JP6509987B2 - Reflective mask blank and method of manufacturing the same, and reflective mask and method of manufacturing the same - Google Patents

Description

  The present invention relates to a reflective mask blank and a method of manufacturing a reflective mask used for manufacturing a semiconductor device or the like, and a method of manufacturing a mask blank and a mask.

 In general, in the process of manufacturing a semiconductor device, formation of a fine pattern is performed using a photolithography method. In addition, a transfer mask usually called several photomasks is used to form this fine pattern. In general, this transfer mask is a translucent glass substrate provided with a fine pattern made of a metal thin film or the like, and the photolithography method is also used in the production of this transfer mask.

 In the production of a transfer mask by photolithography, a mask blank having a thin film (for example, a light shielding film) for forming a transfer pattern (mask pattern) on a light transmitting substrate such as a glass substrate is used. In the manufacture of a transfer mask using this mask blank, a drawing process for drawing a desired pattern on a resist film formed on the mask blank, and after drawing, the resist film is developed to form a desired resist pattern. A developing step to be formed, 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 are performed. In the development step, a desired pattern is drawn on a resist film formed on a mask blank, and then a developer is supplied to dissolve a portion of the resist film soluble in the developer to form a resist pattern. . Further, in the etching step, using the resist pattern as a mask, the exposed portion of the thin film where the resist pattern is not formed is removed by dry etching or wet etching, whereby a desired mask pattern is formed on the light transmitting substrate. Form. Thus, the transfer mask is completed.

  Further, as a type of transfer mask, in addition to a binary mask having a light shielding film pattern made of a chromium-based material on a conventional light transmitting substrate, a phase shift type mask is known. The phase shift mask has a structure having a phase shift film on a light transmitting substrate. The phase shift film has a predetermined phase difference, and for example, a material containing a molybdenum silicide compound is used. . In addition, a binary mask using a material containing a metal silicide compound such as molybdenum as a light shielding film has come to be used.

  In recent years, in the semiconductor industry, along with the high integration of semiconductor devices, fine patterns which exceed the transfer limit of conventional photolithography using ultraviolet light are required. In order to enable such fine pattern formation, EUV lithography, which is an exposure technique using Extreme Ultra Violet (hereinafter referred to as “EUV”) light, is considered promising. Here, EUV light refers to light in a wavelength band of soft x-ray region or vacuum ultraviolet light region, and specifically, light having a wavelength of about 0.2 to 100 nm. A reflective mask has been proposed as a mask used in this EUV lithography. 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 in a pattern on the multilayer reflective film.

As described above, with the increasing demand for miniaturization in the lithography process, the problems in the lithography process are becoming remarkable. One of them is a problem regarding defect information of a mask blank substrate or the like used in the lithography process.
Conventionally, in a blank inspection or the like, the position of the defect of the substrate is specified by the distance from the position with the substrate center as the origin (0, 0). For this reason, the positional accuracy is low, and there is variation in detection among devices. Even in the case of patterning on a thin film for pattern formation avoiding a defect when drawing a pattern, it is difficult to avoid in the order of μm. For this reason, the defect is avoided by changing the direction in which the pattern is transferred or shifting the transfer position roughly in the order of mm.

Under such circumstances, for the purpose of enhancing the inspection accuracy of the defect position, for example, it has been proposed to form a reference mark on a mask blank substrate and specify the position of the defect as a reference position.
In Patent Document 1, the size of a sphere equivalent diameter of 30 to 30 on the film-forming surface of a reflective mask blank substrate for EUV lithography can be specified so that the position of a minute defect of about 30 nm in sphere equivalent diameter can be accurately identified. It is disclosed to form at least three marks of 100 nm.

International Publication 2008/129914

  It is theoretically possible to increase the inspection accuracy of the defect position of the mask blank by the method disclosed in Patent Document 1 above. However, in order to form a reference mark on a mask blank substrate or the like and manage the relative position of the reference mark and the defect with high accuracy (coordinate management), the reference mark can be easily detected, in other words, detected reliably. It is required that the variation of the defect detection position based on the reference mark be small.

  Also, recently, based on defect data of the mask blank and device pattern data, an attempt is made to reduce the defect by correcting the drawing data so that the absorber pattern is formed at the location where the defect is present (Defect mitigation technology) has been proposed. In order to realize the above-mentioned technique, an electron beam drawing machine is used in the state of a mask blank with a resist film in which an absorber film is formed on a multilayer reflective film and a resist film for forming an absorber pattern is further formed. Even in the above, the reference mark is detected by the electron beam, and the electron beam drawing is performed based on the corrected / corrected drawing data based on the detected reference point, but the reference mark also has a sufficient contrast for the electron beam scanning. Need to be obtained.

  However, since a resist film is generally formed on substantially the entire surface of the mask blank, damage to the resist by the scanning of the electron beam and the inspection light and the inspection accuracy due to the photosensitivity of the resist may be deteriorated. In addition, on the resist, charge up by the electron beam occurs, which may deteriorate the detection accuracy of the reference mark. In any case, the coordinate management of the defect position based on the reference mark formed on the mask blank, the reference mark detected by the electron beam, and the electronic based on the corrected / corrected drawing data based on the detected reference point There is a problem that it is not possible to reduce defects accurately by performing line drawing.

  Therefore, the present invention has been made in view of such conventional problems, and the purpose thereof is, first, that the electron beam and the inspection light scan the resist film at the time of detection of the reference mark. The object of the present invention is to provide a reflective mask blank and a mask blank in which a reference mark for performing defect coordinate management with high accuracy is provided by solving problems such as charge-up and unnecessary resist sensitization and the like. It is an object of the present invention to provide a method of manufacturing a reflective mask and a mask with reduced defects using a mask blank.

  In order to solve the above problems, the present inventors focused attention on the formation area of the reference mark in particular, and as a result, studied as a result, by forming the resist film on the mask blank while avoiding the formation area of the reference mark, the reference mark At the time of detection, problems such as charge-up caused by scanning the resist film with an electron beam or inspection light, unnecessary resist sensitization, etc. are eliminated, and as a result, the reference mark It can be detected reliably, and moreover the deviation of the reference point of the defect position determined by the scanning of the electron beam and the defect inspection light can be reduced, and the variation of the defect detection position inspected based on the reference mark is small (for example, 100 nm or less) ) Found that it is possible to suppress.

The present inventors have completed the present invention as a result of further intensive research based on the above elucidation facts.
That is, in order to solve the above-mentioned subject, the present invention has the following composition.
(Configuration 1)
A reflective mask blank having a multilayer reflective film for reflecting EUV light and an absorber film for absorbing EUV light formed on a substrate, wherein a resist film for electron beam lithography is formed on the absorber film. And a reference mark serving as a reference of a defect position in defect information is formed on the reflective mask blank, and the resist film is not formed on a region including the formation position of the reference mark. Reflective mask blank.

  As in the configuration 1, in the reflective mask blank of the present invention, a multilayer reflective film that reflects EUV light and an absorber film that absorbs EUV light are formed on a substrate, and an electron is formed on the absorber film. A resist film for line writing is formed, a reference mark serving as a reference of a defect position in defect information is formed on the reflective mask blank, and the resist film is formed on a region including the formation position of the reference mark. It is assumed that the configuration is not formed. Therefore, at the time of detection of the reference mark, the electron beam and the inspection light scan on the absorber film and scan on the resist film can solve problems such as charge-up and unnecessary resist sensitization. As a result, the reference mark can be reliably detected by any of the electron beam drawing machine and the defect inspection apparatus, and furthermore, the deviation of the reference point of the defect position determined by the scanning of the electron beam and the defect inspection light can be reduced. It is possible to reduce (for example, 100 nm or less) variation in defect detection positions inspected based on the marks.

(Configuration 2)
The reference mark has a main mark for determining a reference point of the defect position, and the main mark has a shape of point symmetry and is 200 nm in the scanning direction of the electron beam or the defect inspection light The reflective mask blank according to Configuration 1, having a portion with a width of 10 μm or more.
As in configuration 2, this fiducial mark has a main mark for determining the fiducial point of the defect position. The main mark preferably has a point-symmetrical shape and a portion with a width of 200 nm or more and 10 μm or less in the scanning direction of the electron beam or the defect inspection light. The reference mark configured in this manner can be easily detected by any of an electron beam drawing machine, an optical or EUV light, and a defect inspection device for an electron beam, in other words, it can be detected reliably. Moreover, since the shape is point-symmetrical, the deviation of the reference point determined by the scanning of the electron beam and the defect inspection light can be reduced. Further, the size of the fiducial mark can be further reduced by forming the fiducial mark with the edge basis or forming the fiducial mark at an arbitrary position and specifying the fiducial mark formation position with the coordinate measuring device, In that case, it is possible to make the reference mark only the main mark. If the size of the fiducial mark can be reduced as described above, the processing time can be shortened and the detection time of the fiducial mark can be shortened if, for example, FIB (focused ion beam) is used as the fiducial mark forming means. Therefore, the variation in the defect detection position inspected based on the reference mark is small. Further, as a result, in defect inspection, it is possible to determine the reference point of the defect position and acquire accurate defect information (defect map) including the information of the defect position (the relative position of the reference point and the defect). Furthermore, in the manufacture of a mask, it is compared with drawing data (mask pattern data) designed in advance based on the defect information, and the drawing data is corrected (corrected) with high accuracy so that the influence of defects is reduced. As a result, defects can be reduced in the finally manufactured reflective mask.

(Configuration 3)
The reference mark is composed of a main mark for determining the reference point of the defect position and an auxiliary mark arranged around the main mark, and the main mark has a shape of point symmetry, and The reflective mask blank according to Configuration 1, having a portion with a width of 200 nm to 10 μm in the scanning direction of the electron beam or the defect inspection light.
As in configuration 3, this reference mark is composed of a main mark for determining the reference point of the defect position, and an auxiliary mark arranged around the main mark, and the main mark is point symmetric It is preferable to have a portion having a width of 200 nm or more and 10 μm or less with respect to the scanning direction of the electron beam or the defect inspection light. The reference mark configured in this manner can be easily detected by any of an electron beam drawing machine, an optical or EUV light, and a defect inspection device for an electron beam, in other words, it can be detected reliably. Moreover, since the shape is point-symmetrical, the deviation of the reference point determined by the scanning of the electron beam and the defect inspection light can be reduced. Therefore, the variation in the defect detection position inspected based on the reference mark is small. As a result, in defect inspection, it is possible to determine the reference point of the defect position and obtain accurate defect information (defect map) including the information on the defect position (the reference point and the relative position of the defect). Furthermore, in the manufacture of a mask, it is compared with drawing data (mask pattern data) designed in advance based on the defect information, and the drawing data is corrected (corrected) with high accuracy so that the influence of defects is reduced. As a result, defects can be reduced in the finally manufactured reflective mask.

(Configuration 4)
The resist film is formed in a region including a pattern formation region on which the transfer pattern is formed on the absorber film, and the reference mark is formed in an outer peripheral portion provided outside the pattern formation region. 4. The reflective mask blank according to any one of the configurations 1 to 3, characterized in that
As described in Configuration 4, the reference mark is formed in the non-pattern formation area which is an outer peripheral portion provided outside the pattern formation area in which the transfer pattern is formed. Therefore, in addition to the effects obtained by the configurations 1 to 3 described above, it is possible to minimize the irradiation of the pattern formation region where the transfer pattern is formed by the electron beam and the inspection light when detecting the reference mark. It is possible to provide a high-precision reflective mask without problems such as up and unnecessary resist exposure.

(Configuration 5)
5. The reflective mask blank according to any one of the configurations 1 to 4, wherein the reference mark is formed on the multilayer reflective film.
By forming the reference mark on the multilayer reflective film as in Configuration 5, the reference mark can be easily detected by scanning with the electron beam and the defect inspection light also in the defect inspection after forming the multilayer reflective film. In addition, it is possible to peel off the multilayer reflective film and recycle (reuse) the glass substrate without discarding the multilayer reflective film coated substrate where defects that can not be avoided even by correction or correction of drawing data are found. is there.

(Configuration 6)
In any one of the configurations 1 to 5, the resist film is not formed on a region in a range of 0.5 mm to 5 mm from the outer peripheral edge in the peripheral portion of the reflective mask blank having a size of 6 inches square. Reflective mask blank described in.
As in the sixth configuration, for example, in a reflective mask blank having a size of 6 inches square, a reference mark is formed on a region ranging from 0.5 mm to 5 mm from the outer peripheral edge, and the resist film is formed on this region Is preferably not formed.

(Configuration 7)
A step of forming a resist pattern by electron beam lithography and development using the reflective mask blank according to any one of constitutions 1 to 6, a step of patterning the absorber film using the formed resist pattern as a mask, and A method of manufacturing a reflective mask, comprising: an inspection step using a defect inspection apparatus.
The reflective mask obtained by using the reflective mask blank of the above-described configuration can be obtained by reducing defects by correction / correction of drawing data with high accuracy based on defect information in the reflective mask blank and pattern writing. .

(Configuration 8)
A mask blank in which a thin film to be a transfer pattern is formed on a substrate, a resist film for electron beam drawing is formed on the thin film, and a reference as a reference of a defect position in defect information on the mask blank. A mark is formed, The said resist film is not formed on the area | region containing the formation location of the said reference mark, The mask blank characterized by the above-mentioned.
As in constitution 8, in the mask blank of the present invention, a resist film for electron beam drawing is formed on a thin film to be a transfer pattern, and on this mask blank, a reference mark as a reference of a defect position in defect information The resist film is not formed on the region including the formation portion of the reference mark. Therefore, as in the above configuration 1, when the reference mark is detected, the electron beam and the inspection light scan the absorber film and scan the resist film so that problems such as charge-up and unnecessary resist sensitization can be eliminated. . As a result, the reference mark can be reliably detected by any of the electron beam drawing machine and the optical or electron beam defect inspection apparatus, and the deviation of the reference point of the defect position determined by the scanning of the electron beam and the defect inspection light is small. It is possible to reduce (for example, 100 nm or less) variation in defect detection positions inspected based on the reference marks.

(Configuration 9)
The reference mark has a main mark for determining a reference point of the defect position, and the main mark has a shape of point symmetry and is 200 nm in the scanning direction of the electron beam or the defect inspection light 9. The mask blank according to configuration 8, having a portion with a width of 10 μm or more.
As in arrangement 9, this fiducial mark has a main mark for determining the fiducial point of the defect position. The main mark preferably has a point-symmetrical shape and a portion with a width of 200 nm or more and 10 μm or less in the scanning direction of the electron beam or the defect inspection light. The reference mark configured in this manner can be easily detected by any of an electron beam drawing machine, an optical type, and an electron beam defect inspection apparatus, in other words, it can be reliably detected. Moreover, since the shape is point-symmetrical, the deviation of the reference point determined by the scanning of the electron beam and the defect inspection light can be reduced. Further, the size of the fiducial mark can be further reduced by forming the fiducial mark with the edge basis or forming the fiducial mark at an arbitrary position and specifying the fiducial mark formation position with the coordinate measuring device, In that case, it is possible to make the reference mark only the main mark. If the size of the fiducial mark can be reduced as described above, the processing time can be shortened and the detection time of the fiducial mark can be shortened if, for example, FIB (focused ion beam) is used as the fiducial mark forming means. Therefore, the variation in the defect detection position inspected based on the reference mark is small. Further, as a result, in defect inspection, it is possible to determine the reference point of the defect position and acquire accurate defect information (defect map) including the information of the defect position (the relative position of the reference point and the defect). Furthermore, in the manufacture of a mask, it is compared with drawing data (mask pattern data) designed in advance based on the defect information, and the drawing data is corrected (corrected) with high accuracy so that the influence of defects is reduced. As a result, defects can be reduced in the finally manufactured mask.

(Configuration 10)
The reference mark is composed of a main mark for determining the reference point of the defect position and an auxiliary mark arranged around the main mark, and the main mark has a shape of point symmetry, and The mask blank according to Configuration 8, having a portion with a width of 200 nm or more and 10 μm or less in the scanning direction of the electron beam or the defect inspection light.
Also in the mask blank of the above-described configuration 10, the reference mark configured in this way can be easily detected by any of an electron beam drawing machine, an optical type, and an electron beam defect inspection apparatus, in other words, it can be reliably detected. . Moreover, since the shape is point-symmetrical, the deviation of the reference point determined by the scanning of the electron beam and the defect inspection light can be reduced. Therefore, the variation in the defect detection position inspected based on the reference mark is small. As a result, in defect inspection, it is possible to determine the reference point of the defect position and obtain accurate defect information (defect map) including the information on the defect position (the reference point and the relative position of the defect). Furthermore, in the manufacture of a mask, it is compared with drawing data (mask pattern data) designed in advance based on the defect information, and the drawing data is corrected (corrected) with high accuracy so that the influence of defects is reduced. As a result, defects can be reduced in the finally manufactured mask.

(Configuration 11)
A process of forming a resist pattern by electron beam lithography and development using the mask blank according to any one of configurations 8 to 10, a process of patterning the thin film using the formed resist pattern as a mask, and an inspection process using a defect inspection apparatus And manufacturing the mask.
(Configuration 12)
The method of manufacturing a mask according to configuration 11, wherein the electron beam drawing is performed based on drawing data corrected by detecting a reference mark by an electron beam in an electron beam drawing machine and correcting based on the detected reference point.
The mask obtained by using the mask blank of the above-mentioned configuration can be obtained by reducing defects by correction / correction of drawing data with high accuracy based on defect information in the mask blank and pattern writing.

According to the present invention, at the time of detection of a reference mark, problems such as charge-up due to scanning of the resist film with an electron beam or inspection light, unnecessary resist sensitization and the like are eliminated. As a result, an electron beam drawing machine, defects It can be detected reliably by any inspection device, and moreover the deviation of the reference point of the defect position determined by the scanning of the electron beam and defect inspection light is small, and the coordinate management of the defect (relative position management of reference mark and defect) It is possible to provide a reflective mask blank and a mask blank that can be performed with high accuracy.
Further, according to the present invention, there is provided a reflective mask and a mask in which defects are reduced by performing correction of drawing data and electron beam drawing using the correction data based on the defect information using these mask blanks. be able to.

It is a top view which shows the structure of the reflection type mask blank of this invention. It is a figure which shows the example of a shape of a reference mark. It is a figure which shows the shape example and arrangement | positioning example of the main mark which comprises the reference | standard mark suitable for this invention, and an auxiliary mark. It is a figure for demonstrating the method to determine the reference point using the reference | standard mark suitable for this invention. It is a figure which shows the other example of a shape of a main mark. It is a figure which shows the example of another shape of an auxiliary mark. It is a figure for demonstrating an example of the detection method of an auxiliary mark. It is sectional drawing of the board | substrate with a multilayer reflective film used for the reflective mask blank which concerns on this invention. (A), (b), (c) is sectional drawing of the reflection type mask blank which concerns on this invention. 1 is a cross-sectional view of a binary mask blank according to the present invention. It is sectional drawing of the reflection type mask which concerns on this invention. It is sectional drawing of the binary mask which concerns on this invention. It is a top view which shows the example of another arrangement | positioning of the reference mark in this invention. It is a top view which shows the example of another arrangement | positioning of the reference mark in this invention.

Hereinafter, embodiments of the present invention will be described in detail.
[Reflective mask blank]
The reflective mask blank according to the present invention is a reflective mask blank in which a multilayer reflective film that reflects EUV light and an absorber film that absorbs EUV light are formed on a substrate as described in Configuration 1 above. A resist film for electron beam lithography is formed on the absorber film, and a reference mark serving as a reference of a defect position in defect information is formed on the reflective mask blank, and the formation position of the reference mark is It is characterized in that the resist film is not formed on the region including the film.
The film configuration of the reflective mask blank according to the present invention may be any configuration having a multilayer reflective film that reflects at least EUV and an absorber film that absorbs EUV light on a substrate. (Capping layer, buffer layer) The etching mask film formed on the absorber film may be included.

FIG. 1 is a plan view showing the configuration of a reflective mask blank of the present invention. FIG. 9 is a cross-sectional view thereof.
In FIG. 1, two types of marks, a rough alignment mark 12 of relatively large size and a reference mark (hereinafter referred to as "reference mark of the present invention") 13 according to the present invention which is a small fine mark are formed. There is. As shown in FIG. 9, in the present embodiment, the reference mark 13 is formed in a concave shape in the multilayer reflective film 31 of the reflective mask blank 10.

  Although the rough alignment mark 12 itself does not have a role of a reference mark, it has a role for making it easy to detect the position of the reference mark 13. The reference mark 13 has a small size, and it is difficult to visually indicate a position. Further, if it is attempted to detect the fiducial mark 13 from the beginning with the inspection light or the electron beam, it takes a long time for detection, which is not preferable in the manufacturing process. By providing the rough alignment mark 12 whose positional relationship with the reference mark 13 is predetermined, detection of the reference mark 13 can be performed quickly and easily.

  FIG. 1 shows an example in which the rough alignment marks 12 are arranged at three places near the corners on the main surface of the rectangular glass substrate 11 and the reference marks 13 are arranged two places near each rough alignment mark 12. ing. Both the rough alignment mark 12 and the reference mark 13 are formed on the area indicated by A of the outer peripheral portion on the main surface of the mask blank (non-transfer pattern forming area located outside the pattern forming area where the transfer pattern is formed) It is done. The characteristic configuration of the reflective mask blank of the present invention is that the resist film 61 for electron beam lithography is not formed on the region including the formation portion of the reference mark 13. That is, the resist film 61 is an area excluding the area including the formation area of the reference mark 13 while avoiding the formation area of the reference mark 13 (an area indicated by B in FIG. (This is a region that includes).

  By forming the configuration in which the resist film 61 is not formed on the region including the formation portion of the reference mark 13, the electron beam and the inspection light scan the absorber film when the reference mark is detected. Therefore, problems such as charge-up due to scanning on the resist film and unnecessary resist sensitization can be avoided. As a result, the reference mark can be reliably detected by any of the electron beam drawing machine and the optical defect inspection apparatus, and the detection accuracy of the reference mark is improved, and the defect position determined by the scanning of the electron beam and the defect inspection light The deviation of the reference point can be reduced, and the variation in the defect detection position inspected based on the reference mark can be reduced (for example, to 100 nm or less).

For example, in the case of a reflection type mask blank having a size of 6 inches square, the reference mark 13 is formed on an area in the range of 0.5 mm to 5.0 mm from the outer peripheral edge in view of the width of the chamfer and the pattern transfer area. Preferably, the resist film 61 is not formed on this region.
However, if there is a possibility that the flatness of the main surface may not be very good if it is too close to the outer edge of the substrate, or it may intersect with other types of recognition marks, the region inside 1.0 mm from the outer edge Preferably, the reference mark 13 is formed on the That is, it is desirable to form the reference mark 13 in a region of 1.0 mm to 5.0 mm from the outer peripheral end.

In the present invention, the number of reference marks and rough alignment marks is not particularly limited. At least three fiducial marks are required, but three or more fiducial marks may be used. In addition, it is desirable that the rough alignment mark 12 be formed on the area including the location where the reference mark 13 is formed. The rough alignment mark 12 may not be provided unless there is a particular inconvenience in detecting the reference mark 13 of the present invention from the beginning with the inspection light or the electron beam.
That is, as shown in FIG. 13, for example, the above-described reference marks 13 may be arranged at four places near the corners on the main surface of the glass substrate 11 without providing the rough alignment marks 12. . As a result, the step of forming relatively large rough alignment marks can be omitted, and the processing time of the reference marks can be significantly reduced. FIG. 13 shows, as an example, a reference mark 13 composed of a main mark (described later) 13a and four auxiliary marks (described later) 13b, 13c, 13d and 13e arranged around the main mark 13a.

  Further, as shown in FIG. 1, in the present embodiment, the resist film 61 is formed over the entire periphery of the region including the formation portion of the reference mark 13 in the outer peripheral portion of the reflective mask blank 10. Although not shown, the present invention is not limited to this. For example, the resist film 61 may not be formed in the region where the reference mark 13 is formed and in the vicinity thereof. That is, in the reflective mask blank of the present invention, the resist film 61 may be formed in the above-mentioned pattern formation region and the non-transfer pattern formation region in the outer peripheral portion, but at least when detecting the reference mark It is also possible to adopt a configuration in which the resist film 61 for electron beam drawing is not formed around the formation portion of the reference mark 13 where the inspection light is scanned. However, as in the present embodiment, the resist film 61 is not formed over the entire circumference of the region including the formation portion of the reference mark 13, whereby the resist film is peeled off at the peripheral portion of the substrate. There is also an effect that dusting can be suppressed.

Here, the configuration of the reference mark will be described in more detail.
FIG. 2 is a view showing an example of the shape of the reference mark.
In the example shown in FIG. 2, both the rough alignment mark 12 and the reference mark 13 have a cross shape. The size and width of these marks, the depth of the concave shape, and the like can be arbitrarily set as long as they can be recognized with respect to the electron beam at the time of electron beam drawing and the inspection light of the defect inspection apparatus. As a specific example, in the case of the rough alignment mark 12, the size x1 in the x direction and the size y1 in the y direction (see FIG. 2) are both 0.55 mm, and the line width of the cross shape is 5 μm and the depth In the case of the reference mark 13, the size x2 in the x direction and the size y2 in the y direction (see FIG. 2) are both 0.1 mm, the line width of the cross shape is 5 .mu.m, and the depth is 100 nm. be able to. The distance x3 in the x direction and the distance y3 in the y direction (see FIG. 2) between the center point of the rough alignment mark 12 and the center point of the reference mark 13 can be 1.5 mm.

FIG. 3 is a view showing an example of the shape and arrangement of main marks and auxiliary marks constituting a reference mark particularly suitable for the present invention according to another configuration example of the reference mark, and FIG. It is a figure for demonstrating the method to determine the reference point using a mark.
The reference mark serves as the reference of the defect position in the defect information, but the reference mark 13 of the present invention shown in FIG. 3 is a main mark for determining the position (reference point) as the reference of the defect position. And an auxiliary mark disposed around the main mark.
In FIG. 3 and FIG. 4, a reference mark 13 composed of the main mark 13a and two auxiliary marks 13b and 13c arranged around the main mark 13a is shown as an example.

  In the present invention, the main mark 13a has a polygonal shape having at least two sets of sides perpendicular to and parallel to the scanning direction (X direction and Y direction in FIG. 4) of an electron beam drawing machine or defect inspection light. Is preferred. As described above, since the main mark 13a has a polygonal shape having at least two pairs of sides perpendicular and parallel to the scanning direction of the electron beam or defect inspection light, detection by the electron beam drawing machine and the defect inspection device (Certainty) can be improved, and variations in defect detection positions can be further suppressed. FIGS. 3 and 4 show, as a specific example, the case where the main mark 13a is a square having the same length and width (X and Y directions). In this case, the length in the vertical and horizontal directions can be set to 30 nm to 10 μm, and in particular, 200 nm or more and 10 μm or less is preferable.

  The main mark 13a preferably has a point-symmetrical shape. For example, the shape is not limited to the above-mentioned square, as shown in FIG. 5 (a), the corner of the square may be rounded, as shown in FIG. 5 (b), the shape of octagon, or FIG. As in), it may be in the shape of a cross. Also in this case, the size (longitudinal and lateral length) L of the main mark 13a can be set to 30 nm to 10 μm, and in particular, preferably set to 200 nm or more and 10 μm or less. As a specific example, when the main mark 13a has a cross shape, the size (longitudinal and lateral lengths) can be 5 μm or more and 10 μm or less. Further, although not shown, the main mark 13a may be a regular circle having a diameter of 30 nm or more and 10 μm or less.

  The two auxiliary marks 13b and 13c are disposed around the main mark 13a along the scanning direction (X direction and Y direction in FIG. 4) of the electron beam or the defect inspection light. In the present invention, it is preferable that the auxiliary marks 13b and 13c have a rectangular shape having a short side parallel to a long side perpendicular to the scanning direction of the electron beam or the defect inspection light. Since the auxiliary mark has a rectangular shape having a short side parallel to the long side perpendicular to the scanning direction of the electron beam or the defect inspection light, it can be reliably detected by the scanning of the electron beam drawing machine or the defect inspection device The position of the main mark can be easily identified. In this case, it is desirable that the long side be a length that can be detected by the least possible number of scans of the electron beam drawing machine and the defect inspection apparatus. For example, it is desirable to have a length of 25 μm or more and 600 μm or less. On the other hand, if the length of the long side is short, for example, less than 25 μm, there is a possibility that the auxiliary mark can not be detected easily by scanning with an electron beam drawing machine or defect inspection device. If the length of the long side is longer, for example, more than 600 μm, it is not preferable because the processing time may exceed 1 hour / location depending on the method of forming the reference mark. More preferably, the length of the long side is 25 μm to 400 μm, more preferably 25 μm to 200 μm.

  Further, the auxiliary marks 13b and 13c and the main mark 13a may be separated by a predetermined distance, or may not be separated. When the auxiliary mark and the main mark are separated, the distance is not particularly limited, but in the present invention, for example, the range of about 25 μm to 50 μm is preferable.

  It is desirable that the main mark 13a and the auxiliary marks 13b and 13c have a concave shape in cross section and be a reference mark that can be recognized by providing a desired depth in the height direction of the reference mark. From the viewpoint of improving detection accuracy by electron beam and defect inspection light, it is preferable that the cross-sectional shape is formed so as to spread from the bottom of the concave shape toward the surface side, and the inclination angle of the side wall of the reference mark in this case is It is preferable that it is 75 degrees or more. More preferably, it is desirable that the angle be 80 ° or more, and further preferably 85 ° or more.

The reference point serving as the reference of the defect position is determined as follows using the above reference mark (
See Figure 4).
The position of the main mark 13a can be roughly identified by scanning the auxiliary marks 13b and 13c with an electron beam or defect inspection light in the X and Y directions and detecting these auxiliary marks. After an electron beam or inspection light scans in the X direction and Y direction on the main mark 13a whose position is specified, an intersection point P on the main mark 13a (detected by scanning the auxiliary mark) (usually, the main mark Determine the reference point with the approximate center of

As described above, in the present invention, it is preferable that the main mark 13a has a point-symmetrical shape and a portion with a width of 200 nm to 10 μm with respect to the scanning direction of the electron beam or defect inspection light. It is.
As a result of examining the relationship between the width of the main mark 13a and the contrast to the electron beam, and the relationship between the width of the main mark 13a and the variation of the defect detection position, the inventor finds that the width of the main mark 13a is less than 200 nm. It has been found that the contrast tends to decrease. When the EB contrast decreases, it becomes difficult to detect the main mark in the EB (electron beam) scanning, so that it becomes difficult to correct and correct the drawing data with high accuracy. In addition, it has been found that when the width of the main mark 13a exceeds 10 μm, the variation in defect detection position becomes large (for example, exceeds 100 nm). This can not satisfy the variation of 100 nm or less of the defect detection position when the reference mark for realizing and enabling the aforementioned defect mitigation technology is used as the reference point. Therefore, in order to satisfy both the contrast and the variation in defect detection position, the main mark 13a preferably has a portion with a width of 200 nm to 10 μm with respect to the scanning direction of the electron beam or defect inspection light.

  By the way, as described above, it is preferable that the auxiliary marks 13b and 13c have a rectangular shape having a short side parallel to the long side perpendicular to the scanning direction of the electron beam or the defect inspection light. It is preferable that the side has a length that can be detected by the minimum number of scans of the electron beam drawing machine and the defect inspection apparatus as much as possible, for example, a length of 25 μm or more and 600 μm or less. However, for example, when forming a length of about several hundreds of μm with a focused ion beam, processing time is required for a long time.

  Therefore, the auxiliary mark can be divided into several rectangles as shown in FIG. FIG. 7 is an example specifically showing such an aspect, and a rectangular auxiliary mark 13b1 having a size of 50 μm × 1 μm is provided on one of the 5 μm × 5 μm main marks 13a (Y direction). 13b6 are equally spaced, and the spacing (space) between each auxiliary mark is 50 μm.

In this case, for example, the auxiliary mark is removed in the first scan (first scan), and the auxiliary mark is removed in the second scan (second scan) shifted 60 μm upward (Y direction), and further shifted 60 μm upward The auxiliary mark 13b5 can be detected by the third scan (third scan).
Thus, even if the auxiliary marks are divided and the length of the long side of each divided auxiliary mark is shortened, it is possible to determine the scanning rule and reliably detect the auxiliary marks with as few scans as possible. is there. Further, by dividing the auxiliary marks in this manner, the overall processing time can be shortened.

  Further, in the present invention, as shown in FIG. 14, for example, the above-mentioned main marks 13a are arranged at four places in the vicinity of the corners on the main surface of the glass substrate 11 without providing the above-mentioned auxiliary marks 13b and 13c. You may do so. By this, the process of forming the auxiliary mark can be omitted, and the processing time of the reference mark can be significantly shortened. When it comprises only the main mark 13a as a reference mark, detection becomes difficult by the scanning of the electron beam or defect inspection light by an electron beam drawing machine or a defect inspection apparatus. In that case, the reference mark is formed at a predetermined position from the origin set based on the edge coordinates of the glass substrate 11, and the multilayer reflective film coated substrate or the reflective mask blank on which the reference mark is formed, and formation position information of the reference mark And the reference mark can be reliably detected in a short time. Further, after forming the reference mark, the formation position of the reference mark is specified by the coordinate measuring device, and the multilayer reflective film coated substrate or the reflective mask on which the reference mark is formed is associated with the formation position information of the reference mark. By storing, it is possible to reliably detect the reference mark in a short time.

  The position at which the reference mark 13 of the present invention is formed is not particularly limited. For example, in the case of a reflective mask blank, it may be formed at any position as long as it is a film formation surface of a multilayer reflective film. For example, it may be any position of a substrate, an underlayer (described later), a multilayer reflective film, a protective film (capping layer, buffer layer), and an absorber film.

  In the case of a reflective mask that uses EUV light as exposure light, defects present in a multilayer reflective film or a protective film (capping layer) which is particularly a reflective surface can hardly be corrected, and on the transfer pattern. In order to reduce a critical phase defect, defect information on a multilayer reflective film or a protective film (capping layer) is important in order to reduce transfer pattern defects. Therefore, it is desirable to perform defect inspection at least after forming a multilayer reflective film and after forming a protective film (capping layer) to acquire defect information. For that purpose, it is preferable to form the reference mark of the present invention at least on the multilayer reflective film 31 as shown in FIG.

  The method of forming the fiducial mark 13 of the present invention is not particularly limited. For example, when the cross-sectional shape of the reference mark described above is a concave shape, it may be formed by photolithography method, recess formation by laser light or ion beam, processing mark by scanning a diamond needle, indentation by a microindenter, indentation by imprint method It can be formed.

  In the embodiment shown in FIGS. 3 to 7, two auxiliary marks 13b and 13c are provided around the main mark 13a along the scanning direction (X direction, Y direction) of the electron beam drawing machine or the defect inspection apparatus. Although the present invention has been described with respect to an example in which the above is arranged, the present invention is not limited to such an embodiment. For example, in a method in which the detection of a defect is not based on the scanning of the inspection light, the arrangement position of the auxiliary mark with respect to the main mark is arbitrary as long as the positional relationship between the main mark and the auxiliary mark is specified. Further, in this case, not the center of the main mark but the edge may be used as a reference point.

FIG. 8 shows the structure of a multilayer reflective film coated substrate 50 used for manufacturing the reflective mask blank of the present invention, and the multilayer reflective film 31 of the present invention for reflecting EUV light formed on a glass substrate 11 is shown. A reference mark 13 is formed.
Although FIG. 8 shows an example in which the reference mark 13 is formed by removing all the layers constituting the multilayer reflective film 31, a part of the film constituting the multilayer reflective film 31 is removed and the reference marks 13 are formed. May be formed.

Although FIG. 8 illustrates the multilayer reflective film coated substrate 50 in which the reference mark 13 of the present invention is formed on the multilayer reflective film 31, a protective film in which a protective film 32 (capping layer) is formed on the multilayer reflective film 31. The reference mark 13 of the present invention may be provided to the attached multilayer reflective film coated substrate. In this case, a part or all of the layers constituting the protective film 32 and the multilayer reflective film 31 are removed to form the reference mark 13. The material can be appropriately selected in consideration of the material of the protective film 32, the method of forming the reference mark 13, and the cleaning method after the formation of the reference mark 13.
For example, when the protective film 32 is formed by photolithography using a Ru-based material, it is preferable to form the reference mark 13 on the multilayer reflective film 31 from the viewpoint of processing speed and the like.

When the reference mark is formed by a focused ion beam, carbon (C) may adhere to the surface layer as a product, so it is resistant to a cleaning solution (acid or alkali) for removing the product. Multilayer reflective film 31 (surface layer is Si film) A reference mark 13 is formed on the surface, or a protective film 32 made of a Ru alloy in which another metal (for example, Nb, Zr, B, Ti, etc.) is added to Ru. It is preferable to form the reference mark 13 on the multilayer reflective film coated substrate on which is formed.
The multilayer reflective film 31 is a multilayer film in which low refractive index layers and high refractive index layers are alternately stacked, and in general, a thin film of a heavy element or its compound and a thin film of a light element or its compound A multilayer film in which 40 to 60 cycles are alternately stacked is used.

  For example, as a multilayer reflective film for EUV light with a wavelength of 13 to 14 nm, a Mo / Si periodic laminated film in which Mo films and Si films are alternately laminated for about 40 cycles is preferably used. Besides, as a multilayer reflective film used in the region of EUV light, Ru / Si periodic multilayer film, Mo / Be periodic multilayer film, Mo compound / Si compound periodic multilayer film, Si / Nb periodic multilayer film, Si / Mo / There are Ru periodic multilayer film, Si / Mo / Ru / Mo periodic multilayer film, Si / Ru / Mo / Ru periodic multilayer film, and the like. The material may be appropriately selected depending on the exposure wavelength.

In the case of EUV exposure, the glass substrate 11 has a range of 0 ± 1.0 × 10 ⁻⁷ / ° C., more preferably 0 ± 0.3 × 10, to prevent distortion of the pattern due to heat during exposure. A material having a low thermal expansion coefficient within the range of ^-7 / ° C is preferably used, and as a material having a low thermal expansion coefficient within this range, for example, using SiO ₂ -TiO ₂ based glass, multicomponent glass ceramics, etc. Can do.

  The main surface on the side on which the transfer pattern of the glass substrate 11 is formed is processed so as to have high flatness from the viewpoint of obtaining at least pattern transfer accuracy and position accuracy. In the case of EUV exposure, the flatness is preferably 0.1 μm or less in the region of 132 mm × 132 mm on the main surface of the glass substrate 11 on which the transfer pattern is formed or 142 mm × 142 mm, and particularly preferably It is 0.05 μm or less. The main surface on the opposite side to the side on which the transfer pattern is formed is a surface to be electrostatically chucked when it is set in the exposure apparatus, and has a flatness of 1 μm or less, preferably 0. 5 μm or less.

Further, as the glass substrate 11 of the multilayer reflective film coated substrate, as described above, a material having a low thermal expansion coefficient such as SiO ₂ -TiO ₂ -based glass is used, but such a glass material is precisely polished by It is difficult to realize a high smoothness of, for example, 0.1 nm or less in RMS as surface roughness. Therefore, as shown in FIG. 8, in order to reduce the surface roughness of the glass substrate 11 or to reduce defects on the surface of the glass substrate 11, it is preferable to form the base layer 21 on the surface of the glass substrate 11. As a material of such an underlayer 21, it is not necessary to have translucency to exposure light, and it is preferable to select a material which can obtain high smoothness when the underlayer surface is precisely polished and has a good defect quality. Be done. For example, Si or a silicon compound containing Si (for example, SiO ₂ , SiON, etc.) is preferably used because high smoothness can be obtained when precision polishing is performed and defect quality is good. In particular, Si is preferred.

It is preferable that the surface of the base layer 21 be a surface precisely polished so as to have the smoothness required for a mask blank substrate. It is desirable that the surface of the underlayer 21 be precisely polished so as to have a root mean square roughness (RMS) of 0.15 nm or less, particularly preferably 0.1 nm or less. Further, in consideration of the influence on the surface of the multilayer reflective film formed on the underlayer 21, the surface of the underlayer 21 has Rmax / RMS of 2 to 10 in relation to the maximum surface roughness (Rmax). It is desirable that the precision polishing be performed to 2 to 8 in particular.
The film thickness of the underlayer 21 is preferably, for example, in the range of 75 nm to 300 nm.

  FIG. 9A shows a pattern for absorbing the protective film (capping layer) 32 and EUV light on the multilayer reflective film 31 in the multilayer reflective film coated substrate 50 on which the reference marks 13 shown in FIG. 8 are formed as described above. A reflective mask blank in which an absorber film 41 for formation is formed, and further, a resist film 61 for electron beam drawing is formed on the absorber film 41 except the region including the formation portion of the reference mark 13 10 is shown. A back surface conductive film 42 is provided on the side opposite to the side on which the multilayer reflective film and the like of the glass substrate 11 are formed.

In FIG. 9A, a reflective mask blank in which a protective film (capping layer) 32 and an absorber film 41 are formed on the multilayer reflective film 31 in the multilayer reflective film coated substrate 50 on which the reference marks 13 are formed is shown. Although explained, it does not restrict to this. As described above, it may be a reflective mask blank in which the reference mark 13 is formed on the multilayer reflective film coated substrate 50 on which the protective film 32 is formed, and the absorber film 41 is formed thereon (FIG. 9). (B))). Alternatively, as shown in FIG. 9C, it may be a reflective mask blank in which the absorber film 41 and the resist film 61 are not formed in the region where the reference mark 13 is formed.
When the influence on the multilayer reflective film 31 to the etchant (etching gas) at the time of producing the reflective mask 30 using the reflective mask blank 10 is taken into consideration, FIGS.
As in (b), it is desirable that a protective film 32 and an absorber film 41 be formed on the multilayer reflective film 31 in the formation area of the reference mark 13.

  The absorber film 41 has a function of absorbing, for example, EUV light which is exposure light, and for example, a material consisting essentially of tantalum (Ta) or Ta as a main component is preferably used. As a material containing Ta as a main component, 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, Ta And materials containing Si and N, materials containing Ta and Ge, materials containing Ta, Ge and N, and the like are used.

  In general, the protective film 32 and the buffer film are provided between the multilayer reflective film and the absorber film in order to protect the multilayer reflective film at the time of patterning or pattern correction of the absorber film 41. As the material of the protective film, ruthenium and ruthenium compounds containing one or more elements of niobium, zirconium and rhodium in ruthenium are used in addition to silicon, and as the material of the buffer film, mainly the above-mentioned chromium-based materials Is used.

  As described above, in the reflective mask blank according to the present invention, the resist film is not formed on the region (for example, the region A in FIG. 1) including the formation portion of the reference mark. Therefore, as a method of forming a resist film only in the area (area B in FIG. 1) excluding the area including the formation area of the reference mark in order to obtain a mask blank having such a configuration, for example, There is a method of forming a resist film on the entire surface of the blank main surface and then removing the resist film formed in the area including the formation portion of the above-mentioned reference mark in the blank peripheral portion.

  In this case, as a method of removing the resist film formed in the unnecessary area at the blank peripheral portion, for example, the mask blank surface having a resist film formed on the entire main surface is covered with a cover member, and A solvent for dissolving the membrane is supplied to pass the solvent through the solvent flow path provided on the periphery of the cover member, and is left in the area excluding the area including the formation portion of the reference mark of the mask blank to form the reference mark It is possible to apply the method of removing the unnecessary resist film with the solvent by supplying the solvent to the predetermined part while adjusting the supply amount of the solvent and / or the supply device so that the region including the part is removed. (See Patent No. 3607903). In addition, a head having a supply path for supplying a resist stripping solution to an unnecessary resist area, and a discharge path for discharging the stripping solution in which the resist in the unnecessary resist area is dissolved (specifically, the upper and lower sides of the substrate) You may use the removal apparatus provided with the head formed in cross-sectional U-shape so that a main surface peripheral part and an end surface part may be enclosed (for example, refer Unexamined-Japanese-Patent No. 2004-335845). In addition, after a region including the formation position of the reference mark of the mask blank is sealed in advance so that the resist film is not formed, the resist film may be formed by a general spin coating method.

The present invention also provides a method of manufacturing a reflective mask blank according to the following configuration.
(Configuration A)
In the method of manufacturing a reflective mask blank according to any one of the configurations 1 to 6, a step of preparing a multilayer reflective film coated substrate in which a multilayer reflective film for reflecting EUV light is formed on the substrate; A reference mark forming step of forming a reference mark serving as a reference of a defect position in defect information in the multilayer reflective film, and acquiring defect information of the multilayer reflective film-provided substrate with reference to the reference mark And a step of forming an absorber film on the multilayer reflective film, a region including a pattern forming region on which the transfer pattern is formed on the absorber film, and a location where the reference mark is formed. A reflection comprising a resist film forming step of forming a resist film in a region and a resist film removing step of removing the resist film in a region including the formation portion of the reference mark Method of manufacturing a mask blank.

  As in the configuration A, according to the method of manufacturing a reflective mask blank of the present invention, it is possible to provide a reflective mask blank having the effects described in the above-described configuration 1. That is, in the process of manufacturing the reflective mask, when detecting the reference mark, the electron beam and the inspection light scan on the absorber film and scan on the resist film to charge up, unnecessary resist sensitization, etc. It is possible to provide a reflective mask blank that can eliminate the defects.

(Configuration B)
The method of manufacturing a reflective mask blank according to Configuration A, further comprising a reflective mask blank defect information acquiring step of acquiring defect information of the reflective mask blank with reference to the reference mark.
(Configuration C)
The reflective mask blank according to Configuration A or B, including the step of correlating the defect information of the multilayer reflective film coated substrate and / or the defect information of the reflective mask blank with the reflective mask blank. Manufacturing method.
The reflective mask blank obtained by the manufacturing method of configurations B and C is associated with defect information of the multilayer reflective film coated substrate obtained with reference to the reference mark and / or defect information of the reflective mask blank. By using these pieces of defect information, it becomes possible to correct and correct writing data with high accuracy and to draw a pattern, and it is possible to provide a reflective mask with reduced defects.

  As described above, in the reflective mask blank of the present invention, a multilayer reflective film for reflecting EUV light and an absorber film for absorbing EUV light are formed on a substrate, and an electron beam is formed on the absorber film. A resist film for drawing is formed, a reference mark as a reference of a defect position in defect information is formed on the reflective mask blank, and the resist film is formed on a region including the formation position of the reference mark. It has not been configured. Therefore, at the time of detection of the reference mark, the electron beam and the inspection light scan the absorber film, so that problems such as charge-up due to scanning the resist film and unnecessary resist sensitization can be eliminated. As a result, the reference mark can be reliably detected by any of the electron beam drawing machine and the defect inspection apparatus, and the detection accuracy of the reference mark is improved, and the reference point of the defect position determined by the scanning of the electron beam and the defect inspection light Deviation can be reduced, and variation in defect detection position inspected based on the reference mark can be reduced (for example, to 100 nm or less).

  As a result, in defect inspection, it is possible to determine the reference point of the defect position and obtain accurate defect information (defect map) including the information on the defect position (the reference point and the relative position of the defect). Further, in the manufacture of a mask, the drawing data (mask pattern data) designed in advance is checked on the basis of the defect information, and the drawing data is corrected / corrected with high accuracy so that the influence of the defect is reduced. It becomes possible. Then, the reference mark is detected by the electron beam also in the electron beam drawing machine, and the electron beam drawing is performed based on the corrected / corrected drawing data based on the detected reference point. As a result, defects can be reduced in the finally manufactured reflective mask.

[Mask blank]
FIG. 10 shows a binary mask blank 20 in which a light shielding film 51 is formed on a glass substrate 11. The reference mark 13 of the present invention is formed in the light shielding film 51 in a concave shape. The resist film 61 is not formed on the region including the formation portion of the reference mark 13. The method of forming a resist film, the reference mark, and the method of forming the same in the above configuration are the same as in the case of the above-mentioned reflective mask blank.
Although not shown, by providing a phase shift film, or a phase shift film and a light shielding film on the glass substrate 11, a phase shift type mask blank can be obtained. The base layer 21 may be provided on the surface of the glass substrate 11 as necessary.
The light shielding film may be a single layer or a plurality of layers (for example, a laminated structure of a light shielding layer and an antireflective layer). When the light shielding film has a laminated structure of a light shielding layer and an antireflective layer, the light shielding layer may be formed of a plurality of layers. The phase shift film may be a single layer or a plurality of layers.

  As such a mask blank, for example, a binary mask blank provided with a light shielding film made of a material containing chromium (Cr), a light shielding film made of a material containing a transition metal and silicon (Si) Binary mask blank, binary mask blank having a light shielding film formed of a material containing tantalum (Ta), material containing silicon (Si), or material containing a transition metal and silicon (Si) And a phase shift type mask blank provided with a phase shift film.

Examples of the material containing chromium (Cr) include simple chromium and chromium-based materials (CrO, CrN, CrC, CrON, CrCN, CrOC, CrOCN, etc.).
As the material containing tantalum (Ta), besides tantalum alone, a compound of tantalum and another metal element (for example, Hf, Zr etc.), tantalum and at least one of nitrogen, oxygen, carbon and boron Materials containing two elements, specifically, materials containing TaN, TaO, TaC, TaB, TaON, TaCN, TaBN, TaCO, TaBO, TaBC, TaCON, TaBON, TaBCN, TaBCON, etc. may be mentioned.

  As the material containing silicon (Si), a material further containing silicon and at least one of nitrogen, oxygen and carbon, specifically, a nitride, an oxide, a carbide, an oxynitride of silicon, Materials containing carbonates or carbonates are preferred.

  Moreover, as a material containing the above transition metal and silicon (Si), in addition to the material containing the transition metal and silicon, a material further containing at least one element of nitrogen, oxygen and carbon in the transition metal and silicon Can be mentioned. Specifically, materials containing transition metal silicides or nitrides of transition metal silicides, oxides, carbides, oxynitrides, carbonates or carbonates are preferable. As a transition metal, molybdenum, tantalum, tungsten, titanium, chromium, hafnium, nickel, vanadium, zirconium, ruthenium, rhodium, niobium, or the like is applicable. Among these, molybdenum is particularly preferable.

  Also in the above mask blank of the present invention, a resist film for electron beam drawing is formed on the thin film to be a transfer pattern, and on this mask blank, a reference mark as a reference of the defect position in the defect information is formed. The resist film is not formed on the region including the formation portion of the reference mark. Therefore, as in the case of the above-mentioned reflective mask blank, at the time of detection of the reference mark, the electron beam and the inspection light scan on the absorber film, and charge up by scanning the resist film, unnecessary resist sensitization, etc. Can solve the problem of As a result, the reference mark can be reliably detected by any of the electron beam drawing machine and defect inspection apparatus, and the detection accuracy of the reference mark is improved, and the reference point of the defect position determined by the scanning of the electron beam and defect inspection light Deviation can be reduced, and variation in defect detection position inspected based on the reference mark can be reduced (for example, to 100 nm or less).

[mask]
The present invention also provides a reflective mask in which the absorber film in the reflective mask blank of the above configuration is patterned, and a mask in which the thin film is patterned in the mask blank of the above configuration.
FIG. 11 shows a reflective mask 30 provided with an absorber film pattern 41 a in which the absorber film 41 in the reflective mask blank 10 of FIG. 9A is patterned.
12 shows a binary mask 40 provided with a light shielding film pattern 51a in which the light shielding film 51 in the binary mask blank 20 of FIG. 10 is patterned.

  As a method of patterning a thin film such as the above-mentioned absorber film or the above-mentioned light shielding film or the like to be a transfer pattern in a mask blank, photolithography is most preferable. That is, in order to obtain the reflective mask or mask of the present invention, a step of forming a resist pattern by electron beam drawing and development using the above reflective mask blank or mask blank, and using the formed resist pattern as a mask It is preferable that the manufacturing method includes a step of patterning the absorber film or the thin film, and an inspection step using a defect inspection apparatus.

The present invention also provides a method of manufacturing a reflective mask according to the following configuration.
(Configuration D)
Forming a resist pattern by electron beam lithography and development using the reflective mask blank obtained by the method for producing a reflective mask blank according to any one of configurations A, B, and C, and a formed resist A method of manufacturing a reflective mask comprising the steps of: patterning the absorber film using a pattern as a mask; and an inspection step using a defect inspection apparatus.
(Configuration E)
The formation of the resist pattern is collated with mask pattern data designed in advance based on defect information of the multilayer reflective film coated substrate and / or defect information of the reflective mask blank, and drawn by electron beam lithography A method of manufacturing a reflective mask according to Configuration D, comprising the step of correcting drawing data.
(Configuration F)
The electron beam drawing is performed by detecting a reference mark with an electron beam in an electron beam drawing machine, and performing based on drawing data corrected based on the detected reference point, or the structure 7 The manufacturing method of the reflection type mask in any one.

The reflective mask obtained using the reflective mask blank of the above configuration according to the present invention has reduced defects through correction and correction of drawing data with high accuracy based on defect information in the reflective mask blank and pattern writing. The thing is obtained.
In addition, a mask obtained using the mask blank of the above configuration according to the present invention can be obtained with reduced defects by correction / correction of drawing data with high accuracy based on defect information in the mask blank and pattern writing. .

  Although not shown, a thin film to be a transfer pattern is also patterned on a phase shift film or a phase shift type mask blank having a phase shift film and a light shielding film on the mask blank glass substrate described above. Thus, a phase shift mask is obtained.

Hereinafter, the embodiments of the present invention will be more specifically described by way of examples.
Example 1
A SiO ₂ -TiO ₂ -based glass substrate (having a size of about 152 .mu.m) which is polished stepwise with cerium oxide abrasive grains and colloidal silica abrasive grains using a double-side polishing apparatus and the surface of the substrate surface is treated with a low concentration of silicofluoric acid. 4 mm × about 152.4 mm and a thickness of about 6.35 mm) were prepared. The surface roughness of the obtained glass substrate was 0.25 nm in root mean square roughness (RMS) (measured with an atomic force microscope. The measurement area is 1 μm × 1 μm.).

As a result of measuring the surface shape (surface form, flatness) of both front and back sides of this glass substrate with a flatness measuring device (UltraFlat manufactured by Tropopp) (measurement area 148 mm × 148 mm), the flatness of the glass substrate front and back is about 290 nm Met.
Next, local surface processing was performed on the surface of the glass substrate to adjust the surface shape.
When the surface shape (surface form, flatness) and surface roughness of the obtained glass substrate surface were measured, in the measurement area of 142 mm × 142 mm, the flatness of the front and back was 80 nm and was 100 nm or less, which is favorable. there were.

  Next, a B-doped Si target is used, a mixed gas of Ar gas and He gas is used as sputtering gas, a 100 nm Si underlayer is formed by DC magnetron sputtering, and then thermal energy is applied to the Si film. Stress reduction treatment.

After that, in order to maintain the surface shape and reduce the surface roughness, the surface of the Si underlayer was precisely polished using a single-side polishing apparatus.
When the surface shape (surface shape, flatness) and surface roughness of the obtained Si underlayer were measured, they were 80 nm and 100 nm or less in the measurement area of 142 mm × 142 mm, which was good. The surface roughness was extremely good, 0.08 nm as root mean square roughness RMS in the measurement region of 1 μm × 1 μm. Since the smoothness is as extremely high as 0.1 nm or less in RMS, background noise in a high sensitivity defect inspection apparatus is reduced, which is also effective in suppressing false defect detection.
The maximum surface roughness (Rmax) was 0.60 nm and the Rmax / RMS was 7.5 in the measurement region of 1 μm × 1 μm, and the variation of the surface roughness was small and good.

  Next, using an ion beam sputtering apparatus, 40 cycles of Si film (film thickness: 4.2 nm) and Mo film (film thickness: 2.8 nm) are formed one cycle on the Si underlayer, and multilayer reflection is performed. A film (total film thickness 280 nm) was formed to obtain a multilayer reflective film coated substrate.

Next, on the surface of the multilayer reflective film, a reference mark having a concave shape in cross section with the following surface shape was formed at a predetermined position in a region of 2.5 mm inward from the outer peripheral edge. The formation of the reference mark was performed using a focused ion beam. The conditions at this time were an acceleration voltage of 50 kV and a beam current value of 20 pA.
In the present embodiment, as the reference marks, the above-described main marks and auxiliary marks are formed so as to have an arrangement relationship as shown in FIG. The main mark 13a was a rectangle of 5 μm × 5 μm in size, and the depth was 280 nm because all layers constituting the multilayer reflective film were removed. Further, each of the auxiliary marks 13 b and 13 c is a rectangle having a size of 1 μm × 200 μm, and the depth is 280 nm because all layers constituting the multilayer reflective film have been removed. Further, in the present embodiment, the reference marks are formed at three places as shown in FIG.

When the cross-sectional shape of the reference mark is observed by an atomic force microscope (AFM), the inclination angle of the side wall is 85 degrees, and the curvature radius of the ridge portion between the multilayer reflective film surface and the side wall is about 250 nm. there were.
This fiducial mark formed on the multilayer reflective film has a high contrast of 0.025 and can be accurately detected by an electron beam lithography system or blank inspection system, and the variation in defect detection position is 83 nm and 100 nm or less, and is detected with good reproducibility. I confirmed that I could do it.

  Next, the multilayer reflective film surface was subjected to defect inspection with a blanks defect inspection apparatus (Teron 600 series manufactured by KLA-Tencor). In this defect inspection, a reference point is determined with reference to the above-mentioned reference mark, and convex / concave defect position information and defect size information based on the relative position to the determined reference point are acquired, and a defect map is created. . A multilayer reflective film-attached substrate with defect information (defect map) in which the multilayer reflective film-attached substrate is associated with the defect position information and the defect size information is obtained. The reflectivity of the multilayer reflective film surface of the multilayer reflective film coated substrate was evaluated by an EUV reflectometer. As a result, the variation in the surface roughness of the underlayer was suppressed, and the result was as good as 67% ± 0.2%. .

Next, using a DC magnetron sputtering apparatus, laminating a capping layer (film thickness: 2.5 nm) of RuNb, a TaBN film (film thickness: 56 nm) and a TaBO film (film thickness: 14 nm) on the multilayer reflective film An absorber layer composed of a film was formed, and a CrN conductive film (film thickness: 20 nm) was formed on the back surface.
Next, on the surface of the absorber layer, a positive resist film for electron beam lithography was formed to a thickness of 120 nm as a resist film. The resist film was formed by spin coating using a spinner (roll coating apparatus). Next, the resist film formed on the area including the formation portion of the reference mark, that is, the area of 3.0 mm inside from the outer peripheral edge was removed by applying the method described in the aforementioned Japanese Patent No. 3607903. As a result, an EUV reflective mask blank in which the resist film was not formed on the region including the formation portion of the reference mark was obtained.

  About the obtained EUV reflective mask blank, defect inspection was performed with a blank defect inspection apparatus (Teron 600 series manufactured by KLA-Teccor). Similar to the above, the convex / concave defect position information and the defect size information are acquired with reference to the above-mentioned reference mark, and the defect information in which the EUV reflective mask blank, these defect position information, and the defect size information are associated An EUV reflective mask blank is obtained.

Next, an EUV reflective mask was produced using this EUV reflective mask blank with defect information.
First, based on the defect information of the EUV reflective mask blank, it is checked against mask pattern data designed in advance and corrected to mask pattern data that does not affect pattern transfer using an exposure apparatus, or pattern transfer is affected. If it is determined that there is a problem, for example, the pattern is corrected to mask pattern data to which correction pattern data is added so as to hide a defect under the pattern, or for defects that can not be dealt with even by correction pattern data, defect correction after mask production Based on the corrected mask pattern data, a mask pattern is drawn on the resist film described above by an electron beam drawing machine and developed to form a resist pattern. In the present embodiment, since the relative positional relationship between the reference mark and the defect can be managed with high accuracy, the mask pattern data can be corrected with high accuracy. Then, the reference mark was detected by the electron beam also in the electron beam drawing machine, and the electron beam drawing was performed based on the corrected drawing data based on the detected reference point.

Next, using this resist pattern as a mask, the TaBO film is etched away with a fluorine-based gas (CF ₄ gas) and the TaBN film is etched away with a chlorine-based gas (Cl ₂ gas) to form an absorber on the capping layer. A layer pattern was formed.
Further, the resist pattern remaining on the absorber layer pattern was removed with hot sulfuric acid to obtain an EUV reflective mask.

When the obtained EUV reflective mask was inspected by a mask defect inspection apparatus (Teron 600 series manufactured by KLA-Tencor), no convex defect was confirmed on the multilayer reflective film.
When the thus obtained reflective mask is set in an exposure apparatus and pattern transfer is performed on a semiconductor substrate on which a resist film is formed, good pattern transfer can be performed without defects in the transfer pattern caused by the reflective mask. it can.

(Example 2)
Synthetic quartz substrate (size: about 152.4 mm × about 152.4 mm) which is polished in stages with cerium oxide abrasive grains and colloidal silica abrasive grains using a double-side polisher, and the surface is treated with a low concentration of silicofluoric acid , About 6.35 mm thick). The surface roughness of the obtained glass substrate was 0.2 nm in root mean square roughness (RMS). In addition, the flatness of the front and back surfaces of the glass substrate was about 290 nm.

Next, on the glass substrate, a light shielding film composed of a stacked layer of a TaN film and a TaO film was formed as follows.
Using a tantalum (Ta) target as the target, the power of the DC power supply in a mixed gas atmosphere of xenon (Xe) and nitrogen (N ₂ ) (gas pressure 0.076 Pa, gas flow ratio Xe: N ₂ = 11 sccm: 15 sccm) A TaN film is formed to a film thickness of 44.9 nm by reactive sputtering (DC sputtering) at 1.5 kW, and a mixed gas atmosphere of argon (Ar) and oxygen (O ₂ ) is subsequently used using a Ta target. The TaN film and the TaO film are formed by forming a TaO film with a film thickness of 13 nm with a gas pressure of 0.3 Pa and a gas flow ratio Ar: O ₂ = 58 sccm: 32.5 sccm) and the power of the DC power source being 0.7 kW. The light shielding film for ArF excimer laser (wavelength 193nm) which consists of lamination | stacking of these was formed. The optical density of the light shielding film with respect to ArF excimer laser was 3.0, and the surface reflectance was 19.5%.

Next, on the surface of the light shielding film, a reference mark similar to that of Example 1 was formed at a predetermined position in a region of 2.5 mm inward from the outer peripheral edge. The formation of the reference mark was performed using a focused ion beam. The conditions at this time were an acceleration voltage of 50 kV and a beam current value of 20 pA.
When the cross-sectional shape of the reference mark is observed by an atomic force microscope (AFM), the inclination angle of the side wall is 83 degrees and the curvature radius of the ridge portion between the light shielding film surface and the side wall is about 300 nm It had a good cross-sectional shape.
This fiducial mark formed on the light shielding film has high contrast of 0.02 and can be accurately detected by an electron beam lithography system and blank inspection system, and it has been confirmed that variation in defect detection position is 80 nm and can be detected with good reproducibility. .

  Next, on the surface of the light shielding film, as a resist film, the same positive resist film for electron beam drawing as in Example 1 was formed to a thickness of 120 nm. The resist film was formed by spin coating using a spinner (roll coating apparatus). Next, the resist film formed on the area including the formation portion of the reference mark, that is, the area of 3.0 mm inside from the outer peripheral edge was removed by applying the method described in the aforementioned Japanese Patent No. 3607903. As a result, a binary mask blank in which the resist film was not formed on the region including the formation portion of the reference mark was obtained.

  The obtained binary mask blank was subjected to defect inspection with a blank defect inspection device (Teron 600 series manufactured by KLA-Teccor). Based on the above-mentioned reference mark formed on the light shielding film, convex / concave defect position information and defect size information are acquired, and a binary mask blank, these defect position information, and defect information with defect size information are added. I got a binary mask blank.

Next, a binary mask was fabricated using this binary mask blank with defect information.
First, as in the first embodiment, based on the defect information of the binary mask blank, the mask pattern data designed in advance is compared with the mask pattern data, and is corrected to mask pattern data having no influence on pattern transfer using the exposure apparatus. If it is judged that the pattern transfer is affected, the correction pattern data is corrected to the added mask pattern data, or even for the defects that can not be dealt with even by the correction pattern data, a mask that can reduce the load of defect correction after mask production. The pattern data was corrected, and based on the corrected mask pattern data, a mask pattern was drawn and developed on the above-mentioned resist film by an electron beam drawing machine to form a resist pattern. Also in this embodiment, since the relative positional relationship between the reference mark and the defect can be managed with high accuracy, the mask pattern data can be corrected with high accuracy. Then, the reference mark was detected by the electron beam also in the electron beam drawing machine, and the electron beam drawing was performed based on the corrected drawing data based on the detected reference point.

Next, using this resist pattern as a mask, the TaO film was etched away with a fluorine-based gas (CF ₄ gas) and the TaN film was etched away with a chlorine-based gas (Cl ₂ gas) to form a light shielding film pattern.
Further, the resist pattern remaining on the light shielding film pattern was removed with hot sulfuric acid to obtain a binary mask.

When the obtained binary mask was inspected by a mask defect inspection apparatus ((Telon 600 series manufactured by KLA-Tencor), no convex defect was confirmed on the glass substrate.
The binary mask thus obtained was set in an exposure apparatus, and pattern transfer was performed on a semiconductor substrate on which a resist film was formed. As a result, good pattern transfer was performed without any defect in the transfer pattern.

(Example 3)
A substrate with a multilayer reflective film on which a reference mark is formed, a reflective mask blank, a reflection mask, and the like as in Example 1 except that only a main mark of 5 μm × 5 μm in size is used as a reference mark in Example 1 above. The mold mask was produced in order.
When the obtained EUV reflective mask was inspected by a mask defect inspection apparatus (Teron 600 series manufactured by KLA-Tencor), no convex defect was confirmed on the multilayer reflective film.
When the thus obtained reflective mask is set in an exposure apparatus and pattern transfer is performed on a semiconductor substrate on which a resist film is formed, good pattern transfer can be performed without defects in the transfer pattern caused by the reflective mask. it can.

(Comparative example)
A multilayer reflective film coated substrate on which a reference mark is formed in the same manner as in Example 1 except that the resist film formed on the region including the formation portion of the reference mark is not removed in Example 1 above, a reflective mask blank , And a reflective mask were sequentially produced.

  When the obtained EUV reflective mask was inspected by a mask defect inspection apparatus (Teron 600 series manufactured by KLA-Tencor), several tens of convex defects were confirmed on the multilayer reflective film.

  When the cause of several tens of convex defects found on the multilayer reflective film was examined in detail, the resist film was formed also on the reference mark formation location, so when detecting the reference mark, the electron beam and inspection light Causes problems such as charge-up due to scanning on the resist film and unnecessary resist sensitization, which degrades the detection accuracy of the reference mark and is determined by the scanning of the electron beam and defect inspection light It was found that the deviation of the reference point of the defect position became large, and the variation of the defect detection position inspected based on the reference mark became large.

  In all of the above-described embodiments, the reference marks are formed by the focused ion beam. However, the present invention is not limited to this. As described above, the recess can be formed by photolithography, laser light or the like, formation of a trace by scanning with a diamond needle, indentation by a micro-indenter, embossing by an imprint method, or the like.

10 Reflective mask blank 11 Glass substrate 12 Rough alignment mark 13 Reference mark (Fine mark)
13a Main mark 13b, 13c, 13d, 13e Auxiliary mark 20 Binary mask blank 21 Base layer 30 Reflective mask 31 Multilayer reflective film 32 Protective film 40 Binary mask 41 Absorbent film 50 Substrate with multilayer reflective film 51 Light shielding film 61 Resist film

Claims (10)

A reflective mask blank comprising a multilayer reflective film for reflecting EUV light and an absorber film for absorbing EUV light formed on a substrate,
A reference mark serving as a reference of a defect position in defect information is formed on the multilayer reflective film,
A resist film for electron beam lithography is formed on the absorber film,
A reflective mask blank characterized in that the absorber film and the resist film are not formed on a region including the formation portion of the reference mark. The reference mark has a main mark for determining a reference point of the defect position,
The reflection type according to claim 1, wherein the main mark has a point-symmetrical shape and a portion with a width of 200 nm to 10 μm with respect to the scanning direction of the electron beam or the defect inspection light. Mask blank. The resist film is formed in a region including a pattern formation region on which the transfer pattern is formed on the absorber film, and the reference mark is formed in an outer peripheral portion provided outside the pattern formation region. The reflective mask blank according to claim 1 or 2 , characterized in that The reflective mask blank according to any one of claims 1 to 3 , wherein the reference mark is formed by removing a part of a film constituting the multilayer reflective film. The resist film is not formed on a region in the range of 0.5 mm to 5.0 mm from the outer peripheral edge in the peripheral portion of the reflective mask blank having a size of 6 inches square. The reflective mask blank as described in any one of 4 . A manufacturing method of the anti Igata mask blank,
Preparing a multilayer reflective film coated substrate on which a multilayer reflective film for reflecting EUV light is formed on the substrate;
A reference mark forming step of forming a reference mark serving as a reference of a defect position in defect information on the multilayer reflective film;
A multilayer reflective film coated substrate defect information acquiring step of acquiring defect information of the multilayer reflective film coated substrate with reference to the reference mark;
An absorber film forming step of forming an absorber film on the multilayer reflective film;
A resist film forming step of forming a resist film in a region including a pattern formation region where a transfer pattern is to be formed on the absorber film, and a region including a formation location of the reference mark;
And a removing step of removing the resist film and the absorber film in a region including the formation part of the reference mark. The method for manufacturing a reflective mask blank according to claim 6, further comprising a reflective mask blank defect information acquiring step of acquiring defect information of the reflective mask blank with reference to the reference mark. 8. The reflective mask according to claim 6, further comprising a step of correlating defect information of the multilayer reflective film coated substrate and / or defect information of the reflective mask blank with a reflective mask blank. How to make a blank. A reflective mask comprising: an absorber film on which a transfer pattern is formed by patterning the absorber film in the reflective mask blank according to any one of claims 1 to 5. A process of forming a resist pattern by electron beam lithography and development using the reflective mask blank according to any one of claims 1 to 5 , and patterning the absorber film using the formed resist pattern as a mask A method of manufacturing a reflective mask, comprising the steps of:

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