KR20170043858A - Blankmask and Photomask using the same - Google Patents

Abstract

The present invention provides a phase-shift blank mask which includes a hard film formed by an oxygen-containing tantalum compound, and improves etching rate and surface resistance by controlling the oxygen content of the hard film. According to the present invention, the etching rate can be controlled and damage to a lower light-shielding film during the manufacturing process for photomasks can be reduced by controlling the silicone content of a silicone- or oxygen-containing material in a hard film-forming material. Accordingly, the present invention may provide a phase-shift blank mask and a photomask using the same capable of forming micropatterns of 32 nm or smaller, particularly, 14 nm or smaller or 10 nm or smaller.

Description

[0001] The present invention relates to a blank mask and a photomask using the blank mask,

The present invention relates to a blank mask and a photomask using the blank mask. More particularly, the present invention relates to a blank mask and a photomask using the blank mask for realizing a fine pattern capable of realizing a fine pattern of 20 nm or less, particularly 14 nm or less, more preferably 10 nm or less, Mask and a photomask using the same.

Semiconductor microprocessing technology is becoming a very important factor for the miniaturization of circuit patterns. In order to improve the resolution of a semiconductor circuit pattern, a lithography technique for realizing this is a technique of using a binary blank mask, a phase shifting blank mask using a phase reversal film, a binary blank for a hard mask having a hard film and a light shielding film, Mask (Hardmask Binary Blankmask) and so on.

In recent years, in order to realize a high resolution and to secure a process window margin at the time of wafer printing to a wafer, a laminated structure of a phase reversal film and a light- Studies are underway on blank masks with more layers of film. In addition, in order to secure the depth of focus margin in the phase inversion blank mask, a study on a phase inversion film having a transmittance of 6% as well as a high transmittance phase inversion blank mask of 10% or more and 20% It is progressing.

In the phase inversion blank mask provided with the hard film, the hard film is generally made of silicon (Si) such as silicon oxide (SiO 2) or silicon oxynitride (SiON) in consideration of the dry etching property with the light- ≪ / RTI >

However, as the hard film is formed of an oxide film such as silicon oxide (SiO) or silicon oxynitride (SiON), there arises a problem that the surface sheet resistance value is increased. The high surface resistance of the hard film causes a charge-up phenomenon of an ion beam (e-beam) in manufacturing a photomask, which eventually causes a problem of pattern registration. This poses a greater problem in memory devices as well as in logic devices.

Further, since the hard film is formed of silicon oxide, there arises a problem of adhesion of the resist film formed on the top. In order to solve this problem, an additional process such as a process for improving adhesion such as an HMDS process is required, and a problem that the resist film pattern remains in the developing process due to a high adhesive force even after the HMDS process Occurs. This causes spot defects when the lower hard film is etched, resulting in a problem that the final process yield is deteriorated.

In addition, the hard film formed of silicon (Si) oxide is generally formed thin to a thickness of 4 nm to 10 nm, while the lower phase reversal film has a thickness of 60 nm to 90 nm. As a result, not only the hard film is removed by the fluorine (F) -based gas used in the formation of the phase reversal film pattern but also damages to the lower shielding film of the hard film to reduce the optical density of the light shielding film ≪ / RTI >

The present invention overcomes the above problems and provides a phase reversal blank mask with a hard film for high resolution implementation.

In detail, the hard film provided by the present invention provides an appropriate composition ratio for the Si oxide to solve the above problems. Through this, the etching rate of the hard film is reduced compared to the phase reversal film, so that the effect of removing the hard film and damaging the light shielding film during formation of the phase reversal film pattern can be minimized.

Further, by providing a compound containing at least oxygen in the tantalum as a hard film, it is possible to solve the problem of additional process such as HMDS, occurrence of defects by the additional process, and high sheet resistance.

As a result, a phase inversion blank mask having a hard film finally produced has a photomask capable of forming a fine pattern of 20 nm or less, especially 14 nm, 10 nm, 7 nm or less, and realizing a high resolution Can be manufactured.

A phase inversion blank mask having a hard film according to the present invention comprises a phase reversal film, a light shielding film, a hard film and a resist film on a transparent substrate, and the hard film essentially comprises a metal material and oxygen (O) .

The metal material included in the hard film may include tantalum (Ta), molybdenum (Mo), aluminum (Al), tungsten (W), titanium (Ti), silicon (Si), vanadium (V), cobalt (Ni), Zr, Nb, Pd, Zn, Mn, Cd, Mg, Li, Se, , Copper (Cu), hafnium (Hf), and tin (Sn).

The metallic material included in the hard film may be composed of at least one of tantalum (Ta), carbon, oxygen, and nitrogen. Particularly, in order to reduce the sheet resistance of the tantalum (Ta) compound, slow the etching rate compared to the lower phase reversal film, and reduce the damage of the light shielding film when forming the phase reversal film pattern, It is preferable to contain oxygen (O) in a trace amount. Specifically, it is preferable that the content of oxygen is within 1 at% to 30 at%.

The material of the hard film thus formed may be at least one selected from the group consisting of tantalum oxide (TaO), tantalum oxynitride (TaON) and tantalum oxy-nitride (TaCON), or a form containing boron (B) .

The hard film may be formed in the form of a compound containing silicon and oxygen in the form of silicon (Si) compound. In this case, the content of silicon contained in the hard film is 60 at% or less. When the content of silicon is 60 at% or more, the etching rate is accelerated, thereby acting as an element for damaging the lower shielding film as well as removing the hard film in the phase reversal film pattern forming process. Accordingly, when silicon (Si) is included in the hard film, the content of Si is preferably 60 at% or less, more preferably 50 at% or less.

The thickness of the hard film formed as described above is 2 to 10 nm or less.

In addition, it is preferable that the hard film is slower than the etching rate of the lower phase reversal film. More specifically, it is preferable that the etching rate of the hard film is slower than the etching rate of the phase reversal film by 1/3 times or more, .

The present invention relates to a material for forming a hard film, which controls the etching rate through the content of silicon (Si) in a material containing silicon and oxygen, thereby reducing damages of the lower shielding film during the photomask manufacturing process .

By controlling the oxygen content of the tantalum compound as a hard film, not only the etching rate but also the reduction of the sheet resistance and the shortening of the process such as HMDS relative to the silicon (Si) hard film can be obtained.

Accordingly, the present invention can provide a phase inversion blank mask capable of forming a fine pattern of 32 nm or less, particularly, 14 nm or less, 10 nm or less, and a photomask using the same.

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

Hereinafter, the present invention will be described in detail with reference to the drawings, but it should be understood that the present invention is not limited to these embodiments. For example, And is not intended to limit the scope of the invention. Therefore, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention. Accordingly, the true scope of protection of the present invention should be determined by the technical matters of the claims.

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

1, a blank mask 100 according to the present invention includes a phase reversal film 104, a light shielding film 106, a hard film 112, and a resist film 114 which are sequentially stacked on a transparent substrate 102, .

The transparent substrate 102 is made of quartz glass, synthetic quartz glass, fluorine-doped quartz glass, or the like having a size of 6 inches x 6 inches x 0.25 inches in width x length x thickness.

The flatness of the transparent substrate 102 affects the flatness of a thin film formed on the upper side, for example, a phase reversal film, a light-shielding film, a hard film, etc., Total Indicated Reading), the value is controlled to be 500 nm or less, preferably 200 nm or more preferably 100 nm or less in the region of 142 mm 2.

The phase reversal film 104 is made of a material having an etching selectivity ratio of 10 or more with the light-shielding film 108 as the upper shielding film 106 pattern is etched by the etching mask. The phase reversal film 104 is formed of a material having a high index of refraction and extinction coefficient so as to maintain the optical characteristics and to thin the thickness and increase the chemical resistance. To this end, the phase reversal film 104 may be formed of a material selected from the group consisting of molybdenum (Mo), tantalum (Ta), vanadium (V), cobalt (Co), nickel (Ni), zirconium (Zr), niobium ), Zinc (Zn), chromium (Cr), aluminum (Al), manganese (Mn), cadmium (Cd), magnesium (Mg), lithium (Li), selenium (N), oxygen (O), carbon (C), boron (B), hydrogen (B), and the like are added to the metal material, (H). ≪ / RTI >

The phase reversal film 104 is preferably made of a metal silicide compound containing a transition metal such as silicon (Si) or molybdenum (Mo), or may be doped with nitrogen (N), oxygen (O) C). ≪ / RTI > The phase reversal film 104 is made of, for example, one of Si, SiN, SiC, SiO, SiCN, SiCO, SiNO, SiCON, MoSi, MoSiN, MoSiC, MoSiO, MoSiCN, MoSiCO, MoSiNO, MoSiCON, May further include at least one light element selected from the group consisting of boron (B), fluorine (F), and hydrogen (H) in consideration of the optical, chemical, and physical characteristics and manufacturing process of the film (104).

The phase reversal film 104 is composed of a monolayer film of uniform composition, a continuous film whose composition or composition ratio is changed, and one of two or more multilayer films having mutually different compositions and in which films of different compositions are laminated one or more times.

The phase reversal film 104 may be configured such that the uppermost or topmost film comprises oxygen (O). In detail, if the phase shift film 104 is formed of a silicide (MoSi) compound molybdenum, phase shift film 104 is ozone (O _3), Hot-DI and ammonia (NH ₄ OH), sulfuric acid (H ₂ SO ₄ ), and the like. When the phase reversal film 104 is damaged in the cleaning process or the like, the phase reversal film 104 is thinned, the transmittance is increased, the phase reversal amount is changed, and the required optical properties can not be realized . Accordingly, the present invention is based on the fact that the topmost film comprises oxygen (O), for example, by forming the top layer of the phase reversal film 104 with MoSiON, and by dissolution or corrosion of the phase reversal film 104 generated by the cleaning solution The same deterioration phenomenon can be prevented. The uppermost layer film of the phase reversal film 104 has an oxygen (O) content of 0.1 at% to 20 at%, and the portion of the phase reversal film 104 disposed at the lower portion of the uppermost layer film is composed of various films having different compositions and composition ratios .

The phase reversal film 104 has a thickness of 300 ANGSTROM to 900 ANGSTROM, preferably 500 ANGSTROM to 700 ANGSTROM. When the phase reversal film 104 is formed to include oxygen (O) in the uppermost layer or the uppermost layer film, the section including oxygen (O) in the uppermost layer or the uppermost layer has a thickness of 10 A to 100 A, ) Thickness of 1% to 40%, and preferably has a thickness of 1% to 10%.

The phase reversal film 104 has a transmittance of 5% to 40% with respect to exposure light having a wavelength of 193 nm or 248 nm and has a phase reversal amount of 170 ° to 190 °. If the transmittance of the phase reversal film 104 is lower than 5%, the intensity of exposure light for destructive interference during exposure of the resist film coated on the wafer is lowered and the phase reversal effect is insignificant. If the transmittance is higher than 40% , The resist film applied to the wafer is damaged, resulting in loss of the resist film.

The phase reversal film 104 can be selectively heat-treated at 100 ° C to 500 ° C to adjust chemical resistance and flatness.

The light shielding film 106 is formed of a multilayer film of two or more layers having different composition or composition ratio in consideration of the pattern aspect ratio and the optical characteristics of the film in the pattern etching process and is preferably composed of a first light shielding layer 108 and a second light shielding layer 110 ). In addition, the light-shielding film 106 may be composed of a single-layer film having a uniform composition, a continuous film having a different composition or composition ratio, and a multi-layer film having different compositions and two or more layers of the films having different compositions one or more times.

The first light-shielding layer 108 and the second light-shielding layer 110 may be formed of any one of molybdenum (Mo), chromium (Cr), tantalum (Ta), vanadium (V), cobalt (Co), nickel (Ni) Zr, niobium, palladium, zinc, aluminum, manganese, cadmium, magnesium, lithium, selenium, (Si), nitrogen (N), oxygen (O), carbon (C), boron (B), and at least one metal element selected from the group consisting of copper (Cu), hafnium (Hf), and tungsten (W) , Fluorine (F), and hydrogen (H).

The first light-shielding layer 108 and the second light-shielding layer 110 are made of a material having a high extinction coefficient k in order to improve the light shielding property. In order to improve the etch rate, an etching gas It is preferable to use a material having a low breaking point (BP).

The first light-shielding layer 108 and the second light-shielding layer 110 may be made of molybdenum chromium (MoCr) or MoCrN containing one of nitrogen (N), oxygen (O), and carbon (C) , MoCrC, MoCrNO, MoCrCN, MoCrCO, and MoCrCON. In addition, in order to reduce the stress of the first light-shielding layer 108 and the second light-shielding layer 110, it may further include additional light elements such as hydrogen (H) and boron (B).

The first light-shielding layer 108 and the second light-shielding layer 110 may be formed to have a molybdenum (Mo) content of 1 at% to 20 at%, preferably 3 at% to 10 at%, and a chromium (Cr) (O) is preferably 0 to 50 at%, more preferably 40 at% or less, and the carbon (C) is 0 to 50 at%, preferably at 20 at% to 70 at% To 30 at%, preferably 20 at% or less.

The light shielding film 106 has an optical density (OD) per unit thickness when molybdenum (Mo) has a higher extinction coefficient (k) than that of chromium (Cr) ) Is increased to make the light-shielding film thinner. When the light-shielding film 106 includes molybdenum (Mo), the dry etching of the light-shielding film 106 formed of molybdenum chromium (MoCr) compound causes a chlorine (Cl) gas as compared to a conventional chromium The etching rate can be remarkably increased. However, when the content of molybdenum (Mo) in the light-shielding film 106 is high, the chemical resistance against the cleaning chemical used in manufacturing the photomask is deteriorated, The content of molybdenum (Mo) in the second light-shielding layer 110 is preferably controlled to 20 at% or less.

The first light shielding layer 108 and the second light shielding layer 110 may be formed of tantalum (Ta), vanadium (V), cobalt (Co), nickel (Co) Ni, zirconium, niobium, palladium, zinc, aluminum, manganese, cadmium, magnesium, lithium, selenium, (B), fluorine (F), and hydrogen (H), one or more metal elements selected from the group consisting of Se, Cu, Hf, and W.

The light shielding film 106 may be formed by various methods using a physical or chemical vapor deposition method, for example, using a DC magnetron sputtering apparatus. When the light shielding film 106 is formed of molybdenum chromium (MoCr) or a compound thereof using the sputtering method, the light shielding film 106 can be formed using a single molybdenum chromium (MoCr) target. At this time, the molybdenum chromium (MoCr) single target has a composition ratio of molybdenum (Mo): chromium (Cr) = 1 at% to 30 at%: 70 at% to 99 at%. The light shielding film 106 may be formed by a co-sputtering method using a plurality of targets made of molybdenum (Mo) and chromium (Cr) at the same time.

The first light-shielding layer 108 and the second light-shielding layer 110 may be made of Cr or Cr, CrN, CrO, CrC containing one of nitrogen (N), oxygen (O) , CrNO, CrCN, CrCO, and CrCON. In addition, in order to reduce the stress of the first light-shielding layer 108 and the second light-shielding layer 110, it may further include additional light elements such as hydrogen (H) and boron (B). The first light-shielding layer 108 and the second light-shielding layer 110 may include 30 at% to 70 at% of chromium (Cr), 0 to 40 at% of nitrogen (N), 0 to 50 at% of oxygen (C) is 0 to 30 at%.

The light shielding film 106 has a thickness of 400 ANGSTROM to 700 ANGSTROM, preferably 450 ANGSTROM to 600 ANGSTROM, more preferably 450 ANGSTROM to 550 ANGSTROM.

The first light-shielding layer 108 is used to control the overall optical density and etch rate of the light-shielding film 106 and the second light-shielding layer 110 is used to supplement the optical density and control the surface resistivity . That is, when the optical density is controlled only by the first light-shielding layer 108, the thickness of the first light-shielding layer 108 is increased to satisfy the required light-shielding function, So that the required optical density can be supplemented. Further, the second light-shielding layer 110 is designed so that the content of oxygen (O) in the composition is relatively low so as to lower the high sheet resistance of the first light-shielding layer 108 relatively. Accordingly, the first light shielding layer 108 has a thickness corresponding to 60% to 99% of the entire thickness of the light shielding film 106, and preferably has a thickness corresponding to 70% to 98%. The second light shielding layer 110 has a thickness corresponding to 1% to 40% of the thickness of the light shielding film 106, and preferably has a thickness corresponding to 2% to 30%.

The first light-shielding layer 108 includes at least one of oxygen (O) and nitrogen (N) in order to obtain a fast etch rate when forming the light-shielding film 106 pattern. The second light-shielding layer 110 is formed so that the content of oxygen (O) is relatively lower than that of the first light-shielding layer 108 or nitrogen (N) is relatively higher than that of the first light- ) Is relatively high.

The light shielding film 106 formed by laminating the first light shielding layer 108 and the second light shielding layer 110 has an etching rate of 1.5 to 3.5 ANGSTROM / sec for the etching material, preferably 1.8 ANGSTROM / sec Lt; / RTI > / sec.

The second light-shielding layer 110 is designed to control the surface resistivity, so that the sheet resistance is designed to be lower than the first light-shielding layer 108. For this purpose, the second light-shielding layer 110 may additionally include carbon (C). At this time, the carbon (C) preferably has a content of 1 at% to 30 at%, and when the content of carbon (C) is 30 at% or more, the optical density decreases and the thickness increases relatively.

The light shielding film 106 has an optical density value of 2.5 to 3.5 with respect to an exposure wavelength of 193 nm or 248 nm, and preferably has an optical density value of 2.7 to 3.2. Further, the light-shielding film 106 has a surface reflectance of 10% to 45% with respect to an exposure wavelength of 193 nm or 248 nm, and preferably has a surface reflectance of 20% to 40%.

The light shielding film 106 can be selectively heat treated at a temperature of 100 ° C to 500 ° C to adjust the chemical resistance and flatness. As a method for this purpose, a hot plate, a Vaccum Rapid Thermal Annealing, Plasma treatment can be performed.

In addition, although not shown, the light blocking film 106 may further include an antireflection film provided on one or more of the upper and lower portions of the light blocking film 106 to suppress the re-reflection of the exposure light, if necessary. The antireflection film may be made of chromium (Cr), molybdenum chromium (MoCr) or a compound thereof in the same manner as the light shielding film 106, or may be made of the same material as the light shielding film 106. However, the anti-reflection film may be used as an etching mask for the light-shielding film 106. In this case, the anti-reflection film is made of a material having an etching property different from that of the light-

The hard film 112 may be formed of a material selected from the group consisting of tantalum (Ta), molybdenum (Mo), aluminum (Al), tungsten (W), titanium (Ti), silicon (Si), vanadium (V), cobalt Ni, Zr, Nb, Pd, Zn, Mn, Cd, Mg, Li, Selenium, (N), oxygen (O), carbon (C), boron (B), fluorine (F) or the like is added to the metal material, ), And hydrogen (H).

The hard film 112 is used as an etching mask for the lower light-shielding film 106 after pattern formation, and the light-shielding film pattern formed by the etching process is used as an etching mask for the phase reversal film 104. The hard film 112 according to the present invention is composed of a material which is etched into the same etching material as the phase reversal film 104 so that the hard film 112 is removed during the pattern formation of the phase reversal film 104. Therefore, it is preferable that the hard film 112 is made of one of tantalum (Ta) compounds such as tantalum (Ta), TaO, TaN, TaC, TaON, TaCN, TaCO, TaCON.

On the other hand, if the etching rate of the hard film 112 is high, all the hard films 112 are removed during the etching process of the phase reversal film 104 to expose the light shielding film 106 located at the bottom. At this time, the pattern of the exposed light shielding film 106 is damaged by the etching material of the phase reversal film 104, so that the optical characteristics of the light shielding film 106 may be deteriorated.

Thus, the hard film 112 according to the present invention is configured to have an etch rate that can all be eliminated to suit the etch process of the phase reversal film 104. [ The hard film 112 is preferably formed of one of tantalum oxide (TaO), tantalum oxynitride (TaON), and oxynitride tantalum oxide (TaCON) containing oxygen (O) And has a content of 30 at%. The hard film 112 made of tantalum (Ta) as a main component has a small amount of oxygen (O) to be contained in the conventional silicon (Si) oxide film, It is possible to improve the problem of increasing the sheet resistance due to the addition of (O). At this time, in order to reduce the stress of the hard film 112, it may further include additional light elements such as hydrogen (H) and boron (B).

The hard film 112 may include at least one light element selected from the group consisting of nitrogen (N), oxygen (O), carbon (C), boron (B), fluorine (F) Silicon (Si) compound. Hard film 112 contains less than 60 at% silicon (Si), preferably less than 50 at% silicon. When the content of silicon (Si) is 60 at% or more, the etching rate of the hard film 112 is increased. As a result, the hard film is removed in the phase reversal film pattern forming process, Causing damage.

The hard film 112 has a thickness of 20 ANGSTROM to 100 ANGSTROM and preferably has an etching rate lower than the etching rate of the phase reversal film 104 in order to prevent the damage of the lower shielding film 106 pattern. The hard film 112 has an etching rate of 1/3 or less of the etching rate of the phase reversal film 104, and preferably has an etching rate of 1/5 or less.

Hereinafter, a blank mask according to an embodiment of the present invention will be described in detail.

(Example)

Phase Inversion Blank Mask and Photomask Formation with TaON Hard Film

In order to evaluate a hard film according to an embodiment of the present invention, a DC magnetron reactive sputtering apparatus using a molybdenum silicide (Mo: Si = 1: 9) target on a transparent substrate was used to form a two- Phase reversed film was formed. At this time, the phase reversal film was formed to a thickness of 650 ANGSTROM and exhibited a transmittance of 6% and a phase reversal amount of 180 DEG with respect to a 193 nm wavelength exposure light.

A chromium (Cr) target was used on the phase reversal film to form a light-shielding film having a two-layer structure consisting of a CrN lower layer and a CrON upper layer. At this time, the light shielding film was formed to a thickness of 490 ANGSTROM. The transmissivity was 0.08% at the surface of the laminated structure of the phase reversal film and the light shielding film, and the optical density was 3.09.

A hard film made of TaON was formed to a thickness of 40 angstroms using a tantalum (Ta) target on the phase reversal film and a process gas of 5 sccm: 5 sccm: ₂ sccm of Ar: N ₂ : NO = Thick. The compositional ratio of the hard film was analyzed using AES equipment, and it was Ta: N: O = 58 at%: 30 at%: 12 at%.

A negative chemical amplification type resist (Nega CAR) film having a thickness of 800 Å was formed on the hard film to complete the final blank mask.

The resist film of the blank mask was exposed using an ion beam (e-beam) exposure equipment, and then a post exporse bake process was performed at a temperature of 190 ° C for 10 minutes and a development process was performed to form a resist film pattern Respectively. In order to confirm the problem of adhesion to the resist film pattern, the pattern cross-section was measured using an FE-SEM, and no problem such as pattern collapse occurred.

The hard film was etched with an etching gas based on a fluorine (F) gas using the resist film pattern as an etching mask to form a hard film pattern. At this time, etching of the hard film was performed for 60 seconds by applying an over-etch, and the etching rate was measured by EPD (End Point Detection). As a result, the hard film exhibited an etching rate of 1.3 A / sec .

The resist film was removed, and a light-shielding film pattern was formed by etching a hard film pattern made of TaON with an etching mask and an underlying light-shielding film with an etching gas based on chlorine (Cl) gas. At this time, the change of the thickness of the hard film pattern was measured by AFM apparatus, and it was confirmed that there was no problem in the aspect ratio of the light shielding film and etch selectivity.

The phase reversal film under the light shielding film pattern was etched with an etching gas using a fluorine (F) gas to form a phase reversal film pattern. At this time, the etching of the phase reversal film was carried out by applying over-etch of 30%, and the etching rate was measured by EPD. As a result, the phase reversal film exhibited an etching rate of 13.5 Å / sec.

The hard film pattern made of TaON was all removed in the etching process for forming the phase reversal film pattern, and the thickness variation of the lower light-shielding film pattern was measured to be 2.3 ANGSTROM. The optical density (OD) was measured The result was 0.01 or less, and it was confirmed that there was no influence on the optical characteristics.

A resist film pattern was formed on the patterns and a part of the light-shielding film pattern was removed to complete the fabrication of the final photomask.

Evaluation of etching rate according to composition of TaON hard film

The composition of the hard film made of TaON was changed to evaluate the etch rate of the hard film against the etching rate of the phase reversal film and the damage of the light shielding film generated at this time.

Example 1 Example 2 Example 3 Example 4 Example 5

Hard film
(Ta)
Process gas ratio
(Ar: N _2: NO) 5: 5: 2 5: 5: 3 5: 5: 5 5: 5: 8 5: 5: 20 thickness 40 Å 40 Å 40 Å 40 Å 40 Å Composition ratio
(Ta: N: O) 58: 30: 12 56: 28: 16 52: 25: 23 51: 24: 28 49: 19: 32 Sheet resistance 384Ω / □ 483Ω / □ 682Ω / □ 832 Ω / □ 1.5kΩ / □ Etching rate 1.3 A / sec 1.8 A / sec 2.2 A / sec 2.5 A / sec 6.2 A / sec
Phase reversal film
(MoSi) thickness 650 Å 650 Å 650 Å 650 Å 650 Å Etching rate 13.5 A / sec 13.5 A / sec 13.5 A / sec 13.5 A / sec 13.5 A / sec Etching time
(w / o 30%) 65 sec 65 sec 65 sec 65 sec 65 sec Shading film damage 2.3 Å 3.2 Å 4.0 Å 4.5 Å 15.2 Å

Table 1 shows the hardness of the hard film and the damage of the light-shielding film at the time of forming the hard film by changing the composition of the process gas when forming the hard film made of TaON, and comparing the etch rate of the phase reversal film.

Referring to Table 1, it can be seen that in the embodiments, the etching rate is increased as the content of oxygen (O) increases in the hard film made of TaON, and thus the degree of damage of the light shielding film is large when the phase reversal film is etched.

That is, in the case of Examples 1 to 4, the damage of the light-shielding film was insignificantly less than 4.5 ANGSTROM, whereas in Example 5, the damage of the light-shielding film was 15.2 ANGSTROM, .

In addition, the sheet resistance of the hard film increased as the content of oxygen (O) increased. In particular, in Example 5, the sheet resistance value was 1.5 kΩ / □, but it is not a big problem when the correction value in the exposure equipment is considered . However, high sheet resistance values in terms of process window margins are analyzed as relatively poor results because they can cause charge-up phenomena.

Phase Inversion Blank Mask and Photomask Formation with SiON Hard Film

In order to evaluate the SiON hard film according to the embodiment of the present invention, a phase reversal film, a light-shielding film and a hard film were formed on a transparent substrate. The phase reversal film and the light shielding film were formed to have the same composition and composition as those of the film of the phase inversion blank mask provided with the TaON hard film described above.

A silicon (Si) target doped with boron (B) was used for forming a hard film on the phase reversal film, and a process gas was implanted with Ar: NO: N ₂ = 5 sccm: 10 sccm: 2 sccm, A 40 Å thick SiON film was formed using the process power. The compositional ratio of the hard film was analyzed using AES equipment, and as a result, Si: N: O = 50 at%: 12 at%: 38 at%. In addition, when the sheet resistance of the hard film was measured using a 4-point probe, the sheet resistance was 1.2 k? /?, Indicating a high sheet resistance for the TaON hard film.

Then, a negative chemical amplification type resist (Nega CAR) film having a thickness of 800 Å was formed on the SiON hard film to complete the final blank mask.

The resist film of the blank mask was exposed using an ion beam (e-beam) exposure equipment, and then a post exporse bake process was performed at a temperature of 190 ° C for 10 minutes and a development process was performed to form a resist film pattern Respectively. In order to confirm the problem of adhesion to the resist film pattern, the pattern cross-section was measured using an FE-SEM, and no problem such as pattern collapse occurred.

The hard film was etched with an etching gas based on a fluorine (F) gas using the resist film pattern as an etching mask to form a hard film pattern. At this time, etching of the hard film was performed for 60 seconds by applying Over Etch. The etching rate was measured by EPD (End Point Detection). As a result, the hard film showed an etching rate of 2.0 Å / sec .

The resist film was removed, and a light-shielding film pattern was formed by etching a hard film pattern made of SiON with an etching mask and an underlying light-shielding film with an etching gas based on chlorine (Cl) gas. At this time, the change of the thickness of the hard film pattern was measured using the AFM equipment, and it was found to be 1.7 Å.

The phase reversal film under the light shielding film pattern was etched with an etching gas using a fluorine (F) gas to form a phase reversal film pattern. At this time, the etching of the phase reversal film was carried out by applying over-etch of 30%, and the etching rate was measured by EPD. As a result, the phase reversal film exhibited an etching rate of 13.5 Å / sec.

The hard film pattern made of SiON was removed in the etching process for forming the phase reversal film pattern, and the thickness variation of the lower light-shielding film pattern was measured to be 3.8 Å. The optical density (OD) was measured The result was 0.01 or less, and it was confirmed that there was no influence on the optical characteristics.

A resist film pattern was formed on the patterns and a part of the light-shielding film pattern was removed to complete the fabrication of the final photomask.

Evaluation of etching rate according to composition of SiON hard film

The composition of the hard film made of SiON was changed to evaluate the etch rate of the hard film against the etching rate of the phase reversal film and the damage of the light shield film occurring at this time.

Example 6 Example 7 Example 8 Example 9 Example 10

Hard film
(Si)
Process gas ratio
(Ar: N _2: NO) 5: 2: 10 5: 2: 9 5: 2: 8 5: 2: 2 5: 2: 15 thickness 40 Å 40 Å 40 Å 40 Å 40 Å Composition ratio
(Si: N: O) 50: 12: 38 51: 14: 35 52: 15: 37 68: 18: 14 41: 10: 49 Sheet resistance 1.2㏀ / □ 1.1㏀ / □ 1.0 ㏀ / □ 0.6 ㏀ / □ 2.5kΩ / □ Etching rate 2.0 A / sec 2.08 A / sec 2.20 A / sec 8.2 A / sec 1.5 A / sec
Phase reversal film
(MoSi) thickness 650 650 Å 650 Å 650 Å 650 Å Etching rate 13.5 A / sec 13.5 A / sec 13.5 A / sec 13.5 A / sec 13.5 A / sec Etching time
(w / o 30%) 65 sec 65 sec 65 sec 65 sec 65 sec Shading film damage 3.8 Å 3.8 Å 4.1 Å 20.4 Å 1.2 Å

Table 2 shows the etching rate of the hard film and the damage of the light-shielding film occurring at the time of forming the hard film by changing the composition of the process gas when forming the hard film made of SiON and comparing the etching rate of the phase reversal film.

Referring to Table 2, in the hard films made of SiON in Examples 6 to 10, it was confirmed that as the content of oxygen (O) was increased, the etching rate was slowed and thus the damage of the light shielding film was reduced in the etching of the phase reversal film I could.

That is, in the case of Examples 6 to 8 and Example 10, the damage of the light-shielding film was insignificantly less than 4.1 ANGSTROM, whereas in Example 9, the damage of the light-shielding film was 20.4 ANGSTROM, And it was confirmed that it was difficult to apply.

On the other hand, in the case of the hard film, the sheet resistance increased as the content of oxygen (O) increased. Particularly, in Example 10, the sheet resistance value showed 2.5 k? / Sq. . However, high sheet resistance values in terms of process window margins are analyzed as relatively poor results because they can cause charge-up phenomena.

100: Phase inversion blank mask
102: transparent substrate 104: phase reversal film
106: light shielding film 108: first light shielding film
110: second light-shielding film 112: hard film
114: resist film

Claims (19)

A transparent substrate; And
A phase shift film, a light shield film, and a hard film sequentially stacked on the transparent substrate,
Wherein the hard film comprises a metal oxide.
The method according to claim 1,
The hard film may be made of at least one of tantalum (Ta), molybdenum (Mo), aluminum (Al), tungsten (W), titanium (Ti), silicon (Si), vanadium (V), cobalt (Co) Zr, Nb, Pd, Zn, Mn, Cd, Mg, Li, Selenium, Cu, , Hafnium (Hf), and tin (Sn).
Or wherein the metal material further comprises at least one light element selected from nitrogen (N), oxygen (O), carbon (C), boron (B), fluorine (F) Blank mask.
The method according to claim 1,
Wherein the hard film is composed of a tantalum (Ta) compound further comprising at least one light element selected from nitrogen (N), oxygen (O), carbon (C), boron (B), fluorine (F) Wherein the phase inversion blank mask is a phase shift mask.
The method according to claim 1,
The hard film is composed of a tantalum (Ta) compound containing oxygen (O)
Wherein the oxygen (O) has a content of 1 at% to 30 at%.
A transparent substrate; And
A phase shift film, a light shield film, and a hard film sequentially stacked on the transparent substrate,
Wherein the hard film comprises silicon (Si) oxide.
6. The method of claim 5,
Wherein the hard film is made of a silicon (Si) compound further comprising at least one light element selected from nitrogen (N), oxygen (O), carbon (C), boron (B), fluorine (F) Wherein the phase inversion blank mask is a phase shift mask.
6. The method of claim 5,
The hard film is composed of a silicon (Si) compound containing oxygen (O)
Wherein the silicon (Si) has a content of 60at% or less.
6. The method according to claim 1 or 5,
Wherein the hard film comprises a material that is etched into the same etch material as the phase reversal film.
6. The method according to claim 1 or 5,
Wherein the hard film has an etch rate that can all be removed to suit the etching process of the phase reversal film.
6. The method according to claim 1 or 5,
Wherein the etching rate of the hard film has an etching rate of 1/3 or less of the etching rate of the phase reversal film.
6. The method according to claim 1 or 5,
Wherein the hard film has a thickness of 20 ANGSTROM to 100 ANGSTROM.
6. The method according to claim 1 or 5,
Wherein the light-shielding film comprises a first light-shielding layer and a second light-shielding layer,
A method of manufacturing a semiconductor device, which further comprises at least one light element selected from the group consisting of nitrogen (N), oxygen (O), carbon (C), boron (B), fluorine (F), and hydrogen (H) in chromium (Cr) or molybdenum Wherein the phase inversion blank mask is made of a metal compound.
13. The method of claim 12,
The first light shielding layer is formed to a thickness corresponding to 60% to 99% of the total thickness of the light shielding film,
Wherein the second light-shielding layer has a higher optical density per unit thickness (A) than the first light-shielding layer.
13. The method of claim 12,
Wherein the light-shielding film has an etching rate of 1.5 A / sec to 3.5 A / sec.
13. The method of claim 12,
Wherein the light-shielding film has a thickness of 400 ANGSTROM to 700 ANGSTROM.
6. The method according to claim 1 or 5,
Wherein the phase reversal film is formed of at least one element selected from the group consisting of nitrogen (N), oxygen (O), carbon (C), boron (B), fluorine (F) and hydrogen (H) in silicon (Si) or molybdenum Further comprising: a phase inversion blank mask.
17. The method of claim 16,
Wherein the phase reversal film is composed of a single layer film having a uniform composition, a continuous film having a different composition or composition ratio, and a multilayer film having two or more different compositions and having two or more layers laminated one or more times. Mask.
17. The method of claim 16,
Wherein the phase reversal film has a transmittance of 5% to 40% with respect to exposure light having a wavelength of 193 nm or 248 nm.
A phase inversion photomask formed using the blank mask of claim 1 or 5.

Images