KR100890409B1 - Half-tone phase shift blankmask, half-tone phase shift photomask and it's manufacturing method - Google Patents

Abstract

A half-tone phase shift blank mask is provided to maintain thin film property for a long time and to form a phase shift film having critical dimension of high quality. A half-tone phase shift blank mask is formed with one or more films selected from a phase shift film(2), light-shielding film, anti-reflective film and resist film on a transparent substrate(1). The phase shift film is formed from a sputtering target having the thickness of 2~7 mm and is used for a KrF lithography using the wavelength of 248 nm. The phase shift film comprises molybdenum 7~15 at%, silicon 55~63 at% and nitrogen 28~35 at%.

Description

Half-tone phase shift blank mask, half-tone phase shift blank mask, half-tone phase shift photomask and it's manufacturing method

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a halftone phase inversion blank mask and a halftone phase inversion photomask capable of implementing a high precision critical dimension (CD) in a semiconductor photo-lithography process. In particular, KrF lithography of 248 nm, The present invention relates to a halftone phase inversion blank mask and a halftone phase inversion photomask applicable to ArF lithography and immersion lithography of 193 nm.

Due to the high integration of semiconductor integrated circuits, the importance of photo-lithography technology, which is a core process of semiconductor manufacturers, is increasing. Such photolithography technology has shortened the exposure wavelength to 436 nm g-line, 365 nm i-line, 248 nm KrF, 193 nm ArF, etc. to improve the resolution of semiconductor circuit patterns. However, the shortening of the exposure wavelength greatly contributes to the improvement of the resolution, but has a bad effect on the depth of focus (DoF), causing a lot of burden on the design of the optical system including the lens.

Accordingly, in order to solve the above problems, a phase inversion mask has been developed that simultaneously improves the resolution and the depth of focus by modifying the phase of the exposure light passing through the transmission part by using the phase inversion film as the transflective portion.

The phase inversion mask includes a reversal phase inversion mask and a halftone phase inversion mask, and the halftone phase inversion mask has a single layer of molybdenum silicide (MoSi) -based MoSiN, to facilitate process control and CD control. MoSiCN, MoSiO, MoSiON, MoSiCON Halftone phase inverted blank mask is currently used to apply the half-tone phase inversion film.

In general, the phase inversion film is formed on a transparent substrate mainly composed of quartz through DC reactive sputtering. However, the conventional MoSiN phase inversion film has a problem of deviating from the target transmittance over time in the target transmittance of the phase inversion film after forming the phase inversion film due to a mismatch in composition. In the composition of MoSiN phase inversion film formed by sputtering, the free energy of the thin film is formed in a high state due to a mismatch between Mo, Si, and N, and thus the material is maintained in a thermodynamically stable state. In order to reduce the free energy, the thin film shows a phenomenon in which the transmittance is changed. As a result, various thin film characteristics such as density, fine crystallization state, residual stress, and the like also change.

In addition, in order to improve the characteristics of the thin film such as transmittance, phase inversion, reliability, exposure resistance, etc. when forming the MoSiN phase inversion film through sputtering, heat treatment may be performed during sputtering or after sputtering. However, in the case of the conventional MoSiN thin film, partial crystallization of the thin film occurs due to the unstable composition, and when the pattern is formed in halftone type phase inversion photomask manufacturing, the cross section of the pattern becomes rough due to the partial crystallization of the thin film. In the end, there is a problem that it is difficult to form a pattern having excellent characteristics.

In addition, when a halftone phase inversion photomask is manufactured by dry etching a MoSiN phase inversion film, dry etching is performed by mixing SF ₆ or CF ₄ gas containing fluorine and O ₂ gas. However, in the case of the conventional MoSiN phase inversion film, since the composition of Mo, Si, N is present in an unstable state, the sidewall angle of the pattern becomes low after dry etching, making it difficult to form a pattern having a vertical cross section, and thus having a superior photomask characteristic. It's hard to manufacture.

In addition, the introduction of immersion lithography to realize high-resolution CD of 45nm class has become important to control polarization characteristics by birefringence of phase inversion film. However, in the case of the conventional MoSiN phase inversion film, the polarity is not considered at all, thereby amplifying the influence of the TM (Transverse Magnetic) wave that adversely affects the pattern formation during the pattern process through immersion lithography and improving the resolution of the pattern. It reduces the influence of helpful TE (Transverse Electric) waves, which makes it difficult to form patterns with high resolution.

In addition, the existing MoSiN phase inversion film has an unstable composition ratio between Mo, Si, and N, and thus, due to environmental factors such as clean room, air, packing box, and pellet, Adsorption of generated airborne molecular contamination (Airborne Molecular Contamination) is well achieved. This will give sufficient activity energy to the continuous energy of exposure light during wafer printing, i.e. air molecule pollutants contained on the surface and / or inside of, for example, continuous exposure of ArF exposure light source at 193 nm. As a result, airborne chemical pollutants generate chemical reactions on the surface, resulting in growth defects. The growth defects continue to grow, resulting in a thickness, transmittance, phase shift, and defect that a predetermined phase inversion film must have, and eventually, a production yield in manufacturing a semiconductor device is deteriorated.

In addition, the phase shift film of the conventional MoSiN is damaged by the strong base and the strong acid, which are chemicals used in the lithography cleaning process, due to a mismatch between the Mo, Si, and N ratios. The phase shift amount is changed. Therefore, there is a problem that can not be used because it is out of the target phase change amount and transmittance.

In addition, in the case of a general halftone phase inversion blank mask, the structure has a structure in which a phase inversion film, a light shielding film, an antireflection film, and a resist are laminated on a transparent substrate, but such a structure has a thickness of a lower film due to the thickness of the resist of 3000 kPa to 2000 kPa. It has a considerably higher characteristic. As a result, loading effects and aspect ratios increase during dry etching, resulting in problems such as collapse of the resist and overlapping, which makes it difficult to form a precise pattern.

In addition, the conventional phase inversion film uses a transmission or reflection method as a general inspection method, and in order to improve inspection contrast, the phase inversion film transmittance at the inspection wavelength needs to be 70% or less or 40% or less. I am doing it. However, in the case of the conventional MoSiN phase inversion film, in particular, when the pattern is smaller than 65 nm to be implemented in ArF lithography, as the pattern becomes smaller, the defect size compared to the original pattern and the size difference between the line and space patterns are generated. There is a problem that the method is not completely tested.

In order to solve the above problems, in the halftone phase inversion blank mask and halftone phase inversion photomask applied to KrF at 248 nm, ArF at 193 nm, and immersion lithography, the change in transmittance through the optimization of the composition ratio is minimized, and the reflectance is Alternatively, the transmittance can be controlled, excellent sidewall slope can be obtained during dry etching, a phase inversion film having excellent amorphous properties without crystallization can be obtained, and halftone type phase inversion photo having high quality through polarity control in Immersion Lithography This is to implement a mask to manufacture a high-resolution semiconductor circuit pattern having excellent quality such as 65nm, 45nm, 32nm or less.

In addition, the present invention provides an appropriate composition ratio for reducing the growth defects, in particular, the halftone type phase inversion blank mask and halftone type phase inversion photo, which is controlled to reduce the growth defects by controlling the air molecular source through surface treatment To provide a mask.

In addition, the present invention is to provide a high-resolution semiconductor circuit pattern having excellent quality by providing a single layer or a multi-layered phase reversal film structure of more than two layers, and by providing a structure in which a hard mask is stacked to reduce a loading effect.

In the case of the halftone phase inversion blank mask manufacturing process according to the present invention,

a1) forming a phase inversion film on the transparent substrate;

b1) forming a metal film on the phase inversion film formed in step a1);

c1) forming a resist film on the metal film formed in step b1) to manufacture a halftone phase inversion blank mask.

Next, in the case of the halftone phase shift photomask manufacturing process according to the present invention using the halftone phase shift blank mask manufactured through the steps a1) to d1),

a2) exposing to a region where a pattern is to be formed on the resist film;

b2) developing using a developer to remove the resist film exposed in step a2) and to form a resist pattern;

c2) forming a metal film pattern by etching the metal film using the resist pattern formed in the step b2) as a mask;

d2) forming a phase shift film pattern by etching the phase shift film using the resist pattern and the metal film pattern formed through the steps b2) and c2) as masks;

e2) removing the resist pattern after the phase inversion film pattern is formed in step d2);

f2) forming a resist film after the resist pattern in step e2;

g2) exposing to a region desired for pattern formation after forming a resist film in step f2);

h2) exposing the resist film in step g2) and then developing to form a resist pattern;

i2) forming a metal film pattern by etching the metal film using the resist pattern formed in step h2) as a mask;

j2) forming a metal film pattern in step i2) and then removing the resist pattern to produce a halftone phase inversion photomask.

In the step a1), the phase inversion film is essentially composed of molybdenum, silicon, nitrogen, it is characterized in that it may additionally include carbon, oxygen, fluorine.

In the step a1), the phase inversion film essentially comprises molybdenum, silicon, nitrogen, characterized in that consisting of a single layer or multiple layers.

In the step a1), if the phase inversion film is suitable for KrF lithography of 248 nm, the composition of the phase inversion film is 7-15 at% of molybdenum, 55 to 63 at% of silicon, and 28 to 35 at% of nitrogen. When the phase inversion film is suitable for 193 nm ArF lithography, the composition of the phase inversion film is 5 to 10 at% of molybdenum, 55 to 65 at% of silicon, and 28 to 35 at% of nitrogen. In this case, if the composition of molybdenum, silicon, and nitrogen is out of the upper limit or the lower limit, the free energy of the thin film is increased, and thus, the sputtering may cause the problem of being out of the target transmittance over time after the thin film is formed. In addition, especially when the ratio of silicon is out of the upper limit or the lower limit, the ratio of SiN is relatively increased or decreased in part when forming the phase inversion film through sputtering, thereby causing partial crystallization of the thin film. When the ratio of SiN is lowered, MoN crystallization component is increased relatively. When the ratio of SiN is relatively high, MoN crystallized component is relatively decreased. Partial crystallization occurs due to the increase and decrease of the MoN and SiN crystallization components, and the pattern characteristics are degraded due to the partial crystallization, and thus the quality of the minimum line width is degraded. Therefore, the partial crystallization is maintained only when the molybdenum and silicon ratios are maintained. It is possible to obtain a thin film in the amorphous state that does not occur, and the amorphous thin film enables the production of a halftone type phase inversion photomask having high quality line width characteristics. In the case of nitrogen, when the upper limit or the lower limit is exceeded, proper bonding between the Radical and the MoSiN phase inversion layer is not performed during dry etching, and eventually, the volatilization of the material does not occur and re-deposition occurs. The angle or shape may be degraded.

In the step a1), when the phase inversion film is suitable for KrF lithography, in the sputtering process for forming the phase inversion film, argon of 30-40 vol%, nitrogen of 60-70 vol%, and additionally, a gas containing carbon and oxygen may be used. It is characterized in that the power density is 1 ~ 2W / cm ² , the pressure is 1x10 ^-2 ~ 1x10 ^-4 torr. If the phase inversion film is suitable for ArF lithography, argon may be 15 to 25 vol%, nitrogen is 75 to 85 vol%, and a gas containing carbon and oxygen may be used in the sputtering process for forming the phase inversion film. 2W / cm ² , the pressure is 1x10 ^-2 ~ 1x10 ^-4 torr. When sputtering is performed through the above process range, it becomes possible to manufacture a phase inversion film having excellent characteristics having amorphous characteristics. In particular, when nitrogen is out of the lower limit, sufficient nitrogen is not supplied, so the proportion of MoSi in the phase inversion film is excessively high, so that it is easy to cause partial crystallization. When nitrogen is out of the upper limit, the proportion of MoSi, which constitutes the skeleton of the phase inversion film, is decreased. As the porosity of the thin film increases, it is easily removed during dry etching, making it difficult to control the inclination (angle) of the pattern sidewall.

In the step a1), the phase inversion film further comprises a trace amount of oxygen of 5at% or less. In general, when oxygen is included in the phase inversion film, chemical resistance to sulfuric acid, ammonia, and the like is inferior. However, by containing a trace amount of oxygen of 5 at% or less, the transmittance can be freely controlled within a range that does not significantly reduce chemical resistance. At this time, in the method of including oxygen in the phase inversion film, the phase inversion film is formed using a gas containing oxygen as a reactive gas during the sputtering process, or after the phase inversion film is formed, heat treatment is performed in a gas atmosphere containing oxygen. It is possible to include oxygen in the phase inversion film. When oxygen is included by heat treatment, the oxygen content is increased on the surface of the phase inversion film and the composition of oxygen decreases toward the substrate.

In the step a1), if the phase inversion film is suitable for KrF lithography, the sputtering target for forming the phase inversion film is composed of molybdenum and silicon, and has a composition of 15-25 at% molybdenum and 75-85 at% silicon. , Characterized in that the thickness is 2 ~ 7mm. If the phase inversion film is suitable for ArF lithography, the sputtering target for forming the phase inversion film is composed of molybdenum and silicon, and has a composition of 5 to 15 at% molybdenum and 85 to 95 at% silicon, and has a thickness of 2 to 7 mm. It is characterized by that. At this time, if the thickness of the sputtering target is out of the lower limit, the sputtering target is quickly consumed due to the erosion of the sputtering target for manufacturing the phase shift film, which is inappropriate for mass production. In general, during the sputtering of the phase inversion film, a magnet is formed by rotating a magnet in an electrode part on the back of the target to form a magnetron sputtering method for controlling plasma density, uniformity, and the like. At this time, when the thickness of the target is out of the upper limit, the effect of controlling the magnetic field through the magnet is inferior. Thus, when the phase inversion film is formed, a phase inversion film having non-uniform characteristics in thickness, composition ratio, transmittance, etc. is formed, thus making it difficult to manufacture a high quality phase inversion film. Therefore, the thickness of the target should be in the range of 2-7 mm for the high quality phase inversion film and the practical sputtering target for mass production.

In the step a1), when the phase inversion film is suitable for KrF lithography, the thickness of the phase inversion film is 850 to 900 mW for phase inversion of 180 degrees. And if the phase inversion film is suitable for ArF lithography, the thickness of the phase inversion film is characterized in that 630 ~ 680Å for 180 degree phase inversion. At this time, if the upper limit and the lower limit of the thickness is out of the practical range of the phase inversion of 175 ~ 185 will not function as the phase inversion film.

In step a1), when the phase inversion film is suitable for KrF lithography, the transmittance of the phase inversion film is 4.5 to 9%. And if the phase inversion film is suitable for ArF lithography, the transmittance of the phase inversion film is characterized in that 4.5 ~ 7%.

In the step a1), the reflectance or transmittance of the phase inversion film has a transmittance of 65% or less and a reflectance of 40% or less at a wavelength of about 200 to 700 nm, which is an inspection wavelength for defects or registration inspections. As the pattern size becomes more and more fine, the conventional inspection method of transmission alone or reflection alone is not perfect. Therefore, there is an increasing need for an improved transmissive or reflective or transmissive mixed inspection mode, whereby the transmittance at an inspection wavelength of 200 to 700 nm is increased to 65% to increase the inspection sensitivity in the inspection of the halftone phase inversion film. Hereinafter, a phase inversion film having a reflectance of 40% or less is required.

In the step a1), in order to control the growth defect of the phase shift film, the surface treatment is performed by surface treatment such as a hot plate, a rapid heat treatment apparatus, a plasma treatment, and a rapid cooling apparatus. As exposure light becomes shorter and shorter at 248nm and 193nm, high exposure energy provides active energy of air molecule pollutants remaining and / or adsorbed on the halftone phase inversion mask surface, resulting in growth defects when continuous exposure energy is irradiated. There is this. Therefore, in order to control this, it is necessary to control the source of air molecules, and it is preferable to use a method such as a hot plate, a rapid heat treatment apparatus, or a plasma treatment for the surface treatment. Common air molecule pollution is classified into acid air molecule pollution, base ingredient contamination, dopant molecule pollution, and volatile molecular pollution. These pollutants include targets forming a thin film, process atmosphere, process process, and storage box. Environmental factors such as boxes, pellicles, people, etc. are adsorbed on the thin film through various paths in the manufacturing process. In order to remove the adsorbed air molecule source, the surface treatment method for decomposition and / or volatilization of the air molecule source is one method, and another method is to surface-treat the film so that the air molecule source is not adsorbed on the thin film. . Among these methods, methods such as plasma treatment can remove surface air molecular pollutants by removing organic substances such as C, H and O present on the surface. Alternatively, the adsorption of air molecular pollutants is difficult by decomposing the adsorbed air molecular pollutants and stabilizing the thin film.

In the step a1), when the phase inversion film is used for immersion lithography, the birefringence of the phase inversion film is 2 nm / phase inversion film thickness. At this time, when the birefringence of the phase inversion film exceeds 2 nm, the polarization phenomenon due to the birefringence is amplified, and the TM wave of the exposure light source is amplified during immersion lithography, and eventually the bad pattern is transferred to the final wafer when transferring the circuit to the final wafer. It is difficult to manufacture a semiconductor device having a size. The birefringence of the phase inversion film can be controlled by the composition ratio of Mo, Si, and N constituting the phase inversion film, the same structure, density, thickness, surface roughness, and degree of crystallization as in a single film or a multilayer film.

In the step b1), when the light shielding film and the antireflection film are sequentially formed in the metal film direction from the transparent substrate direction, the main components of the light shielding film and the antireflection film are chromium.

In the step b1), when the light shielding film and the antireflection film are sequentially formed from the metal film in the direction of the transparent substrate, the optical density at 193nm to 248nm of the light shielding film and the antireflection film is 2.5 to 3.5.

In the step b1), when the light shielding film and the antireflection film are sequentially formed in the metal film direction from the transparent substrate direction, the thickness of the light shielding film and the antireflection film is 300 to 1100 kPa.

In the step b1), when the light shielding film and the antireflection film containing chromium as a main component are sequentially formed from the direction of the transparent substrate, the metal film containing molybdenum silicide (MoSi) or silicon (Si) as the main component is formed on the antireflection film. It is characterized by further forming.

In the step b1), when the metal film is sequentially formed a light shielding film and an antireflection film mainly composed of chromium from the direction of the transparent substrate, and the metal film is additionally formed on the antireflection film, the additionally formed metal film is composed of MoSi as the main component and is oxidized, nitrided, Characterized in the form of a compound selected from carbonization, oxynitride, oxidative carbonization, nitride carbonization, oxynitride carbonization.

In the step b1), when the metal film is sequentially formed a light shielding film and an antireflection film containing chromium as a main component from the transparent substrate direction, and the metal film is additionally formed on the antireflection film, the additionally formed metal film is composed of Si as the main component and is oxidized, nitrided, Characterized in the form of a compound selected from carbonization, oxynitride, oxidative carbonization, nitride carbonization, oxynitride carbonization.

In the step b1), the metal film is an etching solution used to etch molybdenum silicide or silicon on the anti-reflection film when the light shielding film and the anti-reflection film composed mainly of molybdenum silicide or silicon are sequentially formed from the direction of the transparent substrate or A metal film of a material that is not etched in the etching gas is additionally formed.

In the step b1), when the metal film is formed of a light shielding film and an antireflection film containing molybdenum silicide or silicon as a main component sequentially from the direction of the transparent substrate, an etching solution used for etching molybdenum silicide or silicon under the light shielding film or A metal film of a material that is not etched in the etching gas is additionally formed.

In the step b1), when the metal film is formed of a light shielding film and an antireflection film containing molybdenum silicide or silicon as a main component sequentially from the direction of the transparent substrate, the molybdenum silicide or silicon is used under the light shielding film or on the antireflection film. The metal film of the material that is not etched in the etching solution or etching gas is characterized in that the additional formed.

In the step c1), the resist film is a chemically amplified resist and has a thickness of 4000 kPa or less.

Step a2) to j2) is characterized in that carried out by a conventional halftone phase inversion photomask manufacturing process.

Through the above process, a halftone phase inversion blank mask and a halftone phase inversion photomask according to the present invention were prepared.

According to the halftone type phase inversion blank mask and the halftone type phase inversion photomask according to the present invention, the thin film characteristics obtained when the phase inversion film is formed can be maintained for a long time, and excellent characteristics can be obtained by forming a phase inversion film that is not crystallized when forming the pattern. It is possible to form a pattern having a phase inversion film having a minimum line width characteristics of high quality, and eventually has the effect of manufacturing a high quality semiconductor circuit.

In addition, the half-tone phase inversion blank mask and the half-tone phase inversion photomask according to the present invention provide a phase inversion film having a low incidence of growth defects due to continuous exposure through surface treatment of the phase inversion film, thereby yielding It has the effect of making excellent high quality semiconductor circuit through increase and decrease of defect.

In addition, according to the half-tone phase inversion blank mask and the half-tone phase inversion photomask according to the present invention, by forming a hard mask film to reduce the loading effect, it is possible to form an excellent pattern, thereby producing a high-quality semiconductor circuit Has an effect.

Hereinafter, the present invention will be described in detail with reference to examples, but the examples are used only for the purpose of illustration and description of the present invention, and are used to limit the scope of the present invention as defined in the meaning or claims. no. Therefore, those skilled 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 be defined by the technical details of the claims.

<Example 1 and Comparative Example 1>

The first embodiment is an example in which a halftone phase inversion blank mask on which a phase inversion film is formed is manufactured.

First, a phase inversion film 2 including a MoSiN component was formed on a transparent substrate 1 having a size of 6025 with reference to FIG. 1. At this time, the phase inversion film was formed through a sputtering target having a composition of 10:90 at% of Mo: Si and 20:80 at% of Mo: Si using DC magnetron sputtering equipment, and the thickness of the sputtering target was the same. It is 6mm. In addition, a backing plate made of high purity copper having a thickness of 6 mm is a target bonded using indium (In). In the case of Comparative Example 1, sputtering was performed using the same conditions through sputtering having a thickness of 8 mm. At this time, Mo: Si = 10: 90at% target is argon 20sccm, nitrogen is 80sccm, power density is 1.5W / cm ² , pressure is 1.5mtorr, and Mo: Si = 20: 80at% target is argon 34 sccm, nitrogen, 61sccm, power density was applied 1.8W / cm ² , 2mtorr. In the sputtering process, the heat treatment temperature of the substrate was 200 ° C for Mo: Si = 10: 90at%, and 180 ° C for Mo: Si = 20: 80at%.

In the case of Mo: Si = 10: 90at% of the phase inversion film formed through the above example, an average transmittance of 5.8% and an average phase inversion of 177 degrees were measured at an ArF wavelength of 193 nm, and an average thickness of 648 Å was measured. In addition, the difference between the maximum and minimum values of the transmittance, phase reversal, and thickness distribution ranges obtained by measuring a total of 49 areas in the 142mmx142mm area, which is the actual effective area of the 6025 substrate, was excellent at 0.08%, 0.9 °, and 6Å, respectively. For Mo: Si = 20: 80at%, average transmittance of 5.7% and average phase inversion film of 177 ° were measured at KrF wavelength of 248nm, and average thickness of 853Å was measured. Similarly, the maximum and minimum values of the transmittance, phase inversion, and thickness distribution ranges were 0.07%, 0.8 degrees, and 5 dB in 49 areas in the 142 mm x 142 mm area, which is the actual effective area of the 6025 substrate.

On the other hand, in the Mo: Si = 10: 90at% ArF phase inversion film formed through the comparative example, an average transmittance of 5.75% and an average phase inversion of 177 degrees were measured, and an average thickness of 652Å was measured, but the difference between the maximum and minimum values was transmittance and phase. Very low quality phase inversion films were formed with inversion and thickness of 0.34%, 3.6 degrees, and 28 Hz respectively. Similarly, Mo: Si = 20: 80at% phase inversion films for KrF also had an average transmittance of 5.73% and an average phase of 178 degrees. The average thickness of the inverted film and 855 Å was measured, but a very poor quality phase inversion film was formed at 0.38%, 3.2 degrees, and 25 차이 between the maximum and minimum values. This is because the magnetic field generated by the magnet of the Cathode portion due to the thickness of the sputtering target is difficult to efficiently control the plasma distribution and density. Judging. Through the above embodiment it was possible to manufacture a phase inversion film having excellent quality.

<Example 2 and Comparative Example 2>

The second embodiment is an example in which a halftone phase inversion blank mask on which a phase inversion film is formed is manufactured.

First, a phase inversion film having a composition of MoSiN was formed on a transparent substrate. At this time, the phase inversion film was formed through DC magnetron sputtering, and a sputtering target having a composition of Mo: Si of 10:90 at% and a thickness of 6 mm was used. In this case, as for the sputtering gas, 20 sccm of argon, 80 sccm of nitrogen, 1.5 W / cm ^{2 of} power density, and 1.5 mtorr of pressure were applied. In addition, the heat treatment temperature of the substrate during sputtering was applied to 200 ℃. At this time, Comparative Example 2 was also sputtered for comparison. At this time, 10 sccm of argon, 90 sccm of nitrogen, and 1.7 W / cm ² of power density were used, and the same conditions as in Example 2 were applied. It became.

The phase inversion film formed through Example 2 had a good thickness of 649 kV, transmittance of 5.95%, and phase inversion of 177 degrees. In the case of the phase inversion film formed through Comparative Example 2, the thickness was measured at 925 두께, transmittance of 6.01%, and 181 degrees. As a result of observing the composition ratio through Auger analysis on the phase inversion film formed through the above Example 2 and Comparative Example 2, in Example 2, the ratio of Mo: Si: N is 5:58:37 at% In the case of 2, the composition ratio of 7:45:48 at% was analyzed. In addition, as a result of analyzing the crystallization state through the XRD for the phase inversion film, in the case of Example 2 was analyzed as an amorphous (amorphous) state, in the case of Comparative Example 2 was observed a weak MoN and SiN crystallization but not complete crystallization.

In addition, in order to examine the stabilization of the thin film, in Example 2 and Comparative Example 2, the change in transmittance was measured every day for a period of 10 days. First, in Example 2, the total transmittance of 0.05% was increased only for 10 days, but in Comparative Example 2, an increase in total transmittance of 0.30% was observed. This results in a case of Comparative Example 2, which is outside the transmittance range of 5.9 to 6.1%, which is generally acceptable, and eventually becomes defective. On the other hand, in the case of Example 2, the transmittance characteristic did not change even after 10 days, and thus, it was confirmed that the phase inversion film of the superior quality having the production margin was relatively higher than that of Comparative Example 2. This is because phase inversion film formation should form stable thin film with low free energy through proper combination of Mo, Si, and N. However, in the case of 2, the ionization energy of each film is high due to the similar ratio of silicon and nitrogen. As the free energy increases, the transmittance is increased due to the thermodynamic characteristic that the thin film is unstable and tries to move to the low free energy after the phase inversion film is formed. Also, the relatively high energy promotes oxidation of the phase inversion film, thereby increasing the transmittance. .

Next, in Example 2 and Comparative Example 2, the same pattern of the light shielding film, the antireflection film, and the resist film was formed, followed by fabrication of a 65 nm-class photomask, and the pattern minimum line width uniformity was measured. Was measured, but in Comparative Example 2 showed a very poor result with a minimum line uniformity of 18.7 nm. For the cause analysis, the slope of the sidewall of the pattern was observed by SEM measurement, and the fidelity of the pattern was observed by SEM. First, in Example 2, the inclination of the pattern sidewall was very good at 87 degrees, indicating an excellent pattern inclination, but in Comparative Example 2, the inclination of the pattern sidewall was inferior in 78 degrees. In addition, as a result of pattern fidelity observation, in Example 2, the pattern formation was very smooth, whereas in Comparative Example 2, it was confirmed that the side of the pattern was formed unevenly. In Example 2, since the ratio of Mo, Si, and N was optimized, the crystallization in the thin film did not occur. However, in Comparative Example 2, the pattern was formed due to partial crystallization of MoN and SiN. Due to the poor characteristics, the minimum line width uniformity is considered to be poor. Due to such a pattern defect, it becomes difficult to manufacture a halftone type phase inversion photomask having high quality, and eventually becomes an inadequate photomask for a 65nm class.

<Example 3 and Comparative Example 3>

This third embodiment is an example in which a halftone phase inversion blank mask is formed in which a phase inversion film suitable for KrF lithography is formed in the same manner as in Example 2 and Comparative Example 2.

As in Example 2, a phase inversion film having a composition of MoSiN was formed on a transparent substrate. At this time, a target having a composition of 20:80 at% of Mo: Si and a thickness of 5 mm was used. In this case, the sputtering gas was 34 sccm of argon, 61 sccm of nitrogen, 1.8 W / cm ^{2 of} power density, and ² mtorr of pressure. In addition, the heat treatment temperature of the substrate during sputtering was applied to 180 ℃. At this time, Comparative Example 3 was also sputtered for comparison, 20 sccm of argon, 80 sccm of nitrogen, 1.5 W / cm ² of power density were applied, and the same conditions as in Example 2 were applied to all remaining conditions not mentioned.

The phase inversion film formed through Example 3 had a thickness of 855 Å, a transmittance of 5.73%, and a phase inversion of 178 degrees. In the case of the phase inversion film formed through Comparative Example 3, the phase inversion of the transmittance was 6.08% and 172 degrees at 848nm and 248nm. As a result of observing the composition ratio through the Auger analysis of the phase inversion film for KrF formed through Example 3 and Comparative Example 3, in the case of Example 3, the ratio Mo: Si: N is 10:58:32 at% In the case of Comparative Example 3, the composition ratio of 10:45:45 at% was analyzed. In addition, as a result of analyzing the crystallization state through the XRD for the phase inversion film, in the case of Example 3 was analyzed as an amorphous (amorphous) state, Comparative Example 3 is not completely crystallization, but the same weak as the ArF phase inversion film MoN and SiN crystallizations were observed.

In order to examine the stabilization of the thin film in the same manner, in Example 3 and Comparative Example 3, the change in transmittance was measured every day for a period of 10 days. First, in Example 3, a total transmittance of 0.04% was increased only for 10 days, but in Comparative Example 3, an increase in transmittance of 0.25% was observed. This resulted in the case of Comparative Example 3 is out of the transmittance range of 5.9 ~ 6.1% which is generally acceptable transmittance.

Next, in Example 3 and Comparative Example 3, a light shielding film, an antireflection film, and a resist film were formed in the same manner, and then a 90 nm photomask was manufactured to observe the inclination of the sidewall of the pattern through SEM, and the fidelity of the pattern through the SEM. ) Was observed. First, in Example 3, the inclination of the pattern sidewall was very good at 88 degrees, indicating an excellent pattern inclination, but in Comparative Example 3, the inclination of the pattern sidewall was inferior in 75 degrees. In addition, as a result of pattern fidelity observation, in Example 3, the pattern formation was very smooth, whereas in Comparative Example 3, it was confirmed that the side surface of the pattern was unevenly formed.

<Example 4 and Comparative Examples 4 and 5>

Next, we analyzed the main sources of air molecular pollutants to control growth defects. First, an ArF phase inversion film was deposited on a 6025 transparent substrate using a sputtering target having a composition of Mo: Si = 10: 90 at%. At this time, the sputtering conditions were carried out under the condition of having a thickness of about 650 kPa using 20 sccm of Ar and 80 sccm of N2. Then, for Comparative Examples 4 and 5, a phase inversion film for ArF was deposited using a sputtering target having a composition ratio of MoSi = 4: 96at% and MoSi = 16: 84at%. At this time, the sputtering conditions of Comparative Example 4 was carried out under the condition of having a thickness of about 700 μs using 30 sccm of Ar and 70 sccm of N2. In Comparative Example 5, the thickness of about 925 mm using 10 sccm of N and 90 sccm of N2. The process was carried out under the conditions having. At this time, the composition ratios of the thin films of Example 4, Comparative Examples 4, 5 were 10: 60: 30at%, 8: 64: 28at%, 7: 45: 48at% of composition ratio of Mo: Si: N through Auger analysis, respectively. Was analyzed.

Next, each phase inversion film was treated with Standard Cleaning 1 (SC 1) and sulfuric acid, which are used for the cleaning process in manufacturing a general photomask. Thereafter, the volume prepared for the observation of air molecular source was 420ml and pre-treated using a special container made of quartz (Quartz), and then subjected to ion chromatography (Ion Chromatography) analysis. The volume of di-water used for pretreatment at this time was 200 ml, and the ultra pure water containing impurity ions generated in the phase inversion film after heat treatment for 120 degrees / 20 minutes using autoclave equipment. IC analysis was performed using 10 ml.

Example 4 Comparative Example 4 Example 5 Sulfate ion 86 ppb / mask 425 ppb / mask 531 ppb / mask Ammonium ion 103 ppb / mask 532 ppb / mask 591 ppb / mask

Table 1 Ion Analysis Results

Table 1 shows the ion analysis results of Example 4 and Comparative Examples 4 and 5. As a result of ion analysis, sulfuric acid and ammonium ion adsorption amount of Comparative Examples 4 and 5 was analyzed to be higher than that of Example 4. Since sulfuric acid and ammonium ions, which are the causes of growth defects, are adsorbed to the phase inversion film according to the comparative example, the growth defects are expected to be generated when irradiated with exposure energy of 193 nm. Growth defects generated by irradiating 12kJ / cm 2 exposure energy to the Examples and Comparative Examples, respectively, were observed through an electron microscope.

Example 4 Comparative Example 4 Comparative Example 5 Haze Numbers (Mask Full) 13 75 96

<Table 2> Growth defect observation results @ 12kJ

Table 1 shows growth defect observation results for Examples and Comparative Examples. This is the same as the ion analysis results it can be seen that more growth defects occur in the comparative example in which a lot of sulfuric acid and ammonium ions that are the cause of growth defects are adsorbed. In Comparative Example 4, since a relatively large amount of silicon is included in comparison with the Example, the composition of the thin film is inconsistent and the surface energy of the thin film is increased to increase the adsorption energy, thereby causing the adsorption of a large amount of sulfuric acid and ammonium ions. A large number of growth defects have occurred. In the case of Comparative Example 5, the content of silicon in the composition ratio of the phase inversion film was smaller than that of the embodiment, but due to the large amount of nitrogen, the bonding of SiN and MoN was increased, causing mismatches in the film composition. Resulted. As a result, in order to improve the stability of the thin film, adsorption of more ions on the surface is pursued to stabilize the thin film, resulting in a large amount of ion adsorption. As a result, a large number of growth defects were generated. On the other hand, in the case of Example, the composition ratio of Mo, Si, and N is appropriately added, so that the phase inversion film can be manufactured in a relatively stable state, and thus a small amount of ion adsorption occurs, thereby causing a small amount of growth defect. Eventually, by controlling the composition ratio of the phase inversion film, it becomes possible to manufacture a phase inversion film with less growth defects, and finally, a phase inversion photomask having high quality becomes possible.

<Example 5 and Comparative Examples 6 and 7>

Examples 5 and Comparative Examples 6 and 7 measured birefringence for using the MoSiN phase inversion films for ArF prepared in Examples 4 and 4 and 5 for immersion lithography. Birefringence is a situation in which birefringence is a problem as the numerical aperture NA increases in immersion lithography for implementing CDs of 65 nm or less. Accordingly, the birefringence of the phase inversion film according to Examples and Comparative Examples was measured for a 142 x 142 mm area using Uniopt's ABR-10A-30A equipment. At this time, the birefringence of the transparent substrate was applied to the transparent substrate having the same birefringence.

Composition ratio (Mo: Si: N) Birefringence Remarks 10:60:30 at% 1.56 nm / phase inversion film thickness Example 5 8:64:28 at% 2.32nm / Phase Inverter Thickness Example 6 7:45:48 at% 3.45nm / Phase Inverter Thickness Example 7

<Table 3> Measurement results of birefringence of phase inversion film

Table 3 is a result of measuring the birefringence of the phase inversion film prepared in Example 5 and Comparative Examples 6, 7. As a result of the birefringence measurement, the excellent birefringence was measured in Example 5, whereas the large birefringence value was measured in Comparative Examples 6 and 7. As birefringence increases, degree of polarization (DoP) increases during immersion lithography, resulting in a large CD error, which makes it difficult to fabricate a semiconductor device having excellent performance. The large birefringence measured in the comparative example causes microcrystallization in the thin film as silicon and nitrogen are added more than appropriate amounts. Due to this microcrystallization, more optical axes for exposure light are formed, which makes the birefringence characteristic of the phase inversion film even more pronounced. As a result, large birefringence is measured, and eventually, high quality 65nm and 45nm CD implementations are difficult. On the other hand, in Example 5, an appropriate amount of silicon and nitrogen are added to form a phase inversion film having a low birefringence characteristic, thereby enabling a high quality semiconductor circuit CD.

1 is a cross-sectional view of a phase inversion film formed on a transparent substrate according to the present invention.

2 is a cross-sectional view of a phase inversion film including a metal film according to the present invention.

<Explanation of symbols for main parts of drawing>

1: transparent substrate 2: phase inversion film

3: metal film 4: light shielding film

5: antireflection film 6: metal film

Claims (22)

In a halftone phase inverted blank mask having at least one selected from a phase inversion film, light shielding film, antireflection film, and resist film on a transparent substrate, The phase inversion film is formed from a sputtering target having a thickness of 2 ~ 7mm, The phase inversion film is used for KrF lithography using an exposure wavelength of 248 nm, The phase inversion film essentially contains molybdenum, silicon, nitrogen, The composition ratio of the phase inversion film is 7-15 at% molybdenum, 55-63 at% silicon, 28-35 at% nitrogen, The phase inversion film has an amorphous shape and has a concentration of surface impurity ions of 400 ppbv or less in order to control growth defects of the phase inversion film. The method of claim 1, The phase shift blank mask, wherein the phase shift film contains 5 at% or less of oxygen. In a halftone phase inverted blank mask having at least one selected from a phase inversion film, light shielding film, antireflection film, and resist film on a transparent substrate, The phase inversion film is formed from a sputtering target having a thickness of 2 ~ 7mm, The phase inversion film is used for KrF lithography using an exposure wavelength of 248 nm, In the sputtering process for forming the phase inversion film, 30 to 40 vol% argon, 60 to 70 vol% nitrogen, and additionally gas containing carbon and oxygen, Power density is 1 ~ 2W / cm ² , pressure is 1x10 ^-2 ~ 1x10 ^-4 torr, The phase inversion film is in an amorphous form and has a concentration of surface impurity ions of 400 ppbv or less in order to control the growth defect of the phase inversion film. In a halftone phase inverted blank mask having at least one selected from a phase inversion film, light shielding film, antireflection film, and resist film on a transparent substrate, The phase inversion film is formed from a sputtering target having a thickness of 2 ~ 7mm, The phase inversion film is used for KrF lithography using an exposure wavelength of 248 nm, The thickness of the phase inversion film is 850 ~ 950Å, transmittance is 4.5 ~ 9%, The phase inversion film is in an amorphous form and has a concentration of surface impurity ions of 400 ppbv or less in order to control the growth defect of the phase inversion film. The method of claim 3, wherein The material of the phase shift film is a half-tone phase shift blank mask, characterized in that essentially comprises molybdenum, silicon, nitrogen. The method of claim 4, wherein The material of the phase shift film is a half-tone phase shift blank mask, characterized in that essentially comprises molybdenum, silicon, nitrogen. In a halftone phase inverted blank mask having at least one selected from a phase inversion film, light shielding film, antireflection film, and resist film on a transparent substrate, The phase inversion film is formed from a sputtering target having a thickness of 2 ~ 7mm, The phase inversion film is used for ArF lithography using an exposure wavelength of 193 nm, The phase inversion film essentially contains molybdenum, silicon, nitrogen, The composition ratio of the phase inversion film is 5 to 12 at% of molybdenum, 57 to 65 at% of silicon, and 28 to 35 at% of nitrogen. The phase inversion film is in an amorphous form and has a concentration of surface impurity ions of 400 ppbv or less in order to control the growth defect of the phase inversion film. The method of claim 7, wherein The phase shift blank mask, wherein the phase shift film contains 5 at% or less of oxygen. In a halftone phase inverted blank mask having at least one selected from a phase inversion film, light shielding film, antireflection film, and resist film on a transparent substrate, The phase inversion film is formed from a sputtering target having a thickness of 2 ~ 7mm, The phase inversion film is used for ArF lithography using an exposure wavelength of 193 nm, In the sputtering process for forming the phase inversion film, 15 to 25 vol% argon, 75 to 85 vol% nitrogen, additionally gas containing carbon and oxygen, Power density is 1 ~ 2W / cm ² , pressure is 1x10 ^-2 ~ 1x10 ^-4 torr, The phase inversion film is in an amorphous form and has a concentration of surface impurity ions of 400 ppbv or less in order to control the growth defect of the phase inversion film. In a halftone phase inverted blank mask having at least one selected from a phase inversion film, light shielding film, antireflection film, and resist film on a transparent substrate, The phase inversion film is formed from a sputtering target having a thickness of 2 ~ 7mm, The phase inversion film is used for ArF lithography using an exposure wavelength of 193 nm, The thickness of the phase inversion film is 630 to 680 Pa, and the transmittance is 4.5 to 7%, The phase inversion film is in an amorphous form and has a concentration of surface impurity ions of 400 ppbv or less in order to control the growth defect of the phase inversion film. The method of claim 9, The material of the phase shift film is a half-tone phase shift blank mask, characterized in that essentially comprises molybdenum, silicon, nitrogen. The method of claim 10, The material of the phase shift film is a half-tone phase shift blank mask, characterized in that essentially comprises molybdenum, silicon, nitrogen. In a halftone phase inverted blank mask having at least one selected from a phase inversion film, light shielding film, antireflection film, and resist film on a transparent substrate, In the case of forming the phase inversion film through sputtering, It is formed through a sputtering target with a thickness of 2-7 mm, The phase inversion film is in an amorphous form and has a concentration of surface impurity ions of 400 ppbv or less in order to control the growth defect of the phase inversion film. The method of claim 13, The half-tone phase inversion blank mask, characterized in that the material of the sputtering target is composed of molybdenum and silicon. The method of claim 13, When the phase inversion film is used for KrF lithography using an exposure wavelength of 248 nm, The material of the sputtering target is composed of molybdenum and silicon, At this time, the composition ratio of molybdenum and silicon molybdenum is 15 to 25 at%, silicon is a half-tone phase inversion blank mask, characterized in that 75 to 85 at%. The method of claim 13, When the phase inversion film is used for ArF lithography using an exposure wavelength of 193 nm, The material of the sputtering target is composed of molybdenum and silicon, In this case, the composition ratio of molybdenum and silicon is 5 to 15 at% molybdenum, 85 to 95 at% silicon halftone type phase inverted blank mask. The method of claim 1, A halftone phase inversion blank mask, characterized in that the phase inversion film is formed in a single layer or / and multilayer. The method of claim 7, wherein A halftone phase inversion blank mask, characterized in that the phase inversion film is formed in a single layer or / and multilayer. In the halftone phase inversion blank mask for ArF immersion lithography in which at least one film selected from a phase inversion film, a light shielding film, an antireflection film, and a resist film is formed on a transparent substrate, The birefringence of the phase inversion film is 193nm to 2nm / phase inversion film thickness, characterized in that the half-tone phase inversion blank mask. A method for producing a halftone phase shift blank mask for producing the halftone phase shift blank mask according to any one of claims 1 to 19. 20. A halftone phase inversion photomask fabricated through the halftone phase inversion blank mask of any one of claims 1-19. 20. A method for manufacturing a halftone phase inversion photomask prepared by the halftone phase inversion blank mask according to any one of claims 1 to 19.

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