 46 and the surface reflectance reducing layer 47 can be defined by the sputtering power, the sputtering time, and the like. Further, when the sputtering apparatus is an in-line type sputtering apparatus, the thickness of each of the light-shielding layer 46 and the surface reflectance reducing layer 47 can be controlled by the transfer speed of the substrate.
When each of the light-shielding layer 46 and the surface reflectance reducing layer 47 is composed of a single film having a uniform composition, the above-mentioned film forming process is performed only once without changing the composition and flow rate of the sputtering gas. When each of the light-shielding layer 46 and the surface reflectance reducing layer 47 is made of Fukusu films having different compositions, the above-mentioned film forming process is performed a plurality of times by changing the composition and flow rate of the spatter gas for each film forming process. When each of the light-shielding layer 46 and the surface reflectance reducing layer 47 is composed of a single film whose composition changes continuously in the thickness direction, the above-mentioned film forming process is performed while changing the composition and flow rate of the spatter gas. Do it only once. When each of the light-shielding layer 46 and the surface reflectance reducing layer 47 is composed of a plurality of films having different compositions and the plurality of films are composed of films whose compositions continuously change in the thickness direction, the above-mentioned film forming process is performed. Is performed a plurality of times while changing the composition and flow rate of the spatter gas.
The light-shielding layer 46 and the surface reflectance reducing layer 47 can be continuously formed by using an in-line sputtering device or a cluster-type sputtering device without being exposed to the atmosphere.
When manufacturing the phase shift mask blank 10 including the resist film, next, a resist film is formed on the light-shielding film.

Since the phase shift mask blank 10 of the first embodiment has the phase shift layer 31 and the metal layer 33 as the phase shift film 30, the phase shift mask blank 10 satisfies predetermined optical characteristics of phase difference and transmittance. Excellent transmittance wavelength dependence (within 5.5%) in the wavelength range of 365 nm or more and 436 nm or less. Further, the phase shift mask blank 10 having the phase shift film 30 provided with the phase shift layer 31, the metal layer 33, and the reflectance reducing layer 32 satisfies predetermined optical characteristics of phase difference and transmittance, and has a wavelength of 365 nm or more. In the wavelength range of 436 nm or less, the transmittance wavelength dependence is excellent (within 5.5%), the front surface reflectance characteristic is also excellent (10% or less), and the back surface reflectance characteristic is also excellent.

(Embodiment 2)
In the second embodiment, a method of manufacturing a phase shift mask using the phase shift mask blank 10 of the first embodiment will be described. Embodiment 2 includes embodiment 2-1 and embodiment 2-2. Of the second embodiments, the second embodiment is a method for manufacturing a phase shift mask using the phase shift mask blank 10 in which the phase shift film 30 and the resist film are formed on the transparent substrate 20. Further, in the second embodiment of the second embodiment, the second embodiment is a method for manufacturing a phase shift mask using a phase shift mask blank 10 in which a phase shift film 30, a light shielding film 45, and a resist film are formed on a transparent substrate 20. Is. In the method for manufacturing a phase shift mask according to the 2-1 embodiment, the phase shift mask is manufactured by performing the following resist film pattern forming step and phase shift film pattern forming step. Further, in the method for manufacturing the phase shift mask according to the second embodiment, the phase shift mask is manufactured by performing the following resist film pattern forming step, light shielding film pattern forming step, and phase shift film pattern forming step.
Hereinafter, each step will be described in detail.

(Resist film pattern forming 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 blank 10 of the first embodiment described with reference to FIG. 1 or FIG. The resist film material used is not particularly limited. For example, the resist film used is one that is sensitive to laser light having any wavelength selected from the wavelength range of 350 nm to 436 nm described later, or is selected from the wavelength range of 365 nm to 436 nm. Those that are sensitive to laser light having that wavelength are used. Further, the resist film may be either a positive type or a negative type.
Then, a laser beam having any wavelength selected from the wavelength range of 350 nm to 436 nm or a laser beam having any wavelength selected from the wavelength range of 365 nm to 436 nm is used to apply a predetermined value to the resist film. Draw a pattern. Examples of the pattern drawn on the resist film include a line-and-space pattern and a hole pattern.
Then, the resist film is developed with a predetermined developer to form a resist film pattern on the phase shift film 30.
If the phase shift mask blank 10 already has a resist film on the phase shift film 30, the step of forming the resist film on the phase shift film 30 is omitted.

(Light-shielding film pattern forming process)
In the light-shielding film pattern forming step in the method for manufacturing a phase shift mask according to the second embodiment, the light-shielding film 45 (FIG. 3) is etched with the resist film pattern as a mask to form the light-shielding film pattern.
The etching medium (etching solution, etching gas) for etching the light-shielding film 45 is not particularly limited as long as it can selectively etch each of the light-shielding layer 46 and the surface reflectance reducing layer 47 constituting the light-shielding film 45.
Specifically, for example, as an etching solution for wet etching a metal silicide-based material, at least one fluorine compound selected from hydrofluoric acid, hydrofluoric acid, and ammonium hydrogenfluoride, and hydrogen peroxide. An etching solution containing at least one oxidizing agent selected from nitric acid and sulfuric acid, and an etching solution containing hydrogen peroxide, ammonium fluoride, and at least one oxidizing agent selected from phosphoric acid, sulfuric acid, and nitric acid. Can be mentioned. Examples of the etching gas for dry etching the metal silicide-based material layer include fluorine-based gas and chlorine-based gas. Examples of the fluorine-based gas include CF4 gas, CHF3 gas, SF6 gas, and a mixture of these gases and O2 gas.
Further, for example, examples of the etching solution for wet etching a chromium-based material include an etching solution containing dicerium nitric acid ammonium nitrate and perchloric acid, and an etching gas composed of a mixed gas of chlorine gas and oxygen gas.
(Phase shift film pattern forming process)
In the phase shift film pattern forming step, in the method of manufacturing the phase shift mask according to the 2-1 embodiment, first, the phase shift film 30 is etched by using the resist film pattern as a mask to form the phase shift film pattern. On the other hand, in the method for manufacturing a phase shift mask according to the second embodiment, the light-shielding film 45 is etched using the resist film pattern as a mask to form a light-shielding film pattern, and then the light-shielding film pattern is used as a mask for phase shift. The film 30 is etched to form a phase shift film pattern.
The etching medium (etching solution, etching gas) for etching the phase shift film 30 may be one capable of selectively etching each of the phase shift layer 31, the metal layer 33, and the reflectance reduction layer 32 constituting the phase shift film 30. However, there are no particular restrictions.
Specifically, for example, as an etching solution for wet etching a metal silicide-based material, at least one fluorine compound selected from hydrofluoric acid, hydrofluoric acid, and ammonium hydrogenfluoride, and hydrogen peroxide. An etching solution containing at least one oxidizing agent selected from nitric acid and sulfuric acid, and an etching solution containing hydrogen peroxide, ammonium fluoride, and at least one oxidizing agent selected from phosphoric acid, sulfuric acid, and nitric acid. Can be mentioned. Examples of the etching gas for dry etching the metal silicide-based material layer include fluorine-based gas and chlorine-based gas. Examples of the fluorine-based gas include CF4 gas, CHF3 gas, SF6 gas, and a mixture of these gases and O2 gas.
Further, for example, examples of the etching solution for wet etching a chromium-based material include an etching solution containing dicerium nitric acid ammonium nitrate and perchloric acid, and an etching gas composed of a mixed gas of chlorine gas and oxygen gas.
Then, the resist film pattern is peeled off using a resist stripping solution or by ashing.
In the method for manufacturing a phase shift mask according to the second embodiment, the light-shielding film pattern may be removed by an etching medium for etching the light-shielding film 45, or the phase-shift film pattern size may be displayed on the phase-shift film pattern. When forming a light-shielding film pattern having a different pattern size, the resist film pattern is formed on the light-shielding film pattern again, and then the light-shielding film pattern forming step is performed using the resist film pattern as a mask.

Since the phase shift mask of the second embodiment has the phase shift layer 31 and the metal layer 33 as the phase shift film 30, the phase shift mask has a phase difference and a transmittance of 365 nm or more after satisfying predetermined optical characteristics. Excellent transmittance wavelength dependence (within 5.5%) in the wavelength range of 436 nm or less. Further, the phase shift mask blank 10 having the phase shift film 30 provided with the phase shift layer 31, the metal layer 33, and the reflectance reducing layer 32 satisfies predetermined optical characteristics of phase difference and transmittance, and has a wavelength of 365 nm or more. In the wavelength range of 436 nm or less, the transmittance wavelength dependence is excellent (within 5.5%), the front surface reflectance characteristic is also excellent (10% or less), and the back surface reflectance characteristic is also excellent. Further, it has a characteristic that the resolution of the transfer pattern transferred on the display device substrate can be improved corresponding to the excellent characteristic of the phase shift mask.

(Embodiment 3)
In the third embodiment, a method of manufacturing the display device will be described. The display device is manufactured by performing the following mask mounting step and pattern transfer step.
Hereinafter, each step will be described in detail.

(Placement process)
In the mounting step (placement step), the phase shift mask manufactured in the second embodiment is placed (placed) on the mask stage of the exposure apparatus. Here, the phase shift mask is arranged so that its pattern forming surface side faces the resist film formed on the display device substrate via the projection optical system of the exposure device.

(Pattern transfer process)
In the pattern transfer step, the phase shift mask is irradiated with exposure light to transfer the phase shift film pattern to the resist film formed on the display device substrate. The exposure light is a composite light containing multiple wavelengths selected from the wavelength range of 365 nm to 436 nm, a composite light containing multiple wavelengths selected from the wavelength range of 313 nm to 436 nm, and a composite light containing light of multiple wavelengths selected from the wavelength range of 313 nm to 436 nm. It is monochromatic light selected by cutting a certain wavelength range from the range with a filter or the like. For example, the exposure light is a composite light including i-line, h-line and g-line, a mixed light including j-line, i-line, h-line and g-line, and i-line monochromatic light. When composite light is used as the exposure light, the exposure light intensity can be increased and the throughput can be increased, so that the manufacturing cost of the display device can be reduced.

According to the method for manufacturing a display device according to the third embodiment, a high-resolution, high-definition display device can be manufactured. For example, a fine pattern (eg, a contact hole of 1.8 μm) can be formed.

(Embodiment 4)
In the fourth embodiment, a specific example of the phase shift mask blank will be described.

As described above, in the phase shift film composed of three laminated films, the present inventor sequentially has a predetermined phase shift layer (for example, ZrSiON, MoSiON, TiSiON, etc.) and a predetermined metal layer (intermediate) from the substrate side. By combining a layer) (for example, ZrSi, MoSi, TiSi, etc.) and a predetermined reflectance reducing layer (for example, ZrSiON, MoSiON, TiSiON, CrO, CrOCN, CrON, etc.), the predetermined transmittance wavelength dependence is reduced. Can be done (function 1) (for example, within 5.5%), surface reflectance can be reduced (function 2), and surface reflectance can be reduced (for example, 10% or less) (function 3), backside reflection. It was found that the rate can be controlled (function 4), and all of them can be combined. In addition to this, it was found that it can have the characteristic of high transmittance (function 5).

As a typical example of the above, there is a three-layered phase shift film having a phase shift layer made of ZrSiON, a metal layer made of ZrSi, and a reflectance reducing layer made of ZrSiON, sequentially from the transparent substrate side.
Further, a three-layer phase shift film having a phase shift layer made of MoSiON, a metal layer made of MoSi, and a reflectance reducing layer made of MoSiON can be mentioned in order from the transparent substrate side.
Based on these, the present invention includes an embodiment in which the material of each layer is replaced with the materials listed above as materials that can be selected in each layer.

In the phase shift film having a three-layer structure consisting of a phase shift layer made of ZrSiON, a metal layer made of ZrSi, and a reflectance reducing layer made of ZrSiON in order from the transparent substrate side, the present inventor has a metal layer made of ZrSi. When the film thickness is reduced (for example, 2.5 nm or more and less than 20 nm, for example, 10 nm), the transmittance increases, but the reflectance also increases. It was found that if the allowable range of reflectance is increased (for example, if the upper limit is increased to "20% or less"), the transmittance can be up to about 45%.
The present inventor has found that high transmittance can be up to about 30% when the low reflectance range (for example, 10% or less) is maintained. When maintaining a low reflectance range (for example, 10% or less), the film thickness of the metal layer made of ZrSi is suitable, for example, 20 nm or more and 35 nm or less.

Further, the present inventor, for example, in the above-mentioned ZrSi-based three-layer phase shift film, when the film thickness of the metal layer made of ZrSi is increased (for example, 40 to 60 nm), the normal transmittance (3% or more and 15%) is increased. It was found that less than, particularly 3% or more and 12% or less) and low transmittance (1% or more and less than 3%) are possible.

For example, in a three-layer phase shift film having a phase shift layer made of ZrSiON, a metal layer made of ZrSi, and a reflectance reducing layer made of ZrSiON in order from the transparent substrate side, the degree of oxidation of the phase shift layer made of ZrSiON. When is increased, the transmittance becomes high (the transmittance increases).
Further, for example, in the above, when the transmittance of the phase shift layer made of ZrSiON is increased (when adjusted to a high transmittance), the transmittance is increased accordingly. Further, at this time, it is possible to increase the film thickness of the metal layer made of ZrSi by the amount that the transmittance is increased.

Further, the present inventor has, for example, in a phase shift film having a three-layer structure in which a phase shift layer made of ZrSiON / a metal layer made of ZrSi / a reflectance reducing layer made of ZrSiON are sequentially formed from the transparent substrate side. Was replaced with CrOCN or MoSiON from ZrSiON, and it was found that the normal transmittance (for example, about 6%) could be controlled.

As described above, the combination of the phase shift layer made of ZrSiON, the reflectance reducing layer made of ZrSiON, and the metal layer made of ZrSi has a high transmittance of 15% or more and a predetermined transmittance wavelength dependence. The present inventor has found that it is possible to obtain a phase shift film having a transmittance of less than 4.0% and an exceptionally excellent transmittance wavelength dependence.

In the present invention, the phase shift film having a laminated structure in which the above-mentioned ZrSi-containing material layer (appropriately referred to as a ZrSi-based layer) is two layers, the ZrSi-based layer is three layers, and the ZrSi-based layer is a multilayer. included. The same applies to other metal silicide-based material layers. In the case of a phase shift film having a laminated structure in which ZrSi-based layers are multi-layered, the ZrSi-based material has the advantages of high chemical resistance, high wet etching rate, and good pattern cross-sectional shape.

There is a demand for a phase shift layer having a low transmittance of 2% or less in the wavelength range of 365 nm or more and 436 nm or less, and further having a transmittance of less than 2% and 1% or more.
For example, even if the transmittance of the phase shift layer is about 6%, the resist is exposed to the exposure light transmitted through the phase shift portion of the phase shift mask, and the resist is reduced by that amount. On the other hand, by fulfilling the above requirements, it is possible to further reduce the influence of the thinning of the resist film formed on the transferred body due to the exposure light transmitted through the phase shift portion of the phase shift mask.
In the present invention, in the two or more phase shift layers or the phase shift layer having a three-layer structure, for example, by controlling the thickness of the metal layer, or transmitting through the phase shift layer and the reflectance reducing layer. It was found that the above requirements can be achieved by changing to a material with a lower rate.

In the present invention, the phase shift layer has a two-layer structure consisting of a phase shift layer made of ZrSiON / a metal layer made of ZrSi sequentially from the transparent substrate side, or a phase shift layer made of ZrSiON / ZrSi sequentially from the transparent substrate side. In the phase shift layer having a three-layer structure as a reflectance reducing layer made of a metal layer / ZrSiON (may be abbreviated as ZiSi-based two layers or ZiSi-based three layers in the specification), the metal layer is replaced with TiSi from ZrSi. If so, the same thing as above is possible. The same can be applied to the case where the metal layer is replaced with a material of MoSi from ZrSi.

In the present invention, when the metal layer is replaced with MoSi from ZrSi in the ZiSi-based 2 layer or the ZiSi-based 3 layer, the same as above is possible. However, the etching rate of the metal layer changes.
In the present invention, when the reflectance reducing layer is replaced with MoSiON from ZrSiON in the ZiSi-based 2 layer or the ZiSi-based 3 layer, high transmittance cannot be maintained, but normal transmittance can be obtained. In other respects, the same can be done as above.

Hereinafter, the present invention will be described in more detail based on Examples and Comparative Examples. The following Examples 1 and 2 are examples of the present invention and do not limit the present invention.
Example 1 includes Examples 1-1 to 1-3.

(Example 1-1)
(Phase shift mask blank)
In Example 1-1, the phase shift mask blank having the structure of QZ (transparent substrate) / ZrSiON / ZrSi / ZrSiON will be described.
The phase shift film in the phase shift mask blank of Example 1-1 is a phase shift layer (ZrSiON, film thickness 73 nm), a metal layer (ZrSi, film thickness 30 nm), and a reflectance reducing layer arranged in order from the transparent substrate side. It is composed of (ZrSiON, film thickness 30 nm).
As the transparent substrate, a synthetic quartz glass substrate (QZ) having a size of 800 mm × 920 mm and a thickness of 10 mm was used. Both main surfaces of the transparent substrate are mirror-polished. Both main surfaces of the transparent substrate used in the following Examples and Comparative Examples are mirror-polished in the same manner.

The phase shift film in which the phase shift layer, the metal layer, and the reflectance reducing layer were laminated on the transparent substrate had a refractive index of 2.55 at a wavelength of 365 nm and an extinction coefficient of 0.127 at a wavelength of 365 nm.
The refractive index and extinction coefficient of the phase shift film were measured using n & k Analyzer 1280 (trade name) manufactured by n & k Technology.

The content of each element in the phase shift layer (ZrSiON) was 22 atomic% for Zr, 22 atomic% for Si, 14 atomic% for O, and 42 atomic% for N.
The content of each element in the metal layer (ZrSi) was 50 atomic% for Zr and 50 atomic% for Si.
The content of each element in the reflectance reducing layer (ZrSiON) was 17 atomic% for Zr, 17 atomic% for Si, 20 atomic% for O, and 46 atomic% for N.
The content of each of the above elements was measured by X-ray photoelectron spectroscopy (XPS). In the following Examples and Comparative Examples, the same device was used for measuring the element content.

Due to the three-layer structure described above, the phase shift film had a transmittance of 19.2% at a wavelength of 365 nm, 21.7% at a wavelength of 405 nm, and 23.1% at a wavelength of 436 nm. Further, in this phase shift film, the fluctuation range of the transmittance (transmittance wavelength dependence) was 3.9% in the wavelength range of 365 nm to 436 nm.

The phase difference of the phase shift film was 199.7 ° at a wavelength of 365 nm, 174.2 ° at a wavelength of 405 nm, and 160.3 ° at a wavelength of 436 nm due to the above-mentioned three-layer structure. Further, in this phase shift film, the fluctuation range of the phase difference was 39.4 ° in the wavelength range of 365 nm to 436 nm.

FIG. 4 shows the transmittance spectrum of the phase shift film of the phase shift mask crank of Example 1-1.
The transmittance and the phase difference were measured using MPM-100 (trade name) manufactured by Lasertec. In the following examples and comparative examples, the same apparatus was used for measuring the transmittance and the phase difference. The transmittance values in the examples and comparative examples are both Air-based values.

The phase shift film has a surface reflectance of 10.5% at a wavelength of 350 nm, 7.9% at a wavelength of 365 nm, 6.3% at a wavelength of 405 nm, and 6.2% at a wavelength of 413 nm. It was 5.7% at a wavelength of 436 nm. Further, in this phase shift film, the fluctuation range of the surface reflectance was 2.2% in the wavelength range of 365 nm to 436 nm. Further, in this phase shift film, the fluctuation range of the surface reflectance was 4.8% in the wavelength range of 350 nm to 436 nm.
FIG. 5 shows the surface reflectance spectrum of the phase shift film of the phase shift mask blank of Example 1-1.
The surface reflectance was measured using So1idSpec-3700 (trade name) manufactured by Shimadzu Corporation. In the following Examples and Comparative Examples, the same device was used for measuring the surface reflectance.

The phase shift film had a backside reflectance of 24.5% at a wavelength of 365 nm, 40.2% at a wavelength of 405 nm, and 44.4% at a wavelength of 436 nm. Further, in this phase shift film, the fluctuation range of the back surface reflectance was 20.0% in the wavelength range of 365 nm to 436 nm.
FIG. 6 shows the back surface reflectance spectrum of the phase shift film of the phase shift mask blank of Example 1-1.
The back surface reflectance was measured using So1idSpec-3700 (trade name) manufactured by Shimadzu Corporation. In the following Examples and Comparative Examples, the same device was used for measuring the back surface reflectance.

(Manufacturing of phase shift mask blank)
The phase shift mask blank of Example 1-1 was manufactured by the following method.
First, a synthetic quartz glass substrate, which is a transparent substrate, was prepared.
After that, the transparent substrate was carried into the sputtering chamber of the sputtering apparatus.
After that, 5.0 kW of sputter power was applied to the ZrSi target (Zr: Si = 1: 2) (atomic (%) ratio) arranged in the sputtering chamber, and a mixed gas of Ar gas, O2 gas and N2 gas was applied. Was introduced into the sputtering chamber, and a phase shift layer having a film thickness of 73 nm made of ZrSiON was formed on the main surface of the transparent substrate. Here, the mixed gas was introduced into the sputtering chamber so that the flow rates were 50 sccm for Ar, 5 sccm for O2, and 50 sccm for N2.
After that, a sputtering power of 2.0 kW was applied to the ZrSi target (Zr: Si = 1: 2) (atomic (%) ratio), and while introducing Ar gas into the sputtering chamber, a film made of ZrSi was applied on the phase shift layer. A metal layer having a thickness of 30 nm was formed. Here, Ar gas was introduced into the sputtering chamber so that the flow rate was 100 sccm.
After that, a sputtering power of 5.0 kW was applied to the ZrSi target (Zr: Si = 1: 2) (atomic (%) ratio), and a mixed gas of Ar gas, O2 gas and N2 gas was introduced into the sputtering chamber. , A reflectance reducing layer having a film thickness of 30 nm made of ZrSiON was formed on the metal layer. Here, the mixed gas was introduced into the sputtering chamber so that the flow rates were 50 sccm for Ar, 10 sccm for O2, and 50 sccm for N2.
After that, a transparent substrate on which a phase shift film composed of a phase shift layer (ZrSiON, film thickness 73 nm), a metal layer (ZrSi, film thickness 30 nm), and a reflectance reduction layer (ZrSiON, film thickness 30 nm) is formed is sputtered. It was taken out of the device and cleaned.

(Manufacturing of phase shift mask)
Using the above-mentioned phase shift mask blank, a phase shift mask was manufactured by the following method.
First, a resist film made of a novolak-based positive photoresist was formed on the phase-shift film of the above-mentioned phase-shift mask blank. At this time, the phase shift film was subjected to HMDS treatment, and then a resist film was formed.
Then, a predetermined pattern (1.8 μm line and space pattern) was drawn on the resist film using a laser beam having a wavelength of 413 nm using a laser drawing machine.
Then, the resist film was developed with a predetermined developer to form a resist film pattern on the phase shift film. At this time, it was not confirmed that the roughness of the edge portion of the resist film pattern cross section was deteriorated, which was considered to be caused by the influence of the standing wave.
Then, the phase shift film was etched by using the resist film pattern as a mask to form the phase shift film pattern. Each of the phase shift layer, the metal layer and the reflectance reducing layer constituting the phase shift film is formed of a zirconium silicide-based material containing zirconium (Zr) and silicon (Si). Therefore, the phase shift layer, the metal layer, and the reflectance reducing layer can be etched with the same etching solution. Here, as the etching solution for etching the phase shift film, a zirconium silicide etching solution obtained by diluting a mixed solution of hydrogen peroxide, ammonium fluoride, and phosphoric acid with pure water was used.
Then, the resist film pattern was peeled off using a resist stripping solution.

The phase shift film pattern cross section of the phase shift mask manufactured by using the above-mentioned phase shift mask blank was such that the mask characteristics were not affected.
The phase shift film pattern cross section of the phase shift mask was observed using an electron microscope (JSM7401F (trade name) manufactured by JEOL Ltd.). In the following examples and comparative examples, the same device was used for observing the phase shift film pattern cross section.

The CD variation of the phase shift film pattern of the phase shift mask manufactured by using the above-mentioned phase shift mask blank was 55 nm, which was good. The CD variation is the deviation width from the target line-and-space pattern (line pattern width = 1.8 μm, space pattern width: 1.8 μm).
The CD variation of the phase shift film pattern of the phase shift mask was measured using SIR8000 manufactured by Seiko Instruments Nanotechnology. In the following Examples and Comparative Examples, the same device was used for measuring the CD variation of the phase shift film pattern.

The phase shift mask blank and the phase shift mask described above satisfy the predetermined optical characteristics of the phase difference and the transmittance, and have a high transmittance (19.2%) at a wavelength of 365 nm, but have a transmittance of 365 nm or more. In the wavelength range of 436 nm or less, the transmittance wavelength dependence is excellent (4.0%), the front surface reflectance characteristics are also excellent (7.9% or less), and the back surface reflectance characteristics are also excellent (24.5% or more). , Each characteristic was combined. In addition, in response to the excellent characteristics of the phase shift mask, positional deviation during pattern transfer is suppressed, the resolution of the transfer pattern transferred onto the display device substrate is improved, and the pattern line width is 1.8 μm. It was confirmed that the line-and-space pattern of was transferred without the occurrence of a CD error. The pattern transfer step using the phase shift mask in the manufacturing process of the display device is a projection exposure of 1x exposure with a numerical aperture (NA) of 0.1, and the exposure light is i-line, h-line and g-line. It was a composite light containing. Hereinafter, the manufacturing process of the display device in Examples 1-2, 1-3, Example 2, and Comparative Example 1 was performed under these exposure conditions.

(Example 1-2)
(Phase shift mask blank)
In Example 1-2, the phase shift mask blank having the structure of QZ (transparent substrate) / ZrSiON / MoSi / ZrSiON will be described.
In Example 1-2, only the metal layer is different from the phase shift mask blank of Example 1-1.
The phase shift film in the phase shift mask blank of Example 1-2 is a phase shift layer (ZrSiON, film thickness 73 nm), a metal layer (MoSi, film thickness 10 nm), and a reflectance reducing layer arranged in order from the transparent substrate side. It is composed of (ZrSiON, film thickness 30 nm).

The value of the content of each element of the phase shift layer (ZrSiON) and the reflectance reduction layer (ZrSiON) is the same as that of Example 1-1.
The content of each element in the metal layer (MoSi) was 33 atomic% for Mo and 67 atomic% for Si.

Due to the above-mentioned three-layer structure of the phase shift film, the transmittance is lower than that of Example 1-1 and is within the range of the normal transmittance of 3% to 10%, and the transmittance of the phase shift film fluctuates. The width (transmittance wavelength dependence) was within 5.5% in the wavelength range of 365 nm to 436 nm.

Due to the above-mentioned three-layer structure, the phase shift film had a phase difference in the range of 160 ° to 200 ° at a wavelength of 365 nm.

The surface reflectance of the phase shift film was 10% or less in the wavelength range of 365 nm to 436 nm. Further, the surface reflectance of the phase shift film was 15% or less in the wavelength range of 350 nm to 436 nm.
The back surface reflectance of the phase shift film was also 20% or more in the wavelength range of 365 nm to 436 nm.

(Manufacturing of phase shift mask blank and phase shift mask)
In Example 1-2, 1.5 kW of sputtering power is applied to the MoSi target (Mo: Si = 1: 2) (atomic (%) ratio) at the time of film formation of the metal layer, and Ar gas is introduced into the sputtering chamber. At the same time, a metal layer having a film thickness of 10 nm made of MoSi was formed on the phase shift layer. Here, Ar gas was introduced into the sputtering chamber so as to have a flow rate of 120 sccm.
In other respects, the phase shift mask blank and the phase shift mask of Example 1-2 were manufactured by the same method as in Example 1-1.

The CD variation of the phase shift film pattern of the phase shift mask manufactured by using the above-mentioned phase shift mask blank was 62 nm, which was good. The above-mentioned phase shift mask blank and phase shift mask satisfy predetermined optical characteristics of phase difference and transmittance, are excellent in transmittance wavelength dependence, and are also excellent in front surface reflectance characteristics and back surface reflectance characteristics, and have each characteristic. It was a thing. In addition, in response to the excellent characteristics of the phase shift mask, positional deviation during pattern transfer is suppressed, the resolution of the transfer pattern transferred onto the display device substrate is improved, and the pattern line width is 1.8 μm. It was confirmed that the line-and-space pattern of was transferred without the occurrence of a CD error.

(Example 1-3)
In Examples 1-3, a phase shift mask blank having a light-shielding film made of QZ (transparent substrate) / ZrSiON / ZrSi / Cr-based material will be described.
In Examples 1-3, the phase shift mask blank of Example 1-1 is a phase shift film that does not form a reflectance reducing layer, and a light shielding film made of a Cr-based material having an antireflection function is formed on the phase shift film. The point is different.
The phase shift film in the phase shift mask blank of Example 1-3 is composed of a phase shift layer (ZrSiON, film thickness 130 nm) and a metal layer (MoSi, film thickness 10 nm) arranged in order from the transparent substrate side. .. The light-shielding film made of a Cr-based material formed on the phase-shift film is a light-shielding film having an antireflection function consisting of CrN (thickness 25 nm) / CrCN (thickness 70 nm) / CrON (thickness 25 nm). .. Due to the laminated structure of CrN / CrCN / CrON, the light-shielding film had a film surface reflectance of 10% or less at a wavelength of 413 nm of laser drawing light.

The phase shift film has a transmittance of about 12% at a wavelength of 365 nm due to the above-mentioned two-layer structure, and the fluctuation range of the transmittance of the phase shift film (transmittance wavelength dependence) is in the wavelength range of 365 nm to 436 nm. It was within 5.5%.

Due to the above-mentioned two-layer structure, the phase shift film had a phase difference in the range of 160 ° to 200 ° at a wavelength of 365 nm.
Further, in the phase shift mask blank of Example 1-3, the surface reflectance of the phase shift film is 10% or less at the wavelength of 413 nm of the laser drawing light, and the back surface reflectance of the phase shift film is a wavelength of 365 nm to 436 nm. In the region, it was 18% or more.

(Manufacturing of phase shift mask)
Using the above-mentioned phase shift mask blank, a phase shift mask was manufactured by the following method.
First, a resist film made of a novolak-based positive photoresist was formed on the light-shielding film of the phase shift mask blank described above. Then, a predetermined pattern (1.8 μm line and space pattern) was drawn on the resist film using a laser beam having a wavelength of 413 nm using a laser drawing machine.
Then, the resist film was developed with a predetermined developer to form a resist film pattern on the light-shielding film. At this time, it was not confirmed that the roughness of the edge portion of the resist film pattern cross section was deteriorated, which was considered to be caused by the influence of the standing wave.
Then, the light-shielding film is etched with a chromium etching solution containing second cerium nitrate ammonium nitrate and perchloric acid using the resist film pattern as a mask to form a light-shielding film pattern, and then the light-shielding film pattern is used as a mask. A phase shift film pattern was formed by etching with the zirconium silicide etching solution of Example 1-1.
Then, the resist film pattern was peeled off using a resist stripping solution, and further, the light-shielding film pattern was peeled off using a chromium etching solution.
The CD variation of the phase shift film pattern of the phase shift mask manufactured by using the above-mentioned phase shift mask blank was 56 nm, which was good.
The above-mentioned phase shift mask blank and phase shift mask satisfy predetermined optical characteristics of phase difference and transmittance, are excellent in transmittance wavelength dependence, and are also excellent in backside reflectance characteristics, and have each characteristic. .. In addition, in response to the excellent characteristics of the phase shift mask, positional deviation during pattern transfer is suppressed, the resolution of the transfer pattern transferred onto the display device substrate is improved, and the pattern line width is 1.8 μm. It was confirmed that the line-and-space pattern of was transferred without the occurrence of a CD error.

(Example 2)
In the second embodiment, the phase shift mask blank having the configuration of QZ (transparent substrate) / MoSiON / MoSi / MoSiON will be described.
The phase shift film in the phase shift mask blank of Example 2 is a phase shift layer (MoSiON, film thickness 100 nm), a metal layer (MoSi, film thickness 10 nm), and a reflectance reduction layer (MoSiON) arranged in order from the transparent substrate side. , Thickness 50 nm).

The phase shift film in which the phase shift layer, the metal layer, and the reflectance reducing layer were laminated on the transparent substrate had a refractive index of 2.06 at a wavelength of 365 nm and an extinction coefficient of 0.354 at a wavelength of 365 nm.

The content of each element in the phase shift layer (MoSiON) was 30 atomic% for Mo, 20 atomic% for Si, 20 atomic% for O, and 30 atomic% for N.
The content of each element in the metal layer (MoSi) was 33 atomic% for Mo and 67 atomic% for Si.
The content of each element in the reflectance reducing layer (MoSiON) was 30 atomic% for Mo, 20 atomic% for Si, 30 atomic% for O, and 20 atomic% for N ratio.

Due to the three-layer structure described above, the phase shift film had a transmittance of 4.7% at a wavelength of 365 nm, 7.0% at a wavelength of 405 nm, and 8.8% at a wavelength of 436 nm. Further, this phase shift film had a transmittance fluctuation range (transmittance wavelength dependence) of 4.1% in the wavelength range of 365 nm to 436 nm.
FIG. 7 shows the transmittance spectrum of the phase shift film of the phase shift mask crank of the second embodiment.

Due to the three-layer structure described above, the phase shift film had a phase difference of 177.1 ° at a wavelength of 365 nm, 159.0 ° at a wavelength of 405 nm, and 147.3 ° at a wavelength of 436 nm. Further, in this phase shift film, the fluctuation range of the phase difference was 29.8 ° in the wavelength range of 365 nm to 436 nm.

The phase shift film has a surface reflectance of 4.1% at a wavelength of 350 nm, 3.0% at a wavelength of 365 nm, 2.4% at a wavelength of 405 nm, and 2.6 at a wavelength of 413 nm. %, Which was 3.5% at a wavelength of 436 nm. Further, in this phase shift film, the fluctuation range of the surface reflectance was 1.1% in the wavelength range of 365 nm to 436 nm. Further, in this phase shift film, the fluctuation range of the surface reflectance was 1.7% in the wavelength range of 350 nm to 436 nm.
FIG. 8 shows the surface reflectance spectrum of the phase shift film of the phase shift mask blank of Example 2.
FIG. 9 shows the back surface reflectance spectrum of the phase shift film of the phase shift mask blank of Example 2.

The phase shift film had a backside reflectance of 19.6% at a wavelength of 365 nm, 23.0% at a wavelength of 405 nm, and 23.6% at a wavelength of 436 nm. Further, in this phase shift film, the fluctuation range of the back surface reflectance was 3.9% in the wavelength range of 365 nm to 436 nm.

The phase shift mask blank of Example 2 was manufactured by the following method.
First, a synthetic quartz glass substrate, which is a transparent substrate, was prepared. Both main surfaces of the transparent substrate are mirror-polished.
After that, the transparent substrate was carried into the sputtering chamber of the sputtering apparatus.
After that, 5.0 kW of spanter power was applied to the MoSi target (Mo: Si = 1: 4) (atomic (%) ratio) arranged in the sputter chamber, and a mixed gas of Ar gas, O2 gas and N2 gas was applied. Was introduced into the sputtering chamber, and a phase shift layer having a film thickness of 100 nm made of MoSiON was formed on the main surface of the transparent substrate. Here, the mixed gas was introduced into the sputtering chamber so that the flow rates were 60 sccm for Ar, 40 sccm for O2, and 50 sccm for N2.
After that, a sputtering power of 6.0 kW was applied to the MoSi target (Mo: Si = 1: 2) (atomic (%) ratio), and while introducing Ar gas into the sputtering chamber, a film made of MoSi was applied on the phase shift layer. A metal layer having a thickness of 10 nm was formed. Here, Ar gas was introduced into the sputtering chamber so that the flow rate was 100 sccm.
After that, a sputtering power of 5.0 kW was applied to the MoSi target (Mo: Si = 1: 4) (atomic (%) ratio), and a mixed gas of Ar gas, O2 gas and N2 gas was introduced into the sputtering chamber. , A reflectance reducing layer having a film thickness of 50 nm made of MoSiON was formed on the metal layer. Here, the mixed gas was introduced into the sputtering chamber so that the flow rates were 50 sccm for Ar, 50 sccm for O2, and 60 sccm for N2.
After that, a transparent substrate on which a phase shift film composed of a phase shift layer (MoSiON, film thickness 100 nm), a metal layer (MoSi, film thickness 10 nm), and a reflectance reduction layer (MoSiON, film thickness 50 nm) is formed is sputtered. It was taken out of the device and cleaned.

Using the above-mentioned phase shift mask blank, a phase shift mask was manufactured by the following method.
First, a resist film made of a novolak-based positive photoresist was formed on the phase-shift film of the above-mentioned phase-shift mask blank. At this time, the phase shift film was subjected to HMDS treatment, and then a resist film was formed.
Then, a predetermined pattern (1.8 μm line and space pattern) was drawn on the resist film using a laser beam having a wavelength of 413 nm using a laser drawing machine.
Then, the resist film was developed with a predetermined developer to form a resist film pattern on the phase shift film. At this time, it was not confirmed that the roughness of the edge portion of the resist film pattern cross section was deteriorated, which was considered to be caused by the influence of the standing wave.
Then, the phase shift film was etched by using the resist film pattern as a mask to form the phase shift film pattern. Each of the phase shift layer, the metal layer and the reflectance reducing layer constituting the phase shift film is formed of a molybdenum silicide-based material containing molybdenum (Mo) and silicon (Si). Therefore, the phase shift layer, the metal layer, and the reflectance reducing layer can be etched with the same etching solution. Here, as the etching solution for etching the phase shift film, a molybdenum silicide etching solution obtained by diluting a mixed solution of ammonium hydrogenfluoride and hydrogen peroxide with pure water was used.
Then, the resist film pattern was peeled off using a resist stripping solution.

The phase shift film pattern cross section of the phase shift mask manufactured by using the above-mentioned phase shift mask blank was such that the mask characteristics were not affected.

The CD variation of the phase shift film pattern of the phase shift mask manufactured by using the above-mentioned phase shift mask blank was 63 nm, which was good. The CD variation is the deviation width from the target line-and-space pattern (line pattern width: 1.8 μm, space pattern width: 1.8 μm).

The above-mentioned phase shift mask blank and phase shift mask have excellent transmittance wavelength dependence (4.1%) in the wavelength range of 365 nm or more and 436 nm or less while satisfying predetermined optical characteristics of phase difference and transmittance (4.1%). At the same time, the front surface reflectance characteristics were also excellent (3.5% or less), the back surface reflectance characteristics were also excellent (19.64% or more), and each characteristic was combined. In addition, in response to the excellent characteristics of the phase shift mask, positional deviation during pattern transfer is suppressed, the resolution of the transfer pattern transferred onto the display device substrate is improved, and the pattern line width is 1.8 μm. It was confirmed that the line-and-space pattern of was transferred without the occurrence of a CD error.

(Comparative Example 1)
The phase shift film in the phase shift mask blank of Comparative Example 1 is composed of only a phase shift layer (CrOCN, film thickness 122 nm). The phase shift mask blank of Comparative Example 1 is different from the phase shift mask blank of the above-described embodiment in that the phase shift film does not include the metal layer and the reflectance reducing layer.
The phase shift film in the phase shift mask blank of Comparative Example 1 was formed under the following film forming conditions.
The content of each element in the phase shift film (CrOCN) was 44 atomic% for Cr, 8 atomic% for C, 30 atomic% for O, and 18 atomic% for N.
The phase shift film had a transmittance of 4.6% at a wavelength of 365 nm, 8.0% at a wavelength of 405 nm, and 11.0% at a wavelength of 436 nm. Further, in this phase shift film, the fluctuation range of the transmittance (transmittance wavelength dependence) was 6.4% in the wavelength range of 365 nm to 436 nm.
Due to the one-layer structure described above, the phase shift film has a phase difference of 179.6 ° at a wavelength of 365 nm, 164.7 ° at a wavelength of 405 nm, 161.7 ° at a wavelength of 413 nm, and a wavelength of 436 nm. It was 153.1 °. Further, in this phase shift film, the fluctuation range of the phase difference was 26.5 ° in the wavelength range of 365 nm to 436 nm.
FIG. 10 shows the transmittance spectrum of the phase shift film of the phase shift mask blank of Comparative Example 1.
Further, the phase shift film has a surface reflectance of 24.0% at a wavelength of 365 nm, 25.1% at a wavelength of 405 nm, 25.3% at a wavelength of 413 nm, and 26. At a wavelength of 436 nm. It was 0%. Further, the phase shift film had a fluctuation range of surface reflectance of 2.0% in the wavelength range of 365 nm to 436 nm.
FIG. 11 shows the surface reflectance spectrum of the phase shift film of the phase shift mask blank of Comparative Example 1.
Further, the phase shift film had a back surface reflectance of 17.9% at a wavelength of 365 nm, 19.9% at a wavelength of 405 nm, and 20.3% at a wavelength of 436 nm. Further, the phase shift film had a fluctuation range of the back surface reflectance of 2.4% in the wavelength range of 365 nm to 436 nm.
FIG. 12 shows the back surface reflectance spectrum of the phase shift film of the phase shift mask blank of Comparative Example 1.
(Manufacturing of phase shift mask blank)
The phase shift mask blank of Comparative Example 1 was manufactured by the following method.
First, a synthetic quartz glass substrate, which is a transparent substrate, was prepared.
After that, the transparent substrate was carried into the sputtering chamber of the sputtering apparatus.
After that, a sputtering power of 3.5 kW is applied to the chrome target arranged in the sputtering chamber, and a mixed gas of Ar gas, N2 gas and CO2 gas is introduced into the sputtering chamber to introduce a phase shift film having a thickness of 122 nm made of CrOCN. Was formed. Here, the mixed gas was introduced into the sputtering chamber so that Ar had a flow rate of 46 sccm, N2 had a flow rate of 32 sccm, and CO2 had a flow rate of 18.5 sccm.
Then, the transparent substrate on which the phase shift film was formed was taken out from the sputtering apparatus and washed.
(Manufacturing of phase shift mask)
Using the above-mentioned phase shift mask blank, a phase shift mask was manufactured by the following method.
First, a resist film made of a novolak-based positive photoresist was formed on the phase-shift film of the above-mentioned phase-shift mask blank. Then, a predetermined pattern (1.8 μm line and space pattern) was drawn on the resist film using a laser beam having a wavelength of 413 nm using a laser drawing machine. Then, the resist film was developed with a predetermined developer to form a resist film pattern on the phase shift film.
Then, using the resist film pattern as a mask, the phase shift film is etched with a chromium etching solution containing second cerium nitrate ammonium nitrate and perchloric acid to form a phase shift film pattern, and then a resist stripping solution is used. The resist film pattern was peeled off.
The CD variation of the phase shift film pattern of the phase shift mask manufactured by using the above-mentioned phase shift mask blank is 90 nm, which is a level required for the phase shift mask used in the manufacture of high-resolution, high-definition display devices. Did not reach.
Since the phase shift mask according to Comparative Example 1 described above has a large CD variation and a high reflectance on the surface of the phase shift film pattern with respect to the exposure light, the phase shift mask described above is used to display high resolution and high definition. The device could not be manufactured.

As described above, the present invention has been described in detail based on the embodiments and examples, but the present invention is not limited thereto. It is clear that a person having ordinary knowledge in the relevant field can make modifications and improvements within the technical idea of the present invention.

10 Phase shift mask blank, 20 Transparent substrate, 30 Phase shift film, 31 Phase shift layer, 32 Reflectance reduction layer, 33 Metal layer, 40 Light-shielding film pattern, 45 Light-shielding film, 46 Light-shielding layer, 47 Surface reflectance reduction layer

Claims (17)

In a phase shift mask blank for manufacturing display devices
A transparent substrate and a phase shift film formed on the transparent substrate are provided.
The phase shift film is composed of two or more laminated films.
The phase shift film mainly includes a phase shift layer having a function of adjusting the transmittance and a phase difference with respect to exposure light, and a metal layer having a function of adjusting the transmittance wavelength dependence in the wavelength range of 365 nm or more and 436 nm or less. Have at least
The phase shift film has predetermined optical characteristics in terms of the transmittance and phase difference of the phase shift film with respect to the exposure light.
The phase shift layer is made of a material containing a metal, silicon, and one or more elements selected from nitrogen and oxygen.
The metal layer is made of a material composed of metal and silicon, or a material composed of metal and silicon, and at least one of carbon, fluorine, nitrogen, and oxygen.
The content of the metal contained in the metal layer is higher than the content of the metal contained in the phase shift layer, or the total content of the metal and silicon contained in the metal layer is contained in the phase shift layer. More than the total content of metal and silicon
The phase shift mask is a phase shift mask blank having a transmittance wavelength dependence of 5.5% or less in a wavelength range of 365 nm or more and 436 nm or less. The metal constituting the phase shift layer is any of Zr, Mo, Ti, Ta, and W.
It ’s one of them,
The phase shift mask blank according to claim 1, wherein the metal constituting the metal layer is any one of Zr, Mo, Ti, Ta, and W. The phase shift mask blank according to claim 1 or 2, wherein the metal constituting each of the phase shift layer and the metal layer is the same metal. In a phase shift mask blank for manufacturing display devices
A transparent substrate and a phase shift film formed on the transparent substrate are provided.
The phase shift film is mainly a phase shift layer having a function of adjusting the transmittance and a phase difference with respect to the exposure light, and light incident on the upper side of the phase shift layer and incident from the surface side of the phase shift film. A function of adjusting the transmittance wavelength dependence in the wavelength range of 365 nm or more and 436 nm or less, which is arranged between the phase shift layer and the reflectance reducing layer, and a reflectance reducing layer having a function of reducing the transmittance with respect to the light. Has a metal layer to have
Due to the laminated structure of the phase shift layer, the metal layer and the reflectance reducing layer, the transmittance and phase difference of the phase shift film with respect to the exposure light have predetermined optical characteristics.
The phase shift layer is made of a material containing metal, silicon, and at least one of nitrogen and oxygen.
The metal layer is made of a material composed of metal and silicon, or a material composed of metal and silicon, and at least one of carbon, fluorine, nitrogen, and oxygen.
The content of the metal contained in the metal layer is higher than the content of the metal contained in the phase shift layer, or the total content of the metal and silicon contained in the metal layer is contained in the phase shift layer. More than the total content of metal and silicon
The phase shift mask is a phase shift mask blank having a transmittance wavelength dependence of 5.5% or less in a wavelength range of 365 nm or more and 436 nm or less. The metal constituting the phase shift layer is any one of Zr, Mo, Ti, Ta, and W.
The metal constituting the metal layer is any one of Zr, Mo, Ti, Ta, and W, and the metals constituting the reflectance reducing layer are Zr, Mo, Cr, Ti, Ta, and The phase shift mask blank according to claim 4 , wherein the phase shift mask blank is any one of W. A claim characterized in that the metal constituting each of the phase shift layer and the metal layer, or the metal constituting each layer of the phase shift layer, the metal layer and the reflectance reducing layer is the same metal. Item 4. The phase shift mask blank according to Item 4. The reflectance reducing layer is composed of a material containing metal and silicon and at least one of nitrogen, oxygen and carbon, or a material containing metal and at least one of nitrogen, oxygen and carbon. The phase shift mask blank according to any one of claims 4 to 6. Wherein the phase shift film, the surface reflectance of the phase shift film for light incident from the front surface side of the phase shift film, claim 4, characterized in that 10% or less in the wavelength region of 365nm~436nm 7. The phase shift mask blank according to any one of 7. According to claim 4, the phase shift film has a surface reflectance of 15% or less in a wavelength range of 350 nm to 436 nm with respect to light incident from the surface side of the phase shift film. 8. The phase shift mask blank according to any one of 8. The phase shift mask blank according to any one of claims 1 to 9, wherein the phase shift film has a transmittance in the range of 1% or more and 50% or less at a wavelength of 365 nm. The phase shift mask blank according to any one of claims 1 to 10, wherein the phase shift film has a transmittance in the range of 15% or more and 50% or less at a wavelength of 365 nm. The back surface reflectance of the phase shift film with respect to the light incident from the back surface side of the transparent substrate is 3.
The phase shift mask blank according to any one of claims 1 to 11 , wherein the phase shift mask blank is 20% or more in the wavelength range of 65 nm to 436 nm. The phase shift mask blank according to any one of claims 1 to 12 , further comprising a light-shielding film formed on the phase shift film. The light-shielding film is characterized in that the film surface reflectance of the light-shielding film with respect to light incident from the surface side of the light-shielding film is 15% or less in a wavelength range of 350 nm to 436 nm.
13. The phase shift mask blank according to 13. In the method of manufacturing a phase shift mask for manufacturing a display device,
On the phase shift film of the phase shift mask blank according to any one of claims 1 to 12,
A step of forming a resist film and forming a resist film pattern by a drawing process using a laser beam having any wavelength selected from the wavelength range of 350 nm to 436 nm and a development process.
A method for manufacturing a phase shift mask, which comprises a step of etching the phase shift film using the resist film pattern as a mask to form a phase shift film pattern. In the method of manufacturing a phase shift mask for manufacturing a display device,
A resist film is formed on the light-shielding film of the phase shift mask blank according to claim 13 or 14 , and drawing processing and development using a laser beam having any wavelength selected from the wavelength range of 350 nm to 436 nm are used. The process of forming a resist film pattern by processing and
A step of forming the light-shielding film pattern by etching the light-shielding film using the resist film pattern as a mask.
A method for manufacturing a phase shift mask, which comprises a step of etching a phase shift film using the light shielding film pattern as a mask to form a phase shift film pattern. In the manufacturing method of display devices
A phase shift mask obtained by the method for manufacturing a phase shift mask according to claim 15 or 16 is arranged facing the resist film on a substrate with a resist film having a resist film formed on the substrate. Mask placement process and
A method for manufacturing a display device, which comprises a pattern transfer step of irradiating the phase shift mask with composite exposure light including i-line, h-line, and g-line to transfer the phase-shift film pattern.

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