KR20150056435A - Blankmask for Extreme Ultra-Violet Lithography and Photomask using the same - Google Patents

Abstract

In the present invention, disclosed are a blank mask for extreme ultra-violet rays, which is manufactured by consecutively stacking multi-layered reflecting films, capping films, absorption films and resist films on a transparent substrate wherein the absorption film comprises at least one among nickel and nickel-tantal, and a photomask using the same where the accuracy of good pattern is implemented by having hard films when implementing patterns whose level is not more than 14 nm, in particular, and 10 nm by turning resist films into thin films, and the absorption film can be turned into thin films while having an optical property of the absorption film by controlling composition ratio of metal and light elements included in the absorption film.

Description

[0001] The present invention relates to a blank mask for extreme ultraviolet rays and a photomask using the same.

The present invention relates to a blank mask for extreme ultraviolet light using extreme ultra violet (EUV) light of 13.5 nm as an exposure light, and to a photomask for extreme ultraviolet light using the same. More specifically, , A pattern mask of 10 nm or less in pattern accuracy, and a photomask using the blank mask.

Photo-lithography due to the high integration has been developed to improve the resolution, such as 436 nm (g-line), 405 nm (h-line), 365 nm (i-line), 248 nm 193nm (ArF) wavelength is used as exposure light. Recently, lithography technology using EUV exposure light of 13.5nm wavelength has been developed.

However, since the exposure light having a wavelength of 13.5 nm used in EUV lithography is easily absorbed by most substances (including gases), EUV lithography technology can be applied to a conventional transmission type lithography technique (for example, Unlike the principle of using a light source and a light source, a structure for reflecting the exposure light and a structure for absorbing the light are combined. That is, the blank mask for extreme ultraviolet rays is mainly composed of two parts: a multi-reflective layer portion and an absorber layer portion.

Generally, the multilayer reflective film has a structure in which molybdenum (Mo) and silicon (Si) are alternately laminated in 40 to 60 layers and exhibits a reflectance of 64% to 66% at a wavelength of 13.5 nm. The absorbing film is made of a compound containing tantalum (Ta), for example, tantalum nitride (TaN), tantalum nitride (TaON) or the like as a substance capable of absorbing extreme ultraviolet ray exposure light of 13.5 nm. This is because the tantalum (Ta) compound has an advantage that it is easy to perform the mask manufacturing process because plasma etching using chlorine (Cl) and fluorine (F) series radicals widely used in the semiconductor manufacturing process is easy to be.

However, when a pattern of 14 nm or less, particularly 10 nm or less, is implemented by using the above-described absorbing film composed of the tantalum (Ta) compound, the following problems arise.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram illustrating a shadow effect generated in a photomask manufactured using a conventional extreme ultraviolet ray blank mask. FIG.

Referring to FIG. 1, in the extreme ultraviolet ray blank mask for forming the absorption layer 106 with a conventional tantalum (Ta) compound, a shadowing effect due to the thickness of the absorption layer 106 is problematic. The shadow effect refers to the thickness of the absorbing film pattern 106a when the incident angle of the extreme ultraviolet ray exposure light is inclined to the vertical incidence (about 4 to 6 degrees) when the absorbing film pattern 106a is irradiated with extreme ultraviolet ray exposure light. Reflected light is absorbed by the absorbing film pattern 106a and is not transferred to a certain area. In the case where the absorption layer 106 is made of a tantalum (Ta) compound, since the absorption of tantalum (Ta) to extreme ultraviolet ray exposure light is comparatively low, the absorption layer 106 preferably has an extinction coefficient of 70 nm or more As a result, the thickness of the absorbing film 106 becomes thick and the shadow effect also becomes large.

In addition, the thickness of the absorbing film 106 generates the critical number (CD) deviation (Bias) between the patterns (HP-VP) between the horizontal pattern (HP) and the vertical pattern (VP). Particularly, such a characteristic is different from the shadow effect between the horizontal pattern HP and the vertical pattern VP depending on the direction of the pattern (horizontal or vertical) and the direction of the scanner (Scanner).

FIG. 2 is a view for explaining whether or not a shadow effect according to a pattern direction of a photomask manufactured using a conventional extreme ultraviolet ray blank mask is generated.

2 (a) and 2 (b), a shadow effect is generated as described above in the case of the vertical pattern VP. However, in the case of the horizontal pattern HP, the direction of the pattern and the incident light and the reflected light are parallel The shadow effect does not matter. Therefore, a threshold number deviation (CD Bias) is generated between the vertical pattern (VP) and the horizontal pattern (HP).

Accordingly, when the absorption film pattern formed of the tantalum (Ta) compound has a thickness of 70 nm or more, the threshold value deviation between the transverse-longitudinal patterns when applied to a half-pitch 20 nm class is about 4 nm, When applied to the 14-nm class, the threshold number deviation between the horizontal and vertical patterns is about 10 nm or more, and the smaller the pattern size to be implemented, the larger the deviation of the critical dimension.

When the absorbing film is composed of a tantalum (Ta) compound, the absorbing film is generally formed of a two-layer structure (absorbing layer and antireflection layer), and the composition of the material is different from each other. In detail, the absorbing layer (lower layer) constituting the absorbing film is composed of a tantalum nitride film (TaN) having a high extinction coefficient for absorbing the exposure light of 13.5 nm, and the antireflection layer (upper layer) (TaON) film in order to improve the inspection sensitivity in the case of a high sensitivity (257 nm), the etch characteristics are different from each other. For example, a tantalum oxynitride film (TaON) used as an antireflection layer has a high etching property to fluorine gas, and a tantalum nitride film (TaN) has a high etching property to chlorine gas. Therefore, the absorption layer composed of the tantalum (Ta) compound is subjected to the etching process twice by the fluorine gas and the chlorine gas, so that the process is troublesome and the probability of occurrence of defects and foreign matter in the process is high. Ultimately, this problem affects product yield.

Meanwhile, a manufacturing process of a photomask for extreme ultraviolet rays using a blank mask for extreme ultraviolet rays is performed by using a sub-resolution feature size (SRFS) for optical proximity correction (OPC), for example, Assist bar) and the like. The auxiliary pattern is a pattern which is not printed on a wafer but appears on a photomask, and a high resolution is required in addition to a main pattern in manufacturing a photomask. If the resist film is thick when electron beam (e-beam) writing is performed on the extreme ultraviolet ray blank mask, it is difficult to realize a fine pattern by scattering electrons. Therefore, do.

The present invention provides a blank mask for extreme ultraviolet rays having excellent pattern accuracy when a pattern having a hardness of 14 nm or less, particularly 10 nm or less, is formed through thinning of a resist film, and a photomask using the same.

Also, the present invention provides a photomask for extreme ultraviolet rays, which realizes thin film formation of an absorbing film while securing optical characteristics of a required absorbing film by adjusting the composition ratio of metal and light source constituting the absorbing film.

In addition, the present invention provides a high-quality ultraviolet photomask which minimizes etching damage to other films in the etching process of each film by differentiating etch characteristics of the hard film and the absorbing film.

A blank mask according to the present invention is provided with a multilayer reflective film, a capping film, an absorbing film and a resist film on a transparent substrate, and the absorbing film comprises at least one of nickel (Ni) and nickel tantalum (NiTa).

A blank mask according to the present invention is characterized in that a reflective film, a capping film, an absorbing film, a first functional film, and a resist film are sequentially formed on a transparent substrate, and the absorbing film is formed of at least one of nickel (Ni) and nickel tantalum And the first functional film serves as an etching mask for patterning the absorbing film.

The blank mask according to the present invention includes a transparent substrate, a reflective film, a capping film, an absorptive film composed of an absorber layer and a second functional film, and a resist film sequentially formed on the transparent substrate, wherein the absorber layer comprises nickel (Ni) and nickel tantalum (NiTa) And the second functional film functions as an etching mask for patterning the absorber layer and an antireflection layer remaining on the absorber layer.

In addition, the blank mask according to the present invention is characterized by comprising a transparent substrate, a reflective film, a capping film, an absorbing layer consisting of an absorbing layer and a second functional film, a third functional film and a resist film sequentially, Nickel tantalum (NiTa), and the second functional film functions as an etching mask for patterning the absorber layer and as an antireflective layer to remain on the upper portion of the absorber layer, and the third functional film serves as the second And serves as an etching mask for patterning the functional film.

Wherein the absorbent layer and the absorbent layer further comprise at least one light element material selected from the group consisting of oxygen (O), nitrogen (N), carbon (C), and boron (B) The composition ratio of the light source is 99at%: 1at% ~ 20at%: 80at%.

When the absorption layer is formed of nickel tantalum (NiTa), the composition ratio of the nickel tantalum (NiTa) target has a composition ratio of Ni: Ta = 5 at% to 95 at%: 95 at% to 5 at%.

The absorbing film or the lamination of the absorbing layer and the second functional film has a thickness of 30 nm to 70 nm.

The absorbing film or the absorbing film has a film of uniform composition or a single layer film or multilayer structure having a continuous film shape in which the composition ratio is continuously changed.

Wherein the first functional film or the second functional film is made of at least one material selected from the group consisting of Cr (Cr), Ta (Ta), Molybdenum (Mo) and Si (Si) Wherein the composition ratio of the light source to the material is 100 at%: 0 at% to 20 at%: 80 at% (inclusive), and at least one element selected from the group consisting of carbon (C), boron (B) %to be.

The first functional film, the second functional film, or the third functional film has a single film or a single-layer film having a continuous film shape in which the composition ratio is continuously changed or a multilayer structure of two or more layers.

The first functional film, the second functional film, or the third functional film has an etch ratio of 10 or more with respect to the absorbing film, the absorbing layer, or the second functional film disposed below.

The first functional film or the third functional film has a thickness of 1 nm to 10 nm.

The second functional film has a thickness of 5 nm to 20 nm.

The absorbing film has a reflectance of less than 10% with respect to 13.5 nm exposure light for extreme ultraviolet rays.

The absorbing film has a reflectance of less than 30% with respect to an inspection wavelength of 193 nm.

Wherein the third functional film is made of chromium or at least one light element material selected from the group consisting of oxygen (O), nitrogen (N), carbon (C), boron (B) And the composition ratio of the light source to the material is 100 at%: 0 at% to 20 at%: 80 at%.

And a buffer layer provided between the capping layer and the absorption layer.

And a conductive film provided on a rear surface of the transparent substrate.

And a polymer compound containing silicon between the resist film and a film disposed under the resist film.

The present invention can produce a photomask for extreme ultraviolet rays by using one of the above blank masks for extreme ultraviolet rays.

According to the present invention, by adjusting the composition ratio of the metal and the light source constituting the absorption film, the optical characteristics of the required absorption film can be ensured and the thinning of the absorption film can be realized. Also, according to the present invention, the thin film of the resist film can be realized by etching the absorbing film by using the functional film having different etching characteristics from the absorbing film as the etching mask. Therefore, when the pattern of 14 nm or less, especially 10 nm or less, A high quality ultraviolet ray photomask can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view illustrating a shadow effect generated in a photomask manufactured using a conventional extreme ultraviolet ray blank mask,
FIG. 2 is a view illustrating a shadow effect according to a pattern direction of a photomask fabricated using a conventional extreme ultraviolet ray blank mask,
3 is a sectional view showing a blank mask for extreme ultraviolet rays according to a first embodiment of the present invention,
4 is a cross-sectional view showing a blank mask for extreme ultraviolet rays according to a second embodiment of the present invention,
5 is a sectional view showing a blank mask for extreme ultraviolet rays according to a third embodiment of the present invention,
6 is a cross-sectional view showing a blank mask for extreme ultraviolet rays according to a fourth embodiment of the present invention,
7 is a cross-sectional view showing a blank mask for extreme ultraviolet rays according to a fifth 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.

3 is a cross-sectional view showing a blank mask for extreme ultraviolet rays according to the first embodiment of the present invention.

3, a blank mask 300 for extreme ultraviolet rays according to the present invention includes a transparent substrate 302, a multilayer reflective film 304 sequentially stacked on the transparent substrate 302, a capping film 306, (312) and a resist film (318).

The absorbing layer 312 may have a multi-layer structure in which the absorbing layer 308 and the antireflection layer 310 are laminated and may have a single layer structure when the absorbing layer 308 has an antireflection function. When the absorption layer 312 has a single-layer structure, the absorption layer 312 may be composed of a single layer having a constant composition ratio or may be formed in the form of a continuous layer in which the composition ratio varies in the thickness direction.

The transparent substrate 302 preferably has a low thermal expansion coefficient within a range of 0 占 1.0 占^10-7 / 占 폚 in order to prevent deformation of the pattern due to heat during exposure so as to be suitable as a glass substrate for a reflective mask blank using EUV light, Is an LTEM (Low Thermal Expansion Material) substrate having a low thermal expansion coefficient in the range of 0 ± 0.3 × 10 ^-7 / ° C.

The LTEM substrate is required to have a high flatness in order to increase the precision of reflected light upon exposure. TIR (Total Indicated Reading) is a value representing the warpage (deformation amount) of the surface. The plane defined by the least squares method with reference to the surface of the substrate is defined as a hyperplane, Refers to the absolute value of the difference in height between the highest position of the substrate surface and the lowest position of the substrate surface below the hyperplane. Therefore, the higher the flatness, the lower the TIR value, and the LTEM substrate preferably has a lower TIR value.

The flatness of the LTEM substrate affects the flatness of the multilayer reflective film and the capping film formed on the upper portion and further the absorption film. Particularly, when the flatness on the reflective film and the capping film is low (in the case of having a high TIR value) The exposure light is incident on the photomask at an incidence angle of about 4 ° to 6 °, and the position distribution of the pattern is generated. Therefore, it is preferable that the flatness (TIR value) of the substrate is ideally '0', but it is difficult to realize the TIR value of '0' by actual processing (for example, mechanical processing such as polishing or partial polishing) . Therefore, the flatness of the LTEM substrate has a TIR value of 60 nm or less, and preferably has a flatness of 40 nm or less.

The multilayer reflective film 304 is formed by alternately laminating 40 layers to 60 layers of molybdenum (Mo) and silicon (Si). The multilayer reflective film 304 is required to have a high reflectance for a wavelength of 13.5 nm in order to improve image contrast. The reflection intensity of the multilayer reflective film depends on the angle of incidence of the exposure light and the thickness of each layer. For example, when the angle of incidence of the exposure light is 5 °, molybdenum (Mo) and silicon (Si) Are preferably formed to have a thickness of 2.8 nm and 4.2 nm, respectively. However, when EUV liquid immersion lithography is applied, the incident angle is widened to 8 to 14 degrees, and the reflection intensity is changed. Therefore, the reflective film 304 should have a reflection intensity optimized for the final incident angle of the exposure light, wherein the molybdenum (Mo) has a thickness of 2 nm to 4 nm and the silicon has a thickness of 3 nm to 5 nm.

Since the multilayer reflective film 304 is easily oxidized when the molybdenum (Mo) is brought into contact with the atmosphere and reflectance is lowered, it is preferable to form silicon (Si) as the protective film for preventing oxidation. The reflective film 304 has a reflectance of 65% or more with respect to an exposure wavelength for extreme ultraviolet light of 13.5 nm and a reflectance of 40% to 65% with respect to an inspection wavelength of 193 nm or 257 nm. The reflective film 304 has a value of 60 nm or less in absolute value of the surface TIR, and preferably has a value of 40 nm or less. The surface roughness of the reflective film 304 has a value of 0.2 nm RMS or less and preferably 0.1 nm RMS or less.

The capping layer 306 may be formed of Ru, Ti, Mo, Ta, V, Co, Ni, Zr, Nb, Pd, Zn, Cr, Al, Mn, Cd, Mg, Li, Selenium, Cu, (H), tungsten (W), silicon (Si), or a mixture of oxygen (O), nitrogen (N), carbon (C), boron B). ≪ / RTI >

The capping layer 306 may be formed of ruthenium or niobium or may be formed of a ruthenium compound or a niobium compound and may include ruthenium and niobium . The content of the metal-to-metal light element (the sum of oxygen (O), nitrogen (N), carbon (C) and boron (B)) has a ratio of 10: 0 to 5: 5.

The capping film 306 has a thickness of 1 nm to 10 nm, and preferably has a thickness of 1 nm to 5 nm. When the thickness of the capping film 306 is 1 nm or less, it is difficult to protect the reflective film 304 formed at the bottom when etching conditions (for example, overetching, etc.) are taken into consideration when forming the upper absorber film pattern. When the thickness is 10 nm or more, the reflectance is less than 60% with respect to the exposure wavelength of 13.5 nm, so that the image sensitivity to the reflectance of the absorbing film 312 is reduced, and the inspection wavelength (for example, 193 nm or 257 nm), the inspection sensitivity to the final absorbent film is also reduced, which makes inspection difficult.

The capping film 306 has a reflectance of 60% or more with respect to an extreme ultraviolet ray exposure wavelength of 13.5 nm, has an absolute value of surface TIR of 60 nm or less, and preferably has a value of 40 nm or less. The surface roughness of the capping film 306 has a value of 0.2 nm RMS or less and preferably 0.1 nm RMS or less.

The absorption layer 312 may be formed of at least one selected from the group consisting of Ni, Tell, Sn, Pd, Se, T, Os, Ir, ), Silicon (Si), and tantalum (Ta), or one or more metal materials selected from the group consisting of oxygen (O), nitrogen (N), carbon (C), boron ) And hydrogen (H), and has an amorphous structure.

The absorption layer 312 needs to be thinned to reduce the incident angle of the light source in order to reduce the shadow effect generated during exposure of the EUV photomask. In order to reduce the thickness of the absorption layer 312, a high extinction coefficient for exposure light, an excellent etching selectivity for the etching property and the lower capping layer 306, and excellent chemical resistance Constituent materials having resistance are required. The currently used tantalum (Ta) has an extinction coefficient of 0.0408 with respect to an exposure wavelength of 13.5 nm, and a thickness of 70 nm or more is required to satisfy a constant reflectance in an absorbing film containing tantalum (Ta) as a main component.

The present invention forms an absorbing film 312 with a nickel (Ni) or nickel (Ni) compound, and nickel (Ni) has an extinction coefficient of 0.0727 for an exposure wavelength of 13.5 nm, Nm or less in thickness. In addition, nickel nitride (NiN) among the nickel (Ni) compounds is excellent in dry etching characteristics, and an amorphous thin film is realized with respect to the etching characteristic of the absorbing film 312 including nickel So that the characteristics of the pattern can be made excellent.

When the absorption layer 312 is formed of nickel (Ni) or nickel tantalum (NiTa) compound, oxygen (O), nitrogen (N), carbon (C), boron (H), and the like. At this time, the absorption layer 312 may be formed of one or more of light elements (oxygen (O), nitrogen (N), carbon (C), boron (B), hydrogen (H) ) Has a composition ratio of 95 at%: 5 at% to 20 at%: 80 at%. When the absorption layer 312 is formed to include nickel tantalum (NiTa), the nickel tantalum (NiTa) target has a composition ratio of Ni: Ta = 5 at% to 95 at%: 95 at% to 5 at%.

The absorption film 312 requires a low reflectance of 25% or less at the inspection wavelength (193 nm or 257 nm) in order to have a reflectance difference contrast with the multilayer reflective film 304. For example, when the absorption layer 312 has a multilayer structure of the absorption layer 308 and the antireflection layer 310, the antireflection layer 310 may include oxygen (O), nitrogen (N), it is possible to lower the reflectance at the inspection wavelength. In addition, the absorption layer 308 has a lower oxygen (O) content than the antireflection layer 310 in order to increase the light absorptivity and reduce the thickness. The absorption layer 308 is made of one of nickel nitride (NiN) or nickel tin nitride (NiTaN) and the antireflection layer 310 is made of either nickel oxynitride (NiON) or nickel tin oxide (NiTaON). (NiN), nickel tin nitride (NiTaN), nickel oxynitride (NiON), and nickel oxynitride tantalum (NiTaON) constituting the absorption film 312 of the present invention are all etchable with chlorine , The absorption layer 312 can be etched by a single etching process, which simplifies the process and reduces the probability of occurrence of defects and foreign matter.

In the case where the absorption layer 312 has a single layer structure, the absorption layer 312 mainly composed of nickel (Ni) or nickel tantalum (NiTa) has a higher content of oxygen (O) and nitrogen (N) And the content of oxygen (O) decreases from the bottom to the bottom, so that the reflectance at the inspection wavelength can be lowered and the light absorption rate can be increased.

The absorbing film 312 has a thickness of 30 nm to 70 nm. When the thickness of the absorbing film 312 is 30 nm or less, the reflectance with respect to the exposure light is 10% or more, and the reflectance is high. When the thickness is 70 nm or more, the threshold value deviation of the transverse- Which leads to the uniformity of the threshold number and the increase of MEEF (Mask-Enhanced Error Factor).

The absorbing film 312 has a reflectance of less than 10%, preferably 5% or less, and more preferably 1% or less, with respect to the exposure light for extreme ultraviolet light of 13.5 nm. Further, the absorption film 312 has a reflectance of less than 30% with respect to the inspection wavelength of 193 nm, and preferably has a reflectance of 25% or less. The thin film stress of the absorbing film 312 is 200 MPa or less and preferably has a thin film stress of 150 MPa or less.

A chemically amplified resist (CAR: Chemically Amplified Resist) is used as the resist film 318. The resist film 318 has a thickness of 150 nm or less, preferably 100 nm or less, more preferably 60 nm or less Thickness.

For example, on the antireflection layer 310 of the absorptive film 312, silicon coated to improve the adhesion to the resist film may be formed on the film disposed below the resist film 318 May be formed. The silicon-containing polymer may be selected from the group consisting of hexamethyldisilane, trimethylsilyldiethyl-amine, O-trimethylsilylacetate, O-trimethylsilyl- proprionate, O-trimethylsilylbutyrate, trimethylsilyl-trifluoroacetate, trimethylmethoxysilane, N-methyl-N-trimethylsilyltrifluoroacetamide N- methyl-Ntrimethylsilyltrifluoroacetate, O-trimethylsilylacetylacetone, isopropenoxy-trimethylsilane, trimethylsilyl-trifluoroacetamide, methyltrimethylsilyldimethylketone acetate, -Silyldimethylketoneacetate), trimethyl-ethoxy silane).

4 is a cross-sectional view showing a blank mask for extreme ultraviolet rays according to a second embodiment of the present invention.

4, the blank mask for extreme ultraviolet rays according to the present invention includes a transparent substrate 302, a multilayer reflective film 304 sequentially stacked on the transparent substrate 302, a capping film 306, an absorbing film 312, A first functional film 314, and a resist film 318, as shown in FIG. Here, the multilayer reflective film 304, the capping film 306, and the absorbing film 312 including nickel (Ni) or nickel tantalum (NiTa) are configured in the same manner as in the first embodiment described above.

The first functional film 314 is composed of a material having an etching property different from that of the absorption layer 312 to serve as an etching mask for patterning the absorption layer 412 disposed below. The functional film 314 has an etch selectivity ratio of at least 1:10, and preferably an etch selectivity of at least 1:20, as compared to the absorbing film 312. That is, the first functional film 314 may be formed by forming the first functional film 314 such that the absorption film 312 is composed of nickel nitride (NiN), nickel tantalum nitride (NiTaN), nickel oxide nitride (NiON), or nickel oxide tantalum (NiTaON) The first functional film 314 may be formed of a material which can be etched by a fluorine (F) -based gas. For this, the first functional film 314 may be formed of one selected from the group consisting of Cr, tantalum, silicon, ruthenium, titanium, molybdenum, tungsten, (N), carbon (C), boron (B), and hydrogen (H) to at least one material selected from the group consisting of silicon At least one of the materials. At this time, the functional film 314 has a composition ratio of 100 atomic% to 0 atomic% to 20 atomic%: 80 atomic% of the metal-to-metal atom ratio.

When the first functional film 314 is formed as a single layer or a multilayer structure of two or more layers and has a single layer, the first functional film 314 may have a continuous film or a single film having a constant composition ratio of the film continuously changing the composition ratio of the film during sputtering, Structure.

The first functional film 314 must be thin and etched at a high speed in order to thin the resist film 318. For this purpose, the functional film 314 has a thickness of 1 nm to 10 nm, preferably 3 nm To 5 nm.

The first functional film 314 is removed during the manufacturing process of the photomask, and in some cases, an enhancement of the antireflection layer role may remain if necessary.

5 is a cross-sectional view showing a blank mask for extreme ultraviolet rays according to a third embodiment of the present invention.

5, a blank mask 400 for extreme ultraviolet rays according to the present invention includes a transparent substrate 402, a multilayer reflective film 404 sequentially stacked on the transparent substrate 402, a capping film 406, 408 and a second functional film 416 and a resist film 418. The second functional film 416 is formed of a resist film 418, Here, the multilayer reflective film 404, the capping film 406, and the absorbing layer 408 are configured in the same manner as in the first embodiment described above.

The second functional film 416 is used as an etching mask of the absorption layer 408 and remains on the pattern of the absorption layer 408 after patterning of the absorption layer 408 to serve as an antireflection layer. Accordingly, the absorbing layer 408 has a low oxygen (O) content mainly for increasing the light absorptivity and thinning, and thus consists of one of nickel nitride (NiN) or nickel tin nitride (NiTaN).

The absorption layer 408 has a thickness of 20 nm to 50 nm and has an absolute value of surface TIR of 60 nm or less and preferably 40 nm or less. The surface roughness of the absorbing layer 408 has a value of 0.2 nm RMS or less and preferably 0.1 nm RMS or less.

The second functional film 416 has an etch selectivity to the absorber layer 408 of at least 1:10 to serve as an etch mask. That is, since the second functional film 416 can be etched with chlorine (Cl) based gas composed of nickel nitride (NiN) or nickel tantalum (NiTaN), the absorption layer 408 can be etched with a fluorine Material. For this, the second functional film 416 may be formed of at least one selected from the group consisting of Cr, tantalum, silicon, ruthenium, titanium, molybdenum, tungsten, (N), carbon (C), boron (B), and hydrogen (H) to at least one material selected from the group consisting of silicon At least one of the materials. In this case, the second functional film 314 has a composition ratio of 100 atomic% to 0at% to 20 atomic%: 80 atomic% of the metal to silicon atom ratio.

The second functional film 416 is required to have a high etch rate and a small thickness for the purpose of thinning the resist film 418, but a thickness of more than a certain thickness is required for the antireflection function. To this end, the second functional film 416 has a thickness of 5 nm to 20 nm, preferably 10 nm to 15 nm.

The absorption film 412 in which the absorption layer 408 and the second functional film 416 are laminated has a reflectance of less than 10% with respect to 13.5 nm exposure light for extreme ultraviolet light, preferably a reflectance of 5% or less, , And has a reflectance of 1% or less. Further, the absorption film 412 has a reflectance of less than 30% with respect to the inspection wavelength of 193 nm, and preferably has a reflectance of 25% or less.

A chemically amplified resist is used as the resist film 418. The thickness of the resist film 418 is 150 nm or less considering the thickness of the functional film, preferably 100 nm or less, more preferably 80 nm or less .

6 is a cross-sectional view showing a blank mask for extreme ultraviolet rays according to a fourth embodiment of the present invention.

6, a blank mask 400 for extreme ultraviolet rays according to the present invention includes a transparent substrate 402, a multilayer reflective film 404 sequentially laminated on the transparent substrate 402, a capping film 406, The third functional film 420, and the resist film 418, which are formed of the first functional film 408 and the second functional film 416, respectively. Here, the multilayer reflective film 404, the capping film 406, and the absorbing layer 408 are the same as those in the above-described first embodiment, and the second functional film 416 is the same as in the above- And an antireflection layer.

The third functional film 420 serves as an etch mask for the second functional film 416. To this end, the third functional film 420 has an etch selectivity of at least 1:10 for the second functional film 416 . That is, the third functional film 420 preferably includes a fluorine (F) -based gas, which is an etching gas of the second functional film 416, that is excellent in etching resistance and can be etched by a chlorine (Cl) -based gas. Therefore, the third functional film 420 may be formed of chromium (Cr) containing a light element such as oxygen (O), nitrogen (N), carbon (C), boron (B) Compounds.

When the third functional film 420 is formed as a single layer or a multilayer structure of two or more layers and is formed as a single layer, the third functional film 420 may have a continuous film or a single film having a constant composition ratio of the film continuously changing the composition ratio of the film during sputtering, Structure.

The third functional film 420 has a thickness of 1 nm to 10 nm and preferably has a thickness of 3 nm to 10 nm. And has a thickness of 5 nm.

The third functional film 420 may be removed during the manufacturing process of the photomask, and in some cases, if an enhancement of the antireflection role of the second functional film 416 is required, it may remain.

A chemically amplified resist (CAR: Chemically Amplified Resist) is used as the resist film 418. The resist film 418 has a thickness of 150 nm or less, preferably 100 nm or less, more preferably 60 nm or less Thickness.

7 is a cross-sectional view showing a blank mask for extreme ultraviolet rays according to a fifth embodiment of the present invention.

Referring to FIG. 7, the blank mask 300 for EUV radiation according to the present invention may further include a buffer film 307 provided between the capping film 306 and the absorption film 308. The buffer film 307 serves to prevent the multilayer reflective film 304 from being damaged in the dry etching process for forming the absorption film 308 pattern. In addition, it protects the multilayer reflective film 304 in a repair process performed when a black defect or a white defect occurs in an absorbent film pattern in the process of manufacturing a photomask for extreme ultraviolet rays.

The buffer film 307 is made of a material having an etch selectivity with the absorption film 308 and is made of, for example, a chromium (Cr) compound, and the buffer film 307 is formed using a focused ion beam (EB correction) using a fluorine-based gas (Xe ₂ F or the like) with an electron beam and a non-excited state when the focused ion beam is not used Is used), it is preferable to have a thickness of 5 nm to 15 nm.

The function of the buffer film 307 can be added to the capping film 306 when the buffer film 307 is not formed in the extreme ultraviolet ray mask 300 of the present invention.

8 is a cross-sectional view showing a blank mask for extreme ultraviolet rays according to a sixth embodiment of the present invention.

Referring to FIG. 8, the EUV blank mask 300 according to the present invention may further include a conductive film 309 provided on the rear surface of the transparent plate 302. The conductive film 309 can be selectively formed on the back surface of the LTEM substrate and may be formed on the back surface of the substrate after the multilayer reflective film 304, the capping film 306, and the absorption film 308 are formed on the LTEM substrate, The conductive film can be preferentially formed on the rear surface of the substrate before forming the multilayer reflective film 304, the capping film 306, and the absorbing film 308 on the LTEM substrate. The conductive film 309 serves to assist the bonding between the blank mask for extreme ultraviolet rays and the electro-chuck, and has a low surface resistance for improving the adhesion with the electrostatic chuck. The conductive film 309 improves the adhesion between the electrostatic chuck and the extreme ultraviolet ray blank mask and serves to prevent particles from being generated by the conductive film due to friction between the electrostatic chuck and the conductive film. Therefore, the conductive film has a surface resistance value of 100? /? Or less, and preferably has a resistance value of 50? /? Or less, more preferably 20? /? Or less.

The conductive film 309 is formed of a material selected from the group consisting of titanium (Ti), 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), carbon (C), and boron (B) in the metal material, or one or more metal elements selected from the group consisting of oxygen (O), nitrogen Or more.

The conductive film 309 has a thickness of 70 nm or less and can be formed as a single film of single layer, a continuous film of a single layer, or a multilayer film. The conductive film 309 has a reflectance of 30% or less at a wavelength of 193 nm to 257 nm. For example, the conductive film 309 may be formed of chromium (Cr) as a main component. When the conductive film 309 is formed of a multilayer film of two layers, the lower layer may include chromium (Cr) and nitrogen (N) And the upper layer may include chromium (Cr), nitrogen (N), and oxygen (O). At this time, the conductive film 309 has a composition ratio of chromium (Cr) and light element (sum of oxygen (O), nitrogen (N), carbon (C), and boron (B)) of 8: 2 to 2: .

In addition, although not shown, the extreme ultraviolet blank mask according to the present invention may include or include a buffer film, a conductive film, and a polymer including silicon.

In addition, the multilayer reflective film, the capping film, the absorbing film, the functional film, the buffer film and the conductive films can be selectively heat-treated, and the heat treatment process can be performed using a rapid thermal process (RTP), a vacuum hot- Plate Bake, Plasma, and Furnace.

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

(Example)

nickel( Ni ) Absorbent film  Formed For ultraviolet rays  Blank mask evaluation

For the manufacture of a pole UV blank mask, the substrate 6 inch x 6 inch x 0.25 inch with the size of the flatness (TIR value) is controlled to less than 60㎚, SiO ₂ -TiO component consisting LTEM (Low Thermal Expansion Material substrate was prepared.

On the rear surface of the LTEM substrate, a conductive layer made of chromium (Cr) as a main component was formed using a DC magnetron reactive sputtering facility. The conductive film was formed into a two-layer structure of chromium nitride (CrN; lower layer) and chromium oxynitride (CrON (upper layer)). The upper and the lower layer conductive film in both the chromium (Cr) formed with the target and the conductive film of the lower layer process gas Ar: N ₂ = 5sccm: using 5sccm injection, and power 1.4㎾ process has a thickness of 42㎚ And a chromium nitride (CrN) film. The upper conductive film was formed by implanting Ar: N ₂ : NO = 7 sccm: 7 sccm: 7 sccm as a process gas and a process power of 1.4 kW to form a chromium oxynitride (CrON) film having a thickness of 24 nm. Finally, the conductive film was formed to a thickness of 66 nm, and the sheet resistance of the formed conductive film was measured using a 4-point probe, and it showed a sheet resistance value of 16.5? / ?. Thus, there was no problem in E-chucking with the electrostatic chuck Respectively.

Molybdenum (Mo) of 4.8 nm, silicon (Si) of 2.2 .mu.m was deposited on the front surface of the LTEM substrate using an ion beam deposition-low defect density (hereinafter referred to as IBD-LDD) 40 layers were alternately formed to form a multilayer reflective film. The reflectance of the multilayer reflective film was measured using an EUV reflectometer. As a result, the reflectance was 67.8% at a wavelength of 13.5 nm and 64.66% at a wavelength of 193 nm. The surface roughness of the multilayer reflective film was measured using an AFM (Atomic Force Microscopy) apparatus. The surface roughness of the multilayer reflective film was measured to be 0.12 nmRMS. As a result, the EUV exposure light was reflected by the surface roughness Of the total number of patients. In addition, the flatness of the 142 mm 2 area of the multilayer reflective film was measured using the Ultra-Flat equipment, and it was found that the TIR (Total Indicated Reading) value of 54 nm was obtained and the pattern position distortion caused by the reflective film was small.

On the multilayer reflective film, ruthenium (Ru) was deposited to a thickness of 2.5 nm using IBD-LDD equipment to form a capping film. After the formation of the capping film, the reflectance was measured in the same manner as in the case of the multilayer reflective film. As a result, it was confirmed that the reflectance was 65.8% at a wavelength of 13.5 nm and that the reflectance was almost unchanged compared with 67.8% which was the reflectance value of the multilayer reflective film. As a result of measuring the reflectance at a wavelength of 193 nm, the reflectance was 55.43%. The surface roughness and flatness were measured in the same manner. As a result, the surface roughness value was 0.13 nmRMS, which showed almost no change compared to the multilayered reflective film, and the TIR value was also found to be 54 nm.

A Ni (Ni) absorption layer having a two-layer structure composed of an absorption layer and an antireflection layer was formed on the capping layer using a DC magnetron reactive sputtering equipment. Absorption of a two-layer film was used both for the nickel (Ni) target, the lower absorbent layer in the process gas Ar: N ₂ = 8sccm: 2sccm injection and process power of 30㎚ thickness nitridation using 1.0㎾ nickel (NiN) Layer. At this time, the reflectance of the lower absorber layer was 1.6% at an exposure wavelength of 13.5 nm.

The upper antireflective layer was injected with Ar: N ₂ : NO = 5 sccm: 5 sccm: 3 sccm as the process gas, and a process power of 1.0 kW was used to form a 12 nm thick nickel oxyhydroxide (NiON) layer. As in the case of the absorbing layer, the reflectance was measured at an exposure wavelength of 13.5 nm. As a result, the reflectance was 0.9% and the reflectance was 22.3% at a wavelength of 193 nm.

The flatness of the Ni-containing absorbent layer was measured using an Ultra-Flat instrument, and the TIR value of 70 nm was obtained. The variation of the TIR value was slightly higher than 16 nm when compared with the TIR value at the time of forming the capping layer. However, when the thin film stress was converted into the thin film stress, it was confirmed that the thin film stress had a value of about 150 MPa.

As a result of analyzing the composition ratio according to the depth of the absorbent film using the AES equipment, the upper antireflection layer showed a ratio of nickel (Ni): light element (O, N) of 4: 6, Ni): light element (N) showed a ratio of 8: 2.

nickel( Ni ) And tantalum Ta ) Absorbent film  Formed For ultraviolet rays  Blank mask evaluation

The blank mask for extreme ultraviolet rays on which an absorbing film containing nickel (Ni) as the main component was formed was evaluated in the same manner as in the evaluation of the blank mask for extreme ultraviolet rays, in which an absorbing film composed mainly of nickel (Ni) and tantalum (Ta) was formed. Here, the lower films except for the absorbing film are the same as those for the extreme ultraviolet ray on which the above-described absorbing film composed mainly of nickel (Ni) is formed.

The absorbing film was formed into a two-layer structure including nickel tantalum (NiTa) using a DC magnetron reactive sputtering facility. (Ni: Ta = 90 at%: 10 at%, 70 at%: 30 at%, 50 at%: 50 at%, and 10 at%: 90 at%) of a nickel tantalum (NiTa) target. At this time, the lower absorption layer was injected with Ar: N ₂ = 8 sccm: ₂ sccm as the process gas, and the process power was 1.0 kW to form a 31 nm thick nickel tantalum nitride (NiTaN) layer. The upper antireflective layer was injected with Ar: N ₂ : NO = 5 sccm: 5 sccm: 3 sccm as a process gas, and a process power of 1.0 kW was used to form a 14 nm thick layer of nickel tantalum nitride (NiTaON).

The reflectance of each absorbing film was measured using an EUV Reflecto-meter. As a result, the absorbing films exhibited a reflectance of 0.9% to 1.0% at an exposure wavelength of 13.5 nm and a reflectance of 19.5% to 21.2% at an inspection wavelength of 193 nm Reflectance.

tantalum( Ta ) As a main component Absorbent film  Formed For ultraviolet rays  Blank mask comparison

As a comparative example, a blank mask for extreme ultraviolet rays on which an absorbing film composed mainly of tantalum (Ta) was formed was manufactured and characteristics were compared with a blank mask having an absorbing film composed of nickel (Ni) or nickel tantalum (NiTa) Here, the lower films except for the absorbing film are the same as those for the extreme ultraviolet ray on which the above-described absorbing film composed mainly of nickel (Ni) is formed.

The absorbing film was formed into a two-layer structure including tantalum (Ta) using a DC magnetron reactive sputtering equipment. The tantalum (Ta) target was used for all of the two absorbing layers, and the lower absorbing layer was formed by injecting Ar: N ₂ = 8 sccm: ₂ sccm as the process gas and a process power of 1.0 kW as the tantalum nitride (TaN) layer , And the thickness was measured at a portion where the reflectance was 1.5% at an exposure wavelength of 13.5 nm. As a result, the absorption layer showed a thickness of 55 nm. The upper antireflective layer was formed by implanting Ar: N ₂ : NO = 5 sccm: 5 sccm: 3 sccm as a process gas, a process power of 1.0 kW as a tantalum oxynitride (TaON) layer, and a reflectance at an exposure wavelength of 13.5 nm 1.0%, and the entire absorbent film had a thickness of 70 nm, which was larger than that of the present invention.

Table 1 below shows the composition ratios, thicknesses, and reflectivities of the films according to the composition of the hard earth relative to the metals of the absorbent films containing nickel (Ni) and nickel tantalum (NiTa) and tantalum (Ta).

Target
(Composition ratio)
Composition ratio of membrane
(Metal: light element) Absorption membrane
thickness
(nm) reflectivity
(%) Absorbing layer Antireflection layer @ 13.5 nm @ 193 nm Example 1 Ni 8: 2 4: 6 42 0.9 22.3 Example 2 NiTa
(9: 1) 6: 2: 2 5: 1: 4 45 1.0 21.2 Example 3 NiTa
(7: 3) 5: 3: 2 4: 1.5: 4.5 54 0.9 20.9 Example 4 NiTa
(5: 5) 4.3: 3.5: 2.2 3.5: 2: 4.5 60 1.0 19.5 Example 5 NiTa
(1: 9) 1.5: 7: 1.5 0.9: 5.1: 4 65 1.0 20.2 Comparative Example Ta 8: 2 3: 7 70 1.0 20.2

Referring to Table 1, when an absorbing film is formed using nickel (Ni) or nickel tantalum (NiTa) as in Examples 1 to 5, compared with the comparative example in which an absorbing film is formed using tantalum (Ta) , 13.5 nm, and 193 nm as the inspection wavelength, the thickness of the absorbing film for satisfying the same reflectance is thin.

The first functional film  Equipped For ultraviolet rays  Preparation and Evaluation of Blank Mask

After forming a conductive film, a multilayer reflective film, a capping film, and an absorbing film mainly composed of nickel (Ni) on the LTEM substrate in the same manner as the above-described EUV mask, a DC magnetron reactive sputtering equipment Thereby forming a first functional film. The first functional film is a boron (B) is added (Doping) A silicon (Si) targets using the (composition ratio Si: 20 B = 98:: 2 ~ 80), the process gas by _{Ar: N 2: NO = 5sccm} : 3 sccm: 2 sccm and a process power of 0.6 kW was used to form a silicon oxynitride boron (SiBON) film having a thickness of 4 nm.

At this time, the first functional film exhibited a reflectance of 0.85% at an exposure wavelength of 13.5 nm, and the flatness was measured using an Ultra-Flat equipment. As a result, a TIR value of 77 nm was obtained. The results showed that Si: B: O: N = 72at%: 3at%: 10at%: 15at%.

Hexamethyldisilane was applied to the first functional film to improve adhesion to the resist film. Then, a chemically amplified resist film was formed to a thickness of 80 nm, Blank mask fabrication was completed.

The first functional film  Used For ultraviolet rays Photomask  Manufacturing and Evaluation

An extreme ultraviolet ray photomask was manufactured and evaluated by using a blank mask for extreme ultraviolet ray using the first functional film as an etching mask.

The extreme ultraviolet blank mask was exposed using a 50 keV writing apparatus, and a pattern was formed on the resist film through PEB (post exposure bake) and development (Develope). Then, the functional film composed of silicon nitride boron (SiBON) was etched using the resist film pattern for 30 seconds (over etching considered) using an etching gas containing SF ₆ gas as a fluorine (F) Respectively. At this time, the thickness of the remaining resist film was measured. As a result, the remaining resist film thickness was found to be 30 nm, confirming that the resist film had a sufficient role as an etching mask.

Thereafter, the residual resist film was removed, and the first functional film having the pattern formed thereon was etched using an etch gas containing chlorine (Cl) using an etch mask. As a result of measuring the thickness of the first functional film after etching, it was found that the etching selectivity ratio was 1: 50 (functional film: absorbing film) and the etch selectivity ratio was 20 or more.

Then, the first functional film was removed to complete the manufacture of a photomask for extreme ultraviolet rays.

As a result of measuring the resolution of the extreme ultraviolet photomask according to the present invention using a CD-SEM, the resolution of the single space pattern (Iso-space) was defined up to 40 nm and the linearity of the critical number (Iso-line), 3.0 nm in line and space patterns (Line & Space), and 3.2 nm in a single space pattern (Iso space) as a result of measurement in a range of 60 nm to 1000 nm And showed excellent results.

Functional membrane  Unmet For ultraviolet rays  Blank masks and their use For ultraviolet rays Photomask  Manufacturing and Evaluation

As a comparative example, an extreme ultraviolet ray blank mask on which an absorber film containing tantalum (Ta) as a main component was formed was fabricated, and an absorptive film composed mainly of nickel (Ni) or nickel tantalum (NiTa) The properties of the blank mask for extreme ultraviolet light with a functional film were compared.

As in the above-described comparative example, in the case of the extreme ultraviolet ray blank mask in which the absorber film containing tantalum (Ta) as a main component was formed, the absorber film was nitrided to a thickness of 55 nm to satisfy exposure and inspection conditions for exposure wavelengths of 13.5 nm and 193 nm An absorber layer was formed of a tantalum (TaN) layer, and an antireflective layer was formed of a 15 nm thick tantalum oxynitride (TaON) layer to have a total thickness of 70 nm.

Thereafter, a chemically amplified resist film was coated to a thickness of 80 nm, exposed to light using an e-beam writing device, and subjected to PEB and development to form a resist film pattern. Since the lower portion of the absorbent layer consisting of the resist film pattern as an etching mask, oxide tantalum nitride (TaON) of the antireflection layer etched using the SF ₆ gas, and tantalum nitride (TaN) consisting of a top of the absorbing film with a the Cl ₂ gas Respectively. Thereafter, the thickness of the remaining resist film was measured. As a result, there remained no resist film, and it was confirmed that a part of the upper part of the absorbing film pattern was etched and damaged. As a result, the chemically amplified resist film was coated at 120 nm, and the absorbing film was etched under the same conditions. As a result, the remaining resist film was formed to be 20 nm so as not to damage the absorbing film pattern.

Subsequently, the resolution of the photomask for extreme ultraviolet rays was measured using a CD-SEM. As a result, it was developed to 60 nm in the case of a single space pattern (Iso space), and the CD linearity of the critical number was measured at 60 nm to 1000 nm As a result of the measurement, a value of 4.5 nm in a single line pattern (Iso-line), 7.5 nm in a line and space pattern (Line & Space), and 5.2 nm in a single space pattern (Iso-space) Which is not good compared with the photomask.

Depending on the constituent material The first functional film  Physical and chemical characterization

In the production of the blank mask for EUV according to the present invention, the physical and chemical properties of the material constituting the first functional film were evaluated.

And the first functional film composed of the above-described silicon nitride boron (SiBON), and the first functional film was formed as a process gas in which Ar: N ₂ : NO = 6 sccm to 10 sccm : 4 sccm to 6 sccm: 0 to 4 sccm, and each functional film was formed using a process power of 0.6 to 1.0 kW.

Table 2 is a table comparing thickness and etching selectivity according to the constituent materials and composition of the first functional film.

Constituent material Target
(Composition ratio) thickness Etching selection ratio
(Absorbing film: hard film) Composition ratio
(Metal: light element) Etching gas Example 6 SiBN SiB 4 nm 45: 1 Si: B: N = 72: 3: 25 SF ₆ Example 7 MoSiN MoSi
[5:95] 3 nm 43: 1 Mo: Si: N = 4: 76: 20 SF ₆ Example 8 MoSiN MoSi
[10:90] 3 nm 40: 1   Mo: Si: N = 7: 72: 21 SF ₆ Example 9 TaON Ta 4 nm 30: 1   Ta: O: N = 72: 16: 12 SF ₆

Referring to Table 2, it can be seen that all of the embodiments have an etch selectivity ratio of 20 or more as compared to the absorbing film and have a thickness of 3 nm to 4 nm, thereby satisfactorily serving as an etch mask. In addition, the flatness of each functional film was measured using Ultra-Flat equipment. As a result, it was confirmed that the TIR value of 75nm ~ 80nm was not affected by the thin film stress.

Etching  Mask and With antireflection layer  Acting The second functional film  Equipped For ultraviolet rays  Preparation and Evaluation of Blank Mask

In the production of a blank mask for extreme ultraviolet rays according to the present invention, a blank mask for extreme ultraviolet rays, which is provided with a second functional film serving as an etching mask and an antireflection layer, was produced and evaluated.

And a first functional film composed of the above-described silicon oxynitride boron (SiBON) in preparation of a transparent substrate, a multilayer reflective film and a capping film, and was constructed in the same manner as in the manufacture and evaluation of an extreme ultraviolet blank mask. The absorbent layer was formed.

The absorber was a DC magnetron reactive sputtering system and a nickel (Ni) target was used. Ar: N ₂ = 8 sccm: ₂ sccm was injected as the process gas and the process power was 1.0 kW. NiN) layer.

A second functional film was then formed on the absorber using a DC magnetron reactive sputtering facility. The second functional film was injected with Ar: N ₂ : NO = 6 sccm to 10 sccm: 4 sccm to 6 sccm: 0 to 4 sccm as the process gas, and the functional film was formed using the process power of 0.6 kW to 1.0 kW.

Table 3 is a table for evaluating the reflectance at each wavelength according to the constituent materials, composition ratio, and thickness of the second functional film.

Configuration
matter Target
(Composition ratio) thickness reflectivity
@ 13.5 nm reflectivity
@ 193 nm Composition ratio
(Metal: light element) Etching
gas Example 10 SiBON SiB 14rnm 1.2% 18.5% Si: O: N: B
= 42: 32: 16: 2 SF ₆ Example 11 MoSiN MoSi
[5:95] 15 nm 1.0% 18.9% Mo: Si: N
= 4: 60: 36 SF ₆ Example 12 MoSiN MoSi
[10:90] 14 nm 1.1% 19.5% Mo: Si: N
= 8: 58: 34 SF ₆ Example 13 TaON Ta 15 nm 1.0% 21.0% Ta: O: N
= 52:24:24 SF ₆

Referring to Table 3, the second functional film exhibited a reflectance of 1.0% to 1.2% and 18.5% to 21.0% at the exposure wavelength (13.5 nm) and the inspection wavelength (193 nm) And the optical properties were similar.

Thus, the etch selectivity with the absorber film can be maintained while maintaining the optical properties, which is excellent.

The third functional film Etching  Used as a mask For ultraviolet rays  Preparation and Evaluation of Blank Mask

In manufacturing the extreme ultraviolet blank mask according to the present invention, a second functional film serving as an etching mask and an antireflection layer for patterning the absorber layer, and a third functional film used as an etching mask for patterning the second functional film And a blank mask for extreme ultra-violet ray was produced and evaluated.

The third functional film was formed using a DC magnetron reactive sputtering equipment, and a chromium (Cr) target was used. Ar = 8 sccm was injected into the process gas as the process gas, and the second functional film was formed in the same manner as in the above- The process power was formed to a thickness of 4 nm using 0.7 kW. Thereafter, a surface treatment was performed at 350 ° C for 20 minutes using a rapid vacuum heat treatment (Vacuum RTP) equipment, and a chemically amplified resist film was formed to a thickness of 80 nm.

Subsequently, the prepared extreme ultraviolet blank mask was exposed using a 50 keV writing apparatus, and a pattern was formed on the resist film through PEB (post exposure bake) and development (Develope). Then, using the resist film pattern, the third functional film composed of chromium (Cr) was etched for 150 seconds (over etching time) using an etching gas containing chlorine (Cl). At this time, the thickness of the remaining resist film was measured. As a result, the remaining resist film thickness was found to be 23 nm, confirming that the resist film had a sufficient role as an etching mask. Then, the removal of the residual resist film pattern is formed and the film forming capabilities The third functional film is an etching mask (mask Etch) in the functional film forming a second functional film is fluorine (F) series gas SF ₆ And etched using an etching gas containing a gas. Further, the absorber layer composed of nickel nitride (NiN) was etched using an etching gas containing chlorine (Cl), and the third functional film composed of chromium (Cr) was also removed to form a final absorber film pattern.

As a result of measuring the resolution of the photomask for extreme ultraviolet ray according to the present invention using a CD-SEM, the result was defined to 40 nm in the case of a single space pattern (Iso-space), and the linearity of the critical number (Iso-line), 2.5 nm in line and space pattern (Line & Space), and 2.8 nm in a single space pattern (Iso space) as a result of measurement in a range of 60 nm to 1000 nm And showed excellent results.

While the present invention has been described with reference to the preferred embodiments thereof, the technical scope of the present invention is not limited to the range described in the above embodiments. It will be readily apparent to those skilled in the art that various changes and modifications can be made to the embodiments described above. It is apparent from the description of the claims that the form of such modification or improvement can be included in the technical scope of the present invention.

102: transparent substrate 104: reflective film
106: absorbing film 106a: absorbing film pattern
300, 400: Blank mask for ultraviolet rays
302, 402: transparent substrate 304, 404: reflective film
306, 406: capping film 307: buffer film
308, 408: Absorbing layer 310: Antireflection layer
312, 412: absorbing film 314, 414, 416: functional film
317: conductive films 318 and 418: resist film

Claims (20)

A blank mask for extreme ultraviolet light, comprising a transparent substrate, a multilayer reflective film, a capping film, an absorbing film and a resist film sequentially laminated,
Wherein the absorbent film comprises at least one of nickel (Ni) and nickel tantalum (NiTa). An extreme ultraviolet blank mask in which a reflective film, a capping film, an absorbing film, a first functional film, and a resist film are sequentially laminated on a transparent substrate,
Wherein the absorption layer comprises at least one of nickel (Ni) and nickel tantalum (NiTa)
Wherein the first functional film functions as an etch mask for patterning the absorber film. An extreme ultraviolet blank mask in which a reflective film, a capping film, an absorbing film composed of an absorbing layer and a second functional film, and a resist film are sequentially laminated on a transparent substrate,
Wherein the absorbing layer comprises at least one of nickel (Ni) and nickel tantalum (NiTa)
The second functional film functions as an etching mask for patterning the absorber layer and as an antireflection layer remaining on the top of the absorber layer. An extreme ultraviolet blank mask in which a reflective film, a capping film, an absorptive layer, an absorptive film composed of a second functional film, a third functional film and a resist film are sequentially laminated on a transparent substrate,
Wherein the absorbing layer comprises at least one of nickel (Ni) and nickel tantalum (NiTa)
The second functional film functions as an etching mask for patterning the absorber layer and an antireflection layer remaining on the absorber layer,
And the third functional film functions as an etching mask for patterning the second functional film. 5. The method according to any one of claims 1 to 4,
Wherein the absorption layer further comprises at least one light element material selected from the group consisting of oxygen (O), nitrogen (N), carbon (C) and boron (B) Is 99at%: 1at% to 20at%: 80at%. The method according to claim 3 or 4,
Wherein the absorption layer further comprises at least one light element material selected from the group consisting of oxygen (O), nitrogen (N), carbon (C) and boron (B) Is 99at%: 1at% to 20at%: 80at%. The method according to claim 3 or 4,
Wherein the composition ratio of the nickel tantalum (NiTa) target has a composition ratio of Ni: Ta = 5 at% to 95 at%: 95 at% to 5 at% when the absorption layer is formed to include nickel tantalum (NiTa) Mask. The method of claim 3,
Wherein the thickness of the laminated layer of the absorbing film and the second functional film is in the range of 30 nm to 70 nm. The method according to claim 2, wherein
The first functional film may be formed of at least one material selected from the group consisting of Cr (Cr), Ta (Ta), Molybdenum (Mo), and Si (Si) Wherein the composition ratio of the light source to the material is 100 at%: 0 at% to 20 at%: 80 at%, and at least one light source material selected from the group consisting of boron (C), boron (B) Blank mask for extreme ultraviolet rays. 4. The method according to claim 3 or 4, wherein
Wherein the second functional film is made of at least one material selected from the group consisting of Cr (Cr), Ta (Ta), Molybdenum (Mo), and Si (Si) Wherein the composition ratio of the light source to the material is 100 at%: 0 at% to 20 at%: 80 at%, and at least one light source material selected from the group consisting of boron (C), boron (B) Blank mask for extreme ultraviolet rays. 3. The method of claim 2,
Wherein the first functional film has a thickness of 1 nm to 10 nm. 5. The method of claim 4,
Wherein the third functional film has a thickness of 1 nm to 10 nm. The method according to claim 3 or 4,
Wherein the second functional film has a thickness of 5 nm to 20 nm. 5. The method according to any one of claims 1 to 4,
Wherein the absorbing film has a reflectance of less than 10% with respect to 13.5 nm exposure light for extreme ultraviolet rays. 5. The method according to any one of claims 1 to 4,
Wherein the absorbing film has a reflectance of less than 30% with respect to an inspection wavelength of 193 nm. 5. The method of claim 4,
Wherein the third functional film is made of chromium or at least one light element material selected from the group consisting of oxygen (O), nitrogen (N), carbon (C), boron (B) Wherein the composition ratio of the light source to the material is 100 at%: 0 at% to 20 at%: 80 at%. 5. The method according to any one of claims 1 to 4,
Further comprising a buffer film between the capping film and the absorbing film. 5. The method according to any one of claims 1 to 4,
And a conductive film provided on a rear surface of the transparent substrate. 5. The method according to any one of claims 1 to 4,
Further comprising a polymer compound containing silicon between the resist film and a film disposed under the resist film. A photomask obtained by forming a pattern on the blank mask for extreme ultraviolet light according to any one of claims 1 to 4.

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