KR100869268B1 - Half-tone phase shift blankmask, half-tone phase shift photomask and it's manufacturing method - Google Patents

Abstract

The halt tone type phase-inversion blank-mask and halt tone type phase shift photo mask of the High-end class are provided to achieve the excellent property. The phase shift layer(20) includes the molybdenum silycide(MoSi) and tantalum(Ta) to improve the haze property, the reflectivity property, and the dry etching property and aging characteristic. The ratio of the tantalum(Ta): the molybdenum(Mo) is 1:0.5 or 1:3. The total density of the anion and the cation on the surface of the phase shift layer is 50 ppbv or less. The phase shift layer is in the amorphous state. The thickness of the sputtering target used in the formation of the phase shift layer is 2 ~ 7 mm.

Description

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

TECHNICAL FIELD The present invention relates to a halftone phase inversion blank mask and a halftone phase inversion photomark and a method for manufacturing the same, and in particular, a halftone phase inversion blank mask and a halftone phase inversion photomark suitable for KrF at 248 nm and ArF lithography at 193 nm. And a method for producing the same.

Photolithography for the manufacture of semiconductor integrated circuits generally uses binary blank masks in which chromium-based light-shielding films, anti-reflection films, and resists are sequentially stacked on transparent substrates, but as the pattern size becomes smaller, higher resolution and process margins are secured. Phase inverted blank masks and photomasks have also been developed and used. In particular, halftone type phase inversion blank masks and photomasks which are easy to manufacture and excellent in performance are mainly used.

As the material of the halftone phase inversion blank mask currently used, phase inversion films such as MoSiO, MoSiON, MoSiN, etc., containing MoSi-based two-component materials, are used. However, materials such as the generally blank mask, and ions of sulfuric acid at the surface of the thin film on the chemicals used in the cleaning process of the photomask (SO ₄ ^{2 -)} easily ion adsorption such as, and ammonium ions (NH ₄ ⁺⁾ There is a problem that a lot of growth defects occur on the surface of the phase inversion film due to these ions. In addition, since the phase inversion material is formed in an unstable structure, the stability of the thin film is deteriorated, so that the pattern profile is not good during dry etching, and the transmittance and the phase difference greatly change with time after the formation of the phase inversion film. In addition, the MoSi-based material has a problem in that the inspection is not accurate because the contrast decreases during the inspection due to the low reflectance in the inspection wavelength. In addition, in the case of the MoSi-based material, a lot of particles are generated during the formation of the phase inversion film, causing a CD error when transferring the pattern to the wafer. Due to these problems, it becomes difficult to manufacture a high performance halftone type phase inversion photomask, and eventually, it is difficult to manufacture a high performance semiconductor device.

The present invention is to solve the above problems, and relates to the film formation and composition ratio of the phase inversion film in the half-tone phase inversion blank mask. In particular, it is possible to form a phase inversion film having excellent characteristics by controlling the composition ratio of the thin film, and through such a thin film, a halftone phase inversion blank mask having excellent ion adsorption characteristics, haze characteristics, reflectance characteristics, dry etching characteristics, particle characteristics, and Aging characteristics And a method of manufacturing a halftone phase inversion photomask.

Accordingly, an object of the present invention is to provide a halftone phase inversion blank mask and a halftone phase inversion photo mask having excellent characteristics in a high-end halftone phase inversion blank mask and halftone phase inversion photo mask.

A characteristic of the method for manufacturing a halftone phase inversion blank mask according to the present invention for achieving the above object is that the phase inversion film, the light shielding film, the antireflection film, and the resist film are sequentially formed on the transparent substrate sequentially. do.

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

a1) preparing a transparent substrate;

b1) forming a phase inversion film on the transparent substrate prepared in step a1);

c1) forming a metal film on the phase inversion film formed in step b1);

d1) preferably, forming a phase shift blank mask by coating a resist on the metal film formed in step c1) to form a resist film.

Hereinafter, each step will be described in more detail.

In the a1) step, the transparent substrate is made of soda lime, synthetic quartz or calcium fluoride (CaF ₂ ), and an ArF laser (193 nm) at an i-line (365 nm) which is a lithography light source. Substrates having a size of at least 5 inches having a transmission of at least 85% or more in wavelength. In addition, it has a birefringence of 4nm / 6.35mm or less at 193 nm.

In the step b1), the phase inversion film can be composed of a single layer film or a multilayer film of two or more layers, and essentially includes molybdenum silicide (MoSi) and has excellent ion adsorption properties, Haze properties, reflectance properties, dry etching properties, For particle and Aging properties, transition metals such as cobalt (Co), tantalum (Ta), tungsten (W), chromium (Cr), vanadium (V), palladium (Pd), titanium (Ti) and niobium (Nb) , Zinc (Zn), hafnium (Hf), germanium (Ge), aluminum (Al), platinum (Pt), manganese (Mn), iron (Fe), ruthenium (Ru), antonium (Sb), nickel ( Ni), cadmium (Cd), zirconium (Zr), tin (Sn), gallium (Ga), niobium (Nb) is characterized in that it comprises at least one transition metal. Preferably, at least one transition metal and molybdenum silicide (MoSi) selected from tantalum (Ta), chromium (Cr), tungsten (W), niobium (Nb), palladium (Pd), platinum (Pt) and zirconium (Zr) It is characterized in that the phase inversion film made of a compound comprising essentially, more preferably comprises a transition metal tantalum (Ta) and molybdenum silicide (MoSi).

In the step b1), in the case of using a single target added with a transition metal Ta to the MoSi material to improve the ion adsorption properties, Haze properties, reflectance properties, dry etching properties, particle properties and Aging properties of the phase inversion film, At this time, the target composition is preferably 2 to 18 at% Mo, 2 to 8 at% Ta, and 75 to 95 at% Si in order to improve the above characteristics. More preferably, the exposure wavelength is for KrF. , Mo is 10-18 at%, Ta is 2-8 at%, Si is 75-85 at%, and when the exposure wavelength is for ArF, Mo is 2-8 at% and Ta is 2-8 at% And Si is 85 to 95 at%.

In the step b1), in order to have the ion adsorption characteristics, Haze characteristics, reflectance characteristics, dry etching characteristics, particle characteristics, and Aging characteristics of the phase inversion film, the composition ratio of the molybdenum (Mo) is 2 to 15 at %, 2 to 20 at% transition metal and 50 to 65 at% silicon (Si). In particular, when the transition metal is tantalum (Ta), the composition ratio of tantalum (Ta) is characterized in that 2 to 15 at%. In particular, in the case of the KrF halftone phase inversion film having an exposure light of 248 nm, molybdenum (Mo) is 7 to 15 at%, tantalum (Ta) is 3 to 12 at%, and silicon (Si) is 50 to It is preferable that it is 63 at%, and in the case of the halftone phase inversion film for ArF having exposure light of 193 nm, molybdenum (Mo) is 2 to 10 at%, tantalum (Ta) is 1 to 10 at%, and silicon in the phase inversion film. It is preferable that (Si) is 53-65 at%. If the composition ratio of tantalum (Ta) has a composition ratio of more than 12 at%, the amount of tantalum (Ta) atoms is excessively present in the phase inversion film, so that the reaction between Mo, Ta, Si, and N is not sufficient. Tantalum (Ta) atoms, which cannot be gathered at the interface, deteriorate ion adsorption characteristics and Haze characteristics.

In the step b1), the ratio of tantalum (Ta): molybdenum (Mo) constituting the phase inversion film is characterized in that 1: 0.5 to 1: 3. At this time, if the ratio of molybdenum is less than 0.5, the specific gravity of Ta in the phase inversion film is excessively high, and the particle characteristics are deteriorated. If the ratio of molybdenum is more than 3, the specific gravity of molybdenum is increased, thereby deteriorating ion adsorption characteristics and dry etching characteristics.

In the step of b1), when the phase inversion film comprises a molybdenum composition ratio of 15 at% or more, there is a problem in that the pattern profile is bad during dry etching. Therefore, in order to secure excellent dry etching of the phase shift film, the composition ratio of molybdenum in the phase shift film should be adjusted to 1 to 15 at%.

In the step b1), if the content of silicon (Si) in the phase inversion film is too small, it is difficult to obtain the transmittance at the exposure wavelength, while if too large, the reflectance characteristic at the inspection wavelength becomes worse. Therefore, in order to have a reflectance characteristic of 40% or more at the inspection wavelength, the composition ratio of silicon (Si) in the phase inversion film should be adjusted to 50 to 65 at%.

In the step b1), in order to form the phase inversion film, tantalum (Ta), chromium (Cr), tungsten (W), niobium (Nb), palladium (Pd), platinum (Pt), and zirconium (Zr) Single target or a compound consisting of at least one transition metal selected from molybdenum (Mo) and silicon (Si), tantalum (Ta), chromium (Cr), tungsten (W), niobium (Nb), palladium (Pd), Sputtering is performed using at least one target selected from platinum (Pt) and zirconium (Zr) and a compound target consisting of molybdenum (Mo) and silicon (Si), or tantalum (Ta), chromium (Cr), Compound target consisting of at least one transition metal selected from tungsten (W), niobium (Nb), palladium (Pd), platinum (Pt) and zirconium (Zr) and silicon (Si), molybdenum (Mo) and silicon (Si) The method of sputtering and film-forming using the compound target which consists of these is preferable.

In the step b1), the inert gas is used at least one selected from the group consisting of argon (Ar), helium (He), neon (Ne), krypton (Kr) and xenon (Xe) and the active gas is Oxygen (O ₂ ), Nitrogen (N ₂ ), Carbon Monoxide (CO), Carbon Dioxide (CO ₂ ), Nitrous Oxide (N ₂ O), Nitrogen Oxide (NO), Nitrogen Dioxide (NO ₂ ), Ammonia (NH ₃ ) and Methane One or more gases selected from the group consisting of (CH ₄ ) are used. Particularly, in the case of a reactive gas containing nitrogen atoms, when the nitrogen atoms are too large in the phase inversion film, it is difficult to secure the reflectance at the inspection wavelength, and when it is too low, the transmittance characteristics at the exposure wavelength cannot be obtained. Therefore, it is preferable that the composition ratio of nitrogen (N) in the phase inversion film is in the range of 25 to 35 at%. In particular, when the exposure light is a KrF phase inversion film of 248 nm, the ratio of gas containing nitrogen (N) during sputtering is preferably 40 to 60 vol%, and when the exposure light is a 193 nm ArF phase inversion film. It is preferable that the ratio of the gas containing nitrogen (N) at the time of sputtering is 70-90 vol%.

In the step b1), it is also possible to include a small amount of oxygen when forming the phase inversion film. At this time, the composition ratio of oxygen in the phase inversion film is preferably 5 at% or less. When the composition ratio of oxygen is out of the upper limit, the transmittance is excessively high, and the chemical resistance of chemicals such as sulfuric acid or ammonia is deteriorated, thereby degrading the quality of the phase shift film.

In the step b1), DC sputter, R.F. Methods such as sputtering and ion beam deposition may be used, and the power is characterized by reactive sputtering at 0.1 kW to 4 kW.

In the step b1), the pressure in the vacuum chamber during the sputtering of the phase inversion film is preferably performed at 0.1 ~ 0.4 Pa. Sputtering at a pressure of 0.1 Pa or less causes damage to the substrate if the acceleration energy of the sputtered atoms is too large, resulting in poor transmittance, reflectance and surface roughness of the final phase shift film. In addition, when the pressure is sputtered at 0.4 Pa or more, the energy of the sputtering atoms is deposited on the substrate, and thus the energy to move to a stable position is insufficient. Therefore, the density of the phase inversion film is decreased, resulting in deterioration of safety or deterioration of particle characteristics due to the increase of impurities in the chamber. Has a problem. When the surface roughness is 0.2 nm or more, diffuse reflection and scattering of light incident upon inspection increase, making accurate inspection difficult, and accurate reflection of exposure occurs due to diffuse reflection and scattering of exposure light even after exposure after patterning. Therefore, when the phase shift film is formed, the sputtering pressure should be formed in the range of 0.1-0.4 Pa.

In the step a1), the thickness of the sputtering target for forming the phase inversion film is characterized in that 2 ~ 7mm. 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 c1), when the metal film is sequentially formed from a transparent substrate as a light shielding film and an antireflection film, the light shielding film is a thin film including one or more selected from the group consisting of chromium, tungsten, tantalum, and titanium, and includes argon, helium, and neon. And sputtering using at least one selected inert gas selected from xenon and krypton, and at least one selected active gas selected from oxygen, nitrogen, carbon monoxide, carbon dioxide, nitrous oxide, nitrogen oxide, nitrogen dioxide, ammonia and methane.

In the step c1), when the metal film is sequentially composed of a light shielding film and an antireflection film from a transparent substrate, the antireflection film is formed of chromium, tungsten, tantalum, molybdenum silicide, and titanium with a metal as a matrix. As the thin film containing at least one inert gas selected from argon, helium, neon, xenon and krypton, and at least one active gas selected from oxygen, nitrogen, carbon monoxide, carbon dioxide, nitrous oxide, nitrogen oxide, nitrogen dioxide, ammonia and methane It is characterized in that the sputtering.

In the step c1), when the metal film is sequentially formed from the transparent substrate as the light blocking film and the antireflection film, the light blocking film and the antireflection film are cobalt (Co), tantalum (Ta), tungsten (W), chromium (Cr), and vanadium ( V), palladium (Pd), titanium (Ti), niobium (Nb), zinc (Zn), hafnium (Hf), germanium (Ge), aluminum (Al), platinum (Pt), manganese (Mn), iron ( Fe), ruthenium (Ru), antonium (Sb), nickel (Ni), cadmium (Cd), zirconium (Zr), tin (Sn), gallium (Ga), niobium (Nb), silicon (Si) , At least one material selected from metal silicides. In addition, the light shielding film and the anti-reflection film are characterized in that the present in the form of oxidation, nitriding, carbonization, oxynitride, carbonitride, oxidized carbon, oxynitride.

In the step c1), when the metal film is sequentially formed from the transparent substrate as the light shielding film and the anti-reflection film, a thin film that functions as an etch stop layer may be selectively formed between the light shielding film and the phase inversion film. In this case, the etch stop layer is not etched in the medium for etching the phase inversion film and the light shielding film. The thickness of the etch stop layer is 300 Å or less and the material of the etch stop layer is cobalt (Co), tantalum (Ta), tungsten (W), chromium (Cr), Vanadium (V), palladium (Pd), titanium (Ti), niobium (Nb), zinc (Zn), hafnium (Hf), germanium (Ge), aluminum (Al), platinum (Pt), manganese (Mn), Iron (Fe), ruthenium (Ru), antonium (Sb), nickel (Ni), cadmium (Cd), zirconium (Zr), tin (Sn), gallium (Ga), niobium (Nb), silicon ( Si), at least one material selected from metal silicides. In addition, the light shielding film and the anti-reflection film are characterized in that the present in the form of oxidation, nitriding, carbonization, oxynitride, carbonitride, oxidized carbon, oxynitride.

In the step c1), when the metal film is sequentially formed from the transparent substrate as the light shielding film and the antireflection film, a thin film that functions as an etch stop layer may be selectively formed between the antireflection film and the resist film. In this case, the etch stop layer is not etched in the medium for etching the anti-reflection film. In addition, the thickness of the etch stop layer is 300Å or less, and the material is cobalt (Co), tantalum (Ta), tungsten (W), chromium (Cr), vanadium (V), palladium (Pd), titanium (Ti), and niobium (Nb). ), Zinc (Zn), Hafnium (Hf), Germanium (Ge), Aluminum (Al), Platinum (Pt), Manganese (Mn), Iron (Fe), Ruthenium (Ru), Antonium (Sb), Nickel (Ni), cadmium (Cd), zirconium (Zr), tin (Sn), gallium (Ga), niobium (Nb), silicon (Si), characterized in that it comprises at least one material selected from metal silicides . In addition, the light shielding film and the anti-reflection film are characterized in that the present in the form of oxidation, nitriding, carbonization, oxynitride, carbonitride, oxidized carbon, oxynitride.

In the step c1), when the metal film is sequentially formed from the transparent substrate as the light shielding film and the antireflection film, a thin film that functions as an etch stop layer may be selectively formed between the phase inversion film and the light shielding film and between the antireflection film and the resist film. Characterized in that it can. In this case, the etch stop layer is not etched in the medium for etching the phase inversion film and the light shielding film. In this case, the thickness of the upper etch stop layer is thinner than the lower etch stop layer.

In the step d1), the resist film is a chemically amplified resist, characterized in that the thickness is less than 4000Å.

In addition, the method for manufacturing a halftone phase inversion photomask according to the present invention,

Forming a resist film pattern, an antireflection film pattern, a light shielding film pattern, and a phase inversion film pattern through a process that is typically used in the manufacture of a phase inversion photomask on the halftone phase inversion mask blank manufactured by the method described above in a1) to e1). After the step of removing the unnecessary resist film pattern, it is preferable to produce a phase inversion photomask.

Through the phase shift film deposition technology according to the present invention, when the halftone phase shift blank mask and the photomask are manufactured, it is possible to manufacture the halftone phase shift blank mask having excellent thin film safety. In particular, it is possible to manufacture a halftone phase inversion blank mask having excellent ion adsorption characteristics, Haze characteristics, reflectance characteristics, dry etching characteristics, particle characteristics, and Aging characteristics. This high-end halftone phase inverted blank mask enables not only the life of the photomask to be extended but also accurate pattern transfer without error when transferring the pattern of the wafer, resulting in improved productivity and high quality halftone phase inverted blank. The manufacture of masks and photomasks is possible.

The present invention will be described in detail by way of examples, but the examples are only used for the purpose of illustration and description of the present invention and are not used to limit the scope of the present invention as defined in the meaning or claims. 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)

Sputtering targets of various compositions were used to form the phase inversion film. In order to improve the ion adsorption, haze, reflectance, dry etching, particle, and aging characteristics of the phase inversion film, a single target with a transition metal added to the MoSi material was used. At this time, the target composition is preferably 2 to 18 at% Mo, 2 to 8 at% Ta, and 75 to 95 at% Si in order to improve the above characteristics. More preferably, the exposure wavelength is for KrF. , Mo is 10-18 at%, Ta is 2-8 at%, Si is 75-85 at%, and when the exposure wavelength is for ArF, Mo is 2-8 at% and Ta is 2-8 at% And Si is 85 to 95 at%.

In the embodiment according to the present invention, a single sputtering target to which Ta of various compositions within the above range was added was used. Using this sputtering target, a 6-inch transparent substrate having a surface area of 231.04 cm 2 was prepared, and a phase shift film for ArF was formed using a DC magnetron sputtering device. Sputtering conditions used in the deposition were Ar gas 5 ~ 50 sccm, N ₂ gas 50 ~ 95 sccm gas was used to apply a power of 1 ~ 1.5 kW to form a phase inversion film. In addition, all of the phase inversion films satisfied the spectra of 5% to 6% and 630 Hz to 680 Hz at 193 nm.

A light shielding film and an antireflection film were sequentially formed on the phase inversion film thus prepared, and then a resist film was coated to prepare a halftone phase inversion blank mask. In order to evaluate ion adsorption characteristics and Haze characteristics, chemical treatment was performed on H ₂ SO ₄ solution and NH ₄ OH solution.

Ta content [at%] Ion concentration [ppbv] Haze Properties [EA / ㎠] Example 1 2 10.14 1.0 Example 2 3 11.04 0.9 Example 3 4 10.98 1.0 Example 4 6 10.53 1.2 Example 5 8 10.51 1.1 Example 6 10 11.65 0.9 Comparative Example 1 One 54.15 9.1 Comparative Example 2 12 51.22 9.3 Comparative Example 3 15 56.15 10.8

TABLE 1

Table 1 shows the density | concentration of the adsorption ion on the surface of the phase inversion film about Examples 1-6 and Comparative Examples 1-3, and the Haze Defect number after exposure. Comparative Examples 1 to 3 are MoSi phase inversion films containing 1 at%, 12 at%, and 15 at% of Ta. Exposure conditions were exposed at 10 kJ exposure energy using a 193 nm laser. As can be seen from the above results, it can be seen that Examples 1 to 6 to which Ta is added are superior to the surface adsorption and Haze characteristics, compared to Comparative Examples 1 to 3. The composition of Ta in the phase inversion film showed adsorption ion concentration of 12 ppbv or less in the range of 2 to 10 at%, but rapidly increased in the range of 1 or less or 10 at% or more. In addition, the number of Haze Defects increased drastically due to the increase in ion concentration. This is because the bonding state of Mo and Si does not bond well, which results in weak Van Der Waals bonding, and the surface energy state of the thin film forming such bonding becomes very unstable. Therefore, the MoSi-based phase shift film SO ₄ ^{2 -,} there are Chemical residues and electrostatic coupling to the property to lower the surface energy by absorption through the surface, such as NH ₄ ^+. However, due to the malleable nature of Ta, due to the addition of Ta in an appropriate range, the bonding force of Mo and Si forms a covalent bond of Mo-Ta-Si in the Van Der Waals bond, thereby achieving a stable bond. The MoTaSi phase inversion film has a considerably low surface energy state. However, when Ta is added to the thin film at less than 2 at%, the effect of Ta could not be confirmed because the amount of Ta is insufficient to promote the bonding of Mo and Si. When Ta is added above a critical concentration to improve the binding force of Mo-Ta-Si, Ta atoms that cannot form a bond segregate at the interface of phases such as Mo-Si, Si-Ta, Mo-Ta-Si, etc. (Segregation), unstable and unstable state, the energy state of the surface and the inside of the thin film is a very high unstable state. Therefore, in order to have a stable bonding structure by adsorbing ions to lower the surface and internal energy, surface adsorption ion properties and Haze properties deteriorate in a phase inversion film containing 10 at% or more of Ta.

Table 2 shows the reflectance characteristics and dry etching characteristics of Examples 3, 4 and 5 and Comparative Examples 1, 2 and 3.

Ta content [at%] Reflectance Characteristics [%] Dry etching characteristics LER [nm] Slpoe [°] Example 3 4 40 1.9 87 Example 4 6 43 1.9 85 Example 5 8 44 1.8 87 Comparative Example 1 One 21 7.3 80 Comparative Example 2 12 28 6.9 81 Comparative Example 3 15 23 7.2 79

TABLE 2

Examples 3 to 5 are MoTaSi-based phase inversion films containing Ta in a predetermined range (2 to 10 at%), and Comparative Examples 1 to 3 are MoTaSi-based phase inversion films containing less than 2 at% and 10 at% or more of Ta. As can be seen from Table 2, in Examples 3 to 5, by adding a transition metal Ta to a predetermined range (2 to 10 at%), the effect of increasing the reflectance at 355 nm, which is the inspection wavelength, can be obtained. In other words, the increase in reflectance at the inspection wavelength leads to an increase in contrast and more accurate inspection as the contrast increases. On the other hand, in Comparative Examples 1 to 3, since the reflectance at the inspection wavelength is in the range of 20 to 30%, it is difficult to accurately perform the inspection. Also, during dry etching, dry etching characteristics can be evaluated through line edge roughness (LER), which is a pattern profile, and a slope of a pattern. In case of MoTaSi phase inversion film (Examples 3 to 5) added with 2 to 10 at% of Ta, the LER shows excellent characteristics of 2 nm or less, while MoTaSi phase inversion film containing less than 2 at% and more than 10 at% of transition metal. (Comparative Examples 1 to 3) showed a LER value of 7 nm level. In addition, the slope of the pattern also obtained a result close to 90 ° in the MoTaSi-based phase inversion film (Examples 3 to 5) to which 2 to 10 at% Ta was added. In the case of MoTaSi-based phase inversion films (Comparative Examples 1 to 3) containing less than 2 at% and more than 10 at% of Ta, fine crystallization occurred during the formation of the phase inversion film, resulting in poor pattern profile during dry etching. In the case of the MoTaSi-based phase inversion film (Examples 3 to 5) in which excellent Ta is added in a predetermined range (2 to 10at%), the pattern profile is excellent during dry etching because the amorphous state is suppressed by the fine crystallization of the MoTaSi-based material. do.

Therefore, the experimental results of Example 1 showed that the MoTaSi phase inversion film for ArF containing the transition metal Ta was excellent in ion adsorption characteristics, Haze characteristics, reflectance characteristics, and dry etching characteristics. Most preferably, the composition of Ta in the inversion film is 2 to 10 at%. In addition, for application as a MoTaSi-based phase inversion film for KrF, the composition of Ta in the phase inversion film is most preferably 3 to 12 at%.

Next, the Aging Test was performed about Examples 3, 4, and 5 and Comparative Examples 1, 2 and 3. Aging test was conducted for a total of 20 days. After measuring the transmittance after the initial film formation, the change of transmittance was measured while storing for 20 days. The measurement wavelength was 193 nm and the measurement point measured 49 Points of 7 × 7.

Transmittance @ 193 nm [%] As deposit After 24 hours After 72 hours After 240 hours After 480 hours Example 3 5.74 5.75 5.76 5.81 5.83 Example 4 5.66 5.66 5.66 5.70 5.71 Example 5 5.56 5.56 5.57 5.61 5.63 Comparative Example 1 5.42 5.49 5.58 5.77 5.91 Comparative Example 2 5.49 5.52 5.63 5.88 6.02 Comparative Example 3 5.78 5.99 6.04 6.19 6.35

TABLE 3

Table 3 shows the Aging Test results for the Examples and Comparative Examples. The transmittance was measured using an n & k 1512RT (n & k Analyzer, USA) instrument. In the case of the Ta-added example, there was almost no change in the transmittance and the change in transmittance after 20 days was 0.09%, 0.05%, and 0.07%, whereas in the case of the comparative sample, the transmittance increased steadily over time. After the last 20 days, the transmittance change amount increased by 0.49%, 0.53%, and 0.57%. As described above, the bond between Mo and Si does not occur easily, and the bond between Mo and Si in the phase inversion layer forms Van Der Waals bonds that can be easily broken. Therefore, since the unstable bonds are distributed not only inside the thin film but also on the surface, the energy state of the thin film becomes very high. When the phase inversion film in this state is stored in the air for a long time, the bond of Mo-Si is broken and stable bonds such as Mo-O, Mo-N, Si-O, Si-N, etc. The state is lowered but the transmittance is increased. On the other hand, since Ta is added, Mo-Ta-Si has a stable and strong bond, and thus does not react with oxygen, nitrogen, etc. in the atmosphere.

In addition, after fixing the composition ratio of Ta and Si in the phase inversion film, the characteristics of the ArF phase inversion film were evaluated while changing the composition ratio of Mo. To this end, a single sputtering target having various Mo compositions was used, and the sputtering method was performed in the same manner as in Example 1 to form a phase inversion film for ArF.

Mo content [at%] Reflectance [%] Dry etching characteristics LER [nm] Slope [°] Example 7 2 42 1.6 86 Example 8 4 41 1.7 84 Example 9 6 43 1.5 87 Example 10 8 45 1.5 88 Example 11 10 44 1.4 86 Comparative Example 4 One 30 3.8 76 Comparative Example 5 12 27 4.9 72 Comparative Example 6 25 22 6.3 70

TABLE 4

Table 4 shows the reflectance and dry etching characteristics according to the Mo composition ratio in the phase inversion film. When the composition of Mo in the phase inversion film is 2 to 10 at%, the reflectance at the inspection wavelength of 355 nm is excellent. However, above 10 at%, the reflectance rapidly decreased. This is because when Mo is excellent in crystalline characteristics, crystallization does not occur through the combination of Ta and Si in the range of 10 at% or less in the phase inversion film, but when 10 at% or more is present in the phase inversion film, the remaining Mo atoms react with Ta and Si. This is because they start to combine with each other and become crystallized. Therefore, as the Mo content increases, more crystallization occurs and the transmittance increases, but the reflectance at the inspection wavelength decreases. In addition, due to such crystallization, the LER value of the pattern profile suddenly worsens during dry etching of the phase shift film. In addition, the slope of the pattern is also patterned below 80 °.

Therefore, in the ArF phase inversion film, the ratio of Mo in the phase inversion film has a composition in the range of 2 to 10 at%, and thus the halftone phase inversion blank mask for ArF having excellent reflectance at the inspection wavelength, dry etching characteristics, etc. Manufacturing is possible. Moreover, in the case of the phase inversion film which can be used for manufacture of the halftone type phase inversion blank mask for KrF, it is preferable that the ratio of Mo is 7-15 at% in a phase inversion film.

In addition, in order to evaluate the characteristics according to the Si content of the phase inversion film, after fixing the composition ratio of Mo and Ta in the phase inversion film, the characteristics of the ArF phase inversion film were evaluated while changing the composition ratio of Si. To this end, a phase inversion film was formed using a single sputtering target having various Si compositions.

Si content [at%] Reflectance Characteristics [%] Dry etching characteristics LER [nm] Slope [°] Example 12 53 41 1.5 84 Example 13 55 43 1.7 85 Example 14 58 48 1.6 86 Example 15 60 42 1.6 85 Example 16 63 45 1.7 86 Example 17 65 47 1.5 87 Comparative Example 7 50 35 3.8 80 Comparative Example 8 70 27 4.9 75 Comparative Example 9 80 26 4.7 74

TABLE 5

Table 5 shows reflectance characteristics and dry etching characteristics according to the Si composition ratio in the phase inversion film. As can be seen from the above experimental results, when the Si content is 50 at% or less, the reflectance characteristic at the inspection wavelength is low while the reflectance characteristic is 40 to 50% at the inspection wavelength in the range of 53 to 65 at%. Is showing. In addition, when the Si content is 65 at% or more, the reflectance decreases drastically. In addition, the dry etching characteristics showed LER characteristics of about 2 nm or less up to 53 ~ 65 at% of Si, whereas LER rapidly decreased at higher Si contents. Similarly, Pattern Slope characteristics showed more than 80 ° characteristics below 65 at%, whereas Pattern Slope characteristics showed less than 80 ° above 65 at%. This is because when the content of Si in the phase inversion film is 50 at% or less, the reflectance decreases at the inspection wavelength due to the increase in transmittance. In the case of more than 65 at%, too much Si atoms exist in the phase inversion film, resulting in poor dry etching characteristics. . Since the bonding force between Si atoms is very strong, Si atoms which are not reacted form a phase made of Si atoms in the thin film through the reaction, and these phases are formed through very strong bonds, so etching is good during dry etching. There is a problem that is not evenly etched. Therefore, when the Si content of 65 at% or more due to this problem, the dry etching characteristics of the phase inversion film is sharply worsened, and also the reflectance at the inspection wavelength is also reduced.

Si content [at%] Ion concentration [ppbv] Haze Properties [EA / ㎠] Example 13 55 10.61 0.8 Example 14 58 11.04 0.9 Example 15 60 10.14 1.0 Comparative Example 7 50 44.78 7.8 Comparative Example 8 70 45.87 7.3 Comparative Example 9 80 50.14 8.8

TABLE 6

Table 6 shows the results of adsorption ion characteristics and Haze characteristics for the examples. In the range of 53-65 at% of Si, ion concentrations of 11.04 ppbv and Haze defects of 1.0 EA / cm 2 were detected. In the case of the phase inversion film having a Si content of 50 at% or less, since the composition of phases of the phase inversion film is nonstoichiometric due to the lack of sufficient Si content for the reaction of the atoms in the phase inversion film, the thermodynamic and Electrically very high state. Therefore, when Chemical Treatment SO ₄ ^{2 -} is because going to thermodynamic properties, and electrical energy to a lower state by the ions and adsorption such as, NH ₄ ⁺ ions. In addition, when the Si content is 65 at% or more, the phase boundary (Phse Boundary) is increased because a phase composed of Si atoms is present inside and on the surface of the thin film. Since the phase boundary is a region where the Gibbs energy is very high, the increase of the phase boundary surface causes the Gibbs energy to increase as a whole. Therefore, in order to lower Gibbs energy, impurities such as SO ₄ ^{2 −} and NH ₄ ⁺ ions are attracted, thereby deteriorating ion adsorption characteristics and Haze characteristics.

Therefore, for the ArF halftone phase inversion blank mask, it is most preferable that the Si composition ratio in the phase inversion film is 53 to 65 at%. For the half-tone phase inversion blank mask for KrF, the Si composition ratio in the phase inversion film is most preferably 50 to 63 at%.

In addition, an ArF phase inversion film having a composition of 2 to 10 at% Mo, 1 to 10 at% Ta, and 53 to 65 at% Si as the composition of the optimized phase inversion film was formed and evaluated. In order to further improve the stability of the thin film when forming the phase inversion film, the phase inversion film was formed at various sputtering pressures.

Sputtering Pressure [Pa] Transmittance Uniformity [%] Particle [EA] Roubgness [nm] Example 16 0.1 0.42 12 0.15 Example 17 0.2 0.39 11 0.17 Example 18 0.3 0.36 13 0.16 Example 19 0.4 0.34 10 0.19 Example 20 0.5 1.02 23 0.78 Example 21 One 3.05 44 1.32 Example 22 5 5.44 75 3.06 Example 23 10 7.15 112 4.16

TABLE 7

Table 7 shows the characteristics of the phase inversion film according to the sputtering pressure during the formation of the phase inversion film. The transmittance measurement wavelength is 193 nm. The sputtering pressure ranged from 0.1 to 0.4 Pa, and the transmittance uniformity ranged from 0.3% to 0.4%. Particle characteristics were also excellent. In the case of surface roughness, excellent surface roughness values of 0.2 nm or less were shown in the range of 0.1 to 0.4 Pa. On the other hand, in the case of the phase inversion film formed at the sputtering pressure of 0.5 Pa or more, the transmittance uniformity, the particle characteristics, and the surface roughness value are sharply deteriorated. The MFP is shortened and deposited on the substrate without sufficient acceleration energy, resulting in poor surface roughness. Therefore, because of insufficient energy, the sputtered atoms cannot move to a stable position, thereby degrading the safety of the thin film. In addition, as the sputtering pressure decreases to a low vacuum state, impurities in the chamber react with each other in the sputtering process to generate depoic particles, and these particles accumulate on the surface during the phase inversion film deposition. In addition, sputtering in too high a vacuum condition causes the acceleration energy of the sputtered atoms to be too large, causing a problem of damage to the substrate. In addition, when the surface roughness is not good, the diffuse reflection and scattering of the light incident upon inspection increase, which makes it difficult to accurately inspect and the scattering of the exposure light increases, which makes it difficult to accurately transfer the pattern.

Therefore, the sputtering pressure of 0.1 ~ 0.4 Pa is preferable for the production of a phase inversion film capable of implementing stable characteristics when forming the phase inversion film.

1 is a cross-sectional view of a binary blank mask made by the present invention.

2 is a cross-sectional view of a phase inversion blank mask produced by the present invention.

<Description of Symbols for Major Parts of Drawings>

10: transparent substrate

20: phase inversion film

30: light shielding film

40: antireflection film

60: resist film

100: binary mask blank produced by the present invention

200: phase inversion mask blank produced by the present invention

Claims (17)

In a halftone phase inversion blank mask in which a phase inversion film, a metal film, and a resist film are sequentially formed on a transparent substrate, The phase inversion film includes molybdenum silicide (MoSi) and tantalum (Ta) to improve ion adsorption, haze, reflectance, dry etching, and aging properties. The ratio of tantalum (Ta): molybdenum (Mo) constituting the phase inversion film is 1: 0.5 to 1: 3, The sum of the cation and anion concentrations detected on the surface of the phase inversion film is 50 ppbv or less, The phase inversion film is in an amorphous state in which fine crystallization is suppressed, A halftone phase inversion blank mask, which is formed from a sputtering target having a thickness of 2 to 7 mm. delete delete The method of claim 1, When the phase inversion film is applicable to KrF Lithography having an exposure wavelength of 248 nm, the composition ratio of the phase inversion film is 7 to 15 at% of molybdenum (Mo), 3 to 12 at% of tantalum (Ta) and 50 of silicon (Si). Halftone phase inversion blank mask, characterized in that from ~ 63 at% The method of claim 1, When the phase inversion film is applicable to KrF Lithography having an exposure wavelength of 248 nm, A halftone phase inversion blank mask, wherein the composition ratio of the sputtering target used for forming the phase inversion film is 10 to 18 at% molybdenum, 2 to 8 at% transition metal, and 75 to 85 at% silicon. The method of claim 1, When the phase inversion film is applicable to ArF Lithography having an exposure wavelength of 193 nm, the composition ratio of the phase inversion film is 2 to 10 at% of molybdenum (Mo), 2 to 10 at% of tantalum (Ta), and 53 of silicon (Si). A halftone phase inversion blank mask, characterized in that from ~ 65 at%. The method of claim 1, When the phase inversion film is applicable to ArF Lithography having an exposure wavelength of 193 nm, A halftone phase inversion blank mask, wherein the composition ratio of the sputtering target used for forming the phase inversion film is 2 to 8 at% molybdenum, 2 to 8 at% transition metal, and 85 to 95 at% silicon. The method of claim 1, A halftone phase inversion blank mask wherein said phase inversion film further comprises at least one element selected from the group consisting of carbon (C), oxygen (O), nitrogen (N), and hydrogen (H). The method of claim 1, A halftone phase inversion blank mask comprising forming a phase inversion film using a reactive gas containing nitrogen atoms as a reactive gas in order to include nitrogen in the phase inversion film. According to claim 1, A halftone phase inversion blank mask having a composition ratio of nitrogen in the phase inversion film of 25 to 35 at%. The method of claim 1, A halftone phase inversion blank mask for KrF, wherein the reactive gas containing nitrogen is formed at a ratio of 40 to 60 vol% with respect to the total sputtering gas in the formation of the phase inversion film. The method of claim 1, A halftone phase inversion blank mask for ArF, wherein the reactive gas containing nitrogen is formed at a rate of 70 to 90 vol% with respect to the total sputtering gas in the formation of the phase inversion film. The method of claim 1, A halftone phase inversion blank mask, wherein the phase shift film is formed by a method selected from among DC sputtering, RF sputtering, ion beam deposition, and atomic layer deposition. The method of claim 1, When the phase shift film is formed, a halftone phase shift blank mask, wherein a sputtering pressure is formed at 0.1 to 0.4 Pa to improve stability of the thin film. The method according to any one of claims 1 and 4 to 14, The manufacturing method of the halftone phase inversion blank mask containing said phase inversion film. The method according to any one of claims 1 and 4 to 14, A halftone phase shift photomask formed through a halftone phase shift blank mask including the phase shift film. The method according to any one of claims 1 and 4 to 14, A method of manufacturing a halftone phase inversion photomask, which is manufactured through a halftone phase inversion blank mask including the phase inversion film.

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