Mask blank substrate, substrate with conductive film, substrate with multilayer reflective film, reflective mask blank, reflective mask, and method for manufacturing semiconductor device

Abstract

Provided is a substrate which is for a mask blank and of which the surface shape can be accurately calculated after being set on a mask stage of an exposure device.　A substrate 10 for a mask blank comprises: a first main surface 12a which is a surface having a transfer pattern formed thereon; and a second main surface 12b which faces the first main surface 12a and is a surface on a side that is electrostatically chucked to a mask stage of an exposure device. The first main surface 12a includes a first region 20a located on the center side and a second region 20b located outside the first region 20a. The second main surface 12b includes a third region 20c located on the center side and a fourth region 20d located outside the third region 20c. An angle α formed by the plane having the least squares of the first region 20a and the plane having the least squares of the third region 20c is less than 1. 2°. The PV values of the surfaces of the second region 20b and the fourth region 20d are 400 nm or less.

Description

[Technical field]

[0001] The present invention relates to a mask blank substrate, a substrate with a conductive film, a substrate with a multilayer reflective film, a reflective mask blank, a reflective mask, and a method for manufacturing a semiconductor device. [Background technology]

[0002] In general, in the manufacturing process of semiconductor devices, fine patterns are formed by photolithography. To form these fine patterns, a number of transfer masks, usually called photomasks, are used. These transfer masks are generally formed by providing a fine pattern made of a metal thin film or the like on a light-transmitting glass substrate, and photolithography is also used to manufacture these transfer masks.

[0003] In the manufacture of a transfer mask by photolithography, a mask blank having a thin film (e.g., a light-shielding film, etc.) for forming a transfer pattern (mask pattern) on a light-transmitting substrate such as a glass substrate is used. The method of manufacturing a transfer mask using this mask blank includes a drawing step of drawing a desired pattern on a resist film formed on the mask blank, a development step of developing the resist film after drawing to form a desired resist pattern, an etching step of etching the thin film using the resist pattern as a mask, and a step of peeling and removing the remaining resist pattern. In the development step, a desired pattern is drawn on the resist film formed on the mask blank, and then a developer is supplied. As a result, the parts of the resist film that are soluble in the developer are dissolved, and thus a resist pattern is formed. In the etching step, the resist pattern is used as a mask to remove the exposed parts of the thin film that are not covered by the resist pattern by dry etching or wet etching. As a result, a desired mask pattern is formed on the light-transmitting substrate.

[0004] As a type of transfer mask, in addition to a conventional binary type mask having a light-shielding film pattern made of a chromium-based material on a light-transmitting substrate, a phase shift type mask is known. This phase shift type mask has a light-transmitting substrate and a phase shift film formed on the light-transmitting substrate. This phase shift film has a predetermined phase difference and is formed of a material containing a molybdenum silicide compound, for example. In addition, binary type masks using a material containing a silicide compound of a metal such as molybdenum as a light-shielding film have also come to be used. These binary type masks and phase shift type masks are collectively referred to as transmission type masks in this specification. Also, binary type mask blanks and phase shift type mask blanks, which are originals used in transmission type masks, are collectively referred to as transmission type mask blanks.

[0005] In recent years, in the semiconductor industry, with the increasing integration of semiconductor devices, fine patterns exceeding the transfer limit of conventional photolithography using ultraviolet light are required. To enable the formation of such fine patterns, EUV lithography, an exposure technology using extreme ultraviolet (hereinafter referred to as "EUV") light, is considered promising. Here, EUV light refers to light in a wavelength band in the soft X-ray region or the vacuum ultraviolet region, specifically light with a wavelength of about 0.2 to 100 nm. As a transfer mask used in this EUV lithography, a reflective mask has been proposed. In such a reflective mask, a multilayer reflective film that reflects exposure light is formed on a substrate, and an absorber film that absorbs exposure light is formed on the multilayer reflective film. A transfer pattern is formed on the absorber film of the reflective mask.

[0006] Patent Document 1 discloses a reflective mask blank having a multilayer reflective film that reflects exposure light on a substrate, and an absorber layer that absorbs exposure light formed on the multilayer reflective film, characterized in that the shape of the surface of the mask blank opposite to the surface on which a transfer pattern is formed is a convex shape. It is disclosed that this reflective mask blank can solve the problem of poor chucking when fixing a reflective mask to a mask stage of an exposure tool by an electrostatic chuck. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2008-103481 A Summary of the Invention [Problem to be solved by the invention]

[0008] When a reflective mask is used to transfer a transfer pattern onto a transfer target such as a semiconductor substrate, the reflective mask is set on the mask stage of an exposure tool with the surface on which the transfer pattern is formed facing downwards. A conductive film is formed on the surface (back surface) of the reflective mask opposite to the surface on which the transfer pattern is formed, for adhering the reflective mask to the mask stage of the exposure tool by an electrostatic chuck.

[0009] Therefore, when the reflective mask is set on the mask stage of the exposure tool, almost the entire back surface of the reflective mask is attracted to the mask stage of the exposure tool by the electrostatic chuck. While the mask stage of the exposure tool is flat, the back surface of the reflective mask is not completely flat and has irregularities. Therefore, the irregular shape of the back surface of the reflective mask is transferred to the surface (front surface) of the reflective mask on which the transfer pattern is formed.

[0010] For example, if a convex shape exists on the back surface of a reflective mask, when that convex shape is pressed downward by the mask stage, the surface of the reflective mask opposite the position of the convex shape is deformed downward by an amount equal to the height of the convex shape.

[0011] Conversely, for example, if a concave shape exists on the back surface of the reflective mask, the reflective mask will be pulled upward toward the mask stage by the amount of the concave shape, and the surface of the reflective mask facing the position of the concave shape will be deformed upward by the depth of the concave shape.

[0012] As described above, conventional reflective masks had the problem that the shape of the main surface on which the transfer pattern is formed changes before and after being set on the mask stage of an exposure tool, making it difficult to accurately transfer the transfer pattern onto a transfer target such as a semiconductor substrate.

[0013] In order to solve such problems, it is conceivable to measure the shapes of the front and back surfaces of the mask blank substrate (or reflective mask blank, reflective mask) in advance by a surface shape measuring device, and calculate the surface shape of the mask blank substrate (or reflective mask blank, reflective mask) after it has been set on the mask stage of the exposure tool by simulation from the data obtained by the measurement. If the surface shape of the mask blank substrate (or reflective mask blank, reflective mask) after it has been set on the mask stage can be known in advance by simulation, the shape of the transfer pattern drawn by the drawing device can be corrected, thereby controlling the shape of the transfer pattern after the reflective mask is set on the mask stage of the exposure tool to be a desired shape.

[0014] However, the front and back surfaces of a mask blank substrate are not completely parallel, which makes it difficult to accurately match shape data of the front surface measured by a surface shape measuring device with shape data of the back surface of a conventional mask blank substrate.

[0015] That is, when the surface shape of a mask blank substrate (or a reflective mask blank, a reflective mask) is measured by a surface shape measuring device, the surface is divided into a plurality of regions in a grid pattern (e.g., 197 μm×197 μm regions), and the surface shape is measured for each divided region. However, since the front and back surfaces of the mask blank substrate are not completely parallel, it is difficult to accurately match shape data measured in a certain region on the front surface with shape data measured on the back surface at a position opposite to that region. For this reason, it is difficult to accurately calculate by simulation the surface shape of a mask blank substrate (or a reflective mask blank, a reflective mask) after it has been set on a mask stage.

[0016] The present invention has been made in consideration of the above-mentioned circumstances, and has an object to provide a mask blank substrate, a substrate with a conductive film, a substrate with a multilayer reflective film, a reflective mask blank, a reflective mask, and a method for manufacturing a semiconductor device, which enable accurate calculation of the surface shape after being set on a mask stage of an exposure tool. [Means for solving the problem]

[0017] In order to solve the above problems, the present invention has the following configuration. (1) A mask blank substrate having a substantially rectangular planar shape and a size of 152 mm × 152 mm, a first main surface on which a transfer pattern is formed, and a second main surface opposed to the first main surface and fixed to a mask stage of an exposure apparatus; the first main surface includes a first region located toward the center and a second region located outside the first region, the second main surface includes a third region located toward the center and a fourth region located outside the third region, an angle α between a least squares plane of the first region and a least squares plane of the third region is less than 1.2°; A mask blank substrate, wherein the PV value of the surfaces of the second region and the fourth region is 400 nm or less.

[0018] (2) The mask blank substrate according to (1), wherein the first region is a region in which the transfer pattern is formed and has a size of 132 mm x 132 mm or more based on the center of the substrate.

[0019] (3) The mask blank substrate according to (1) or (2), wherein the third region has a size of 142 mm x 142 mm or more based on the center of the substrate.

[0020] (4) A mask blank substrate according to any one of (1) to (3), wherein the second region and the fourth region are regions outside a 148 mm x 148 mm region based on the center of the substrate.

[0021] (5) The mask blank substrate according to any one of (1) to (4), wherein the mask blank substrate is a reflective mask blank substrate.

[0022] (6)(1 )mosquito A substrate with a conductive film, comprising a mask blank substrate according to any one of (1) to (5), the mask blank substrate having a conductive film on a second main surface thereof.

[0023] (7) A multilayer reflective film-coated substrate having a multilayer reflective film formed by alternately laminating high refractive index layers and low refractive index layers on a first main surface of a mask blank substrate according to any one of (1) to (6).

[0024] (8) A reflective mask blank having an absorber film serving as a transfer pattern on the multilayer reflective film of the multilayer reflective film-coated substrate according to (7).

[0025] (9) A reflective mask having an absorber pattern formed by patterning the absorber film on the multilayer reflective film in the reflective mask blank according to (8).

[0026] (10) A method for manufacturing a semiconductor device, comprising the step of performing a lithography process using an exposure apparatus with the reflective mask according to (9) to form a transfer pattern on a transfer target. [Brief description of the drawings]

[0027] [Figure 1] FIG. 2 is a perspective view of a mask blank substrate. [Diagram 2] FIG. 2 is a partial cross-sectional view of a mask blank substrate. [Diagram 3] FIG. 2 is a plan view of a first main surface. [Figure 4] FIG. 2 is a plan view of the second main surface. [Diagram 5] FIG. 1 is a schematic diagram for calculating the maximum distance that a point on a plane moves when the plane is rotated. [Figure 6] FIG. 1 is a schematic diagram showing a multilayer reflective film-coated substrate. [Figure 7] FIG. 1 is a schematic diagram showing a reflective mask blank. [Figure 8] FIG. 2 is a schematic diagram showing a reflective mask. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Hereinafter, an embodiment of the present invention will be described in detail. [Mask blank substrate] First, the mask blank substrate of this embodiment will be described. Fig. 1 is a perspective view showing a mask blank substrate 10 according to this embodiment. Fig. 2 is a partial cross-sectional view of the mask blank substrate 10 of this embodiment.

[0029] The mask blank substrate 10 (hereinafter sometimes simply referred to as substrate 10) is a plate-like body having a substantially rectangular (preferably square) shape with a size of 152 mm×152 mm. The mask blank substrate 10 has two main surfaces 12a, 12b and four end faces 14a-14d. In this specification, the surface on which a thin film that becomes a transfer pattern is formed is referred to as the first main surface 12a. The surface opposite to the first main surface 12a and electrostatically chucked to a mask stage of an exposure tool is referred to as the second main surface 12b.

[0030] In this specification, "upper" does not necessarily mean the upper side in the vertical direction. Moreover, "lower" does not necessarily mean the lower side in the vertical direction. These terms are merely used for the sake of convenience in explaining the positional relationship of members and parts.

[0031] The four end faces 14a to 14d are adjacent to the four sides of the substantially rectangular first main surface 12a and second main surface 12b, respectively. Each of the four end faces 14a to 14d has a side face 16 and two chamfered faces 18a, 18b (see FIG. 2) formed between the side face 16 and the main surfaces 12a, 12b.

[0032] The side surface 16 is a surface that is approximately perpendicular to the two main surfaces 12a, 12b, and is sometimes called a "T surface." The chamfered surfaces 18a, 18b are surfaces formed between the two main surfaces 12a, 12b and the side surface 16, and are formed by beveling. The chamfered surfaces 18a, 18b are sometimes called "C surfaces."

[0033] FIG. 3 is a plan view of the first main surface 12a. As shown in FIG. 3, the first main surface 12a includes a first region 20a located toward the center of the substrate 10, and a second region 20b located outside the first region 20a.

[0034] The first region 20a is a substantially rectangular region, and has a size of 132 mm×132 mm or more. "132 mm×132 mm" is the size of the region in which a transfer pattern is formed on a thin film when a transfer mask (e.g., a reflective mask) is manufactured using the mask blank substrate 10. "132 mm×132 mm" is the size of a square region with one side measuring 132 mm, with the center of the substrate 10 as the reference. Note that the following descriptions of the regions also refer to sizes with the center of the substrate 10 as the reference. The flatness of the first region 20a is preferably 100 nm or less, more preferably 50 nm or less, and further preferably 30 nm or less. The flatness is a numerical value (absolute value) that represents the height difference from the highest point to the lowest point of a plane based on a least square plane.

[0035] The second region 20b is a frame-shaped region located outside the first region 20a. The second region 20b is preferably a region outside a substantially rectangular region of 148 mm×148 mm located toward the center. "148 mm×148 mm" is the size of the region in which the flatness of the substrate 10 can be precisely measured by a surface shape measuring device. The second region 20b does not include the chamfered surface 18a.

[0036] FIG. 4 is a plan view of the second main surface 12b (rear surface). As shown in FIG. 4, the second main surface 12b includes a third region 20c located toward the center of the substrate 10, and a fourth region 20d located outside the third region 20c.

[0037] The third region 20c is a substantially rectangular region, and preferably has a size of 142 mm×142 mm or more. "142 mm×142 mm" is the size of a region in a transfer mask (e.g., a reflective mask) manufactured using the mask blank substrate 10, where the back surface is required to be flat, that is, the flatness of the back surface is required to be a predetermined value or less. The flatness of the third region 20c is preferably 100 nm or less, more preferably 50 nm or less, and even more preferably 30 nm or less.

[0038] The third region 20c preferably has a size of 146 mm×146 mm or less. "146 mm×146 mm" can be the size of the region where the second main surface 12b is attracted to the mask stage of the exposure tool by the electrostatic chuck. The region not attracted to the electrostatic chuck does not require a high degree of flatness, so the third region 20c preferably has a size of 146 mm×146 mm or less.

[0039] The fourth region 20d is a frame-shaped region located outside the third region 20c. The fourth region 20d is preferably a region outside the substantially rectangular region of 148 mm×148 mm located toward the center. "148 mm×148 mm" is the size of the region in which the flatness of the substrate 10 can be precisely measured by a surface shape measuring device. The fourth region 20d does not include the chamfered surface 18b.

[0040] The mask blank substrate 10 of this embodiment is characterized in that the angle α between the least squares plane of the first region 20a and the least squares plane of the third region 20c is less than 1.2°. Hereinafter, a method for determining the angle α will be described in detail.

[0041] First, the surface shape of the entire surface (152 mm×152 mm) of the first main surface 12a is measured by a surface shape measuring device. As the surface shape measuring device, a white light interferometer, a laser interferometer, a laser displacement meter, an ultrasonic displacement meter, a contact type displacement meter, etc. can be used, but it is preferable to use a white light interferometer (e.g., NewView6300 manufactured by Zygo) or a laser interferometer (e.g., UltraFlat200 manufactured by Tropel).

[0042] When measuring the surface shape of substrate 10 using a surface shape measuring device, the measurement can be performed with substrate 10 held nearly upright (for example, with substrate 10 tilted 2° from the vertical direction) in order to reduce distortion of substrate 10 due to gravity.

[0043] During the measurement, the first main surface 12a is divided into a plurality of regions (e.g., 33 μm×33 μm regions) in a grid pattern by the surface shape measuring device. Then, for each divided region, an arbitrary reference plane set by the surface shape measuring device and the distance (height) from this reference plane to the first main surface 12a are measured. A collection of height data measured for each region becomes shape data of the first main surface 12a.

[0044] After measuring the shape data of the first main surface 12a, the shape data obtained by the measurement is used to find a least-squares plane of the first region 20a. For example, when the reference plane for the measurement is the xy plane and the height direction from the reference plane is the z direction, the least-squares plane of the first region 20a can be found as a function of xyz (a1x + b1y + c1z + d1 = 0).

[0045] Next, shape data of the second main surface 12b (rear surface) is obtained using the shape data of the first main surface 12a and the thickness data of the substrate 10. That is, by using the shape data (height data) measured in a certain region of the first main surface 12a and the thickness data of the substrate 10 measured in the same region, the shape data (height data) of the second main surface 12b (rear surface) in that region can be obtained. A laser interferometer, for example, can be used to measure the thickness data of the substrate 10.

[0046] Alternatively, the shape data of the second main surface 12b (rear surface) may be measured using another method. For example, the shape data of the second main surface 12b (rear surface) may be measured using a three-dimensional shape measuring device.

[0047] After measuring the shape data of the second main surface 12b, the shape data obtained by the measurement is used to find a least-squares plane of the third region 20c. For example, when the reference plane for the measurement is the xy plane and the height direction from the reference plane is the z direction, the least-squares plane of the third region 20c can be found as a function of xyz (a2x + b2y + c2z + d2 = 0).

[0048] The angle α between the least squares plane (a1x + b1y + c1z + d1 = 0) of the first region 20a and the least squares plane (a2x + b2y + c2z + d2 = 0) of the third region 20c can be calculated, for example, by the following formula (1).

[0049]

number

[0050] In the mask blank substrate 10 of this embodiment, the angle α between the least squares plane of the first region 20a and the least squares plane of the third region 20c is set to less than 1.2° for the following reasons.

[0051] As shown in Figure 5, when a plane with a side length of L is rotated by an angle α, the length of the projection of the rotated plane onto the plane before rotation is L × cos α. In other words, when a plane is rotated by an angle α, the maximum distance (amount of deviation) that a point on the plane moves is P, as shown in the following formula (2).

[0052] P = LL × cosα (2)

[0053] As described above, when measuring the shape of the first main surface 12a by the surface shape measuring device, the first main surface 12a is divided into a plurality of regions in a grid pattern. If the size of one grid is Pg, and the condition "P < Pg" is satisfied, the amount of deviation does not exceed Pg, so that shape data measured in a certain region on the front side of the substrate can be accurately matched to shape data measured at a position opposite to that region on the back side.

[0054] If the size of the area where the flatness of the substrate 10 can be precisely measured by the surface profile measuring device is Lm, then by substituting Lm for L in the above formula (2), the maximum amount of deviation P when the plane measured by the surface profile measuring device is rotated by an angle α can be obtained. In other words, the maximum amount of deviation P is given by the following formula (3).

[0055] P = Lm-Lm×cosα (3)

[0056] By combining the above formula (3) with the aforementioned condition "P < Pg", the following formula (4) is obtained.

[0057] Lm-Lm×cosα < Pg (4)

[0058] Substituting 148 mm (=148,000 μm) for Lm and 33 μm for Pg in the above formula (4) gives a calculation result of α < 1.2°. The smaller the grid size, the more detailed shape data can be obtained, so Pg is preferably 33 μm or less, more preferably 24 μm or less, and even more preferably 15 μm or less. Note that if the grid size is made too small, it takes a long time to measure the shape data, so Pg is preferably 9 μm or more. Furthermore, the maximum deviation amount P is preferably Pg / 3 or less, and more preferably Pg / 5 or less.

[0059] From this result, the angle α between the least square plane of the first region 20a and the least square plane of the third region 20c is less than 1.2°. The angle α is preferably less than 1.0°, and more preferably less than 0.8°. If the angle α between the least square plane of the first region 20a and the least square plane of the third region 20c is less than 1.2°, it is possible to accurately match shape data measured in a certain region of the substrate front surface with shape data measured at a position opposite to that region.

[0060] In general, the surface shape is often disturbed in the peripheral region of the first main surface 12a due to the influence of processing the edge of the substrate 10. Therefore, when calculating the least squares plane, it is preferable to use shape data of the central region excluding the peripheral region, rather than the entire surface of the first main surface 12a. That is, when calculating the least squares plane of the first main surface 12a, it is preferable to use shape data of the first region 20a on the central side. The size of the first region 20a is preferably 132 mm x 132 mm or more, which is the size of the region where the transfer pattern is formed.

[0061] Also, in the peripheral region of the second main surface 12b, the surface shape is often disturbed due to the influence of processing the edge of the substrate 10. Therefore, when calculating the least squares plane, it is preferable to use shape data of the central region excluding the peripheral region, rather than the entire surface of the second main surface 12b. That is, when calculating the least squares plane of the second main surface 12b, it is preferable to use shape data of the third region 20c on the central side. The size of the third region 20c is preferably 142 mm×142 mm or more, which is the size of the region where the back surface of the substrate 10 is required to be flat (flatness is equal to or less than a predetermined value).

[0062] In the mask blank substrate 10 of this embodiment, the PV value of the surface of the second region 20b and the fourth region 20d is 400 nm or less, preferably 310 nm or less. The PV value of the second region 20b is a numerical value (absolute value) representing the height difference between the highest point and the lowest point of the plane based on the least square plane of the first region 20a. The PV value of the fourth region 20d is a numerical value (absolute value) representing the height difference between the highest point and the lowest point of the plane based on the least square plane of the third region 20c. The reason why the PV value of the surface of the second region 20b and the fourth region 20d is 400 nm or less is as follows.

[0063] A surface profile measuring device can measure the unevenness (height from a reference plane) of a substrate surface. However, if the slope of the outer peripheral surface of the substrate is greater than a certain level, it may be difficult to precisely measure the unevenness of the substrate surface using a surface profile measuring device. The maximum slope at which the unevenness of the substrate surface can be precisely measured using a surface profile measuring device is expressed by the following formula (5).

[0064] Z = β × X (5)

[0065] In the above formula (5), X represents the horizontal distance (mm) on the substrate. Z represents the height (μm) of the substrate surface. β is a value determined by the surface shape measuring device, but a small value is adopted for β so that the present invention can be applied regardless of the surface shape measuring device. In the case of a laser interferometer, β is, for example, 0.2178, and in the case of a white light interferometer, the value is larger than that.

[0066] In the first main surface 12a (152 mm x 152 mm), the second region 20b is the region outside the 148 mm x 148 mm region located on the central side. The width Wa of the chamfered surface 18a located on the outermost periphery of the first main surface 12a is 0.4 ± 0.2 mm. Therefore, the width of the second region 20b between them is as follows.

[0067] Maximum width of second region 20b = {152-148-(2×0.2)} / 2 = 1.8[mm] Minimum width of second region 20b = {152-148-(2×0.6)} / 2 = 1.4[mm]

[0068] In the second main surface 12b (152 mm x 152 mm), the fourth region 20d is an area outside the 148 mm x 148 mm area located on the center side. The width Wb of the chamfered surface 18b located on the outermost periphery of the second main surface 12b is 0.4 ± 0.2 mm. Therefore, the width of the fourth region 20d between them is as follows.

[0069] Maximum width of fourth region 20d = {152-148-(2×0.2)} / 2 = 1.8[mm] Minimum width of the fourth region 20d = {152-148-(2×0.6)} / 2 = 1.4[mm]

[0070] Therefore, the width of the second region 20b and the fourth region 20d is 1.4 to 1.8 mm.

[0071] By substituting β=0.2178 and X=1.4-1.8 into the above formula (5), Z=0.305-0.392 [μm] is obtained. From this result, when the absolute value of the change in height in the second region 20b and the fourth region 20d is smaller than 0.305-0.392 [μm], the slope of the outer periphery of the substrate is sufficiently small, so that the uneven shape of the substrate surface can be precisely measured by the surface shape measuring device.

[0072] That is, if the PV value of the surfaces of the second region 20b and the fourth region 20d is 400 nm or less (preferably 310 nm or less), the uneven shape of the substrate surface can be precisely measured by the surface shape measuring device.

[0073] The mask blank substrate 10 of this embodiment may be a transmission type mask blank substrate or a reflective type mask blank substrate.

[0074] The material of the transmission type mask blank substrate for ArF excimer laser exposure may be any material that is transparent to the exposure wavelength. Generally, synthetic quartz glass is used. Other materials that may be used include aluminosilicate glass, soda lime glass, borosilicate glass, and non-alkali glass.

[0075] The material of the reflective mask blank substrate for EUV exposure is preferably one having low thermal expansion properties. For example, so-called multi-component glass such as SiO2-TiO2 glass (binary (SiO2-TiO2) and ternary (SiO2-TiO2-SnO2, etc.)) and SiO2-Al2O3-Li2O crystallized glass can be used. In addition to the above glass, substrates such as silicon and metal can also be used. An example of the metal substrate is an Invar alloy (Fe-Ni alloy).

[0076] As described above, in the case of a mask blank substrate for EUV exposure, a multi-component glass material is used because the substrate is required to have low thermal expansion properties, but there is a problem that it is difficult to obtain high smoothness compared to synthetic quartz glass. To solve this problem, a thin film (underlayer) made of a metal or alloy, or any of these containing at least one of oxygen, nitrogen, and carbon, may be formed on a substrate made of a multi-component glass material.

[0077] As the material of the above-mentioned thin film, for example, Ta (tantalum), an alloy containing Ta, or a Ta compound containing at least one of oxygen, nitrogen, and carbon in any of these is preferable. As the Ta compound, for example, TaB, TaN, TaO, TaON, TaCON, TaBN, TaBO, TaBON, TaBCON, TaHf, TaHfO, TaHfN, TaHfON, TaHfCON, TaSi, TaSiO, TaSiN, TaSiON, TaSiCON, etc. can be applied. Among these Ta compounds, TaN, TaON, TaCON, TaBN, TaBON, TaBCON, TaHfN, TaHfON, TaHfCON, TaSiN, TaSiON, TaSiCON containing nitrogen (N) are more preferable.

[0078] In the mask blank substrate 10 of this embodiment, the processing method for satisfying the condition that the angle α between the least square plane of the first region 20a and the least square plane of the third region 20c is less than 1.2° is not particularly limited. In addition, the processing method for satisfying the condition that the PV value of the surfaces of the second region 20b and the fourth region 20d is 400 nm or less is not particularly limited.

[0079] The manufacturing method of the mask blank substrate 10 of this embodiment preferably includes the steps of measuring the surface shape of the first main surface 12a to obtain shape data of the first main surface 12a, calculating shape data of the second main surface 12b using the plate thickness data of the substrate 10, determining least squares planes of the first region 20a and the third region 20c from the shape data of the first main surface 12a and the second main surface 12b, respectively, and selecting a substrate 10 in which the angle α between the least squares plane of the first region 20a and the least squares plane of the third region 20c is less than 1.2° and the PV values ​​of the surfaces of the second region 20b and the fourth region 20d are 400 nm or less.

[0080] Alternatively, a conductive film 36 may be formed on the second main surface 12b of the selected substrate 10 to produce a substrate with a conductive film. A multilayer reflective film 32 in which high refractive index layers and low refractive index layers are alternately laminated may be formed on the first main surface 12a of the selected substrate 10 to produce a substrate with a multilayer reflective film. An absorber film 42 to be a transfer pattern may be formed on the multilayer reflective film 32 or protective film 34 on the first main surface 12a of the selected substrate 10 to produce a reflective mask blank.

[0081] [Substrate with conductive film] In the mask blank substrate 10 of this embodiment, a conductive film for adsorbing the transfer mask to a mask stage of an exposure tool by electrostatic chuck may be formed on the second main surface 12b. Note that the area of ​​the second main surface 12b that is adsorbed to the mask stage by electrostatic chuck is a 146 mm×146 mm area on the central side.

[0082] With a conductive film formed on the second main surface 12b of the substrate 10, shape data of the front and back surfaces of the substrate 10 may be measured. That is, shape data of the first main surface and the second main surface (back surface) of the substrate with a conductive film may be measured by a surface shape measuring device. From the shape data obtained by the measurement, the angle α between the least squares plane of the first region and the least squares plane of the third region may be obtained.

[0083] In the substrate with a conductive film of this embodiment, the angle α between the least square plane of the first region and the least square plane of the third region may be less than 1.2°. Moreover, the angle α is preferably less than 1.0°, and more preferably less than 0.8°.

[0084] That is, the present invention may have the following aspects. A substrate with a conductive film, the substrate having a substantially rectangular planar shape and a size of 152 mm×152 mm, the substrate comprising a first main surface on which a transfer pattern is formed, and a second main surface facing the first main surface and being a surface to be electrostatically chucked to a mask stage of an exposure tool, the second main surface having a conductive film for electrostatic chuck formed thereon, the first main surface includes a first region located toward the center and a second region located outside the first region, the second main surface includes a third region located toward the center and a fourth region located outside the third region, The substrate with a conductive film, wherein an angle α between a least squares plane of the first region and a least squares plane of the third region is less than 1.2°.

[0085] The method for manufacturing a substrate with a conductive film of this embodiment preferably includes the steps of forming a conductive film on the second main surface of a mask blank substrate, measuring the surface shape of the first main surface to obtain shape data of the first main surface, calculating shape data of the second main surface on which the conductive film is formed using thickness data of the substrate, determining least-squares planes of the first region and the third region from the shape data of the first main surface and the second main surface, respectively, and selecting a substrate with a conductive film in which the angle α between the least-squares plane of the first region and the least-squares plane of the third region is less than 1.2°.

[0086] Alternatively, a multilayer reflective film having high refractive index layers and low refractive index layers alternately laminated on a first main surface of a selected substrate with a conductive film may be formed to produce a substrate with a multilayer reflective film. A reflective mask blank may be produced by forming an absorber film to be a transfer pattern on the multilayer reflective film or protective film on the first main surface of the selected substrate with a conductive film.

[0087] [Substrate with multilayer reflective film] Next, the multilayer reflective film coated substrate of this embodiment will be described. FIG. 6 is a schematic diagram showing a multilayer reflective film coated substrate 30 of the present embodiment.

[0088] The multilayer reflective film-coated substrate 30 of this embodiment has a configuration in which a multilayer reflective film 32 is formed on the first main surface 12a on the side on which a transfer pattern is formed of the above-mentioned mask blank substrate 10. This multilayer reflective film 32 imparts a function of reflecting EUV light in a reflective mask for EUV lithography, and includes a multilayer film in which elements having different refractive indices are periodically laminated.

[0089] The material of the multilayer reflective film 32 is not particularly limited as long as it reflects EUV light, but the reflectance of the multilayer reflective film alone is usually 65% ​​or more, with the upper limit usually being 73%. Such a multilayer reflective film 32 generally includes a multilayer reflective film in which thin films made of a high refractive index material (high refractive index layers) and thin films made of a low refractive index material (low refractive index layers) are alternately stacked in about 40 to 60 periods.

[0090] For example, a Mo / Si periodic laminated film in which Mo films and Si films are alternately laminated for about 40 periods is preferable as the multilayer reflective film 32 for EUV light with a wavelength of 13 to 14 nm. Other examples of multilayer reflective films used in the EUV light region include a Ru / Si periodic multilayer film, a Mo / Be periodic multilayer film, a Mo compound / Si compound periodic multilayer film, a Si / Nb periodic multilayer film, a Si / Mo / Ru periodic multilayer film, a Si / Mo / Ru / Mo periodic multilayer film, and a Si / Ru / Mo / Ru periodic multilayer film.

[0091] The multilayer reflective film 32 can be formed by a method known in the art. For example, each layer can be formed by magnetron sputtering or ion beam sputtering. In the case of the Mo / Si periodic multilayer film described above, for example, a Si film having a thickness of about several nm is first formed on the substrate 10 by using a Si target by ion beam sputtering, and then a Mo film having a thickness of about several nm is formed by using a Mo target. This constitutes one period, and 40 to 60 periods are stacked to form the multilayer reflective film 32.

[0092] A protective film 34 (see FIG. 7) may be formed on the multilayer reflective film 32 formed as described above to protect the multilayer reflective film 32 from dry etching and wet cleaning in the manufacturing process of a reflective mask for EUV lithography.

[0093] Examples of materials for the protective film 34 include materials containing at least one selected from the group consisting of Ru, Ru-(Nb,Zr,Y,B,Ti,La,Mo), Si-(Ru,Rh,Cr,B), Si,Zr,Nb,La, and B. Among these, when a material containing ruthenium (Ru) is used, the reflectance characteristics of the multilayer reflective film become good. Specifically, Ru and Ru-(Nb,Zr,Y,B,Ti,La,Mo) are preferable as materials for the protective film 34. Such a protective film is particularly effective when the absorber film contains a Ta-based material and the absorber film is patterned by dry etching with a Cl-based gas.

[0094] As described above, a conductive film 36 (see FIG. 7) may be formed on the surface of the substrate 10 opposite to the surface in contact with the multilayer reflective film 32 for the purpose of electrostatic chucking. The electrical characteristics (sheet resistance) required for the conductive film 36 are usually 100 Ω / □ or less. The conductive film 36 can be formed by a known method. For example, the conductive film 36 can be formed by magnetron sputtering or ion beam sputtering using a target of a metal such as Cr or Ta or an alloy thereof.

[0095] The above-mentioned underlayer may be formed between the substrate 10 and the multilayer reflective film 32. The underlayer can be formed for the purposes of improving the smoothness of the main surface of the substrate 10, reducing defects, improving the reflectance of the multilayer reflective film 32, reducing stress in the multilayer reflective film 32, and the like.

[0096] The shape data of the front and back surfaces of the substrate 10 may be measured in a state where the multilayer reflective film 32 is formed on the first main surface 12a of the substrate 10, or in a state where the multilayer reflective film 32 and the protective film 34 are formed on the first main surface 12a of the substrate 10. That is, the shape data of the first main surface and the second main surface (rear surface) of the multilayer reflective film-coated substrate may be measured by a surface shape measuring device. In this case, the shape data of the front and rear surfaces of the substrate 10 may be measured in a state where the conductive film 36 is formed on the second main surface 12b. From the shape data obtained by the measurement, the angle α between the least squares plane of the first region and the least squares plane of the third region may be obtained.

[0097] In the multilayer reflective film coated substrate of this embodiment, the angle α between the least square plane of the first region and the least square plane of the third region may be less than 1.2°. Moreover, the angle α is preferably less than 1.0°, and more preferably less than 0.8°.

[0098] That is, the present invention may have the following aspects. A multilayer reflective film-coated substrate having a substantially rectangular planar shape and a size of 152 mm×152 mm, comprising a first main surface on which a transfer pattern is formed, and a second main surface facing the first main surface and on which a mask stage of an exposure tool is electrostatically chucked, wherein a multilayer reflective film that reflects EUV light and a protective film that protects the multilayer reflective film are formed in this order on the first main surface, and a conductive film for electrostatic chuck is formed on the second main surface, the first main surface includes a first region located toward the center and a second region located outside the first region; the second main surface includes a third region located toward the center and a fourth region located outside the third region, a least squares plane of the first region and a least squares plane of the third region form an angle α of less than 1.2°.

[0099] The method for manufacturing a substrate with a multilayer reflective film of this embodiment preferably includes the steps of forming a multilayer reflective film on a first main surface of a mask blank substrate, measuring the surface shape of the first main surface on which the multilayer reflective film is formed to obtain shape data of the first main surface, calculating shape data of the second main surface using thickness data of the substrate, determining least-squares planes of the first region and the third region from the shape data of the first main surface and the second main surface, respectively, and selecting a substrate with a multilayer reflective film in which the angle α between the least-squares plane of the first region and the least-squares plane of the third region is less than 1.2°.

[0100] Alternatively, a conductive film may be formed on the second main surface of the selected multilayer reflective film-coated substrate to produce a conductive film-coated substrate. A reflective mask blank may be produced by forming an absorber film to be a transfer pattern on the multilayer reflective film or protective film of the selected multilayer reflective film-coated substrate.

[0101] [Reflective mask blank] Next, the reflective mask blank of this embodiment will be described. FIG. 7 is a schematic diagram showing a reflective mask blank 40 of this embodiment. The reflective mask blank 40 of this embodiment has a configuration in which an absorber film 42 serving as a transfer pattern is formed on the protective film 34 of the multilayer reflective film-coated substrate 30 described above.

[0102] The material of the absorber film 42 is not particularly limited as long as it has a function of absorbing EUV light. For example, it is preferable to use Ta (tantalum) alone or a material mainly composed of Ta. The material mainly composed of Ta is, for example, a Ta alloy. Alternatively, examples of the material mainly composed of Ta include a material containing Ta and B, a material containing Ta and N, a material containing Ta and B and further containing at least one of O and N, a material containing Ta and Si, a material containing Ta, Si and N, a material containing Ta and Ge, and a material containing Ta, Ge and N.

[0103] The reflective mask blank of this embodiment is not limited to the configuration shown in Fig. 7. For example, a resist film serving as a mask for patterning the absorber film 42 may be formed on the absorber film 42. The resist film formed on the absorber film 42 may be a positive type or a negative type. In addition, the resist film formed on the absorber film 42 may be for electron beam writing or for laser writing. Furthermore, a hard mask (etching mask) film may be formed between the absorber film 42 and the resist film.

[0104] The shape data of the front and back surfaces may be measured in a state where the absorber film 42 is formed on the multilayer reflective film 32, or in a state where the absorber film 42 and the hard mask film are formed on the multilayer reflective film 32. That is, the shape data of the first main surface and the second main surface (rear surface) of the reflective mask blank may be measured by a surface shape measuring device. In this case, the shape data of the front and rear surfaces of the substrate 10 may be measured in a state where the conductive film 36 is formed on the second main surface 12b. From the shape data obtained by the measurement, the angle α between the least squares plane of the first region and the least squares plane of the third region may be obtained.

[0105] In the reflective mask blank of this embodiment, the angle α between the least squares plane of the first region and the least squares plane of the third region may be less than 1.2°. Moreover, the angle α is preferably less than 1.0°, and more preferably less than 0.8°.

[0106] That is, the present invention may have the following aspects. A reflective mask blank having a substantially rectangular planar shape and a size of 152 mm×152 mm, comprising a first main surface on which a transfer pattern is formed, and a second main surface facing the first main surface and on which a mask stage of an exposure tool is electrostatically chucked, wherein a multilayer reflective film that reflects EUV light, a protective film that protects the multilayer reflective film, and an absorber film that absorbs EUV light are formed in this order on the first main surface, and a conductive film for electrostatic chuck is formed on the second main surface, the first main surface includes a first region located toward the center and a second region located outside the first region; the second main surface includes a third region located toward the center and a fourth region located outside the third region, A reflective mask blank, wherein an angle α between a least squares plane of the first region and a least squares plane of the third region is less than 1.2°.

[0107] The method for manufacturing a reflective mask blank of this embodiment preferably includes the steps of forming a multilayer reflective film, a protective film and an absorber film on a first main surface of a mask blank substrate, measuring the surface shape of the first main surface on which the absorber film is formed to obtain shape data of the first main surface, calculating shape data of the second main surface using thickness data of the substrate, determining least-squares planes of the first region and the third region from the shape data of the first main surface and the second main surface, respectively, and selecting a reflective mask blank in which the angle α between the least-squares plane of the first region and the least-squares plane of the third region is less than 1.2°.

[0108] Also, a conductive film 36 may be formed on the second main surface of the selected reflective mask blank.

[0109] [Reflective mask] Next, the reflective mask 50 of this embodiment will be described. FIG. 8 is a schematic diagram showing a reflective mask 50 of this embodiment.

[0110] The reflective mask 50 of this embodiment has an absorber film pattern 52 obtained by patterning the absorber film 42 of the above-mentioned reflective mask blank 40. In the reflective mask 50 of this embodiment, exposure light is absorbed in a portion where the absorber film pattern 52 is present, and exposure light is reflected in a portion where the multilayer reflective film 32 (or protective film 34) is exposed by removing the absorber film 42. As a result, the reflective mask 50 of this embodiment can be used as a reflective mask for lithography using, for example, EUV light as exposure light.

[0111] [Method of manufacturing semiconductor device] A semiconductor device can be manufactured by a lithography process using the above-described reflective mask 50 and an exposure device. Specifically, the absorber of the reflective mask 50 is applied to a resist film formed on a semiconductor substrate. film Pattern 52 is transferred. Thereafter, necessary steps such as a development step and a cleaning step are performed, whereby a semiconductor device having a pattern (circuit pattern, etc.) formed on a semiconductor substrate can be manufactured. EXAMPLES

[0112] [Example] A SiO2-TiO2-based glass substrate with a size of 152 mm x 152 mm and a thickness of 6.4 mm was prepared as a mask blank substrate 10. Using a double-sided polishing machine, the front and back surfaces of the glass substrate were polished stepwise with cerium oxide abrasive grains and colloidal silica abrasive grains. The surface of the glass substrate was then treated with low-concentration hydrofluoric acid. The surface roughness of the obtained glass substrate was measured with an atomic force microscope. As a result, the root-mean-square roughness (Rq) of the surface of the glass substrate was 0.15 nm.

[0113] The shape (surface form, flatness) of the surface of the glass substrate was measured using a surface shape measuring device (UltraFlat200 manufactured by Tropel). The surface shape was measured at 1024×1024 points in a 148 mm×148 mm area excluding the peripheral area of ​​the glass substrate. As a result, the flatness of the surface of the glass substrate was 290 nm (convex shape). The measurement results of the shape (flatness) of the surface of the glass substrate were stored in a computer as height information relative to a certain reference plane for each measurement point. In addition, the thickness data of the glass substrate was used to obtain shape data of the rear surface of the glass substrate. Specifically, the shape data (height data) measured in a certain area of ​​the glass substrate and the thickness data of the glass substrate measured in the same area were used to obtain shape data (height data) of the glass substrate (rear surface) in that area. A laser interferometer was used to measure the thickness data of the glass substrate. The angle α between the reference plane of the front surface of the glass substrate and the reference plane of the rear surface was obtained by calculation. Taking into account the angle α, the height information for each measurement point was compared with the standard value of 20 nm (convex shape) of the surface flatness required for the glass substrate, and the difference (required removal amount) was calculated by computer. Similarly, the height information, including the angle α, was compared with the standard value of 20 nm of the back surface flatness, and the difference (required removal amount) was calculated by computer.

[0114] Next, local surface processing conditions were set for each processing spot area on the surface of the glass substrate according to the required removal amount. A dummy substrate was used in advance, and spot processing was performed on the dummy substrate for a certain period of time without moving the substrate, in the same manner as in actual processing. The shape of the dummy substrate was measured using the same device as that used to measure the above-mentioned front and back surface shapes. The processing volume of the spot per unit time was calculated. Then, the scanning speed for raster scanning the glass substrate was determined according to the required removal amount obtained from the spot information and the information on the surface shape of the glass substrate.

[0115] According to the set processing conditions, a magnetic fluid substrate finishing device (manufactured by QED Technologies) was used to locally process the surface and adjust the surface shape by magnetorheological finishing (MRF) processing so that the flatness of the front and back surfaces of the glass substrate was equal to or less than the above-mentioned standard value. The magnetic fluid used at this time contained iron components. The polishing slurry was an alkaline aqueous solution + abrasive (approximately 2 wt%), and cerium oxide was used as the abrasive. The maximum processing allowance was 150 nm, and the processing time was 30 minutes.

[0116] Thereafter, the glass substrate was immersed in a cleaning tank containing an approximately 10% aqueous hydrochloric acid solution (temperature: approximately 25° C.) for approximately 10 minutes, and then rinsed with pure water and dried with isopropyl alcohol (IPA).

[0117] Next, the front and back surfaces of the glass substrate were subjected to finish polishing under the following conditions. Machining fluid: Alkaline aqueous solution (NaOH) + abrasive (concentration: approx. 2 wt%) Abrasive: colloidal silica, average particle size: approx. 70 nm Polishing platen rotation speed: approx. 1-50 rpm Processing pressure: approx. 0.1 to 10 kPa Polishing time: about 1 to 10 minutes

[0118] Thereafter, the glass substrate was washed with an alkaline aqueous solution (NaOH) to obtain a mask blank substrate 10 for EUV exposure.

[0119] The shape (height) of the first main surface 12a of the obtained mask blank substrate 10 was measured using a surface profiler (NewView6300 manufactured by Zygo). Specifically, the 148 mm×148 mm area of ​​the first main surface 12a was divided into 12 μm×12 μm areas in a grid pattern, and the surface shape was measured for each divided area. Using the shape data obtained by the measurement, a least squares plane of the first area 20a was obtained. In addition, the flatness of the first area 20a was 20 nm.

[0120] Moreover, the shape data of the second main surface 12b (rear surface) was obtained using the shape data of the first main surface 12a and the plate thickness data of the substrate 10. Specifically, the shape data (height data) measured in a certain region of the first main surface 12a and the plate thickness data of the substrate 10 measured in the same region were used to obtain the shape data (height data) of the second main surface 12b (rear surface) in that region. A laser interferometer was used to measure the plate thickness data of the substrate 10. The shape data obtained by the measurement was used to obtain a least squares plane of the third region 20c. Moreover, the flatness of the third region 20c was 22 nm.

[0121] The angle α between the least square plane of the first region 20a and the least square plane of the third region 20c was calculated to be α=0.73°.

[0122] Next, the PV values ​​of the surfaces of the second region 20b and the fourth region 20d of the obtained mask blank substrate 10 were measured using a surface profiler (NewView6300 manufactured by Zygo). The second region 20b and the fourth region 20d were set in the outer regions of the 148 mm x 148 mm region located on the central side. As a result, the PV value of the second region 20b was 302 nm. The PV value of the fourth region 20d was 296 nm.

[0123] Using shape data of the first main surface 12a and the second main surface 12b of the mask blank substrate 10, the shape of the first main surface 12a after the mask blank substrate 10 is attracted to the mask stage of the exposure tool by an electrostatic chuck is obtained by simulation. Specifically, the shape data of the first main surface 12a and the shape data of the second main surface 12b are added together for each measurement region to obtain the shape (height) of the first main surface 12a after the mask blank substrate 10 is attracted to the mask stage of the exposure tool. In addition, the shape data of the first main surface 12a obtained by simulation is used to correct data of a pattern to be drawn on a resist film formed on an absorber film, which will be described later.

[0124] A back surface conductive film made of CrN was formed on the second main surface 12b (back surface) of the mask blank substrate 10 by magnetron sputtering under the following conditions. (Conditions): Cr target, Ar+N2 gas atmosphere (Ar:N2=90%:10%), film composition (Cr:90 atomic %, N:10 atomic %), film thickness 20 nm

[0125] A multilayer reflective film was formed on the first main surface 12a of the mask blank substrate 10 by periodically laminating Mo films / Si films, thereby producing a substrate with a multilayer reflective film.

[0126] Specifically, using a Mo target and a Si target, Mo films and Si films were alternately laminated on a substrate by ion beam sputtering (using Ar). The thickness of the Mo film was 2.8 nm. The thickness of the Si film was 4.2 nm. The thickness of one period of the Mo / Si film was 7.0 nm. Such Mo / Si films were laminated 40 times, and finally a Si film was formed to a thickness of 4.0 nm to form a multilayer reflective film.

[0127] A protective film containing a Ru compound was formed on the multilayer reflective film. Specifically, a RuNb target (Ru: 80 atomic %, Nb: 20 atomic %) was used to form a protective film made of a RuNb film on the multilayer reflective film by DC magnetron sputtering in an Ar gas atmosphere. The thickness of the protective film was 2.5 nm.

[0128] An absorber film was formed on the protective film to produce a reflective mask blank. Specifically, an absorber film consisting of a laminated film of TaBN (film thickness 56 nm) and TaBO (film thickness 14 nm) was formed by DC magnetron sputtering. The TaBN film was formed by reactive sputtering using a TaB target in a mixed gas atmosphere of Ar gas and N2 gas. The TaBO film was formed by reactive sputtering using a TaB target in a mixed gas atmosphere of Ar gas and O2 gas.

[0129] A resist film was formed on the absorber film of the reflective mask blank. A pattern was drawn on the resist film using an electron beam lithography device. The above-mentioned corrected pattern data was used when drawing the pattern. After the pattern was drawn, a predetermined development process was performed to form a resist pattern on the absorber film.

[0130] Using the resist pattern as a mask, a pattern (absorber pattern) was formed in the absorber film. Specifically, the upper TaBO film was dry etched with fluorine gas (CF4 gas), and then the lower TaBN film was dry etched with chlorine gas (Cl2 gas).

[0131] The resist pattern remaining on the absorber film pattern was removed with hot sulfuric acid to produce an EUV reflective mask. Using the produced reflective mask, a lithography process was performed using an exposure device to produce a semiconductor device. Specifically, the absorber pattern of the reflective mask was transferred to a resist film formed on a semiconductor substrate. After that, a semiconductor device with a circuit pattern formed on a semiconductor substrate was produced through necessary processes such as a development process and a cleaning process. The circuit pattern was formed accurately as designed on the semiconductor substrate of the produced semiconductor device.

[0132] [Comparative Example] In the comparative example, a mask blank substrate was produced in the same manner as in the above example, except that the local surface processing treatment in the above example was not carried out.

[0133] In the mask blank substrate manufactured in the comparative example, the angle α between the least squares plane of the first region 20a and the least squares plane of the third region 20c was 1.3°.

[0134] In the mask blank substrate manufactured in the comparative example, the PV value of the surfaces of the second region 20b and the fourth region 20d was 421 nm.

[0135] Using the mask blank substrate manufactured in the comparative example, a substrate with a conductive film, a substrate with a multilayer reflective film, a reflective mask blank, and a reflective mask were manufactured in the same manner as in the above-mentioned example. Using the manufactured reflective mask, a lithography process using an exposure device was performed to manufacture a semiconductor device. Specifically, an absorber pattern of the reflective mask was transferred to a resist film formed on a semiconductor substrate. After that, a semiconductor device having a circuit pattern formed on a semiconductor substrate was manufactured through necessary processes such as a development process and a cleaning process. When the circuit pattern on the manufactured semiconductor substrate was inspected, it was confirmed that the circuit pattern was not formed accurately as designed in some places. [Explanation of symbols]

[0136] 10 Mask blank substrate 12a First main surface 12b Second main surface 20a First Area 20b Second Area 20c Third Region 20d. The Fourth Region 30 Substrate with multilayer reflective film 40 Reflective mask blanks 50 Reflective mask

Claims

1. A mask blank substrate having a substantially rectangular planar shape and a size of 152 mm x 152 mm, a first main surface on which a transfer pattern is formed, and a second main surface opposed to the first main surface and fixed to a mask stage of an exposure apparatus; The first main surface includes a first region located toward the center and a second region located outside the first region, the second main surface includes a third region located toward the center and a fourth region located outside the third region, an angle α between a least square plane of the first region and a least square plane of the third region is less than 1.2°; the PV value of the surface of the second region and the fourth region is 400 nm or less; the PV value of the second region is an absolute value of a numerical value representing a difference in elevation between the highest point and the lowest point of a plane of the second region with respect to a least squares plane of the first region; the PV value of the fourth region is an absolute value of a numerical value representing a difference in elevation between the highest point and the lowest point of a plane of the fourth region with respect to a least squares plane of the third region; the first region is a region in which the transfer pattern is formed, and has a size of 132 mm x 132 mm or more based on the center of the substrate; the third region has a size of 142 mm x 142 mm or more based on the center of the substrate; A mask blank substrate, wherein the second region and the fourth region are regions outside a 148 mm x 148 mm region based on the center of the substrate.

2. The mask blank substrate according to claim 1 , wherein the flatness of the first region is 100 nm or less.

3. The mask blank substrate according to claim 1 , wherein the flatness of the third region is 100 nm or less.

4. The mask blank substrate according to claim 1 , wherein the angle α is less than 0.8°.

5. The mask blank substrate according to claim 1 , wherein the PV value is 310 nm or less.

6. The mask blank substrate according to claim 1 , wherein the mask blank substrate is a reflective mask blank substrate.

7. A substrate with a conductive film, comprising the mask blank substrate according to claim 1 , and a conductive film on a second main surface of the mask blank substrate.

8. A multilayer reflective film-coated substrate comprising a multilayer reflective film formed by alternately laminating high refractive index layers and low refractive index layers on a first main surface of the mask blank substrate according to any one of claims 1 to 7.

9. A reflective mask blank having an absorber film serving as a transfer pattern on the multilayer reflective film of the multilayer reflective film-coated substrate according to claim 8 .

10. A reflective mask having an absorber pattern formed by patterning the absorber film on the multilayer reflective film in the reflective mask blank according to claim 9.

11. 11. A method for manufacturing a semiconductor device, comprising the step of performing a lithography process using an exposure apparatus with the reflective mask according to claim 10 to form a transfer pattern on a transfer recipient.

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