Laminate for blank mask and method for manufacturing same

Abstract

To provide a laminate for a blank mask in which ions that may cause growing defects during exposure have been effectively reduced.SOLUTION: A laminate for a blank mask includes: a light-transmitting layer; and a phase inversion film disposed on the light-transmitting layer; where residual ions measured at a surface of the phase inversion film through ion chromatography comprises at least one of sulfate ions in a concentration from 0 ng / cm2 to 0.05 ng / cm2 inclusive, nitric oxide ions in a concentration from 0 ng / cm2 to 0.5 ng / cm2 inclusive, and ammonium ions in a concentration from 0 ng / cm2 to 5 ng / cm2 inclusive, where the sum of the concentrations of the residual ions is greater than 0. Also provided is a manufacturing method for the same.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The embodiment relates to a laminate for a blank mask and a method for manufacturing the same. [Background technology]

[0002] The increasing integration of semiconductor devices has led to a demand for finer circuit patterns in semiconductor devices, which has led to an increase in the importance of lithography, a technology for developing circuit patterns on the surface of a wafer using a photomask.

[0003] In order to develop finer circuit patterns, the exposure light source used in the exposure process must have a shorter wavelength. The most commonly used exposure light source is the ArF excimer laser (wavelength 193 nm).

[0004] Depending on the application, the blank mask may include a light-transmitting layer and a phase shifting film or a light-shielding film formed on the light-transmitting layer. The light-transmitting layer may be manufactured by shaping a material having light-transmitting properties, followed by polishing and cleaning processes.

[0005] As the circuit patterns developed on wafers become finer, it is necessary to more effectively suppress defects that may occur during the blank mask manufacturing process and defects that may grow during exposure. In particular, sulfate ions (SO4 2- ), nitrate ions (NO2 - , NO3 - ), ammonium ion (NH4 + ), chloride ions (Cl - ) and other factors must be controlled to prevent unintended pattern transfer.

[0006] The above-mentioned background art is technical information that the inventor possessed for the purpose of deriving the embodiments or that he acquired in the process of deriving the embodiments, and is not necessarily publicly known art that was disclosed to the general public prior to the filing of the present invention.

[0007] Related prior art includes "Method for forming a photomask that suppresses haze" disclosed in Korean Patent Publication No. 10-0935730. Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the embodiment is to provide a laminate for a blank mask in which ions that may induce growing defects during exposure are effectively reduced.

[0009] Another object of the present embodiment is to provide a laminate for a blank mask that has good haze characteristics and suppresses haze-related defects.

[0010] Another object of the present embodiment is to provide a method for manufacturing a laminate for a blank mask that intentionally maintains ammonium ions at a specific concentration by reacting with residual hydrogen through a unique nitrogen treatment during the formation of a phase shift film, thereby reducing ions that cause haze. [Means for solving the problem]

[0011] In order to achieve the above object, a laminate for a blank mask according to an embodiment includes: a light-transmitting layer and a phase shift film disposed on the light-transmitting layer; Residual ions measured on the surface of the phase inversion membrane via ion chromatography were Concentration is 0ng / cm 2 More than 0.05ng / cm 2 Sulfate ions, which are: Concentration is 0ng / cm 2 More than 0.5ng / cm 2 Nitrogen oxide ions, which are: Concentration is 0ng / cm 2 More than 5ng / cm 2 At least one of the following ammonium ions is included: The sum of the concentrations of the residual ions can exceed zero.

[0012] In one embodiment, the residual ions are chloride ions (Cl - ) and the concentration of the chloride ions is 0 ng / cm 2 More than 0.05ng / cm 2 It may be the following:

[0013] In one embodiment, the phase shift layer may include molybdenum and at least one element selected from the group consisting of silicon, nitrogen, oxygen, and carbon.

[0014] In one embodiment, the concentration of sulfate ions is 0 ng / cm 2 More than 0.05ng / cm 2 below, The concentration of the nitrogen oxide ions is 0 ng / cm 2 More than 0.5ng / cm 2 It may be the following:

[0015] In one embodiment, the concentration of nitrogen oxide ions is: Nitrite ion (NO2 - ) concentration is 0ng / cm 2 More than 0.01ng / cm 2 below, Nitrate ions (NO3 - ) concentration is 0ng / cm 2 More than 0.04ng / cm 2 It may be the following:

[0016] In order to achieve the above object, a method for manufacturing a laminate for a blank mask according to an embodiment includes: a deposition step of depositing a phase shift film on the light transmitting layer; a heat treatment step of heat-treating the phase shift film; a washing step of washing the heat-treated phase shift film; In the film forming step, a gas is introduced into a nitrogen atmosphere of 30% by volume or more and 70% by volume or less, and the concentration of ammonium ions on the surface of the film to be formed is 50 ng / cm 2 More than 110ng / cm 2The nitrogen treatment process includes: The cleaning step includes a first cleaning process of applying ultraviolet light and ozone water to the heat-treated phase shift film, and a second cleaning process of applying carbonated water and hydrogen water to the phase shift film after the first cleaning process. The residual ions measured on the surface of the phase shift film after the washing step were: Concentration is 0ng / cm 2 More than 0.05ng / cm 2 Sulfate ions, which are: Concentration is 0ng / cm 2 More than 0.5ng / cm 2 Nitrogen oxide ions, which are: Concentration is 0ng / cm 2 More than 5ng / cm 2 At least one of the following ammonium ions is included: The sum of the concentrations of the residual ions may be greater than zero.

[0017] In one embodiment, the deposition step includes: A target containing molybdenum and silicon is placed, and sputtering is performed in a reactive gas atmosphere. The reactive gas may include one or more selected from the group consisting of oxygen, nitrogen, and carbon.

[0018] In one embodiment, the heat treatment step comprises: It may be performed at a temperature of 300° C. or more and 500° C. or less for a time of 10 minutes or more and 120 minutes or less.

[0019] In one embodiment, in the first cleaning step of the cleaning step, the ultraviolet light has a wavelength of 100 nm to 250 nm and is 10 mW / cm 2 More than 100mW / cm 2 It may be irradiated with:

[0020] In one embodiment, the washing step comprises: a third cleaning step of adding hydrogen water to the phase shift film after the second cleaning step; and A fourth cleaning process may be included in which carbonated water is added to the phase shift film after the third cleaning process and the film is dried.

[0021] In one embodiment, the phase shifter film subjected to the cleaning step may have a reduction rate of nitrogen oxide ions of 50% to 98% according to the following formula 1 compared to the phase shifter film subjected to the deposition step.

[0022] [Formula 1] Reduction rate (%) = {(content of nitrogen oxide ions after film formation step - content of nitrogen oxide ions after cleaning step) / (content of nitrogen oxide ions after the film formation step)} × 100%

[0023] In order to achieve the above object, a laminate for manufacturing a blank mask according to an embodiment includes: a light-transmitting layer and a phase shift film disposed on the light-transmitting layer; Residual ions measured on the surface of the phase inversion membrane via ion chromatography were Concentration is 0ng / cm 2 More than 0.05ng / cm 2 sulfate ions, which are: Concentration is 0ng / cm 2 More than 2ng / cm 2 Contains at least one of the following nitrogen oxide ions: Concentration is 50ng / cm 2 More than 110ng / cm 2 containing an ammonium ion, The sum of the concentrations of sulfate ions and nitrogen oxide ions may be greater than zero. [Effects of the Invention]

[0024] The laminate for blank masks according to the embodiment effectively reduces sulfate ions, nitrogen oxide ions, ammonium ions, etc., thereby preventing unintended pattern transfer during the exposure process, and can be applied to semi-finished and finished blank masks for forming high-quality integrated circuit patterns. [Brief explanation of the drawings]

[0025] [Figure 1] 1 is a photograph taken through a scanning electron microscope of the surface of a phase shift film (MoSi) having a growth defect (haze) and an intaglio pattern that partially exposes the light transmission layer (Q'z) in an experimental example. [Figure 2] 1 is a photograph taken through a scanning electron microscope of the surface of a phase shift film having no growing defects in an experimental example. BEST MODE FOR CARRYING OUT THE INVENTION

[0026] DETAILED DESCRIPTION OF THE INVENTION One or more exemplary embodiments will now be described in detail with reference to the accompanying drawings so as to be readily understood by those skilled in the art. However, the exemplary embodiments may be embodied in many different forms and are not limited to the embodiments set forth herein. Like reference numerals are used throughout the specification to refer to like parts.

[0027] In this specification, when a certain configuration "includes" another configuration, this does not mean that it excludes the other configurations, and that it may further include the other configurations, unless otherwise specified.

[0028] In this specification, when a certain component is said to be "connected" to another component, this includes not only the case where the components are "directly connected" but also the case where the components are "connected via another component between them."

[0029] In this specification, the term "B is located on A" means that B is located on A in direct contact with A, or that B is located on A with another layer located therebetween, and is not to be interpreted as being limited to B being located in contact with the surface of A.

[0030] As used herein, the term "combinations thereof" contained in a Markush expression means a mixture or combination of one or more elements selected from the group of elements set forth in the Markush expression, and means including one or more elements selected from the group of elements.

[0031] In this specification, the expression "A and / or B" means "A, B, or A and B."

[0032] In this specification, terms such as "first", "second" or "A", "B" are used to distinguish identical terms from each other unless otherwise specified.

[0033] In this specification, unless otherwise specified, the singular expression is to be construed as including the singular or plural as the context requires.

[0034] Laminate for blank mask The laminate for a blank mask according to the embodiment includes: a light-transmitting layer and a phase shift film disposed on the light-transmitting layer; Residual ions measured on the surface of the phase inversion membrane via ion chromatography were Concentration is 0ng / cm 2 More than 0.05ng / cm 2 Sulfate ions, which are: Concentration is 0ng / cm 2 More than 0.5ng / cm 2 Nitrogen oxide ions, which are: Concentration is 0ng / cm 2 More than 5ng / cm 2 At least one of the following ammonium ions is included: The sum of the concentrations of the residual ions may be greater than zero.

[0035] The light-transmitting layer may be made of a material that is translucent to exposure light in the wavelength bands of 193 nm and 248 nm emitted from a light source such as argon fluoride (ArF) or krypton fluoride (KrF). The light-transmitting layer may be made of soda lime, quartz glass, calcium fluoride, or the like, and may be quartz glass, for example.

[0036] The light-transmitting layer may have a transmittance of at least 85% to 100% for a laser having a wavelength of 193 nm and using argon fluoride (ArF) as a light source.

[0037] A phase shift film is a thin film that attenuates the intensity of the exposure light passing through it and adjusts the phase difference, thereby substantially suppressing diffracted light generated at the edges of the photomask pattern.

[0038] The phase shift layer may include molybdenum and one or more elements selected from the group consisting of silicon, nitrogen, oxygen, and carbon, and may include, for example, MoSi, MoSiN, MoSiO, MoSiC, MoSiCN, MoSiCO, MoSiON, and MoSiCON.

[0039] When the phase shift film contains at least MoSi, Molybdenum 0.001at% to 10at%; and It can contain silicon 20 at% to 99 at%; Nitrogen 0.001at%~65at%; Oxygen 0.1 at% to 35 at%; and It may also contain 0.001 at % to 20 at % of carbon.

[0040] The phase shift film is Molybdenum 0.001at% to 5.5at%; and It can contain silicon 25 at% to 98 at%; Nitrogen 0.001at%~60at%; Oxygen 1.0 at% to 30 at%; and It may also contain 0.001 at % to 15 at % of carbon.

[0041] The phase shift film may have a thickness of approximately 15 nm to 90 nm.

[0042] The phase shift film may have a transmittance of 1% to 30% or 3% to 10% for a 193 nm laser using argon fluoride (ArF) as a light source. The phase shift film may also have a phase difference of 170° to 190° or 175° to 185° for a 193 nm laser using argon fluoride (ArF) as a light source. In this case, the resolution can be improved when the blank mask laminate is used as a photomask.

[0043] The surface of the phase shifter may have a residual ion content measured by ion chromatography. A specific procedure for measuring the residual ion content by ion chromatography is described in the following experimental examples.

[0044] The phase shift layer may have reduced nitrogen oxide ions or sulfate ions by intentionally inducing a reaction with residual hydrogen through a nitrogen treatment specific to the embodiment during deposition to form ammonium ions at a specific concentration.

[0045] The concentration of sulfate ions in the residual ions of the phase shift film is 0 ng / cm 2 More than 0.05ng / cm 2 It may be less than 0.001 ng / cm 2 More than 0.03ng / cm 2 It may be less than 0.001 ng / cm 2 More than 0.02ng / cm 2 or less, or 0.001 ng / cm 2 More than 0.01ng / cm 2 It may be the following:

[0046] The concentration of nitrogen oxide ions in the residual ions of the phase shift film is 0 ng / cm 2 More than 0.5ng / cm 2 It may be less than 0.001 ng / cm 2 More than 0.4ng / cm 2 It may be less than 0.001 ng / cm 2 More than 0.1ng / cm 2 or less, or 0.001 ng / cm 2 More than 0.03ng / cm 2 It may be the following:

[0047] The concentration of the nitrogen oxide ions is specifically determined by the concentration of nitrite ions (NO2 - ) concentration is 0ng / cm 2 More than 0.01ng / cm 2 It may be nitrate ions (NO3 - ) concentration is 0ng / cm 2 More than 0.04ng / cm 2 or nitrite ions (NO2 - ) concentration is 0ng / cm 2 More than 0.005ng / cm 2 It may be nitrate ions (NO3 - ) concentration is 0.001ng / cm 2 More than 0.03ng / cm 2 It may be the following:

[0048] The concentration of ammonium ions in the residual ions of the phase shift film is 0 ng / cm 2 More than 5ng / cm 2 or less, or 0.001 ng / cm 2 More than 3ng / cm 2 It may be the following:

[0049] The residual ions in the phase shift film are chloride ions (Cl - ) to 0ng / cm 2 More than 0.05ng / cm 2 or 0.001 ng / cm 2 More than 0.03ng / cm2 It may be included in the following concentrations:

[0050] The phase shift layer may be substantially free of ions that cause growth defects through a specific nitrogen treatment during deposition, as described below. The phase shift layer has such a concentration of residual ions that it can effectively suppress the occurrence of growth defects during an exposure process when used in a photomask.

[0051] When the phase shift film is irradiated with light of 193 nm wavelength for 120 minutes, the number of growing defects is 0.01 / cm 2 The 193 nm wavelength light irradiation may be performed using a UV particle accelerator under conditions of a cumulative exposure energy of 10 kJ, a temperature of 23°C, and a relative humidity of 45%. The growing defects refer to defects or elements that grow and cause haze when irradiated with light of the wavelength described above. They may appear on the surface of the phase shift film in the form of black spots of approximately 50 nm or less, and the number of these can be measured by observing with a scanning electron microscope (SEM) as shown in FIG. 1. If no growing defects occur, no black spots of 50 nm or less will appear when observed with a scanning electron microscope as shown in FIG. 2. The phase shift film can exhibit a good number of growing defects upon exposure by controlling the residual ions on the surface to a predetermined concentration.

[0052] The blank mask laminate may further include a light-shielding film disposed on the phase shift film.

[0053] The light-shielding film may include a transition metal including at least one selected from the group consisting of chromium, tantalum, titanium, and hafnium, and at least one non-metallic element selected from the group consisting of oxygen, nitrogen, and carbon.

[0054] The light-shielding film may include at least one selected from the group consisting of CrO, CrON, CrOCN, and combinations thereof.

[0055] The light-shielding film may have a multi-layer structure or a two-layer structure. For example, in order to control the surface strength of the light-shielding film, the light-shielding film surface layer may be configured so that the oxygen or nitrogen content is higher on the surface side of the light-shielding film. The light-shielding film other than the light-shielding film surface layer is referred to as a light-shielding film lower layer in order to distinguish it from the light-shielding film surface layer.

[0056] The thickness of the light-shielding film surface layer may be 30 nm or more and 80 nm or less, or 40 nm or more and 70 nm or less. The thickness ratio between the light-shielding film lower layer and the light-shielding film surface layer may be 1:0.02 to 0.25, or may be 1:0.04 or more and 1:0.18 or less.

[0057] The light-shielding film may have a reflectance of about 35% or less, or about 30% or less, to a laser beam having a wavelength of 193 nm and using argon fluoride (ArF) as a light source. The reflectance may be about 20% or more, about 23% or more, or about 25% or more.

[0058] The laminate for blank masks effectively reduces sulfate ions, nitrogen oxide ions, ammonium ions, etc., thereby preventing unintended pattern transfer during the exposure process, and can be used in semi-finished and finished blank masks for forming high-quality integrated circuit patterns.

[0059] Laminate for manufacturing blank masks The laminate for manufacturing a blank mask according to the embodiment includes: a light-transmitting layer and a phase shift film disposed on the light-transmitting layer; Residual ions measured on the surface of the phase inversion membrane via ion chromatography were Concentration is 0ng / cm 2 More than 0.05ng / cm 2 sulfate ions, which are: Concentration is 0ng / cm 2 More than 2ng / cm 2 Contains at least one of the following nitrogen oxide ions: Concentration is 50ng / cm 2 More than 110ng / cm 2 containing an ammonium ion, The sum of the concentrations of sulfate ions and nitrogen oxide ions may be greater than zero.

[0060] The laminate for manufacturing a blank mask is a laminate to be used for manufacturing a blank mask, and may be manufactured through a nitrogen treatment according to an embodiment described below, and may not be subjected to a heat treatment or a cleaning treatment after the nitrogen treatment.

[0061] The light-transmitting layer of the laminate for manufacturing the blank mask is the same as that described for the laminate for the blank mask, and therefore a duplicate description will be omitted.

[0062] The composition, thickness, etc. of the phase shift film of the laminate for manufacturing the blank mask are the same as those explained in the laminate for the blank mask, so a duplicate explanation will be omitted.

[0063] The concentration of sulfate ions in the residual ions of the phase shift film is 0.001 ng / cm 2 More than 0.05ng / cm 2 It may be less than 0.001 ng / cm 2 More than 0.03ng / cm 2 It may be less than 0.001 ng / cm 2 More than 0.02ng / cm 2 or less, or 0.001 ng / cm 2 More than 0.01ng / cm 2 It may be the following:

[0064] The concentration of nitrogen oxide ions in the residual ions of the phase shift film is 0.001 ng / cm 2 More than 2ng / cm 2 It may be less than 0.001 ng / cm 2 More than 1ng / cm 2 It may be less than 0.001 ng / cm 2 More than 0.5ng / cm 2 or less, or 0.001 ng / cm2 More than 0.3ng / cm 2 It may be the following:

[0065] The concentration of the nitrogen oxide ions is specifically determined by the concentration of nitrite ions (NO2 - ) concentration is 0ng / cm 2 More than 0.3ng / cm 2 It may be nitrate ions (NO3 - ) concentration is 0ng / cm 2 More than 1ng / cm 2 or nitrite ions (NO2 - ) concentration is 0.001ng / cm 2 More than 0.1ng / cm 2 It may be nitrate ions (NO3 - ) concentration is 0.001ng / cm 2 More than 0.3ng / cm 2 It may be the following:

[0066] The concentration of ammonium ions in the residual ions of the phase shift film is 50 ng / cm 2 More than 110ng / cm 2 or less, or 60 ng / cm 2 More than 100ng / cm 2 It may be the following:

[0067] The residual ions in the phase shift film are chloride ions (Cl - ) to 0.001ng / cm 2 More than 0.05ng / cm 2 or 0.001 ng / cm 2 More than 0.03ng / cm 2 It may be included in the following concentrations:

[0068] The phase shift layer may be substantially free of ions that cause growth defects through a specific nitrogen treatment, etc., as described below, during deposition. The phase shift layer may have such a concentration of residual ions that can be further reduced through subsequent heat treatment and cleaning, and when used in a photomask, may effectively suppress the occurrence of growth defects during an exposure process.

[0069] Method for manufacturing laminate for blank mask A method for manufacturing a laminate for a blank mask according to an embodiment includes: a film-forming step of forming a phase shift film on the light-transmitting layer; a heat treatment step of heat treating the phase shift film; and a cleaning step of cleaning the heat-treated phase shift film. In the film forming step, a gas is introduced into a nitrogen atmosphere of 30% by volume or more and 70% by volume or less, and the concentration of ammonium ions on the surface of the film to be formed is 50 ng / cm 2 More than 110ng / cm 2 The nitrogen treatment process includes: The cleaning step includes a first cleaning process of applying ultraviolet light and ozone water to the heat-treated phase shift film, and a second cleaning process of applying carbonated water and hydrogen water to the phase shift film after the first cleaning process. The residual ions measured on the surface of the phase shift film after the washing step were: Concentration is 0ng / cm 2 More than 0.05ng / cm 2 Sulfate ions, which are: Concentration is 0ng / cm 2 More than 0.5ng / cm 2 Nitrogen oxide ions, which are: Concentration is 0ng / cm 2 More than 5ng / cm 2 At least one of the following ammonium ions is included: The sum of the concentrations of the residual ions may be greater than zero.

[0070] The deposition step may be performed by disposing a target containing molybdenum and silicon and sputtering it under a reactive gas atmosphere, where the reactive gas may include one or more selected from the group consisting of oxygen, nitrogen, and carbon. Exemplarily, the sputtering may be DC magnetron sputtering or RF sputtering.

[0071] The sputtering in the film formation step can be performed by the following process: i) placing a target and a support (light-transmitting layer) in a chamber, injecting atmospheric gas into the chamber, ii) applying power to the sputtering equipment, and iii) forming a film on the support with transition metal particles detached from the target together with oxygen, nitrogen, or carbon contained in the reactive gas.

[0072] In the sputtering step, target particles may be released by a sputtering gas, which is a gas that is ionized in a plasma atmosphere and collides with the target. For example, the sputtering gas may be argon (Ar) gas.

[0073] The reactive gas in the film forming step may be nitrogen, oxygen, carbon monoxide, carbon dioxide, nitrous oxide, nitric oxide, nitrogen dioxide, ammonia, methane, etc., and may include, for example, nitrogen and oxygen.

[0074] In the sputtering of the film formation step, the vacuum level in the chamber was 10 -1 Pa or more 10 -4 At such a vacuum level, the acceleration energy of the sputtered particles can be appropriately adjusted, and the stability of the film formation can be ensured.

[0075] In the sputtering of the film formation step, the flow rate of the sputtering gas may be 5 sccm to 100 sccm, 50 sccm or less, or 20 sccm or less. The flow rate of the reactive gas may be 5 sccm to 200 sccm, or 150 sccm or less. Exemplarily, the flow rate of nitrogen (N2) gas in the reactive gas may be 10 sccm to 120 sccm, or 30 sccm to 90 sccm. Helium gas, although not reactive, may be included as part of the reactive gas, and the flow rate of the helium gas may be 10 sccm to 100 sccm, or 20 sccm to 60 sccm.

[0076] In the sputtering of the film-forming step, the ratio of nitrogen in the reactive gas may be 30% by volume or more and 70% by volume or less, or 50% by volume or more and 70% by volume or less.

[0077] During the sputtering step of the deposition step, the nitrogen treatment process promotes a reaction with hydrogen (H2) in the chamber during deposition, thereby intentionally ensuring a predetermined concentration of ammonium ions on the surface of the film being deposited. The process of producing nitrogen oxides through the reaction of oxygen gas, which may be included as a reactive gas, with nitrogen gas is a non-spontaneous endothermic reaction, while the process of producing ammonium ions through the reaction of nitrogen gas with hydrogen is a spontaneous exothermic reaction. In a closed system such as a chamber, nitrogen gas may preferentially react with hydrogen. This hydrogen may remain after cleaning the light-transmitting layer, and the light-transmitting layer may be subjected to a separate hydrogen water treatment to ensure that a predetermined amount of hydrogen is present to maintain the ammonium ion concentration.

[0078] The film formation step temporarily increases the concentration of ammonium ions to 50 ng / cm through nitrogen treatment under these conditions. 2 More than 110ng / cm 2The nitrogen treatment is carried out so that the concentration of the ammonium ion is adjusted to 60 ng / cm or less, and residual sulfate ions, nitrogen oxide ions, etc. can be easily reduced in subsequent steps. 2 More than 100ng / cm 2 In the sputtering of the film forming step, the composition ratio of the target may be 5 at% to 20 at% Mo, 70 at% to 97 at% Si, and may contain 50 ppm to 230 ppm carbon and 400 ppm to 800 ppm oxygen.

[0079] The power applied to the sputtering in the film forming step may be 0.1 kW or more and 4 kW or less.

[0080] The heat treatment step may be carried out at a temperature of 300° C. to 500° C. for a period of 10 minutes to 120 minutes.

[0081] The heat treatment step may include a process of cooling the heat treatment at a temperature of 20° C. to 30° C. for 10 minutes to 60 minutes.

[0082] The heat treatment step can effectively reduce ammonium ions and nitrogen oxide ions.

[0083] The cleaning step may include a first cleaning process of applying ultraviolet light and ozone water to the phase shift film that has undergone the heat treatment step, and a second cleaning process of applying carbonated water and hydrogen water to the phase shift film that has undergone the first cleaning process.

[0084] The ultraviolet light in the first cleaning process of the cleaning step has a wavelength of 100 nm or more and 250 nm or less, and is 10 mW / cm 2 More than 100mW / cm 2 or less, for a period of 20 seconds or more and 160 seconds or less, or 20 mW / cm 2 More than 80mW / cm 2 The light may be irradiated for 30 seconds or more and 140 seconds or less at the following intensity:

[0085] The ultraviolet irradiation in the first cleaning process of the cleaning step may be performed in an atmosphere with an oxygen to nitrogen flow ratio of 1:1 or more and 1:10 or less, at a temperature of 15°C to 35°C, and at an exhaust pressure of 0.1 kPa or more and 0.75 kPa or less.

[0086] The first cleaning step of the cleaning step may be performed by adding ozone water to the phase shift film, and the ozone water may be a mixture of ozone and ultrapure water.

[0087] The concentration of the ozone water in the first cleaning process of the cleaning step may be 48 ppm or more and 155 ppm or less, or 77 ppm or more and 124 ppm or less, based on the volume.

[0088] In the first cleaning process of the cleaning step, the ultraviolet treatment and the ozone water treatment may be performed simultaneously, or may be performed in the order of ultraviolet light-ozone water or ozone water-ultraviolet light.

[0089] In the first cleaning process of the cleaning step, the ultraviolet treatment may be performed using a plurality of ultraviolet lamps, and the ozone water treatment may be performed using a plurality of ozone water supply nozzles. Exemplarily, the number of the ultraviolet lamps may be 2 to 10, and the number of the nozzles may be 2 to 10.

[0090] In the second cleaning process of the cleaning step, the carbonated water may be a mixture of carbon dioxide and ultrapure water, and the hydrogen water may be a mixture of hydrogen molecules and ultrapure water.

[0091] In the second cleaning process of the cleaning step, the electrical conductivity of the carbonated water may be 2 μS / cm or more and 10 μS / cm or less, or 2 μS / cm or more and 8 μS / cm or less. Also, in the second cleaning process of the cleaning step, the concentration of the hydrogen water may be 0.5 ppm or more and 3 ppm or less, or 0.8 ppm or more and 2.4 ppm or less, based on volume.

[0092] The second washing step of the washing step may be performed by treating carbonated water-hydrogen water or hydrogen water-carbonated water in that order, or may be performed by treating with a mixture of carbonated water and hydrogen water.

[0093] The second cleaning process of the cleaning step may also include a megasonic treatment in addition to the carbonated water and hydrogen water treatment, and may be performed at an output of 2 W to 15 W and a frequency of 0.2 MHz to 3 MHz.

[0094] The cleaning step may include a third cleaning process of adding hydrogen water to the phase shift film after the second cleaning process.

[0095] In the third cleaning process of the cleaning step, the concentration of the hydrogen water may be 0.5 ppm or more and 3 ppm or less, or 0.8 ppm or more and 2.4 ppm or less, based on the volume.

[0096] The third cleaning process of the cleaning step may include a megasonic treatment together with the hydrogen water treatment, and may be performed at an output of 5 W to 20 W and a frequency of 0.2 MHz to 3 MHz.

[0097] The washing step may include a fourth washing step in which carbonated water is added again to the phase shift film after the third washing step and the film is dried.

[0098] In the fourth cleaning process of the cleaning step, the electrical conductivity of the carbonated water may be 2 μS / cm or more and 10 μS / cm or less, or 2 μS / cm or more and 8 μS / cm or less.

[0099] In the fourth cleaning step of the cleaning step, drying may be performed using a ramp-up method in which the blank mask laminate is placed and fixed on a rotating means in an inert atmosphere and the rotation speed is increased to a target value. The rotation speed may be gradually increased from an initial speed of 30 to 100 rpm to a speed of 1000 to 1800 rpm. The phase shifter film that has undergone the cleaning step may have a reduction rate of nitrogen oxide ions of 50% to 98% or 70% to 99% according to the following formula 1 compared to the phase shifter film that has undergone the deposition step. Here, the reduction rate of ions is expressed in weight units.

[0100] [Formula 1] Reduction rate (%) = {(content of nitrogen oxide ions after film formation step - content of nitrogen oxide ions after cleaning step) / (content of nitrogen oxide ions after the film formation step)} × 100%

[0101] The content of residual ions in the phase shifter after the cleaning step is the same as that described for the blank mask laminate, and therefore, a redundant description will be omitted.

[0102] The cleaning step can be carried out substantially free of sulfuric acid or aqueous ammonia, thereby preventing chemical residues from sulfuric acid or aqueous ammonia from remaining on the surface of the phase shift film.

[0103] The method for manufacturing the laminate for a blank mask may further include a back surface cleaning step of cleaning a back surface, which is one surface of the light transmitting layer on which the phase shift film is to be formed, before the phase shift film is formed.

[0104] The rear cleaning step may include a first rear cleaning process of applying ultraviolet light and ozone water to the rear surface, a second rear cleaning process of applying SC-1 solution and ozone water to the rear surface after the first rear cleaning process, and a third rear cleaning process of applying carbonated water to the rear surface after the second rear cleaning process.

[0105] The ultraviolet light in the first post-cleaning step of the post-cleaning step has a wavelength of 100 nm or more and 250 nm or less, and is 10 mW / cm 2 More than 100mW / cm 2 or less, for a period of 20 seconds or more and 160 seconds or less, or 20 mW / cm 2 More than 80mW / cm 2 The light may be irradiated for 30 seconds or more and 140 seconds or less at the following intensity:

[0106] The ultraviolet irradiation in the first post-cleaning process of the post-cleaning step may be performed in an atmosphere with an oxygen to nitrogen flow ratio of 1:1 or more and 1:10 or less, at a temperature of 15°C to 35°C, and at an exhaust pressure of 0.1 kPa or more and 0.75 kPa or less.

[0107] The first rear surface cleaning process of the rear surface cleaning step may be performed by adding ozone water to the rear surface, and the ozone water may be a mixture of ozone and ultrapure water.

[0108] The concentration of ozone water in the first post-cleaning step of the post-cleaning step may be 48 ppm or more and 155 ppm or less, or 77 ppm or more and 124 ppm or less, based on volume.

[0109] In the first post-cleaning process of the post-cleaning step, the ultraviolet treatment and the ozone water treatment may be performed simultaneously, or may be performed in the order of ultraviolet-ozone water or ozone water-ultraviolet.

[0110] In the first post-cleaning process of the post-cleaning step, the ultraviolet treatment may be performed using a plurality of ultraviolet lamps, and for example, the number of the ultraviolet lamps may be 2 to 10.

[0111] The SC-1 (Standard Clean-1) solution in the second post-surface cleaning process of the post-surface cleaning step may be one of the standard cleaning solutions from RCA Laboratories, and may contain ammonia and hydrogen peroxide in a volume ratio of 1:0.2 to 1:1.4, and deionized water at 99% to 99.9% of the total volume.

[0112] The concentration of the ozone water in the second post-cleaning process of the post-cleaning step may be 48 ppm or more and 155 ppm or less, or 77 ppm or more and 124 ppm or less, based on volume.

[0113] In the second rear cleaning process of the rear cleaning step, the SC-1 solution treatment and the ozone water treatment may be performed simultaneously, or may be performed in the order of SC-1 solution-ozone water or ozone water-SC-1 solution. When the SC-1 solution treatment and the ozone water treatment are performed simultaneously, they may be performed through a plurality of nozzles, and for example, the number of the nozzles may be 2 to 10.

[0114] The second post-cleaning process of the post-cleaning step may also include a megasonic treatment in addition to the SC-1 solution and ozone water treatment, and may be performed at an output of 10 W to 80 W and a frequency of 0.5 MHz to 5 MHz.

[0115] The electrical conductivity of the carbonated water in the third post-cleaning step of the post-cleaning step may be 2 μS / cm or more and 10 μS / cm or less, or 2 μS / cm or more and 8 μS / cm or less.

[0116] The rear surface cleaning step may include a drying process for drying the rear surface after the third rear surface cleaning process, and may be performed using a ramp-up method in which the blank mask laminate is placed and fixed on a rotating means in an inert atmosphere, and the rotation speed is increased to a target value. The rotation speed may be gradually increased from an initial speed of 30 rpm to 100 rpm to a speed of 1000 rpm to 1800 rpm.

[0117] The present invention will be described in more detail with reference to the following specific examples. The following examples are merely illustrative examples to aid in understanding the present invention, and are not intended to limit the scope of the present invention.

[0118] Example 1-A: Formation of a phase shift film including nitrogen treatment A DC magnetron sputtering system was used to deposit a sample with a cross-sectional area of ​​504 cm 2 A 0.25 inch thick quartz glass light-transmitting layer and a target with a composition ratio of Mo of 10.75 at% and Si of 89.25 at% were placed. The angle between the light-transmitting layer and the target was 30° to 50°, and the distance between them was 255 mm.

[0119] A power of 2 kW was applied, and gas was introduced to rotate the light-transmitting layer, and film formation was performed by sputtering. During film formation, nitrogen (N2) gas and argon gas were introduced to maintain a residual volume of 70% by volume, and the ammonium concentration on the surface was kept at 50 ng / cm. 2 ~110ng / cm 2 A blank mask laminate including a phase shift film was prepared by processing the mask so that the thickness of the blank mask laminate was 100 μm.

[0120] Example 1-B: Heat treatment of phase shift film The blank mask laminate prepared in Example 1-A was subjected to a heat treatment at a temperature of 400° C. for 40 minutes, and then to a cooling treatment at 25° C. for 40 minutes.

[0121] <Example 1-C> Cleaning of phase inversion film The blank mask laminate prepared in Example 1-B was irradiated with 172 nm ultraviolet light at 40 mW / cm under uniform conditions at a temperature of 23°C in an atmosphere with an oxygen:nitrogen flow rate of 1:5. 2 At the same time, ozone water having a concentration of 100 ppm by volume was added for cleaning, so that contaminants could be easily removed in the subsequent process.

[0122] Next, carbonated water with an electrical conductivity of 4.5 μS / cm and hydrogen water with a hydrogen concentration of 1.25 ppm based on volume were added in a volume ratio of 1:1, and high frequency waves of 6.5 W and 1 MHz were also applied at the same time to perform the cleaning process.

[0123] Next, hydrogen water having a concentration of 1.25 ppm based on volume was added, and a high frequency of 10 W and 1 MHz was also applied at the same time to carry out a cleaning treatment.

[0124] Next, carbonated water having an electrical conductivity of 4.5 μS / cm was added, and the rotation speed of the rotating means on which the blank mask laminate was placed was gradually increased to dry it.

[0125] <Comparative Example 1-A> Formation of a phase shift film without nitrogen treatment In Example 1-A, the nitrogen partial pressure was reduced to less than 30% by volume so that the ammonium concentration on the surface was not maintained, and a blank mask laminate including a phase shift film was provided.

[0126] Comparative Example 1-B: Heat treatment of phase shift film The laminate produced in Comparative Example 1-A was heat-treated under the same conditions as in Example 1-B.

[0127] <Comparative Example 1-C> Cleaning of phase inversion film The laminate heat-treated in Comparative Example 1-B was washed under the same conditions as in Example 1-C.

[0128] <Experimental example - Ion chromatography analysis> For the blank mask laminate samples obtained in Examples 1A to 1C and Comparative Example 1A to 1C, ion chromatography analysis of the phase shift film surface was performed using a ThermoScientific Dionex ICS-2100 Ion Chromatography model as follows.

[0129] First, each blank mask laminate was placed in a clean bag, and then 100 mL of ultrapure water was poured into the clean bag. The clean bag was immersed in a water bath at 90°C for 120 minutes, and then an ion leaching solution was obtained from the clean bag. Then, the ion leaching solution and the eluent were poured into an ion chromatography column, and the mass of each ion was measured by ion chromatography. The measured ion content was calculated based on the surface area (504 cm) of the substrate. 2 ) to calculate the content of each ion.

[0130] During the ion chromatography measurement, a solution containing KOH, LiOH, MSA (methanesulfonic acid), and NaOH was used as the eluent, and the mobile phase flow rate was 0.4 mL / min to 2.0 mL / min.

[0131] The residual ion contents measured by ion chromatography for each of the Examples and Comparative Examples are shown in Table 1 below.

[0132] JPEG0007743572000001.jpg96164 Unit: ng / cm 2 In all examples and comparative examples, F, acetate, formate, PO4, oxalate, Na, K, Mg, and Ca ions were not detected.

[0133] Referring to Table 1, Examples 1-A, 1-B, and 1-C, which were subjected to nitrogen treatment, showed NO x The sum of the ions is approximately 0.5ng / cm 2 The comparison examples without nitrogen treatment were all reduced to NO x The sum of the ions is approximately 6ng / cm 2 It was confirmed that the concentrations of sulfate ions and chloride ions were also lower in the Examples than in the Comparative Examples.

[0134] This is believed to be due to the fact that the specific nitrogen treatment carried out in the example maintained the concentration of ammonium ions on the surface at a predetermined concentration while suppressing the generation of nitrogen oxide ions, etc. In Example 1-C, in which the entire process from film formation to heat treatment and cleaning was carried out, it was confirmed that ammonium ions, nitrogen oxide ions, sulfate ions, and chloride ions, which cause growth defects, were all effectively reduced.

[0135] <Experimental Example - Measurement of Growth Defects> An intaglio pattern was formed on the surface of the phase shift film of the blank mask laminate samples obtained in Example 1-C and Comparative Example 1-C by conventional etching, partially exposing the light-transmitting layer. The surface of the phase shift film of each sample was then irradiated with 193 nm light from a UV particle accelerator for 120 minutes at 23°C and 45% relative humidity, resulting in a cumulative exposure energy of 10 kJ. The surface of each sample was then photographed using a scanning electron microscope (SEM). The photographs for Comparative Example 1-C and Example 1-C are shown in Figure 1 and Figure 2, respectively.

[0136] Referring to Figure 1, in the case of Comparative Example 1-C, in which nitrogen oxide ions and sulfur oxide ions remained at a certain concentration on the surface of the phase shift film, it was confirmed that a large number of black spots of 50 nm or less, which are growth defects, appeared after exposure.

[0137] Referring to FIG. 2, it was confirmed that in Example 1-C, in which the concentrations of nitrogen oxide ions and sulfur oxide ions were significantly suppressed, no growing defects were observed after exposure.

[0138] Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the appended claims also fall within the scope of the present invention. [Explanation of symbols]

[0139] MoSi Phase shift film containing Mo and Si Q'z Quartz glass (silica glass) light-transmitting layer Haze Factors that cause haze, growth defects

Claims

1. a film-forming step of forming a phase shift film on the light-transmitting layer; a heat treatment step of heat treating the phase shift film; and a cleaning step of cleaning the heat-treated phase shift film. In the film forming step, a gas is introduced into a nitrogen atmosphere of 30% by volume or more and 70% by volume or less, and the concentration of ammonium ions on the surface of the film to be formed is 50 ng / cm ２ More than 110ng / cm ２ The nitrogen treatment process includes: The cleaning step includes a first cleaning process of applying ultraviolet light and ozone water to the heat-treated phase shift film, and a second cleaning process of applying carbonated water and hydrogen water to the phase shift film after the first cleaning process, The residual ions measured on the surface of the phase shift film after the washing step were: Concentration is 0 ng / cm ２ 0.5ng / cm or more ２ containing nitrogen oxide ions, which are: The residual ions further include chloride ions (Cl-), The concentration of the chloride ions is 0.05 ng / cm ２ is as follows: The method for manufacturing a laminate for a blank mask, wherein the sum of the concentrations of the residual ions exceeds zero.

2. The film forming step includes: A target containing molybdenum and silicon is placed, and sputtering is performed in a reactive gas atmosphere. The method for manufacturing a laminate for a blank mask according to claim 1 , wherein the reactive gas includes at least one selected from the group consisting of oxygen, nitrogen, and carbon.

3. In the first cleaning process of the cleaning step, the ultraviolet light has a wavelength of 100 nm or more and 250 nm or less and an intensity of 10 mW / cm ２ 100mW / cm or more ２ The method for manufacturing a laminate for a blank mask according to claim 1 , wherein the laminate is irradiated with:

4. The washing step comprises: a third cleaning step of adding hydrogen water to the phase shift film after the second cleaning step; and 2. The method of claim 1, further comprising a fourth cleaning step of adding carbonated water to the phase shift film after the third cleaning step and drying the film.

5. a light-transmitting layer and a phase shift film disposed on the light-transmitting layer; Residual ions measured on the surface of the phase inversion membrane via ion chromatography were Concentration is 0 ng / cm ２ 2ng / cm or more ２ containing nitrogen oxide ions, which are: Concentration is 50ng / cm ２ More than 110ng / cm ２ containing an ammonium ion, The residual ions are chloride ions (Cl － ) further comprising The concentration of the chloride ions is 0.05 ng / cm ２ is as follows: A laminate for manufacturing a blank mask, wherein the sum of the concentrations of sulfate ions and nitrogen oxide ions exceeds zero.

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