KR20210147391A - Blankmask and Photomask - Google Patents

Abstract

The present invention relates to a blank mask in which a phase-shifting film and a light-shielding film are formed on a transparent substrate. The light-shielding film is configured to comprise a multilayer film having two or more layers including oxygen (O), or a continuous film in which at least one among nitrogen (N) and oxygen (O) is continuously changed. By increasing the etching rate of the light-shielding film and forming a light-shielding film with a low sheet resistance, the thickness of a resist film can be reduced, thereby enabling fine patterns and high-resolution images to be formed and realized.

Description

Blankmask and Photomask {Blankmask and Photomask}

The present invention relates to a blank mask and a photomask, and more particularly, to a blank mask capable of realizing high resolution and improving quality by increasing the etching rate of the light-shielding film and reducing the sheet resistance of the light-shielding film, and a photo manufactured using the same It's about the mask.

Today, in order to manufacture a photomask having high resolution and excellent quality, thinning of the resist film is required. Accordingly, in the photolithography technology, the exposure wavelength is shortened from I-Line of 365 nm to ArF of 193 nm. ), from a hardmask binary blankmask having a hardmask film and a light-shielding film to a hardmask on phase shifting blankmask in recent years.

The development of such a blank mask is to reduce the thickness of the resist film to manufacture a photomask with high resolution and excellent quality.

In order to thin the resist film, a method of increasing the etching rate of the light-shielding film by including oxygen in the light-shielding film has been recently proposed, but a problem in that the sheet resistance of the light-shielding film increases. Accordingly, the flow of electrons is disturbed during E-Beam Writing, which causes a charge-up phenomenon, which causes a pattern position error, resulting in deterioration of the photomask quality. do. Moreover, as a silicon oxide (SiO)-based material is used as the material of the hard mask film, the sheet resistance increases, which makes photomask manufacturing impossible or deteriorates the quality.

An object of the present invention is to provide a phase inversion blank mask having a light-shielding film having a fast etching rate of the light-shielding film, allowing the resist film to be thinned, and having a low sheet resistance, enabling fine pattern formation and high-resolution realization, and a photomask using the same. .

In order to achieve the above object, the present invention provides a blank mask in which a phase shift film and a light blocking film are formed on a transparent substrate, wherein the light blocking film is a multilayer film having two or more layers containing oxygen (O), or nitrogen (N) And at least one of oxygen (O) proposes a blank mask characterized in that it comprises a continuous film that changes continuously.

The light blocking layer includes a light blocking layer having an optical density per unit thickness of 0.04/nm or more, and the light blocking layer is composed of one of Cr, CrN, CrC, CrO, CrCN, CrON, CrCO, and CrCON.

In the light-shielding layer, the content of chromium (Cr) is preferably greater than the sum of the content of nitrogen (N) and oxygen (O).

The light-shielding layer has a thickness of 2 to 50% of the total thickness of the light-shielding film.

The light-shielding film has an optical density of 1.2 to 2.5 in exposure light having a wavelength of 193 nm.

The light blocking layer has a thickness of 350 to 600 Å.

The light blocking layer has an etching rate of 1.0 to 4.0 Å/sec.

The light blocking film includes a first light blocking layer having a function of controlling the etching rate and optical density of the entire light blocking film, a second light blocking layer having a function of controlling the surface resistance and etching rate of the entire light blocking film, and the light blocking layer and a third light blocking layer having a function of controlling the surface reflectance and surface resistance of the film, wherein the first light blocking layer, the second light blocking layer, and the third light blocking layer are sequentially stacked on the phase shift film.

The second light blocking layer preferably has an optical density per unit thickness of 0.04/nm or more.

In the second light blocking layer, the content of chromium (Cr) is preferably higher than the sum of the content of oxygen (O), nitrogen (N), and carbon (C).

The first light blocking layer and the third light blocking layer are composed of one of CrO, CrON, CrCO, and CrCON containing oxygen (O), and the second light blocking layer is Cr, CrN, CrC, CrO, CrCN, CrON, CrCO , CrCON.

The first light blocking layer and the third light blocking layer have a chromium (Cr) content of 30 to 50 at%, an oxygen (O) content of 5 to 40 at%, a nitrogen (N) content of 0 to 50 at%, and a carbon (C) content is 0 to 50 at%, the chromium (Cr) content of the second light blocking layer 105 is 50 to 100 at%, the oxygen (O) content is 0 to 30 at%, the nitrogen (N) content is 0 to 50 at%, carbon (C) The content is 0 to 40 at%.

The first light blocking layer has a thickness of 10 to 90% of the total thickness of the light blocking film, the second light blocking layer has a thickness of 2 to 50% of the total thickness of the light blocking layer, and the third light blocking layer has a thickness of the light blocking layer It has a thickness of 2 to 50% of the total thickness of the film formation.

The light blocking film has a total thickness of 350 to 600 Å, an optical density of 1.2 to 2.5 at an exposure wavelength of 193 nm, a surface reflectance of 20 to 40%, and a sheet resistance of 1.0 kΩ/□.

A hard mask layer may be additionally formed on the light blocking layer.

The hard mask layer has an etch selectivity of 20 or more with respect to the light blocking layer, and includes molybdenum (Mo), tantalum (Ta). Vanadium (V), cobalt (Co), nickel (Ni), zirconium (Zr), niobium (Nb), palladium (Pd), zinc (Zn), chromium (Cr), aluminum (Al), manganese (Mn), cadmium (Cd), magnesium (Mg), lithium (Li), selenium (Se), copper (Cu), hafnium (Hf), tungsten (W), silicon (Si), or , or further comprising at least one element of oxygen (O), nitrogen (N), and carbon (C) in the metal material.

According to the present invention, there is provided a photomask manufactured using the blank mask of the above configuration.

According to the present invention, the thickness of the resist film can be reduced by increasing the etching rate of the light-shielding film and forming the light-shielding film with low sheet resistance. Accordingly, there is an advantage in that it is possible to form a fine pattern and realize a high resolution.

In addition, by selectively providing a hard mask film on the light shielding film, it is possible to manufacture a blank mask having high resolution and excellent quality and a photomask using the same.

1 is a view showing a blank mask according to an embodiment of the present invention.
2 is a view showing a blank mask according to another embodiment of the present invention.

1 is a view showing a blank mask according to an embodiment of the present invention.

The blank mask 100 according to the present invention includes a phase shift film 102 , a light blocking film 103 , and a resist film 110 sequentially stacked on a transparent substrate 101 .

As the flatness of the transparent substrate 101 affects the thin film formed thereon, when the flatness of the formed surface is defined as a TIR (Total Indicated Reading) value, the value is 300 nm or less in an area of 142 mm ^{2 ,} Preferably it is controlled to 200 nm or less.

The phase shift film 102 is formed using a target made of silicon (Si) or silicon (Si) including a transition metal, and is formed in the form of a single layer, a multilayer film of two or more layers, or a continuous film. The phase shift film 102 may be formed of one of a silicon (Si) compound such as Si, SiN, SiC, SiO, SiB, SiCN, SiNO, SiBN, SiCO, SiBC, SiBO, SiNCO, SiBCN, SiBON, SiBCO, or SiBCON. have. In the case of a phase shift film whose transition metal is molybdenum (Mo), molybdenum such as MoSi, MoSiN, MoSiC, MoSiO, MoSiB, MoSiCN, MoSiNO, MoSiBN, MoSiCO, MoSiBC, MoSiBO, MoSiNCO, MoSiBCN, MoSiBON, MoSiBCO, and MoSiBCON It is preferably composed of one of silicide (MoSi) compounds.

The phase shift film 102 has a transmittance of 3 to 50% with respect to exposure light having a wavelength of 193 nm, and a phase shift amount of 160 to 200°. The phase shift film 102 may optionally be heat-treated at a temperature of 100 to 500° C. after formation in order to improve chemical resistance and flatness. Process), a furnace, etc. can be used.

The light-shielding film 103 is preferably a multi-layer film with two or more layers containing oxygen (O) in a transition metal or a continuous film in which the composition of at least one of nitrogen (N) and oxygen (O) is continuously changed. and the light blocking layer 105 having an optical density per unit thickness of 0.04/nm or more.

For process simplification, the light-shielding film 103 is preferably formed of a single layer or a continuous film of two or more layers, and it is more preferable to form a multi-layer structure of three or more layers in consideration of the optical properties and surface resistance of the light-shielding film 103 . do.

In this case, the light blocking film 103 should be made of a material having an etch selectivity to the phase shift film 102 , and is preferably made of a chromium (Cr) compound.

The light blocking film 103 preferably has a multilayer structure of the first light blocking layer 104 , the second light blocking layer 105 , and the third light blocking layer 106 sequentially stacked on the phase shift film 102 . The light-shielding film 103 is made of a chromium (Cr) compound including at least one of oxygen, nitrogen, and carbon in chromium (Cr). Preferably, the first light blocking layer 104 and the third light blocking layer 106 are composed of one of CrO, CrON, CrCO, and CrCON containing oxygen (O), and the second light blocking layer 105 is composed of Cr, CrN, It is composed of one of CrC, CrO, CrCN, CrON, CrCO, and CrCON.

The content of chromium (Cr) in the second light blocking layer 105 should be higher than the sum of the contents of oxygen (O), nitrogen (N), and carbon (C), and the optical density per unit thickness is 0.04/nm or more, preferably has an optical density of 0.05/nm or more.

In detail, the chromium (Cr) content of the first light blocking layer 104 and the third light blocking layer 106 is 30 to 50 at%, the oxygen (O) content is 5 to 40 at%, and the nitrogen (N) content is 0 to 50at%, the carbon (C) content is 0-50at%, the chromium (Cr) content of the second light blocking layer 105 is 50-100at%, the oxygen (O) content is 0-30at%, the nitrogen (N) content It is preferable that the silver is 0 to 50 at%, and the carbon (C) content is 0 to 40 at%.

The first light blocking layer 104 has a thickness of 10 to 90% of the total thickness of the light blocking layer 103 , and serves to control the etch rate and optical density of the entire light blocking layer 103 . Accordingly, when the oxygen (O) content is 5 at% or less, the etching rate of the light-blocking layer 103 is slowed, so that it is difficult to thin the resist layer 110 . When the oxygen content is 40at% or more, the aspect ratio of the pattern becomes 2 or more due to an increase in the thickness of the first light-blocking layer 104 for controlling the optical density of the light-blocking film 103, and the pattern collapses accordingly As a result, the occurrence of defects increases.

The second light blocking layer 105 has a thickness of 2 to 50% of the total thickness of the light blocking layer 103 , and serves to control the surface resistance and etching rate of the entire light blocking layer 103 . When the content of chromium (Cr) in the second light blocking layer 105 is 50 at% or less or when the thickness of the second light blocking layer 105 is 2% or less of the total thickness of the light blocking layer 103, the surface resistance increases, so the photomask Image distribution occurs due to the charge-up phenomenon during manufacturing, making it difficult to manufacture a photomask. When the thickness of the second light blocking layer 105 is 50% or more of the total thickness of the light blocking layer 103 , the etching rate of the light blocking layer 103 is slowed, making it difficult to thin the resist layer 110 . In consideration of this, the optical density per unit thickness of the second light blocking layer 105 is set to 0.04/nm or more, preferably 0.05/nm or more.

The third light blocking layer 105 has a thickness of 2 to 50% of the total thickness of the light blocking film 103 , and serves to control the surface reflectance and surface resistance of the light blocking film 103 . When the oxygen (O) content of the third light blocking layer 105 is 5 at% or less, the reflectance of the light blocking layer 103 with respect to the exposure light increases, so that a flare phenomenon occurs during wafer exposure. When the oxygen (O) content of the third light blocking layer 105 is 40 at% or more, the surface resistance increases and a charge-up phenomenon occurs.

Accordingly, the light-shielding film 103 according to the present invention is formed as a multilayer film with two or more layers containing oxygen (O) or a continuous film in which the composition of at least one of nitrogen (N) and oxygen (O) is continuously changed, , the second light blocking layer 105 having an optical density per unit thickness of 0.04/nm or more. In addition, the light blocking film 103 having the above configuration has a total thickness of 350 to 600 Å, an optical density of 1.2 to 2.5 at an exposure wavelength of 193 nm, a surface reflectance of 20 to 40%, and a sheet resistance of 1.0 kΩ/□.

The light blocking film 103 may be selectively heat-treated at 100 to 500° C. after forming the film to improve chemical resistance and flatness.

The resist film 110 has a thickness of 60 nm to 150 nm, and is preferably a chemically amplified resist (CAR).

2 is a view showing a blank mask according to another embodiment of the present invention.

In the blank mask 100 of this embodiment, a hard mask film 107 is additionally provided between the light blocking film 103 and the resist film 110, and other transparent substrates 101, phase shift film 102, The structures of the light-shielding film 103 and the resist film 110 are the same as those of the above-described embodiment of FIG. 1 .

The hard mask layer 107 preferably has an etch selectivity of 20 or more with respect to the light blocking layer 103 . The hard mask layer 107 is made of molybdenum (Mo) or tantalum (Ta). Vanadium (V), cobalt (Co), nickel (Ni), zirconium (Zr), niobium (Nb), palladium (Pd), zinc (Zn), chromium (Cr), aluminum (Al), manganese (Mn), cadmium (Cd), magnesium (Mg), lithium (Li), selenium (Se), copper (Cu), hafnium (Hf), tungsten (W), silicon (Si), or , or further comprising at least one element of oxygen (O), nitrogen (N), and carbon (C) in the metal material.

The hard mask film 107 may also be formed of silicon (Si) alone, or silicon oxide (SiO), silicon nitride (SiN), silicon carbide (SiC), silicon oxynitride (SiON), silicon carbide oxide (SiCO), silicon carbonitride (SiCN) and silicon oxynitride (SiCON) may be formed of one of a silicon (Si) compound.

The hard mask film 107 preferably has a thickness of 2 to 15 nm in order to reduce the thickness of the resist film 110 . When the thickness is 2 nm or less, when the light blocking film 103 is patterned, the hard mask layer 107 is thin and surface damage occurs in the light blocking layer 103 . When the thickness is 15 nm or more, since the thickness of the resist film 110 increases, it becomes difficult to implement a high-precision pattern due to electron scattering during electron beam exposure.

In addition, by selectively forming an etch stop layer (not shown) between the substrate 101 and the phase shift layer 102 or between the phase shift layer 102 and the light blocking layer 103 , pattern precision can be increased.

Hereinafter, specific embodiments of the present invention will be described.

(Example 1)

The present embodiment discloses a phase inversion blank mask or a phase inversion blank mask for a hard mask in which a light-shielding film having a low sheet resistance and an excellent etching rate is formed, and manufacturing a photomask using the same.

First, a transparent substrate having a size of 6 inch × 6 inch × 0.25 inch (width × length × thickness) and controlled with flatness (TIR) of 200 nm or less and birefringence of 2 nm/6.35 mm was prepared.

Thereafter, a molybdenum silicide (MoSi) target is mounted on a DC magnetron sputtering apparatus, process gas Ar: N ₂ = 5.5 sccm: 23.0 sccm is injected, and a process power of 0.65 kW is applied, molybdenum nitride silicide ( A single-layer phase shift film made of MoSiN) was formed.

Thereafter, heat treatment was performed for the phase shift film at a temperature of 350° C. for 20 minutes using a vacuum rapid thermal process. As a result of measuring transmittance and phase amount at a wavelength of 193 nm, transmittance 6.02% , the phase amount was 183.5 degrees. In addition, as a result of thickness measurement using XRR equipment, the phase shift film showed a thickness of 67.5 nm.

Then, using a chromium (Cr) target on the phase shift film, process gases Ar: N ₂ : CO ₂ = 3.0 sccm: 10.0 sccm: 6.8 sccm are injected, and a process power of 0.75 kW is applied to oxidize carbonization. A first light blocking layer of chromium (CrCON) was formed. The thickness of the first light blocking layer was measured to be 46.5 nm as a result of thickness measurement using XRR equipment.

Thereafter, the process gas Ar: N ₂ : CO ₂ = 5.0 sccm: 5.0 sccm: 2.0 sccm is injected, and a process power of 1.40 kW is applied, so that the second light blocking layer made of chromium carbon dioxide (CrCON) is first shielded from light. formed on the layer. The thickness of the second light blocking layer was measured to be 4.2 nm as a result of thickness measurement using XRR equipment. At this time, as a result of measuring transmittance at 193 nm using n&k 3700 (UV-VIS Spectrometer) equipment for the second light blocking layer, the optical density per unit thickness was found to be 0.058/nm.

Thereafter, the process gas Ar: N ₂ : CO ₂ = 3.0 sccm: 5.0 sccm: 7.5 sccm was injected, and a process power of 0.75 kW was applied to form a third light blocking layer of chromium carbon dioxide (CrCON) as a second light blocking layer. formed on the As a result of thickness measurement using XRR equipment for the third light-shielding layer, it was measured to have a thickness of 4.3 nm.

The total thickness of the light blocking film formed with the first to third light blocking layers was 55.0 nm, and as a result of measuring the optical density and reflectance in exposure light having a wavelength of 193 nm, an optical density of 1.84 and a reflectance of 28.1% were obtained. And, as a result of measuring the optical density and reflectance of exposure light having a wavelength of 193 nm according to the formation of the light blocking film on the phase shift film, an optical density of 3.05 and a reflectance of 28.8% were obtained.

Thereafter, the light-shielding film was heat-treated at a temperature of 250° C. for 20 minutes using a vacuum rapid thermal process.

After confirming the composition ratio of the light-shielding film using AES equipment, the first light-shielding film had a chromium (Cr) content of 40.3 at%, a nitrogen (N) content of 23.0 at%, an oxygen (O) content of 20.4 at%, and a carbon ( C) The content is 16.3at%, the chromium (Cr) content of the second light shielding film is 54.9at%, the nitrogen (N) content is 27.4at%, the oxygen (O) content is 3.7at%, the carbon (C) content is 14.0at %, it was confirmed that the chromium (Cr) content of the third light shielding film was 41.5 at%, the nitrogen (N) content was 22.9 at%, the oxygen (O) content was 19.0 at%, and the carbon (C) content was 16.6 at%.

Then, a chemically amplified resist film was spin-coated to a thickness of 150 nm on the light-shielding film to finally prepare a phase shift film blank mask.

(Example 2)

A phase shift film and a light-shielding film were formed in the same manner as in Example 1.

Then, using a silicon (Si) target doped with boron (B) on the light-shielding film, process gases Ar: N ₂ : NO = 7.0 sccm: 7.0 sccm: 5.0 sccm are injected, and a process power of 0.7 kW is applied Thus, a hard mask film made of silicon oxynitride (SiON) having a thickness of 10 nm was formed.

Then, a chemically amplified resist film was spin-coated to a thickness of 100 nm on the hard mask film to finally prepare a phase shift film blank mask for the hard mask.

(Example 3)

A phase shift film was formed in the same manner as in Example 1.

Then, using a chromium (Cr) target on the phase shift film, process gases Ar: N ₂ : CO ₂ = 3.0 sccm: 10.0 sccm: 6.5 sccm are injected, and a process power of 0.62 kW is applied to oxidize carbonization. A first light blocking layer of chromium (CrCON) was formed. The thickness of the first light blocking layer was measured to be 7.8 nm as a result of thickness measurement using XRR equipment.

Thereafter, a process gas Ar: N ₂ =5.0 sccm: 9.0 sccm was injected, and a process power of 1.40 kW was applied to form a second light blocking layer made of chromium nitride (CrN) on the first light blocking layer. As a result of thickness measurement using XRR equipment for the second light-shielding layer, it was measured to have a thickness of 22.0 nm. At this time, as a result of measuring transmittance at 193 nm using n&k 3700 (UV-VIS Spectrometer) equipment for the second light-shielding layer, the optical density per unit thickness was It was expressed as 0.052/nm.

Thereafter, the process gas Ar: N ₂ : CO ₂ = 3.0 sccm: 10.0 sccm: 6.0 sccm was injected, and a process power of 0.62 kW was applied to form a third light blocking layer of chromium carbon dioxide (CrCON) as a second light blocking layer. formed on the The thickness of the third light blocking layer was measured to be 13.2 nm as a result of thickness measurement using XRR equipment.

The total thickness of the light blocking film on which the first to third light blocking layers are formed was 43.0 nm, and as a result of measuring the optical density and reflectance in exposure light having a wavelength of 193 nm, an optical density of 1.82 and a reflectance of 22.4% were obtained. As a result of measuring the optical density and reflectance of exposure light with a wavelength of 193 nm according to the formation of a light blocking film on the phase shift film, an optical density of 3.03 and a reflectance of 22.9% were obtained.

Thereafter, the light-shielding film was heat-treated at a temperature of 250° C. for 20 minutes using a vacuum rapid thermal process.

After confirming the composition ratio of the light-shielding film using AES equipment, the first light-shielding layer had a chromium (Cr) content of 39.4 at%, a nitrogen (N) content of 23.1 at%, an oxygen (O) content of 20.4 at%, and carbon (C) The content is 17.1 at%, the chromium (Cr) content of the second light-shielding layer is 58.5 at%, the nitrogen (N) content is 41.5 at%, the chromium (Cr) content of the third light-shielding layer is 38.9 at%, nitrogen It was confirmed that the (N) content was 22.3 at%, the oxygen (O) content was 22.3 at%, and the carbon (C) content was 16.5 at%.

Then, a chemically amplified resist film was spin-coated to a thickness of 150 nm on the light blocking film to finally prepare a phase shift film blank mask in cm.

(Example 4)

A phase shift film and a light-shielding film were formed in the same manner as in Example 3.

Then, using a silicon (Si) target doped with boron (B) on the light-shielding film, process gases Ar: N ₂ : NO = 7.0 sccm: 7.0 sccm: 5.0 sccm are injected, and a process power of 0.7 kW is applied. , a hard mask film made of silicon oxynitride (SiON) having a thickness of 10 nm was formed.

Then, a chemically amplified resist film was spin-coated to a thickness of 100 nm on the hard mask film to finally prepare a phase shift film blank mask for the hard mask.

(Comparative Example 1)

A phase shift film was formed in the same manner as in Example 3.

Then, using a chromium (Cr) target on the phase shift film, process gases Ar: N ₂ : CO ₂ = 3.0 sccm: 10.0 sccm: 6.5 sccm are injected, and a process power of 0.62 kW is applied to oxidize carbonization. A first light blocking layer of chromium (CrCON) was formed. The thickness of the first light blocking layer was measured to be 7.5 nm as a result of thickness measurement using XRR equipment.

Thereafter, the process gas Ar: N ₂ : CO ₂ = 5.0 sccm: 15.8 sccm: 2.0 sccm was injected, and a process power of 1.40 kW was applied to make the second light-shielding layer made of chromium carbon dioxide (CrCON) to be the first blocking light. formed on the layer. As a result of thickness measurement using XRR equipment for the second light-shielding layer, it was measured to have a thickness of 38.0 nm. At this time, as a result of measuring transmittance at 193 nm using n&k 3700 (UV-VIS Spectrometer) equipment for the second light-shielding layer, the optical density per unit thickness was 0.038/nm.

Thereafter, the process gas Ar: N ₂ : CO ₂ = 3.0 sccm: 10.0 sccm: 6.0 sccm was injected, and a process power of 0.62 kW was applied to form a third light blocking layer of chromium carbon dioxide (CrCON) as a second light blocking layer. formed on the The thickness of the third light blocking layer was measured to be 9.5 nm as a result of thickness measurement using XRR equipment.

The total thickness of the light blocking film formed with the first to third light blocking layers was 55.0 nm, and as a result of measuring the optical density and reflectance in exposure light having a wavelength of 193 nm, an optical density of 1.80 and a reflectance of 23.2% were obtained. As a result of measuring the optical density and reflectance of exposure light having a wavelength of 193 nm according to the formation of the light blocking film on the phase shift film, an optical density of 3.00 and a reflectance of 23.8% were obtained.

Thereafter, the light-shielding film was heat-treated at a temperature of 250° C. for 20 minutes using a vacuum rapid thermal process.

After confirming the composition ratio of the light-shielding film using AES equipment, the first light-shielding layer had a chromium (Cr) content of 39.4 at%, a nitrogen (N) content of 23.1 at%, an oxygen (O) content of 20.4 at%, and carbon (C) content is 17.1 at%, chromium (Cr) content of the second light shielding layer is 44.3 at%, nitrogen (N) content is 31.8 at%, oxygen (O) content is 10.4 at%, carbon (C) content is 13.5 at%, 38.9 at% chromium (Cr) content, 22.3 at% nitrogen (N) content, 22.3 at% oxygen (O) content, and 16.5 at% carbon (C) content of the third light blocking layer Confirmed.

Then, a chemically amplified resist film was spin-coated to a thickness of 150 nm on the light blocking film to finally prepare a phase shift film blank mask.

(Comparative Example 2)

A phase shift film and a light-shielding film were formed in the same manner as in Comparative Example 1.

Then, using a silicon (Si) target doped with boron (B) on the light-shielding film, process gases Ar: N ₂ : NO = 7.0 sccm: 7.0 sccm: 5.0 sccm are injected, and a process power of 0.7 kW is applied. , a hard mask film made of silicon oxynitride (SiON) having a thickness of 10 nm was formed.

Then, a chemically amplified resist film was spin-coated to a thickness of 100 nm on the hard mask film to finally prepare a phase shift film blank mask for the hard mask.

Evaluation of the etching rate of the light-shielding film

The optical density and average etching rate of the phase shift blank mask according to the present invention described above, and the residual film thickness of the resist film after pattern formation were measured.

Evaluation of etch rate and resist residual thickness of light-shielding film Example 1 Example 3 Comparative Example 1
phase shift film constituent MoSiN MoSiN MoSiN thickness 67.5nm 67.5nm 67.5nm transmittance 6.02% 6.02% 6.02% Optical Density @193nm light blocking film 1.84 1.82 1.80 With phase shift film 3.05 3.03 3.00 Average etching rate of light-shielding film 1.74Å/sec 1.07 Å/sec 1.18Å/sec resist film film thickness 150nm 150nm 150nm Residue after etching 63nm 42nm 25nm

Referring to Table 1, Examples 1, 3 and Comparative Example 3 all showed an optical density including a phase shift film of 2.5 to 3.5, which was satisfactory for use as a photomask after pattern formation.

In the case of the etching rate of the light-shielding film, Examples 1, 3 and Comparative Example 3 all showed an etching rate of 1.0/sec to 4.0/sec, and in the case of Example 1, the residual thickness of the resist film was 63 nm. is showing

Sheet resistance evaluation of light-shielding film

In order to analyze the charge-up phenomenon of the phase inversion blank mask and the phase inversion blank mask for a hard mask according to the present invention, the sheet resistance was measured using a 4-point probe.

Sheet resistance evaluation result Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2
phase shift film constituent MoSiN MoSiN MoSiN MoSiN MoSiN MoSiN thickness 67.5nm 67.5nm 67.5nm 67.5nm 67.5nm 67.5nm transmittance 6.02% 6.02% 6.02% 6.02% 6.02% 6.02%
2nd light blocking layer Optical density per unit thickness 0.058/nm 0.058/nm 0.052/nm 0.052/nm 0.038/nm 0.038/nm Cr content 54.9at% 54.9at% 58.5at% 58.5at% 44.at% 44.at% light blocking film optical density 1.84 1.84 1.82 1.82 1.80 1.80 thickness 55nm 55nm 43nm 43nm 55nm 55nm hard mask constituent SiON SiON SiON thickness 10nm 10nm 10nm Sheet resistance of the top layer (Ω/□) 397Ω/□ 486Ω/□ 285Ω/□ 343Ω/□ 4,241Ω/□ 5,981Ω/□

Referring to Table 2, the sheet resistance measurement results according to the light-shielding film constituting the phase inversion blank mask and the hard mask blank mask according to Examples 1 to 4 and Comparative Examples 1 and 2, Examples 1 to 4 according to the present invention In the case of 1.0 kΩ/□ or less, it was 4.20 kΩ/□ or more in Comparative Example 1, and 5,90 kΩ/□ or more in Comparative Example 2 in which a hard mask film was additionally formed. I was able to confirm that I had.

Accordingly, in Comparative Examples, the flow of electrons is disturbed during E-Beam Writing, and a charge-up phenomenon occurs, which causes a pattern position error, thereby causing the photomask. quality deteriorates.

Therefore, in the phase shift blank mask and the phase shift blank for hard mask according to the present invention, the resist film can be thinned and the charge-up phenomenon does not occur during E-Beam Writing, so high-quality photo Masks can be made.

Above, the present invention will be described in detail through examples of the present invention with reference to the drawings, but the examples are only used for the purpose of illustration and description of the present invention and limit the meaning of the present invention described in the claims. It is not used to limit the scope. Therefore, those of ordinary skill in the art will understand that various modifications and equivalent other embodiments are possible from the embodiments. Therefore, the true technical protection scope of the present invention will have to be determined by the technical matters of the claims.

100: blank mask 101: transparent substrate
102: phase shift film 103: light blocking film
104: first light blocking layer 105: second light blocking layer
106: third light blocking layer 107: hard mask film
110: resist film

Claims (17)

In the blank mask in which a phase shift film and a light-shielding film are formed on a transparent substrate,
The light-shielding film is a multilayer film with two or more layers containing oxygen (O), or a blank mask comprising a continuous film in which at least one of nitrogen (N) and oxygen (O) is continuously changed.
The method of claim 1,
The light-shielding film includes a light-shielding layer having an optical density per unit thickness of 0.04/nm or more,
The light blocking layer is a blank mask, characterized in that it is composed of one of Cr, CrN, CrC, CrO, CrCN, CrON, CrCO, CrCON.
3. The method of claim 2,
The light-shielding layer is a blank mask, characterized in that the content of chromium (Cr) is greater than the sum of the content of nitrogen (N) and oxygen (O).
3. The method of claim 2,
A blank mask having a thickness of 2-50% of the total thickness of the light-shielding film of the light-shielding layer
The method of claim 1,
The light blocking film is a blank mask, characterized in that it has an optical density of 1.2 to 2.5 in exposure light of a wavelength of 193 nm.
The method of claim 1,
The blank mask, characterized in that the light-shielding film has a thickness of 350 ~ 600Å.
The method of claim 1,
The light-shielding film is a blank mask, characterized in that it has an etching rate of 1.0 ~ 4.0 Å / sec.
The method of claim 1,
The light-shielding film is
a first light-blocking layer having a function of controlling the etching rate and optical density of the entire light-shielding film;
a second light-blocking layer having a function of controlling the surface resistance and etching rate of the entire light-shielding film; and
a third light-blocking layer having a function of controlling the surface reflectance and surface resistance of the light-shielding film;
The blank mask, characterized in that the first light blocking layer, the second light blocking layer, and the third light blocking layer are sequentially stacked on the phase shift film.
9. The method of claim 8,
The second light-blocking layer has an optical density per unit thickness of 0.04/nm or more.
9. The method of claim 8,
The second light blocking layer is a blank mask, characterized in that the content of chromium (Cr) is higher than the sum of the contents of oxygen (O), nitrogen (N), and carbon (C).
9. The method of claim 8,
The first light blocking layer and the third light blocking layer are composed of one of CrO, CrON, CrCO, and CrCON containing oxygen (O),
The second light blocking layer is a blank mask, characterized in that it is composed of one of Cr, CrN, CrC, CrO, CrCN, CrON, CrCO, CrCON.
12. The method of claim 11,
The first light blocking layer and the third light blocking layer have a chromium (Cr) content of 30 to 50 at%, an oxygen (O) content of 5 to 40 at%, a nitrogen (N) content of 0 to 50 at%, and a carbon (C) content is 0-50 at%,
The second light blocking layer 105 has a chromium (Cr) content of 50 to 100 at%, an oxygen (O) content of 0 to 30 at%, a nitrogen (N) content of 0 to 50 at%, and a carbon (C) content of 0 to A blank mask, characterized in that 40at%.
13. The method of claim 12,
The first light blocking layer has a thickness of 10 to 90% of the total thickness of the light blocking film,
The second light blocking layer has a thickness of 2 to 50% of the total thickness of the light blocking film,
The third light blocking layer is a blank mask, characterized in that it has a thickness of 2 to 50% of the total thickness of the light blocking film.
14. The method of claim 13,
The light-shielding film has a total thickness of 350 to 600 Å, an optical density of 1.2 to 2.5 at an exposure wavelength of 193 nm, a surface reflectance of 20 to 40%, and a sheet resistance of 1.0 kΩ/□.
The method of claim 1,
The blank mask further comprising a hard mask film formed on the light-shielding film.
16. The method of claim 15,
The hard mask layer has an etch selectivity of 20 or more with respect to the light blocking layer,
Molybdenum (Mo), tantalum (Ta). Vanadium (V), cobalt (Co), nickel (Ni), zirconium (Zr), niobium (Nb), palladium (Pd), zinc (Zn), chromium (Cr), aluminum (Al), manganese (Mn), cadmium (Cd), magnesium (Mg), lithium (Li), selenium (Se), copper (Cu), hafnium (Hf), tungsten (W), silicon (Si), or Or, a blank mask comprising at least one element of oxygen (O), nitrogen (N), and carbon (C) in the metallic material.
A photomask manufactured using the blank mask of any one of claims 1 to 16.

Images