Raw mask and photomask

Abstract

Raw mask (100), comprising: a translucent substrate (10); and a multilayer (20) arranged on the translucent substrate (10), wherein the multilayer (20) comprises a light-shielding layer (22) arranged on the translucent substrate (10) and a phase-shifting layer (21) arranged between the translucent substrate (10) and the light-shielding layer (22), and comprising an upper surface (21f) facing the light-shielding layer (22) and a side surface (21s) connected to the upper surface, the light-shielding layer (22) being arranged to cover the upper surface (21f) and the side surface (21s) of the phase-shifting layer (21), viewed from the upper surface of the multilayer (20), the multilayer (20) comprising a middle section (201) and an outer section (202) surrounding the middle section (201),and the outer section (202) has a curved upper surface, wherein: the translucent substrate (10) comprises an upper surface facing the phase-shift layer (21); and the light-shielding layer (22) is arranged to cover at least a section of the upper surface of the translucent substrate (10), and wherein: the translucent substrate (10) further comprises a side surface connected to the upper surface of the translucent substrate (10); the side surface of the translucent substrate (10) comprises a first surface (s1) curved to extend from the upper surface of the translucent substrate (10), and a second surface (s2) extending from the first surface in a vertical direction to the raw mask (100); and the light-shielding layer (22) is arrangedthat it covers at least one section of the first surface (s1) of the translucent substrate (10).

Description

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of priority from Korean Patent Application No. 10-2022-0103470, filed on August 18, 2022. 1. Area

[0002] Embodiments of the present invention relate to a blank mask and a photomask therewith. 2. Discussion of the state of the art

[0003] Due to the high integration of semiconductor devices, fineness in circuit patterns is required. Therefore, the importance of lithography, a technique for developing circuit patterns on wafer surfaces using photomasks, is increasing.

[0004] To develop fine circuit patterns, short wavelengths of exposure light sources are required for exposure processes. Recently, an ArF excimer laser (with a wavelength of 193 nm) has been used as an exposure light source.

[0005] Meanwhile, the photomask includes a binary mask and a phase shift mask.

[0006] The binary mask has a configuration in which a light-shielding layer pattern is formed on a light-transmitting substrate. On a surface of the binary mask where a pattern is formed, a transmitting portion not including a light-shielding layer transmits exposure light, and a blocking portion including the light-shielding layer blocks the exposure light, so that the pattern is developed in a resist film on a wafer surface. However, as the pattern becomes finer, the binary mask may have a problem developing a fine pattern due to the diffraction of light generated by an edge of the transmitting portion during the exposure process.

[0007] Phase shift masks include Levenson phase shift masks, outrigger phase shift masks, and halftone phase shift masks. Among the phase shift masks, the halftone phase shift mask has a configuration in which a pattern of a semi-transparent layer is formed on a light-transmitting substrate. On a surface of the halftone phase shift mask on which a pattern is formed, a transmissive portion not including a semi-transmissive layer transmits exposure light, and a semi-transmissive portion including the semi-transmissive layer transmits attenuated exposure light. The attenuated exposure light has a phase difference compared to the exposure light passing through the transmissive portion.Thus, since diffracted light generated by an edge of the transmissive portion is offset by the exposure light passing through the semi-transmissive portion, the phase shift mask can form a more elaborate fine pattern on the surface of the wafer. SUMMARY

[0008] The present invention is directed to providing a mask blank that substantially prevents damage to a phase shift layer by a cleaning solution and effectively reduces a frequency of generation of particles originating from the phase shift layer and a light-shielding layer.

[0009] According to one aspect of the present invention, a mask blank is provided comprising a light-transmissive substrate and a multilayer disposed on the light-transmissive substrate.

[0010] The multilayer may include a light-shielding layer disposed on the light-transmitting substrate, and a phase shift layer disposed between the light-transmitting substrate and the light-shielding layer, and including an upper surface facing the light-shielding layer and a side surface connected to the upper surface.

[0011] The light-shielding layer may be arranged to cover the top surface and a side surface of the phase shift layer.

[0012] When viewed from the top surface of the multilayer, the multilayer may include a central portion and an outer portion surrounding the central portion.

[0013] The outer portion may have a curved upper surface.

[0014] The light-transmissive substrate may include an upper surface facing the phase shift layer.

[0015] The light-shielding layer may be arranged to cover at least a portion of the upper surface of the light-transmitting substrate.

[0016] The light-transmissive substrate may further comprise a side surface connected to the top surface of the light-transmissive substrate.

[0017] The side surface of the light-transmitting substrate may include a first surface curved to extend from the top surface of the light-transmitting substrate and a second surface extending from the first surface in a vertical direction of the mask blank.

[0018] The light-shielding layer may be arranged to cover at least a portion of the first surface of the light-transmitting substrate.

[0019] Viewed from the top surface of the multilayer, a region A of the light-transmitting substrate, a region B of the light-shielding layer, and a region C of the phase shift layer can satisfy the following equation 1. A≥B>C

[0020] The outer portion of the multilayer may include a slope region in which a thickness of the multilayer continuously increases from an edge of the multilayer in an inward direction of the multilayer.

[0021] The inclination region may be located in the outermost section of the multilayer.

[0022] Viewed from a cross-section of the multilayer, the slope region may have a width in the range of 0.2 mm to 1.0 mm in one direction in the plane of the multilayer.

[0023] Among dT values ​​according to equation 2, measured from the multilayer, a maximum value can be in the range of 10 nm to 30 nm. dT=T1−T2

[0024] In equation 2, T1 may denote a thickness of the multilayer measured at a first point located in the multilayer.

[0025] T2 may denote a thickness of the multilayer measured at a second point located 0.1 mm away from the first point in a direction of an edge of the multilayer.

[0026] Among ddT values ​​according to equation 3, measured from the multilayer, a maximum value may be 30 nm or less. ddT=|(T1−T2)−(T2−T3)|

[0027] In equation 3, T1 may denote a thickness of the multilayer measured at a first point located in the multilayer.

[0028] T2 may denote a thickness of the multilayer measured at a second point located 0.1 mm away from the first point in a direction of an edge of the multilayer.

[0029] T3 may denote a thickness of the multilayer measured at a third point located 0.1 mm from the second point in the direction of one edge of the multilayer.

[0030] The multilayer may include a lower surface facing the light-transmissive substrate.

[0031] The phase shift layer may include a lower surface facing the light-transmitting substrate.

[0032] Viewed from the cross-section, the lower surface (lower boundary) of the multilayer may include a first edge, which is one end, and a second edge, which is the other end positioned opposite the first edge.

[0033] Viewed from the cross-section, the lower surface (lower boundary) of the phase shift layer may include a third edge, which is one end positioned adjacent to the first edge, and a fourth edge, which is the other end positioned adjacent to the second edge.

[0034] The smaller value of a distance value between the first edge and the third edge and a distance value between the second edge and the fourth edge may be 0.1 nm or more.

[0035] A photomask according to another embodiment of the present invention can be manufactured from the blank mask.

[0036] According to another aspect of the present invention, there is provided a method for manufacturing a semiconductor device, comprising a preparation process of arranging a light source, a photomask, and a semiconductor wafer on which a resist layer is applied, an exposure process of selectively transmitting and emitting light incident from the light source through the photomask onto the semiconductor wafer, and a development process of developing a pattern on the semiconductor wafer.

[0037] The photomask can be made from the raw mask. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The above and other objects, features and advantages of the present invention will become more apparent to those skilled in the art by describing exemplary embodiments thereof in detail with reference to the accompanying drawings, in which: Fig.1 is a plan view illustrating a mask blank according to an embodiment of the present invention; Fig. 2a, Fig. 2b and Fig. 2c are conceptual representations for describing an outer portion of a multilayer; Fig. 3a is a conceptual representation for describing an edge of a lower surface of the multilayer and Fig. 3b is a partially enlarged view showing the outer portion of the multilayer of Fig. 3a illustrates; Fig. 4 is a conceptual diagram for describing a blank mask according to another embodiment of the present invention; Fig. 5 is a conceptual diagram for describing a mask blank according to still another embodiment of the present invention; and Fig.6 is a diagram showing surface profiles of a light-shielding layer of Example 1 and a multilayer of Example 2. DETAILED DESCRIPTION

[0039] In the following, embodiments are described in detail so that those skilled in the art to which the present invention relates can easily practice the embodiments. However, the embodiments can be implemented in various forms and are not limited to the embodiments described herein.

[0040] As used herein, the terms "about," "substantially," and the like are used to mean at or near the numerical value when representing manufacturing and material tolerances inherent in the stated meaning, and to aid in the understanding of embodiments and prevent unscrupulous infringers from taking undue advantage of this disclosure in which exact or absolute numerical values ​​are stated.

[0041] Throughout this specification, the term "a combination thereof" included in a Markush form expression means a mixture or combination of one or more selected from the group consisting of components described in the Markush form expression and means to include one or more selected from the group consisting of the above components.

[0042] Throughout this specification, the description of “A and / or B” means “A or B or A and B.”

[0043] Throughout this specification, terms such as “first”, “second”, “A” and “B” are used to distinguish the same terms from one another unless otherwise specified.

[0044] In the present description, the meaning that B is positioned on A means that B is positioned on A or B is positioned or is to be positioned on A with another layer interposed therebetween, and is not interpreted as being limited to B being positioned in contact with a surface of A.

[0045] In this specification, a singular form is construed to have a meaning that includes the singular form or a plural form as interpreted in context, unless otherwise specified.

[0046] In this specification, “surrounding” is interpreted as meaning that includes both contacting and surrounding an object to be surrounded and surrounding an object to be surrounded without contact.

[0047] To remove contaminants remaining on a manufactured mask blank, the mask blank can be cleaned. The cleaning solution applied in the mask blank cleaning process often uses a solution with relatively high chemical reactivity. Among the thin film layers contained in the mask blank, a phase shift layer has relatively poor chemical resistance compared to other thin film layers. In particular, one side surface of the phase shift layer is directly exposed to the cleaning solution during the cleaning process and is easily damaged during the cleaning process.

[0048] Furthermore, a problem is that particles are continuously generated in the cleaned mask blank over time. This is believed to be due to particles originating from the phase shift layer damaged by the cleaning solution being generated during storage and movement of the mask blank, or to the formation of numerous particles when the light-shielding layer is damaged due to impact or oxidation. In particular, corners of the light-shielding layer are considered to be vulnerable to external impact.

[0049] The inventors of embodiments have experimentally confirmed that the phase shift layer can be stably protected from the cleaning solution and the formation of particles originating from the phase shift layer and the light-shielding layer can be effectively prevented by applying a structure covering an upper surface and a side surface of the phase shift layer to the light-shielding layer and allowing an outer portion of the light-shielding layer to have a curved upper surface, thereby completing the embodiments.

[0050] In the following, the embodiments of the present invention will be described in detail. Shape and structure of the multilayer

[0051] Fig. 1 is a plan view for describing a mask blank according to an embodiment of the present invention. Fig. 2a, Fig. 2b and Fig.2c are conceptual diagrams for describing an outer portion of a multilayer. The blank mask of the embodiment will be described with reference to Fig. 1, Fig. 2a, Fig. 2b and Fig. 2c described.

[0052] A blank mask 100 includes a light-transmitting substrate 10 and a multilayer 20 disposed on the light-transmitting substrate 10.

[0053] A material of the light-transmitting substrate 10 is not limited as long as it has light transmittance to exposure light and is applicable to the mask blank 100. Specifically, the transmittance of the light-transmitting substrate 10 to exposure light having a wavelength of 193 nm may be 85% or more. The transmittance may be 87% or more. The transmittance may be 99.99% or less. For example, a synthetic quartz substrate may be applied as the light-transmitting substrate 10. In this case, the light-transmitting substrate 10 can suppress attenuation of light passing through the light-transmitting substrate 10.

[0054] In addition, the occurrence of optical distortion can be suppressed by adjusting surface properties, such as flatness and roughness, of the light-transmitting substrate 10.

[0055] The multilayer 20 includes a light-shielding layer 22 disposed on the light-transmitting substrate 10, and a phase shift layer 21 disposed between the light-transmitting substrate 10 and the light-shielding layer 22, and including an upper surface facing the light-shielding layer 22 and a side surface connected to the upper surface.

[0056] The phase shift layer 21 has a function of attenuating a light intensity of exposure light passing through the phase shift layer 21. In this way, it is possible to substantially suppress diffracted light generated at an edge of a transfer pattern by adjusting a phase difference of the exposure light.

[0057] The light-shielding layer 22 may be positioned on an upper surface (top side) of the light-transmissive substrate 10. The light-shielding layer 22 may have a property of blocking at least a portion of the exposure light incident on a lower surface (bottom side) of the light-transmissive substrate 10. Furthermore, the light-shielding layer 22 may be used as an etching mask in a process for patterning the phase-shifting layer 21.

[0058] The light-shielding layer 22 is arranged to cover an upper surface 21f and a side surface 21s of the phase shift layer 21. The light-shielding layer 22 may be arranged in contact with the upper surface 21f of the phase shift layer 21. The light-shielding layer 22 may be arranged in contact with the side surface 21s of the phase shift layer 21. If another thin film (not shown) is positioned between the light-shielding layer 22 and the phase shift layer 21, the light-shielding layer 22 may be arranged without contact with the upper surface 21f and the side surface 21s of the phase shift layer 21. The light-shielding layer having the above structure can stably protect the phase shift layer 21 from the cleaning solution in the cleaning process.

[0059] Viewed from the top of the multilayer 20, the multilayer 20 comprises a central portion 201 and an outer portion 202 surrounding the central portion 201.

[0060] The central portion 201 is positioned at the center of the multilayer 20 and has a relatively uniform thickness distribution. The central portion 201 having the relatively uniform thickness distribution means that an absolute value of a dT value measured at each point in the central portion 201 according to the following equation 2 is 8 nm or less. dT=T1−T2

[0061] In equation 2, T1 denotes a thickness of the multilayer 20 measured at a first point located on top of the multilayer 20.

[0062] T2 denotes a thickness of the multilayer 20 measured at a second point located 0.1 mm away from the first point in a direction of an edge of the multilayer 20.

[0063] One edge of the multilayer is closest to the first point among the edges of the multilayer.

[0064] The T1 and T2 values ​​are measured using a surface profilometer. As an example, the T1 and T2 values ​​can be measured using a surface profilometer by setting a stylus radius to 12.5 µm and a force to 3.00 mg and applying a Hills & Valleys measurement method.

[0065] The T1 value and the T2 value may be measured from the measured target blank mask 100 itself or may be measured from a sample formed by cutting the blank mask 100.

[0066] If the light-transmitting substrate 10 of the blank mask 100 to be measured includes a chamfer on one edge (see Fig. 4), a portion of the multilayer 20 formed on a surface of the chamfer is excluded from a measurement target.

[0067] As an example, a Dektak 150 model from Veeco Instruments Inc. can be applied as the surface profilometer.

[0068] The outer portion 202 may be a region excluding the middle portion 201 in the multilayer 20.

[0069] The outer portion 202 has a curved upper surface. The outer portion 202 having a curved upper surface means that the thickness of the multilayer 20 in at least a portion of the outer portion 202 is continuously varied in one direction in the plane of the multilayer 20 (see Fig. 2a to Fig. 2c).

[0070] When the curved upper surface is applied to the outer portion of the multilayer and when an external force is applied to the multilayer during storage or movement of the mask blank, damage to the multilayer due to excessive concentration of the external force on a specific portion within the multilayer can be substantially prevented.

[0071] The light-transmitting substrate 10 may include an upper surface facing the phase shift layer 21. The light-shielding layer 22 may be arranged to cover at least a portion of the upper surface of the light-transmitting substrate 10. In particular, the light-shielding layer 22 may cover all or part of an area where the phase shift layer 21 is not located on the upper surface of the light-transmitting substrate 10. In this case, the multilayer may have a structure in which a side surface of the phase shift layer is not exposed to the outside.

[0072] Viewed from the upper surface of the multilayer 20, a region A of the light-transmitting substrate 10, a region B of the light-shielding layer 22, and a region C of the phase shift layer 21 can satisfy the following equation 1. A≥B>C

[0073] When the above equation 1 is satisfied, the phase shift layer which has poor cleaning resistance in the cleaning process can be stably protected from the cleaning solution.

[0074] Fig. 3a is a conceptual diagram for describing an edge of a bottom surface of the multilayer and Fig. Figure 3b is a partially enlarged view showing the outer portion of the multilayer of Fig. 3a. In the following, a blank mask of an embodiment is described with reference to Fig. 3a and Fig. 3b.

[0075] The outer portion 202 of the multilayer 20 may include a slope region SA in which the thickness of the multilayer 20 continuously increases from the edge of the multilayer 20 in an inward direction of the multilayer 20. In the slope region SA, the thickness of the multilayer 20 may increase irregularly and continuously from the edge of the multilayer 20 in the inward direction of the multilayer 20.

[0076] The sloped region SA may be formed in at least a partial region of the outer portion 202 of the multilayer 20. The sloped region SA may be formed in the entire region of the outer portion 202 of the multilayer 20. The outer portion 202 of the multilayer 20 may include one sloped region SA or a plurality of sloped regions SA.

[0077] The sloped region SA may be located in the outermost portion of the multilayer 20. Viewed from a cross section of the multilayer 20, the sloped region SA may have a width W in the range of 0.2 mm to 1.0 mm in the in-plane direction of the multilayer 20. The width W may be 0.3 mm or more. The width W may be 0.8 mm or less. This may contribute to the side surface of the multilayer having a suitable slope to improve the impact resistance of the multilayer.

[0078] As an example, the width W of the slope region SA observed from the cross section of the multilayer 20 in the in-plane direction can be measured by a surface profilometer. A method for measuring the width by the surface profilometer overlaps the content described above and is therefore omitted.

[0079] The phase shift layer 21 may include a lower surface facing the light-transmitting substrate 10.

[0080] The multilayer 20 may include a lower surface facing the light-transmissive substrate 10.

[0081] The lower surface of the multilayer 20 may be a horizontally extending surface of the lower surface of the phase shift layer 21. In this case, the lower surface of the multilayer 20 may include the lower surface of the phase shift layer 21.

[0082] Viewed from the cross-section, the lower surface (lower boundary) of the multilayer 20 may include a first edge e1, which is one end, and a second edge e2, which is the other end positioned opposite the first edge e1. The lower surface (lower boundary) of the phase shift layer 21 may include a third edge e3, which is one end positioned adjacent to the first edge e1, and a fourth edge e4, which is the other end positioned adjacent to the second edge e2. The first edge e1 and the third edge e3 may be parallel, and the second edge e2 and the fourth edge e4 may be parallel, but the present invention is not limited thereto.

[0083] The smaller value of a distance value between the first edge e1 and the third edge e3 and a distance value between the second edge e2 and the fourth edge e4 may be 0.1 nm or more. The smaller value may be 0.3 nm or more. The smaller value may be 0.5 nm or more. The smaller value may be 1 nm or more. The smaller value may be 1.5 nm or more. The smaller value may be 5 nm or less. The smaller value may be 3 nm or less.

[0084] In these cases, chemical damage to the side surface of the phase shift layer can be effectively prevented according to the cleaning process.

[0085] A distance value between edges observed from the cross section of the multilayer 20 is measured using a surface profilometer. Specifically, a surface profile of the multilayer 20 is measured using the surface profilometer, and the light-shielding layer 22 of the multilayer 20 is etched and removed. Thereafter, the distance value between the edges is calculated by measuring the surface profile of the phase-shifting layer 21.

[0086] As an example, surface profiles of the multilayer and phase shift layers can be measured by setting a pin radius to 12.5 µm and a force to 3.00 mg and applying a Hills & Valleys measurement method.

[0087] Among the dT values ​​according to equation 2, measured from the multilayer 20, a maximum value may be in the range of 10 nm to 30 nm.

[0088] According to the embodiment, the maximum value of the dT value measured from the multilayer 20 can be controlled within a range preset in the embodiment. Thus, the durability of the multilayer can be further improved by reducing the angular position of the upper surface of the multilayer, and the side surface of the phase shift layer can be stably protected on a substrate with a limited area.

[0089] The maximum dT value measured from the multilayer 20 can be in the range of 10 nm to 30 nm. The maximum value can be 12 nm or more. The maximum value can be 14 nm or more. The maximum value can be 28 nm or less. The maximum value can be 26 nm or less. The maximum value can be 24 nm or less. In these cases, the phase shift layer can be effectively protected from the cleaning fluid, and the durability of the multilayer can be further improved.

[0090] A maximum value among ddT values ​​measured from the multilayer 20 according to the following equation 3 may be 25 nm or less. ddT=|(T1−T2)−(T2−T3)|

[0091] In equation 3, T1 denotes a thickness of the multilayer 20 measured at a first point located in the multilayer 20.

[0092] T2 denotes a thickness of the multilayer 20 measured at a second point located 0.1 mm away from the first point in a direction of an edge of the multilayer 20.

[0093] T3 denotes a thickness of the multilayer 20 measured at a third point located 0.1 mm away from the second point in a direction of an edge of the multilayer 20.

[0094] According to the embodiment, the maximum value among the ddT values ​​measured from the multilayer 20 can be controlled within a range preset in the embodiment. Thus, the upper surface of the multilayer 20 has a relatively smooth shape, so that the frequency of particle generation due to damage to the multilayer 20 can be effectively reduced.

[0095] The ddT value according to Equation 3 is calculated from the T1 value, the T2 value, and the T3 value. The T1 value, the T2 value, and the T3 value are measured by a surface profilometer. A method for measuring the T1 value, the T2 value, and the T3 value overlaps those described above and is therefore omitted.

[0096] A maximum value among the ddT values ​​measured from the multilayer 20 according to Equation 3 may be 30 nm or less. The maximum value may be 28 nm or less. The maximum value may be 25 nm or less. The maximum value may be 22 nm or less. The maximum value may be 1 nm or more. The maximum value may be 5 nm or more. The maximum value may be 10 nm or more. In these cases, the impact resistance of the multilayer 20 can be further improved.

[0097] Fig.Fig. 4 is a conceptual diagram for describing a mask blank according to another embodiment of the present invention. Hereinafter, the mask blank of this embodiment will be described with reference to Fig. 4 described.

[0098] A light-transmissive substrate 10 may further include a side surface connected to a top surface of the light-transmissive substrate 10.

[0099] The side surface of the light-transmitting substrate 10 may include a first surface s1 curved to extend from the upper surface of the light-transmitting substrate 10 and a second surface s2 extending from the first surface s1 in a vertical direction of a mask blank 100.

[0100] A light-shielding layer 22 may be provided to cover at least a portion of the first surface s1 of the light-transmitting substrate 10.

[0101] When the first surface s1 and the second surface s2 are applied to the side surface of the light-transmitting substrate 10 at the same time, damage to the edge due to impact can be prevented.

[0102] In this embodiment, a structure can be applied in which the light-shielding layer 22 covers at least a portion of the first surface s1 of the light-transmitting substrate 10. In this way, the light-shielding layer can more stably protect a side surface of a phase shift layer.

[0103] Fig. Fig. 5 is a conceptual diagram for describing a mask blank according to yet another embodiment of the present invention. Hereinafter, the mask blank of this embodiment will be described with reference to Fig. 5 described.

[0104] A light-shielding layer 22 may include a first light-shielding layer 221 and a second light-shielding layer 222 disposed on the first light-shielding layer 221. Thickness of the multilayer

[0105] A thickness of a central portion 201 of a multilayer 20 may be 80 nm or more. The thickness may be 90 nm or more. The thickness may be 100 nm or more. The thickness may be 110 nm or more. The thickness may be 160 nm or less. The thickness may be 150 nm or less. The thickness may be 140 nm or less. The thickness may be 130 nm or less. In these cases, the multilayer 20 may substantially suppress transmission of exposure light.

[0106] A minimum value of a thickness of an outer portion 202 of the multilayer 20 may be 0.1 nm or more. The minimum value may be 0.3 nm or more. The minimum value may be 0.5 nm or more. The minimum value may be 5 nm or less. The minimum value may be 3 nm or less.

[0107] A thickness of the multilayer 20, measured at an edge of the multilayer 20, may be 0.1 nm or more. The thickness may be 0.3 nm or more. The thickness may be 0.5 nm or more. The thickness may be 5 nm or less. The thickness may be 3 nm or less.

[0108] A thickness of the light-shielding layer 22, measured at the edge of the light-shielding layer 22, may be 0.1 nm or more. The thickness may be 0.3 nm or more. The thickness may be 0.5 nm or more. The thickness may be 5 nm or less. The thickness may be 3 nm or less.

[0109] In these cases, the durability of a side surface and a corner of the multilayer can be further improved.

[0110] The thickness of the multilayer 20 and the thickness of the light-shielding layer 22 at the edge of the light-shielding layer 22 are measured by a surface profilometer. A method for measuring the thickness overlaps the above-described content and is therefore omitted.

[0111] The thickness of the light-shielding layer 22 may be in the range of 280 Å to 850 Å. The thickness may be in the range of 380 Å to 700 Å. The thickness may be in the range of 440 Å to 630 Å. In these cases, the light-shielding layer may exhibit stable light extinction properties.

[0112] A thickness of the first light-shielding layer 221 may be in the range of 250 Å to 650 Å. The thickness of the first light-shielding layer 221 may be in the range of 350 Å to 600 Å. The thickness of the first light-shielding layer 221 may be in the range of 400 Å to 550 Å.

[0113] A thickness of the second light-shielding layer 222 may be in the range of 30 Å to 200 Å. The thickness of the second light-shielding layer 222 may be in the range of 30 Å to 100 Å. The thickness of the second light-shielding layer 222 may be in the range of 40 Å to 80 Å.

[0114] In these cases, the light-shielding layer 22 can have an excellent light extinction property and a more complex light-shielding pattern layer can be formed.

[0115] The ratio of the thickness of the second light-shielding layer 222 to the thickness of the first light-shielding layer 221 may be in the range of 0.05 to 0.3. The thickness ratio may be in the range of 0.07 to 0.25. The thickness ratio may be in the range of 0.1 to 0.2. In these cases, the shape of a side surface of the light-shielding pattern layer formed by patterning can be more precisely controlled.

[0116] The thickness of the light-shielding layer 22 and the thickness of each layer included in the light-shielding layer 22 are measured by transmission electron microscopy (TEM). The thickness of the light-shielding layer 22 and the thickness of each layer included in the light-shielding layer 22 are measured in areas corresponding to the central portion 201 of the multilayer 20.

[0117] A thickness of the phase shift layer 21 may be 40 nm or more. The thickness may be 50 nm or more. The thickness may be 60 nm or more. The thickness may be 100 nm or less. The thickness may be 90 nm or less. The thickness may be 80 nm or less. In these cases, the phase shift layer may have a phase shift property sufficient to offset diffracted light.

[0118] The thickness of the phase-shift layer 21 is measured by TEM. The thickness of the phase-shift layer 21 is measured in a region corresponding to the central portion 201 of the multilayer 20. Composition of each thin film layer in the multilayer

[0119] In this embodiment, a composition of each thin film layer in the multilayer 20 can be controlled in consideration of durability, etching properties, and the like required for the multilayer 20.

[0120] The content of each element for each thin film layer of the light layer 20 can be confirmed by measuring a depth profile using X-ray photoelectron spectroscopy (XPS). Specifically, a sample is prepared by processing the blank mask 100 into a size of 15 mm horizontally and 15 mm vertically. Afterward, the sample is placed in the XPS measurement equipment, and the content of each element for each layer is measured by etching an area of ​​4 mm horizontally and 2 mm vertically positioned in a central portion of the sample.

[0121] For example, the content of each element for each layer can be measured by a K-alpha model from Thermo Fisher Scientific Inc.

[0122] The first light-shielding layer 221 may contain 25 atomic percent or more of transition metal. The first light-shielding layer 221 may contain 30 atomic percent or more of transition metal. The first light-shielding layer 221 may contain 35 atomic percent or more of transition metal. The first light-shielding layer 221 may contain 50 atomic percent or less of transition metal. The first light-shielding layer 221 may contain 45 atomic percent or less of transition metal.

[0123] The first light-shielding layer 221 may contain 30 atomic% or more of oxygen. The first light-shielding layer 221 may contain 35 atomic% or more of oxygen. The first light-shielding layer 221 may contain 55 atomic% or less of oxygen. The first light-shielding layer 221 may contain 50 atomic% or less of oxygen. The first light-shielding layer 221 may contain 45 atomic% or less of oxygen.

[0124] The first light-shielding layer 221 may contain 2 atomic percent or more of nitrogen. The first light-shielding layer 221 may contain 5 atomic percent or more of nitrogen. The first light-shielding layer 221 may contain 8 atomic percent or more of nitrogen. The first light-shielding layer 221 may contain 25 atomic percent or less of nitrogen. The first light-shielding layer 221 may contain 20 atomic percent or less of nitrogen. The first light-shielding layer 221 may contain 15 atomic percent or less of nitrogen.

[0125] The first light-shielding layer 221 may contain 2 atomic percent or more of carbon. The first light-shielding layer 221 may contain 5 atomic percent or more of carbon. The first light-shielding layer 221 may contain 10 atomic percent or more of carbon. The first light-shielding layer 221 may contain 25 atomic percent or less of carbon. The first light-shielding layer 221 may contain 20 atomic percent or less of carbon. The first light-shielding layer 221 may contain 18 atomic percent or less of carbon.

[0126] This can contribute to the light-shielding layer 22 having excellent light extinction properties, and can contribute to the first light-shielding layer having a relatively high etching speed compared with the second light-shielding layer.

[0127] The second light-shielding layer 222 may contain 40 atomic percent or more of transition metal. The second light-shielding layer 222 may contain 45 atomic percent or more of transition metal. The second light-shielding layer 222 may contain 50 atomic percent or more of transition metal. The second light-shielding layer 222 may contain 70 atomic percent or less of transition metal. The second light-shielding layer 222 may contain 65 atomic percent or less of transition metal. The second light-shielding layer 222 may contain 62 atomic percent or less of transition metal.

[0128] The second light-shielding layer 222 may contain 5 atomic percent or more of oxygen. The second light-shielding layer 222 may contain 8 atomic percent or more of oxygen. The second light-shielding layer 222 may contain 10 atomic percent or more of oxygen. The second light-shielding layer 222 may contain 35 atomic percent or less of oxygen. The second light-shielding layer 222 may contain 30 atomic percent or less of oxygen. The second light-shielding layer 222 may contain 25 atomic percent or less of oxygen.

[0129] The second light-shielding layer 222 may contain 5 atomic percent or more of nitrogen. The second light-shielding layer 222 may contain 8 atomic percent or more of nitrogen. The second light-shielding layer 222 may contain 30 atomic percent or less of nitrogen. The second light-shielding layer 222 may contain 25 atomic percent or less of nitrogen. The second light-shielding layer 222 may contain 20 atomic percent or less of nitrogen.

[0130] The second light-shielding layer 222 may contain 1 atomic percent or more of carbon. The second light-shielding layer 222 may contain 4 atomic percent or more of carbon. The second light-shielding layer 222 may contain 25 atomic percent or less of carbon. The second light-shielding layer 222 may contain 20 atomic percent or less of carbon. The second light-shielding layer 222 may contain 16 atomic percent or less of carbon.

[0131] This can help the multilayer have improved durability and can help implement a more elaborate pattern on the light-shielding layer.

[0132] The transition metal may contain at least one of Cr, Ta, Ti, and Hf. The transition metal may be Cr.

[0133] The phase shift layer 21 may contain 1 to 10 atomic percent of transition metal. The phase shift layer 21 may contain 2 to 7 atomic percent of transition metal.

[0134] The phase shift layer 21 may contain 15 to 60 atomic percent silicon. The phase shift layer 21 may contain 25 to 50 atomic percent silicon.

[0135] The phase shift layer 21 may contain 30 to 60 atomic percent nitrogen. The phase shift layer 21 may contain 35 to 55 atomic percent nitrogen.

[0136] The phase shift layer 21 may contain 5 to 35 atomic percent oxygen. The phase shift layer 21 may contain 10 to 25 atomic percent oxygen.

[0137] In these cases, the phase shift layer 21 may have optical properties suitable for a lithography process using short-wavelength exposure light, in particular light with a wavelength of 200 nm or less.

[0138] The transition metal deposited on the phase-shift layer 21 may contain at least one of molybdenum, Ta, and zirconium. The transition metal may be molybdenum.

[0139] The phase shift layer 21 may additionally contain other elements in addition to those described above. As an example, the phase shift layer 21 may contain argon or helium. Optical properties of the multilayer

[0140] An optical density of the multilayer 20 with respect to light having a wavelength of 193 nm may be 2.5 or more. The optical density may be 2.8 or more. The optical density may be 3.0 or more. The optical density may be 5.0 or less.

[0141] An optical density of the light-shielding layer 22 with respect to light having a wavelength of 193 nm may be 1.3 or more. The optical density of the light-shielding layer 22 with respect to light having a wavelength of 193 nm may be 1.4 or more.

[0142] The transmittance of the light-shielding layer 22 with respect to light having a wavelength of 193 nm may be 2% or less. The transmittance of the light-shielding layer 22 with respect to light having a wavelength of 193 nm may be 1.9% or less.

[0143] In these cases, the light-shielding layer can help to effectively block the transmission of exposure light.

[0144] The phase difference of the phase shift layer 21 with respect to the light with a wavelength of 193 nm can range from 170° to 190°. The phase difference of the phase shift layer 21 with respect to the light with a wavelength of 193 nm can range from 175° to 185°.

[0145] The transmittance of the phase shift layer 21 with respect to light with a wavelength of 193 nm can range from 3% to 10%. The transmittance of the phase shift layer 21 with respect to light with a wavelength of 193 nm can range from 4% to 8%.

[0146] In these cases, it is possible to effectively suppress diffracted light that may occur at an edge of the pattern layer.

[0147] The optical densities, transmittance, and phase differences for the multilayer and each thin film layer included in the multilayer are measured using a spectroscopic ellipsometer. As an example, the optical densities and the like can be measured using an MG-Pro model from NanoView Co., Ltd. other thin film layers

[0148] A hard mask (not shown) may be disposed on the light-shielding layer 22. The hard mask may serve as an etching mask during etching of the pattern of the light-shielding layer 22. The hard mask may contain silicon, nitrogen, and oxygen.

[0149] A resist layer (not shown) may be positioned on the light-shielding layer 22. The resist layer may be formed in contact with the upper surface of the light-shielding layer 22. The resist layer may be formed in contact with an upper surface of another thin film layer disposed on the light-shielding layer 22.

[0150] The resist layer can form a resist pattern layer by electron beam irradiation and development. The resist pattern layer can serve as an etching mask during etching of the pattern of the light-shielding layer 22.

[0151] A positive resist can be applied as the resist layer. A negative resist can be applied as the resist layer. For example, an FEP255 model from Fuji Co., Ltd. can be used for the resist layer. Photomask, comprising:

[0152] A photomask according to yet another embodiment of the present invention may be implemented from the raw mask.

[0153] A description of the raw mask overlaps the content described above and is therefore omitted. Method for producing a blank mask

[0154] A method for manufacturing a mask blank according to an embodiment of the present disclosure includes a multilayer formation process of forming a multilayer on a light-transmitting substrate. The multilayer formation process may include a phase shift layer formation process of forming a phase shift layer on the light-transmitting substrate and a light-shielding layer formation process of forming a light-shielding layer on the phase shift layer.

[0155] In the phase-shift layer formation process, sputtering can be performed using a sputtering chamber in which the light-transmitting substrate and a sputtering target are arranged. In this way, the phase-shift layer can be formed on the light-transmitting substrate.

[0156] A description of the translucent substrate overlaps the content described above and is therefore omitted.

[0157] In the phase shift layer forming process, the sputtering target may be applied taking into account a composition of the phase shift layer to be formed.

[0158] In the phase-shift layer formation process, a sputtering target containing both a transition metal and silicon may be deposited. In the phase-shift layer formation process, two or more sputtering targets, including a sputtering target containing a transition metal and a sputtering target containing silicon, may be deposited.

[0159] When a sputtering target is applied during the phase-shift layer formation process, the transition metal content of the sputtering target may be 30 atomic% or less. The transition metal content may be 20 atomic% or less. The transition metal content may be 2 atomic% or more.

[0160] The silicon content of the sputtering target can be 70 atomic percent or more. The silicon content can be 80 atomic percent or more. The silicon content can be 98 atomic percent or less.

[0161] During the phase-shift layer formation process, an atmospheric gas may be injected into the sputtering chamber. The atmospheric gas may include an inert gas and a reactive gas. The inert gas is a gas that does not contain elements that form the formed thin film layer. The reactive gas is a gas that contains elements that form the formed thin film layer.

[0162] The inert gas may include a gas that is ionized in a plasma atmosphere and collides with the sputtering target. The inert gas may include argon. The inert gas may also include helium for the purpose of voltage control of a thin film layer to be formed.

[0163] The atmospheric gas may contain 2 vol% or more argon. The atmospheric gas may contain 5 vol% or more argon. The atmospheric gas may contain 30 vol% or less argon. The atmospheric gas may contain 20 vol% or less argon.

[0164] The atmospheric gas may contain 20 vol% or more helium. The atmospheric gas may contain 25 vol% or more helium. The atmospheric gas may contain 30 vol% or more helium. The atmospheric gas may contain 60 vol% or less helium. The atmospheric gas may contain 55 vol% or less helium. The atmospheric gas may contain 50 vol% or less helium.

[0165] The reactive gas may include a gas containing the element nitrogen. Examples of the gas containing the element nitrogen may include N2, NO, NO2, N2O, N2O3, N2O4, and N2O5 gases. The reactive gas may include a gas containing the element oxygen. Examples of the gas containing the element oxygen may include O2 and CO2 gases. The reactive gas may include a gas containing the element nitrogen and a gas containing the element oxygen. The reactive gas may include a gas containing both the element nitrogen and the element oxygen. Examples of the gas containing both the element nitrogen and the element oxygen may include NO, NO2, N2O, N2O3, N2O4, and N2O5 gases.

[0166] The atmospheric gas may contain 20 vol% or more of reactive gas. The atmospheric gas may contain 30 vol% or more of reactive gas. The atmospheric gas may contain 40 vol% or more of reactive gas. The atmospheric gas may contain 80 vol% or less of reactive gas.

[0167] In the phase-shift film formation process, a T / S distance, which is the distance between a target and a substrate, can range from 240 mm to 260 mm. The angle between the substrate and the target can range from 20° to 30°. The rotational speed of the substrate can range from 2 revolutions per minute (rpm) to 20 rpm.

[0168] In the phase-shift layer formation process, sputtering can be performed by applying power to the sputtering target. A power source for applying power to the sputtering target can be a DC power source or a radio frequency (RF) power source.

[0169] The power applied to the sputtering target can range from 1 kW to 3 kW. The power can range from 1.5 kW to 2.5 kW. The power can range from 1.8 kW to 2.2 kW.

[0170] In the phase shift layer forming process, sputtering may be performed for 600 seconds or more and 800 seconds or less.

[0171] When forming the phase shift layer, a mask shield may be disposed on the light-transmitting substrate. The mask shield may include an opening and a shielding portion surrounding the opening. In this case, during sputtering, the mask shield can allow sputter particles to pass toward the opening and prevent particles sputtering toward the shielding portion from being deposited on the substrate. In this way, it is possible to control the shape and area of ​​the phase shift layer to be formed.

[0172] A ratio of an area of ​​the opening of the mask shield to an area of ​​a top surface of the substrate that is a deposition target may be 0.98 or less. The ratio may be 0.95 or less. The ratio may be 0.93 or less. The ratio may be 0.5 or more.

[0173] The opening of the mask shield may have a square shape. The ratio of a length of one side of the opening of the mask shield to a length of one side of the substrate, which is a deposition target, may be 0.98 or less. The ratio may be 0.7 or more. The ratio may be 0.8 or more.

[0174] In the phase-shift layer formation process, the mask shield may be positioned 0.5 mm or more away from the top surface of the substrate that is a deposition target. The mask shield may be positioned 1 mm or more away from the top surface of the substrate that is a deposition target. The mask shield may be positioned 5 mm or less away from the top surface of the substrate that is a deposition target.

[0175] In these cases, the shape and area of ​​the phase shift layer can be controlled to easily protect one side surface of the phase shift layer by forming the light-shielding layer.

[0176] The material of the mask shield is not limited as long as it is applicable to the sputtering area. For example, the material of the mask shield can be an aluminum alloy.

[0177] The formed phase shift layer can be heat treated to relieve internal stresses and improve light resistance.

[0178] The method for manufacturing a mask blank includes a light-shielding layer forming process of forming a light-shielding layer on the phase shift layer.

[0179] A sputtering target applied in the light-shielding layer formation process may contain 90 wt% or more of at least one of Cr, Ta, Ti, and Hf. The sputtering target may contain 95 wt% or more of at least one of Cr, Ta, Ti, and Hf. The sputtering target may contain 99 wt% or more of at least one of Cr, Ta, Ti, and Hf.

[0180] The sputtering target applied in the light-shielding layer formation process may contain 90 wt% or more Cr. The sputtering target may contain 95 wt% or more Cr. The sputtering target may contain 99 wt% or more Cr. The sputtering target may contain 100 wt% or less Cr.

[0181] The light-shielding layer formation process may include a first light-shielding layer formation process and a second light-shielding layer formation process. In the light-shielding layer formation process, a sputtering process condition may be applied differently to each layer included in the light-shielding layer. Specifically, different process conditions, such as the composition of an atmospheric gas, the power applied to the sputtering target, and the formation time, may be applied to the layers, taking into account the light extinction characteristics and etching characteristics required for the layers.

[0182] The atmospheric gas may include an inert gas and a reactive gas.

[0183] The inert gas may include a gas that is ionized in a plasma atmosphere and collides with the sputtering target. The inert gas may include argon. The inert gas may also include helium for the purpose of voltage control of a thin film layer to be formed.

[0184] The reactive gas may include a gas containing the element nitrogen. Examples of the gas containing the element nitrogen may include N2, NO, NO2, N2O, N2O3, N2O4, and N2O5 gases. The reactive gas may include a gas containing the element oxygen. Examples of the gas containing the element oxygen may include O2 and CO2 gases. The reactive gas may include a gas containing the element nitrogen and a gas containing the element oxygen. The reactive gas may include a gas containing both the element nitrogen and the element oxygen. Examples of the gas containing both the element nitrogen and the element oxygen may include NO, NO2, N2O, N2O3, N2O4, and N2O5 gases.

[0185] When the light-shielding layer is formed in the light-shielding layer forming process, a mask shield may be disposed on the phase shift layer.

[0186] A ratio of an opening area of ​​the mask shield applied in the light-shielding layer formation process to the opening area of ​​the mask shield applied in the phase-shifting layer formation process may be 1.01 or more. The ratio may be 1.02 or more. The ratio may be 1.03 or more. The ratio may be 5 or less.

[0187] The openings of the mask shields formed in the phase shift layer formation process and the light-shielding layer formation process may each have a square shape. A ratio of a length of one side of the opening of the mask shield formed in the light-shielding layer formation process to the length of one side of the opening of the mask shield formed in the phase shift layer formation process may be 1.005 or more. The ratio may be 1.01 or more. The ratio may be 2.3 or less.

[0188] In the light-shielding layer formation process, the mask shield may be positioned 0.5 mm or more away from the upper surface of the substrate that is a deposition target. The mask shield may be positioned 1 mm or more away from the upper surface of the substrate that is a deposition target. The mask shield may be positioned 5 mm or less away from the upper surface of the substrate that is a deposition target.

[0189] In these cases, it is possible to stably protect the phase shift layer from a cleaning solution and form a multilayer with a reduced frequency of particle generation.

[0190] The material of the mask shield is not limited as long as it is applicable to the sputtering area. For example, the material of the mask shield can be an aluminum alloy.

[0191] In the first light-shielding layer formation process, the power applied to the sputtering target may be 1.5 kW or more and 2.5 kW or less. The power applied to the sputtering target may be 1.6 kW or more and 2 kW or less.

[0192] In the first light-shielding layer formation process, a ratio of a flow rate of the reactive gas to a flow rate of the inert gas in the atmospheric gas may be 0.5 or more. The flow rate ratio may be 0.7 or more. The flow rate ratio may be 1.5 or less. The flow rate ratio may be 1.2 or less. The flow rate ratio may be 1 or less.

[0193] In the atmospheric gas, the ratio of the Ar gas flow rate to the total inert gas flow rate may be 0.2 or more. The flow rate ratio may be 0.25 or more. The flow rate ratio may be 0.3 or more. The flow rate ratio may be 0.55 or less. The flow rate ratio may be 0.5 or less. The flow rate ratio may be 0.45 or less.

[0194] In the atmospheric gas, the ratio of oxygen content to nitrogen content contained in the reactive gas may be 1.5 or more and 4 or less. The ratio may be 1.8 or more and 3.8 or less. The ratio may be 2 or more and 3.5 or less.

[0195] In these cases, the formed first light-shielding layer can help ensure that the light-shielding layer has sufficient light extinction properties. Furthermore, the formed first light-shielding layer can help precisely control the shape of the light-blocking pattern layer during the light-shielding layer patterning process.

[0196] The first light-shielding layer formation process may be performed for a time of 200 seconds or more and 300 seconds or less. The first light-shielding layer formation process may be performed for a time of 230 seconds or more and 280 seconds or less. In these cases, the formed first light-shielding layer can contribute to the light-shielding layer having sufficient light extinction properties.

[0197] In the second light-shielding layer formation process, the power applied to the sputtering target can be in the range of 1 kW to 2 kW. The power can be in the range of 1.2 kW to 1.7 kW. In these cases, the impact resistance of the second light-shielding layer can be further improved, and thus, the second light-shielding layer can contribute to the light-shielding layer having desired optical and etching properties.

[0198] In the second light-shielding layer formation process, a ratio of a flow rate of the reactive gas to a flow rate of the inert gas contained in the atmospheric gas may be 0.4 or more. The flow rate ratio may be 0.5 or more. The flow rate ratio may be 0.65 or more. The flow rate ratio may be 1 or less. The flow rate ratio may be 0.9 or less. The flow rate ratio may be 0.8 or less.

[0199] In the atmospheric gas, the ratio of the Ar gas flow rate to the total inert gas flow rate may be 0.8 or more. The flow rate ratio may be 0.9 or more. The flow rate ratio may be 0.95 or more. The flow rate ratio may be 1 or less.

[0200] In the second light-shielding layer formation process, the ratio of the oxygen content to the nitrogen content contained in the reactive gas may be 0.3 or less. The ratio may be 0.1 or less. The ratio may be 0.001 or more. The ratio may be 0 or more.

[0201] In these cases, a surface of the light-shielding layer can exhibit stable durability and excellent light extinction properties.

[0202] The second light-shielding layer formation process can be performed for a time of 10 seconds or more and 30 seconds or less. The second light-shielding layer formation process can be performed for a time of 15 seconds or more and 25 seconds or less. In these cases, a light-shielding layer with excellent durability can be formed, and the pattern of the light-shielding layer can be implemented more elaborately.

[0203] A heat treatment can be performed on the multilayer to relieve internal stresses of the light-shielding layer. Method for manufacturing a semiconductor device

[0204] A method of manufacturing a semiconductor device according to another embodiment of the present invention includes a preparation process of arranging a light source, a photomask, and a semiconductor wafer on which a resist layer is deposited, an exposure process of selectively transmitting and emitting light incident from the light source through the photomask onto the semiconductor wafer, and a development process of developing a pattern on the semiconductor wafer.

[0205] The photomask is implemented from the raw mask.

[0206] In the preparation process, the light source is a device that can generate exposure light with a short wavelength. The exposure light can be light with a wavelength of 200 nm or less. The exposure light can be ArF light with a wavelength of 193 nm.

[0207] A lens may additionally be arranged between the photomask and the semiconductor wafer. The lens functions to reduce the shape of the circuit pattern on the photomask and transfer the reduced circuit pattern shape to the semiconductor wafer. The lens is not limited as long as it can generally be used in an ArF semiconductor wafer exposure process. For example, a lens made of calcium fluoride (CaF2) can be used as the lens.

[0208] During the exposure process, the exposure light may be selectively transmitted to the semiconductor wafer through the photomask. In this case, chemical degradation may occur in a portion of the resist layer onto which the exposure light is incident.

[0209] In the development process, the pattern on the semiconductor wafer can be developed by treating the semiconductor wafer, which has undergone the exposure process, with a developer. If the applied resist layer is a positive resist, the portion of the resist layer on which the exposure light is incident can be dissolved by the developer. If the applied resist layer is a negative resist, a portion of the resist layer on which the exposure light is not incident can be dissolved by the developer. The resist layer is formed into a resist pattern by the developer treatment. A pattern can be formed on the semiconductor wafer using the resist pattern as a mask.

[0210] A description of the photomask overlaps the content described above and is therefore omitted.

[0211] Specific examples are described in more detail below. Manufacturing examples: Formation of a light-shielding layer

[0212] Example 1: A transparent quartz substrate measuring 6 inches horizontally by 6 inches vertically, with a thickness of 0.25 inches and a flatness of less than 500 nm, was placed in a chamber of a DC sputtering apparatus. A 0.45 mm wide chamfer was applied to one edge of the transparent substrate. A sputtering target was placed in the chamber so that the T / S distance was 255 mm and the angle between the substrate and the target was 25 degrees. The sputtering target contained 10 atomic percent molybdenum and 90 atomic percent silicon.

[0213] An aluminum alloy mask shield with an opening of 149.4 mm horizontally and 149.4 mm vertically was placed on the translucent substrate. The mask shield was positioned 2 mm from the top surface of the translucent substrate.

[0214] Thereafter, an atmospheric gas mixed in a ratio of Ar:N2:He = 9:52:39 was introduced into the chamber, the sputtering power was set to 2 kW, and the formation of the phase shift layer was carried out for a time of 600 seconds or more and 800 seconds or less.

[0215] The phase shift layer after formation was annealed at 1 Pa and a temperature of 400 °C for 30 minutes and then naturally cooled.

[0216] Example 2: A phase shift layer was formed on the light-transmitting substrate under the same conditions as in Example 1. A first light-shielding layer was formed on the phase shift layer. When the first light-shielding layer was formed, a chromium target was used as the sputtering target, and the same T / S distance and angle between the substrate and the target were applied as in the case of the phase shift layer formation.

[0217] When the first light-shielding layer was formed, an aluminum alloy mask shield with an opening of 151.4 mm horizontally and 151.4 mm vertically was placed on the phase shift layer. The mask shield was placed at a position 2 mm away from a top surface of the phase shift layer.

[0218] In the first light-shielding layer forming process, an atmospheric gas in which 19 vol% Ar, 11 vol% N2, 36 vol% CO2 and 34 vol% He were mixed was introduced into the chamber, and the first light-shielding layer was formed by performing a sputtering process for 250 seconds by applying power of 1.85 kW to the sputtering target.

[0219] After the formation of the first light-shielding layer was completed, an atmospheric gas containing 57 vol% Ar and 43 vol% N2 was introduced onto the first light-shielding layer in the chamber, and a second light-shielding layer was formed by sputtering for 25 seconds by applying 1.5 kW of power to the sputtering target. When forming the second light-shielding layer, the same mask-shielding arrangement conditions as for the first light-shielding layer were applied.

[0220] A blank mask in which the formation of the second light-shielding layer was completed was placed in a heat treatment chamber. A heat treatment was then performed for 15 minutes by applying an ambient temperature of 250 °C.

[0221] Comparative Example 1: A blank mask was prepared in the same manner as in Example 2, except that a mask shield was not applied when a phase shift layer and a light shielding layer were formed. Evaluation example: Measurement of surface profiles of phase shift coatings and multilayer

[0222] Surface profiles of the phase shift layer of Example 1 and the multilayer of Example 2 were measured. Specifically, a point 0.5 mm from the edge of the mask for each sample in an inward direction of the mask was set as a measurement start point. A surface profile of the thin film layer (i.e., a thickness of the thin film layer at each position) was measured at intervals of 0.1 mm in a section from the start point to a point 4 mm away in the inward direction of the mask. The surface profile was measured using a Dektak 150 surface profilometer manufactured by Veeco Instruments Inc. During measurement, a stylus radius was set to 12.5 µm, a force was set to 3.00 mg, and a Hills & Valleys measurement method was applied.

[0223] A thickness of the phase shift layer for each position of the phase shift layer in Example 1 and a thickness, a dT value, and a ddT value for each position of the multilayer in Example 2 are shown in Table 1 below, and a maximum value of the dT value and a maximum value of the ddT value in Example 2 are shown in Table 2 below. A graph showing the surface profiles measured from Examples 1 and 2 is shown in Fig. 6 shown. Evaluation example: Evaluation of the degree of damage of the phase shift layer according to the cleaning process

[0224] The blank masks of Example 2 and Comparative Example 1 were immersed in a Standard Clean-1 (SC-1) solution for 800 seconds and cleaned using ozone water. A solution containing 14.3 wt% NH4OH, 14.3 wt% H2O2, and 71.4 wt% H2O was applied as the SC-1 solution.

[0225] Then, a cross-section of the mask was observed by TEM. If damage to the phase shift layer was not observed from the cross-sectional image of the raw mask, it was rated as P, and if damage to the phase shift layer was observed, it was rated as F.

[0226] The measured results for each example and the comparative example are shown in Table 3 below. Evaluation example: Particle evaluation

[0227] The number of observed particles was measured by measuring the image of the upper surface of the multilayer of each example and the comparative example. Specifically, a sample for each example and the comparative example was placed in a Raytec Corporation M6641S defect inspection system. Then, the number of particles was measured within a range of 146 mm horizontally and 146 mm vertically in the upper surface of the multilayer. When measuring the number of particles, the inspection light was a green laser with a wavelength of 532 nm, the laser power was 3000 mW (a laser power was 1050 mW when measured on one surface of a substrate to be measured), and the step movement speed was set to 2.

[0228] The samples for each example and the comparative example were then stored in a standard mechanical interface (SMIF) container for one week and then opened inside the defect inspection system. Additionally, the number of particles on the upper surface of the multilayer was measured under the same conditions as when the number of particles was measured before storage in the SMIF container.

[0229] Compared to the samples before being stored in the SMIF container, each sample was rated as F if an increase in the number of particles detected in the sample after being stored in the SMIF container was observed and was rated as P if no increase in the number of particles was observed.

[0230] The measured results for each example and the comparative example are shown in Table 3 below. [Table 1] Example 1 Example 2 Measuring position (distance between starting point of the measuring section and measuring point (mm)) Thickness of the phase shift layer (nm) Thickness of the multilayer (nm) dT (nm) ddT (nm) 0 0 1,95 0 0 0,1 0 2,91 0,96 0 0,2 0 8,38 5,47 4,51 0,3 0 10,68 2,30 3,17 0,4 0 24,71 14,03 11,74 0,5 0 44,82 20,11 6,07 0,6 0 43,82 -1,00 21,11 0,7 0 44,36 0,54 1,54 0,8 0 47,04 2,68 2,15 0,9 0 48,83 1,78 0,90 1 0 49,40 0,58 1,20 1,1 0 46,49 -2,91 3,49 1,2 0 48,34 1,85 4,76 1,3 0 44,80 -3,55 5,40 1,4 0 44,60 -0,20 3,35 1,5 0 44,73 0,13 0,32 1,6 0 45,76 1,03 0,90 1,7 0 49,84 4,08 3,05 1,8 0 49,71 -0,13 4,21 1,9 1,66 47,57 -2,14 2,01 2 2,89 55,63 8,06 10,20 2,1 4,32 63,31 7,68 0,38 2,2 12,44 62,85 -0,46 8,14 2,3 15,85 66,65 3,80 4,26 2,4 36,69 87,29 20,64 16,84 2,5 66,54 111,27 23,98 3,34 2,6 69,22 114,98 3,71 20,27 2,7 67,11 116,95 1,97 1,74 2,8 68,49 118,20 1,25 0,72 2,9 70,18 120,22 2,02 0,77 3 69,73 122,28 2,06 0,04 3,1 69,59 122,30 0,02 2,04 3,2 65,38 117,19 -5,11 5,13 3,3 62,83 115,13 -2,06 3,05 3,4 64,21 113,74 -1,39 0,67 3,5 63,46 113,74 0,00 1,39 3,6 65,00 114,74 1,00 1,00 3,7 68,39 118,14 3,40 2,40 3,8 63,92 117,48 -0,66 4,06 3,9 68,51 119,27 1,79 2,45 4 71,03 121,02 1,75 0,04 [Table 2] Maximum value of the dT value (nm) Maximum ddT value (nm) Example 2 23,98 21,11 [Table 3] Assess whether the phase shift layer is damaged Particle assessment Example 2 P P Comparison example 1 F F

[0231] In Table 3, Example 2 was rated P in both phase shift layer damage evaluation and particle evaluation, while Comparative Example 1 was rated F in both phase shift layer damage evaluation and particle evaluation.

[0232] According to a mask blank according to the embodiments, damage to a phase shift layer due to a cleaning solution can be substantially prevented, and a frequency of particle generation resulting from a phase shift layer and a light-shielding layer can be effectively reduced.

[0233] Although the exemplary embodiments of the present invention have been described in detail, the scope of the present invention is not limited to these embodiments, and various modifications and improvements developed by those skilled in the art using the basic concept of the exemplary embodiments of the present invention defined by the appended claims are also within the scope of the present invention. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] KR 1020220103470

[0001]

Claims

[1] Raw mask, comprising: a translucent substrate; and a multilayer arranged on the light-transmitting substrate, wherein the multilayer comprises a light-shielding layer disposed on the light-transmitting substrate and a phase shift layer disposed between the light-transmitting substrate and the light-shielding layer and comprising an upper surface facing the light-shielding layer and a side surface connected to the upper surface, the light-shielding layer is arranged to cover the top surface and the side surface of the phase shift layer, viewed from the upper surface of the multilayer, the multilayer comprises a central portion and an outer portion surrounding the central portion, and the outer portion has a curved upper surface. [2] A blank mask according to claim 1, wherein: the light-transmitting substrate comprises an upper surface facing the phase shift layer; and the light-shielding layer is arranged to cover at least a portion of the upper surface of the light-transmitting substrate. [3] A blank mask according to claim 2, wherein: the light-transmissive substrate further comprises a side surface connected to the top surface of the light-transmissive substrate; the side surface of the light-transmitting substrate includes a first surface curved to extend from the top surface of the light-transmitting substrate and a second surface extending from the first surface in a vertical direction of the mask blank; and the light-shielding layer is arranged to cover at least a portion of the first surface of the light-transmitting substrate. [4] The blank mask according to claim 1, wherein, viewed from the upper surface of the multilayer, a region A of the light-transmitting substrate, a region B of the light-shielding layer, and a region C of the phase shift layer satisfy the following equation 1: A≥B>C. [5] The mask blank according to claim 1, wherein the outer portion of the multilayer includes a slope region in which a thickness of the multilayer continuously increases from an edge of the multilayer in an inward direction of the multilayer. [6] A blank mask according to claim 5, wherein: the inclination region is arranged at an outermost portion of the multilayer; and viewed from a cross-section of the multilayer, the inclination region has a width in the range of 0.2 mm to 1.0 mm in a direction in the plane of the multilayer. [7] A blank mask according to claim 5, wherein among dT values ​​according to equation 2, measured from the multilayer, a maximum value is in the range of 10 nm to 30 nm: dT=T1−T2, and in Equation 2, T1 denotes a thickness of the multilayer measured at a first point located in the multilayer, and T2 denotes a thickness of the multilayer measured at a second point located 0.1 mm away from the first point in a direction of an edge of the multilayer. [8] The blank mask according to claim 1, wherein among ddT values ​​according to equation 3, measured from the multilayer, a maximum value is 30 nm or less: ddT=|(T1−T2)−(T2−T3)|, and in Equation 3, T1 denotes a thickness of the multilayer measured at a first point located in the multilayer, T2 denotes a thickness of the multilayer measured at a second point located 0.1 mm away from the first point in a direction of one edge of the multilayer, and T3 denotes a thickness of the multilayer measured at a third point located 0.1 mm away from the second point in the direction of one edge of the multilayer. [9] A blank mask according to claim 1, wherein: the multilayer comprises a lower surface facing the light-transmissive substrate; the phase shift layer comprises a lower surface facing the light-transmitting substrate; viewed from a cross-section, the lower surface (lower boundary) of the multilayer comprises a first edge, which is one end, and a second edge, which is the other end opposite the first edge, and the lower surface (lower boundary) of the phase shift layer comprises a third edge, which is one end positioned adjacent to the first edge, and a fourth edge, which is the other end positioned adjacent to the second edge; and the smaller value of a distance value between the first edge and the third edge and a distance value between the second edge and the fourth edge is 0.1 nm or more. [10] A photomask made from the blank mask according to claim 1. [11] A method of manufacturing a semiconductor device, comprising: a preparation process of arranging a light source, a photomask, and a semiconductor wafer on which a resist layer is applied; an exposure process of selectively transmitting and emitting light incident from the light source through the photomask onto the semiconductor wafer; and a developing process of developing a pattern on the semiconductor wafer, wherein the photomask is made from the mask blank according to claim 1.