KR102503789B1 - Appratus for fabricating semiconductor device - Google Patents

Abstract

상기 식 1에서, 상기 XM1은 상기 위상 반전층에 상기 일반 모드 XRD 분석이 진행될 때, 측정된 X선 강도의 최대값이고, 상기 XQ1은 상기 투명 기판의 하면에 상기 일반 모드 XRD 분석이 진행될 때, 측정된 X선 강도의 최대값이다.Embodiments relate to an apparatus for manufacturing a semiconductor device and a blank mask, comprising: a light source; and a photomask through which light from the light source is incident, selectively transmits the incident light, and emits the incident light to a semiconductor wafer, wherein the photomask includes a transparent substrate; a phase inversion layer disposed on the transparent substrate; and a light blocking layer disposed on the phase shift layer, wherein the photomask is analyzed by normal mode XRD, and in the normal mode XRD analysis, the maximum peak of X-ray intensity measured after reflection in the direction of the phase shift layer is 2θ Is located between 15 ° and 30 °, and the maximum peak of the X-ray intensity measured after reflection in the direction of the transparent substrate in the normal mode XRD analysis is located between 15 ° and 30 °, 2θ is located between 15 ° and 30 °, and is represented by Equation 1 below An apparatus for manufacturing a semiconductor device having a first amorphous index (AI1) of 0.9 to 1.1.
[Equation 1]

In Equation 1, XM1 is the maximum value of X-ray intensity measured when the normal mode XRD analysis is performed on the phase shift layer, and XQ1 is the normal mode XRD analysis on the lower surface of the transparent substrate. When the normal mode XRD analysis is performed, It is the maximum value of the measured X-ray intensity.

Description

Semiconductor device manufacturing device

An embodiment relates to an apparatus for manufacturing a semiconductor device and a blank mask.

Due to high integration of semiconductor devices and the like, miniaturization of circuit patterns of semiconductor devices is required. For this reason, the importance of lithography technology, which is a technology of developing a circuit pattern using a photomask on the surface of a wafer, is becoming more prominent.

In order to develop a miniaturized circuit pattern, a short wavelength of an exposure light source used in an exposure process is required. An exposure light source recently used includes an ArF excimer laser (wavelength: 193 nm) and the like.

Meanwhile, the photomask includes a binary mask, a phase shift mask, and the like.

The binary mask has a configuration in which a light blocking layer pattern is formed on a transparent substrate. The binary mask exposes the pattern on the resist film on the surface of the wafer by transmitting exposure light through a transmission portion not including a light blocking layer and blocking exposure light by blocking exposure light including a light blocking layer. However, as the pattern of the binary mask is miniaturized, a problem may occur in fine pattern development due to diffraction of light generated at the edge of the transmission portion during exposure.

Phase shift masks include a Levenson type, an outrigger type, and a half-tone type. Among them, the half-tone phase shift mask has a configuration in which a pattern formed of a semi-transmissive film is formed on a transparent substrate. In the half-tone phase shift mask, on the surface where the pattern is formed, the transmissive portion not including the semi-transmissive layer transmits exposure light, and the transmissive portion including the semi-transmissive layer transmits attenuated exposure light. The attenuated exposure light has a phase difference compared to the exposure light passing through the transmission part. Due to this, the diffracted light generated at the edge of the transmission part is canceled by the exposure light passing through the semi-transmission part, so that the phase shift mask can form a more sophisticated fine pattern on the wafer surface.

Related prior art includes Korean Patent Registration No. 10-1360540, US Patent Publication No. 2004-0115537, and Japanese Patent Publication No. 2018-054836.

Embodiments are intended to provide an apparatus for manufacturing a semiconductor device and a blank mask capable of easily forming fine patterns.

An apparatus for manufacturing a semiconductor device according to an embodiment includes a light source; and a photomask through which light from the light source is incident, selectively transmits the incident light, and emits the incident light to a semiconductor wafer.

A photo mask according to an embodiment includes a transparent substrate; a phase inversion layer disposed on the transparent substrate; and a light blocking layer disposed on the phase inversion layer.

The photomask is analyzed by normal mode XRD. When the normal mode XRD analysis is performed, the maximum peak of the X-ray intensity measured after reflection in the direction of the phase shift layer is located between 15° and 30° at 2θ, and when the normal mode XRD analysis is performed, the lower surface of the transparent substrate The X-ray intensity measured after reflection in the direction has a maximum value between 2θ of 15 ° and 30 °, and the photomask has a first amorphous index (AI1) represented by Equation 1 below of 0.98 to 1.02.

[Equation 1]

In Equation 1, XM1 is the maximum value of X-ray intensity measured when the normal mode XRD analysis is performed on the phase shift layer, and XQ1 is the normal mode XRD analysis on the lower surface of the transparent substrate. When the normal mode XRD analysis is performed, It is the maximum value of the measured X-ray intensity.

In one embodiment, the phase shift layer includes a phase difference adjustment layer disposed on the transparent substrate and a protective layer disposed on the phase difference adjustment layer. The phase shift layer includes a transition metal, silicon, oxygen, and nitrogen. The retardation adjustment layer may contain 40 to 60 atomic % of nitrogen, and the protective layer may contain 20 to 40 atomic % of nitrogen.

The passivation layer includes a region in which the ratio of the nitrogen content to the oxygen content in the thickness direction is 0.4 to 2, and the region has a thickness of 30 to 80% when the total thickness of the passivation layer is taken as 100%.

In one embodiment, when the thickness of the phase shift layer is 100%, the thickness of the protective layer is 4 to 9%, the thickness of the protective layer is 25 Å or more and 80 Å or less, and the retardation adjustment layer has a refractive index of 2 to 9%. 4, and the extinction coefficient is 0.3 to 0.7.

In one embodiment, the light blocking layer includes chromium and nitrogen, contains 44 to 60 atomic % of the chromium, and has a total optical concentration of 3 or more from the lower surface of the phase shift layer to the upper surface of the light blocking layer.

In one embodiment, the photomask is analyzed by fixed mode XRD, and in the fixed mode XRD analysis, the first peak, which is the maximum peak of the X-ray intensity measured after reflection in the direction of the phase shift layer, has a 2θ of 15° to 25° The second peak, which is the maximum peak of the X-ray intensity measured after reflection in the direction of the transparent substrate in the fixed mode XRD analysis, is located between 15 ° and 25 ° in 2θ, and the photomask is expressed by Equation 2 below The displayed second amorphous index (AI2) is 0.9 to 1.1.

[Equation 2]

In Equation 2, XM2 is the intensity value of the first peak, and XQ2 is the intensity value of the second peak.

In one embodiment, the photomask has a third amorphous index (AI3) of 0.9 to 1.1 represented by Equation 3 below.

[Equation 3]

In Equation 3, AM1 is the area in the region where 2θ is between 15° and 30° in the X-ray intensity graph measured after reflection when normal mode XRD analysis is performed on the phase shift layer, and AQ1 is the transparent When normal mode XRD analysis is performed on the lower surface of the substrate, it is the area in the region where 2θ is between 15° and 30° in the X-ray intensity graph measured after reflection.

In one embodiment, the photomask has a fourth amorphous index (AI4) of 0.9 to 1.1 represented by Equation 4 below.

[Equation 4]

In Equation 4, XM4 is the reflected X-ray intensity when 2θ is 43° in the normal mode XRD analysis performed on the phase shift layer, and XQ4 is the reflected X-ray intensity in the normal mode XRD analysis performed on the lower surface of the transparent substrate. , is the reflected X-ray intensity when 2θ is 43°.

A blank mask according to an embodiment includes a transparent substrate; and a phase shift layer disposed on the transparent substrate, wherein the photomask is analyzed by normal mode XRD, and in the normal mode XRD analysis, a maximum peak of X-ray intensity measured after reflection in a direction of the phase shift layer is 2θ Is located between 15 ° and 30 °, the maximum peak of the X-ray intensity measured after reflection in the direction of the transparent substrate in the normal mode XRD analysis is located between 15 ° and 30 °, 2θ is located between 15 ° and 30 °, and the photo mask is The first amorphous index (AI) represented by 1 is 0.98 to 1.02.

A blank mask according to an embodiment includes a transparent substrate; a phase inversion layer disposed on the transparent substrate; and a light blocking layer disposed on the phase inversion layer. When the normal mode XRD analysis is performed through the light-blocking layer, the X-ray intensity measured after reflection has a maximum value between 15° and 30° in 2θ, and when the XRD analysis is performed through the lower surface of the transparent substrate , X-ray intensity measured after reflection has a maximum value between 2θ of 15° and 30°, and the photomask has a fifth amorphous index (AI5) of 0.9 to 0.97 represented by Equation 5 below.

[Equation 5]

In Equation 5, XC1 is the maximum value of X-ray intensity measured through the light blocking layer, and XQ1 is the maximum value of X-ray intensity measured through the lower surface of the transparent substrate.

In one embodiment, the blank mask may have a sixth amorphous index (AI6) of 1.05 to 1.4 represented by Equation 6 below.

[Equation 6]

In Equation 6, XC4 is the reflected X-ray intensity when 2θ is 43° when the normal mode XRD analysis is performed in the direction of the light blocking layer, and XQ4 is the normal mode XRD in the direction of the lower surface of the transparent substrate. When the analysis proceeds, it is the reflected X-ray intensity when 2θ is 43°.

Since the first amorphous index has the above range, the phase shift layer and the transparent substrate have very similar crystal properties.

In addition, since the second amorphous index has the above range, the phase shift layer and the transparent substrate have very similar crystal properties.

In addition, since the third amorphous index has the above range, the phase shift layer and the transparent substrate have very similar crystal properties.

In addition, since the fourth amorphous index has the above range, the phase shift layer and the transparent substrate have very similar crystal properties.

Accordingly, optical distortion due to a difference in crystal characteristics between the phase shift layer and the transparent substrate may be minimized. That is, since the phase shift layer and the transparent substrate have similar crystal characteristics according to XRD analysis, the photomask may have improved optical performance.

In particular, since the transparent substrate and the phase shift layer have similar crystal characteristics, optical distortion generated at the interface between the transparent substrate and the phase shift layer is reduced when the transparent substrate and the phase shift layer directly contact each other. It can be.

In addition, since the fifth amorphous index has the above range, the light blocking layer and the transparent substrate have different crystal characteristics.

Since the sixth amorphous index has the above range, the light blocking layer and the transparent substrate have different crystal characteristics.

Accordingly, the light blocking layer may have improved light blocking performance.

Accordingly, the apparatus for manufacturing a semiconductor device according to the embodiment can reduce process errors due to optical distortion in exposure and development processes. Therefore, the apparatus for manufacturing a semiconductor device according to the embodiment can easily manufacture a semiconductor device having improved fine line width characteristics.

1 is a schematic diagram showing an exposure apparatus according to an exemplary embodiment.
2 is a cross-sectional view illustrating a photomask according to an exemplary embodiment.
3 and 4 are cross-sectional views each illustrating a blank mask according to an exemplary embodiment.
5 is a schematic diagram showing a normal mode XRD analysis process.
6 is a schematic diagram showing a fixed mode XRD analysis process.
7 is a diagram illustrating X-ray intensities measured by performing normal mode XRD analysis on a phase shift layer in a blank mask according to an exemplary embodiment.
8 is a diagram illustrating X-ray intensities measured by performing normal mode XRD analysis on a transparent substrate in a blank mask according to an exemplary embodiment.
9 is a diagram illustrating X-ray intensities measured by performing normal mode XRD analysis on a light blocking layer in a blank mask according to an exemplary embodiment.
10 is a diagram illustrating X-ray intensities measured by performing fixed mode XRD analysis on a phase shift layer in a blank mask according to an embodiment.
11 is a diagram illustrating X-ray intensities measured by performing fixed mode XRD analysis on a transparent substrate in a blank mask according to an embodiment.
12 is a diagram illustrating X-ray intensities measured by performing fixed mode XRD analysis on a light blocking layer in a blank mask according to an exemplary embodiment.

Hereinafter, embodiments will be described in detail so that those skilled in the art can easily implement them. However, implementations may be implemented in many different forms and are not limited to the embodiments described herein.

As used herein, the terms "about," "substantially," and the like are used in a sense at or approximating that number when manufacturing and material tolerances inherent in the stated meaning are given, and are intended to assist in the understanding of embodiments. Accurate or absolute figures are used to prevent undue exploitation by unscrupulous infringers of the stated disclosure.

Throughout this specification, the term "combination of these" included in the expression of the Markush form means a mixture or combination of one or more selected from the group consisting of the components described in the expression of the Markush form, and the components It means including one or more selected from the group consisting of.

Throughout this specification, reference to "A and/or B" means "A, B, or A and B".

Throughout this specification, terms such as “first” and “second” or “A” and “B” are used to distinguish the same terms from each other unless otherwise specified.

In this specification, the meaning that B is located on A means that B is located on A or that B is located on A while another layer is located therebetween, and B is located so as to come into contact with the surface of A It is not construed as being limited to

In this specification, a singular expression is interpreted as a meaning including a singular number or a plurality interpreted in context unless otherwise specified.

In this specification, the drawings are presented for explanation of embodiments, and some of them may be exaggerated or omitted, and are not displayed according to scale.

In this specification, the transmissive portion TA refers to a region on the surface of a photomask on which a pattern is formed on a transparent substrate that does not substantially include a phase shift layer and transmits exposure light, and the transflective portion NTA refers to a region that substantially transmits exposure light. It refers to a region through which attenuated exposure light is transmitted, including (see FIG. 2).

A process of manufacturing a semiconductor device includes a process of forming a designed pattern by forming an exposure pattern on a semiconductor wafer. Specifically, when a photo mask including a designed pattern is placed on a semiconductor wafer having a resist layer coated thereon, and exposed through a light source, the resist layer of the semiconductor wafer forms the designed pattern after treatment with a developing solution. .

With the high integration of semiconductors, more miniaturized circuit patterns are required. In order to form a miniaturized pattern on a semiconductor wafer, exposure light having a shorter wavelength than conventionally applied exposure light may be applied. An example of exposure light for miniaturized pattern formation is an ArF excimer laser (wavelength: 193 nm).

Accordingly, films included in the photomask to form patterns are required to have improved optical characteristics.

In addition, a light source generating short-wavelength exposure light may require high output. Such a light source may increase the temperature of a photo mask included in a semiconductor device manufacturing apparatus in an exposure process.

Accordingly, the films that are included in the photomask and form patterns may exhibit characteristics in which physical properties, such as thickness and height, change according to temperature changes. Films included in the photomask to form patterns are also required to have improved thermal characteristics.

The entirety of the photomask is not made of the same material, but has a multilayer structure of at least two layers in cross section. Therefore, the characteristics of the blank mask, which is a laminated body including the phase shift film and the transparent substrate, also affect the physical properties of the photomask, and in some cases undergo oxidation treatment and heat treatment during the manufacturing process, so that the characteristics and completion of the initially laminated material itself It also shows a difference between the characteristics of the blank mask.

Crystal characteristics of each layer included in the photomask may be appropriately adjusted to improve optical and thermal characteristics of each layer included in the photomask.

According to the inventors of the embodiment, the temperature of the photomask is increased by a light source generating short-wavelength exposure light by adjusting the crystal characteristics of the films included in the photomask in the semiconductor device manufacturing apparatus within a certain range, or the difference in optical properties of each layer is affected. The embodiment was completed by experimentally confirming that the deterioration of the resolution of the pattern exposed on the resulting wafer can be substantially suppressed.

Hereinafter, implementations are described in more detail.

1 is a schematic diagram showing an exposure apparatus according to an exemplary embodiment. 2 is a cross-sectional view illustrating a photomask according to an exemplary embodiment. 3 and 4 are cross-sectional views each illustrating a blank mask according to an exemplary embodiment. 5 is a schematic diagram showing a normal mode XRD analysis process. 6 is a schematic diagram showing a fixed mode XRD analysis process. 7 is a diagram illustrating X-ray intensities measured by performing normal mode XRD analysis on a phase shift layer in a blank mask according to an exemplary embodiment. 8 is a diagram illustrating X-ray intensities measured by performing normal mode XRD analysis on a transparent substrate in a blank mask according to an exemplary embodiment. 9 is a diagram illustrating X-ray intensities measured by performing normal mode XRD analysis on a light blocking layer in a blank mask according to an exemplary embodiment. 10 is a diagram illustrating X-ray intensities measured by performing fixed mode XRD analysis on a phase shift layer in a blank mask according to an embodiment. 11 is a diagram illustrating X-ray intensities measured by performing fixed mode XRD analysis on a transparent substrate in a blank mask according to an embodiment. 12 is a diagram illustrating X-ray intensities measured by performing fixed mode XRD analysis on a light blocking layer in a blank mask according to an embodiment.

Semiconductor device manufacturing equipment

Referring to FIG. 1 , an apparatus for manufacturing a semiconductor device according to an exemplary embodiment includes a light source, an optical system, and a photomask. The optical system includes a condensing lens and a projection lens. An apparatus for manufacturing a semiconductor device according to an embodiment is a photolithography system.

The light source 10a is a device capable of generating short-wavelength exposure light. The exposure light may be light having a wavelength of 200 nm or less. The exposure light may be ArF light having a wavelength of 193 nm.

The light source generates light. The light source may be an ArF lamp. The light source may generate ultraviolet light. A wavelength of light generated from the light source may be about 193 nm.

The condensing lens 20a condenses the light from the light source onto the photo mask.

The photo mask 30a selectively transmits the light from the light source and emits it to the semiconductor wafer. In more detail, the light emitted from the condensing lens is selectively transmitted through the photo mask, and the selectively transmitted light is emitted to the projection lens 40a. The projection lens focuses the light incident from the photo mask and emits it to the semiconductor wafer 50a.

In a semiconductor device manufacturing apparatus, the projection lens may be positioned between a photomask and a semiconductor wafer. The projection lens has a function of reducing the shape of a circuit pattern on a photomask and transferring it onto a semiconductor wafer. The projection lens is not limited as long as it can be generally applied to an ArF semiconductor wafer exposure process. Illustratively, the projection lens may be a lens made of calcium fluoride (CaF ₂ ).

The semiconductor wafer may be a semiconductor substrate including a photoresist layer on top. The light selectively transmitted by the photo mask and the optical system may develop the semiconductor wafer. In more detail, light selectively transmitted by the photo mask and the optical system may develop the photoresist layer. That is, a photolithography process may be performed by the light source, the optical system, and the photomask.

photomask

2, the photomask includes a transparent substrate 10, a phase shift layer 20 disposed on the transparent substrate 10, and a light blocking layer 30 disposed on the phase shift layer 20. ).

The transparent substrate 10 serves to transmit exposure light to a thin film formed on the transparent substrate 10 .

The phase shift layer 20 in the photomask 200 may include a pattern to be transferred. The light blocking layer 30 in the photomask 200 may include a preset pattern.

The phase shift layer 20 may transmit only a portion of the exposure light passing through the phase shift layer 20 and improve the resolution of the developed pattern by adjusting the phase difference of the exposure light partially transmitted.

The light blocking layer 30 may block transmission of exposure light reaching the surface of the light blocking layer 30 .

The photomask 200 may be made of a blank mask 100 to be described below.

A detailed description of the layer structure, optical properties, composition, and sputtering method and patterning method of the transparent substrate 10, the phase shift layer 20, and the light blocking layer 30 in the photomask 200 will be described below in the blank mask and photo mask layer 200. Since it overlaps with the description of the mask manufacturing method, it will be omitted.

Optical characteristics of the phase shift layer 20 are determined according to various factors such as the composition of elements constituting the film, the density of the film, and the thickness of the film. Therefore, in order to maximize the resolution of a pattern to be developed on a semiconductor wafer, the phase shift layer 20 is designed and deposited in consideration of the above factors. However, the temperature of the phase shift layer 20 may increase due to heat generated from a light source during an exposure process, and the thickness value and stress of the phase shift layer 20 may vary due to the heat.

Elements constituting the phase inversion layer 20, content of each element, magnetic field strength in the sputtering process, substrate rotation speed, voltage applied to the target, atmospheric gas composition, sputtering temperature, post-processing conditions, etc. are controlled and adjusted can

When the phase shift layer 20 is formed using sputtering equipment, a magnet is placed on the sputtering equipment and a magnetic field is formed so that plasma is distributed over the entire surface of the target in the chamber. In addition, the distribution and strength of the magnetic field may affect the density of the film formed by the sputtering equipment.

Specifically, as the strength of the magnetic field increases, the density of the plasma formed in the chamber increases, and thus the formed phase shift layer 20 may become denser. As the intensity of the magnetic field decreases, the density of the plasma formed in the chamber decreases, so that the phase shift layer 20 formed can be eliminated.

The phase shift layer 10 of the photomask 200 is formed by patterning after the light blocking layer 30 positioned on the phase shift layer 10 is removed. If the photomask 20 further includes another film between the phase shift layer 20 and the light blocking layer 30, the other film is also removed. That is, the blank mask 200 is processed so that the outermost surface of the phase shift layer 20 is exposed, and the photomask is formed. As a method of removing the light blocking layer 30 and the other film, an etching method using an etchant may be used, but is not limited thereto.

blank mask

As shown in FIG. 3 , the blank mask 100 includes a transparent substrate 10, a phase shift layer 20 disposed on the transparent substrate 10, and a light blocking layer disposed on the phase shift layer 20. Layer 30 is included.

The material of the transparent substrate 10 is not limited as long as it has light transmittance for exposure light and can be applied to a photomask. Specifically, transmittance of the transparent substrate 10 to exposure light having a wavelength of 200 nm or less may be 85% or more. The transmittance may be 87% or more. Illustratively, a synthetic quartz substrate may be applied to the transparent substrate 10 . In this case, the transparent substrate 10 can suppress attenuated light passing through the transparent substrate 10 .

In addition, optical distortion may be reduced by adjusting surface characteristics of the transparent substrate 10 such as flatness and roughness.

phase inversion layer

The phase shift layer 20 may be positioned on the front side of the transparent substrate 10 .

The phase shift layer 20 may include a phase difference adjustment layer 21 positioned on the upper surface of the transparent substrate and a protective layer 22 positioned on the phase difference adjustment layer 21 .

The phase inversion layer 20 , the retardation adjustment layer 21 , and the protective layer 22 may each include a transition metal, silicon, oxygen, and nitrogen.

The retardation adjustment layer 21 is a layer in which transition metal, silicon, oxygen, and nitrogen are evenly included within a range of 5 atomic % in the depth direction in the phase inversion layer 20 . The phase difference adjustment layer 21 can substantially adjust the phase difference and transmittance of the exposure light passing through the phase shift layer 20 .

Specifically, the retardation adjusting layer 21 has a characteristic of shifting the phase of exposure light incident from the back side of the transparent substrate 10 . Due to this characteristic, the phase shift layer 20 effectively cancels diffracted light generated at the edge of the transmission portion of the photomask, thereby improving the resolution of the photomask during a lithography process.

In addition, the phase difference adjustment layer 21 attenuates exposure light incident on the surface of the phase shift layer 20 . Through this, the phase shift layer 20 can properly block the exposure light while offsetting the diffraction light.

The protective layer 22 is formed on the surface of the phase inversion layer and has a distribution in which the oxygen content continuously decreases and the nitrogen content continuously increases in the depth direction from the surface. The protective layer 22 may improve durability of the phase shift layer by suppressing damage to the phase shift layer pattern or unnecessary etching during the etching process and cleaning process of the photomask. In addition, the protective layer 22 can partially suppress the variation in optical characteristics caused by oxidation of the retardation adjusting layer 21 due to exposure light during an exposure process.

In the blank mask 100, the light blocking layer 30 is disposed on the phase shift layer. The light blocking layer 30 may be used as an etching mask for the phase shift layer 20 when the phase shift layer 20 is etched in a pattern shape. In addition, the light blocking layer 30 may block transmission of exposure light incident from the rear side of the transparent substrate 10 .

The light blocking layer may have a single layer structure. The light blocking layer may have a multilayer structure of two or more layers. The light blocking layer may be formed through sputtering. The light blocking layer may have a multilayer structure of two or more layers depending on sputtering control conditions.

The phase inversion layer 20 may include a transition metal, silicon, oxygen, and nitrogen. The transition metal may be one or more elements selected from molybdenum (Mo), tantalum (Ta), zirconium (Zr), and the like, but is not limited thereto. Illustratively, the transition metal may be molybdenum.

The phase shift layer 20 may include 1 to 10 atomic % of a transition metal. The phase shift layer 20 may include 2 to 7 atomic % of a transition metal. The phase inversion layer 20 may include 15 to 60 atomic % of silicon. The phase inversion layer 20 may include 25 to 50 atomic % of silicon. The phase inversion layer 20 may contain 30 to 60 atomic % of nitrogen. The phase inversion layer 20 may include 35 to 55 atomic % of nitrogen. The phase inversion layer 20 may contain 5 to 35 atomic % of oxygen. The phase inversion layer 20 may contain 10 to 25 atomic % of oxygen. In this case, the phase shift layer 20 may have optical characteristics suitable for a lithography process using short-wavelength exposure light, specifically, light having a wavelength of 200 nm or less.

The phase inversion layer 20 may additionally include other elements in addition to the above-mentioned elements. Illustratively, the phase inversion layer 20 may include argon (Ar) or helium (He).

The phase shift layer 20 may have different contents for each element in the thickness direction.

The content distribution of each element formed in the depth direction of the retardation adjustment layer 21 and the protective layer 22 can be confirmed by measuring a depth profile of the phase shift layer. Illustratively, the depth profile may be measured using Thermo Scientific's K-alpha model.

The retardation adjustment layer 21 and the passivation layer 22 may have different content for each element such as a transition metal, silicon, oxygen, and nitrogen.

The retardation adjustment layer 21 may include 3 to 10 atomic % of a transition metal. The retardation adjustment layer 21 may include 4 to 8 atomic % of a transition metal. The retardation adjustment layer 21 may include 20 to 50 atomic % of silicon. The retardation adjustment layer 21 may contain 30 to 40 atomic % of silicon. The phase difference adjustment layer 21 may contain 2 to 10 atomic % of oxygen. The phase difference adjustment layer 21 may contain 3 to 8 atomic % of oxygen. The retardation adjustment layer 21 may contain 40 to 60 atomic % of nitrogen. The retardation adjustment layer 21 may contain 45 to 55 atomic % of nitrogen. In this case, a blank mask having excellent pattern resolution can be provided when short-wavelength exposure light, specifically, light having a wavelength of 200 nm or less is applied as exposure light during manufacture of the photomask.

As the protective layer 22 contains more oxygen, it can stably protect the retardation adjustment layer 21 from exposure light and cleaning solution, but the degree of optical characteristic variation of the entire phase shift layer 20 may increase. Therefore, by controlling the content distribution of oxygen and nitrogen in the protective layer 22, the phase shift layer 20 can have desired optical properties while having sufficient light resistance and chemical resistance.

The protective layer 22 may contain 20 to 40 atomic % of nitrogen. The protective layer 22 may contain 25 to 35 atomic % of nitrogen. The protective layer 22 may contain 10 to 50 atomic % of oxygen. The protective layer 22 may contain 20 to 40 atomic % of oxygen. The protective layer 22 may include 10 to 50 atomic % of silicon. The protective layer 22 may include 20 to 40 atomic % of silicon. The protective layer 22 may include 0.5 to 5 atomic % of a transition metal. The protective layer 22 may include 1 to 3 atomic % of a transition metal. In this case, the protective layer 22 can sufficiently suppress deterioration of the retardation adjusting layer 21 .

The protective layer 22 may include a region in which the nitrogen content (atomic %) compared to the oxygen content (atomic %) in the thickness direction is 1 or more, and the region has a thickness of 40 to 60% of the total thickness of the protective layer 22. can have The region may have a thickness of 45 to 55% of the total thickness of the protective layer 22 . In this case, fluctuations in optical characteristics of the phase shift layer 20 due to formation of the protective layer 22 can be effectively suppressed.

The protective layer 22 may include a region in which the ratio of the nitrogen content (atomic %) to the oxygen content (atomic %) in the thickness direction is 0.4 to 2, and the region is the entire thickness of the protective layer 22 (100%). It may have a thickness of 30 to 80% compared to. The region may have a thickness of 40 to 60% of the total thickness (100%) of the protective layer 22 . In this case, it is possible to provide a blank mask capable of manufacturing a photomask having sufficient long-term durability and excellent resolution.

The content of each element of the phase shift layer 20, the phase difference adjustment layer 21, and the protective layer 22 and the distribution of the content of each element formed in the thickness direction can be confirmed by measuring a depth profile. Illustratively, it can be measured through Thermo Scientific's K-alpha model.

The measurement of the thickness of a region in which the ratio of the nitrogen content (atomic %) to the oxygen content (atomic %) in the thickness direction is 1 or more can be confirmed by measuring a depth profile. However, it is assumed that the etching rate for each depth of the protective layer 22 is constant in the depth profile.

Measurement of the thickness of a region in which the ratio of nitrogen content (atomic %) to oxygen content (atomic %) in the thickness direction is 0.4 to 2 can be confirmed by measuring a depth profile. However, it is assumed that the etching rate for each depth of the protective layer 22 is constant in the depth profile.

The phase shift layer 20 may have a phase difference of 160° to 200° for light having a wavelength of 200 nm or less. The phase shift layer 20 may have a phase difference of 160° to 200° with respect to ArF light. The phase shift layer 20 may have a phase difference of 170° to 190° for light having a wavelength of 200 nm or less. The phase shift layer 20 may have a phase difference of 170° to 190° with respect to ArF light. The phase shift layer 20 may have transmittance of 3 to 10% for light having a wavelength of 200 nm or less. The phase shift layer 20 may have transmittance of 3 to 10% for ArF light. The phase shift layer 20 may have transmittance of 4 to 8% for light having a wavelength of 200 nm or less. The phase shift layer 20 may have transmittance of 4 to 8% for ArF light. In this case, the photomask including the phase shift layer 20 may expose more sophisticated fine patterns on the wafer in an exposure process to which short-wavelength exposure light is applied.

For example, the phase difference and transmittance of the phase shift layer 20 may be measured through Lasertec's MPM193 model.

The refractive index of the protective layer 22 for light having a wavelength of 200 nm or less may be 1.3 to 2. The protective layer 22 may have a refractive index of 1.3 to 2 for ArF light. The refractive index of the protective layer 22 for light having a wavelength of 200 nm or less may be 1.4 to 1.8. The refractive index of the protective layer 22 for ArF light may be 1.4 to 1.8. An extinction coefficient of the protective layer 22 for light having a wavelength of 200 nm or less may be 0.2 to 0.4. An extinction coefficient of the protective layer 22 for ArF light may be 0.2 to 0.4. An extinction coefficient of the protective layer 22 for light having a wavelength of 200 nm or less may be 0.25 to 0.35. An extinction coefficient of the protective layer 22 for ArF light may be 0.25 to 0.35. In this case, the optical characteristic variation effect of the phase shift layer 20 due to the formation of the protective layer 22 can be minimized.

The retardation adjustment layer 21 may have a refractive index of 2 to 4 for light having a wavelength of 200 nm or less. The phase difference adjusting layer 21 may have a refractive index of 2 to 4 for ArF light. The refractive index of the retardation adjustment layer 21 for light having a wavelength of 200 nm or less may be 2.5 to 3.5. The refractive index of the retardation adjustment layer 21 for ArF light may be 2.5 to 3.5. An extinction coefficient of the retardation adjustment layer 21 for light having a wavelength of 200 nm or less may be 0.3 to 0.7. An extinction coefficient of the retardation adjustment layer 21 for ArF light may be 0.3 to 0.7. An extinction coefficient of the retardation adjustment layer 21 for light having a wavelength of 200 nm or less may be 0.4 to 0.6. An extinction coefficient of the phase difference adjustment layer 21 for ArF light may be 0.4 to 0.6. In this case, the photomask including the phase shift layer 20 may exhibit excellent patterning effect during an exposure process on the wafer surface.

Illustratively, the refractive index and extinction coefficient of the phase shift layer 20, the protective layer 22 and the phase difference adjustment layer 21 included in the phase shift layer 20 can be measured through NANO-VIEW's MG-PRO equipment. can

A thickness ratio of the protective layer 22 to the thickness 1 of the phase shift layer 20 may be 0.04 to 0.09. The thickness ratio may be 0.05 to 0.08. In this case, the protective layer 22 can stably protect the retardation adjustment layer 21 .

The protective layer 22 may have a thickness of 25 Å or more and 80 Å or less. The protective layer 22 may have a thickness of 35 Å or more and 45 Å or less. In this case, it is possible to provide the phase shift layer 20 that exhibits stable optical properties despite a plurality of exposure processes and cleaning processes while efficiently controlling the degree of change in optical properties affecting the entire phase shift layer.

Illustratively, the phase shift layer 20 and the thickness of each layer constituting the phase shift layer 20 can be confirmed through a TEM (Transmission Electron Microscopy) image of a cross section of the phase shift layer 20 .

Crystal Characteristics of Phase Inversion Layer: Amorphous Index

Crystal characteristics of the phase shift layer may be similar to those of the transparent substrate.

When analyzed by X-ray diffraction (XRD) analysis, the phase inversion layer and the transparent substrate may have crystal characteristics similar to each other.

Referring to FIG. 5 , the XRD analysis may be performed in a normal mode. The normal mode XRD analysis is a θ-2θ mode. In the normal mode XRD analysis, X-rays are generated from the X-ray generator 60 and emitted to the sample 30, and X-rays reflected from the sample are detected through the detector 70.

At this time, the X-ray generator 60 emits X-rays to the sample 30 at a predetermined incident angle θ. The incident angle θ is an angle between the direction of X-rays from the X-ray generator and the horizontal surface of the sample. In addition, the X-ray generator emits X-rays to the sample while changing the incident angle θ.

The detector 70 is disposed opposite to the position where the X-ray generator is disposed based on the position where the X-ray is incident on the sample. In addition, the detector detects X-rays having a predetermined emission angle (θ) among X-rays reflected from the sample. The emission angle is an angle between a direction of an X-ray reflected from the sample and a horizontal surface of the sample.

In addition, the detector 70 is scanned corresponding to the scanning direction of the X-ray generator. That is, the detector is scanned so that the incident angle θ and the emission angle θ are equal to each other when the X-ray generator is scanned. In the normal mode XRD analysis, the X-ray generator and the detector may move on the same plane so that the incident angle and the emission angle are equal to each other. In addition, the X-ray generator may be moved such that a distance from a position where the X-ray is incident on the sample is constant. In addition, the detector may be moved such that a distance from a position where the X-rays are reflected in the sample is constant. That is, the X-ray generator and the detector may be moved while drawing an arc.

In the normal mode XRD analysis, an X-ray source may be a Cu target. In addition, in the normal mode XRD analysis, the wavelength of the X-ray may be about 1.542 nm. Also, in the normal mode XRD analysis, a voltage used to generate the X-rays may be about 45 kV. Also, in the normal mode XRD analysis, a current used to generate the X-rays may be about 200 mA. In addition, in the normal mode XRD analysis, the measurement range of 2θ may be about 10° to about 100°. In addition, the normal mode XRD analysis may be performed at every change of about 0.05 ° based on 2θ. Also, in the normal mode XRD analysis, the scan speed of the X-ray generator and the detector may be about 5°/min.

More specifically, in the normal mode XRD analysis, the X-ray source is a copper target, the wavelength of the X-ray is about 1.542 nm, and the voltage used to generate the X-ray is about 45 kV, the current used to generate the X-rays is about 200 mA, the measurement range of 2θ is about 10 ° to about 100 °, and the measurement is performed every time the 2θ changes by about 0.05 °, the X-ray generator and a scan speed of the detector may be about 5°/min.

In the photomask and/or the blank mask, the phase shift layer and the transparent substrate may have crystal characteristics similar to each other. Crystal characteristics of the phase shift layer measured by the normal mode XRD analysis and crystal characteristics of the transparent substrate measured by the normal mode XRD analysis may be similar to each other.

When normal mode XRD analysis is performed on the phase inversion layer, the X-ray intensity measured after reflection has a maximum value between 15° and 30° in 2θ, and the normal mode XRD analysis is performed on the rear surface (lower surface) of the transparent substrate. When proceeding, the X-ray intensity measured after reflection may have a maximum value between 15° and 30° of 2θ.

Hereinafter, the XRD analysis in the phase shift layer means that the XRD analysis of the photomask or the blank mask is performed on the phase shift layer, and the XRD analysis is performed in the direction of the phase shift layer. Similarly, that the XRD analysis is conducted on the transparent substrate means that the XRD analysis is conducted on the back side of the transparent substrate, and it is also expressed that the XRD analysis is conducted in the direction of the transparent substrate.

When the normal mode XRD analysis is performed on the phase shift layer, the measured X-ray intensity after reflection has a maximum value between 20° and 25° for 2θ, and when the normal mode XRD analysis is performed on the transparent substrate, after reflection The measured X-ray intensity may have a maximum value between 20° and 25° of 2θ.

In addition, when the normal mode XRD analysis is performed on the phase shift layer, 2θ is the maximum X-ray intensity measured after reflection and when the normal mode XRD analysis is performed on the transparent substrate, the X-ray intensity measured after reflection is maximum. The difference in 2θ may be within 5°. More specifically, when the normal mode XRD analysis is performed on the phase inversion layer, 2θ is the maximum X-ray intensity measured after reflection, and when the normal mode XRD analysis is performed on the transparent substrate, the X-ray intensity measured after reflection is the maximum. The difference in 2θ may be within 3°. When the normal mode XRD analysis is performed on the phase shift layer, 2θ is the maximum X-ray intensity measured after reflection and 2θ is the maximum X-ray intensity measured after reflection when the normal mode XRD analysis is performed on the transparent substrate. The difference can be less than 1°.

In addition, in the photomask and/or the blank mask, a first amorphous index AI1 represented by Equation 1 below may be 0.9 to 1.1.

[Equation 1]

Here, XM1 is the maximum value of the X-ray intensity measured when the normal mode XRD analysis is performed on the phase shift layer, and XQ1 is the measured X-ray intensity when the normal mode XRD analysis is performed on the lower surface of the transparent substrate. is the maximum value of the line intensity.

The first amorphous index may be 0.95 to 1.05. The first amorphous index may be 0.97 to 1.03. The first amorphous index may be 0.98 to 1.02. The first amorphous index may be 0.99 to 1.01.

Also, in the photomask and/or the blank mask, a third amorphous index (AI3) represented by Equation 3 below may be 0.9 to 1.1.

[Equation 3]

Here, AM1 is the area when 2θ is between 15° and 30° in the X-ray intensity measured after reflection when XRD analysis is performed on the phase reversal layer, and AQ1 is the area where XRD analysis is performed on the transparent substrate. As it progresses, it is the area when 2θ is between 15° and 30° in the X-ray intensity measured after reflection.

The third amorphous index may be 0.95 to 1.05. The third amorphous index may be 0.97 to 1.03. The third amorphous index may be 0.98 to 1.02. The third amorphous index may be 0.99 to 1.01.

Also, in the photomask and/or the blank mask, a fourth amorphous index (AI4) represented by Equation 4 below may be 0.9 to 1.1.

[Equation 4]

Here, XM4 is the reflected X-ray intensity when 2θ is 43° when the XRD analysis is performed on the phase shift layer, and XQ4 is the reflected X-ray intensity when 2θ is 43° when the XRD analysis is performed on the lower surface of the transparent substrate. is the reflected X-ray intensity when .

The fourth amorphous index may be 0.95 to 1.05. The fourth amorphous index may be 0.97 to 1.03. The fourth amorphous index may be 0.98 to 1.02. The fourth amorphous index may be 0.99 to 1.01.

Referring to FIG. 6 , the XRD analysis may be performed as a fixed mode XRD analysis. In the fixed mode XRD analysis, X-rays are generated from an X-ray generator and emitted to a sample, and X-rays reflected from the sample are detected through a detector.

At this time, in the fixed mode XRD analysis, the X-ray generator emits X-rays to the sample at a fixed incident angle (eg, 1°). The angle of incidence is an angle between a direction of X-rays from the X-ray generator and a horizontal surface of the sample.

The detector is disposed opposite to the position where the X-ray generator is disposed based on the position where the X-ray is incident on the sample. In addition, the detector detects X-rays having a predetermined emission angle (θ) among X-rays reflected from the sample. The emission angle is an angle between a direction of an X-ray reflected from the sample and a horizontal surface of the sample.

In addition, the detector includes the X-ray generator and a position where the X-rays are incident, and is scanned in a plane perpendicular to the horizontal plane of the sample. That is, the detector is scanned to detect X-rays emitted at various emission angles θ. In the fixed mode XRD analysis, the X-ray generator, the detector, and the area to be measured in the sample are disposed on the same plane. Also, the detector may move on the same plane. In addition, the detector may be moved such that a distance from a position where the X-rays are reflected in the sample is constant. That is, the detector may be moved while drawing an arc.

In the fixed mode XRD analysis, the incident angle may be about 1°. In the fixed mode XRD analysis, an X-ray source may be a Cu target. In addition, in the fixed mode XRD analysis, the wavelength of the X-ray may be about 1.542 nm. Also, in the fixed mode XRD analysis, a voltage used to generate the X-rays may be about 45 kV. Also, in the fixed mode XRD analysis, a current used to generate the X-rays may be about 200 mA. In addition, in the fixed mode XRD analysis, the range of 2θ of the detector may be about 10° to about 100°. In addition, the fixed mode XRD analysis may be performed at every change of about 0.05 ° based on 2θ. In addition, in the fixed mode XRD analysis, the scan speed of the detector may be about 5°/min.

More specifically, in the fixed mode XRD analysis, the incident angle is about 1°, the X-ray source is a copper target, the wavelength of the X-ray is about 1.542 nm, and the X-ray source is a Cu target. The voltage used to generate the X-rays is about 45 kV, the current used to generate the X-rays is about 200 mA, the measurement range of 2θ is about 10° to about 100°, and every time the 2θ changes by about 0.05°. The measurement is performed, and the scan rate of the detector may be about 5°/min.

In the photomask and/or the blank mask, the phase shift layer and the transparent substrate may have crystal characteristics similar to each other. Crystal characteristics of the phase shift layer measured by the fixed mode XRD analysis and crystal characteristics of the transparent substrate measured by the fixed mode XRD analysis may be similar to each other.

When the fixed mode XRD analysis is performed on the phase shift layer, the X-ray intensity measured after reflection has a first peak between 15° and 25° in 2θ, and when the fixed mode XRD analysis is performed on the transparent substrate, the reflection The measured X-ray intensity may have a second peak between 15° and 25° in 2θ.

2θ of the first peak may be between about 17° and about 23°, and 2θ of the second peak may be between about 17° and about 23°.

2θ of the first peak may be between about 19° and about 22°, and 2θ of the second peak may be between about 19° and about 22°.

A difference between 2θ at the first peak and 2θ at the second peak may be within about 5°. A difference between 2θ at the first peak and 2θ at the second peak may be within about 3°. A difference between 2θ at the first peak and 2θ at the second peak may be within about 2°.

In the photomask and/or the blank mask, a second amorphous index (AI2) represented by Equation 2 below may be from about 0.9 to about 1.1.

[Equation 2]

Here, XM2 is the maximum value of the first peak, and XQ2 is the maximum value of the second peak.

The second amorphous index may be about 0.95 to about 1.05. The second amorphous index may be about 0.97 to about 1.03. The second amorphous index may be from about 0.98 to about 1.02.

Manufacturing method of phase inversion layer

Among the phase shift layer 20 of the embodiment, the phase difference control layer 21 may be manufactured by forming a thin film on the transparent substrate 10 through sputtering.

The sputtering process may use a DC power source or an RF power source.

A target and a sputtering gas may be selected in consideration of the composition of a material constituting the thin film.

In the case of a sputtering target, one target containing both a transition metal and silicon may be applied, and a target containing a transition metal and a target containing silicon may be respectively applied. When one target is applied as a sputtering target, the transition metal content compared to the sum of transition metal and silicon content of the target may be 30% or less. The transition metal content of the target relative to the sum of the transition metal and silicon content may be 20% or less. The transition metal content of the target relative to the sum of the transition metal and silicon content may be 10% or less. The content of the transition metal relative to the sum of the transition metal and silicon contents of the target may be 2% or more. In this case, the phase shift layer formed during sputtering using the target may have desired optical characteristics.

In the case of the sputter gas, the sputter gas may be prepared in consideration of a composition other than the composition contained in the target among elements constituting the thin film. Specifically, CH ₄ as a gas containing carbon, O ₂ as a gas containing oxygen, N ₂ as a gas containing nitrogen, etc. may be introduced, but is not limited thereto. An inert gas may be added to the sputtering gas in addition to a gas containing an element constituting the thin film. Examples of the inert gas include Ar and He, but are not limited thereto. Depending on the composition of the inert gas, the film quality of the thin film formed during sputtering may vary. Therefore, the optical properties of the thin film can be controlled by adjusting the composition of the inert gas. The sputtering gas may be introduced into the chamber for each gas having the same composition. The sputtering gas may be introduced into the chamber by mixing the gases of each composition.

A magnet may be disposed in the chamber to improve the uniformity of the thickness and in-plane optical characteristics of the thin film to be formed. Specifically, by placing the magnet on the back side of the sputtering target and rotating the magnet at a constant speed, a constant distribution of plasma can be maintained on the entire surface of the target. The magnet may rotate at a speed of 50 to 200 rpm.

The rotational speed of the magnet may be fixed at a constant speed during sputtering. The rotational speed of the magnet can be varied during sputtering. The rotation speed of the magnet can be increased from the initial rotation speed to a constant speed during sputtering.

The rotation speed of the magnet may be increased by 5 to 20 rpm per minute from the initial rotation speed during sputtering. The rotation speed of the magnet may be increased by 7 to 15 rpm per minute from the initial rotation speed during sputtering. In this case, the desired film properties in the thickness direction of the phase inversion layer can be easily controlled.

As described above, adjusting the magnetic field of the magnet controls the density of the plasma formed in the chamber, thereby controlling the crystal characteristics of the phase shift layer 20 to be deposited. The magnetic field of the magnet applied during sputtering may be 25 to 60 mT. The magnetic field may be 30 to 50 mT. In this case, the phase shift layer 20 to be formed may have crystal characteristics similar to those of the transparent substrate in a lithography process to which short-wavelength exposure light is applied.

In the sputtering process, the T/S distance, which is the distance between the target and the substrate, and the angle between the substrate and the target may be adjusted. The T/S distance may be 240 to 260 mm. In this case, the film formation speed can be stably controlled, and the uniformity of in-plane optical properties of the thin film to be formed can be improved. The angle between the substrate and the target may be 20 to 30 degrees. In this case, excessive increase in the internal stress of the thin film to be formed can be suppressed.

In the sputtering process, the rotational speed of the substrate to be deposited may be adjusted. The rotational speed of the substrate to be filmed may be 2 to 20 RPM. The rotation speed of the substrate may be 5 to 15 RPM. When the rotational speed of the substrate to be formed is adjusted within this range, the formed phase shift layer 20 can have stable durability while improving the degree of equalization of optical characteristics in the in-plane direction.

In addition, when the phase difference control layer 21 is formed, the intensity of the voltage applied to the sputtering target may be adjusted. A discharge region including a plasma atmosphere in the chamber is formed by supplying a voltage to a target located in the sputtering chamber. By adjusting the strength of the voltage, the plasma atmosphere in the chamber can be adjusted together with the magnet to control the film quality of the film formed during sputtering. The strength of the voltage applied to the sputtering target may be 1 to 3 kW. The intensity of the voltage may be 1.5 to 2.5 kW. The intensity of the voltage may be 1.8 to 2.2 kW. In this case, the thermal fluctuation of the phase shift layer 20 in the thickness direction according to temperature may be controlled within a certain range.

A spectroscopic ellipse analyzer can be installed in the sputtering equipment. Through this, the deposition time can be controlled so that the retardation control layer 21 to be formed has desired optical characteristics. Specifically, after setting the angle (θ) formed by the incident light (L _i ) with the surface of the retardation control layer 21 to be formed, the Del value of the retardation control layer 21 to be formed can be monitored in real time during the deposition process. there is. The phase shift layer 20 may have desired optical characteristics by performing a deposition process until the Del value falls within a set range.

Optical characteristics of each layer of the thin film to be measured can be measured by measuring the phase difference between the P wave and S wave of the reflected light while changing the photon energy of the incident light of the spectroscopic ellipse analyzer. Specifically, when the photon energy of the incident light is relatively low, the incident light forms a long wavelength, and thus the optical characteristics of the lower layer of the thin film to be measured can be measured. When the photon energy of the incident light is relatively high, the incident light forms a short wavelength, and thus the optical characteristics of the upper layer of the thin film to be measured can be measured.

For example, the phase inversion layer has a photon energy of 1.8 to 2.15 eV at a point where a Del_1 value according to Equation A below is 0, measured by a spectroscopic ellipse analyzer by applying an incident angle of 64.5°.

[Equation A]

In Equation A, the DPSp value is the phase difference between the P wave and the S wave when the phase shift layer is measured with a spectroscopic ellipse analyzer by applying an incident angle of 64.5 ° and the phase difference between the P wave and the S wave of the reflected light is 180 ° or less. , If the phase difference between the P wave and the S wave of the reflected light exceeds 180°, it is a value obtained by subtracting the phase difference between the P wave and the S wave from 360°.

The PE value is a photon energy within the range of 1.5 to 3.0 eV, when PE ₁ is 1.5 eV and PE ₂ is 3 eV.

UV light source irradiation may be performed on the surface of the retardation control layer 21 immediately after the sputtering process is finished. In the sputtering process, Si of the SiO ₂ matrix constituting the transparent substrate 10 may be substituted with a transition metal, and O may be substituted with N. If the sputtering process is continued, the transition metal is out of the solubility limit, and is placed in an interstitial site rather than being substituted with Si in the SiO ₂ matrix, so that the transition metal is an element such as Si, O, N, etc. can form a mixture with The mixture may be in a homogeneous state or inhomogeneous state.

In the case of the retardation control layer 21 on which a non-uniform mixture is formed on the surface, haze defects may be formed on the surface of the retardation control layer 21 due to short-wavelength exposure light during an exposure process. In addition, when sulfuric acid is used as a cleaning solution in a cleaning process for removing defects, sulfur ions may remain on the surface of the retardation control layer 21 after the cleaning process. Residual sulfur ions may react with the non-uniform mixture to generate growth defects on the surface of the retardation control layer 21 when exposed to strong energy from exposure light for a long period of time during the wafer exposure process. Therefore, the surface of the retardation control layer 21 is exposed to UV light of a predetermined wavelength to uniformize the content of transition metal and N in the mixture on the surface of the retardation control layer 21 in the film direction, thereby improving the light resistance and resistance of the retardation control layer 21. Chemical properties can be improved.

The surface treatment of the phase difference control layer 21 using UV light may be performed by exposing the phase difference control layer 21 to a light source having a wavelength of 200 nm or less at a power of 2 to 10 mW/cm ² for 5 to 20 minutes.

Together with or separately from the UV light irradiation process, the retardation control layer 21 may be heat treated. The UV light irradiation process and heat treatment may be applied using heat generated by UV irradiation, or may be performed as separate processes.

The retardation control layer 21 formed through the sputtering process may have internal stress. Internal stress may be compressive stress or tensile stress depending on sputtering conditions. The internal stress of the retardation control layer 21 may cause the substrate to warp, which may cause a decrease in resolution of the photomask manufactured using the blank mask 100 . When heat treatment is applied to the retardation control layer 21 , internal stress of the phase shift layer 20 may be reduced, thereby reducing warpage of the substrate.

The protective layer 22 may be formed on the retardation adjustment layer 21 through a separate sputtering process. The protective layer 22 may be formed by performing a surface treatment process on the retardation adjusting layer 21 after forming the retardation adjusting layer 21 .

The protective layer 22 may be formed through a heat treatment process after forming the retardation adjustment layer 21 through sputtering. During the heat treatment process, the protective layer 22 may be formed by reacting the surface of the retardation adjustment layer 21 with atmospheric gas. However, the manufacturing method of the protective layer 22 is not limited thereto.

During the heat treatment process, the protective layer 22 may be formed on the surface of the retardation control layer 21 by introducing atmospheric gas into the chamber. Atmospheric gas may be introduced during the heat treatment process. Atmospheric gases include He, Ar, and the like, but are not limited thereto.

The heat treatment process may include a temperature raising step, a temperature maintaining step, a temperature lowering step, and a protective layer forming step. The heat treatment process may be performed by disposing a blank mask having a retardation control layer 21 formed thereon in a chamber and then heating it using a lamp.

The temperature raising step is a step of raising the temperature in the chamber from room temperature to a set temperature of 150 to 500°C. The temperature maintaining step is a step of maintaining the temperature in the chamber at the set temperature and maintaining the pressure in the chamber at 0.1 to 2.0 Pa. The temperature maintaining step may be performed for 5 to 60 minutes. The temperature lowering step is a step of lowering the temperature in the chamber from a set temperature to room temperature. The protective layer forming step is a step of forming a protective layer on the surface of the phase inversion layer by introducing a gas containing a reactive gas into the chamber after completing the temperature lowering step. The reactive gas may include O ₂ . In the protective layer forming step, the gas introduced into the chamber may include at least one of N ₂ , Ar, and He. Specifically, in the protective layer forming step, O ₂ gas may be introduced into the chamber at 0.3 to 2.5 SLM (Standard Liter per Minute). The O ₂ gas may be introduced into the chamber at 0.5 to 2 SLM. The protective layer forming step may proceed for 10 minutes to 60 minutes. The protective layer forming step may proceed for 12 minutes to 45 minutes. In this case, the content of each element in the thickness direction of the passivation layer 22 is adjusted so that variations in optical characteristics of the phase shift layer 20 due to the passivation layer 22 can be suppressed.

The distribution of Del_2 values when PE ₁ was 1.5 eV and PE ₂ was 5.0 eV was measured using a spectroscopic ellipse analyzer (manufactured by Nano-View Co., Ltd. MG-PRO). Specifically, after setting the angle of the incident light to 64.5 for the surface of the phase shift film on which the film formation for each example and comparative example was completed, the phase difference between the P wave and the S wave according to the photon energy was measured and converted into a Del_2 value.

When the value of PE ₁ is 3.0 eV and the value of PE ₂ is 5.0 eV, the blank mask 100 may have a photon energy of 3.9 to 4.7 eV at a point where Del_2 represented by Equation B below is 0.

[Equation B]

In Equation B, the DPS value is the P wave when the phase difference between the P wave and the S wave of the reflected light is 180° or less when the surface of the phase shift film is measured with a spectroscopic ellipse analyzer by applying an incident angle of 64.5° on the protective layer. and the phase difference between the S waves, and if the phase difference between the P wave and the S wave of the reflected light exceeds 180°, it is a value obtained by subtracting the phase difference between the P wave and the S wave from 360°.

The PE value is a photon energy within the range of PE ₁ to PE ₂ .

light blocking layer

The light blocking layer 30 may have a single layer structure. The light blocking layer 30 may have a multilayer structure of two or more layers. The light blocking layer 30 may be formed through sputtering. The light blocking layer 30 may have a two or more layer structure depending on sputtering control conditions. During the sputtering process of the light blocking layer 30 , multiple layers of the light blocking layer 30 may be formed by changing the flow rate of each atmosphere gas for each layer. During the light blocking layer 30 sputtering process, a plurality of light blocking layers 30 may be formed by changing a sputtering target for each layer.

The light blocking layer 30 may include chromium and nitrogen. The light blocking layer 30 may include chromium, oxygen, nitrogen, and carbon. The content of each element compared to the entire light blocking layer 30 may be different in the thickness direction. The content of each element compared to the entire light blocking layer 30 may be different for each layer in the case of a plurality of light blocking layers 30 .

The light blocking layer 30 may include 44 to 60 atomic % of chromium. The light blocking layer 30 may include 47 to 57 atomic % of chromium. The light blocking layer 30 may include 5 to 30 atomic % of carbon. The light blocking layer 30 may include 7 to 25 atomic % of carbon. The light blocking layer 30 may contain 3 to 20 atomic % of nitrogen. The light blocking layer 30 may contain 5 to 15 atomic % of nitrogen. The light blocking layer 30 may contain 20 to 45 atomic % of oxygen. The light blocking layer 30 may contain 25 to 40 atomic % of oxygen. In this case, the thickness of the light blocking layer 30 may be adjusted so as to have sufficient quenching properties, and may be induced to have appropriate etching properties.

The phase shift layer and the light blocking layer may be combined and expressed as a multilayer. That is, the multilayer (not shown) includes the phase shift layer 20 and the light blocking layer 30 . The multilayer may form a blind pattern on the transparent substrate 10 to suppress transmission of exposure light.

The optical density for light having a wavelength of 200 nm or less of the multilayer may be 3 or more. The optical density of ArF light of the multilayer may be 3 or more. The optical density for light having a wavelength of 200 nm or less of the multilayer may be 3.5 or more. The optical density of ArF light of the multilayer may be 3.5 or more. In this case, the multilayer may have excellent light blocking properties.

Crystal Characteristics of Light-Shielding Layer: Amorphous Index

The light blocking layer has crystal characteristics different from those of the transparent substrate. Crystal characteristics of the light blocking layer and crystal characteristics of the transparent substrate may be different from each other. The XRD analysis result of the light blocking layer and the XRD analysis result of the transparent substrate may be different from each other. A normal mode XRD analysis result of the light blocking layer and a normal mode XRD analysis result of the transparent substrate may be different from each other. A fixed mode XRD analysis result of the light blocking layer and a fixed mode XRD analysis result of the transparent substrate may be different from each other.

When the normal mode XRD analysis is performed through the light blocking layer, the X-ray intensity measured after reflection has a maximum value between 15° and 30° in 2θ, and through the lower surface of the transparent substrate, the normal mode XRD analysis When this proceeds, the X-ray intensity measured after reflection may have a maximum value between 15° and 30° of 2θ.

In this case, in the photo mask and the blank mask, a fifth amorphous index (AI5) represented by Equation 5 below may be 0.5 to 0.97.

[Equation 5]

Here, XC1 is the maximum value of the X-ray intensity measured by the normal mode XRD analysis through the light-shielding layer, and XQ1 is the maximum value of the X-ray intensity measured by the normal mode XRD analysis through the lower surface of the transparent substrate. is the maximum

The fifth amorphous index may be 0.7 to 0.97. The fifth amorphous index may be 0.5 to 0.95. The fifth amorphous index may be 0.7 to 0.95. The fifth amorphous index may be 0.7 to 0.93. The fifth amorphous index may be 0.9 to 0.93.

In the photomask and the blank mask, a sixth amorphous index AI6 represented by Equation 6 below may be 1.05 to 1.4.

[Equation 6]

Here, XM4 is the X-ray intensity measured when the normal mode XRD analysis is performed on the light-blocking layer and 2θ is 43°, and XQ4 is the normal mode XRD analysis performed on the lower surface of the transparent substrate. When 2θ is 43°, it is the measured X-ray intensity.

The sixth amorphous index may be 1.06 to 1.4. The sixth amorphous index may be 1.07 to 1.4. The sixth amorphous index may be 1.08 to 1.4.

The light blocking layer of the embodiment may be formed in contact with the phase shift layer, and may be formed in contact with another thin film positioned on the phase shift layer.

The light blocking layer may include a lower layer and an upper layer positioned on the lower layer.

The sputtering process may use a DC power source or an RF power source.

In consideration of the composition of the light-blocking layer, a target and a sputtering gas may be selected during sputtering of the light-blocking layer. When the light blocking layer includes two or more layers, different compositions of sputter gas may be applied during sputtering for each layer. When the light blocking layer includes two or more layers, different compositions of a sputtering target and a sputtering gas may be applied during sputtering for each layer.

In the case of the sputtering target, one target containing chromium may be applied, and two or more targets including one target containing chromium may be applied. A target containing chromium may contain 90 atomic percent or more chromium. A target containing chromium may contain 95 atomic percent or more chromium. A target containing chromium may contain 99 atomic percent or more chromium.

In the case of the sputtering gas, the composition of the sputtering gas may be adjusted in consideration of the composition of elements constituting each layer of the light-shielding layer, film quality of the light-shielding layer, and optical characteristics.

The sputter gas may include a reactive gas and an inert gas. By adjusting the content of the reactive gas in the sputter gas, it is possible to control the optical properties and film quality of the light-shielding layer to be formed. Reactive gases are CO ₂ , O ₂ , N ₂ and NO ₂ and the like. The reactive gas may further include other gases in addition to the gases described above.

By adjusting the content of the inert gas in the sputtering gas, it is possible to control the film quality of the light-shielding layer to be formed. The inert gas may include Ar, He and Ne, and the like. The inert gas may further include other gases in addition to the gases described above.

When forming the lower layer of the light blocking layer, a sputtering gas containing Ar, N2, He, and CO ₂ may be injected into the chamber. Specifically, a sputter gas having a sum of the flow rates of CO ₂ and N ₂ relative to the total flow rate of the sputter gas is 40% or more may be injected into the chamber. In this case, the lower layer of the light blocking layer may have desired crystal properties. Accordingly, the photomask and the blank mask may have the fifth amorphous index and the sixth amorphous index.

When forming the upper layer of the light blocking layer, a sputter gas containing Ar and N ₂ may be injected into the chamber. Specifically, a sputter gas having a flow rate of N ₂ of 30% or more relative to the total flow rate of the sputter gas may be injected into the chamber. In this case, the upper layer of the light blocking layer may have desired crystal characteristics. Accordingly, the photomask and the blank mask may have the fifth amorphous index and the sixth amorphous index.

Each gas constituting the sputter gas may be mixed and injected into the sputter chamber. Each gas constituting the sputter gas may be individually injected through different inlets in the sputter chamber.

A magnet may be disposed in the chamber to control the uniformity of film quality and in-plane optical characteristics of the light-shielding layer to be formed. Specifically, by placing the magnet on the back side of the sputtering target and rotating the magnet at a constant speed, a constant distribution of plasma can be maintained on the entire surface of the target. The magnet may be rotated at a speed of 50 to 200 rpm during film formation for each layer.

In the sputtering process, the T/S distance, which is the distance between the target and the substrate, and the angle between the substrate and the target may be adjusted. When forming each layer of the light blocking layer, the T/S distance may be 240 to 300 mm. In this case, the film formation speed can be stably controlled, and the uniformity of in-plane optical properties of the thin film to be formed can be improved. The angle between the substrate and the target may be 20 to 30 degrees. In this case, excessive increase in the internal stress of the thin film to be formed can be suppressed.

In the sputtering process, the rotational speed of the substrate to be deposited may be adjusted. When forming each layer of the light blocking layer, the rotational speed of the substrate to be formed may be 2 to 50 RPM. The rotation speed of the substrate may be 10 to 40 RPM. When the rotational speed of the substrate to be deposited is adjusted within this range, the light blocking layer may have desired crystal characteristics. Accordingly, the photomask and the blank mask may have the fifth amorphous index and the sixth amorphous index.

In addition, when the light blocking layer 30 is formed, the intensity of the voltage applied to the sputtering target may be adjusted. A discharge region including a plasma atmosphere in the chamber is formed by supplying a voltage to a target located in the sputtering chamber. By adjusting the strength of the voltage, the plasma atmosphere in the chamber can be adjusted together with the magnet to control the film quality of the film formed during sputtering.

The strength of the voltage applied to the sputtering target when the lower layer of the light blocking layer is formed may be 0.5 to 2 kW. The intensity of the voltage may be 1.0 to 1.8 kW. The intensity of the voltage may be 1.2 to 1.5 kW. The strength of the voltage applied to the sputtering target when the upper layer of the light blocking layer is formed may be 1 to 3 kW. The intensity of the voltage may be 1.3 to 2.5 kW. The intensity of the voltage may be 1.5 to 2.0 kW. In this case, the lower layer of the light blocking layer may have desired crystal properties. Accordingly, the photomask and the blank mask may have the fifth amorphous index and the sixth amorphous index.

A spectroscopic ellipse analyzer can be installed in the sputtering equipment. Through this, the film formation time can be controlled so that the light blocking layer 30 to be formed has desired optical characteristics. When forming the light shielding layer 30, the measurement method after installing the spectroscopic ellipse analyzer in the sputtering equipment is the same as when forming the phase inversion layer, so it is omitted.

When forming the lower layer of the light shielding layer 30, sputtering may be performed until the photon energy at the point where the phase difference between the P wave and the S wave of the reflected light measured by the spectroscopic ellipse analyzer is 140° is 1.6 to 2.2 eV. When forming the lower layer of the light shielding layer 30, sputtering may be performed until the photon energy at the point where the phase difference between the P wave and the S wave of the reflected light measured by the spectroscopic ellipse analyzer is 140° is 1.8 to 2.0 eV.

When the upper layer of the light blocking layer 30 is formed, sputtering may be performed until the photon energy at the point where the phase difference between the P wave and the S wave of the reflected light measured by the spectroscopic ellipse analyzer is 140° is 1.7 to 3.2 eV. When the upper layer of the light blocking layer 30 is formed, sputtering may be performed until the photon energy at the point where the phase difference between the P wave and the S wave of the reflected light measured by the spectroscopic ellipse analyzer is 140° is 2.5 to 3.0 eV.

As described above, the light blocking layer and the transparent substrate have different crystal characteristics. Accordingly, the light blocking layer and the transparent substrate may have different optical properties. Accordingly, the light blocking layer may have a high optical density.

In this case, the formed light blocking layer may be included in the blind pattern of the photomask to effectively block exposure light.

Manufacture of photomask

A photomask according to another embodiment of the implementation may be manufactured with the previously described blank mask 100 .

Specifically, the photomask may form a resist film (not shown) by coating the surface of the blank mask 100 with resist and then drying. The resist may be a positive resist or may be a negative resist. A resist film may be formed adjacent to the light blocking layer 30 . A resist film may be formed adjacent to the surface of another film located on the light blocking layer 30 .

A pattern may be formed by drawing a pattern on the resist film through EB or light irradiation, followed by heating and development. The thin film formed on the surface of the blank mask 100 may be etched using the formed resist pattern as an etching mask. The thin film to be etched may be the light blocking layer 30 . The thin film to be etched may be another thin film formed on the light blocking layer 30 . For the etching process, dry etching may be applied depending on the composition of the film to be etched. Chlorine-based gas and fluorine-based gas may be used as an etching gas applied to dry etching.

Thereafter, the resist film may be removed, and the phase shift layer and the light blocking layer may be etched according to the designed pattern shape. During etching, different etchants may be applied considering the etching characteristics of each thin film.

Since the first amorphous index has the above range, the phase shift layer and the transparent substrate have very similar crystal properties.

In addition, since the second amorphous index has the above range, the phase shift layer and the transparent substrate have very similar crystal properties.

In addition, since the third amorphous index has the above range, the phase shift layer and the transparent substrate have very similar crystal properties.

In addition, since the fourth amorphous index has the above range, the phase shift layer and the transparent substrate have very similar crystal properties.

Accordingly, optical distortion due to a difference in crystal characteristics between the phase shift layer and the transparent substrate may be minimized. In addition, it is easier to control the difference in etching degree due to the difference in crystal characteristics. That is, since the phase shift layer and the transparent substrate have similar crystal characteristics according to XRD analysis, the photomask may have improved optical performance.

In particular, since the transparent substrate and the phase shift layer have similar crystal characteristics, optical distortion generated at the interface between the transparent substrate and the phase shift layer is reduced when the transparent substrate and the phase shift layer directly contact each other. It can be.

In addition, since the fifth amorphous index has the above range, the light blocking layer and the transparent substrate have different crystal characteristics.

Since the sixth amorphous index has the above range, the light blocking layer and the transparent substrate have different crystal characteristics.

Accordingly, the light blocking layer may have improved light blocking performance.

Accordingly, the apparatus for manufacturing a semiconductor device according to the embodiment can reduce process errors due to optical distortion in exposure and development processes. Therefore, the apparatus for manufacturing a semiconductor device according to the embodiment can easily manufacture a semiconductor device having improved fine line width characteristics.

Hereinafter, specific embodiments will be described in more detail.

Production Example: Formation of phase inversion layer and light shielding layer

Example 1: A quartz material transparent substrate having a width of 6 inches, a length of 6 inches, and a thickness of 0.25 inches was disposed in a chamber of a DC sputtering equipment. A target containing molybdenum and silicon in an atomic ratio of 1:9 was placed in the chamber to form a T/S distance of 255 mm and an angle between the substrate and the target of 25 degrees. A magnet with a magnetic field of 40 mT was placed on the back of the target.

Thereafter, a sputtering gas mixed at a ratio of Ar:N ₂ :He = 10:52:38 was introduced into the chamber, and a sputtering process was performed while rotating the magnet at a sputtering voltage of 2.05kW. At this time, the rotational speed of the magnet was increased from the initial 100 rpm to a maximum of 155 rpm by 11 rpm per minute. The area where the thin film is formed was limited to an area set to a width of 132 mm in width and 132 mm in length of the surface of the transparent substrate. The sputtering process was performed until the photon energy at the point where the Del_1 value according to Equation A below is 0 is 2.0 eV, measured by a spectroscopic ellipse analyzer by applying an incident angle of 64.5 °.

[Equation A]

In Equation A, the DPS value means the phase difference between the P wave and the S wave when the phase difference between the P wave and the S wave of the reflected light is 180 ° or less, and when the phase difference between the P wave and the S wave of the reflected light exceeds 180 °, at 360 ° It means a value obtained by subtracting the phase difference between the P wave and the S wave.

After the sputtering, the surface of the phase shift layer of the blank mask was exposed to Excimer UV light having a wavelength of 172 nm. At this time, the output of the UV light was raised to a maximum of 9mW/cm ² by 3mW/cm ² per minute, and was maintained for 4 minutes at 9mW/cm ² power.

Thereafter, the blank mask was introduced into a heat treatment process chamber, annealed at 1Pa, and then naturally cooled. The temperature in the annealing process was raised from room temperature to a maximum of 400 °C at a rate of 50 °C per minute, and maintained at the maximum temperature for about 30 minutes. After natural cooling was completed, O ₂ gas in the chamber for heat treatment process was introduced into the chamber at a rate of 1 SLM for 30 minutes. At this time, the supply temperature of O ₂ was about 300°C.

A light blocking layer sputtering process was performed on the surface of the formed phase shift layer. Specifically, the transparent substrate on which the chromium target and the phase inversion layer were formed was disposed so that the T/S distance in the sputtering chamber was 255 mm and the angle between the substrate and the target was 25 degrees. A magnet with a magnetic field of 40 mT was placed on the back of the target.

A sputter gas having a flow rate in the chamber of Ar:N ₂ :He:CO ₂ =19:11:34:37 was injected. Thereafter, a sputtering voltage of 1.35 kW is applied, and while the magnet is rotated, sputtering is performed until the photon energy at the point where the phase difference between the P wave and the S wave is 140° measured by the spectroscopic ellipse analyzer is 1.8 to 2.0 eV, thereby removing the lower layer of the light shielding film. It was formed. A sputtering process was performed. At this time, the rotational speed of the magnet was increased from the initial 100 rpm to a maximum of 155 rpm by 11 rpm per minute.

After forming the lower layer of the light shielding layer, a sputter gas having a flow rate ratio of Ar:N ₂ =57:43 was injected into the chamber. Afterwards, a sputtering voltage of 1.85 kW was applied and the magnet was rotated. An upper layer of the light shielding layer was formed by performing sputtering until the photon energy at the point where the phase difference between the P wave and the S wave measured by the spectroscopic ellipse analyzer was 140° was 2.75 to 2.95 eV.

A total of two samples were prepared by applying the above film formation conditions.

Example 2: The sputtering process is performed under the same conditions as Example 1, but the magnet magnetic force is applied at 45 mT, and the process progress time is when the photon energy at the point where the value of Del_1 according to Equation A is 0 becomes 1.89 eV. carried out up to

Example 3: A sputtering process was performed under the same conditions as in Example 1, but the composition of the sputtering gas was changed at a ratio of Ar:N ₂ :He = 8:58:34.

Comparative Example 1: A quartz material transparent substrate having a width of 6 inches, a length of 6 inches, and a thickness of 0.25 inches was disposed in a chamber of a DC sputtering device. A target containing molybdenum and silicon in an atomic ratio of 1:9 was placed in the chamber to form a T/S distance of 255 mm and an angle between the substrate and the target of 25 degrees. A magnet with a magnetic field of 60 mT was placed on the back of the target.

Thereafter, a sputtering gas mixed at a ratio of Ar:N ₂ :He = 9:52:39 was introduced into the chamber, and a sputtering process was performed while rotating the magnet at a speed of 100 rpm and a sputtering voltage of 2 kW. The area where the thin film is formed was limited to an area set to a width of 132 mm in width and 132 mm in length of the surface of the transparent substrate. The sputtering process was performed until the photon energy at the point where Del_1 value according to Equation A was 0 reached 2.0 eV. UV light treatment and annealing treatment were not applied after film formation.

A light blocking layer sputtering process was performed on the surface of the formed phase shift layer. Specifically, the transparent substrate on which the chromium target and the phase inversion layer were formed was disposed so that the T/S distance in the sputtering chamber was 255 mm and the angle between the substrate and the target was 25 degrees. A magnet with a magnetic field of 60 mT was placed on the back of the target.

A sputter gas having a flow rate in the chamber of Ar:N ₂ :He:CO ₂ =19:11:34:37 was injected. Then, a sputtering voltage of 1.35 kW is applied, and while the magnet is rotated at 100 rpm, sputtering is performed until the photon energy at the point where the phase difference between the P wave and the S wave is 140°, measured by the spectroscopic ellipse analyzer, is 1.8 to 2.0 eV. The lower layer was formed into a film. A sputtering process was performed.

After forming the lower layer of the light shielding layer, a sputter gas having a flow rate ratio of Ar:N2 = 57:43 in the chamber was injected. Afterwards, a sputtering voltage of 1.85 kW was applied and the magnet was rotated. An upper layer of the light shielding layer was formed by performing sputtering until the photon energy at the point where the phase difference between the P wave and the S wave measured by the spectroscopic ellipse analyzer was 140° was 2.75 to 2.95 eV.

Comparative Example 2: A sputtering process was performed under the same conditions as Comparative Example 1, but a magnet force of 20 mT was applied. In addition, no additional heat treatment process was applied.

Before forming the light-shielding layer on the samples, the distribution of Del_2 values when PE ₁ was 1.5 eV and PE ₂ was 5.0 eV was measured using a spectroscopic ellipse analyzer (manufactured by Nano-View Co., Ltd. MG-PRO) installed in the sputtering device. . Specifically, after setting the angle of the incident light to 64.5 on the surface of the phase shift film on which the film formation for each example and comparative example was completed, the phase difference between the P wave and the S wave according to the photon energy was measured and converted into Del_2 value according to Equation B. did The results are shown in Table 2 below.

Evaluation example: XRD analysis

In the blank masks prepared in Examples 1 to 3 and Comparative Example 1 and Comparative Example 2, normal mode XRD analysis and fixed mode XRD analysis were performed through the lower surface of the transparent substrate. Further, in the blank mask, normal mode XRD analysis and fixed mode XRD analysis were performed through the light blocking layer. Thereafter, the light blocking layer included in the blank mask was removed by an etching and cleaning process, and the phase shift film was exposed.

In this way, normal mode XRD analysis and fixed mode XRD analysis were performed through the exposed phase inversion layer.

The normal mode XRD analysis was performed under the following conditions.

Device name: Rigaku 社 smartlab

x-ray source : Cu target

x-ray information: wavelength 1.542 nm, 45 kV, 200 mA

(Θ-2Θ) measurement range: 10~100 ˚

Step : 0.05˚

Speed : 5˚/min

The fixed mode XRD analysis was performed under the following conditions.

Device name: Rigaku 社 smartlab

x-ray source : Cu target

x-ray information: wavelength 1.542 nm, 45 kV, 200 mA

X-ray generator emission angle: 1°

(Θ-2Θ) measurement range: 10~100 ˚

Step : 0.05˚

Speed : 5˚/min

Evaluation Example: Measurement of phase difference and transmittance

For the examples and specimens described in the previous preparation example, the light-blocking layer was removed through etching in the same manner as in the thermal fluctuation measurement. Phase difference and transmittance were measured using a retardation/transmittance meter (Lasertec MPM193 product). Specifically, by using an ArF light source (wavelength: 193 nm), light is irradiated to the area where the phase shift layer is formed and the area where the phase shift layer is not formed on each specimen, and the phase difference and transmittance difference value between the light passing through both areas was calculated and listed in Table 2 below.

Evaluation Example: Contrast and CD value measurement

After forming a photoresist film on the surface of the phase reversal layer of the samples for each example and comparative example, a dense square pattern was exposed on the surface of the photoresist film using Nuflare's EBM 9000 model. The target CD value of the square pattern was set to 400 nm (4X). Then, after developing the pattern on the photoresist film of each specimen, the light-shielding layer and the phase reversal layer were etched according to the developed pattern shape using the Tetra X model of Applied Material. After that, the photoresist pattern was removed.

Contrast and normalized CD value of the pattern developed during the wafer exposure process according to the Del_1 value and Del_2 value of the phase shift layer using the AIMS 32 model of Carl Zeiss for the samples for each example and comparative example including the phase shift layer pattern was measured and calculated. During measurement and calculation, the numerical aperture (NA) was set to 1.35, the illumination system was set to crosspole 30X, outer sigma 0.8, and in/out sigma ratio 85%. The measured data are listed in Table 3 below.

AI1 AI2 AI3 AI4 AI5 AI6 Example 1 1.00 1.02 1.01 0.99 0.96 1.0938 Example 2 1.01 1.02 1.02 0.99 0.95 1.10 Example 3 1.00 1.03 1.02 1.00 0.93 1.11 Comparative Example 1 0.97 0.96 0.94 1.05 0.99 1.05 Comparative Example 2 0.94 0.95 0.93 1.02 0.98 1.05

magnetic field (mT) Photon energy at the point where Del_1 value is 0 (eV) Photon energy at the point where Del_2 is 0 (eV) Transmittance (%) Phase difference (°) Example 1 40 2.00 4.44 6.1 178.5 Example 2 45 1.89 4.31 5.4 186.1 Example 3 35 2.09 4.65 6.9 172.4 Comparative Example 1 60 1.65 3.84 3.4 209.1 Comparative Example 2 20 2.17 4.80 7.8 166.0

normalized contrast Normalized CD (nm) Example 1 1.000 0.99 Example 2 0.989 1.01 Example 3 0.959 1.03 Comparative Example 1 0.929 1.06 Comparative Example 2 0.883 1.10

In Table 1, the TFT1 and TFT2 values for each measurement condition in Examples 1 to 3 all showed values of 0.25um/100 ° C or less, but the TFT1 and TFT2 values for each measurement condition in Comparative Examples 1 and 2 were all Values greater than 0.25um/100°C were shown. This indicates that thermal fluctuations of the thin film included in the blank mask can be controlled by controlling process conditions during sputtering.

In Table 2, in Examples 1 to 3 in which the magnetic field was applied within the range of 30 to 50 mT, the photon energy at the point where the Del_1 value was 0 was within the range of 1.8 to 2.15 eV, but the magnetic field was less than 30 mT or greater than 50 mT Comparative Example 1 and 2 showed that the photon energy at the point where the Del_1 value is 0 is not included within the range of 1.8 to 2.15 eV. Through this, it can be seen that the distribution of the Del_1 value according to the photon energy of the phase shift layer can be controlled by adjusting the magnetic force of the magnet in the sputtering process.

Further, in Examples 1 to 3 in which an additional heat treatment process was performed after film formation, the photon energy at the point where the Del_2 value was 0 was within the range of 4 to 4.75 eV, but in Comparative Examples 1 and 2, in which no additional heat treatment process was performed after film formation, It was found that the photon energy at the point where Del_2 value is 0 is less than 4 or more than 4.75. This means that the distribution of the Del_2 value according to the photon energy of the phase shift layer can be controlled by applying a heat treatment process after the sputtering film formation.

The transmittance of Examples 1 to 3 was within the range of 5.4 to 6.9% and the phase difference was within the range of 170 to 190 °, but Comparative Example 1 had a transmittance of less than 4% and a phase difference of 200 ° or more, Comparative Example 2 was measured to have a transmittance of 7.5% or more and a phase difference of less than 170°. Through this, the phase shift layer in which the photon energy at the point where Del_1 value is 0 and the photon energy at the point where Del_2 value is 0 are adjusted within the set range has the desired transmittance (6%) and phase difference for short-wavelength exposure light. It can be seen that the optical properties are close to (180 degrees).

In Table 3, Examples 1 to 3, in which the photon energy at the point where Del_1 is 0 and the photon energy at the point where Del_2 is 0, fall within the range of 4 to 4.75 eV, are normalized. Comparative Examples 1 and 2 exhibited a normalized contrast of less than 0.93 and a normalized CD value of 1.06 or more, while a normalized contrast of 0.95 or more and a normalized CD value of 1.03 or less. Through this, the thermal fluctuation is controlled, and the photon energy at the point where the Del_1 value is 0 and the photon energy at the point where the Del_2 value is 0 are adjusted within the set range, so that the phase inversion layer achieves a higher level of resolution during pattern exposure. know what you have

Although the preferred embodiments have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the embodiments defined in the following claims are also within the scope of the present invention. it belongs

100: blank mask 200: photo mask
10: transparent substrate
20: phase inversion layer 21: phase difference adjustment layer 22: protective layer
30: light shield
60: X-ray generator (light source)
70: detector

Claims (12)

light source; and
A photo mask through which light from the light source is incident, selectively transmits the incident light, and exits the incident light to a semiconductor wafer;
The photo mask may include a transparent substrate; a phase inversion layer disposed on the transparent substrate; And a light blocking layer disposed on the phase inversion layer,
The transparent substrate is a synthetic quartz substrate,
The phase shift layer includes a phase difference adjustment layer positioned on the transparent substrate and a protective layer positioned on the phase difference adjustment layer,
The phase inversion layer includes a transition metal, silicon, oxygen and nitrogen,
The retardation adjustment layer contains 3 to 10 atomic% of a transition metal, 20 to 50 atomic% of silicon, 2 to 10 atomic% of oxygen, and 40 to 60 atomic% of nitrogen,
The protective layer contains 0.5 to 5 atomic % of a transition metal, 10 to 50 atomic % of silicon, 10 to 50 atomic % of oxygen and 20 to 40 atomic % of nitrogen,
The photomask is analyzed by normal mode XRD,
In the normal mode XRD analysis, the maximum peak of the X-ray intensity measured after reflection in the direction of the phase inversion layer is located between 2θ of 15 ° and 30 °,
In the normal mode XRD analysis, the maximum peak of the X-ray intensity measured after reflection in the direction of the transparent substrate is located between 2θ of 15 ° and 30 °,
a semiconductor device manufacturing apparatus having a first amorphous index (AI1) represented by Equation 1 below of 0.98 to 1.02;
[Equation 1]

In Equation 1 above,
XM1 is the maximum value of X-ray intensity measured when the normal mode XRD analysis is performed on the phase inversion layer;
XQ1 is the maximum value of X-ray intensity measured when the normal mode XRD analysis is performed on the lower surface of the transparent substrate.
transparent substrate; a phase inversion layer disposed on the transparent substrate; and a light blocking layer disposed on at least a portion of the phase shift layer;
The transparent substrate is a synthetic quartz substrate,
The phase shift layer includes a phase difference adjustment layer positioned on the transparent substrate and a protective layer positioned on the phase difference adjustment layer,
The phase inversion layer includes a transition metal, silicon, oxygen and nitrogen,
The retardation adjustment layer contains 3 to 10 atomic% of a transition metal, 20 to 50 atomic% of silicon, 2 to 10 atomic% of oxygen, and 40 to 60 atomic% of nitrogen,
The protective layer contains 0.5 to 5 atomic % transition metal, 10 to 50 atomic % silicon, 10 to 50 atomic % oxygen and 20 to 40 atomic % nitrogen,
The photomask is analyzed by normal mode XRD,
In the normal mode XRD analysis, the maximum peak of the X-ray intensity measured after reflection in the direction of the phase inversion layer is located between 2θ of 15 ° and 30 °,
In the normal mode XRD analysis, the maximum peak of the X-ray intensity measured after reflection in the direction of the transparent substrate is located between 2θ of 15 ° and 30 °,
A photomask having a first amorphous index (AI1) represented by Equation 1 below of 0.98 to 1.02;
[Equation 1]

In Equation 1 above,
XM1 is the maximum value of X-ray intensity measured when the normal mode XRD analysis is performed on the phase inversion layer;
The XQ1 is the maximum value of X-ray intensity measured when the normal mode XRD analysis is performed on the lower surface of the transparent substrate.
According to claim 2,
The protective layer includes a region in which the ratio of the nitrogen content to the oxygen content in the thickness direction belongs to 0.4 to 2, and the region has a thickness of 30 to 80% when considering the total thickness of the protective layer as 100%.
According to claim 2,
When the thickness of the phase inversion layer is 100%, the thickness of the protective layer is 4 to 9%,
The thickness of the protective layer is 25 Å or more and 80 Å or less,
The retardation adjustment layer has a refractive index of 2 to 4 for ArF light and an extinction coefficient for ArF light of 0.3 to 0.7.
According to claim 2,
The photomask is analyzed by fixed mode XRD,
In the fixed mode XRD analysis, the first peak, which is the maximum peak of the X-ray intensity measured after reflection in the direction of the phase inversion layer, has 2θ between 15 ° and 25 °,
In the fixed mode XRD analysis, the second peak, which is the maximum peak of the X-ray intensity measured after reflection in the direction of the transparent substrate, has 2θ between 15 ° and 25 °,
a photomask having a second amorphous index (AI2) represented by Equation 2 below of 0.9 to 1.1;
[Equation 2]

In Equation 2 above,
XM2 is the intensity value of the first peak,
The XQ2 is an intensity value of the second peak.
According to claim 2,
A photomask having a third amorphous index (AI3) represented by Equation 3 below of 0.9 to 1.1;
[Equation 3]

In Equation 3 above,
AM1 is an area where 2θ is between 15° and 30° in the X-ray intensity graph measured after reflection when normal mode XRD analysis is performed on the phase inversion layer;
The AQ1 is an area in a region where 2θ is between 15° and 30° in the X-ray intensity graph measured after reflection when normal mode XRD analysis is performed on the lower surface of the transparent substrate.
According to claim 6,
A photo mask having a fourth amorphous index (AI4) represented by Equation 4 below of 0.9 to 1.1;
[Equation 4]

In Equation 4 above,
XM4 is the reflected X-ray intensity when 2θ is 43 ° in the normal mode XRD analysis conducted on the phase inversion layer,
The XQ4 is the reflected X-ray intensity when 2θ is 43° in the normal mode XRD analysis conducted on the lower surface of the transparent substrate.
transparent substrate; And a phase shift layer disposed on the transparent substrate; a blank mask including,
The transparent substrate is a synthetic quartz substrate,
The phase shift layer includes a phase difference adjustment layer positioned on the transparent substrate and a protective layer positioned on the phase difference adjustment layer,
The phase inversion layer includes a transition metal, silicon, oxygen and nitrogen,
The blank mask is analyzed by normal mode XRD,
In the normal mode XRD analysis, the maximum peak of the X-ray intensity measured after reflection in the direction of the phase inversion layer is located between 2θ of 15 ° and 30 °,
In the normal mode XRD analysis, the maximum peak of the X-ray intensity measured after reflection in the direction of the transparent substrate is located between 2θ of 15 ° and 30 °,
A blank mask having a first amorphous index (AI1) represented by Equation 1 below of 0.98 to 1.02;
[Equation 1]

In Equation 1 above,
XM1 is the maximum value of X-ray intensity measured when the normal mode XRD analysis is performed on the phase inversion layer;
The XQ1 is the maximum value of X-ray intensity measured when the normal mode XRD analysis is performed on the lower surface of the transparent substrate.
According to claim 8,
The phase shift layer is a blank mask having a photon energy of 1.8 to 2.15 eV at a point where Del_1 value according to Equation A below is 0 measured by a spectroscopic ellipse analyzer by applying an incident angle of 64.5 °;
[Equation A]

In Equation A, the DPSp value is the phase difference between the P wave and the S wave when the phase shift layer is measured with a spectroscopic ellipse analyzer by applying an incident angle of 64.5 ° and the phase difference between the P wave and the S wave of the reflected light is 180 ° or less. , If the phase difference between the P wave and the S wave of the reflected light exceeds 180 °, the value obtained by subtracting the phase difference between the P wave and the S wave from 360 °,
The PE value is a photon energy within the range of 1.5 to 3.0 eV, when PE ₁ is 1.5 eV and PE ₂ is 3 eV.
According to claim 9,
In the phase inversion layer, when the photon energy measured by the spectroscopic ellipse analyzer by applying an incident angle of 64.5° is PE ₁ value 3.0 eV and PE ₂ value 5.0 eV, Del_2 represented by Equation B below is 0. A blank mask with a photon energy of 3.9 to 4.7 eV;
[Equation B]

In Equation B, the DPS value is the P wave when the phase difference between the P wave and the S wave of the reflected light is 180 ° or less when the surface of the phase shift layer is measured with a spectroscopic ellipse analyzer by applying an incident angle of 64.5 ° on the protective layer. and a phase difference between the S waves, and if the phase difference between the P wave and the S wave of the reflected light exceeds 180°, it is a value obtained by subtracting the phase difference between the P wave and the S wave from 360°, and the PE value is the photon within the PE ₁ to PE ₂ range. It is energy.
transparent substrate; a phase inversion layer disposed on the transparent substrate; And a blank mask including a light blocking layer disposed on the phase shift layer,
The transparent substrate is a synthetic quartz substrate,
The light blocking layer contains chromium and nitrogen,
When normal mode XRD analysis is performed through the light-blocking layer, the X-ray intensity peak measured after reflection has a maximum value between 2θ of 15 ° and 30 °,
When the XRD common mode analysis is performed through the lower surface of the transparent substrate, the X-ray intensity peak measured after reflection has a maximum value at 2θ between 15 ° and 30 °,
The blank mask has a fifth amorphous index (AI5) represented by Equation 5 below of 0.9 to 0.97;
[Equation 5]

In Equation 5 above,
XC1 is the maximum value of the X-ray intensity measured through the light-shielding layer,
XQ1 is the maximum value of X-ray intensity measured through the lower surface of the transparent substrate.
According to claim 11,
A blank mask having a sixth amorphous index (AI6) represented by Equation 6 below of 1.05 to 1.4;
[Equation 6]

In Equation 6 above,
XC4 is the reflected X-ray intensity when 2θ is 43° when the normal mode XRD analysis is performed in the direction of the light-shielding layer;
The XQ4 is the reflected X-ray intensity when 2θ is 43° when the normal mode XRD analysis is performed in the direction of the lower surface of the transparent substrate.

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