JP6557381B1 - Phase reversal blank mask and photomask - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a phase inversion blank mask and a photomask. A phase inversion film according to the present invention comprises films having different compositions that can be etched in the same etching solution, and films having different compositions are laminated at least once. It is formed in the form of a multilayer film or a continuous film of at least two layers. As a result, the present invention can reduce the thickness of the phase inversion film, and can sharpen the cross section of the edge so that the boundary of the phase inversion film pattern becomes clear when patterning the phase inversion film. Uniformity of the transmittance of the film pattern and the phase inversion amount can be ensured, and therefore a phase inversion blank mask and a photomask with improved pattern accuracy of the phase inversion film pattern and the transfer target can be provided. . [Selection] Figure 1

Description

  The present invention relates to a phase inversion blank mask and a photomask, and more particularly, to a phase inversion blank mask capable of improving the pattern accuracy of a transfer object using a phase inversion phenomenon in exposure light having a composite wavelength in the range of 290 nm to 450 nm. It relates to a photomask.

  In a lithography process for manufacturing a flat panel display (hereinafter referred to as FPD) device including a TFT-LCD, an OLED, a PDP, or the like or a semiconductor integrated circuit device, a photomask manufactured from a blank mask is commonly used. The used pattern is transferred.

  A blank mask is obtained by forming a thin film containing a metal material on the main surface of a translucent substrate made of synthetic quartz glass or the like, and forming a resist film on the thin film. The thin film is patterned from the mask. Here, the thin film can be classified into a light shielding film, an antireflection film, a phase inversion film, a semi-transparent film, a hard film, and the like according to optical characteristics. Including thin films may be used.

  Recently, as the market demand for FPD products has become higher-grade and higher-functionality, its application range has been expanded, and development of excellent manufacturing process technology is required. That is, high pattern resolution and high precision technology are required for FPD devices as well as highly integrated semiconductor devices for high integration.

  Therefore, as a method for improving the precision of a photomask for manufacturing an FPD device, an FPD phase inversion blank having a phase inversion film whose phase is inverted by about 180 ° with respect to exposure light of a composite wavelength even in a unity exposure apparatus. Masks and photomasks have been developed. The phase inversion film is a thin film formed of a molybdenum silicide (MoSi) compound or a chromium (Cr) compound, and the thin film formed on a large-area substrate is manufactured in a pattern form using wet etching.

  The phase inversion film composed of the molybdenum silicide (MoSi) compound or the chromium (Cr) compound has an isotropic etching characteristic at the time of wet etching suitable for a large area. The etching cross section has a gentle slope. Such inclination of the edge of the pattern causes a difference in transmittance and phase inversion amount between the edge of the pattern and other portions, and affects the uniformity of the line width of the phase inversion film pattern. In addition, the boundary of the phase inversion film becomes unclear due to the inclination of the phase inversion film at the edge of the pattern, making it difficult to form a fine pattern.

  On the other hand, when the reflectance of the phase inversion film is high, it is difficult to form a fine pattern due to the interference effect between the surface reflection light of the thin film and the exposure light during the printing process, and low reflectance characteristics with respect to the exposure light are required. Yes.

  An object of the present invention is to provide a phase inversion blank mask and a photomask that are excellent in the cross-sectional inclination of the edge of the phase inversion film pattern. As a result, the uniformity of the transmittance and the phase amount in the edge region of the pattern is improved, and the accuracy and uniformity of the phase inversion film pattern and the pattern line width of the transferred object are finally improved. Can do.

  Another object of the present invention is to provide a phase reversal blank mask capable of improving the fine pattern precision of a transferred object by reducing the surface reflectivity of the phase reversal film and preventing the generation of interference waves due to the surface reflected light. And providing a photomask.

  The phase inversion blank mask according to the present invention is provided with a phase inversion film on a transparent substrate, and the phase inversion film is composed of at least two multilayer films made of metal silicide, and is the uppermost layer of the multilayer films. The film has a higher content of nitrogen (N) than at least one film provided in the lower part.

  The film constituting the phase inversion film is made of one of compounds including molybdenum silicide (MoSi) or molybdenum silicide (MoSi) containing one or more of oxygen (O), nitrogen (N), and carbon (C).

  In the film constituting the phase inversion film, the content of nitrogen (N) is equal or lower as it goes from the uppermost layer film to the transparent substrate.

  The phase inversion film is etched into an etching solution mainly composed of ammonium hydrogen fluoride (NH4) HF2, hydrogen peroxide (H2O2), and pure water (DI-water).

  The ammonium hydrogen fluoride ((NH 4) HF 2) is contained at 10 vol% or less with respect to the entire etching solution.

  The phase inversion film has a reflectance of 35% or less, a transmittance of 1% to 40%, a phase inversion amount of 140 ° to 220 °, and a phase of 60 ° or less with respect to exposure light having a composite wavelength in the range of 290 nm to 450 nm. Has a quantity deviation.

  According to the present invention, the phase inversion film has a multilayer film structure of two or more layers, and each film can be configured as a single film or a continuous film. Further, when the phase inversion film is formed, the cross-sectional shape of the edge of the pattern and the surface reflectance can be controlled by controlling the contents of oxygen, nitrogen, and carbon contained in each layer.

  As a result, it is possible to manufacture a phase inversion blank mask and a photomask that are excellent in the cross-sectional shape of the edge of the phase inversion film pattern. As a result, the uniformity of the transmittance and the phase amount in the edge region of the pattern can be improved, and the precision and uniformity of the phase inversion film pattern and the pattern line width of the transferred object can be improved finally. .

  In addition, according to the present invention, the phase inversion blank mask can improve the fine pattern precision of the transfer target by reducing the surface reflectance of the phase inversion film and preventing the generation of interference waves due to the surface reflected light. And a photomask can be manufactured.

It is sectional drawing which shows the phase inversion blank mask which concerns on the 1st Embodiment of this invention. It is sectional drawing which shows the phase inversion film | membrane which concerns on embodiment of this invention. It is sectional drawing shown in order to demonstrate the manufacturing method and phase inversion photomask of the phase inversion photomask which concern on the 1st Embodiment of this invention. It is sectional drawing shown in order to demonstrate the manufacturing method and phase inversion photomask of the phase inversion photomask which concern on the 1st Embodiment of this invention. It is sectional drawing shown in order to demonstrate the manufacturing method and phase inversion photomask of the phase inversion photomask which concern on the 1st Embodiment of this invention. It is sectional drawing shown in order to demonstrate the manufacturing method and phase inversion photomask of the phase inversion photomask which concern on the 1st Embodiment of this invention. It is sectional drawing shown in order to demonstrate the manufacturing method and phase inversion photomask of the phase inversion photomask which concern on the 1st Embodiment of this invention. It is sectional drawing shown in order to demonstrate the manufacturing method and phase inversion photomask of the phase inversion photomask which concern on the 1st Embodiment of this invention. It is sectional drawing which shows the phase inversion photomask which concerns on the 2nd Embodiment of this invention. It is sectional drawing which shows the phase inversion blank mask which concerns on the 3rd Embodiment of this invention. It is sectional drawing which shows the interface of the phase inversion film which concerns on this invention. It is a graph which shows the reflectance and the transmittance | permeability which concern on the Example of this invention. 3 is a photograph showing a cross section of a photomask pattern according to an embodiment of the present invention. 5 is a graph showing the reflectance and transmittance according to Comparative Example 1. 6 is a photograph showing a cross section of a photomask pattern according to Comparative Example 1. 10 is a graph showing the reflectance and transmittance according to Comparative Example 2. 10 is a photograph showing a cross section of a photomask pattern according to Comparative Example 2.

  Hereinafter, the present invention will be described in detail with reference to the drawings with reference to examples of the present invention. However, the examples are merely for illustrating and explaining the present invention, meaning limitations and patents. It is not intended to limit the scope of the invention as recited in the claims. Accordingly, those skilled in the art in the technical field of the present invention can understand that various modifications and other equivalent embodiments can be made from the embodiments. Therefore, the true technical capability protection scope of the present invention should be determined by the technical matters of the claims.

  Hereinafter, a phase inversion blank mask and a photomask embodied in an embodiment of the present invention are for FPD devices and semiconductors including a liquid crystal display (LCD), a plasma display panel (PDP), an organic light emitting diode (OLED), etc. A phase inversion blank mask and a photomask for manufacturing a device. The exposure light indicates a composite wavelength in the range of 290 nm to 450 nm.

  FIG. 1 is a sectional view showing a phase inversion blank mask according to the first embodiment of the present invention, and FIG. 2 is a sectional view showing a phase inversion film according to the embodiment of the present invention.

  Referring to FIG. 1, a phase inversion blank mask 100 according to the present invention has a structure in which a phase inversion film 104, a light shielding film 110, and a resist film 114 are sequentially stacked on a transparent substrate 102.

  The transparent substrate 102 is, for example, a rectangular transparent substrate having a side of 300 mm or more, and may be a synthetic quartz glass, a soda lime glass substrate, an alkali-free glass substrate, a low thermal expansion glass substrate, or the like.

  Referring to FIG. 2, the phase inversion film 104 includes at least two thin films 104a,. . . , 104n are stacked, preferably 2 to 10 layers, more preferably 2 to 8 layers.

  Each thin film 104a,. . . , 104n are made of metal silicide alone or a compound containing at least one light element material of oxygen (O), nitrogen (N), carbon (C), boron (B), and hydrogen (H) in the metal silicide. .

  The metal component in the metal silicide and the compound is aluminum (Al), cobalt (Co), tungsten (W), molybdenum (Mo), vanadium (V), palladium (Pd), titanium (Ti), platinum (Pt ), Manganese (Mn), iron (Fe), nickel (Ni), cadmium (Cd), zirconium (Zr), magnesium (Mg), lithium (Li), selenium (Se), copper (Cu), yttrium (Y ), Sulfur (S), indium (In), tin (Sn), boron (B), beryllium (Be), sodium (Na), tantalum (Ta), hafnium (Hf), niobium (Nb) Comprising one or more of the above.

  In particular, each thin film 104a,. . . , 104n can be made of molybdenum silicide (MoSi) containing molybdenum (Mo) and one or more selected from MoSi, MoSiN, MoSiC, MoSiON, MoSiCN, MoSiCO, and MoSiCON, which are compounds thereof.

  In the molybdenum silicide (MoSi) compound film, molybdenum (Mo) is 2 at% to 30 at%, silicon (Si) is 20 at% to 70 at%, nitrogen (N) is 5 at% to 50 at%, and oxygen (O) is 0 at%. It is preferable that the content of ˜30 at% and carbon (C) is 0% to 30 at%.

  Each thin film 104a,. . . , 104n may be composed of the same composition or may have different compositions of light elements. For example, in the case of a phase inversion film composed of two layers, it may be composed of the same composition such as MoSiN and MoSiN, or may be composed of different compositions such as MoSiN and MoSiON. When the thin films have the same composition, the constituent materials can be formed so as to have different composition ratios.

  Each thin film 104a,. . . , 104n can be in the form of a single film with the same composition and composition ratio, or in the form of a continuous film with varying composition or composition ratio. Here, the continuous film refers to a film formed by changing process variables such as reactive gas, power, pressure, and the like during the sputtering process while the plasma is on.

  Each thin film 104a,. . . 104n have different etching rates and surface reflectivities with respect to the same etching solution depending on variables such as composition, composition ratio, and thickness. In order to make the slope of the cross section steep and adjust the reflectivity, it is properly arranged.

  First, as a method of adjusting the etching rate of the phase inversion film 104 to make the cross-sectional inclination steep, it is preferable to adjust the content of the light element substance. Specifically, among light elements, increasing the nitrogen (N) or carbon (C) content can slow the etching rate, and increasing the oxygen (O) content increases the etching rate. Can be made.

  Further, when the etching rate is adjusted by changing the contents of nitrogen (N) and carbon (C), the phase inversion film thin films 104a,. . . , 104n, the uppermost layer of which has a higher nitrogen (N) or carbon (C) content than at least one of the lower layers, or the upper layer is adjacent to the transparent substrate. It can be configured to have a low nitrogen (N) or carbon (C) content compared to a single film. For example, the content of nitrogen (N) or carbon (C) can be made relatively smaller as it goes from the uppermost thin film to the lower thin film, and the cross-sectional inclination of the edge of the pattern can be made vertical and excellent. .

  On the other hand, in the case of oxygen (O), unlike nitrogen (N) or carbon (C), the uppermost film of the phase inversion film thin film has lower oxygen (O) than at least one of the lower films. It can be configured such that a film having a content or a film adjacent to the transparent substrate has a higher oxygen (O) content than any one of the upper films. For example, the content of oxygen (O) contained in the thin film is increased from the uppermost part to the lower part, so that the cross-sectional inclination of the edge can be made vertical and excellent. On the other hand, in terms of reflectance, the higher the oxygen content of the uppermost thin film, the more the reflectance can be reduced. On the other hand, the reflectivity of the phase inversion film 104 is, in particular, the thin films 104a,. . . , 104n can be adjusted by changing the content of each or both of nitrogen (N) and oxygen (O), and the reflectance can be increased by increasing the content of nitrogen (N) and oxygen (O). Can be lowered. However, oxygen (O) is a factor that increases the etching rate, and because it has a larger effect on increasing the etching rate than on the effect of reducing the reflectance, it becomes a factor that the cross-sectional inclination of the edge becomes gentle and worse. obtain. Therefore, the thin films 104a,. . . 104n is controlled to be 30 at% or less, preferably 20 at% or less, and its thickness is preferably controlled to 30 nm or less.

  Therefore, the thin films 104a,. . . 104n are thin films 104a,... 104n, which are limited to the above-mentioned etching characteristics of nitrogen (N), carbon (C), and oxygen (O) considering only the etching cross-sectional shape of the phase inversion portion 140 pattern. . . , 104n are preferably arranged in consideration of optical characteristics such as reflectance. That is, the thin films 104a,. . . , 104n, the etching rate due to the difference in the content of nitrogen (N), carbon (C), oxygen (O) contained in the thin film and the change in reflectance, etc. The thin film placed in a specific part is configured so that the etching rate is slower or faster than the thin film placed in the upper part or the lower part, and the thin film is arranged so that the reflectance is high or low. The thin films 104a,. . . 104n can be stacked in various forms to optimize the etching cross section and reflectivity. This is because the thin films 104a,. . . , 104n, the amount of deposition gas containing nitrogen (N), carbon (C), and oxygen (O) that realizes similar or different etching characteristics to the thin film among the deposition gases is appropriately set. By adjusting the thin film 104a,. . . , 104n can be adjusted to the optimum state and the etching rate.

  The phase inversion film has a total thickness of 500 to 1,500 mm, preferably 900 to 1,400 mm. The thin films 104 a,. . . 104n have a thickness of 50 mm to 1,450 mm in consideration of the adhesive force with the films disposed on the upper and lower parts, etching characteristics, and the like.

  The films constituting the phase inversion film can be etched into the same etching solution.

  The etching solution for the phase inversion film is preferably an etching solution mainly composed of ammonium hydrogen fluoride ((NH4) HF2), hydrogen peroxide (H2O2), and pure water (DI-water). Of the main components of the etching solution, ammonium hydrogen fluoride ((NH 4) HF 2) is contained in an amount of 10 vol% or less, preferably 5 vol% or less. This is because the substrate surface may be damaged if the solution content of ammonium hydrogen fluoride ([(NH 4) HF 2]) is 10 vol% or more during etching of the phase inversion film.

  The phase inversion film 104 has a reflectance of 35% or less with respect to exposure light having a composite wavelength in the range of 290 nm to 450 nm. Further, the phase inversion film 104 has the lowest reflectance at one wavelength in the wavelength region of 400 nm to 900 nm, and preferably needs to be controlled so as to be located in the wavelength region of 500 nm to 800 nm.

  The phase inversion film 104 has a transmittance of 1% to 40%, preferably a transmittance of 5% to 20% with respect to exposure light having a composite wavelength in the range of 290 nm to 450 nm. The phase inversion film has a phase inversion amount of 140 ° to 220 ° with respect to exposure light having a composite wavelength in the range of 290 nm to 450 nm, and has a phase inversion amount deviation of 60 ° or less. Here, the transmittance deviation and the phase inversion amount deviation are the difference between the maximum value and the minimum value among the values of the exposure light having a composite wavelength in the range of 290 nm to 450 nm.

  The light-shielding film 110 is disposed on the phase-inversion film 104 and can be used as an etching mask for patterning the phase-inversion film 104 in the form of a pattern when the photomask is manufactured.

  The light-shielding film 110 is made of chromium (Cr), aluminum (Al), cobalt (Co), tungsten (W), molybdenum (Mo), vanadium (V), palladium (Pd), titanium (Ti), platinum (Pt ), Manganese (Mn), iron (Fe), nickel (Ni), cadmium (Cd), zirconium (Zr), magnesium (Mg), lithium (Li), selenium (Se), copper (Cu), yttrium (Y ), Sulfur (S), indium (In), tin (Sn), boron (B), beryllium (Be), sodium (Na), tantalum (Ta), hafnium (Hf), niobium (Nb), silicon (Si) ), Or one or more of nitrogen (N), oxygen (O), and carbon (C) may be added to the metal material. It may comprise in La.

  The light-shielding film 110 is preferably chromium (Cr) alone or a compound containing one or more of oxygen (O), nitrogen (N), and carbon (C), such as CrO, CrN, CrC, CrCN. , CrCO, and CrCON film.

  The light-shielding film 110 is preferably in the form of a multilayer film of two or more layers including the light-shielding film 106 and the antireflection film 108 or a continuous film. When the light shielding film 106 has an antireflection function, the antireflection film 108 is formed. You don't have to.

  The light-shielding film 110 is made of a material that can be etched together in the same etching solution, has a composition or composition ratio different from each other, and is in the form of a multilayer film or a continuous film composed of two or more layers that are laminated one or more times. It is preferable. At this time, the thin films constituting the light-shielding film 110 have different etching rates with respect to the same etching substance depending on variables such as composition, composition ratio, and thickness, and therefore may be appropriately arranged in consideration of these variables.

  The light-shielding film pattern formed by the light-shielding film 110 may be removed after the pattern formation of the phase inversion film 104 disposed below, so that a blind area can be defined at the edge of the substrate. It may remain on a portion of the required phase inversion film pattern.

  The light-shielding film 110 has an optical density of 2 to 6 with respect to exposure light in a single layer structure or a laminated structure with the phase inversion film 104 pattern, and has a thickness of 500 to 2,000 mm. The light-shielding film 110 has a reflectance of 30% or less with respect to exposure light, preferably 20% or less, more preferably 15% or less.

  As described above, the present invention can improve the cross-sectional inclination of the edge of the phase inversion film pattern by making the phase inversion film a multilayer film having different etching rates using molybdenum silicide (MoSi) or a compound thereof. . In addition, the reflectance can be reduced by controlling the content of oxygen and nitrogen in the outermost surface layer.

  Thereby, the CD (Critical Dimension) precision and uniformity of the phase inversion film pattern can be improved, and a fine phase inversion film pattern of 2 μm or less, preferably 1.8 μm or less, more preferably 1.5 μm or less. Can be realized.

  Although not shown, the phase inversion blank mask of the present invention may further include one or more metal films selectively on the upper and lower portions of the phase inversion film or the light-shielding film. Any one of a semi-transmissive film, an etching stopper film, and an etching mask may be used.

  3A to 3F are cross-sectional views for explaining the method of manufacturing a phase-inversion photomask and the phase-inversion photomask according to the first embodiment of the present invention.

  Referring to FIG. 3A, in the phase inversion photomask according to the present invention, a phase inversion blank mask 100 is formed by sequentially laminating a phase inversion film 104, a light shielding film 110, and a resist film 114 on a transparent substrate.

  The phase inversion film 104 and the light shielding film 110 can be formed by a reactive magnetron sputtering method.

  At this time, it is preferable that the phase inversion film 104 and the light shielding film 110 use at least one reactive gas of NO, N 2 O, NO 2, N 2, O 2, CO 2, CO, and CH 4 together. In addition, a gas that can provide oxygen (O), nitrogen (N), and carbon (C) can be freely used.

  When each thin film constituting the phase inversion film 104 is made of molybdenum silicide (MoSi) or a compound thereof, the phase inversion film 104 is a single target of molybdenum silicide (MoSi), or molybdenum (Mo) and silicon (Si). It can form by the sputtering process using the some target which consists of each of these. At this time, the molybdenum silicide (MoSi) single target has a composition ratio of Mo: Si = 2 at% to 30 at%: 70 at% to 98 at%, for example, Mo: Si = 10 at%: 90 at%, Mo: Targets having various composition ratios such as Si = 15 at%: 85 at%, Mo: Si = 20 at%: 80 at%, Mo: Si = 30 at%: 70 at% can be used. It can be freely adjusted according to the required condition of the phase inversion film 104.

  In order to adjust the etching rate of each thin film constituting the phase inversion film 104, the injection ratio of each gas can be made different during the sputtering process, and the reactive gas and the inert gas are 0.5: 9.5 to The injection is finely adjusted at a ratio of 4: 6, preferably 1: 9 to 3: 7.

  The light-shielding film 110 is preferably a laminated form of the light-shielding film 106 and the antireflection film 108, but this is only one exemplary form, and the light-shielding film 110 has two layers in consideration of wet etching characteristics. It can be set as the laminated form of the above multilayer film or a continuous film.

  The light shielding film 110 is formed of a material having an etching selectivity with respect to the phase inversion film 104, and is made of, for example, Cr or any one of chromium (Cr) compounds of CrO, CrN, CrC, CrCO, CrON, CrCN, and CrCON. It is preferable to form.

  Referring to FIG. 3B, the resist film pattern 114a is formed by performing exposure and development processes on the resist film, and then the light-shielding film pattern 110a is etched using the resist film pattern 114a as an etching mask. Form.

  Referring to FIG. 3C, the lower phase inversion film is etched using the resist film pattern and the light-shielding film pattern 110a as an etching mask to form a phase inversion film pattern 104a composed of a multilayer film.

  Although not shown, after the resist film pattern is removed during the above process, the lower phase inversion film is etched using the light-shielding film pattern 110a as an etching mask to form a phase inversion film pattern 104a composed of a multilayer film. You can also

  At this time, the etching process for forming the light-shielding film pattern 110a and the phase inversion film pattern 104a is preferably performed in either a wet or dry etching process, and is preferably performed in a wet etching process. Here, when each thin film constituting the phase inversion film 104 is made of molybdenum silicide (MoSi) or a compound thereof, wet etching is performed using ammonium hydrogen fluoride ((NH 4) HF 2), hydrogen peroxide (H 2 O 2), and pure It is preferable to use an etching solution mainly composed of water (DI-water). In addition, the conventionally well-known various material and method can be used for the etching substance and etching method of the said wet etching process.

  Referring to FIG. 3D, after forming a resist film pattern (not shown) on the light shielding film pattern, an etching process is performed on the light shielding film pattern to form a light shielding film pattern 110b on the phase inversion film pattern 104a. By remaining, the phase-inversion photomask 200 can be manufactured in a rim type (Rim-Type) structure for forming a contact or a line pattern. Accordingly, a side-lobe phenomenon with respect to phase inversion can be prevented.

  Further, referring to FIG. 3E, the phase-inversion photomask 200 in which the light-shielding film pattern 110b remains on the phase-inversion film pattern 104a at the edge so as to define the blind region can be manufactured.

  Referring to FIG. 3F, the phase inversion photomask 200 completely removes the light-shielding film pattern on the phase inversion film pattern 104a after the step of FIG. Only 104a can be produced.

  FIG. 4 is a sectional view showing a phase-inversion photomask according to the second embodiment of the present invention. Referring to FIG. 4, a phase inversion photomask 300 according to the present invention is provided with a phase inversion film pattern 104a formed of a multilayer film of two or more layers in a main area of a transparent substrate 102, and an auxiliary key such as an alignment key in a blind area. At least the light-shielding film pattern 110b is provided so as to have a typical pattern.

  In the phase-inversion photomask 300, a light-shielding film and a resist film pattern are formed on the transparent substrate 102, and then the light-shielding film is etched using the resist film pattern as an etching mask to form a light-shielding film pattern 110b.

  Subsequently, a multilayer phase inversion film is formed on the transparent substrate 102 including the light-shielding film pattern 110b, a resist film pattern is formed on the phase inversion film, and then the phase inversion film is etched to form the phase inversion film pattern 104a. Form.

  Here, although not shown, the light-shielding film pattern 110b can be partially disposed below the required phase-inversion film pattern in the main region.

  The phase inversion blank mask according to the embodiment of the present invention can have a structure including a thin metal film serving as an etching mask for the phase inversion film on a multilayer phase inversion film.

  FIG. 5 is a sectional view showing a phase inversion blank mask according to the third embodiment of the present invention. Referring to FIG. 5, a phase inversion blank mask 400 according to the present invention includes a phase inversion film 204, a metal film 212, and a resist film 214 that are sequentially formed on a transparent substrate 202.

  Here, the phase inversion film 204 has the same structure and physical properties as the phase inversion film in the above-described embodiment in terms of structure, physical, chemical, and optical properties.

  The metal film 212 serves as an etching mask for the phase inversion film 204 in the form of a pattern. For this reason, the metal film 212 is made of a material having an etching selectivity of 10 or more with respect to the etching material for the phase inversion film 204. It is preferable.

  The metal film 212 includes chromium (Cr), aluminum (Al), cobalt (Co), tungsten (W), molybdenum (Mo), vanadium (V), palladium (Pd), titanium (Ti), platinum (Pt), Manganese (Mn), iron (Fe), nickel (Ni), cadmium (Cd), zirconium (Zr), magnesium (Mg), lithium (Li), selenium (Se), copper (Cu), yttrium (Y), Contains one or more metal materials of sulfur (S), indium (In), tin (Sn), beryllium (Be), sodium (Na), tantalum (Ta), hafnium (Hf), niobium (Nb) Or the above substance further contains one or more light element substances of oxygen (O), nitrogen (N), and carbon (C).

  In the case where the phase inversion film 204 is made of a molybdenum silicide (MoSi) compound, the metal film 212 may be, for example, chromium (Cr) alone or chromium (Cr) with oxygen (O), nitrogen (N), carbon (C). It is preferable to comprise a chromium (Cr) compound further including one or more light element substances. At this time, the metal film 212 includes chromium (Cr) of 30 at% to 100 at%, nitrogen (N) of 20 at% to 50 at%, oxygen (O) of 0 at% to 30 at%, and carbon (C) of 0 at% to 30 at%. The composition ratio is%.

  The metal film 212 has a thickness of 10 to 700 mm, preferably 50 to 400 mm. The metal film 212 is excellent in adhesive force with the resist film 214 disposed thereon, and the resist film 214 used as an etching mask for the metal film 212 is thinned because the metal film 212 has a very thin thickness. And has a thickness of 8,000 mm or less, preferably 6,000 mm or less.

  The phase inversion blank mask 400 according to the present embodiment can be made into a phase inversion photomask using the same process as that of the above-described embodiment.

  Here, the phase inversion photomask is also provided with a phase inversion film pattern only on the transparent substrate, as in the above-described embodiment and FIGS. 3D, 3E, 3F, and 4. It can be formed in various forms such as a form in which the metal film pattern remains on a part of the film pattern and a form in which only the phase inversion film pattern remains in the main region.

  As described above, according to the present invention, since the thickness of the resist film can be made much thinner than the conventional one by using a thin metal film as an etching mask for the phase inversion film, the loading effect is remarkably reduced. A metal film pattern with very high precision can be formed after the etching process, and a phase inversion film pattern etched using the metal film pattern as an etching mask can also be formed to have a CD with high precision. .

  In addition, since the metal film has excellent adhesive strength with the resist film, it is fundamentally prevented that the etching substance penetrates from the interface and the cross section of the phase inversion film pattern is inclined when the phase inversion film is patterned. can do.

  Although not shown, the phase-inversion photomask may further include a light-shielding film pattern provided above or below the phase-inversion film pattern for a predetermined role such as a light-shielding function.

  FIG. 6 is a cross-sectional view particularly showing a boundary surface in the phase inversion film pattern according to the embodiment of the present invention. Referring to FIG. 6, the multilayer phase inversion film pattern 104a according to the present invention may be formed so that the etching rate of the lower film is higher than that of the upper film in consideration of variables such as the thickness and the etching rate. By adopting various configurations such as adopting a thin film that slows the etching rate, it is possible to obtain an excellent cross-sectional inclination of the edge of the pattern.

  At this time, the horizontal distance (Tail Size: d) between the upper edge and the lower edge of the phase inversion film pattern 104a is 100 nm or less, preferably 60 nm or less. Further, a straight line connecting the edges of the upper and lower surfaces of the phase inversion film pattern 104a has an angle (θ) of 70 ° to 110 ° with respect to the upper surface, preferably an angle (θ of 80 ° to 100 °). ).

  Note that the phase inversion blank mask and photomask according to the present invention are thin films such as an etching stopper film, a semi-transmission film, and a hard film provided on one or more portions above and below the phase inversion film or the light shielding film. Further can be included.

(Example)
Production and Evaluation of Molybdenum Silicide (MoSi) Compound Multilayer Phase Inversion Film In the embodiment of the present invention, a method for producing a phase inversion blank mask in which a phase inversion film and a light shielding film are sequentially laminated on a transparent substrate will be described.

  First, a synthetic quartz glass substrate having a size of 800 mm × 920 mm was prepared. A three-layered phase inversion film was formed on the substrate using a MoSi [10:90 at%] target with a DC magnetron sputtering apparatus. Specifically, the first layer adjacent to the transparent substrate is formed with Ar: N2 = 90: 18 sccm and a process power of 1.6 kW, and the second layer is formed with Ar: N2 = 90: 22 sccm and a process power of 1.7 kW. The third layer was formed with Ar: N2 = 90: 24 sccm and a process power of 1.75 kW. As a result of measuring the thickness of the phase inversion film deposited as described above, the first layer film was 34.5 nm, the second layer film was 35.2 nm, the third layer film was 33.8 nm, and the total thickness was It was 103.5 nm.

  At this time, referring to FIG. 7 showing the reflectance and transmittance according to the embodiment of the present invention, the transmittance is 4.65% for i line, 7.52% for h line, and 10.10% for g line. The transmittance deviation of the i-h-g line was 5.45%. In the case of the reflectance, 21.45% for the i-line, 22.01% for the h-line, 21.39% for the g-line, and the lowest point was observed at 604 nm.

  On the other hand, in the case of the phase amount, the i-line showed 182 °, the h-line showed 168 °, the g-line showed 153 °, and the phase amount deviation was 29 °.

  After that, a light shielding film having a two-layer structure was formed to a thickness of 105 nm using a chromium (Cr) target, and the optical density was measured after the light shielding film was formed. There was no.

  Thereafter, a resist film was coated on the light-shielding film to a thickness of 500 nm to complete the production of the final phase inversion blank mask.

  A photomask was manufactured using the blank mask manufactured as described above.

  First, a resist film pattern was formed by an exposure and development process using the blank mask, and then the lower light-shielding film pattern was wet etched using the resist film pattern as an etching mask.

  Thereafter, the resist film was removed, and the phase inversion film was further wet etched using the light shielding film pattern. An etching solution composed of ammonium hydrogen fluoride, hydrogen peroxide, and pure water was used as the phase inversion film etching solution. Then, after coating a resist film, exposure and development were performed on the main area excluding the blind area on the outer periphery, and then all of the light-shielding film in the main area was removed to finally complete the production of the photomask.

  The cross-sectional shape of the pattern of the photomask manufactured as described above was measured by FE-SEM, and the angle of the cross-sectional shape (Sidewall angle) was measured. Referring to FIG. 8 showing a cross-sectional photograph of a photomask pattern according to an embodiment of the present invention, it was confirmed that the cross section of the phase inversion film pattern of the photomask had a vertical shape of about 80 ° or more.

(Comparative Example 1)
Production and Evaluation of Molybdenum Silicide (MoSi) Compound Single Layer Phase Inversion Film In Comparative Example 1, a phase inversion film having a single layer structure was produced and evaluated for comparison with the above-described Examples.

  The phase inversion film according to Comparative Example 1 uses the same substrate and equipment as in the above example, uses a MoSi [10:90 at%] target, injects Ar: N 2 = 90 sccm: 24 sccm as a process gas, and the process power is A single phase inversion film was formed to a thickness of 109 nm under the film forming condition of 1.75 kW.

  At this time, referring to FIG. 9 showing the reflectance and transmittance according to Comparative Example 1 of the present invention, the transmittance is 3.55% for i-line, 6.43% for h-line, and 8.38% for g-line. The phase amounts were 190.6 °, 174.1 °, and 162.7 ° for each wavelength, and there was no problem in using it as a phase inversion film for the composite wavelength.

  Then, after forming a light shielding film using a chromium target in the same manner as in the above example, the resist film was also coated to a thickness of 500 nm in the same manner as in the above example to complete the manufacture of the phase inversion blank mask. And after performing the photomask manufacturing process similarly to the said Example, the cross-sectional shape of the pattern of a photomask was measured with FE-SEM, and the angle (Sidewall angle) of the cross-sectional shape was measured.

  At this time, referring to FIG. 10 showing a cross-sectional photograph of the photomask pattern according to Comparative Example 1, the cross-section of the single-layer phase inversion film pattern of the photomask is about 60 ° and has a relatively bad pattern cross-sectional shape. Was confirmed.

(Comparative Example 2)
Production and Evaluation of Multilayer Phase Inversion Film with Molybdenum Silicide (MoSi) Compound Composition In Comparative Example 2, a multilayered phase inversion film is produced by decreasing the ratio of nitrogen (N) toward the top, and a photomask is formed. Then, the cross-sectional shape of the phase inversion film pattern was evaluated.

  For this purpose, the phase inversion film is a three-layer phase inversion film using the same substrate and equipment as in the above example and using a MoSi [10:90 at%] target.

  Specifically, the first layer adjacent to the transparent substrate is Ar: N2 = 50 sccm: 50 sccm, the process power is 1.2 kW, the second layer is Ar: N2 = 90 sccm: 26 sccm, the process power is 1.35 kW, and the third layer is A phase inversion film was manufactured with Ar: N2 = 90 sccm: 18 sccm and a process power of 1.45 kW.

  At this time, referring to FIG. 11 showing the reflectance and transmittance according to Comparative Example 2, the transmittance is 4.35% for the i line, 6.91% for the h line, and 9.27% for the g line. The transmittance deviation of the -hg line was 4.92%, and the phase amount was 181 ° for the i line, 165 ° for the h line, and 151 ° for the g line, showing similar results to the examples.

  However, in terms of reflectivity, due to a decrease in the nitrogen content on the surface, the reflectivity is as high as 30.35% for i-line, 33.33% for h-line, and 33.13% for g-line, which are relatively higher than 30%. The results were higher than those of the examples at all wavelengths.

  Then, after forming a light shielding film using a chromium target in the same manner as in the above example, the resist film was also coated to a thickness of 500 nm in the same manner as in the above example to complete the manufacture of the phase inversion blank mask.

  And after performing the photomask manufacturing process similarly to the said Example, the cross-sectional shape of the pattern of a photomask was measured with FE-SEM, and the angle (Sidewall angle) of the cross-sectional shape was measured.

  At this time, referring to FIG. 12 showing a cross-sectional photograph of the photomask pattern according to Comparative Example 2, the cross-section of the single-layer phase inversion film pattern of the photomask is less than about 30 ° and has a relatively worst pattern cross-sectional shape. I was able to confirm. This is considered to be due to the relatively low content of nitrogen (N) contained in the uppermost layer and the high content of nitrogen (N) contained in the lowermost layer.

  Although the present invention has been described with reference to the preferred embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be readily understood by those skilled in the art that various modifications or improvements can be made to the above embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can also be included in the technical scope of the present invention.

Claims (17)

A phase inversion blank mask in which a phase inversion film is provided on a transparent substrate,
The phase shift layer includes a multilayer film of at least two layers composed of a metal silicide,
The uppermost layer of the multilayer film contains a lot of nitrogen (N) as compared to at least one film provided on the lower part, and
The phase reversal film is a phase reversal blank mask having a transmittance of 1% to 40% with respect to exposure light having a composite wavelength in the range of 290 nm to 450 nm .   The film constituting the phase inversion film is made of molybdenum silicide (MoSi) or one of compounds containing molybdenum silicide (MoSi) containing at least one of oxygen (O), nitrogen (N), and carbon (C). The phase reversal blank mask according to claim 1, wherein:   Metals are aluminum (Al), cobalt (Co), tungsten (W), molybdenum (Mo), vanadium (V), palladium (Pd), titanium (Ti), platinum (Pt), manganese (Mn), iron ( Fe), nickel (Ni), cadmium (Cd), zirconium (Zr), magnesium (Mg), lithium (Li), selenium (Se), copper (Cu), yttrium (Y), sulfur (S), indium ( It includes at least one selected from In), tin (Sn), boron (B), beryllium (Be), sodium (Na), tantalum (Ta), hafnium (Hf), and niobium (Nb). The phase inversion blank mask according to claim 1.   The film constituting the phase inversion film is composed of 2 at% to 30 at% of molybdenum (Mo), 20 at% to 70 at% of silicon (Si), 5 at% to 50 at% of nitrogen (N), and 0 at% of oxygen (O). The phase reversal blank mask according to claim 2, characterized in that it has a content of -30at% and carbon (C) of 0% -30at%.   The films constituting the phase inversion film have the same composition with each other, or have the same composition with each other, and have different composition ratios, or oxygen (O), nitrogen (N), carbon (C The phase reversal blank mask according to claim 1, wherein at least one of (2) has a different composition.   2. The phase inversion blank mask according to claim 1, wherein the film constituting the phase inversion film has an equal or lower content of nitrogen (N) from the uppermost layer film toward the transparent substrate.   The film adjacent to the transparent substrate among the films constituting the phase inversion film has a lower nitrogen (N) content than at least one of the upper films. The phase reversal blank mask as described. Of the film constituting the phase shift layer, the top layer of the film is perforated low oxygen (O) content as compared to any one of the film of at least the lower layer, or a layer adjacent to the transparent substrate upper characterized by having a high oxygen (O) content as compared to any one of the film, the phase inversion blank mask according to claim 1.   Of the films constituting the phase inversion film, when the uppermost film contains oxygen (O), it has an oxygen (O) content of 30 at% or less, and the uppermost film has a thickness of 30 nm or less. The phase reversal blank mask according to claim 8, wherein: Uppermost layer of the film constituting the phase inversion membrane, which have a high carbon (C) content as compared to any one of the film of at least the lower layer, or a layer adjacent to the transparent substrate upper or characterized by having a low-carbon (C) content as compared to a single film, a phase inversion blank mask according to claim 1.   2. The phase according to claim 1, wherein the phase inversion film has a thickness of 500 mm to 1,500 mm, and each film constituting the phase inversion film has a thickness of 50 mm to 1,450 mm. Inverted blank mask.   The phase inversion film is etched into an etching solution containing ammonium hydrogen fluoride (NH4) HF2, hydrogen peroxide (H2O2), and pure water (DI-water) as main components. The phase reversal blank mask according to claim 1, wherein:   The phase reversal blank mask according to claim 12, wherein the ammonium hydrogen fluoride ((NH 4) HF 2) is contained in an amount of 10 vol% or less with respect to the entire etching solution.   2. The phase inversion blank mask according to claim 1, wherein the phase inversion film has a reflectance of 35% or less with respect to exposure light having a composite wavelength in a range of 290 nm to 450 nm.   The phase inversion blank mask according to claim 1, wherein the phase inversion film has a minimum reflectance at any one of wavelengths of 400 nm to 900 nm or less.   The phase inversion film has a phase inversion amount of 140 ° to 220 ° with respect to exposure light having a composite wavelength in a range of 290 nm to 450 nm, and a phase amount deviation of 60 ° or less. The phase reversal blank mask described in 1. 2. The phase according to claim 1, further comprising at least one of a light-shielding film, a semi-transmissive film, an etching stopper film, and an etching mask film provided above or below the phase inversion film. Inverted blank mask.

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