KR102349368B1 - Apparatus for manufacturing semiconductor device - Google Patents

Abstract

Disclosed is a semiconductor device manufacturing apparatus comprising a light source and a photomask. The photomask comprises a transparent substrate, a phase shift film disposed on the transparent substrate, and a light blocking film disposed on the phase shift film. The phase shift film contains 1 to 10 atomic% of a transition metal. When a PE_1 value is 1.5 eV, and a PE_2 value is a minimum value among photon energies at a point where a Del_1 value expressed by equation 1 becomes 0, the photomask has an average value of Del_1 of 85 to 100 °/eV. In the equation 1, after removing the light blocking film from the photomask, when the phase shift film surface is measured with a spectral ellipse analyzer at an incident angle of 64.5°, if the phase difference between a P wave and an S wave of reflected light is 180° or less, a DPS_p value is the phase difference between the P wave and the S wave, and if the phase difference exceeds 180°, the DPS_p value is a value obtained by subtracting the phase difference between the P wave and the S wave from 360°. A PE value is the photon energy of the incident light within the range of PE_1 to PE_2. The semiconductor device manufacturing apparatus has desired optical characteristics with respect to light of a short wavelength while the phase shift film has a thin thickness.

Description

Semiconductor device manufacturing apparatus {APPARATUS FOR MANUFACTURING SEMICONDUCTOR DEVICE}

The embodiment relates to an apparatus for manufacturing a semiconductor device, a photomask included therein, and a blank mask for manufacturing the photomask.

BACKGROUND ART 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 a lithography technique, which is a technique for developing a circuit pattern on a wafer surface using a photomask, is further emphasized.

In order to develop a miniaturized circuit pattern, a shorter wavelength of an exposure light source used in an exposure process is required. Recently used exposure light sources include ArF excimer lasers (wavelength 193 nm) and the like.

On the other hand, the photomask includes a binary mask, a phase shift mask, and the like.

The binary mask has a structure in which a light blocking layer pattern is formed on a transparent substrate. In the binary mask, the pattern is exposed on the resist film on the wafer surface by transmitting the light-shielding portion including the light-shielding layer and blocking the exposure light. However, in the binary mask, as the pattern becomes finer, a problem may occur in the fine pattern phenomenon due to diffraction of light generated at the edge of the transmission part in the exposure process.

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

Domestic Registered Patent No. 10-1360540 US Patent Publication No. 2004-0115537 Japanese Patent Application Laid-Open No. 2018-054836

SUMMARY An embodiment is to provide an apparatus for manufacturing a semiconductor device capable of easily forming a fine pattern and having excellent durability against exposure and cleaning processes, a photomask included therein, and a blank mask for manufacturing the photomask.

An apparatus for manufacturing a semiconductor device according to an embodiment includes a light source and a photomask to which light from the light source is incident, to filter the incident light, and to emit the light to a semiconductor wafer.

The photo mask may include a transparent substrate; a phase shift film disposed on the transparent substrate; and a light blocking film disposed on the phase shift film.

The phase shift layer contains 1 to 10 atomic % of the transition metal.

In the photomask, when the PE ₁ value is 3.0 eV and the PE ₂ value is 5.0 eV, the photon energy of the incident light at the point where Del_1 expressed by Equation 1 below is 0 is 4.0 to 5.0 eV.

[Equation 1]

In Equation 1 above,

The DPSp value is, when the light-shielding film is removed from the photomask and the surface of the phase shift film is measured with a spectral ellipse analyzer by applying an incident angle of 64.5°, if the phase difference between the P-wave and S-wave of the reflected light is 180° or less, the P It is the phase difference between the wave and the S wave, and when 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 the photon energy of the incident light within the range of _{PE 1} to PE _{2 .}

A blank mask according to an embodiment includes a transparent substrate; a phase shift film disposed on the transparent substrate; and a light blocking film disposed on the phase shift film.

The phase shift layer contains 1 to 10 atomic % of the transition metal.

In the blank mask, when the PE ₁ value is 3.0 eV and the PE ₂ value is 5.0 eV, the photon energy of the incident light at the point where Del_2 is 0 expressed in Equation 2 below is 4.0 to 5.0 eV.

[Equation 2]

In Equation 2 above,

The DPS value is, after removing the light blocking film from the blank mask, when the phase shift film surface is measured with a spectral ellipse analyzer by applying an incident angle of 64.5°, if the phase difference between the P wave and the S wave of the reflected light is 180° or less, the P It is the phase difference between the wave and the S wave, 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 the photon energy of the incident light within the range of _{PE 1} to PE _{2 .}

In the blank mask, when the PE ₁ value is 1.5 _{eV and the PE 2} value is 3.0 eV, the photon energy of the incident light at the point where Del_2 is 0 may be 1.7 to 2.3 eV.

A semiconductor device manufacturing apparatus according to an embodiment includes a light source and a photomask to which light from the light source is incident, to filter the incident light, and to emit the light to a semiconductor wafer.

The photo mask may include a transparent substrate; a phase shift film disposed on the transparent substrate; and a light blocking film disposed on the phase shift film.

The phase shift layer contains 1 to 10 atomic % of the transition metal.

In the photomask, when the PE ₁ value is 1.5 eV and the PE ₂ value is the minimum value among photon energies at the point where the Del_1 value expressed in Equation 1 becomes 0, the photomask is expressed by Equation 1 The average value of Del_1 is 85 to 100°/eV.

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

The phase shift layer contains 1 to 10 atomic % of the transition metal.

In the blank mask, when the PE ₁ value is 1.5 eV and the PE ₂ value is the minimum value among the photon energies of the incident light at the point where the Del_2 value expressed in Equation 2 becomes 0, the value of Del_2 expressed in Equation 2 is The average value is 85 to 100°/eV.
In the blank mask, when the PE ₁ value is 1.5 _{eV and the PE 2} value is 5.0 eV, the maximum value of Del_2 expressed by Equation 2 may be 130 to 220°/eV.

In the blank mask, the PE ₁ value is the minimum value among photon energies of the incident light at the point where the Del_2 value becomes 0, and the PE ₂ value is the maximum value among the photon energies of the incident light at the point where the Del_2 value becomes 0. , the average value of Del_2 expressed by Equation 2 may be -75 to -50°/eV.

In the blank mask, the PE ₁ value is the maximum value among photon energies of the incident light at the point where the Del_2 value becomes 0. When the PE ₂ value is 5.0 eV, the average value of Del_2 expressed by Equation 2 is 40 to 120°/eV.

A semiconductor device manufacturing apparatus according to an embodiment includes a light source and a photomask to which light from the light source is incident, to filter the incident light, and to emit the light to a semiconductor wafer.

The photo mask may include a transparent substrate; a phase shift film disposed on the transparent substrate; and a light blocking film disposed on the phase shift film.

The phase shift layer contains 1 to 10 atomic % of the transition metal.

In the photomask, when the PE ₁ value is 1.5 _{eV and the PE 2} value is 5.0 eV, the maximum value of Del_1 expressed in Equation 1 in the photomask is 80 to 250°/eV.

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

In the blank mask, when the PE ₁ value is 1.5 _{eV and the PE 2} value is 5.0 eV, the maximum value of Del_2 expressed by Equation 2 is 80 to 250°/eV.

The blank mask may have a photon energy of 4.5 eV or more at a point where the Del_2 is a maximum value.

The phase shift film may include a phase difference adjustment layer and a protective layer disposed on the phase difference adjustment layer.

The phase shift layer may further include silicon, oxygen, and nitrogen.

The phase difference adjusting layer may contain 40 to 60 atomic % nitrogen.

The protective layer may contain 20 to 40 atomic % nitrogen.

The passivation layer may include a region in which a ratio of nitrogen content to oxygen content is 0.4 to 2 in a thickness direction, and the region may have a thickness of 30 to 80% of the total thickness of the passivation layer.

A ratio of the thickness of the passivation layer to the thickness of the phase shift layer may be 0.04 to 0.09.

The thickness of the passivation layer may be 25 Å or more and 80 Å or less.

The retardation adjusting layer may have a refractive index of 2 to 4 for light having a wavelength of 200 nm or less, and an extinction coefficient of 0.3 to 0.7 for light having a wavelength of 200 nm or less.

The retardation adjusting layer may have a refractive index of 2 to 4 for light having a wavelength of 193 nm, and an extinction coefficient of 0.3 to 0.7 for light having a wavelength of 193 nm.

The passivation layer may have a refractive index of 1.3 to 2 for light having a wavelength of 200 nm or less, and an extinction coefficient of 0.2 to 0.4 for light having a wavelength of 200 nm or less.

The passivation layer may have a refractive index of 1.3 to 2 for light having a wavelength of 193 nm, and an extinction coefficient of 0.2 to 0.4 for light having a wavelength of 193 nm.

The light blocking layer may include chromium, oxygen, nitrogen, and carbon, and may contain 44 to 60 atomic % of chromium.

In the blank mask, the phase shift film and the light blocking film may be included in a multilayer, and an optical density of the multilayer for light having a wavelength of 200 nm or less may be 3 or more.

In the blank mask, the phase shift layer and the light blocking layer may be included in a multilayer, and an optical density of the multilayer with respect to light having a wavelength of 193 nm may be 3 or more.

A photomask according to another embodiment is manufactured using the blank mask.

The apparatus for manufacturing a semiconductor device according to the embodiment may have a desired optical characteristic with respect to a light source having a short wavelength while being thin. In addition, fluctuations in the optical properties of the phase shift film that occur in the process of forming the protective layer on the surface of the phase shift film are suppressed, so it is possible to reduce the error in the pattern line width developed in the exposure process, and the phase according to the repeated exposure process and cleaning process Damage to the inversion film may be suppressed and durability may be improved.

1 is a semiconductor device manufacturing apparatus according to an embodiment of the present specification.
2 is a conceptual diagram showing the principle of measuring the phase difference between the P wave and the S wave of the reflected light of the phase shift film using a spectral elliptic analyzer.
3 is a conceptual diagram illustrating a blank mask manufactured according to another embodiment of the present specification.
Figure 4 is a graph measuring the DPS value described in Equation 2 for the photon energy of Examples 1 to 3;
5 is a graph of measuring Del_2 values of Equation 2 with respect to photon energy of Examples 1 to 3;
6 is a graph measuring the DPS value described in Equation 2 for the photon energy of Comparative Examples 1 and 2;
7 is a graph of measuring Del_2 values of Equation 2 with respect to photon energy of Comparative Examples 1 and 2;

Hereinafter, the embodiments will be described in detail so that those of ordinary skill in the art can easily carry out the embodiments. However, the embodiment may be implemented in various different forms and is not limited to the embodiment described herein.

As used herein, the terms "about," "substantially," and the like, are used in a sense at or close to the numerical value when the manufacturing and material tolerances inherent in the stated meaning are presented, and to aid understanding of embodiments. It is used to prevent an unconscionable infringer from using the mentioned disclosure in an unreasonable way.

Throughout this specification, the term "combination of these" included in the expression of the Markush form means one or more mixtures or combinations selected from the group consisting of the components described in the expression of the Markush form, and the components It is meant to include 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”, “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 B is located on A while another layer is located in between, and B is located in contact with the surface of A It is not construed as being limited to

In the present specification, unless otherwise specified, the expression “a” is interpreted as meaning including “a” or “plural” as interpreted in context.

In this specification, room temperature means 25 °C.

In this specification, the transmissive part means a region that does not include a phase shift film on the surface of the photomask on which a pattern is formed on the transparent substrate and transmits exposure light, and the semi-transmissive part means a region that transmits attenuated exposure light including the phase shift film do.

In this specification, the incident angle means an angle formed by the incident light of the spectral elliptic analyzer and the normal line of the phase shift film.

A semiconductor device can be manufactured by forming an exposure pattern on a semiconductor wafer. Specifically, if a photomask including a designed pattern is placed on a semiconductor wafer having a resist layer applied thereto and then exposed through a light source, the resist layer of the semiconductor wafer forms a designed pattern after treatment with a developing solution. .

As semiconductors are highly integrated, more miniaturized circuit patterns are required. In order to form a miniaturized pattern on a semiconductor wafer, exposure light having a shorter wavelength than conventional exposure light may be applied. The exposure light for forming the finer pattern includes, for example, an ArF excimer laser (wavelength 193 nm).

In order to develop a finer circuit pattern with excellent resolution through the semiconductor device manufacturing device, the optical properties of the photomask included in the manufacturing device, for example, the phase difference and transmittance of the phase shift film in the photomask are precisely controlled, and the phase It is necessary to further reduce the thickness of the inversion film.

Meanwhile, in order to improve durability of the phase shift film, a protective layer may be formed on the surface of the phase shift film. As a method of forming a protective layer on the surface of the phase shift film, a method of forming a protective layer without applying a separate process through a natural oxidation reaction, a method of forming a separate layer on the surface of the phase shift film, heat treatment on the surface of the phase shift film How to apply the process, etc.

In the natural oxidation process, optical properties in the in-plane direction of the phase shift film may not be constant, and the durability of the phase shift film may be somewhat insufficient. In the process of forming a separate layer on the surface of the phase shift film or the heat treatment process, optical properties of the entire phase shift film may be changed due to the formation of the protective layer.

The inventors of the embodiment apply a controlled magnetic field during sputtering to form a phase shift film having a specific distribution of the phase difference between the P wave and the S wave with respect to the amount of photon energy change measured with a spectral elliptic analyzer. It was confirmed that a phase shift film could be provided. In addition, when the protective layer is formed with a specific distribution of the phase difference between the P wave and the S wave with respect to the photon energy change amount by precisely controlling the content of each element in the thickness direction of the protective layer formed on the surface of the phase shift film, it is caused by the protective layer It was confirmed that fluctuations in the optical properties of the entire phase shift film can be more effectively suppressed. Accordingly, the inventors of the embodiment completed the embodiment based on the above content.

Hereinafter, implementations are described in more detail.

1 is a conceptual diagram illustrating an apparatus for manufacturing a semiconductor device manufactured according to an exemplary embodiment. 2 is a conceptual diagram illustrating the principle of measuring the phase difference between the P wave and the S wave of the reflected light of the phase shift film using a spectral ellipse analyzer. An embodiment will be described in detail below with reference to FIGS. 1 and 2 .

In order to achieve the above object, in the semiconductor device manufacturing apparatus 1000 according to an embodiment disclosed herein, a light source 300 and light from the light source 300 are incident, and the incident light is filtered to form a semiconductor device. It includes a photomask 200 emitting to the wafer 500 .

The light source 300 is a device capable of generating exposure light having a short wavelength. The exposure light may be light having a wavelength of 200 nm or less. Specifically, the exposure light may be ArF light having a wavelength of 193 nm.

The semiconductor device manufacturing apparatus 1000 may further include a lens 400 . In the semiconductor device manufacturing apparatus 1000 , the lens 400 may be positioned between the photomask 200 and the semiconductor wafer 500 . The lens 400 has a function of reducing the shape of the circuit pattern on the photomask and transferring it onto the semiconductor wafer. The lens 400 is not limited as long as it can be generally applied to an ArF semiconductor wafer exposure process. Illustratively, the lens 400 may be a lens composed of _{calcium fluoride (CaF 2 ).}

The photomask 200 includes a transparent substrate 10 , a phase shift film 20 disposed on the transparent substrate 10 , and a light blocking film 30 disposed on the phase shift film 20 .

The transparent substrate 10 in the photomask 200 serves to transmit the exposure light to the thin film formed on the transparent substrate 10 .

The phase shift film 20 in the photomask 200 may include a pattern to be transferred. The light blocking film 30 in the photomask 200 may include a pre-designed pattern.

The phase shift layer 20 attenuates the exposure light passing through the phase shift layer 20 and adjusts the phase difference of the exposure light to improve the resolution of the pattern to be developed.

The phase shift film 20 may include a phase difference adjusting layer. The phase shift film 20 may include a phase difference adjustment layer and a protective layer on the phase difference adjustment layer. The description of the phase difference adjusting layer and the protective layer is omitted because it overlaps with the following contents.

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

The photomask 200 may be manufactured as a blank mask 100 to be described below.

Specific descriptions of the layer structure, optical properties, composition and sputtering method, patterning method, etc. of the transparent substrate 10, the phase shift film 20 and the light blocking film 30 in the photomask 200 are blank mask and photomask below. Since it overlaps with the description of the manufacturing method, it is omitted.

In the semiconductor device manufacturing equipment 1000 , the photomask 200 has a photon energy of incident light at a point where Del_1 expressed by Equation 1 below is 0 when _{PE 1} is 3.0 eV and PE _{2 is 5.0 eV.} to 5.0 eV.

[Equation 1]

In Equation 1 above,

The DPSp value is, when the light-shielding film is removed from the photomask and the surface of the phase shift film is measured with a spectral ellipse analyzer by applying an incident angle of 64.5°, if the phase difference between the P-wave and S-wave of the reflected light is 180° or less, the P It is the phase difference between the wave and the S wave, and when 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 the photon energy of the incident light within the range of _{PE 1} to PE _{2 .}

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 spectral elliptic analyzer, the optical characteristics of each layer of the thin film to be measured can be measured. Specifically, when the photon energy of the incident light is relatively low, the incident light forms a long wavelength, so that the optical characteristics of the lower layer of the measurement target thin film can be measured. When the photon energy of the incident light is relatively high, the incident light forms a short wavelength, so that the optical characteristics of the upper layer of the measurement target thin film can be measured.

The inventors of the embodiment set the photon energy value of the incident light to a relatively high range at a fixed incident angle (θ) with respect to the phase shift film or the phase shift film pattern, so that the P wave (P`) and the S wave of <sub>the reflected light (L r )</sub> By measuring the distribution of the phase difference (Δ) between (S`), it was experimentally confirmed that the optical properties of the upper layer of the phase shift film, specifically the protective layer, could be measured. In addition, the inventors of the embodiment experimentally confirmed that the phase shift film in which the Del_1 value measured by the above method is controlled within a certain range has a stable durability while having little influence on optical properties fluctuation due to the formation of the protective layer.

When the PE ₁ value is 3.0 eV and the PE ₂ value is 5.0 eV, the Del_1 value is the content of each element in the thickness direction of the protective layer, UV light irradiation conditions before heat treatment process, temperature applied during heat treatment process, temperature rise rate, heat treatment process It can be controlled by adjusting various factors such as the composition and content of the atmosphere gas, and the thickness of the protective layer. In the embodiment, the photon energy value of incident light is relatively high by controlling the content of each element in the thickness direction of the protective layer through a UV light irradiation process and a heat treatment process in which detailed process conditions are controlled before the formation of the protective layer. Controlled the distribution of Del_1 values in the range.

A detailed description of the process for controlling the distribution of the Del_1 value in the range where the photon energy value of the incident light is relatively high is omitted because it overlaps with the description of the method for manufacturing the phase shift film below.

The distribution of Del_1 values for photon energy can be measured through a spectral elliptic analyzer. Specifically, the photomask 200 is disposed in the spectral ellipse analyzer. Thereafter, an optical beam for incident light is disposed to form an incident angle of 64.5 degrees with respect to the photomask to be measured, and a spectroscopic detector for detecting and analyzing reflected light in consideration of the incident angle is disposed. After the arrangement of the optical band and the spectral detector is completed, the Del_1 value can be measured while changing the photon energy of the incident light within a certain range. In this case, it is possible to easily and accurately measure the optical properties of only the protective layer in the depth direction without physically separating the protective layer from the phase shift film. The Del_1 value may be measured by using the MG-PRO model manufactured by Nano-View.

When measuring the Del_1 value of the photomask 200 , the light blocking film 30 positioned on the phase shift film 10 is removed and then measured. When the photomask 20 further includes another layer between the phase shift layer 20 and the light blocking layer 30 , the other layer is also removed. That is, the photomask 200 is processed and measured so that the outermost surface of the phase shift film 20 is exposed. As a method of removing the light blocking film 30 and the other films, there is an etching method using an etchant.

Depending on the manufacturing process, an interface in which the phase shift film 20 in the photomask 200 and components of other layers positioned on the phase shift film 20 are mixed may exist. In this case, the Del_1 value of the photomask is measured after removing the interface.

When the etching method is applied as a method for removing the thin film located on the phase shift film 20 , it is technically difficult to remove the film located on the phase shift film 20 without damage to the phase shift film 20 , so after etching After processing so that the thickness of the protective layer of the phase shift film 20 is 1 nm or more, the Del_1 value of the photomask is measured.

In the semiconductor device manufacturing equipment 1000 _{, when the PE 1} value is 3.0 eV and the PE ₂ value is 5.0 eV, the photomask 200 has the photon energy of the incident light at the point where the Del_1 value expressed by Equation 1 is 0. 4.0 to 5.0 eV. In the photomask 200 , when the PE ₁ value is 3.0 eV and the PE ₂ value is 5.0 eV, the photon energy of the incident light at the point where the Del_1 value is 0 is 4.1 to 4.6 eV. In the photomask 200, when the PE ₁ value is 3.0 eV and the PE ₂ value is 5.0 eV, the photon energy of the incident light at the point where the Del_1 value expressed in Equation 1 is 0 is 4.3 to 4.5 eV. In this case, the photomask may have stable durability while having desired optical properties.

In the semiconductor device manufacturing equipment 1000 , when the photomask 200 has a PE ₁ value of 1.5 eV and a PE ₂ value is the minimum value among photon energies of incident light at a point where the Del_1 value expressed by Equation 1 becomes 0 , the average value of Del_1 expressed by Equation 1 is 85 to 100°/eV.

The inventors of the embodiment found that the phase difference (Δ) distribution between the P wave (P`) and the S wave (S`) _{of the reflected light (L r} ) in a range in which the photon energy value of the incident light is relatively low with respect to the phase shift film or the phase shift film pattern , that is, it was experimentally confirmed that the optical characteristics of the lower layer of the phase shift film (specifically, the phase difference adjusting layer) could be confirmed by measuring the distribution of the Del_1 value. In addition, the inventors of the embodiment experimentally confirmed that the phase shift film in which the Del_1 value measured by the above method is controlled within a certain range satisfies all preset optical properties for a light source of a short wavelength while having a relatively thin thickness.

The distribution of the Del_1 value in the range where the photon energy value of the incident light is relatively low can be controlled by adjusting various factors such as the elemental composition of the phase difference adjustment layer, the substrate rotation speed during sputtering, the magnetic field strength of the magnet, and the composition of the atmosphere gas in the chamber. have. In the embodiment, the Del_1 value in a range in which the photon energy value of the incident light is relatively low is controlled by adjusting the magnetic field strength applied when the phase difference adjusting layer 21 is formed.

When the phase difference adjustment layer 21 is formed using sputtering equipment, a magnet is placed in the sputtering equipment and a magnetic field is formed to distribute plasma over the entire surface of the target in the chamber. In addition, the distribution, strength, etc. of the magnetic field may affect the density of the film formed by sputtering equipment.

Specifically, the higher the magnetic field strength, the higher the density of plasma formed in the chamber, so that the deposited phase difference adjusting layer 21 may be dense. As the magnetic field strength is weaker, the density of plasma formed in the chamber may be lowered, and thus the deposited retardation adjusting layer 21 may be sparse. That is, by controlling the magnetic field conditions of the sputtering equipment, the degree of density of the phase difference adjustment layer 21 is adjusted, so that the PE ₁ value is 1.5 eV, the PE ₂ value is the Del_1 value, and the minimum value among the photon energy of the incident light at the point where the value is 0. You can control the value of Del_1 when

Specific process conditions for forming the phase shift film protective layer, the phase difference adjusting layer, and each layer are omitted because they overlap with the contents described below.

In the semiconductor device manufacturing equipment 1000 , the photomask 200 _{is Del_1 expressed by Equation 1 when the PE 1} value is 1.5 eV and the PE ₂ value is the minimum value among photon energies of the incident light at the point where the Del_1 value is 0. An average value of may be 85 to 100°/eV. The average value of Del_1 may be 89 to 98°/eV. The average value of Del_1 may be 91 to 96°/eV. In this case, the retardation adjusting layer 21 may be thinned while satisfying all of the complementary optical characteristic requirements.

In the semiconductor device manufacturing equipment 1000 , in the photomask 200 , when the PE ₁ value is 1.5 _{eV and the PE 2} value is 5.0 eV, the maximum value of Del_1 expressed by Equation 1 is 80 to 250°/eV .

The inventors of the embodiment have experimentally confirmed that there is a certain tendency between the maximum value of Del_1 of the phase shift film and the durability of the phase shift film. Specifically, it was confirmed that the higher the maximum value of Del_1 of the phase shift film, the lower the durability of the phase shift film, and the lower the maximum value of Del_1 of the phase shift film, the higher the durability of the phase shift film.

On the other hand, as the durability of the phase shift film increased, the degree of damage to the phase difference adjusting layer according to the exposure process and the cleaning process decreased. The inventors of the embodiment confirmed that the phase shift film can have the desired optical properties while exhibiting stable light resistance and chemical resistance by adjusting the maximum value of Del_1 of the phase shift film within a certain range, and completed the embodiment.

When the PE ₁ value is 1.5 _{eV and the PE 2} value is 5.0 eV, the maximum value of Del_1 is the content of each element in the thickness direction of the protective layer, the conditions for the pre/post treatment process of the heat treatment process, the applied temperature for each step during the heat treatment process, and the temperature It can be controlled by adjusting various factors such as the rate of rise, the composition and content of the atmosphere gas during the heat treatment process, and the thickness of the protective layer. In the embodiment, the maximum value of Del_1 by controlling the content of each element in the thickness direction of the protective layer by controlling the detailed process conditions of the UV light irradiation process for the retardation adjusting layer surface and the heat treatment process for forming the protective layer before forming the protective layer was controlled.

Specific process conditions for controlling the maximum value of Del_1 are omitted because they overlap with the description of the method for manufacturing the phase shift film described below.

In the semiconductor device manufacturing equipment 1000 , the maximum value of Del_1 is 80 to 250°/eV when the _{photomask 200 has a PE 1} value of 1.5 _{eV and a PE 2 value of 5.0 eV.} The maximum value of Del_1 is 130 to 220 eV. The maximum value of Del_1 is 150 to 200 eV. In this case, the phase shift film may have stable durability while reducing the influence of the optical properties of the protective layer itself on the optical properties of the entire phase shift film.

3 is a conceptual diagram illustrating a blank mask 100 manufactured according to another embodiment of the present specification. An embodiment will be described in detail below with reference to FIG. 3 .

The blank mask 100 according to another embodiment of the present specification includes a transparent substrate 10 , a phase shift film 20 disposed on the transparent substrate 10 , and a light blocking film ( 30) is included.

The material of the transparent substrate 10 is not limited as long as it has light transmittance to exposure light and can be applied to the photomask. For example, the transparent substrate 10 may be a synthetic quartz substrate.

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

The phase shift film 20 may include a phase difference adjustment layer 21 and a protective layer 22 positioned on the phase difference adjustment layer 21 .

The phase shift film 20 , the phase difference adjusting layer 21 , and the protective layer 22 may include a transition metal, silicon, oxygen, and nitrogen.

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

Specifically, the phase difference adjusting layer 21 has a characteristic of shifting the phase of the exposure light incident from the back side of the transparent substrate 10 . Due to these characteristics, the phase shift film 20 effectively cancels the diffracted light generated at the edge of the transmission part in the photomask, so that the resolution of the photomask is further improved during the lithography process.

In addition, the phase difference adjusting layer 21 attenuates exposure light incident on the surface of the phase shift film 20 . Through this, the phase shift film 20 may appropriately block the exposure light while canceling the diffracted light.

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

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

The light blocking film may have a single-layer structure. The light blocking film may have a multilayer structure of two or more layers. The light-shielding film may be formed through sputtering. The light blocking film may have a multilayer structure of two or more layers according to sputtering control conditions.

In the blank mask 100 , when the PE ₁ value is 3.0 eV and the PE ₂ value is 5.0 eV, the photon energy at the point where Del_2 expressed by Equation 2 below is 0 may be 4.0 to 5.0 eV.

[Equation 2]

In Equation 2 above,

The DPS value is, after removing the light blocking film from the blank mask, when the phase shift film surface is measured with a spectral ellipse analyzer by applying an incident angle of 64.5°, if the phase difference between the P wave and the S wave of the reflected light is 180° or less, the P It is the phase difference between the wave and the S wave, 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 .}

The technical meaning of the Del_2 value when the PE ₁ value is 3.0 eV and the PE ₂ value is 5.0 eV, the Del_2 value control method, and the Del_2 value measurement method, the PE ₁ value is 3.0 eV and the PE ₂ value is 5.0 eV Since it overlaps with the description of the Del_1 value at the time, it is omitted.

When measuring the Del_2 value of the blank mask 100 , it is measured after the light blocking film 30 positioned on the phase shift film 10 is removed. In detail, the description of how to remove the light-shielding film, etc. is omitted because it overlaps with the description described above when measuring the Del_1 value.

In the blank mask 100 , when the PE ₁ value is 3.0 eV and the PE ₂ value is 5.0 eV, the photon energy of the incident light at the point where Del_2 expressed in Equation 2 is 0 is 4.0 to 5.0 eV. In the blank mask 100 , when the PE ₁ value is 3.0 eV and the PE ₂ value is 5.0 eV, the photon energy of the incident light at the point where Del_2 expressed in Equation 2 is 0 is 4.1 to 4.6 eV. In the blank mask 100 , when the PE ₁ value is 3.0 eV and the PE ₂ value is 5.0 eV, the photon energy of the incident light at the point where Del_2 expressed in Equation 2 is 0 is 4.3 to 4.5 eV. In this case, the phase shift film 20 may have stable durability while suppressing fluctuations in optical properties of the phase shift film 20 due to the formation of the protective layer 22 .

In the blank mask 100 , when the PE ₁ value is 1.5 _{eV and the PE 2} value is 3.0 eV, the photon energy of the incident light at the point where Del_2 expressed in Equation 2 is 0 may be 1.7 to 2.3 eV.

As described above, the phase difference distribution between the P-wave and S-wave of the reflected light measured by setting the photon energy value of the incident light to a relatively low range reflects the optical characteristics of the layer located below the phase shift film. The distribution of Del_2 measured by setting the PE ₁ value to 1.5 _{eV and the PE 2} value to 3.0 eV shows the optical characteristics of the portion from the point adjacent to the transparent substrate side to the interface between the protective layer and the phase difference adjustment layer in the phase shift film, etc. indicates

In the blank mask 100 , when the PE ₁ value is 1.5 _{eV and the PE 2} value is 3.0 eV, the photon energy of the incident light at the point where Del_2 expressed in Equation 2 is 0 may be 1.7 to 2.3 eV. In the blank mask 100 , when the PE ₁ value is 1.5 _{eV and the PE 2} value is 3.0 eV, the photon energy of the incident light at the point where Del_2 expressed in Equation 2 is 0 may be 1.74 to 2.09 eV. In the blank mask 100 , when the PE ₁ value is 1.5 _{eV and the PE 2} value is 3.0 eV, the photon energy of the incident light at the point where Del_2 expressed in Equation 2 is 0 may be 1.8 to 2.05 eV. In this case, it is possible to provide the phase shift film 20 thinned while having a desired phase difference and transmittance for light of a short wavelength.

In the blank mask 100 , when the PE ₁ value is 1.5 eV and the PE ₂ value is the minimum value among the photon energies of the incident light at the point where the Del_2 value becomes 0, the photon energy of the incident light is the PE ₁ to the PE ₂ In the range, the average value of Del_2 may be 85 to 100°/eV.

The distribution of Del_2 measured by setting the PE ₁ value to 1.5 eV and the PE ₂ value as the minimum value among the photon energies of the incident light at the point where the Del_2 value becomes 0, specifically, the average value of the Del_2 is in the phase shift film 20 The optical characteristics of the phase difference adjusting layer 21, etc. are shown.

In the blank mask 100 , when the PE ₁ value is 1.5 eV and the PE ₂ value is the minimum value among photon energies of the incident light at the point where the Del_2 value becomes 0, the average value of Del_2 expressed by Equation 2 is 85 to 100° It can be /eV. In the blank mask 100 , when the PE ₁ value is 1.5 eV and the PE ₂ value is the minimum value among photon energies of the incident light at the point where the Del_2 value becomes 0, the average value of Del_2 expressed by Equation 2 is 86 to 95° It can be /eV. In the blank mask 100 , when the PE ₁ value is 1.5 eV and the PE ₂ value is the minimum value among photon energies of the incident light at the point where the Del_2 value becomes 0, the average value of Del_2 expressed by Equation 2 is 87 to 93° It can be /eV. In this case, the phase difference adjusting layer 21 may substantially contribute to the phase shift film 20 having a relatively low thickness and having a desired phase difference and transmittance for light having a short wavelength.

In the blank mask 100 , when the PE ₁ value is the minimum value among the photon energies of the incident light at the point where the Del_2 value becomes 0, and the PE ₂ value is the maximum value among the photon energies of the incident light at the point where the Del_2 value becomes 0, the incident light In the range of the photon energy of PE ₁ to PE ₂ , the average value of Del_2 may be -75 to -50°/eV.

The _{average value of Del_2 measured by setting the PE 1} value as the minimum value among photon energies of the incident light at the point where _{the Del_2 value becomes 0 and the PE 2} value as the maximum value among the photon energies of the incident light at the point where the Del_2 value becomes 0 is It substantially reflects the optical properties of the layer located near the interface between the phase difference adjusting layer 21 and the protective layer 22 .

In the blank mask 100, the PE ₁ value is the minimum value among photon energies of the incident light at the point where the Del_2 value becomes 0, and the PE ₂ value is the maximum value among the photon energies of the incident light at the point where the Del_2 value becomes 0. The average value of Del_2 expressed by Equation 2 may be -75 to -50°/eV. In the blank mask 100, the PE ₁ value is the minimum value among photon energies of the incident light at the point where the Del_2 value becomes 0, and the PE ₂ value is the maximum value among the photon energies of the incident light at the point where the Del_2 value becomes 0. The average value of Del_2 expressed by Equation 2 may be -60 to -52°/eV. In the blank mask 100, the PE ₁ value is the minimum value among photon energies of the incident light at the point where the Del_2 value becomes 0, and the PE ₂ value is the maximum value among the photon energies of the incident light at the point where the Del_2 value becomes 0. The average value of Del_2 expressed by Equation 2 may be -59 to -55°/eV. In this case, it is possible to suppress variations in the phase difference, transmittance, etc. of the phase shift film due to the formation of the interface between the phase difference adjusting layer 21 and the protective film 22 .

In the blank mask 100 , the PE ₁ value is the maximum value among the photon energies of the incident light at the point where the Del_2 value becomes 0, and when the PE ₂ value is 5.0 eV, the photon energy of the incident light is the PE ₁ to the PE _{In the} range of 2, the average value of Del_2 expressed by Equation 2 may be 40 to 120°/eV.

The PE ₁ value is the maximum value among photon energies of incident light at the point where the Del_2 value becomes 0, and _{the average value of Del_2 measured by setting the PE 2} value to 5.0 eV reflects the optical characteristics of the protective layer 22 .

In the blank mask 100 , the PE ₁ value is the maximum value among photon energies of the incident light at the point where the Del_2 value becomes 0 _{, and when the PE 2} value is 5.0 eV, the average value of Del_2 expressed by Equation 2 is 40 to 120 °/eV. In the blank mask 100 , the PE ₁ value is the maximum value among photon energies of the incident light at the point where the Del_2 value becomes 0 _{, and when the PE 2} value is 5.0 eV, the average value of Del_2 expressed by Equation 2 is 60 to 85 °/eV. In the blank mask 100 , the PE ₁ value is the maximum value among photon energies of the incident light at the point where the Del_2 value becomes 0 _{, and when the PE 2} value is 5.0 eV, the average value of Del_2 expressed by Equation 2 is 65 to 75 °/eV. In this case, the protective layer 22 can stably protect the phase difference adjusting layer 21 while reducing the influence of the optical properties of the protective layer 22 itself on the optical properties of the entire phase shift film 20 .

The blank mask 100 includes a phase shift film 20, and the phase shift film 20 includes a phase difference adjustment layer 21 and a protective layer 22 positioned on the phase difference adjustment layer 21, , in the blank mask 100, when the PE ₁ value is 1.5 _{eV and the PE 2} value is 3.0 eV, the value of the photon energy of the incident light at the point where the Del_2 value is 0 and before the protective layer 22 is formed When the PE ₁ value is 1.5 _{eV and the PE 2} value is 3.0 eV, the absolute value of the difference between photon energy values of the incident light at the point where the Del_2 value is 0 may be 0.001 to 0.2 eV.

The phase shift film 20 may be manufactured by forming the retardation adjusting layer 21 through a sputtering process and then forming the protective layer 22 on the retardation adjusting layer 21 . Since the retardation adjusting layer 21 functions to substantially control the optical properties of the entire phase shift film 20 , the retardation adjusting layer 21 may be formed by forming a film to exhibit previously designed optical properties. Thereafter, the protective layer 22 may be formed on the phase difference adjusting layer 21 by exposing it to an atmospheric gas under a high temperature and a constant pressure. However, in the process of forming the protective layer 22 , due to internal residual stress of the retardation adjusting layer 21 , a composition change of the surface of the retardation adjusting layer 21 , etc., optical properties of the retardation adjusting layer 21 itself may be changed. . When the optical property variation occurs beyond a certain range, the optical properties of the entire phase shift film 20 deviate from the pre-designed optical property requirements, and as a result, the optical properties of the photomask 200 deviate from the preset properties, so that the wafer It may cause a decrease in the resolution of the pattern being developed. The blank mask 100 of the embodiment controls the internal residual stress of the retardation adjusting layer 21 to be formed by adjusting the magnetic field strength of the sputtering chamber when the retardation adjusting layer 21 is formed, and UV light when forming the protective layer 22 By applying a heat treatment process in which irradiation and detailed temperature change conditions are controlled, the amount of change in the optical properties of the phase difference adjusting layer 21 itself compared to before and after the formation of the protective layer 22 is adjusted to provide a blank mask that meets all of the pre-designed optical properties requirements. can

The blank mask 100 includes a phase shift film 20, and the phase shift film 20 includes a phase difference adjustment layer 21 and a protective layer 22 positioned on the phase difference adjustment layer 21, , in the blank mask 100, when the PE ₁ value is 1.5 _{eV and the PE 2} value is 3.0 eV, the value of the photon energy of the incident light at the point where the Del_2 value is 0 and before the protective layer 22 is formed When the PE ₁ value is 1.5 _{eV and the PE 2} value is 3.0 eV, the absolute value of the difference between photon energy values of the incident light at the point where the Del_2 value is 0 may be 0.001 to 0.2 eV. The absolute value of the difference value may be 0.005 to 0.1 eV. The absolute value of the difference value may be 0.01 to 0.008 eV. In this case, the blank mask 100 can suppress the optical fluctuation of the phase difference adjustment layer 21 itself due to the formation of the protective layer 22, so that the optical property requirements such as retardation and transmittance required for a short wavelength can be satisfied. .

The blank mask 100 includes a phase shift film 20, and the phase shift film 20 includes a phase difference adjustment layer 21 and a protective layer 22 positioned on the phase difference adjustment layer 21, , in the blank mask 100 , when the PE ₁ value is 3.0 eV and the PE ₂ value is 5.0 eV, the value of the photon energy of the incident light at the point where the Del_2 value is 0 and before the protective layer 22 is formed When the PE ₁ value is 3.0 eV and the PE ₂ value is 5.0 eV, the absolute value of the difference between photon energy values of the incident light at the point where the Del_2 value is 0 may be 0.05 to 0.3 eV.

In the blank mask 100 of the embodiment, after the phase difference adjusting layer 21 is formed, the protective layer 22 may be formed through a UV light irradiation process and a heat treatment process. Due to the formation of the protective layer 22 , the overall thickness of the phase shift film 20 may be increased compared to before formation, and optical properties of the entire phase shift film 20 may be varied within a certain range. This may be a factor in forming a difference in the Del_2 value distribution in a range in which the photon energy of the blank mask 100 is relatively high before and after the formation of the protective layer 22 . The inventors of the embodiment found that the photon energy of incident light at the point where the Del_2 value is 0 when the _{PE 1} value of the phase shift film 20 is 3.0 eV and the PE ₂ value is 5.0 eV before and after the formation of the protective layer 22 . It was confirmed that durability and optical properties of the phase shift film 20 can be adjusted by adjusting the difference value of .

The blank mask 100 includes a phase shift film 20, and the phase shift film 20 includes a phase difference adjustment layer 21 and a protective layer 22 positioned on the phase difference adjustment layer 21, , in the blank mask 100, when the PE ₁ value is 1.5 _{eV and the PE 2} value is 3.0 eV, the value of the photon energy of the incident light at the point where the Del_2 value is 0 and before the protective layer 22 is formed When the PE ₁ value is 1.5 _{eV and the PE 2} value is 3.0 eV, the absolute value of the difference between the photon energy values of the incident light at the point where the Del_2 value is 0 may be 0.05 to 0.3 eV. The absolute value of the difference value may be 0.06 to 0.25 eV. The absolute value of the difference value may be 0.1 to 0.23 eV. In this case, in the blank mask 100 , optical properties and durability of the protective layer 22 may be adjusted.

In the blank mask 100 , when the PE ₁ value is 1.5 _{eV and the PE 2} value is 5.0 eV, the maximum value of Del_2 expressed by Equation 2 is 80 to 250°/eV.

Similar to the description of the durability of the phase shift film in the photomask 200 and the tendency between the maximum value of Del_1, the inventors of the embodiment disclosed that the blank mask 100 also has a PE ₁ value of 1.5 eV, and a PE ₂ value of 5.0 eV. , it was experimentally confirmed that by controlling the maximum value of Del_2 expressed by Equation 2, the phase shift film had stable durability and the phase difference and transmittance fluctuations of the entire phase shift film due to the formation of the protective layer could be controlled within a certain range. .

The method of adjusting the maximum value of Del_2 and the method of measuring the maximum value of Del_2 are omitted because they overlap with those described above.

In the blank mask 100 , when the PE ₁ value is 1.5 _{eV and the PE 2} value is 5.0 eV, the maximum value of Del_2 is 80 to 250°/eV. The maximum value of Del_2 is 130 to 220 eV. The maximum value of Del_2 is 150 to 200 eV. In this case, the phase shift film may have excellent light resistance and chemical resistance, etc. while reducing the fluctuation of optical properties of the entire phase shift film due to the formation of the protective layer.

In the blank mask 100 , the photon energy at the point where Del_2 is the maximum value may be 4.5 eV or more.

As described above, as the photon energy of the incident light is higher, the measured value of the phase difference between the P and S waves of the reflected light reflects the optical characteristics of the shallow layer from the outermost surface of the phase shift film 20, and the photon energy of the incident light is lower. The measured values of the phase difference between the P-wave and S-wave of the reflected light reflect the optical characteristics of the deep layer from the outermost surface of the phase shift film 20 .

When the _{value of PE 1} is 1.5 eV and the value of PE ₂ is 5.0 eV, the maximum value of Del_2 reflects the characteristic shown in the protective layer 22 of the embodiment. Therefore, by adjusting the photon energy value at the maximum value of Del_2, the protective layer 22 exhibits stable protective properties with respect to the phase difference adjusting layer 21 and the effect on the optical properties of the entire phase shift film 20 is reduced. can be reduced

In the blank mask 100 , when the PE ₁ value is 1.5 _{eV and the PE 2} value is 5.0 eV, the photon energy value at the maximum value of Del_2 may be 4.5 eV or more. The photon energy value at the point that is the maximum value of Del_2 may be 4.55 eV or more. The photon energy value at the point where the Del_2 is the maximum value may be 5 eV or less. The photon energy value at the point that is the maximum value of Del_2 may be 4.8 eV or less. In this case, the phase shift film 20 can exhibit desired optical properties with respect to a short wavelength, and at the same time suppress optical properties fluctuations due to exposure and cleaning processes.

In the blank mask 100 , when the PE ₁ value is 1.5 _{eV and the PE 2} value is 5.0 eV, a value obtained by subtracting the minimum value of Del_2 from the maximum value of Del_2 may be 60 to 260 eV.

According to the present inventors, when the PE ₁ value is 1.5 _{eV and the PE 2} value is 5.0 eV, the maximum value of Del_2 reflects the optical characteristics of the protective layer 22 of the phase shift film 20 and the like, and the Del_2 It was confirmed experimentally that the minimum value of the phase difference adjustment layer 21 reflects the optical characteristics of the upper part.

_{When the PE 1} value is 1.5 _{eV and the PE 2} value is 5.0 eV before and after the formation of the passivation layer, the maximum value of Del_2 and the minimum value of Del_2 may vary. When the value obtained by subtracting the minimum value of Del_2 from the maximum value of Del_2 is controlled within a predetermined range, optical characteristics variation of the entire phase shift film 20 before and after formation of the protective layer 22 may occur within an allowable range.

In the blank mask, when the PE ₁ value is 1.5 _{eV and the PE 2} value is 5.0 eV, a value obtained by subtracting the minimum value of Del_2 from the maximum value of Del_2 may be 60 to 260 eV. A value obtained by subtracting the minimum value of Del_2 from the maximum value of Del_2 may be 80 to 240 eV. A value obtained by subtracting the minimum value of Del_2 from the maximum value of Del_2 may be 90 to 230 eV. In this case, the optical characteristic variation of the entire phase shift film before and after formation of the protective layer may be controlled within a certain range.

Composition of phase shift film

The phase shift 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. Exemplarily, the transition metal may be molybdenum.

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

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

The phase shift film 20 may have different content for each element in the thickness direction.

The content distribution for each element formed in the depth direction of the phase difference adjusting layer 21 and the protective layer 22 may be confirmed by measuring a depth profile of the phase shift film. For example, the depth profile may be measured using the K-alpha model of Thermo Scientific.

The phase difference adjusting layer 21 and the protective layer 22 may have different content of each element such as a transition metal, silicon, oxygen, and nitrogen for each layer.

The phase difference adjusting layer 21 may contain 3 to 10 atomic % of a transition metal. The phase difference adjusting layer 21 may contain 4 to 8 atomic % of the transition metal. The phase difference adjusting layer 21 may contain 20 to 50 atomic % of silicon. The phase difference adjusting layer 21 may contain 30 to 40 atomic % of silicon. The phase difference adjusting layer 21 may contain 2 to 12 atomic % oxygen. The phase difference adjusting layer 21 may contain 3 to 10 atomic % oxygen. The phase difference adjusting layer 21 may contain 40 to 60 atomic % nitrogen. The phase difference adjusting layer 21 may contain 45 to 55 atomic % nitrogen. In this case, it is possible to provide a blank mask having excellent pattern resolution when short-wavelength exposure light, specifically, light having a wavelength of 200 nm or less is applied as exposure light when manufacturing a photomask.

As the protective layer 22 contains more oxygen, the phase difference adjusting layer 21 can be stably protected from exposure light and a cleaning solution, but the degree of variation in optical properties of the entire phase shift film 20 may increase. Accordingly, by controlling the content distribution of oxygen and nitrogen in the protective layer 22 , the phase shift film 20 may have sufficient light resistance and chemical resistance while having desired optical properties.

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

The protective layer 22 may include a region in which the nitrogen content (atomic %) 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, it is possible to effectively suppress fluctuations in the optical properties of the phase shift film 20 due to the formation of the protective layer 22 .

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 30 to 80 compared to the total thickness of the protective layer 22 . % thickness. The region may have a thickness of 40 to 60% of the total thickness of the protective layer 22 . In this case, it is possible to provide a blank mask capable of manufacturing a photomask having excellent resolution while having sufficient long-term durability.

The content distribution for each element of the phase shift film 20 , the phase difference adjusting layer 21 , and the protective layer 22 and the content distribution for each element formed in the thickness direction can be confirmed by measuring the depth profile. For example, it can be measured through the K-alpha model of Thermo Scientific.

The thickness measurement of the region in which the ratio of the nitrogen content (atomic %) to the oxygen content (atomic %) in the thickness direction is 1 or more may be confirmed by measuring the 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 thickness measurement of the region in which the ratio of the nitrogen content (atomic %) to the oxygen content (atomic %) in the thickness direction is 0.4 to 2 may be confirmed by measuring the depth profile. However, it is assumed that the etching rate for each depth of the protective layer 22 is constant in the depth profile.

Optical properties of phase shift film

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

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

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

The retardation adjusting layer 21 may have a refractive index of 2 to 4 for light having a wavelength of 200 nm or less. The retardation adjusting layer 21 may have a refractive index of 2 to 4 for ArF light. The refractive index of the retardation adjusting layer 21 with respect to light having a wavelength of 200 nm or less may be 2.5 to 3.5. The refractive index of the retardation adjusting layer 21 with respect to ArF light may be 2.5 to 3.5. An extinction coefficient for light having a wavelength of 200 nm or less of the phase difference adjusting layer 21 may be 0.3 to 0.7. The extinction coefficient for ArF light of the phase difference adjusting layer 21 may be 0.3 to 0.7. An extinction coefficient for light having a wavelength of 200 nm or less of the phase difference adjusting layer 21 may be 0.4 to 0.6. The extinction coefficient for ArF light of the phase difference adjusting layer 21 may be 0.4 to 0.6. In this case, the photomask including the phase shift film 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 film 20, the protective layer 22 and the phase difference adjustment layer 21 included in the phase shift film 20 can be measured through NANO-VIEW's MG-PRO equipment. can

Thickness of each layer of phase shift film

A ratio of the thickness of the protective layer 22 to the thickness of the phase shift film 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 may stably protect the phase difference adjusting layer 21 .

The thickness of the passivation layer 22 may be 25 Å or more and 80 Å or less. The thickness of the passivation layer 22 may be 35 Å or more and 45 Å or less. In this case, it is possible to provide the phase shift film 20 that effectively controls the degree of change in optical properties on the entire phase shift film and exhibits stable optical properties despite a number of exposure and cleaning processes.

For example, the phase shift film 20 and the thickness of each layer constituting the phase shift film 20 may be confirmed through a TEM image of a cross section of the phase shift film 20 .

Manufacturing method of phase shift film

Among the phase shift film 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 DC power or RF power.

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

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

In the case of the sputtering gas, the sputtering gas may be prepared in consideration of a composition other than the composition contained in the target among the 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 the gas containing the elements constituting the thin film. Examples of the inert gas include Ar, He, and the like, but are not limited thereto. The film quality of a thin film formed during sputtering may be changed according to the composition of the inert gas. 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 gases of each composition.

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

As described above, when the magnetic field of the magnet is adjusted, the density of plasma formed in the chamber is adjusted to control the TFT value of the blank mask 100 and the optical characteristics of the phase shift film 20 to be formed. 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 film 20 to be formed may exhibit excellent resolution by suppressing thermal fluctuations in the thickness direction in a lithography process to which exposure light of a short wavelength 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-forming 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, it is possible to suppress an excessive increase in the internal stress of the thin film to be formed.

In the sputtering process, the rotation speed of the substrate to be formed may be adjusted. The rotation speed of the substrate to be formed may be 2 to 20 RPM. The rotation speed of the substrate may be 5 to 15 RPM. When the rotation speed of the substrate to be formed is adjusted within this range, the phase shift film 20 formed into a film may have stable durability while the degree of equalization of optical properties in the in-plane direction is further improved.

In addition, it is possible to adjust the intensity of the voltage applied to the sputtering target when the phase difference control layer 21 is formed. 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 controlling the intensity of the voltage, it is possible to control the plasma atmosphere in the chamber 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 strength of the voltage may be 1.5 to 2.5 kW. The strength of the voltage may be 1.8 to 2.2 kW. In this case, the internal residual stress of the phase shift film 20 may be adjusted within a desired range.

A spectral ellipse analyzer can be installed in the sputtering equipment. Through this, the deposition time may be controlled so that the phase difference adjusting layer 21 to be formed may have desired optical properties. Specifically, after setting the angle (θ) the incident light (L _i ) forms with the surface of the retardation adjusting layer 21 formed into a film, the Del_2 value of the retardation adjusting layer 21 formed in real time during the deposition process can be monitored. have. By performing the deposition process until the Del_2 value falls within a set range, the phase shift film 20 may have desired optical properties.

Immediately after the sputtering process is completed, the surface of the retardation control layer 21 may be irradiated with a UV light source. _{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 can form a mixture with The mixture may be in a homogeneous state or in an inhomogeneous state. In the case of the phase difference control layer 21 having a non-uniform mixture formed on the surface, a haze defect may be formed on the surface of the phase difference control layer 21 by exposure light of a short wavelength during an exposure process. In addition, when sulfuric acid is used as a cleaning liquid in the 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 a non-uniform mixture when receiving strong energy from exposure light during the wafer exposure process for a long period of time to generate growth defects on the surface of the phase difference control layer 21 . Therefore, by exposing UV light of a preset wavelength to the surface of the phase difference control layer 21 to equalize the transition metal and N content in the mixture of the surface of the phase difference control layer 21 in the direction of the film, the light resistance and resistance of the phase difference control layer 21 It can improve drug properties.

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

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

The phase difference control layer 21 after the deposition through the sputtering process may have an internal stress. The internal stress may be a compressive stress or a tensile stress depending on the conditions of sputtering. The internal stress of the phase difference control layer 21 may cause warpage of the substrate, which may cause a decrease in resolution of a photomask manufactured using the blank mask 100 . When heat treatment is performed on the phase difference control layer 21 , the internal stress of the phase shift film 20 is reduced to reduce warpage of the substrate.

The protective layer 22 may be formed on the phase difference adjusting 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 adjusting layer 21 through sputtering. During the heat treatment process, the protective layer 22 may be formed by reacting the surface of the phase difference adjusting layer 21 with the atmospheric gas.

The protective layer 22 may be formed on the surface of the retardation control layer 21 by introducing an atmospheric gas in the chamber during the heat treatment process. Atmospheric gas may be introduced during the heat treatment process. The atmospheric gas includes He, Ar, and the like, but is not limited thereto.

The heat treatment process may include a temperature raising step, a temperature maintaining step, a temperature decreasing step, and a protective layer forming step. The heat treatment process may be performed by disposing a blank mask having the phase difference control layer 21 formed thereon in a chamber and then heating it through 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 maintenance step may be performed for 5 to 60 minutes. The temperature lowering step is a step of lowering the temperature in the chamber from the set temperature to room temperature. The protective layer forming step is a step of forming a protective layer on the surface of the phase shift film by introducing a gas containing a reactive gas into the chamber after the temperature lowering step is completed. The reactive gas may include _{O 2 .} The gas introduced into the chamber in the protective layer forming step _{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 to 60 minutes. The protective layer forming step may proceed for 12 to 45 minutes. In this case, the content of each element in the thickness direction of the passivation layer 22 may be adjusted to suppress fluctuations in optical properties of the phase shift film 20 due to the passivation layer 22 .

Light-shielding film manufacturing method, composition and optical properties

The light blocking film 30 may have a single-layer structure. The light blocking film 30 may have a multi-layer structure of two or more layers. The light blocking film 30 may be formed through sputtering. The light blocking film 30 may have a layer structure of two or more layers according to sputtering control conditions. Light-shielding film 30 During the sputtering process, a plurality of light-shielding films 30 may be formed by changing the flow rate for each atmospheric gas for each layer. Light-shielding film 30 During the sputtering process, a plurality of light-shielding films 30 may be formed by changing the sputtering target for each layer.

The light blocking layer 30 may include chromium, oxygen, nitrogen, and carbon. The content of each element relative to the entire light blocking layer 30 may be different in the thickness direction. The content of each element relative to the total light blocking film 30 may be different for each layer in the case of the plurality of layers of the light blocking film 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 film 30 may contain 5 to 30 atomic % carbon. The light blocking film 30 may contain 7 to 25 atomic % carbon. The light blocking layer 30 may contain 3 to 20 atomic % nitrogen. The light blocking layer 30 may contain 5 to 15 atomic % nitrogen. The light blocking layer 30 may contain 20 to 45 atomic % oxygen. The light blocking layer 30 may contain 25 to 40 atomic % oxygen. In this case, the light blocking film 30 may have sufficient quenching characteristics.

The phase shift film 20 and the light blocking film 30 are included in the multilayer. The multilayer may form a blind pattern on the transparent substrate 10 to suppress transmission of the exposure light.

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

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

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

The sputtering process may use DC power or RF power.

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

In the case of a sputtering target, one target containing chromium may be applied, and two or more targets including one target containing chromium may be applied. The target containing chromium may contain 90 atomic% or more of chromium. The target containing chromium may contain 95 atomic% or more of chromium. The target containing chromium may contain 99 atomic% or more of 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 film, the quality of the light-shielding film, optical characteristics, and the like.

The sputtering gas may include a reactive gas and an inert gas. By controlling the content of the reactive gas in the sputtering gas, it is possible to control the optical properties and film quality of the light-shielding film 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 controlling the content of the inert gas in the sputtering gas, it is possible to control the film quality of the light-shielding film formed into a film. The inert gas may include Ar, He, 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 including Ar, N2, He, and CO2 may be injected into the chamber. Specifically, the sputtering gas in which the sum of the flow rates of CO2 and N2 is 40% or more with respect to the total flow rate of the sputtering gas may be injected into the chamber. In this case, the light-shielding film lower layer may have a desired optical characteristic, and may contribute to the light-shielding film having a desired TFT2 value.

When forming the upper layer of the light blocking layer, a sputtering gas containing Ar and N2 may be injected into the chamber. Specifically, a sputtering gas having a flow rate of N2 of 30% or more relative to the total flow rate of the sputtering gas may be injected into the chamber. In this case, it can contribute to controlling the numerical fluctuation in the thickness direction according to the temperature of the light-shielding film.

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

A magnet may be disposed in the chamber to control the film quality of the light blocking film to be formed and the uniformity of in-plane optical properties. Specifically, by positioning the magnet on the back side of the sputtering target, and rotating the magnet at a speed of a certain size, plasma can be maintained at a constant distribution on the front surface of the target. The magnet may be rotated at a speed of 50 to 200 rpm when forming a film 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-shielding film, the T/S distance may be 240 to 300 mm. In this case, the film-forming 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, it is possible to suppress an excessive increase in the internal stress of the thin film to be formed.

In the sputtering process, the rotation speed of the substrate to be formed may be adjusted. When the light-shielding film is formed for each layer, the rotation 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 rotation speed of the substrate to be formed is adjusted within this range, the optical properties and TFT2 values of each layer of the formed light-shielding film 30 in the in-plane direction can be further increased, and the durability of the light-shielding film 30 is improved. can be

In addition, it is possible to adjust the intensity of the voltage applied to the sputtering target when the light blocking film 30 is formed. 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 controlling the intensity of the voltage, it is possible to control the plasma atmosphere in the chamber 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 light-shielding layer underlayer is formed may be 0.5 to 2 kW. The strength of the voltage may be 1.0 to 1.8 kW. The strength of the voltage may be 1.2 to 1.5 kW. The strength of the voltage applied to the sputtering target during the formation of the upper layer of the light blocking layer may be 1 to 3 kW. The strength of the voltage may be 1.3 to 2.5 kW. The strength of the voltage may be 1.5 to 2.0 kW. In this case, it is possible to suppress excessive numerical fluctuations in the thickness direction of the light blocking film 30 according to the temperature.

A spectral ellipse analyzer can be installed in the sputtering equipment. Through this, the film formation time can be controlled so that the light blocking film 30 to be formed can have desired optical properties. The method of measuring after installing a spectral elliptic analyzer in the sputtering equipment when forming the light blocking film 30 is the same as in forming the phase shift film, so it is omitted.

When forming the lower layer of the light shielding film 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 a spectral elliptic analyzer is 140° becomes 1.6 to 2.2 eV. When forming the lower layer of the light shielding film 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 a spectral elliptic analyzer is 140° becomes 1.8 to 2.0 eV.

When the upper layer of the light blocking film 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 a spectral elliptic analyzer is 140° becomes 1.7 to 3.2 eV. When the upper layer of the light blocking film 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 a spectral elliptic analyzer is 140° becomes 2.5 to 3.0 eV.

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

A photomask according to another exemplary embodiment may be manufactured using the blank mask 100 described above.

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

A pattern can be formed by drawing a pattern on the resist film through EB or light irradiation, then heating and developing. 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 film 30 . The thin film to be etched may be another thin film formed on the light blocking film 30 . In the etching process, dry etching may be applied depending on the composition of the film to be etched. A chlorine-based gas and a fluorine-based gas may be applied as the etching gas applied to the dry etching.

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

4 is a graph of measuring the DPS value described in Equation 2 with respect to the photon energy of Examples 1 to 3, and FIG. 5 is a graph of measuring the Del_2 value of Equation 2 with respect to the photon energy of Examples 1 to 3, FIG. 6 is a graph of measuring the DPS value described in Equation 2 with respect to the photon energy of Comparative Examples 1 and 2, and FIG. 7 is a graph of measuring the Del_2 value of Equation 2 with respect to the photon energy of Comparative Examples 1 and 2. A specific embodiment will be described with reference to FIGS. 4 to 7 .

Hereinafter, specific examples will be described in more detail.

Preparation Example: Formation of phase shift film

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

After that, _{a sputtering gas mixed at a ratio of Ar:N 2} :He=9:52:39 was introduced into the chamber, the sputtering voltage was 2kW, and the magnet was rotated at a speed of 150rpm to perform a sputtering process. The area in which the thin film is formed was limited to the area set by the width of 132 mm and the width of 132 mm on the surface of the transparent substrate. The sputtering process was performed until the photon energy at the point where the Del_2 value according to Equation 2 was 0 became 2.0 eV.

After sputtering, the surface of the phase shift film of the blank mask was exposed to Excimer UV light with a wavelength of 172 nm at ^{7 mW/cm 2 power for 5 minutes.}

After that, the blank mask was introduced into a chamber for a heat treatment process, annealed at 1 Pa at 400° C. for 30 minutes, and then cooled naturally. _{After natural cooling, O 2} gas in the chamber for the 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 ℃.

A light-shielding film sputtering process was performed on the surface of the phase shift film formed into a film. Specifically, after the transparent substrate on which the phase shift film is formed and the chromium target are placed in the sputtering chamber, a sputter gas having a flow ratio of Ar:N ₂ :He:CO ₂ =19:11:34:37 is introduced into the chamber, and the sputtering voltage is applied. Sputtering was performed by applying 1.35kW. Sputtering was carried out until the photon energy at the point where the phase difference between the P wave and the S wave measured with a spectral elliptic analyzer was 140° reached 1.9 eV, thereby forming a light-shielding film lower layer.

Thereafter, sputtering gas having a flow ratio of Ar:N ₂ =57:43 was introduced into the chamber and sputtering was performed by applying a sputtering voltage of 2.75kW. Sputtering was carried out until the photon energy at the point where the phase difference between the P wave and the S wave measured with a spectral elliptic analyzer was 140° reached 2.75 eV, thereby forming an upper layer of the light-shielding film.

A total of two samples were prepared by applying the film-forming conditions as described above.

Example 2: The sputtering process was performed under the same conditions as in Example 1, but the magnet magnetic force was applied as 45 mT, and the process progress time was adjusted to the Del_2 value according to Equation 2 when the photon energy at the point of 0 is 1.89 eV was carried out until

Example 3: The sputtering process was performed under the same conditions as in Example 1, except that the composition of the sputtering gas _{was changed to a ratio of Ar:N 2} :He=8:58:34.

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

After that, _{a sputtering gas mixed at a ratio of Ar:N 2} :He=9:52:39 was introduced into the chamber, and the sputtering process was performed while rotating the magnet at a speed of 2kW and 100rpm at a sputtering voltage. The area in which the thin film is formed was limited to the area set by the width of 132 mm and the width of 132 mm on the surface of the transparent substrate. The sputtering process was performed until the photon energy at the point where the Del_2 value according to Equation 2 was 0 became 2.0 eV. No additional UV light treatment and heat treatment were applied.

A light-shielding film sputtering process was performed on the surface of the phase shift film formed into a film. Specifically, after the transparent substrate on which the phase shift film is formed and the chromium target are placed in the sputtering chamber, a sputter gas having a flow ratio of Ar:N ₂ :He:CO ₂ =19:11:34:37 is introduced into the chamber, and the sputtering voltage is applied. Sputtering was performed by applying 1.35kW. Sputtering was carried out until the photon energy at the point where the phase difference between the P wave and the S wave measured with a spectral elliptic analyzer was 140° reached 1.9 eV, thereby forming a light-shielding film lower layer.

Thereafter, sputtering gas having a flow ratio of Ar:N ₂ =57:43 was introduced into the chamber and sputtering was performed by applying a sputtering voltage of 2.75kW. Sputtering was carried out until the photon energy at the point where the phase difference between the P wave and the S wave measured with a spectral elliptic analyzer reached 140° became 2.75 eV, thereby forming a light-shielding film lower layer.

Comparative Example 2: A sputtering process was performed under the same conditions as in Comparative Example 1, but a magnet magnetic force of 20 mT was applied, and the composition of the sputtering gas _{was changed to a ratio of Ar:N 2} :He=8:58:34.

Evaluation example: Del_2 value measurement

The light-shielding film was removed through etching in the samples of Examples and Comparative Examples. Specifically, after each sample was placed in the chamber, an etching process was performed by supplying a chlorine-based gas as an etchant to remove the light blocking film.

Thereafter, the Del_2 value distribution was measured when _{PE 1} was 1.5 _{eV and PE 2} was 5.0 eV using a spectral elliptic analyzer (manufactured by MG-PRO, Nano-View) installed in a sputtering apparatus for each specimen in Examples and Comparative Examples. . Specifically, after setting the angle of incident light to 64.5 with respect to the surface of the phase shift film on which the film formation has been completed for each Example and Comparative Example, the phase difference between P and S waves according to photon energy was measured and converted into a Del_2 value. The parameters related to the Del_2 value distribution measured in Examples and Comparative Examples are shown in Table 1 below. Graphs showing the distribution of DPS values and Del_2 values measured for each Example and Comparative Example are described in FIGS. 4 to 7 .

Evaluation example: phase difference, transmittance measurement

With respect to the specimens of Examples and Comparative Examples described through Preparation Examples above, the light-shielding film was removed by etching in the same manner as when measuring the Del_2 value. The phase difference and transmittance were measured using a retardation/transmittance measuring instrument (MPM193 manufactured by Lasertec). Specifically, by using an ArF light source (wavelength 193 nm) to irradiate light to the region where the phase shift film is formed and the region where the phase shift film is not formed, the phase difference and transmittance difference values between the light passing through both regions are calculated. Therefore, it is described in Table 2 below.

Evaluation Example: Contrast and CD value measurement

After forming a photoresist film on the surface of the phase shift film of each specimen in Examples and Comparative Examples, a dense rectangular 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). After developing a pattern on the photoresist film of each specimen, the light blocking film and the phase shift film were etched according to the developed pattern shape using the Tetra X model of Applied Materials. Thereafter, the photoresist pattern was removed.

The contrast and normalized CD values of the developed patterns during the exposure process were measured and calculated using the AIMS 32 model manufactured by Carl Zeiss for the specimens for each Example and Comparative Example including the phase shift film pattern. For 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 shown in Table 2 below.

Evaluation Example: Measurement of the composition of each element in the thickness direction of the protective layer

For the specimens of Examples and Comparative Examples described through Preparation Examples above, the content of each element in the thickness direction of the protective layer was measured. Specifically, using Thermo Scientific's K-alpha model, analyzer type/channel: 180 degree double focusing hemispherical analyzer/120 channel, Al Ka micro-focused X-ray light source, 1 keV power, 1E-7 mbar working pressure, The content of each element in the thickness direction of the protective layer was measured by applying a gas as Ar.

When the protective layer according to Examples and Comparative Examples includes a region in which the ratio of nitrogen content to oxygen content is 0.4 to 2 in the thickness direction, and the region has a thickness of 30 to 80% of the total thickness of the protective layer, O, the region is When it had a thickness of less than 30% or more than 80% of the total thickness of the protective layer, it was evaluated as X. The measured data are shown in Table 2 below.

magnetic field (mT) At PE ₁ 1.5 eV, PE ₂ 3 eV
Photon energy (eV) at the point where Del_2 value is 0 PE ₁ 3eV, PE ₂ 5eV
Photon energy (eV) at the point where Del_2 value is 0 At PE ₁ 1.5 eV, PE ₂ S*
Average value of Del_2 (°/eV) For PE ₁ S*, PE ₂ B*
Average value of Del_2 (°/eV) At PE ₁ B*, PE ₂ 5eV
Average value of Del_2 (°/eV) At PE ₁ 1.5 eV, PE ₂ 5 eV
Maximum value of Del_2 (°/eV) Example 1 40 2.00 4.44 86.61 -58.73 70.12 192.40 Example 2 45 1.88 4.31 91.77 -57.53 73.78 212.52 Example 3 35 2.09 4.65 92.67 -55.72 66.00 161.22 Comparative Example 1 60 1.73 3.84 88.42 -66.82 85.62 350.32 Comparative Example 2 20 2.10 4.80 87.50 -56.58 58.11 126.21

* S* means the minimum value among photon energies of incident light at the point where the Del_2 value becomes 0.

* B* means the maximum value among photon energies of incident light at the point where the Del_2 value becomes 0.

Transmittance (%) Phase difference (°) Evaluation of the composition of each element in the thickness direction of the protective layer Normalized Contrast Normalized CD (nm) Example 1 6.1 178.5 O 1.000 0.99 Example 2 5.4 186.1 O 0.989 1.01 Example 3 6.9 172.4 O 0.959 1.03 Comparative Example 1 3.4 209.1 X 0.929 1.06 Comparative Example 2 7.8 166.0 X 0.883 1.10

In Table 1, Examples 1 to 3 in which the magnetic field was applied within the range of 30 to 50 mT, it can be confirmed that the Del_2 related parameter value was adjusted within the desired range in the embodiment, but Comparative Example 1 in which the magnetic field was applied to less than 30 mT or more than 50 mT and 2 can confirm that one or more parameters are outside the desired range in the embodiment. Through this, it can be seen that the distribution of the Del_2 value according to the photon energy of the phase shift film can be controlled by adjusting the magnetic force of the magnet in the sputtering process.

In Table 2, 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. and Comparative Example 2 was measured to have a transmittance of 7.5% or more and a phase difference of less than 170°. Through this, it can be seen that the phase shift film with the Del_2 value distribution adjusted exhibits optical characteristics close to the desired transmittance (6%) and phase difference (180 degrees) for exposure light with a short wavelength.

In Table 2, in Examples 1 to 3, the region in which the ratio of nitrogen content to oxygen content in the protective layer in the thickness direction is 0.4 to 2 has a thickness of 30 to 80% of the total thickness of the protective layer, whereas Comparative Examples 1 and 2, it can be seen that the region has a thickness of less than 30% or more than 80% of the total thickness of the protective layer.

In Table 2, Examples 1 to 3 showed a normalized contrast of 0.95 or more and a normalized CD value of 1.03 or less, whereas Comparative Examples 1 and 2 showed a normalized contrast of less than 0.93, and the normalized CD value was 1.06 or higher. Through this, it can be seen that the phase shift film with the Del_2 value distribution adjusted has a higher level of resolution during exposure.

Although the preferred embodiment has been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the embodiment defined in the following claims are also within the scope of the present invention. will belong

100: blank mask
10: transparent substrate
20: phase shift film 21: phase difference adjusting layer 22: protective layer
30: light shield
200: photo mask
300: light source
400: lens
500: semiconductor wafer
1000: semiconductor device manufacturing device
θ: angle of incidence N: normal
L _i : incident light L _r : reflected light
P: P-wave component of incident light S: S-wave component of incident light
P`: P wave component of reflected light S`: S wave component of reflected light
△: phase difference between P wave and S wave of reflected light

Claims (12)

delete transparent substrate;
a phase shift film disposed on the transparent substrate; and
a light blocking film disposed on the phase shift film;
The phase shift film contains 2 to 7 atomic % of a transition metal and 25 to 50 atomic % of silicon,
When the PE ₁ value is 1.5 _{eV and the PE 2} value is 5.0 eV, the maximum value of Del_2 expressed by Equation 2 below is 130 to 220 °/eV,
The phase shift film includes a phase difference adjustment layer and a protective layer located on the phase difference adjustment layer,
The phase shift film further comprises oxygen and nitrogen,
The phase difference adjusting layer contains 40 to 60 atomic % of nitrogen,
The protective layer contains 20 to 40 atomic % of nitrogen,
The protective layer includes a region in which the ratio of nitrogen content to oxygen content is 0.4 to 2 in a thickness direction, and the region has a thickness of 30 to 80% with respect to the total thickness of the protective layer,
The thickness ratio of the protective layer to the thickness of the phase shift film is 0.04 to 0.09,
The passivation layer has an extinction coefficient of 0.2 to 0.4 for ArF light,
The light-shielding film may include a blank mask including chromium, oxygen, nitrogen and carbon;
[Equation 2]

In Equation 2 above,
The DPS value is, when the light blocking film is removed from the blank mask and the surface of the phase shift film is measured with a spectral ellipse analyzer by applying an incident angle of 64.5°, if the phase difference between the P wave and the S wave of the reflected light is 180° or less, the P is the phase difference between the wave and the S wave, 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 the photon energy of the incident light within the range of _{PE 1} to PE _{2 .}
3. The method of claim 2,
When the PE ₁ value is the minimum value among the photon energies of the incident light at the point where the Del_2 value becomes 0, and the PE ₂ value is the maximum value among the photon energies of the incident light at the point where the Del_2 value becomes 0, Equation 2 A blank mask, wherein the average value of Del_2, denoted by , is -75 to -50°/eV.
3. The method of claim 2,
When the PE ₁ value is the maximum value among photon energies of incident light at a point where the Del_2 value becomes 0, and the PE ₂ value is 5.0 eV, the average value of Del_2 expressed by Equation 2 is 40 to 120°/eV In, blank mask.
delete delete 3. The method of claim 2,
The thickness of the protective layer is 25 Å or more and 80 Å or less, a blank mask.
3. The method of claim 2,
The phase difference adjusting layer has a refractive index of 2 to 4 for ArF light and an extinction coefficient of 0.3 to 0.7 for ArF light, a blank mask.
3. The method of claim 2,
The protective layer has a refractive index of 1.3 to 2 for ArF light, a blank mask.
3. The method of claim 2,
The light-shielding film comprises 44 to 60 atomic% of the chromium, a blank mask.
11. The method of claim 10,
The phase shift film and the light blocking film are included in a multilayer,
A blank mask, wherein the optical density of the multilayer with respect to ArF light is 3 or more.
A photomask manufactured with the blank mask according to claim 2 .

Images