TWI579639B - Blankmask for extreme ultra-violet lithography and photomask using the same - Google Patents

Description

Ultraviolet lithography with a blank mask and a mask using the blank mask

The present invention relates to a blank mask for extreme ultraviolet lithography using extreme ultraviolet (EUV) rays having a wavelength of 13.5 nm as an exposure light, and a blank mask using an extreme ultraviolet lithography Extreme ultraviolet lithography with a reticle, and more specifically, by forming a sub-resolution feature size (SRFS) of 14 nm or less (especially 10 nm or A blank mask for extreme ultraviolet lithography with improved pattern accuracy and a mask for extreme ultraviolet lithography with a blank mask for extreme ultraviolet lithography.

Developed with exposure light of wavelengths of 436 nm (g line), 405 nm (h line), 365 nm (i line), 248 nm (KrF), and 193 nm (ArF) to improve resolution Use high-integration photolithography. In recent years, lithography techniques using extreme ultraviolet exposure light with a wavelength of 13.5 nm have been developed.

However, because of the exposure of 13.5 nm for extreme ultraviolet lithography Light rays have properties that are easily absorbed into most materials, including gases, and are therefore different from conventional transmission lithography techniques (eg, the use of light transmission units and light-shielding units in ArF lithography) The principle of light shielding unit), the ultra-violet lithography technique has a combination of a structure that reflects exposure light and a structure that absorbs exposure light. That is, the blank mask for extreme ultraviolet lithography is mainly composed of two parts, namely, a multilayer reflective film, and an absorption film.

In general, the multilayer reflective film has a structure in which 40 to 60 layers of molybdenum (Mo) and bismuth (Si) are alternately stacked, and has a reflectance of 64% to 66% at a wavelength of 13.5 nm. Further, the absorption film usually contains a compound containing tantalum (Ta), for example, tantalum nitride (TaN) or tantalum oxide nitride (TaON) as an ultraviolet light capable of absorbing a wavelength of 13.5 nm. The material that exposes the light. This is because the cerium (Ta) compound has an advantage of being easy to perform a plasma etching process using chlorine (Cl)-based and fluorine (F)-based radicals widely used in a semiconductor manufacturing method, This makes it possible to perform a mask manufacturing method.

However, when a pattern having a wavelength of 14 nm or less (particularly 10 nm or less) is used to realize a pattern having an absorption film containing the above-described cerium (Ta) compound, the following problems can be caused.

Figure 1 is a diagram showing the shadowing effect occurring on a reticle, which is fabricated using a conventional urethane lithography with a blank mask.

Referring to FIG. 1, a conventional ultra-violet lithography blank mask configured to form a absorbing film 106 using a tantalum (Ta) compound has a problem with respect to a shadowing effect caused by the thickness of the absorbing film 106. The term "shadowing effect" means: as it applies When the ultraviolet ray is irradiated with light to irradiate the absorbing film pattern 106a, the incident angle of the extreme ultraviolet ray exposure light is inclined with respect to the normal incidence (about 4 to 6), and the reflected light is absorbed due to the thickness of the absorbing film pattern 106a. The absorption film pattern 106a is partially prevented from shifting the reflected light. When the absorbing film 106 contains a cerium (Ta) compound, the absorbing film 106 should have a thickness of 70 nm or more, so that the absorbing film 106 can have a predetermined extinction coefficient because 钽 (Ta) is relatively Light exposure to extreme ultraviolet light has a relatively low absorption. As a result, the enhancement of the shadowing effect is also attributed to an increase in the thickness of the absorbing film 106.

Furthermore, the critical dimension (CD) deviation between the horizontal pattern (HP) and the vertical pattern (VP) may be caused by the thickness of the absorbing film 106. In particular, due to these properties, the different shadowing effects between the horizontal pattern (HP) and the vertical pattern (VP) are caused by the direction of the pattern (horizontal or vertical) and the direction of the scanner.

2A and 2B are diagrams showing the occurrence of a shadowing effect, which occurs in accordance with the direction of a pattern in a reticle fabricated using a conventional ultra-violet lithography with a blank mask.

Referring to FIGS. 2A and 2B, the shadowing effect is caused in the case of the vertical pattern (VP) as described above, but the shadowing effect is not caused in the case of the horizontal pattern (HP) because the incident light and the reflected light are parallel to The direction of the pattern. Therefore, a critical dimension deviation occurs between the vertical pattern (VP) and the horizontal pattern (HP).

Therefore, when the pattern of the absorption film formed of the tantalum (Ta) compound has a thickness of 70 nm or more, the critical dimension deviation between the horizontal pattern and the vertical pattern is confirmed to be applied to the 20 nm in the critical dimension deviation. The half pitch of the meter is about 4 nm, and it is confirmed that the critical dimension deviation is applied to 14 The half pitch of the meter is greater than or equal to about 10 nm. As a result, as the size of the pattern to be realized decreases, the critical dimension deviation increases.

Further, when the absorbing film contains a cerium (Ta) compound, the absorbing film is usually formed to have a two-layer structure (that is, an absorption layer and an anti-reflective layer), and the materials have different ingredient. More specifically, since the absorbing layer (i.e., the lower layer) constituting the absorbing film is formed of a tantalum nitride (TaN) film having a high extinction coefficient to absorb an exposure light having a wavelength of 13.5 nm, and an antireflection layer ( That is, the upper layer) is formed of a tantalum oxynitride (TaON) film for enhancing the contrast detection efficiency at a detection wavelength (for example, 193 nm or 257 nm). As such, the absorbing layer and the anti-reflective layer have different etching properties. As an example, a tantalum oxynitride (TaON) film applied as an antireflection layer has a property of being highly etchable by a fluorine gas, and a tantalum nitride (TaN) film has a property of being highly etchable by chlorine gas. Therefore, the current etching of the absorption film containing a ruthenium (Ta) compound twice by using a fluorine gas and a chlorine gas has a drawback of a troublesome process, and may gradually cause defects and impurity formation during the process. Ultimately, this problem affects product yield.

Meanwhile, the method of manufacturing a very ultraviolet lithography reticle using a blank mask using an extreme ultraviolet lithography requires an auxiliary feature pattern for optical proximity correction (OPC) (sub-resolution feature size: for example, an auxiliary strip (assist bar), etc.). The auxiliary feature pattern is a pattern formed on the reticle but not printed on the wafer, and both the auxiliary feature pattern and the main pattern require high resolution during the manufacture of the reticle. When a resist film becomes thick after being exposed (writing) to an electron beam by a super-violet lithography, it is difficult to form a fine pattern due to scattering of electrons (fine pattern) ). Therefore, the thinning of the resist film is basically required.

The invention relates to a blank mask for extreme ultraviolet lithography. Since the blank mask comprises a hard film, the ultra-violet lithography uses a blank mask to thin the resist film to form a sub-resolution feature size of 14 The pattern of meters or less than 14 nm (especially 10 nm or less) has excellent pattern accuracy, and the present invention relates to a mask using a blank mask for extreme ultraviolet lithography.

Further, the present invention relates to a photomask for extreme ultraviolet lithography, which can ensure the optical properties of the absorbing film by simultaneously adjusting the composition ratio between the metal and the light element constituting the absorbing film. Thinning of the absorbing film.

In addition, the present invention relates to a high-quality ultra-violet lithography reticle, and the high-quality ultra-violet lithography reticle can minimize the process of etching each film by making the hard film and the absorbing film have different etching properties. Etching damage applied to different films.

According to an aspect of the present invention, a blank mask for extreme ultraviolet lithography is provided, and a blank mask for an extreme ultraviolet lithography comprises a multilayer reflective film, a capping film, an absorbing film which are sequentially stacked on a transparent substrate. And a resist film. Here, the absorption film contains at least one of nickel (Ni) and nickel strontium (NiTa).

According to another aspect of the present invention, a blank mask for ultra-violet lithography is provided, and a blank mask for ultra-violet lithography comprises a reflective film, a cover film, an absorption film, and a first layer which are sequentially stacked on a transparent substrate. A functional film and a resist film. Here, the absorption film contains at least one of nickel (Ni) and nickel lanthanum (NiTa), and the first functional film serves as an etching mask for patterning the absorption film.

According to still another aspect of the present invention, a blank mask for an extreme ultraviolet lithography is provided, and a blank mask for an extreme ultraviolet lithography comprises a reflective film, a cover film, an absorbing layer, and a first layer which are sequentially stacked on a transparent substrate. An absorbing film of a two-functional film, and a resist film. Here, the absorbing layer contains at least one of nickel (Ni) and nickel lanthanum (NiTa), and the second functional film serves as an etching mask configured to pattern the absorbing layer, and remains in the second functional film for absorption It acts as an anti-reflection layer on the layer.

According to still another aspect of the present invention, a blank mask for an extreme ultraviolet lithography is provided, and a blank mask for an extreme ultraviolet lithography comprises a reflective film, a cover film, an absorbing layer, and a first layer which are sequentially stacked on a transparent substrate. An absorption film of a two-functional film, a third functional film, and a resist film. Here, the absorbing layer comprises at least one of nickel (Ni) and nickel lanthanum (NiTa), the second functional film acts as an etching mask configured to pattern the absorbing layer, and the second functional film remains on the absorbing layer It acts as an anti-reflective layer and the third functional film acts as an etch mask configured to pattern the second functional film.

In this case, the absorbing film and the absorbing layer may further comprise at least one light element selected from the group consisting of oxygen (O), nitrogen (N), carbon (C), and boron (B), and the light element is nickel ( The composition ratio of the Ni) or nickel lanthanum (NiTa) metal may be in the range of 99 at%: 1 at% to 20 at%: 80 at%.

When the absorption layer is formed to contain nickel lanthanum (NiTa), the composition ratio of the nickel lanthanum (NiTa) target may be in the range of Ni:Ta = 5 at% to 95 at%: 95 at% to 5 at%.

The absorbing film or absorbing layer and the second functional film may have a stack thickness of 30 nm to 70 nm.

The absorbing film or the absorbing layer may have a single layer or a multilayer structure such that the absorbing film or the absorbing layer may be in the form of a film having a uniform composition or a continuous film whose composition ratio continuously changes. formula.

The first functional film or the second functional film may include at least one material selected from the group consisting of chromium (Cr), tantalum (Ta), molybdenum (Mo), and antimony (Si), or may be included in addition to the material. Having at least one light element selected from the group consisting of oxygen (O), nitrogen (N), carbon (C), boron (B), and hydrogen (H), and the composition ratio of the light element to the material may be 100 atom% : 0 atom% to 20 atom%: 80 atom%.

The first functional film, the second functional film or the third functional film may have a single layer structure or a multilayer structure of two or more layers, such that the first functional film, the second functional film or the third functional film may be a single film Or in the form of a continuous film whose composition ratio varies continuously.

The first functional film, the second functional film or the third functional film may have 10 or more with respect to the absorption film, the absorption layer or the second functional film respectively disposed under the first functional film, the second functional film or the third functional film 10 etching ratio.

The first functional film or the third functional film may have a thickness of from 1 nm to 10 nm.

The second functional film may have a thickness of from 5 nm to 20 nm.

The absorbing film can have a reflectivity of less than 10% with respect to extreme ultraviolet exposure light having a wavelength of 13.5 nm.

The absorbing film can have a reflectance of less than 30% at a detection wavelength of 193 nm.

The third functional film may comprise chromium (Cr) or may comprise, in addition to chromium (Cr), a component selected from the group consisting of oxygen (O), nitrogen (N), carbon (C), boron (B), and hydrogen (H). At least one light element of the group, and the composition ratio of the light element to the material may be in the range of 100 atom%: 0 atom% to 20 atom%: 80 atom%.

The blank mask for extreme ultraviolet lithography according to the present invention may further comprise A buffer film between the cover film and the absorbing film.

The blank mask for extreme ultraviolet lithography according to the present invention may further comprise a conductive film provided in the rear surface of the transparent substrate.

The blank mask for extreme ultraviolet lithography according to the present invention may further comprise a ruthenium containing polymer compound disposed between the resist film and the film disposed under the resist film.

According to still another aspect of the present invention, there is provided a photomask for an extreme ultraviolet lithography, which is manufactured using one of a blank mask for extreme ultraviolet lithography as described above.

106a‧‧ absorbing film pattern

300‧‧‧Very UV lithography with blank mask

302‧‧‧Transparent substrate

304‧‧‧Multilayer Reflective Film

306‧‧‧ Cover film

307‧‧‧ buffer film

308‧‧‧Absorbent layer

309‧‧‧Electrical film

310‧‧‧Anti-reflective layer

312‧‧‧Absorbing film

314‧‧‧First functional film

318‧‧‧resist film

400‧‧‧Very UV lithography with blank mask

402‧‧‧Transparent substrate

404‧‧‧Multilayer reflective film

406‧‧‧ Cover film

408‧‧‧absorbing layer

412‧‧‧Absorbing film

416‧‧‧Second functional film

418‧‧‧resist film

420‧‧‧ Third functional film

HP‧‧‧ horizontal pattern

VP‧‧‧ vertical pattern

The above and other objects, features and advantages of the present invention will become more apparent from the <RTIgt In the formula: Figure 1 is a diagram showing the shadowing effect occurring on the reticle, which is manufactured using a conventional urethane lithography with a blank mask.

2A and 2B are diagrams showing the occurrence of a shadowing effect, which is a direction of a pattern in a reticle manufactured using a blank mask using conventional extreme ultraviolet lithography.

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

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

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

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

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

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

Exemplary embodiments of the present invention are described in detail below with reference to the accompanying drawings. While the invention has been shown and described with reference to the embodiments of the invention

Unless otherwise stated, all technical and scientific terms used in the specification have the same meaning as those which are generally understood by those skilled in the art to which the invention pertains. In general, the nomenclature used in the present specification and the experimental methods described below is widely known and commonly used in the related art.

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

Referring to FIG. 3, the blank mask 300 for extreme ultraviolet lithography according to the present invention comprises a transparent substrate 302, and a multilayer reflective film 304, a cover film 306, an absorbing film 312, and a resist which are sequentially stacked on the transparent substrate 302. Membrane 318.

The absorption film 312 has a multilayer structure in which an absorption layer 308 and an anti-reflection layer 310 are stacked. When the absorbing layer 308 has an anti-reflective function, the absorbing film 312 can be formed It has a single layer structure. When the absorbing film 312 has a single layer structure, the absorbing film 312 is formed of a single film having a uniform composition ratio, or may be formed in the form of a continuous film whose composition ratio varies in the thickness direction.

The transparent substrate 302 is a low thermal expansion material (LTEM) substrate having a low thermal expansion coefficient of 0±1.0×10 ^-7 /° C., preferably having a low thermal expansion coefficient of 0±0.3×10 ^-7 /° C. In order to prevent the pattern from being deformed by heat after exposure, the transparent substrate 302 can be suitably used as a glass substrate for a reflective blank mask using extreme ultraviolet light.

The substrate of low thermal expansion material needs to have high flatness to enhance the accuracy of reflected light upon exposure. The flatness is represented by a total indicated reading (TIR) value, and the total indicating reading value represents a value for determining the curvature (deformation) of the surface of the substrate, that is, is disposed in a hyperplane (hyperplane) The absolute value of the height difference between the highest position of the surface of the substrate on the plane determined based on the surface of the substrate by the least square method and the lowest position of the surface of the substrate disposed under the hyperplane. Therefore, as the flatness increases, the total indication reading decreases. Therefore, the low thermal expansion material substrate preferably has a low total indicator reading value.

The flatness of the substrate of the low thermal expansion material affects the flatness of the multilayer reflective film and the cover film formed on the substrate of the low thermal expansion material, and the flatness of the absorption film. In particular, when the flatness on the reflective film and the cover film is low (the reflective film and the cover film have high total indication reading values), the extreme ultraviolet exposure light is obliquely incident at an angle of about 4 to 6 to make The position distortion of the pattern is caused when the illuminator transmits extreme ultraviolet light. Therefore, the flatness of the substrate (total indication reading value) is preferably desirably "0", but it is difficult to achieve "0" due to actual processing (for example, mechanical processing such as polishing, partial grinding, etc.) Indicating reading value. Thus, the low thermal expansion material substrate has a flatness of 60 nanometers or less (total indication reading value), preferably 40 nanometers or less than 40 nanometers.

The multilayer reflective film 304 is formed by alternately stacking 40 to 60 molybdenum (Mo) layers and a bismuth (Si) layer. The multilayer reflective film 304 needs to have a high reflectance at a wavelength of 13.5 nm in order to improve image contrast. This reflection intensity of the multilayer reflective film varies depending on the incident angle of the exposure light and the thickness of each layer. For example, when the incident angle of the exposure light is 5°, the molybdenum (Mo) layer and the bismuth (Si) layer may be formed to have thicknesses of 2.8 nm and 4.2 nm, respectively. However, as the angle of incidence is widened to 8° to 14° when applied to extreme ultraviolet immersion lithography, the intensity of the reflection changes. Therefore, the reflective film 304 must have a reflection intensity that is optimized for the final incident angle of the exposure light. In this case, the molybdenum (Mo) layer has a thickness of 2 nm to 4 nm, and the bismuth (Si) layer has a thickness of 3 nm to 5 nm.

Since the multilayer reflective film 304 is easily oxidized when molybdenum (Mo) is in contact with air, the reflectance may be deteriorated. Therefore, a bismuth (Si) layer is preferably formed on the uppermost layer as a protective film configured to prevent oxidation. The reflective film 304 has a reflectance of 65% or more at a very ultraviolet exposure wavelength of 13.5 nm and a reflectance of 40% to 65% at a detection wavelength of 193 nm or 257 nm. The reflective film 304 has an absolute value of the total surface indication reading of 60 nanometers or less, preferably having an absolute value of the total surface indication reading of 40 nanometers or less. The reflective film 304 has a surface roughness of 0.2 nm root mean square (nmRMS) or less than 0.2 nm root mean square, preferably having a surface of 0.1 nm root mean square or less than 0.1 nm root mean square Roughness.

The cover film 306 comprises a layer selected from the group consisting of ruthenium (Ru), titanium (Ti), molybdenum (Mo), tantalum (Ta), vanadium (V), cobalt (Co), nickel (Ni), zirconium (Zr), and niobium (Nb). ),palladium (Pd), zinc (Zn), chromium (Cr), aluminum (Al), manganese (Mn), cadmium (Cd), magnesium (Mg), lithium (Li), selenium (Se), copper (Cu), antimony At least one material of the group consisting of (Hf), tungsten (W), and bismuth (Si), or in addition to the inclusion material, further comprising an oxygen (O), nitrogen (N), carbon (C), and boron ( B) at least one material of the group consisting of.

In this case, the cap film 306 is formed of ruthenium (Ru) and niobium (Nb), or a ruthenium (Ru) compound and a niobium (Nb) compound. Further, the cover film 306 may be formed of a compound containing ruthenium (Ru) and niobium (Nb). The content of light elements (the sum of the contents of oxygen (O), nitrogen (N), carbon (C), and boron (B)) is in the range of 10:0 to 5:5 with respect to the metal.

The cover film 306 has a thickness of from 1 nm to 10 nm, preferably from 1 nm to 5 nm. When the thickness of the cap film 306 is less than or equal to 1 nm, it is difficult to protect after forming a pattern on the absorbing film formed on the cap film 306 in consideration of etching conditions (for example, over-etching or the like). The reflective film 304 is formed under the cover film 306. Furthermore, when the thickness of the cover film 306 is greater than or equal to 10 nm, the cover film 306 has a reflectance of less than 60% at an exposure wavelength of 13.5 nm, and thus, with respect to the reflectance of the absorption film 312 The image contrast can be degraded, and the final detected contrast relative to the absorbing film can also be degraded due to low reflectance at the detection wavelength (eg, 193 nm or 257 nm), which makes detection difficult to perform. .

The cover film 306 has a reflectance of 60% or greater at a very ultraviolet exposure wavelength of 13.5 nm and has an absolute value of the total surface indication reading of 60 nm or less, preferably 40 nm or A surface total of less than 40 nm indicates the absolute value of the reading. The cover film 306 has a surface roughness of 0.2 nm root mean square or less than 0.2 nm root mean square, preferably having a root mean square of 0.1 nm or less than 0.1 nm square. The surface roughness of the root.

The absorption film 312 is selected from the group consisting of nickel (Ni), tellurium (Te), tin (Sn), palladium (Pd), selenium (Se), tungsten (W), antimony (Os), antimony (Ir), antimony (Sb). At least one material of the group consisting of cerium (Si) and cerium (Ta), or in addition to at least one material, further comprising oxygen (O), nitrogen (N), carbon (C), boron (B) And at least one material of the group consisting of hydrogen (H).

In addition to reducing the angle of incidence of the light source, it is also desirable to thin the thickness of the absorbing film 312 in order to reduce the shadowing effect caused by exposure with the reticle by the extreme ultraviolet lithography. Among these, the constituent material having a high extinction coefficient with respect to the exposure light exhibits excellent etching properties and etching selectivity to the cap film 306 formed under the absorption film 312, and is used for realizing the thickness of the absorption film 312. The chemicals used for the rinsing required for thinning are extremely resistant. The tantalum (Ta) currently used has an extinction coefficient of 0.0408 at an exposure wavelength of 13.5 nm, and an absorption film containing tantalum (Ta) as a main component needs to have a thickness of 70 nm or more to satisfy absorption. The specific reflectivity of the film.

According to the present invention, the absorption film 312 is formed of a nickel (Ni) or nickel (Ni) compound. Here, since nickel (Ni) has an extinction coefficient of 0.0727 at an exposure wavelength of 13.5 nm, the absorption film 312 can be thinned to a thickness of 70 nm or less to satisfy the same degree of reflectance. Further, for the etching property of the absorption film 312 containing nickel (Ni), among nickel (Ni) compounds, nickel nitride (NiN) may have excellent dry etching properties, and an amorphous film is realized to maintain the pattern. Excellent nature.

When the absorbing film 312 is formed of a nickel (Ni) or nickel lanthanum (NiTa) compound, the absorbing film 312 may further comprise an object selected from the group consisting of oxygen (O), nitrogen (N), carbon (C), and boron (B). And light elements of the group consisting of hydrogen (H) to improve dry etching properties. In this case, the absorption film 312 has a light element (at least one of oxygen (O), nitrogen (N), carbon (C), boron (B), and hydrogen (H)) to nickel (Ni) or nickel. The ratio of cerium (NiTa) may be a composition ratio in the range of 95 atom%: 5 atom% to 20 atom%: 80 atom%. Further, when the absorption film 312 is formed to contain nickel lanthanum (NiTa), the nickel lanthanum (NiTa) target has a composition ratio of Ni:Ta = 5 at% to 95 at%: 95 at% to 5 at%.

The absorption film 312 needs to have a low reflectance of 25% or less at a detection wavelength (193 nm or 257 nm) to exhibit a difference in reflectance (contrast) between the absorption film 312 and the multilayer reflection film 304. For example, when the absorption film 312 has a multilayer structure of the absorption layer 308 and the anti-reflection layer 310, the anti-reflection layer 310 contains oxygen (O) and nitrogen (N) in addition to nickel (Ni) or nickel niobium (NiTa). And it is possible to reduce the reflectance at the detection wavelength. Further, the absorption layer 308 has a low oxygen (O) content compared to the anti-reflection layer 310 to enhance the light absorption rate and achieve thinning. Therefore, the absorption layer 308 includes one of nickel nitride (NiN) and nickel tantalum nitride (NiTaN), and the anti-reflection layer 310 includes nickel oxide nitride (NiON) and nickel oxynitride. One of (nickel tantalum oxide nitride, NiTaON). Since all of the nickel nitride (NiN), nickel nitride (NiTaN), nickel oxynitride (NiON), and nickel oxynitride (NiTaON) constituting the absorption film 312 of the present invention are etched using chlorine (Cl) gas, the process is performed. This is simple because the absorbing film 312 can be etched through a single etching process, and defects and formation of impurities can be reduced.

In addition, when the absorbing film 312 has a single layer structure, the absorbing film 312 containing nickel (Ni) or nickel lanthanum (NiTa) as a main component is formed in the form of a continuous film. The content of oxygen (O) and nitrogen (N) may be increased in the upward direction of the continuous film, and the content of oxygen (O) may be decreased in the downward direction of the continuous film. As a result, it is possible to reduce the reflectance at the detection wavelength and enhance the light absorption rate.

The absorbing film 312 has a thickness of 30 nm to 70 nm. When the thickness of the absorption film 312 is less than or equal to 30 nm, the absorption film 312 has a high reflectance of 10% or more with respect to the exposure light. On the other hand, when the thickness of the absorbing film 312 is greater than or equal to 70 nm, the desired deviation from the critical dimension may be increased due to the high critical dimension deviation between the horizontal pattern and the vertical pattern, which causes uniformity of the critical dimension. Sexual and mask-enhanced error factor (MEEF) increases.

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

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

Further, although not shown, a ruthenium-containing polymer compound coated to improve adhesion to the resist film may be formed on the film disposed under the resist film 318, for example, anti-reflection formed on the absorption film 312. On layer 310. Antimony polymer compound At least one selected from the group consisting of hexamethyldioxane, trimethyldecyldiethylamine, O-trimethyldecyl acetate, O-trimethyldecyl propionate, O-trimethyldecanoate butyrate, trimethyldecyl trifluoroacetate, trimethylmethoxydecane, N-methyl-N-trimethyldecyltrifluoroacetamide, O-trimethyl Alkyl acetonitrile, isopropenyloxytrimethylnonane, trimethyldecyltrifluoroacetamide, methyltrimethyldecyl dimethyl ketone acetate, and trimethylethoxydecane.

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

Referring to FIG. 4, the blank mask for extreme ultraviolet lithography according to the present invention comprises a transparent substrate 302, and a multilayer reflective film 304, a cover film 306, an absorbing film 312, and a first functional film which are sequentially stacked on the transparent substrate 302. 314 and a resist film 318. Here, the multilayer reflective film 304, the cap film 306, and the absorbing film 312 containing nickel (Ni) or nickel lanthanum (NiTa) have the same configuration as that described in the first exemplary embodiment.

The first functional film 314 is formed of a material having an etching property different from that of the absorption film 312 as an etching mask configured to pattern the absorption film 412 disposed under the first functional film 314. The functional film 314 has an etch selectivity of 1:10 or greater than 1:10 with respect to the absorbing film 312, preferably having an etch selectivity of 1:20 or greater than 1:20. That is, the first functional film 314 can be etched using a chlorine (Cl)-based gas because the absorption film 312 contains nickel nitride (NiN), nickel nitride (NiTaN), nickel oxynitride (NiON), or nitrogen. Nickel oxide niobium (NiTaON). Therefore, the first functional film 314 can be formed of a material that can be etched by a fluorine (F)-based gas. For this purpose, the first functional film 314 comprises a layer selected from the group consisting of chromium (Cr), tantalum (Ta), bismuth (Si), ruthenium (Ru), titanium (Ti), molybdenum (Mo), tungsten (W), and molybdenum telluride. At least one material of the group consisting of (MoSi), or in addition to comprising at least one material, further comprising an oxygen (O), At least one material of the group consisting of nitrogen (N), carbon (C), boron (B), and hydrogen (H). In this case, the functional film 314 has a composition ratio such that the ratio of the light element to the metal may be in the range of 100 atom%: 0 atom% to 20 atom%: 80 atom%.

The first functional film 314 is formed into a multilayer structure having a single layer structure or two or more layers. When the first functional film 314 is formed in a single layer structure, the first functional film 314 may be formed in the form of a continuous film in which the composition ratio is continuously changed, or in the form of a single film having a uniform composition after sputtering. . Furthermore, the first functional film 314 has an amorphous structure.

The first functional film 314 needs to have a small thickness and a fast etching rate to achieve thinning of the resist film 318. For this purpose, the functional film 314 has a thickness of from 1 nm to 10 nm, preferably from 3 nm to 5 nm.

The first functional film 314 is removed during the reticle manufacturing process, and the first functional film 314 is retained as necessary to enhance the role as an anti-reflective layer.

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

Referring to FIG. 5, a blank mask 400 for extreme ultraviolet lithography according to the present invention includes a transparent substrate 402, and a multilayer reflective film 404, a cover film 406, an absorbing layer 408, and a second layer, which are sequentially stacked on the transparent substrate 402. An absorbing film 412 of the functional film 416, and a resist film 418. Here, the multilayer reflective film 404, the cap film 406, and the absorbing layer 408 have the same configuration as that described above in the first exemplary embodiment.

The second functional film 416 is an etch mask that serves as the absorbing layer 408 and also remains on the pattern of the absorbing layer 408 after patterning the absorbing layer 408, thereby acting as an anti-reflective layer. Thus, the absorber layer 408 typically exhibits improved light absorption, And has a low oxygen (O) content for thinning purposes. For this purpose, the absorber layer 408 is formed of one of nickel nitride (NiN) and nickel nitride (NiTaN).

The absorbent layer 408 has a thickness of from 20 nanometers to 50 nanometers, and an absolute value of the total surface indication reading of 60 nanometers or less, preferably 40 nanometers or less. Absolute value. The absorbent layer 408 has a surface roughness of 0.2 nm root mean square or less than 0.2 nm root mean square, preferably having a surface roughness of 0.1 nm root mean square or less than 0.1 nm root mean square.

The second functional film 416 has an etch selectivity of 1:10 or greater than the absorption layer 408 as an etch mask. That is, the second functional film 416 may be etched with a chlorine (Cl)-based gas because the absorption layer 408 contains nickel nitride (NiN) or nickel nitride (NiTaN). Therefore, the second functional film 416 can be formed of a material that can be etched with a fluorine (F)-based gas. For this purpose, the second functional film 416 comprises a layer selected from the group consisting of chromium (Cr), tantalum (Ta), bismuth (Si), ruthenium (Ru), titanium (Ti), molybdenum (Mo), tungsten (W), and molybdenum telluride. At least one material of the group consisting of (MoSi), or in addition to comprising at least one material, further comprising a component selected from the group consisting of oxygen (O), nitrogen (N), carbon (C), boron (B), and hydrogen (H). At least one material of the group. In this case, the second functional film 416 has a composition ratio such that the ratio of the light element to the metal may be in the range of 100 atom%: 0 atom% to 20 atom%: 80 atom%.

The second functional film 416 desirably has a fast etch rate and a small thickness for thinning of the resist film 418, but needs to have a predetermined thickness for the anti-reflection function. For this purpose, the second functional film 416 has a thickness of from 5 nm to 20 nm, preferably from 10 nm to 15 nm.

The absorption film 412 stacked with the absorption layer 408 and the second functional film 416 has a reflectance of less than 10% with respect to the extreme ultraviolet exposure light having a wavelength of 13.5 nm. It preferably has a reflectance of 5% or less, and more preferably has a reflectance of 1% or less. Further, the absorbing film 412 has a reflectance of less than 30% at a detection wavelength of 193 nm, preferably a reflectance of 25% or less.

The chemically amplified resist is used as the resist film 418, and the resist film 418 has a thickness of 150 nm or less, preferably 100 nm or less, and more Preferably, the ground has a thickness of 80 nm or less.

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

Referring to FIG. 6, a blank mask 400 for extreme ultraviolet lithography according to the present invention includes a transparent substrate 402, and a multilayer reflective film 404, a cover film 406, an absorbing layer 408, and a second, which are sequentially stacked on the transparent substrate 402. The absorption film 412 of the functional film 416, the third functional film 420, and the resist film 418. Here, similarly to the above-described third exemplary embodiment, the multilayer reflective film 404, the cover film 406, and the absorption layer 408 have the same configuration as that described above in the first exemplary embodiment, and the second Functional film 416 is configured to function as an etch mask and an anti-reflective layer.

The third functional film 420 serves as an etching mask for the second functional film 416. For this purpose, the third functional film 420 is formed of a material having an etching selectivity of 1:10 or greater than 1:10 with respect to the second functional film. That is, the third functional film 420 preferably includes a material which has excellent etching resistance with respect to the fluorine (F)-based gas which is the etching gas of the second functional film 416 and which can be etched using a chlorine (Cl)-based gas. Thus, for example, the third functional film 420 is formed of a chromium (Cr) compound containing a light element such as oxygen (O), nitrogen (N), carbon (C), boron (B), and hydrogen (H).

The third functional film 420 is formed in a single layer structure or a multilayer structure of two or more layers. When the third functional film 420 is formed in a single layer structure, the third The functional film 420 may be formed in the form of a continuous film in which the composition ratio is continuously changed, or in the form of a single film having a uniform composition after sputtering. Furthermore, the third functional film 420 has an amorphous structure.

The third functional film 420 is required to have a fast etching rate for thinning of the resist film 418. For this purpose, the third functional film 420 has a thickness of from 1 nm to 10 nm, preferably from 3 nm to 5 nm.

The third functional film 420 is removed during the reticle manufacturing process, and the third functional film 420 is retained as necessary to enhance the anti-reflective character of the second functional film 416.

A chemically amplified resist (CAR) is used as the resist film 418, and the resist film 418 has a thickness of 150 nm or less, preferably 100 nm or less. And more preferably having a thickness of 60 nm or less.

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

Referring to FIG. 7, the blank mask 300 for extreme ultraviolet lithography according to the present invention may further include a buffer film 307 disposed between the cover film 306 and the absorbing film 312. The buffer film 307 serves to prevent the multilayer reflective film 304 from being damaged during the dry etching process of forming the pattern of the absorbing film 312. Further, the buffer film 307 serves to protect the multilayer reflective film 304 in a repair process performed when a dark color defect and a white defect occur on the pattern of the absorbing film during the urethane photomask manufacturing process.

The buffer film 307 is formed of a material having an etching selectivity with respect to the absorption film 312 (for example, a chromium (Cr)-based compound, and the pattern of the buffer film 307 in the absorption film is corrected using a focused ion beam (FIB). Preferably, it has a thickness of 20 nm to 60 nm, and the focused ion beam (FIB) is not used to correct the pattern of the absorption film (to use an electron beam in an unexcited state and a fluorine-based gas (Xe ₂ F, etc.) It is preferable to have a thickness of 5 nm to 15 nm when the defect is corrected (EB correction).

When the buffer film 307 is not formed in the ultra-violet lithography blank mask 300 according to the present invention, the cover film 306 can be imparted with the function of the buffer film 307.

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

Referring to FIG. 8, the blank mask 300 for extreme ultraviolet lithography according to the present invention may further include a conductive film 309 provided in the rear surface of the transparent substrate 302. The conductive film 309 is selectively formed on the rear surface of the substrate of the low thermal expansion material. In this case, the conductive film 309 may be formed on the rear surface of the low thermal expansion material substrate after the multilayer reflective film 304, the cover film 306, and the absorption film 312 are formed on the low thermal expansion material substrate, or may be on the multilayer reflective film 304, The cover film 306 and the absorption film 312 are preferentially formed on the rear surface of the low thermal expansion material substrate before being formed on the low thermal expansion material substrate. The conductive film 309 is used to assist in the combination of an electrostatic chuck and an ultra-violet lithography with a blank mask, and has a low sheet resistance to improve the adhesion to the electrostatic chuck. The conductive film 309 is used to prevent particles from being formed in the conductive film due to friction between the electrostatic chuck and the conductive film by improving the close adsorption of the ultra-violet lithography to the electrostatic chuck by the blank mask. Therefore, the conductive film has a sheet resistance value of 100 Ω / □ or less, preferably 50 Ω / □ or less than 50 Ω / □, and more preferably 20 Ω / □ or less than 20 Ω / □ resistance.

The conductive film 309 is selected from the group consisting of titanium (Ti), molybdenum (Mo), tantalum (Ta), vanadium (V), cobalt (Co), nickel (Ni), zirconium (Zr), niobium (Nb), palladium (Pd). , zinc (Zn), Chromium (Cr), aluminum (Al), manganese (Mn), cadmium (Cd), magnesium (Mg), lithium (Li), selenium (Se), copper (Cu), hafnium (Hf), tungsten (W), and At least one material of the group consisting of cerium (Si), or in addition to the material comprising at least one material selected from the group consisting of oxygen (O), nitrogen (N), carbon (C), and boron (B) .

The conductive film 309 has a thickness of 70 nm or less and may be formed in the form of a single film composed of a single layer, in the form of a continuous film composed of a single layer, or in the form of 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 can be formed of chromium (Cr) contained as a main component. When the conductive film 309 is formed in the form of a two-layered multilayer film, the conductive film 309 may be formed such that the lower layer contains chromium (Cr) and nitrogen (N), and the upper layer contains chromium (Cr), nitrogen ( N) and oxygen (O). In this case, the conductive film 309 has a ratio such that the ratio of chromium (Cr) to light elements (the sum of oxygen (O), nitrogen (N), carbon (C), and boron (B)) is 8:2 to 2 A ratio of components within the range of :8.

In addition, although not shown, the blank mask for extreme ultraviolet lithography according to the present invention may include all buffer films, conductive films, and ruthenium containing polymer compounds, or may optionally include a buffer film, a conductive film, and a ruthenium containing polymer compound. .

In addition, the multilayer reflective film, the cover film, the absorption film, the functional film, the buffer film, and the conductive film may be subjected to thermal treatment as the case may be, and may be selected from a rapid thermal process (RTP), a vacuum hot plate. At least one of a group consisting of a vacuum hot-plate baking, a plasma process, and a furnace process performs a heat treatment process.

Hereinafter, an exemplary embodiment in accordance with the present invention will be described in further detail. The extreme ultraviolet lithography of the example uses a blank mask.

Instance Evaluation of a blank mask with extreme ultraviolet lithography containing an absorbing film in which nickel (Ni) is formed

In order to manufacture a UV mask for ultra-violet lithography, the preparation size is 6吋×6吋×0.25吋 and the flatness (total reading value) is controlled to 60 nm or less and formed of SiO ₂ -TiO component. A low thermal expansion material (LTEM) substrate is used as the substrate.

A conductive film containing chromium (Cr) as a main component is formed on the rear surface of the substrate of the low thermal expansion material using a DC magnetron reactive sputtering system. The conductive film has a two-layer structure in which chromium nitride (CrN; lower layer) and chromium oxynitride (CrON; upper layer) are formed. The upper layer and the lower layer of the conductive film are formed of a chromium (Cr) target, and a lower portion of the conductive film is formed by injecting a process gas at a flow ratio of Ar:N ₂ =5 sccm:5 sccm and applying a processing power of 1.4 kW. The layer was a chromium nitride (CrN) film having a thickness of 42 nm. Further, an upper layer of a conductive film was formed by injecting a process gas at a flow rate ratio of Ar:N ₂ :NO=7 sccm:7 sccm:7 sccm and applying a treatment power of 1.4 kW as chromium oxynitride (CrON) having a thickness of 24 nm. )membrane. Finally, the conductive film was formed to have a thickness of 66 nm, and a four-point probe was used to measure the sheet resistance of the formed conductive film. As a result, it was confirmed that the conductive film had a sheet resistance value of 16.5 Ω/□, and thus there was no problem associated with the bonding (E-clamping) of the electrostatic chuck.

40 molybdenum (Mo) are alternately formed on the entire surface of the low thermal expansion material substrate by using an ion beam deposition-low defect density (hereinafter referred to as "IBD-LDD") system. The layer and the bismuth (Si) layer are such that the molybdenum (Mo) layer and the bismuth (Si) layer have a thickness of 4.8 nm and 2.2 nm, respectively, to form a multilayer reflective film. The reflectance of the multilayer reflective film was measured using an extreme ultraviolet reflectometer. The measurement revealed that the multilayer reflective film had a reflectance of 67.8% at a wavelength of 13.5 nm and a reflectance of 64.66% at a wavelength of 193 nm. Next, the surface roughness of the multilayer reflective film was measured using an atomic force microscopy (AFM) system. The measurement results revealed that the multilayer reflective film had a surface roughness of 0.12 nm root mean square, and a diffuse reflection of the extreme ultraviolet exposure light slightly occurred due to the surface roughness when the extreme ultraviolet exposure light was reflected on the multilayer reflective film. Furthermore, an ultra-flat system was used to measure the flatness of the 142 mm square region of the multilayer reflective film. From the results, it was found that the multilayer reflective film had a total indication reading value of 54 nm, which indicates that the positional distortion of the pattern was slightly affected by the reflection film.

A cover film was formed by stacking ruthenium (Ru) onto a multilayer reflective film to a thickness of 2.5 nm using an IBD-LDD system. After the cap film was formed, the reflectance of the cap film was measured in the same manner as in the multilayer reflective film. The results revealed that the cover film had a reflectance of 65.8% at a wavelength of 13.5 nm, and thus there was no change with respect to the reflectance of 67.8% which is a multilayer reflective film. Next, the reflectance of the cover film was measured at a wavelength of 193 nm. The results revealed that the cover film had a reflectance of 55.43%. Again, the surface roughness and flatness of the cover film were measured in the same manner as described above. As a result, it was confirmed that the cover film had a surface roughness value of 0.13 nm root mean square, and thus there was no change with respect to the multilayer reflective film, and the cover film also had a total indication reading value of 54 nm, and thus relative to the multilayer reflection There is no change in the membrane.

A nickel magnetron reactive sputtering system having a double layer structure having an absorption layer and an antireflection layer was formed on the cover film using a DC magnetron reactive sputtering system. The two layers of the absorbing film were formed of a nickel (Ni) target, and nitrogen was formed to a thickness of 30 nm by injecting a process gas at a flow ratio of Ar:N ₂ =8 sccm:2 sccm and applying a processing power of 1.0 kW. A nickel (NiN) layer is used as the lower absorption layer. Under this circumstance, it was revealed that the lower absorption layer had a reflectance of 1.6% at an exposure wavelength of 13.5 nm.

The upper anti-reflection layer was formed as a nickel oxynitride (NiON) layer having a thickness of 12 nm by injecting a process gas at a flow rate ratio of Ar:N ₂ :NO=5 sccm:5 sccm:3 sccm and applying a treatment power of 1.0 kW. The reflectance of the upper anti-reflective layer was measured similarly in the absorption layer at an exposure wavelength of 13.5 nm. The measurement revealed that the upper antireflection layer had a reflectance of 0.9% and also had a reflectance of 22.3% at a wavelength of 193 nm, which indicates that the upper antireflection layer exhibited excellent reflectance at the detection wavelength.

The flatness of the absorption film containing nickel (Ni) was measured using an ultra-flat system. The results revealed that the absorbing film had a total indicator reading of 70 nm, which indicates a slight increase in the total indication reading value of 16 nm compared to the total indicated reading value measured after forming the hood film. The change, but when using the change in the total indicated reading value to calculate the film stress, the absorbent film has a normal film stress of about 150 megapascals.

Furthermore, the AES system was used to analyze the composition ratio according to the depth of the absorbing film. As a result, it was revealed that nickel (Ni) and light elements (O, N) were present in a ratio of 4:6 in the case of the upper antireflection layer, and nickel (Ni) and light elements in the case of the lower absorption layer. (N) exists in a composition ratio of 8:2.

Evaluation of a blank mask with extreme ultraviolet lithography containing an absorbing film formed of nickel (Ni) and tantalum (Ta)

Evaluating the tool in the same manner as described above in the blank mask having an ultra-violet lithography comprising an absorbing film formed with nickel (Ni) as a main component There is a blank mask for extreme ultraviolet lithography containing an absorbing film formed with nickel (Ni) and tantalum (Ta) as main components. Here, the lower film other than the absorption film has the same configuration as that of the above-described ultra-violet lithography blank mask having an absorption film formed of nickel (Ni) as a main component.

A DC magnetron reactive sputtering system was used to form the absorption film in a two-layer structure containing nickel niobium (NiTa). Both layers of the absorbing film are formed by a nickel ruthenium (NiTa) target (Ni: Ta = 90 atom%: 10 atom%, 70 atom%: 30 atom%, 50 atom%: 50 atom% or 10 atom% : composition ratio of 90 atom%). In this case, a Ni-NiN layer having a thickness of 31 nm was formed as a lower absorption layer by injecting a process gas at a flow rate ratio of Ar:N ₂ =8 sccm:2 sccm and applying a treatment power of 1.0 kW. Next, a NiTaON layer having a thickness of 14 nm was formed as an upper anti-reflection by injecting a process gas at a flow rate ratio of Ar:N ₂ :NO=5 sccm:5 sccm:3 sccm and applying a treatment power of 1.0 kW. Floor.

The reflectance of each layer of the absorbing film was measured using an extreme ultraviolet reflectometer. The measurement revealed that the absorbing film layer had 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 a detection wavelength of 193 nm.

Comparison of a blank mask with extreme ultraviolet lithography containing an absorbing film formed with ruthenium (Ta) as a main component

In Comparative Example 1, a blank mask having an ultraviolet ray lithography including an absorbing film formed with ruthenium (Ta) as a main component was produced, and the properties of the blank mask for the extreme ultraviolet lithography were compared with the inclusion of nickel formed therein. The above-mentioned extreme ultraviolet lithography of the absorbing film of (Ni) or nickel lanthanum (NiTa) as a main component is a property of a blank mask. Here, in addition to the absorption film, the lower film has and contains nickel (Ni) as a main component The above-described extreme ultraviolet lithography of the absorbing film of the component is configured in the same configuration as the blank mask.

A DC magnetron reactive sputtering system is used to form the absorption film in a two-layer structure comprising tantalum (Ta). Both layers of the absorbing film are formed from a group (Ta) target. In this case, a tantalum nitride (TaN) layer was formed as a lower absorption layer by injecting a process gas at a flow rate ratio of Ar:N ₂ =8 sccm:2 sccm and applying a treatment power of 1.0 kW. Next, the thickness of a region of the lower absorption layer having a reflectance of 1.5% was measured at an exposure wavelength of 13.5 nm. The results revealed that the lower absorbent layer had a thickness of 55 nm. Next, a ruthenium oxynitride (TaON) layer was formed as an upper anti-reflection layer by injecting a process gas at a flow rate ratio of Ar:N ₂ :NO=5 sccm:5 sccm:3 sccm and applying a treatment power of 1.0 kW. The results revealed that the region of the upper antireflection layer having a reflectance of 1.0% at an exposure wavelength of 13.5 nm had a thickness of 15 nm. Therefore, it can be seen that the entire thickness of the absorbent film is 70 nm, which is thicker than the thickness of the absorbent film according to the present invention.

The film component ratio of the light element to the metal, the thickness and the reflectance of the above-mentioned absorption film containing nickel (Ni), nickel lanthanum (NiTa), and tantalum (Ta) are listed in Table 1 below.

As listed in Table 1, it can be seen that when the absorbing film is formed of nickel (Ni) or nickel lanthanum (NiTa) (as described above in Examples 1 to 5), it satisfies the relative wavelength of 13.5 nm and is detected. The thickness of the absorption film required for the same reflectance of light having a wavelength of 193 nm is smaller than the thickness of a conventional absorption film (Comparative Example 1) formed of tantalum (Ta).

Manufacture and evaluation of blank masks for extreme UV lithography containing the first functional film

The conductive film, the multilayer reflective film, the cover film, and the absorption film containing nickel (Ni) as a main component are formed on the substrate of the low thermal expansion material in the same manner as described in the blank mask of the extreme ultraviolet lithography, A DC magnetron reactive sputtering system is then used to form the first functional film on the absorbent film. By using a cerium (Si) target doped with boron (B) (component ratio of Si:B=98:2 to 80:20), a flow ratio of Ar:N ₂ :NO=5sccm:3sccm:2sccm is injected. The process gas was applied and a processing power of 0.6 kW was applied to form a first functional film as a silicon nanotube oxynitride (SiBON) film having a thickness of 4 nm.

Under this circumstance, it was revealed that the first functional film had a reflectance of 0.85% at an exposure wavelength of 13.5 nm. Next, the flatness of the first functional film is measured using an ultra-flat system. The results revealed that the first functional film had a total indicator reading of 77 nm. Furthermore, the AES system was used to analyze the composition ratio of the first functional film. As a result, it was revealed that the first functional film had a composition ratio of Si:B:O:N=72 atom%: 3 atom%: 10 atom%: 15 atom%.

Subsequently, the ruthenium containing polymer compound is doped with hexamethyldioxane to improve the adsorption of the resist film of the first functional film, and the chemically amplified resist film is formed to have a thickness of 80 nm to be manufactured. Extreme UV lithography with a blank mask.

Manufacture and evaluation of reticle for ultra-violet lithography containing first functional film

Use UV lithography to create and evaluate extreme UV rays with a blank mask A lithography reticle in which a first functional film is used as an etch mask.

A 50 keV writing machine was used to expose the extreme ultraviolet lithography with a blank mask, and the pattern was formed on the resist film via post-exposure baking (PEB) and development. Thereafter, the functional film formed of boron oxynitride (SiBON) is etched by the etching gas through the pattern of the resist film for 30 seconds (in consideration of the time in the case of over etching), and the etching gas contains fluorine (F) Base gas SF ₆ gas. In this case, the thickness of the residual resist film was measured. The results revealed that the residual resist film had a thickness of 30 nm and thus effectively served as an etching mask.

Next, the residual resist film is removed, and the absorbing film is etched through the patterned first functional film serving as an etching mask using an etching gas containing chlorine (Cl). After the etching, the thickness of the first functional film is measured. As a result, it was revealed that the first functional film had a thickness of 3.0 nm, and thus had an etching selection ratio of 20 or more, which indicates an etching selectivity ratio of 1:50 (functional film: absorption film).

Subsequently, the first functional film is removed to manufacture a photomask for extreme ultraviolet lithography.

The resolution of the reticle for extreme ultraviolet lithography according to the present invention was measured using a scanning electron microscopy (SEM). The results revealed that the iso-space pattern was defined as a depth of 40 nm. Next, the critical dimension linearity of the reticle for the extreme ultraviolet lithography was measured in the range of 60 nm to 1,000 nm. The results reveal that the ultra-violet lithography mask has a high critical dimension linearity of 2.3 nm, 3.0 nm, and 3.2 nm in the same pattern of iso-line pattern, line and space pattern, and the same spatial pattern. value.

Manufacture and evaluation of a mask for extreme ultraviolet lithography without a functional film and a mask for extreme ultraviolet lithography using a blank mask for extreme ultraviolet lithography

In Comparative Example 1, a blank mask having an ultraviolet ray lithography comprising an absorbing film formed with ruthenium (Ta) as a main component was produced, and the properties of a blank mask for extreme ultraviolet lithography and formation according to the present invention were compared. There is a property of a blank mask with an absorbing film and an extreme ultraviolet lithography of the first functional film. Here, the absorbing film contains nickel (Ni) or nickel lanthanum (NiTa) as a main component, and the first functional film serves as an etching mask.

In order to satisfy the exposure and detection conditions at an exposure wavelength of 13.5 nm and 193 nm in a blank mask having an ultraviolet lithography containing an absorbing film formed with ruthenium (Ta) as a main component, by forming an absorption The layer was formed as a tantalum nitride (TaN) layer having a thickness of 55 nm and an antireflection layer was formed as a lanthanum oxynitride (TaON) layer having a thickness of 15 nm to form the absorption film to have a total thickness of 70 nm, as above It is described in Comparative Example 1.

Next, a chemically amplified resist film was applied to a thickness of 80 nm, an electron beam type resist film was exposed using an electron beam writer, and then the chemically amplified resist film was subjected to post-exposure baking. Bake and develop to form a pattern of the resist film. Thereafter, the upper anti-reflection layer formed of tantalum oxynitride (TaON) in the absorption film is etched by using SF ₆ gas through a pattern of a resist film used as an etching mask, and etching is performed using tantalum nitride using Cl ₂ gas ( TaN) forms a lower absorbent layer. Next, the thickness of the residual resist film was measured. As a result, it was revealed that no residual resist film was observed, and the upper portion of the pattern of the absorption film was damaged by etching. Subsequently, the chemically amplified resist film was applied to a thickness of 120 nm, and the absorption film was etched in the same manner as described above. From the results, it can be seen that the residual resist film has a thickness of 20 nm, which indicates a pattern in which the absorption film is formed without damage.

Subsequently, critical-scale scanning electron microscopy was used to measure the resolution of the reticle for extreme ultraviolet lithography. The results reveal that the same spatial pattern is defined as a depth of 60 nm. degree. Next, the critical dimension linearity of the reticle for the extreme ultraviolet lithography was measured in the range of 60 nm to 1,000 nm. The results reveal that the extreme ultraviolet lithography mask has a high critical dimension linear value of 4.5 nm, 7.5 nm, and 5.2 nm in the same line pattern, line and space pattern, and the same spatial pattern, respectively. The result of the linear value is inferior to the result of the reticle for the extreme ultraviolet lithography according to the present invention.

Evaluation of the physical properties and chemical properties of the first functional film based on the constituent materials

In the manufacture of the blank mask for extreme ultraviolet lithography according to the present invention, the physical properties and chemical properties of the first functional film according to the constituent materials constituting the first functional film are evaluated.

Performing the evaluation of the first functional film in the same manner as described above in the fabrication and evaluation of a blank mask having an extremely ultraviolet lithography comprising a first functional film formed with boron oxynitride (SiBON), And forming two layers of the first functional film as a functional film by injecting a process gas at a flow ratio of Ar:N ₂ :NO=6 to 10 sccm:4 to 6 sccm:0 to 4 sccm and applying a process power of 0.6 to 1.0 kW .

The evaluation results obtained by comparing the thickness of the first functional film according to the constituent materials and the composition and the etching selectivity are listed in Table 2 below.

As listed in Table 2, it can be seen that all of the first functional films prepared in the examples have an etch selectivity of 20 or more with respect to the absorbing film and 3 nm to 4 nm. The thickness, and therefore effectively, acts as an etch mask. The results obtained by measuring the flatness of each functional film by using an ultra-flat system revealed that the functional film has a total indication reading value of 75 nm to 80 nm, which indicates that the functional film is not severely affected by the film. Stress effects.

Fabrication and evaluation of blank masks for extreme ultraviolet lithography with a second functional film as an etch mask and an anti-reflective layer

In the manufacture of a blank mask for extreme ultraviolet lithography according to the present invention, a blank mask for extreme ultraviolet lithography having a second functional film as an etching mask and an antireflection layer was fabricated and evaluated.

A transparent substrate, a multilayer reflective film, and the like are prepared in the same manner as described above in the fabrication and evaluation of a blank mask having an extremely ultraviolet lithography including a first functional film formed with boron oxynitride (SiBON). The cover film is formed, and an absorbing layer other than the uppermost anti-reflective layer of the absorbing film is formed.

The absorbing film was measured using a DC magnetron reactive sputtering system, and the absorbing film was formed from a nickel (Ni) target. Further, an absorption layer was formed as a nickel nitride (NiN) layer having a thickness of 35 nm by injecting a process gas at a flow rate ratio of Ar:N ₂ =8 sccm:2 sccm and applying a treatment power of 1.0 kW.

Next, a DC magnetron reactive sputtering system is used to form a second functional film on the absorbing film. The second functional film is formed as a functional film by injecting a process gas at a flow ratio of Ar:N ₂ :NO=6 to 10 sccm:4 to 6 sccm:0 to 4 sccm and applying a process power of 0.6 kW to 1.0 kW.

The evaluation results of the reflectance at each wavelength according to the constituent materials, component ratios, and thicknesses of the second functional film are listed in Table 3 below.

table 3

As listed in Table 3, it is revealed that the second functional film has a reflectance of 1.0% to 1.2% and 18.5% to 21.0% at the exposure wavelength (13.5 nm) and the detection wavelength (193 nm), respectively. It is indicated that the optical properties of the second functional film are similar to those of the above-described absorbing film formed with the antireflection layer.

Therefore, an excellent evaluation result was confirmed because the etching selectivity to the absorption film was maintained while maintaining optical properties.

Manufacture and evaluation of blank masks for extreme ultraviolet lithography using a third functional film as an etch mask

In the manufacture of a blank mask for extreme ultraviolet lithography according to the present invention, a second functional film having an etch mask and an anti-reflective layer to pattern the absorbing layer is fabricated and evaluated and used as an etch mask to pattern the second The extreme ultraviolet lithography of the third functional film of the functional film is covered with a blank mask.

Forming a second functional film in the same manner as described above in the examples, and forming a third functional film using a DC magnetron reactive sputtering system, and the third functional film is targeted by chromium (Cr) form. Next, the third functional film was formed to have a thickness of 4 nm by injecting a process gas at a rate of Ar = 8 sccm and applying a processing power of 0.7 kW. Thereafter, the third functional film was subjected to surface treatment at 350 ° C for 20 minutes in a vacuum rapid thermal processing system to form a chemically amplified resist film having a thickness of 80 nm.

Next, a 50 keV writing machine was used to expose the manufactured extreme ultraviolet lithography to light with a blank mask, and a pattern was formed on the resist film via post exposure bake (PEB) and development. Thereafter, the third functional film formed of chromium (Cr) was etched through the pattern of the resist film using a chlorine (Cl) etching gas for 150 seconds (in the case of considering excessive etching). In this case, the thickness of the residual resist film was measured. As a result, it was revealed that the residual resist film had a thickness of 23 nm, and thus was effectively used as an etching mask. Subsequently, the residual resist film is removed, and the second functional film is etched using an etching gas via a patterned third functional film serving as an etching mask, the etching gas containing SF ₆ gas which is a fluorine (F)-based gas . Further, an absorbing gas formed of nickel nitride (NiN) is etched using an etching gas containing chlorine (Cl). In this case, the third functional film formed of chromium (Cr) is also removed to form the final pattern of the absorbing film.

The resolution of the reticle for extreme ultraviolet lithography according to the present invention was measured using a critical dimension scanning electron microscopy. The results revealed that the same spatial pattern was defined as a depth of 40 nm. Next, the critical dimension linearity of the reticle for the extreme ultraviolet lithography was measured in the range of 60 nm to 1,000 nm. As a result, it was revealed that the extreme ultraviolet lithography mask has a high critical dimension linear value of 1.8 nm, 2.5 nm, and 2.8 nm in the same line pattern, line and space pattern, and the same space pattern, respectively.

According to the present invention, by adjusting the composition ratio between the metal constituting the absorbing film and the light element, the desired optical properties of the absorbing film can be ensured and the thinning of the absorbing film can also be achieved. Furthermore, according to the present invention, since a functional film having different etching properties compared to the absorbing film can also be used as an etching mask for etching the absorbing film to achieve thinning of the resist film, high-quality extreme ultraviolet lithography Use a reticle to form a sub-resolution feature size (SRFS) of 14 nm or less (especially 10 nm or less) The pattern of 10 nm) shows excellent pattern accuracy.

It will be apparent to those skilled in the art that various modifications of the above-described exemplary embodiments of the invention can be made without departing from the scope of the invention. Accordingly, the present invention is intended to cover all such modifications, and the scope of the appended claims

300‧‧‧Very UV lithography with blank mask

302‧‧‧Transparent substrate

304‧‧‧Multilayer Reflective Film

306‧‧‧ Cover film

308‧‧‧Absorbent layer

310‧‧‧Anti-reflective layer

312‧‧‧Absorbing film

318‧‧‧resist film

Claims (18)

A blank mask for extreme ultraviolet lithography, comprising a multilayer reflective film, a cover film, an absorption film and a resist film which are sequentially stacked on a transparent substrate, wherein the absorption film comprises nickel (Ni) and nickel ruthenium ( At least one of NiTa) and at least one light element selected from the group consisting of oxygen (O), nitrogen (N), carbon (C), and boron (B), and the light element is opposite to the nickel (Ni Or the composition ratio of the nickel lanthanum (NiTa) is in the range of 99 atom%: 1 atom% to 20 atom%: 80 atom%. A blank mask for extreme ultraviolet lithography, comprising a reflective film, a cover film, an absorption film, a first functional film and a resist film which are sequentially stacked on a transparent substrate, wherein the absorption film comprises nickel (Ni) And at least one of nickel lanthanum (NiTa) and at least one light element selected from the group consisting of oxygen (O), nitrogen (N), carbon (C), and boron (B), said light element A composition ratio of nickel (Ni) or the nickel lanthanum (NiTa) is in a range of 99 at%: 1 at% to 20 at%: 80 at%, and the first functional film is used as a pattern for patterning An etch mask for the absorbing film. The blank mask for extreme ultraviolet lithography according to claim 2, wherein the first functional film comprises a layer selected from the group consisting of chromium (Cr), tantalum (Ta), molybdenum (Mo), and bismuth (Si). At least one material of the group, or in addition to the material, at least one light selected from the group consisting of oxygen (O), nitrogen (N), carbon (C), boron (B), and hydrogen (H) An element, and the composition ratio of the light element to the material is in the range of 100 atom%: 0 atom% to 20 atom%: 80 atom%. The blank mask for extreme ultraviolet lithography according to claim 2, wherein the first functional film has a thickness of from 1 nm to 10 nm. A blank mask for extreme ultraviolet lithography, comprising a reflective film sequentially stacked on a transparent substrate, a cover film, an absorption film including an absorption layer and a second functional film, and a resist film, wherein the absorption layer At least one of nickel (Ni) and nickel lanthanum (NiTa) and at least one light element selected from the group consisting of oxygen (O), nitrogen (N), carbon (C), and boron (B), The composition ratio of the light element to the nickel (Ni) or the nickel lanthanum (NiTa) is in the range of 99 atom%: 1 atom% to 20 atom%: 80 atom%, and the second functional film acts as a An etch mask configured to pattern the absorbing layer and as an anti-reflective layer when the second functional film remains on the absorbing layer. The blank mask for extreme ultraviolet lithography according to claim 5, wherein the absorbing film and the second functional film have a stack thickness of 30 nm to 70 nm. A blank mask for extreme ultraviolet lithography, comprising a reflective film, a cover film, an absorbing film comprising an absorbing layer and a second functional film, a third functional film, and a resist film, which are sequentially stacked on a transparent substrate, Wherein the absorption layer comprises at least one of nickel (Ni) and nickel lanthanum (NiTa) and at least one selected from the group consisting of oxygen (O), nitrogen (N), carbon (C), and boron (B) a light element having a composition ratio of the nickel (Ni) or the nickel niobium (NiTa) in a range of 99 atom%: 1 atom% to 20 atom%: 80 atom%, the second The functional film acts as an etch mask configured to pattern the absorbing layer and as an anti-reflective layer when the second functional film remains on the absorbing layer, and The third functional film acts as an etch mask configured to pattern the second functional film. A blank mask for extreme ultraviolet lithography as described in claim 5 or 7, wherein the nickel iridium (NiTa) target is used when the absorbing layer is formed to include the nickel lanthanum (NiTa) The composition ratio is in the range of Ni:Ta = 5 at% to 95 at%: 95 at% to 5 at%. The blank mask for extreme ultraviolet lithography according to claim 5 or 7, wherein the second functional film comprises a layer selected from the group consisting of chromium (Cr), tantalum (Ta), molybdenum (Mo), and tantalum ( At least one material of the group consisting of, or comprising, in addition to the material, a group selected from the group consisting of oxygen (O), nitrogen (N), carbon (C), boron (B), and hydrogen (H) At least one light element, and the composition ratio of the light element to the material is in the range of 100 atom%: 0 atom% to 20 atom%: 80 atom%. The blank mask for extreme ultraviolet lithography according to claim 7, wherein the third functional film has a thickness of from 1 nm to 10 nm. The blank mask for extreme ultraviolet lithography according to claim 5 or 7, wherein the second functional film has a thickness of 5 nm to 20 nm. The blank mask for extreme ultraviolet lithography according to any one of claims 1, 2, 5, and 7, wherein the absorbing film has less than 10% with respect to extreme ultraviolet exposure light having a wavelength of 13.5 nm. Reflectivity. The blank mask for extreme ultraviolet lithography according to any one of claims 1, 2, 5, and 7, wherein the absorbing film has a reflectance of less than 30% at a detection wavelength of 193 nm. The blank mask for extreme ultraviolet lithography according to claim 7, wherein the third functional film comprises chromium (Cr), or in addition to the chromium (Cr) Further comprising at least one light element selected from the group consisting of oxygen (O), nitrogen (N), carbon (C), boron (B), and hydrogen (H), and the composition of the light element to the chromium The ratio is in the range of 100 atom%: 0 atom% to 20 atom%: 80 atom%. The blank mask for extreme ultraviolet lithography according to any one of claims 1, 2, 5, and 7, further comprising a buffer film disposed between the cover film and the absorbing film. The blank mask for extreme ultraviolet lithography according to any one of claims 1, 2, 5 and 7, further comprising a conductive film provided in a rear surface of the transparent substrate. The blank mask for extreme ultraviolet lithography according to any one of claims 1, 2, 5, and 7, further comprising: disposed on the resist film and disposed under the resist film A bismuth-containing polymer compound between the membranes. A reticle is obtained by forming a pattern on a blank mask for extreme ultraviolet lithography as described in any one of claims 1, 2, 5 and 7.