JP6381961B2 - Manufacturing method of mask blank with resist film, manufacturing method of transfer mask, mask blank with resist film, manufacturing method of mask blank, and mask blank - Google Patents

Description

  The present invention relates to a method for manufacturing a mask blank with a resist film, a method for manufacturing a transfer mask, a mask blank with a resist film, a method for manufacturing a mask blank, and a mask blank.

  In recent years, pattern dimensions required for semiconductor elements have been continually miniaturized. Along with this, the pattern size of a transfer mask for manufacturing semiconductor elements is also being miniaturized.

  Since lithography technology is used for pattern formation of the transfer mask, the dimensional accuracy of the resist pattern formed on the mask blank is directly linked to the dimensional accuracy of the pattern shape of the transfer mask. An electron beam exposure apparatus capable of forming a fine pattern is used for resist exposure in the lithography technique. In drawing with an electron beam, in order to obtain a transfer pattern as designed, correction is performed by predicting dimensional variations due to various factors. For example, Patent Document 1 discloses a technique for correcting an electron beam irradiation amount according to the thickness of a resist film.

JP 2011-198922 A

  The demand for the dimensional accuracy of the resist pattern on the mask blank has become more and more severe with the fine structure of semiconductor devices. Specifically, a CD uniformity (Critical Dimension Uniformity: CDU), which is an index of in-plane uniformity of a pattern, is required to be 5 nm or less, more strictly 3 nm or less.

  One method for satisfying this requirement is to keep the resist film thickness constant in the plane, but it is becoming difficult to satisfy the above requirement by itself. As a method for solving such a situation, as described in Patent Document 1, it is conceivable to perform a correction process of the electron beam irradiation amount (exposure amount) according to the film thickness of the resist film. When this method is used, even if the resist film thickness is non-uniform in the plane, the exposure amount of each portion can be set according to the film thickness in each portion in the plane. As a result, it is possible to perform exposure so as to achieve uniform pattern accuracy within the surface of the resist film.

  In Patent Document 1, a parameter (hereinafter also referred to as “resist sensitivity”) indicating how much exposure is necessary to enable pattern formation in a resist film is associated with the film thickness of the resist film. The exposure amount is corrected according to the resist sensitivity.

Here, the present inventors have found the following problems.
Consider a case in which the film thickness distribution in the surface of a resist film is mapped as in Patent Document 1 and used as a resist sensitivity distribution diagram. If a resist sensitivity distribution diagram (hereinafter also referred to as “in-plane sensitivity distribution information”) is obtained, a mask blank is attached to the exposure apparatus, and the exposure amount is corrected in accordance with the in-plane sensitivity distribution information. It should be possible to perform exposure so as to obtain a uniform pattern accuracy in the plane of.

  However, in some cases, there are many mask blanks in a plan view. In that case, it becomes impossible to specify the vertical and horizontal directions in plan view in the mask blank. In this case, the present inventor has noticed that the directionality of the mask blank when the in-plane sensitivity distribution information is obtained may not match the directionality of the mask blank when mounted on the exposure apparatus.

  Conventionally, there is no problem in forming a resist pattern even if the above directivity does not match. In addition, when spin coating is used in the application of the resist solution, the film thickness distribution is basically close to a symmetrical structure if the rotation center and the substrate center match. In that case, even if the above-mentioned directions were not consistent, there was no significant effect.

  However, as described above, in recent years, pattern dimensions required for semiconductor elements have been continually miniaturized. A severe numerical value of CDU of 5 nm or less, more strictly 3 nm or less, is required. When such a strict pattern accuracy is required, the above-described directionality mismatch greatly affects the CDU.

  An object of the present invention is to provide a technique for improving in-plane uniformity of a pattern.

The present inventor has studied a technique for solving the above-described problems. As a result, when obtaining in-plane sensitivity distribution information and mounting the exposure apparatus on an exposure apparatus, it has been found that the mask blank only has to specify the top, bottom, left, and right directions in plan view.
The configuration of the present invention based on this finding is as follows.

<Configuration 1>
The 1st structure of this invention is a manufacturing method of the mask blank with a resist film.
The manufacturing method includes a substrate preparation step of preparing a substrate having a thin film, a resist film forming step of forming a resist film on the surface of the thin film, and a removal step of removing a peripheral portion of the resist film. Yes.
Then, in the removing step, the peripheral edge of the resist film is provided so as to give directionality in plan view when the substrate is placed horizontally by the positional relationship in plan view between the thin film and the resist film. A part is removed.
According to this configuration, the directionality of the mask blank with a resist film when in-plane sensitivity distribution information is obtained and the directionality of the mask blank with a resist film when mounted on the exposure apparatus can be reliably matched. It becomes. As a result, the in-plane uniformity of the pattern can be improved even in a situation where a severe numerical value of CDU of 5 nm or less, more strictly 3 nm or less is required.

<Configuration 2>
According to a second configuration of the present invention, in the configuration described in the first configuration, the substrate has a shape having symmetry in a plan view.
When the substrate has a shape having symmetry in plan view, asymmetry is newly given to the appearance of the substrate in plan view. Then, the effect described in the configuration 1 is further amplified.

<Configuration 3>
A third configuration of the present invention is the configuration described in the first or second aspect, wherein in the removing step, all the peripheral portions in the resist film are removed, while the width of the removal margin at a predetermined peripheral portion is increased. The directionality is imparted by making it larger or smaller than other peripheral portions.
When the resist film is removed at the peripheral portion of the mask blank with the resist film, a metal frame like a frame is formed in plan view. Usually, the resist film and the thin film are completely different in color. Therefore, if the peripheral portion of the upper resist film is largely removed, the operator can easily recognize the directionality. That is, while removing all the peripheral portions in the resist film, the directionality is given by making the width of the removal margin at the predetermined peripheral portion larger or smaller than the other peripheral portions, and the operator can easily change the direction. It becomes possible to recognize sex.

<Configuration 4>
According to a fourth aspect of the present invention, there is provided the structure according to the third aspect, wherein the substrate is a quadrangle in a plan view, and the predetermined peripheral portion is one side of the quadrangle.
In the above case, the resist film can be easily removed using a chemical solution, and the width of the removal margin can be easily adjusted.

<Configuration 5>
The fifth configuration of the present invention is a method for manufacturing a transfer mask.
The manufacturing method includes a substrate preparation step of preparing a substrate having a thin film, an information acquisition step of acquiring in-plane sensitivity distribution information in the resist film, a resist film formation step of forming a resist film on the surface of the thin film, A removal step for removing a peripheral portion of the resist film, an exposure step for exposing the resist film based on the in-plane sensitivity distribution information after the removal step, development after the exposure step, and development on the resist film And a pattern forming step for forming a transfer pattern.
In the removing step, the positional relationship between the thin film and the resist film in the planar view gives the directionality in the planar view when the substrate is horizontally placed in the resist film. Remove the peripheral part. In addition, in the exposure step, the exposure step is performed after matching the directionality given by the removal step with the directionality in the in-plane sensitivity distribution information.
According to this configuration, as described in Configuration 1, the direction of the mask blank with a resist film when the in-plane sensitivity distribution information is obtained and the direction of the mask blank with a resist film when mounted on the exposure apparatus Thus, it is possible to make sure that the characteristics match. As a result, the in-plane uniformity of the pattern can be improved.

<Configuration 6>
The sixth configuration of the present invention is a mask blank with a resist film.
In this configuration, the resist film is provided on the surface of the thin film so as to provide directionality in a plan view when the substrate is placed horizontally by a positional relationship between the thin film and the resist film in a plan view. It is characterized by being formed.
According to this configuration, as described in Configuration 1, the direction of the mask blank with a resist film when the in-plane sensitivity distribution information is obtained and the direction of the mask blank with a resist film when mounted on the exposure apparatus Thus, it is possible to make sure that the characteristics match. As a result, the in-plane uniformity of the pattern can be improved.

<Configuration 7>
The 7th structure of this invention is a manufacturing method of a mask blank provided with the board | substrate which has a thin film.
This manufacturing method is characterized in that marking is performed to give directionality in a plan view when the substrate is placed horizontally on the substrate or the thin film.
According to this configuration, the same effect as described in Configuration 1 can be obtained.

<Configuration 8>
The eighth configuration of the present invention is a method for manufacturing a transfer mask.
The manufacturing method includes a substrate preparation step of preparing a substrate having a thin film, an information acquisition step of acquiring in-plane sensitivity distribution information in the resist film, a resist film formation step of forming a resist film on the surface of the thin film, An exposure process for exposing the resist film based on in-plane sensitivity distribution information, and a pattern forming process for performing development after the exposure process to form a transfer pattern on the resist film are included.
And in the said board | substrate preparatory process, the marking which provides the directionality in planar view at the time of mounting the said board | substrate horizontally with respect to the said board | substrate or the said thin film is performed. In addition, in the exposure step, the exposure step is performed after matching the directionality given to the substrate in the substrate preparation step and the directionality in the in-plane sensitivity distribution information. And
According to this configuration, the same effect as described in Configuration 1 can be obtained.

<Configuration 9>
A ninth configuration of the present invention is a mask blank including a substrate having a thin film.
This configuration is characterized in that an index for providing directionality in a plan view when the substrate is placed horizontally is marked on the substrate or the thin film.
According to this configuration, the same effect as described in Configuration 1 can be obtained.

  ADVANTAGE OF THE INVENTION According to this invention, the technique which improves the in-plane uniformity of a pattern can be provided.

It is process drawing of the cross sectional view of the manufacturing method of the mask blank in this embodiment, the mask blank with a resist film, and the mask for transfer. It is the schematic which shows arrangement | positioning of the mask blank with a resist film and the chemical | medical agent supply nozzle for removal in planar view in the removal process in this embodiment. It is a photograph which shows the result of having performed the optical microscope observation with respect to the mask blank with a resist film in an Example. It is a figure which shows the in-plane sensitivity distribution information in the mask blank with a resist film used in an Example and a comparative example, (a) is a two-dimensional graph, (b) is a three-dimensional graph. It is a figure which shows the in-plane sensitivity distribution information after storing the mask blank with a resist film used in an Example and a comparative example on predetermined conditions, (a) is a two-dimensional graph, (b) is a three-dimensional graph. It is. It is a figure which shows the result of an Example, Comprising: Directionality at the time of obtaining in-plane sensitivity distribution information after storing a mask blank with a resist film under a predetermined condition, and mounting the mask blank with a resist film on an exposure apparatus It is a figure which shows the degree of correction | amendment of exposure amount at the time of making the directionality in the case correspond, (a) is a two-dimensional graph, (b) is a three-dimensional graph. It is a figure which shows the result of a comparative example, Comprising: The directionality at the time of obtaining in-plane sensitivity distribution information in the mask blank with a resist film and the directionality at the time of mounting a mask blank with a resist film on an exposure apparatus are inconsistent It is a figure which shows the degree of the correction | amendment of exposure amount at the time of doing (upside down), (a) is a two-dimensional graph, (b) is a three-dimensional graph. It is a figure which shows the result of a comparative example, Comprising: Directionality at the time of obtaining in-plane sensitivity distribution information after storing a mask blank with a resist film under a predetermined condition, and mounting the mask blank with a resist film on an exposure apparatus It is a figure which shows the degree of correction | amendment of exposure amount at the time of making the directionality at the time disagree (it turned upside down), (a) is a two-dimensional graph, (b) is a three-dimensional graph. .

[Embodiment 1]
Hereinafter, embodiments of the present invention will be described in detail.
In the present embodiment, description will be given in the following order.
1. 1-A) Substrate with Thin Film (Mask Blank) Preparation Step 1-Aa) Substrate Preparation Step 1-Ab) Thin Film Formation Step 1-B) Resist Film Formation Step 1-C) Removal Process 1-D) Information acquisition process 1-E) Exposure process 1-F) Development process 1-G) Etching process 1-H) Others Mask blank with resist film In addition, about the structure which is not described below, you may employ | adopt a well-known structure (For example, Unexamined-Japanese-Patent No. 2013-210576 by this applicant) suitably. In this specification, for example, the contents of Japanese Patent Laid-Open No. 2013-210576 are described with respect to matters having no special mention such as the structure of the thin film.
[Embodiment 1] describes an example in which a device is provided at a position in plan view of a resist film in order to impart directionality.
In [Embodiment 2], an example in which an index for imparting directionality is marked on a thin film or a substrate itself constituting a mask blank will be described.
In [Embodiment 3], other examples will be described.

<1. Manufacturing method of transfer mask>
A method for manufacturing the transfer mask 50 in the present embodiment will be described with reference to FIG. FIG. 1 is a cross-sectional process diagram of a method for manufacturing the mask blank 5, the mask blank 1 with a resist film, and the transfer mask 50 in the present embodiment. In the present embodiment, an example in which the substrate 10 is prepared and the thin film 11 is formed on the substrate 10 in the following 1-A) substrate-preparing step with a thin film is shown, but the thin film 11 is formed in advance. A form in which the mask blank 5 is prepared and a resist film is formed thereon is also included in the form of the present invention.

1-A) Substrate with Thin Film (Mask Blank) Preparation Step 1-A-a) Substrate Preparation Step First, as shown in FIG. 1A, a substrate 10 used for a transfer mask 50 is prepared. As the substrate 10 of the transfer mask 50, a glass substrate can be used. In the case of a transmissive mask, the substrate 10 is selected from a glass material having a high transmittance with respect to exposure light when forming a pattern on the wafer. In the case of a reflective mask, a low thermal expansion glass that can minimize thermal expansion of the substrate 10 due to the energy of exposure light is selected.
Specifically, in the case of a transmission type mask (for example, a binary mask, a phase shift mask, and a gray tone mask), the material of the substrate 10 is synthetic quartz glass, soda lime glass, aluminosilicate glass, borosilicate glass, non-alkali. Glass etc. are mentioned. As a detailed example, a synthetic quartz glass having a high transmittance with respect to light with a wavelength of 300 nm or less is preferably used for the substrate 10 of a transfer mask that uses an ArF excimer laser with a wavelength of 193 nm or a KrF excimer laser with a wavelength of 254 nm as exposure light. be able to.
In the case of an EUV mask which is a reflective mask, the substrate 10 is more preferably within a range of about 0 ± 1.0 × 10 ⁻⁷ / ° C. in order to suppress distortion of the transferred pattern due to heat during exposure. Is preferably a SiO ₂ —TiO ₂ glass, which is a glass material having a low thermal expansion coefficient within a range of about 0 ± 0.3 × 10 ⁻⁷ / ° C.

In the present embodiment, the substrate 10 preferably has a symmetrical shape in plan view. According to the present invention, in a situation where “pattern dimensions required for semiconductor elements are continually miniaturized”, “up, down, left and right directions in a plan view cannot be specified. The directionality of the mask blank 1 with a resist film and the directionality of the mask blank 1 with a resist film at the time of mounting on an exposure apparatus are no longer in agreement with each other. Although details will be described later, in the present embodiment, the positional relationship in plan view between the thin film 11 and the resist film 12 provides directionality in plan view when the substrate 10 is placed horizontally. . In other words, the arrangement of the resist film 12 causes asymmetry to the substrate 10 having a symmetrical shape in plan view provided with the resist film 12.
Therefore, when the substrate 10 has a shape having symmetry in plan view, the appearance in plan view becomes “symmetry → asymmetry”, and the effect of this embodiment is particularly obtained. However, even if the substrate 10 does not have symmetry in the plan view, it is still easy to specify the vertical and horizontal directions in the plan view. Even in such a case, the directionality of the mask blank 1 with a resist film when the in-plane sensitivity distribution information is obtained may be inconsistent with the directionality of the mask blank 1 with a resist film when mounted on the exposure apparatus. Can be reduced. As a result, the effect of the present embodiment that improves the in-plane uniformity of the pattern can be exhibited.

  In addition, it is preferable that the board | substrate 10 is a square by planar view, and a predetermined peripheral part is one side of the said square. Of course, the substrate 10 may have a polygonal shape in a plan view, or may be a circular shape, a circular shape with a part of a straight line, or other symmetric shape or asymmetric shape. 1-C) As will be described later in the removing step, the resist film 12 using a chemical solution can be easily removed, and the width of the removal margin can be easily adjusted. In particular, in the case of a square in plan view, it is a situation where the vertical and horizontal directions cannot be specified at all. By performing the 1-C) removal step in such a situation, it is possible to specify the vertical and horizontal directions.

1-Ab) Thin Film Formation Step Next, as shown in FIG. 1B, the thin film 11 is formed on the main surface of the substrate 10. The thin film 11 formed on the surface of the substrate 10 and under the resist film 12 is the thin film 11 selected according to the use of the transfer mask 50 to be manufactured. If it enumerates, the following (1)-(5) will be mentioned.

(1) Thin film of binary mask When producing a binary mask blank, the thin film 11 which has a light shielding film is formed on the board | substrate 10 which has translucency with respect to the light of exposure wavelength.
This light shielding film is made of a material containing a transition metal alone or a compound thereof such as chromium, tantalum, ruthenium, tungsten, titanium, hafnium, molybdenum, nickel, vanadium, zirconium, niobium, palladium, rhodium. For example, a light-shielding film composed of chromium or a chromium compound in which one or more elements selected from elements such as oxygen, nitrogen, and carbon are added to chromium. Further, for example, a light shielding film composed of a tantalum compound in which one or more elements selected from elements such as oxygen, nitrogen, and boron are added to tantalum.
Further, the thin film 11 has a light-shielding film having a two-layer structure of a light-shielding layer and a front-surface antireflection layer, or a three-layer structure in which a back-surface antireflection layer is added between the light-shielding layer and the substrate 10. is there. Moreover, it is good also as a composition gradient film | membrane from which the composition in the film thickness direction of a light shielding film differs continuously or in steps.
Moreover, it is good also as a structure of the thin film 11 which has an etching mask film | membrane on a light shielding film. This etching mask film has etching selectivity (etching resistance) with respect to etching of the light-shielding film containing transition metal silicide, and in particular, chromium, or a chromium compound in which elements such as oxygen, nitrogen, and carbon are added to chromium. It is preferable to use a material. At this time, the transfer mask 50 may be manufactured with the etching mask film remaining on the light shielding film by providing the etching mask film with an antireflection function.

(2) Thin film of binary mask having other configuration As another example of thin film 11 of binary mask, a light shielding film made of a material containing a compound of transition metal and silicon (including transition metal silicide, particularly molybdenum silicide). The structure which has can also be mentioned.
This light-shielding film is made of a material containing a compound of a transition metal and silicon, and examples thereof include a material mainly composed of these transition metal and silicon and oxygen and / or nitrogen. Examples of the light shielding film include a material mainly composed of a transition metal and oxygen, nitrogen, and / or boron. As the transition metal, molybdenum, tantalum, tungsten, titanium, hafnium, nickel, vanadium, zirconium, niobium, palladium, ruthenium, rhodium, chromium, or the like is applicable.
In particular, when the light shielding film is formed of a molybdenum silicide compound, a two-layer structure of a light shielding layer (MoSi or the like) and a surface antireflection layer (MoSiON or the like), or a back surface reflection between the light shielding layer and the substrate 10. There is a three-layer structure to which a prevention layer (MoSiON or the like) is added.
Moreover, it is good also as a composition gradient film | membrane from which the composition in the film thickness direction of a light shielding film differs continuously or in steps.

(3) Thin film of halftone type phase shift mask When producing a halftone type phase shift mask, transition metal and silicon (transition metal silicide) are formed on a substrate 10 that is transparent to the wavelength of exposure light used during transfer. The thin film 11 having a light semi-transmissive film made of a material containing a compound (including molybdenum silicide in particular) is formed.
The light semi-transmissive film included in the thin film 11 transmits light having an intensity that does not substantially contribute to exposure (for example, 1% to 30% with respect to the exposure wavelength), and has a predetermined phase difference (for example, 180%). Degree). The halftone phase shift mask includes a light semi-transmission part obtained by patterning the light semi-transmission film, and a light transmission part that does not have the light semi-transmission film and that transmits light having an intensity that substantially contributes to exposure. Thus, the phase of the light is transmitted through the light semi-transmissive part and the phase of the light is substantially inverted with respect to the phase of the light transmitted through the light transmissive part. Lights that pass through the vicinity of the boundary part and enter each other's areas due to the diffraction phenomenon cancel each other, so that the light intensity at the boundary part is almost zero, and the contrast of the boundary part, that is, the resolution is improved.
This light semi-transmissive film is made of a material containing a compound of, for example, a transition metal and silicon (including a transition metal silicide), and includes a material mainly composed of these transition metal and silicon, and oxygen and / or nitrogen. . As the transition metal, molybdenum, tantalum, tungsten, titanium, hafnium, nickel, vanadium, zirconium, niobium, palladium, ruthenium, rhodium, chromium, or the like is applicable.
In the case of having a light-shielding film on the light semi-transmissive film, the material of the light semi-transmissive film contains a transition metal and silicon. It is preferable to have chromium (having etching resistance), particularly chromium, or a chromium compound in which elements such as oxygen, nitrogen, and carbon are added to chromium.

(4) Thin film of multi-tone mask The thin film 11 of the multi-tone mask has a laminated structure of one or more semi-transmissive films and a light shielding film.
As for the material of the semi-transmissive film, in addition to the same element as the light semi-transmissive film of the halftone phase shift mask blank, a material containing a simple metal such as chromium, tantalum, titanium, aluminum or an alloy thereof or a compound thereof is also included. .
The composition ratio and film thickness of each element are adjusted so as to have a predetermined transmittance with respect to the exposure light. As the material of the light-shielding film, the light-shielding film of the binary mask blank can be applied, but the composition and film of the light-shielding film material so as to achieve a predetermined light-shielding performance (optical density) in a laminated structure with the semi-transmissive film. The thickness is adjusted.

(5) Thin film of reflective mask In the thin film 11 of the reflective mask, a multilayer reflective film that reflects exposure light is formed on the substrate 10, and an absorber film that absorbs exposure light is formed in a pattern on the multilayer reflective film. Has a structured. Light (EUV light) incident on a reflective mask mounted on an exposure machine (pattern transfer device) is absorbed by a portion having an absorber film and reflected by a multilayer reflective film in a portion having no absorber film. Is transferred onto the semiconductor substrate 10 through the reflection optical system.
The multilayer reflective film is formed by alternately laminating high refractive index layers and low refractive index layers. Examples of the multilayer reflective film include Mo / Si periodic multilayer films, Ru / Si periodic multilayer films, Mo / Be periodic multilayer films, and Mo compound / Si compound periodic multilayer films in which Mo films and Si films are alternately stacked for about 40 periods. Si / Nb periodic multilayer film, Si / Mo / Ru periodic multilayer film, Si / Mo / Ru / Mo periodic multilayer film, Si / Ru / Mo / Ru periodic multilayer film, and the like. The material can be appropriately selected depending on the exposure wavelength.
The absorber film has a function of absorbing exposure light such as EUV light, and for example, tantalum (Ta) alone or a material mainly composed of Ta can be preferably used. Such an absorber film preferably has an amorphous or microcrystalline structure in terms of smoothness and flatness.

1-B) Resist Film Formation Step Next, as illustrated in FIG. 1C, a resist film 12 is formed on the thin film 11 of the mask blank 5. The resist film 12 is formed with a resist solution. A known resist solution may be used. A specific method for forming the resist film 12 may be a known method. For example, the resist blank may be spin-coated on the surface of the mask blank 5 and then baked.

  In this way, the mask blank 1 with a resist film used for manufacturing the transfer mask 50 is manufactured.

1-C) Removal Step In this step, the peripheral portion of the resist film 12 is removed as shown in FIG. More specifically, the peripheral portion of the resist film 12 is removed so as to give directionality when the substrate 10 is placed horizontally depending on the positional relationship between the thin film 11 and the resist film 12 in plan view.
Hereinafter, a specific example of this process will be described with reference to FIG. FIG. 2 is a schematic view showing the arrangement of the mask blank 1 with a resist film and the removal chemical supply nozzle 20 in a plan view in the removing step in the present embodiment. Here, the shape of the substrate 10 in plan view is a square. Further, a removal chemical solution supply nozzle 20 (hereinafter simply referred to as the nozzle 20) provided in the sky direction as viewed from the mask blank 1 with a resist film is represented by a dotted line.

  First, the mask blank 1 with a resist film is placed so that the resist film 12 is positioned in the sky direction and the substrate 10 is positioned in the ground direction. That is, the resist film 12 is placed so that the main surface faces the sky and the back surface of the substrate 10 (the surface opposite to the surface on which the thin film 11 is formed) faces the ground. Then, a plurality of nozzles 20 for supplying a chemical solution for removing the resist film 12 are arranged in the sky direction as viewed from the peripheral portion of the resist film 12. The discharge port of the nozzle 20 faces the peripheral portion of the resist film 12.

  Here, the arrangement of the nozzles 20 is devised in order to give directionality in a plan view when the substrate 10 is placed horizontally by the positional relationship between the thin film 11 and the resist film 12 in a plan view. . More specifically, the nozzle 20 corresponding to one side (also referred to as the upper side) in a reference direction in planar view (although there is no limitation, for example, the upper direction) is arranged closer to the periphery (outside) of the substrate 10. Keep it. In this state, a chemical solution for removing the resist film 12 is discharged from the nozzle 20. By doing so, as shown in FIG. 2, in this embodiment, the peripheral portion of the resist film 12 on one side (also referred to as the upper side) in the reference direction (upward direction) in plan view is changed to the other side. It can be removed smaller than the peripheral portion.

The peripheral portion of the resist film 12 is removed, and the thin film 11 is exposed. The thin film 11 in the present embodiment is made of metal. Therefore, a metal frame like a frame is formed on the peripheral portion of the mask blank 1 with a resist film in plan view. Usually, the resist film 12 and the thin film 11 are different in color. Therefore, when the peripheral portion of the upper resist film 12 is largely removed, the operator can easily recognize the directionality. That is, while removing all the peripheral portions in the resist film 12, the directionality is given by making the width of the removal margin at the predetermined peripheral portions smaller than the other peripheral portions, and the operator can easily apply the directivity. Can be recognized.
Further, in the case where the shape of the substrate 10 in plan view is a quadrangle (particularly a square) as in the present embodiment, the resist film is formed by moving a plurality of nozzles arranged in a row in the center direction or the outward direction of the substrate along the rows The width of the removal margin can be easily changed, and the workability is remarkably improved.

  Here, the directionality is given by reducing the width of the removal margin, but conversely, the directionality can be imparted even if the width of the removal margin is made larger than the other peripheral portions. In that case, the nozzle 20 corresponding to the upper side is arranged near the center of the substrate 10. However, after all, if directionality can be imparted to the mask blank 1 with a resist film, the size of the removal margin of the resist film 12 is not limited, and the shape of the removal margin is not limited. Further, the width of the removal margin of the resist film 12 other than the upper side may be the same or different from each other. After all, if the operator can identify the upper side, there is no restriction on removal.

  Incidentally, when the resist film 12 is formed by applying a resist solution on the thin film 11, the resist film 12 is formed so as to rise at the peripheral portion of the thin film 11. When the mask blank 1 with a resist film is transported, particles from the resist film 12 are generated if other members (members in the apparatus, etc.) come into contact with the raised portion. As described above, CDU is required to be 5 nm or less, more strictly 3 nm or less. In such a situation, the generation of particles significantly reduces the in-plane uniformity. However, it is possible to suppress the generation of particles from the resist film 12 by removing all peripheral portions of the resist film 12 as in the present embodiment. Of course, it is possible to impart directionality by removing a predetermined peripheral portion without removing all the peripheral portions. However, taking into account the reasons for the above particles, it is preferable to remove all peripheral portions of the resist film 12. In addition, it is preferable to make the width of the removal margin at the predetermined peripheral portion larger or smaller than the other peripheral portions.

The process up to this step is the manufacturing method of the mask blank 1 with a resist film. In this step, it becomes possible to impart directionality to the mask blank 1 with a resist film, and as a result, the in-plane uniformity of the pattern can be improved.
The manufacturing method of the transfer mask 50 is obtained by adding the following steps to the steps up to this step. This will be described below.

1-D) Information Acquisition Step & 1-E) Exposure Step As shown in FIG. 1E, the formed resist film 12 is exposed in a predetermined shape. At that time, the resist film 12 is exposed based on the in-plane sensitivity distribution information. The in-plane sensitivity distribution information is information indicating the sensitivity distribution in exposure when the resist film 12 is viewed in plan. This information may be numerical information or visual information such as a resist sensitivity distribution diagram. As a method for obtaining the in-plane sensitivity distribution information, a known method may be used. For example, as described in Patent Document 1, the film thickness distribution in the surface of the resist film 12 may be mapped and used as a resist sensitivity distribution diagram. If the thickness of the resist film 12 is large, the resist film 12 may not react sufficiently even if the resist film 12 is exposed to a predetermined exposure amount. On the other hand, if the thickness of the resist film 12 is small, the resist film 12 reacts sufficiently. A resist sensitivity distribution map is created based on this information. Then, the mask blank 5 is mounted on the exposure apparatus, the exposure amount is corrected according to the in-plane sensitivity distribution information, and exposure is performed so that the pattern accuracy is uniform within the surface of the resist film 12. The 1-D) information acquisition step may be performed before the exposure is actually performed in the 1-E) exposure step.

  As mentioned in the subject of the present invention, there are many mask blanks 5 in some cases in a square shape in plan view. In that case, it is impossible to specify the vertical and horizontal directions in the plan view of the mask blank 5. As a result, the directionality of the mask blank 1 with a resist film when the in-plane sensitivity distribution information is obtained may not match the directionality of the mask blank 1 with a resist film when mounted on the exposure apparatus. However, in this embodiment, directionality is given to the mask blank 1 with a resist film, and the exposure step is performed after matching the directionality given by the removal step with the directionality in the in-plane sensitivity distribution information. Can be performed.

  As a specific exposure method and exposure amount correction method, a known method may be used. For example, electron beam drawing may be used, or the exposure method used for each mask mentioned in 1-Ab) thin film formation step may be adopted.

1-F) Development Step A resist pattern is formed by the development step as shown in FIG. A known method may be used as a specific operation or developer in the development process.

1-G) Etching Step A resist pattern can be formed through the above steps. Using the resist pattern, a predetermined pattern is formed on the thin film 11 under the resist pattern. As shown in FIG. 1G, the thin film 11 is etched using the resist film 12 on which a predetermined resist pattern is formed as a mask. A predetermined transfer pattern is formed on the thin film 11 by etching.

  Note that a known method may be used as the etching method. A preferable example is dry etching using a reactive gas as an etchant in the step of etching the thin film 11. If the resist pattern of this embodiment is used, an accurate transfer pattern can be formed even if the reactive gas contains an isotropic etching gas.

  Further, the composition of the surface layer of the thin film 11 includes chromium, and on the other hand, the reactive gas can be preferably applied to an etching method using a mixed gas containing at least oxygen and chlorine.

1-H) Others As shown in FIG. 1 (h), the transfer mask 50 in this embodiment is manufactured by removing the resist pattern and appropriately performing other processes such as cleaning. These methods may be known ones.
In addition to the above structure, another film may be provided as appropriate. For example, a resist base film may be provided between the thin film 11 and the resist film 12.

<2. Mask blank with resist film 1>
Among the above methods, the mask blank 1 with a resist film manufactured up to the 1-C) removal step has a great feature. The mask blank 1 with a resist film in the present embodiment first includes a substrate 10 having a thin film 11 and a resist film 12 formed on the surface of the thin film 11. In addition, the resist film 12 is formed on the surface of the thin film 11 so as to give directionality when the substrate 10 is placed horizontally by the positional relationship between the thin film 11 and the resist film 12 in plan view. Has been.

  When the resist film 12 is removed at the peripheral portion of the mask blank 1 with resist film, a metal frame like a frame is formed in plan view. Usually, the resist film 12 and the thin film 11 are completely different in color. Therefore, when the peripheral portion of the upper resist film 12 is largely removed, the operator can easily recognize the directionality. That is, while removing all peripheral portions in the resist film 12, the directionality is given by making the width of the removal margin at the predetermined peripheral portion larger or smaller than the other peripheral portions, and the operator can easily It becomes possible to recognize the directionality.

  Thereby, a sensitivity map in which the distribution state of resist sensitivity is fixed can be produced. By creating an exposure condition (for example, electron beam drawing condition) map for dimension correction at the time of drawing based on this sensitivity map, the circumstances of both maps coincide, and the difference between the upper, lower, left, and right at the time of drawing (separate In other words, it is possible to prevent the east-west-north-north difference). As a result, a resist pattern having excellent dimensional accuracy (CDU) can be formed. As a result, the transfer mask 50 having excellent dimensional accuracy can be manufactured.

[Embodiment 2]
In the present embodiment, an example will be described in which an index for providing directionality is marked on the thin film 11 or the substrate 10 itself constituting the mask blank 5. The contents not specifically mentioned below are the same as those in [Embodiment 1].

First, in 1-Aa) substrate preparation step, the substrate 10 or the thin film 11 is marked to give the mask blank 5 the directionality when the mask blank 5 is placed horizontally. The marking here refers to giving a visual target to the mask blank 5. This index is not particularly limited as long as it can provide directionality when the mask blank 5 is placed horizontally. For example, you may perform the process which drops the angle | corner of the intersection part of the upper side when the board | substrate 10 is planarly viewed, and another side, and the target which shows directions, such as an arrow, with respect to the board | substrate 10 or the thin film 11 may be performed. You may mark. The position of this marking may be arbitrary. For example, a visual target may be marked on the end surface of the substrate 10, and the top portion of the intersection between the end surface of the substrate 10 and the main surface is chamfered. A target may be marked on the chamfered surface. When marking a target on the main surface of the substrate 10, the target is marked at a position where it can be visually recognized even after the resist solution is applied. For example, a configuration in which the target mark marked on the peripheral portion of the thin film 11 is exposed by removing all the peripheral portion of the resist film 12 in the 1-C) removing step may be adopted.
Further, 1-D) information acquisition step & 1-E) the exposure step and the subsequent methods may be the same as those in [Embodiment 1].
In the present embodiment, the mask blank 5 itself is also characterized. First, the mask blank 5 includes a substrate 10 having a thin film 11. In addition, the substrate 10 or the thin film 11 is marked with an index for providing directionality when the mask blank 5 is placed horizontally. As a result, a resist pattern having excellent dimensional accuracy (CDU) can be formed. As a result, the transfer mask 50 having excellent dimensional accuracy can be manufactured.

[Embodiment 3]
In this embodiment, other examples will be described.
Although each process was provided in said embodiment, it is as follows when the technical idea of this invention is described simply.
“The resist film is placed on the base so that the directionality when the base is horizontally placed is determined by the positional relationship between the base and the resist film formed on the base in a plan view. A method of manufacturing a mask blank with a resist film to be formed. "
“A method for producing a mask blank with a resist film, characterized in that a marking is applied to a substrate to give directionality when the substrate is placed horizontally.”
Of course, the above contents may be applied to the manufacturing method of the transfer mask 50 or the mask blank 1 with resist film itself.

  The “base” here is a target to which a resist solution is applied, and refers to the substrate 10 having the thin film 11 in the above embodiment. Of course, even when the substrate is understood as the substrate 10 itself and the resist film 12 is applied to the substrate 10, the method described in the above embodiment can be applied. In this case, for example, a case where an imprint mold is produced from the mask blank 5 can be mentioned. Since the imprint mold is a system in which the pattern is transferred by directly pressing the resist film 12 applied on the transfer object, the shape of the fine pattern formed on the surface of the imprint mold is greatly affected.

In particular, in many cases, a master mold serving as a master for producing an imprint mold is formed with a chromium-based thin film 11 or a tantalum-based thin film 11 on the surface of a substrate 10 such as synthetic quartz glass, and a resist film on the surface. 12 is manufactured. In this case, the resist film 12 is patterned by a lithography method, and the lower thin film 11 and the substrate 10 are etched using the resist pattern as a mask to form an uneven pattern of the imprint mold.
That is, even in the case of producing an imprint mold, in-plane uniformity of the pattern is a big problem. In order to improve in-plane uniformity, it is important to obtain in-plane sensitivity distribution information and correct the exposure amount according to the information. Then, as in the method of manufacturing the transfer mask 50, it is important to match the directionality when the in-plane sensitivity distribution information is obtained with the directionality when mounted on the exposure apparatus.
As a result, even when an imprint mold is produced, the above steps are performed, so that the idea of the present invention can be sufficiently applied.

  As described above, according to each of the embodiments described above, a technique for improving the in-plane uniformity of a pattern can be provided.

  Next, an Example is shown and this invention is demonstrated concretely. Of course, the present invention is not limited to the following examples.

<Example>
In this embodiment, “the orientation of the mask blank 1 with resist film when the in-plane sensitivity distribution information is obtained and the mask with resist film when being mounted on the exposure apparatus, which are expected when symmetry is imparted,” The effect of “consistently matching the direction of the blank 1” was verified. Therefore, the process up to immediately before the actual exposure is performed in the 1-E) exposure process. That is, the exposure amount correction result based on the in-plane sensitivity distribution information was examined. If the in-plane uniformity can be kept good in this correction result, the uniformity of the finally obtained pattern can also be kept good. Based on this idea, the exposure amount when the in-plane sensitivity distribution information is obtained and the direction in which the in-plane sensitivity distribution information is attached to the exposure apparatus are matched (Example) and not (Comparative Example). We investigated how the in-plane uniformity of the correction results differed.

1-A) Substrate with Thin Film (Mask Blank) Preparation Step 1-A-a) Substrate Preparation Step Translucent made of synthetic quartz glass having a main surface dimension of about 152 mm × about 152 mm and a thickness of about 6.25 mm The board | substrate 10 (henceforth the translucent board | substrate 10) which has was prepared.

1-Ab) Thin Film Formation Step First, a light semi-transmissive film (lower layer) was formed on the translucent substrate 10.
Using a single-wafer sputtering apparatus on a substrate 10 made of synthetic quartz glass, using a mixed target of molybdenum (Mo) and silicon (Si) (atomic% ratio Mo: Si = 13: 87) as a sputtering target, A MoSiN film (lower layer) with a film thickness of 69 nm was formed by reactive sputtering (DC sputtering) in a mixed gas atmosphere of argon and nitrogen. The transmittance was 6.04% (λ = 193 nm), and the phase difference was 179.5 °.

Next, a light shielding film (upper layer) having a three-layer structure was formed on the light semi-transmissive film.
A single-wafer DC sputtering apparatus using a chromium (Cr) target and a mixed gas of argon (Ar), carbon dioxide (CO ₂ ), nitrogen (N ₂ ), and helium (He) (flow rate ratio: Ar: CO ₂ : N ₂ : He = 22: 39: 6: 33, pressure = 0.2 Pa) as a sputtering gas by reactive sputtering (DC sputtering: DC power 1.9 kW), a chrome-lean CrOCN film having a thickness of 30 nm is formed. did.
Further, using the same chromium (Cr) target, a mixed gas of argon (Ar) and nitrogen (N ₂ ) (flow rate ratio: Ar: N ₂ = 83: 17, pressure = 0.1 Pa) is used as a sputtering gas, and the reaction A CrN film having a thickness of 4 nm was formed by reactive sputtering (DC sputtering: DC power 1.4 kW).
Further, using the same chromium (Cr) target, a mixed gas of argon (Ar), carbon dioxide (CO ₂ ), nitrogen (N ₂ ), and helium (He) (flow rate ratio: Ar: CO ₂ : N ₂ : He = 21: 37: 11: 31, pressure = 0.2 Pa) was used as a sputtering gas to form a chromium-rich CrOCN film with a film thickness of 14 nm by reactive sputtering (DC sputtering: DC power 1.9 kW).
By the above procedure, the light-shielding film 3 of a chromium-based material having a three-layer structure of the lowermost layer made of CrOCN, the lower layer made of CrN, and the upper layer made of CrOCN was formed with a total film thickness of 48 nm from the phase shift film side.
The board | substrate 10 with the thin film 11 was obtained by the above procedure. The optical density when the light semi-transmissive film and the light shielding film were combined was set to 3.0 (λ = 193 nm).

1-B) Resist Film Formation Step First, as a pretreatment, HMDS treatment was performed on the light shielding film, which is the upper layer of the thin film 11, in order to improve adhesion with the resist film 12. Thereafter, a chemically amplified positive resist (PRL009: manufactured by FUJIFILM Electronics Materials) for electron beam drawing was applied to the surface of the thin film 11 by spin coating. Then, the resist film 12 (thickness 120 nm) was formed by heating at 130 ° C. for 600 seconds.

1-C) Removal Step A mask blank 1 with a resist film was placed in the apparatus shown in FIG. Then, a nozzle 20 that discharges a chemical solution for removing the resist film 12 is arranged so that the width of the removal distance of the resist film 12 is reduced on one side (upper side) of the square substrate 10 in plan view. Then, a chemical solution was discharged to remove all peripheral portions of the resist film 12, and the width of the removal margin of the resist film 12 on the upper side was made smaller than the width of the margin of removal on the other sides. This is shown in FIG. FIG. 3 is a photograph showing the result of optical microscope observation of the mask blank 1 with a resist film. As shown in FIG. 3, the width of the removal margin of the resist film 12 is 1.1 mm on the upper side, and the width of the removal margin is 1.5 mm on the other side (for example, the left side).

1-D) Information Acquisition Step First, the in-plane sensitivity distribution information on the resist film 12 is measured by measuring the film thickness of the resist film 12 using a spectral interference type film thickness measuring device (manufactured by Nanometrics) (4.2 inches in the center of the substrate). Visualization was performed by making 441 points (21 points × 21 points) in the corner area. FIG. 4 shows the result of this visualization.
4A and 4B are diagrams showing in-plane sensitivity distribution information in the mask blank 1 with a resist film used in Examples and Comparative Examples. FIG. 4A is a two-dimensional graph and FIG. 4B is a three-dimensional graph.
Incidentally, FIG. 5 is a diagram showing in-plane sensitivity distribution information after storing the mask blank 1 with a resist film used in Examples and Comparative Examples under a predetermined condition, and (a) is a two-dimensional graph. (B) is a three-dimensional graph.

1-E) Exposure Step Next, the exposure amount was corrected based on the in-plane sensitivity distribution information so that the pattern formed on the resist film 12 was uniform using an electron beam lithography apparatus manufactured by Elionix. The result is shown in FIG. FIG. 6 is a diagram showing the results of the example, and the surface after storing the mask blank 1 with a resist film in a casing having an opening that can be opened and closed at the top, and storing it under predetermined conditions (23 ° C., 30 h). It is a figure which shows the degree of correction | amendment of the exposure amount at the time of making the directionality when obtaining internal sensitivity distribution information correspond with the directionality at the time of mounting the mask blank 1 with a resist film in exposure apparatus, a) is a two-dimensional graph, and (b) is a three-dimensional graph.
As can be seen from FIG. 6, the exposure amount is normally corrected. By performing the exposure as it is, the in-plane uniformity of the pattern formed on the resist film 12 can be improved. As a result, it was found that the in-plane uniformity of the pattern formed on the transfer mask 50 and the imprint mold can be improved.

<Comparative example>
In the comparative example, the directionality of the mask blank 1 with a resist film when the in-plane sensitivity distribution information is obtained does not match the directionality of the mask blank 1 with a resist film when mounted on the exposure apparatus (upside down). did. Other than that, it was the same as the example. The result is shown in FIG. FIG. 7 is a diagram showing the result of the comparative example, and the directionality when obtaining the in-plane sensitivity distribution information in the mask blank 1 with resist film, and when the mask blank 1 with resist film is mounted on the exposure apparatus. It is a figure which shows the degree of correction | amendment of the exposure amount at the time of making directionality inconsistent (it turned upside down), (a) is a two-dimensional graph, (b) is a three-dimensional graph.
As can be seen from FIG. 7, the exposure amount is not normally corrected. If exposure is performed in this state, the in-plane uniformity of the pattern formed on the resist film 12 cannot be maintained. As a result, it was found that the in-plane uniformity of the pattern formed on the transfer mask 50 and the imprint mold could not be maintained.

In the comparative example, a similar test was performed on the mask blank 1 with a resist film after being stored under predetermined conditions. The result is shown in FIG. FIG. 8 is a diagram showing the results of the comparative example, and the directionality when obtaining in-plane sensitivity distribution information after storing the mask blank 1 with resist film under predetermined conditions, and the mask blank 1 with resist film Is a diagram showing the degree of correction of the exposure amount when the directionality when attaching to the exposure apparatus is inconsistent (upside down), (a) is a two-dimensional graph, (b) Is a three-dimensional graph.
As can be seen from FIG. 8, the exposure amount is not normally corrected. If exposure is performed in this state, the in-plane uniformity of the pattern formed on the resist film 12 cannot be maintained. As a result, it was found that the in-plane uniformity of the pattern formed on the transfer mask 50 and the imprint mold could not be maintained.

  As a result, in this example, the in-plane uniformity of the pattern could be improved.

1 ... Mask blank with resist film 5 ... Mask blank 10 ... Substrate 11 ... Thin film 12 ... Resist film 20 ... Nozzle 50 ... Transfer mask

Claims (7)

A method for producing a mask blank with a resist film,
It has a thin film, a substrate preparation step of preparing the substrate is rectangular in plan view,
A resist film forming step of forming a resist film on the surface of the thin film;
A removal step of removing all of the rectangular peripheral portion of the resist film;
Is included,
Said removing step, the positional relationship in a plan view between the thin film and the resist film, so as to impart directionality in a plan view at the time of placing the substrate horizontally, the rectangle in the resist film resist of being removed in a width of three sides white same removal of the peripheral portion, and wherein the remaining one side is a step of removing a large or small amount of removal than the other three sides <br/> Manufacturing method of mask blank with film.   The method for manufacturing a mask blank with a resist film according to claim 1, wherein the substrate has a shape having symmetry in a plan view. 3. The resist film according to claim 1, wherein the removing step is a step of removing the remaining one side of the peripheral edge portion of the square in the resist film with a smaller removal amount than the other three sides. Of manufacturing mask blanks. What manufacturing method der the transfer mask using a resist Makuzuke mask blank manufactured by the method for producing a resist Makuzuke mask blank according to any one of claims 1 to 3,
An information acquisition step of acquiring in-plane sensitivity distribution information in the resist film of the mask blank with the resist film,
After the removing step, an exposure step for exposing the resist film based on the in-plane sensitivity distribution information;
After the exposure step, development is performed and a pattern forming step of forming a transfer pattern to the resist film,
The exposure process, in terms of the resist Makuzuke was coincident with the direction in the plane sensitivity distribution information and directions that are granted to the mask blank, a transcription and performs exposure of the resist film Mask manufacturing method. Have a thin, a resist film with a mask blank comprising a substrate which is square in plan view, and a resist film formed on the surface of the thin film,
The resist film has all of the square periphery removed,
Of the peripheral edge portions of the quadrilateral in the resist film so as to give directionality in the plan view when the substrate is placed horizontally by the positional relationship in plan view between the thin film and the resist film A mask blank with a resist film , wherein the three sides are removed with the same removal margin width, and the remaining one side is removed with a removal amount larger or smaller than the other three sides . The mask blank with a resist film according to claim 5, wherein the remaining one side of the peripheral edge portion of the square in the resist film is removed with a smaller removal amount than the other three sides. A method for producing a transfer mask using the mask blank with a resist film according to claim 5,
An information acquisition step of acquiring in-plane sensitivity distribution information in the resist film of the mask blank with the resist film,
After the removing step, an exposure step for exposing the resist film based on the in-plane sensitivity distribution information;
After the exposure step, development is performed, and a pattern formation step of forming a transfer pattern on the resist film,
In the exposure step, the resist film is exposed after aligning the directionality given to the mask blank with resist film and the directionality in the in-plane sensitivity distribution information. Mask manufacturing method.