JP6621947B2 - Mask blank with resist film, method for producing the same, and method for producing a transfer mask - Google Patents

Description

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

  In the photomask processing step, a resist film is formed on a photomask blank on which an optical film such as a light-shielding film or a phase shift film is formed, and a resist pattern is formed by electron beam irradiation. Is transferred to the light shielding film or phase shift film by etching.

  Resist pattern formation by electron beam irradiation performed in this processing step must be performed at an extremely accurate position. However, since a resist film that is usually used is an insulator, charge is accumulated in the resist film (charge-up). May happen. Due to the effect of this charge-up, the electron beam irradiated on the surface of the photomask blank is distorted, and the position of the formed resist pattern is slightly shifted, that is, the accuracy of the resist pattern is reduced.

  Various studies have been made on the suppression of charge-up. One example thereof is described in Patent Document 1. As described in [0003] of Patent Document 1, in order to suppress charge-up, a method using a material in which a conductive filler is dispersed in a resin component has been used in the past. However, with this method, the conductive filler is separated and aggregated, and there is a problem in terms of storage stability.

  Although there was a method of using a surfactant in place of the above method, it was highly environmental dependent such that the conductivity changed depending on the environment. In addition, the use of organic solvent-based to water-based materials has also been demanded.

  As a result, the current mainstream is the use of water-soluble conductive polymers to suppress charge-up. An example of the technique is described in Patent Documents 1 and 2. The technique described in Patent Document 2 is a technique of forming a water-soluble organic conductive film on the surface of a resist film.

JP 2002-226721 A JP 2014-9342 A

  However, according to the investigation of the present inventor, for example, when a pattern with a pitch of 50 nm or less is formed, a higher accuracy is required with respect to the position of the resist pattern. There is a current situation that is becoming insufficient. In addition, as described above, no matter how a water-soluble polymer is used, as long as it is an organic compound, the conductivity depends on the environment.

  An object of the present invention is to provide a technique capable of forming a good resist pattern while removing electricity without depending on the environment for charge-up during electron beam irradiation.

In order to solve the above problems, the present inventor has intensively studied. As a result, the inventor forms a conductive film on the resist film with an inorganic material, instead of focusing on the water-soluble conductive polymer (more specifically, the organic conductive film) which is currently mainstream. I came up with the method. This is different from the old technology of using conductive resin dispersed in the resin component in order to suppress charge-up, and the inorganic conductive film itself is provided on the resist film. This is a method conceived by a completely new idea.
The configuration of the present invention based on this finding is as follows.

<Configuration 1>
The first configuration of the present invention is a mask blank with a resist film.
This configuration includes a substrate having a thin film and a resist film formed on the main surface of the thin film.
Then, an inorganic conductive film containing at least one of Mo and W is formed on the resist film.
According to this configuration, first, since the inorganic conductive film containing at least one of Mo and W is provided on the resist film, the conductivity is dramatically higher than that of the organic conductive film. Can be improved. For example, an oxide of Mo (eg, III, IV) or W (IV) has good conductivity. Moreover, since the conductivity is ensured even with an inorganic conductive film of 5 nm or less, it is possible to effectively eliminate the charge of the resist film generated during electron beam irradiation, thereby forming a resist pattern with a dimension of 50 nm or less. It becomes possible to do. This means that the film for suppressing the charge-up can be made thinner than the organic conductive film of Patent Documents 1 and 2. As a result, a fine pattern can be satisfactorily applied to the mask blank. Further, in the case of organic conductivity, the conductivity and the like may change depending on the environment, but the inorganic conductive film is excellent in physical properties such as conductivity.
Further, since a film containing at least one of Mo and W is used, it is relatively easily soluble in water or an alkaline aqueous solution, and the workability is remarkably improved.
Furthermore, when the inorganic conductive film is provided, so-called metal film is packed on the resist film, so that the resist film becomes airtight, and when the inorganic conductive film is provided, the resist film is stored, for example, The resist film is not deteriorated by oxygen or the like present in the atmosphere, and the plastic case used for transportation is not deteriorated by outgas. That is, the inorganic conductive film also serves as a protective film for the resist film.
As described above, based on this configuration, it is possible not only to efficiently perform charge removal with respect to charge-up compared to the case of an organic conductive film, but also to remarkably suppress changes in the quality of the resist film over time. As a result, it is possible to form a good resist pattern while removing electricity without depending on the environment for charge-up during electron beam irradiation.

<Configuration 2>
According to a second configuration of the present invention, in the configuration described in the first configuration, a water-soluble resin film is formed between the resist film and the inorganic conductive film.
Even if the resist film is irradiated with an electron beam through the inorganic conductive film and drawn to form a predetermined pattern, the inorganic conductive film has a low resistance. Less attenuation. On the other hand, since the inorganic conductive film has a very low resistance, there is a possibility that the exposure area may be affected by a wider area than the drawn point. In order to cancel the possibility, a water-soluble resin film is formed between the resist film and the inorganic conductive film. It is a film having a higher resistance than the inorganic conductive film at the stage of being a resin film. By thus forming a relatively high resistance resin film in between, it is possible to effectively suppress sensitivity fluctuations on the resist surface. Moreover, if the resin film is water-soluble, the inorganic conductive film formed on the resin film is surely removed by pre-rinsing or developing with water or an alkaline solution.

<Configuration 3>
According to a third configuration of the present invention, in the configuration described in the second configuration, the water-soluble resin film is an organic conductive film formed of a conductive polymer.
When the water-soluble resin film is composed of a conductive polymer, the inorganic conductive film can be further thinned. Even if the inorganic conductive film is too thin and the film is cut off, the organic conductive film is reserved as a backfill, so that charge removal with respect to charge-up is reliably performed. In addition, an organic conductive film composed of a conductive polymer has higher resistance than an inorganic conductive film, but has an electronic conductivity, so that an electron propagating to a resist film due to charge-up is maintained. The extinction of the beam can be suppressed. As a result, the sensitivity of the resist film is kept at a particularly high level, and a fine pattern can be formed.

<Configuration 4>
The 4th structure of this invention is a structure in any one of the 1st-3rd, Comprising: The film thickness of an inorganic electroconductive film | membrane is 1 nm-10 nm, Preferably it is 2 nm-5 nm.
If the thickness of the inorganic conductive film is 1 nm or more, the formation state of the inorganic conductive film can be kept good, and the charge can be sufficiently removed. Moreover, if it is 10 nm or less, the labor for producing the inorganic conductive film is not so much required, and it is also possible to suppress the risk that the residue when the inorganic conductive film is removed becomes a foreign substance. In addition, the resist film can be favorably irradiated with the electron beam through the inorganic conductive film. When the thickness is 2 nm to 5 nm, the effect becomes more remarkable.

<Configuration 5>
The 5th structure of this invention is a structure in any one of the 1st-4th, Comprising: An inorganic electroconductive film | membrane has Mo as a main component. In particular, the inorganic conductive film preferably contains Mo oxide.
When metal Mo is formed by sputtering, Mo oxide is formed by natural oxidation. Since the Mo oxide has conductivity and the bulk can maintain a metal state, the conductivity sufficient for charge removal can be maintained even when the film thickness is 5 nm or less. In addition, in the case where the surface of the metal Mo has an oxide formed by natural oxidation, it can be easily removed by pre-rinsing with pure water (ion exchange water) or an alkaline solution before development or a developer.

<Configuration 6>
A sixth configuration of the present invention is the configuration according to any one of the first to fourth, and the inorganic conductive film contains W as a main component. In particular, the inorganic conductive film is preferably an oxide layer mainly composed of a WO ₂ structure. Since WO ₂ is a good conductor and is soluble in alkali, it can be easily removed by pure water (deionized water) before development or pre-rinsing with an alkaline solution or an alkaline developer. Therefore, no residue derived from the inorganic conductive film remains on the surface.

<Configuration 7>
A seventh configuration of the present invention is a method for manufacturing a 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 main surface of the thin film;
An inorganic conductive film forming step of forming an inorganic conductive film containing at least one of Mo and W on the resist film;
It is included.
According to this configuration, the same effects as described in Configuration 1 can be obtained.

<Configuration 8>
An eighth configuration of the present invention is the configuration according to seventh, wherein the resist film forming step and the inorganic conductive film forming step are
A water-soluble resin film forming step of forming a water-soluble resin film on the surface of the resist film;
Have
According to this configuration, the same effect as described in Configuration 2 can be obtained.

<Configuration 9>
The ninth structure of the present invention is the structure described in the eighth, wherein the water-soluble resin film is an organic conductive film made of a conductive polymer.
According to this configuration, the same effects as described in Configuration 3 are obtained.

<Configuration 10>
The 10th structure of this invention is a structure in any one of the 7th-9th, Comprising: An inorganic electroconductive film formation process is performed using sputtering film-forming.
By using a target of molybdenum oxide or tungsten oxide having a desired oxygen content in advance, an inorganic conductive film having a desired degree of oxidation can be formed.

<Configuration 11>
The eleventh configuration of the present invention uses a mask blank with a resist film described in any one of the first to sixth configurations, and a pattern forming step of forming an uneven pattern on at least a thin film of the mask blank;
The manufacturing method of the transfer mask which has these.
According to this configuration, the same effects as described in Configuration 1 can be obtained.

  ADVANTAGE OF THE INVENTION According to this invention, the technique which can form a favorable resist pattern can be provided, neutralizing the charge-up at the time of electron beam irradiation irrespective of an environment.

It is a section schematic diagram of a mask blank with a resist film in this embodiment. It is the cross-sectional schematic of the mask blank with a resist film in a modification. It is a cross-sectional schematic diagram which shows the manufacturing method of the mask blank with a resist film in this embodiment.

Hereinafter, embodiments of the present invention will be described in detail.
In the present embodiment, description will be given in the following order.
1. Mask blank with resist film 1-A) Substrate with thin film 1-B) Resist film 1-C) Water-soluble resin film (organic conductive film)
1-D) Inorganic conductive film Method for Producing Mask Blank with Resist Film 2-A) Preparatory Step for Substrate with Thin Film (Mask Blank) 2-B) Step for Forming Resist Film 2-C) Step for Forming Water-soluble Resin Film (Organic Conductive Film) 2-D) Inorganic Conductive Film Forming Step For configurations not described below, a known configuration (for example, Japanese Patent Application Laid-Open No. 2013-257593 by the present applicant) may be adopted as appropriate. In the present specification, for example, the contents of JP2013-257593A are described with respect to matters not particularly mentioned, such as the configuration of a thin film.

<1. Mask blank with resist film 1>
A mask blank 1 with a resist film in this embodiment will be described with reference to FIG. FIG. 1 is a schematic sectional view of a mask blank 1 with a resist film in the present embodiment. As shown in FIG. 1, in the mask blank 1 with a resist film in the present embodiment, a thin film 11 is formed on the main surface of a substrate 10, and a resist film 12 is formed on the thin film 11. Each configuration will be described below.

1-A) Substrate with thin film (mask blank 5)
As the substrate 10 in the present embodiment, 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 the 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.

  Next, as shown in FIG. 1, a thin film 11 is formed on the main surface of the substrate 10. If the specific structure of the thin film 11 is enumerated, the following (1) to (4) may be mentioned. In the present specification, “to” means a predetermined numerical value and a predetermined numerical value.

(1) Binary mask thin film 11
When producing a binary mask blank, the thin film 11 which has the light shielding film 111 is formed on the board | substrate 10 which has translucency with respect to the light of exposure wavelength.
This light shielding film 111 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, the light shielding film 111 comprised with chromium and the chromium compound which added 1 or more types of elements chosen from elements, such as oxygen, nitrogen, and carbon, to chromium is mentioned. For example, the light shielding film 111 comprised with the tantalum compound which added 1 or more types of elements chosen from elements, such as oxygen, nitrogen, and boron, to tantalum is mentioned.
The thin film 11 has a light shielding film 111 having a two-layer structure of a light shielding layer and a main surface antireflection layer, and a three-layer structure in which a back surface antireflection layer is added between the light shielding layer and the substrate 10. and so on. Further, a composition gradient film in which the composition in the film thickness direction of the light shielding film 111 is different continuously or stepwise may be used.
Alternatively, the thin film 11 having an etching mask film on the light shielding film 111 may be used. This etching mask film has an etching selectivity (etching resistance) with respect to the etching of the light shielding film 111 containing a transition metal silicide, in particular chromium, or a chromium compound in which elements such as oxygen, nitrogen, and carbon are added to chromium. It is preferable to comprise with the material which becomes. At this time, the transfer mask may be manufactured with the etching mask film remaining on the light shielding film 111 by providing the etching mask film with an antireflection function.

(2) Binary mask thin film 11 having another configuration
Another example of the binary mask thin film 11 is a structure having a light shielding film 111 made of a material containing a compound of transition metal and silicon (including transition metal silicide, particularly molybdenum silicide).
The light shielding film 111 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. The light shielding film 111 may be made of 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 111 is formed of a molybdenum silicide compound, a two-layer structure of a light shielding layer (MoSi or the like) and a main surface antireflection layer (MoSiON or the like) or between the light shielding layer and the substrate 10 is used. There is a three-layer structure to which a back surface antireflection layer (MoSiON or the like) is added.
Further, a composition gradient film in which the composition in the film thickness direction of the light shielding film 111 is different continuously or stepwise may be used.

(3) Thin film 11 of halftone phase shift mask
In the case of producing a halftone phase shift mask, a transition metal and a compound of silicon (including transition metal silicide, particularly molybdenum silicide) are included on the substrate 10 that is transparent to the wavelength of exposure light used during transfer. A thin film 11 having a light semi-transmissive film 110 made of a material is formed.
The light semi-transmissive film 110 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 degrees). Note that the halftone phase shift mask has a light semi-transmission portion obtained by patterning the light semi-transmission film 110 and a light transmission that transmits light having an intensity that contributes substantially to exposure without the light semi-transmission film 110 formed. The light semi-transmission part and the light transmission part by causing the phase of the light to be substantially inverted with respect to the phase of the light transmitted through the light transmission part. The light passing through the vicinity of the boundary and entering the other region by the diffraction phenomenon cancels each other, and the light intensity at the boundary is made almost zero to improve the contrast of the boundary, that is, the resolution.
The light semi-transmissive film 110 is made of, for example, a material containing a compound of a transition metal and silicon (including a transition metal silicide), and includes a material having these transition metal and silicon and oxygen and / or nitrogen as main components. It is done. 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 where the light-shielding film 111 is provided on the light-semitransmissive film 110, the material of the light-semitransmissive film 110 includes a transition metal and silicon. In particular, it is preferable to use chromium or a chromium compound in which an element such as oxygen, nitrogen, or carbon is added to chromium.

(4) Reflective mask thin film 11
The thin film 11 of the reflective mask has a structure in which a multilayer reflective film that reflects exposure light is formed on a substrate 10 and an absorber film that absorbs exposure light is formed in a pattern on the multilayer reflective film. 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 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 12
The resist film 12 in the present embodiment may be formed by forming a known composition by a known method. Moreover, a positive resist may be used, a negative resist may be used, or a chemically amplified resist may be used. For example, a photosensitive resin, a photoacid generator (PAG), a basic compound, a surfactant, an organic solvent that is a solvent, or the like may be used as the resist composition.

1-C) Water-soluble resin film 13 (organic conductive film 13)
The water-soluble resin film 13 in the present embodiment is formed on the main surface of the resist film 12. Although the effect brought about by this configuration has been described above, as one of the effects, if the water-soluble resin film 13 is water-soluble, the inorganic conductive film formed on the water-soluble resin film 13 No. 14 can be reliably removed by pre-rinsing with water or an alkaline solution or development.

  Examples of the water-soluble resin film 13 include polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), polyacrylic acid polymer, polyacrylamide (PAM), polyethylene oxide (PEO), and polyaniline which is a conductive polymer. . Although one of the materials listed here is a conductive polymer, the water-soluble resin film 13 is particularly preferably an organic conductive film 13 made of a conductive polymer. The reason for this is as described above. However, since the water-soluble resin film 13 is made of a conductive polymer, the inorganic conductive film 14 described later can be further thinned. Even if the inorganic conductive film 14 is too thin and a portion where the inorganic conductive film 14 is not formed (that is, a film cut) occurs, the organic conductive film 13 is refrained from back-up, thereby preventing charge-up. Static elimination is performed reliably. The conductive polymer may be other than polyaniline, and a known polymer may be used.

However, the water-soluble resin film 13 is not an essential requirement in the present invention. For example, as shown in FIG. 2, even if the inorganic conductive film 14 is formed directly on the main surface of the resist film 12 without providing the water-soluble resin film 13, the effects of the present invention can be fully enjoyed. In that case, since there is no back-filling in conductivity described above, it is necessary to form the inorganic conductive film 14 on the main surface of the resist film 12 without making it extremely thin.
Therefore, the expression “on the resist film” in this specification includes a case where a target film is formed so as to be in contact with the main surface of the resist film 12, and so that it is in contact with the main surface of the resist film 12. This includes the case where a target film is formed on the main surface of another film after another film is formed.

  The organic conductive film 13 is preferably formed so as to cover the main surface of the resist film 12 (more specifically, so as to cover the side surfaces). The same applies to the inorganic conductive film 14 to be described later, and the inorganic conductive film 14 is also formed so as to cover the main surface of the resist film 12 and further the organic conductive film 13 (more specifically, so as to cover the side surfaces). preferable. By forming the organic conductive film 13 and the inorganic conductive film 14 on the organic conductive film 13 as described above, it is possible to perform static elimination by making contact with the ground at a portion other than the main surface, thereby improving workability.

1-D) Inorganic conductive film 14
The inorganic conductive film 14 in this embodiment is formed on the main surface of the organic conductive film 13. The inorganic conductive film 14 includes at least one of Mo and W. Therefore, an inorganic conductive film 14 containing Mo and W may be provided. The inorganic conductive film 14 may be composed of a plurality of layers. For example, a Mo layer may be formed on the Mo oxide layer, or a similar structure may be provided with W. Further, the vertical relationship between the Mo oxide layer and the Mo layer may be interchanged, the Mo oxide layer and the W oxide layer may be provided, or the Mo layer and the W layer may be provided. Each layer can be configured by interweaving Mo and W as appropriate.

When the inorganic conductive film 14 contains Mo as a main component, as described above, the following advantages are obtained.
The metal Mo forms MoO ₃ on the outermost surface by natural oxidation, but since the bulk can maintain the metal state, the conductivity can be maintained at a high level. Even if the surface of the metal molybdenum is formed by oxide by natural oxidation, it can be easily removed by pre-rinsing with an alkaline solution before development or a developer.

  Here, the oxygen used for “oxidation” may be oxygen bonded to Mo or W by natural oxidation, or oxygen bonded by oxidation formed by annealing, and of course, the inorganic conductive film 14. A case where an oxide target is used to form a sputtering film in advance at the time of formation or a structure in which an oxide is formed by reactive sputtering using a metal target is also included.

As a matter of course, a metal Mo alone may be used as the inorganic conductive film 14, and a Mo-based compound may be used. As the Mo-based compound, any type can be used as long as it can be neutralized against charge-up, but molybdenum oxide is preferable according to the inventors' investigation.
Metal Mo alone is soluble in an alkaline solution and has excellent conductivity. Among molybdenum oxides, MoO ₂ (IV), Mo ₂ O ₅ (V), and MoO ₃ (VI) are suitable in terms of conductivity. MoO ₃ (VI) is soluble in an alkaline solution. Other molybdenum oxides (for example, Mo _n O _3n-1, which is an intermediate composition between MoO ₂ (IV) and MoO ₃ (VI)) are also known, and can be applied to the present invention as necessary.

On the other hand, when the inorganic conductive film 14 is mainly composed of an oxide of W (particularly an oxide mainly composed of a WO ₂ structure), as described above, WO ₂ is a good conductor and is alkali-soluble. Therefore, no residue remains on the surface.

Of course, a metal W alone may be used as the inorganic conductive film 14, and a W-based compound may be used. The W-based compound is not particularly limited as long as it can be neutralized against charge-up, but tungsten oxide is preferred according to the inventors' investigation.
Metal W alone is soluble in an alkaline solution and has excellent conductivity. Among tungsten oxides, W ₂ O ₃ (III), WO ₂ (IV), and WO ₃ (VI) are suitable in terms of conductivity. These are soluble in alkaline solutions.

  In addition, the “main component” in the present specification indicates that it is the largest number of compounds constituting the inorganic conductive film 14. For example, when most of the inorganic conductive film 14 is occupied by Mo and a Mo-based compound (for example, an oxide), it can be said that Mo is the main component in the inorganic conductive film 14.

Moreover, the film thickness of the inorganic conductive film 14 is preferably 1 nm to 10 nm, more preferably 2 nm to 5 nm. As described above, as described above, the formation state of the inorganic conductive film 14 can be kept good, and the charge can be sufficiently removed. In addition, it is possible to suppress the risk that the residue when the inorganic conductive film 14 is removed becomes a foreign substance because the labor for producing the inorganic conductive film 14 is not so much required. Further, the electron beam irradiation can be favorably performed on the resist film 12 through the inorganic conductive film.
Note that the film thickness may be adjusted as appropriate in accordance with the conductivity of the material of the inorganic conductive film. For example, in the case of a film of an oxide of Mo or W, the specific resistance of a substance is higher than that of a metal film, so that the film is preferably formed in the range of 3 nm to 10 nm. In the case of a Mo or W metal film (including a surface-oxidized state), the specific resistance of the substance is relatively low, so that the film is preferably formed to a thickness of 1 nm to 5 nm.

The sheet resistance of the conductive inorganic film 14 is ^{10Ω / □ ~1.0 × 10 6 Ω} / □ is preferably in the range ^{of, 100Ω / □ ~1.0 × 10 6} Ω / □ range is more preferred. As described above, as described above, it is possible to suppress the possibility that electrons flowing through the inorganic conductive film 14 affect the resist film and lower the sensitivity. In addition, it is possible to provide sufficient charge removal capability, and for example, it is possible to surely form a pattern with a pitch of 70 nm.

  The above is the main configuration of the mask blank 1 with a resist film in the present embodiment. In addition, as long as it has said structure, you may provide another well-known layer (film | membrane) in the mask blank 5. FIG.

<2. Manufacturing method of mask blank 1 with resist film>
Next, the manufacturing method of the mask blank 1 with a resist film in this embodiment is demonstrated using FIG. FIG. 3 is a schematic cross-sectional view showing a method for manufacturing the mask blank 1 with a resist film in the present embodiment. The contents of the following steps are <1. There is also an overlap with the contents described in the mask blank with resist film 1>. Therefore, for contents not described below, <1. As described in the mask blank with resist film 1>.

  In this embodiment, an example in which the substrate 10 is prepared and the thin film 11 is formed on the substrate 10 in the following 2-A) substrate preparation 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 the resist film 12 is formed thereon is also included in the form of the present invention.

2-A) Substrate with Thin Film (Mask Blank) Preparation Step First, the substrate 10 is prepared. Next, the thin film 11 is formed on the main surface of the substrate 10. As a specific configuration and preparation method, a known method may be used. In the present embodiment, a case where a substrate 10 made of quartz glass provided with a light semi-transmissive film 110 and a light shielding film 111 is used as the mask blank 5 will be described.

2-B) Resist Film Formation Step In this step, the resist film 12 is formed on the main surface of the thin film 11 with a positive resist solution. As a specific method, a known method may be used. As an example, after the HMDS process is performed on the main surface of the thin film 11, a resist solution is applied to the main surface of the thin film 11 by spin coating, and a baking process is performed. Thus, the resist film 12 is formed so as to cover the thin film 11.

2-C) Water-soluble resin film (organic conductive film) forming step In this step, the organic conductive film 13 is formed on the main surface of the resist film 12 with an organic conductive polymer. As a specific method, a known method may be used. As an example, a raw material liquid of an organic conductive polymer is applied to the main surface of the resist film 12 by spin coating, and rough drying is performed. Thus, the organic conductive film 13 is formed so as to cover the resist film 12. Note that this step is not essential in the present invention, as described in the section 1-C) Water-soluble resin film 13 (organic conductive film 13).

2-D) Inorganic conductive film forming step In this step, the inorganic conductive film 14 is formed on the main surface of the organic conductive film 13. As a specific method, a known method may be used, the film may be formed by sputtering film formation, or film formation by vacuum deposition may be used. However, as described above, sputtering film formation is preferable. By using a target of molybdenum oxide or tungsten oxide having a desired oxygen content in advance, the inorganic conductive film 14 having a desired degree of oxidation can be formed.

As described above, the mask blank 1 with a resist film in the present embodiment is manufactured. Of course, a cleaning / drying step and the like necessary for the production of the mask blank 1 with a resist film may be appropriately performed.
A transfer mask may be produced from the mask blank 1 with a resist film. After performing exposure (drawing) by electron beam irradiation corresponding to a predetermined pattern to the mask blank 1 with a resist film, a pattern forming process is performed in which a resist pattern is formed by development. In addition to the above-described method, a known method may be used as a specific method for static elimination. Finally, the thin film 11 having a predetermined uneven pattern is produced. Note that the pattern forming step referred to here may refer to forming a resist pattern, or may further proceed from there to indicate forming an uneven pattern on the thin film 11 and the substrate 10 itself. . Also in this case, a cleaning / drying step and the like necessary for producing the transfer mask may be appropriately performed.

Next, an Example is shown and this invention is demonstrated concretely. Of course, the present invention is not limited to the following examples. In addition, the content as described in Unexamined-Japanese-Patent No. 2013-257593 is employ | adopted for the matter which has no special mention.
In Example 1, the inorganic conductive film 14 mainly composed of Mo was directly formed on the main surface of the resist film 12.
In Example 2, as in the present embodiment, the organic conductive film 13 is formed on the main surface of the resist film 12, and the inorganic conductive material mainly composed of Mo is formed on the main surface of the organic conductive film 13. A film 14 was formed.
In Example 3, the inorganic conductive film 14 mainly composed of Mo has a two-layer structure. Specifically, a Mo oxide layer was formed on the main surface of the resist film 12, and a Mo layer was formed on the main surface of the Mo oxide layer.
In Example 4, an inorganic conductive film 14 containing W as a main component was formed unlike Example 2 while following Example 2.
Comparative Example 1 shows an example in which the inorganic conductive film 14 is not provided in Example 2.

<Example 1>
(Sample preparation)
2-A) Substrate with Thin Film (Mask Blank) Preparation Step Translucent substrate 10 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 (hereinafter referred to as translucent light) Also referred to as a conductive substrate 10).

First, a light semi-transmissive film 110 was formed on the light transmissive substrate 10.
On a substrate 10 made of synthetic quartz glass, using a single wafer sputtering apparatus, a mixed target of molybdenum (Mo) and silicon (Si) (molar ratio Mo: Si = 10: 90) is used as a sputtering target, Reactive sputtering (DC sputtering) using a mixed gas of argon (Ar), nitrogen (N ₂ ), and helium (He) (flow ratio Ar: N ₂ : He = 5: 49: 46, pressure = 0.3 Pa) as a sputtering gas. : DC power 3.0 kW), a MoSiN film (lower layer) was formed with a film thickness of 69 nm.
Next, the substrate 10 on which the MoSiN film was formed was subjected to heat treatment using a heating furnace in the atmosphere at a heating temperature of 450 ° C. and a heating time of 1 hour. This MoSiN film had an transmittance of 6.16% and a phase difference of 184.4 degrees in an ArF excimer laser.

Next, a light shielding film 111 having a three-layer structure was formed on the light semitransmissive film 110.
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 = 20: 35: 10: 30, pressure = 0.2 Pa) was used as a sputtering gas to form a CrOCN film with a film thickness of 30 nm by reactive sputtering (DC sputtering: DC power 1.7 kW) (first Light shielding film 111a).
Further, using the same chromium (Cr) target, a mixed gas of argon (Ar) and nitrogen (N ₂ ) (flow rate ratio Ar: N ₂ = 25: 75, pressure = 0.1 Pa) is used as a sputtering gas, and the reaction is performed. A CrN film having a thickness of 4 nm was formed by reactive sputtering (DC sputtering: DC power 1.7 kW) (second light shielding film 111b).
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 = 20: 35: 5: 30, pressure = 0.2 Pa) was used as a sputtering gas to form a chromium-rich CrOCN film with a film thickness of 14 nm (DC sputtering: DC power 1.7 kW). Three light shielding films 111c).
By the above procedure, a light-shielding film 111 made of a chromium-based material having a three-layer structure including a lowermost layer made of CrOCN, a lower layer made of CrN, and an upper layer made of CrOCN was formed with a total film thickness of 48 nm from the phase shift film side.
The substrate with a thin film was obtained by the above procedure. The optical density when the light semi-transmissive film 110 and the light shielding film 111 were combined was set to 3.0 (λ = 193 nm). Further, the surface reflectance of the light shielding film 111 with respect to the wavelength of exposure light (λ = 193 nm) was 20%.

2-B) Resist Film Formation Step A chemical amplification type positive resist (PRL009S manufactured by Fuji Film Electromaterial Co., Ltd.) is applied to the surface of the thin film 11 by a spin coating method, followed by baking at 190 ° C. for 60 seconds, A resist film 12 was formed.

2-D) Inorganic conductive film forming step On top of that, a MoO _X film having a thickness of 5 nm was formed as the inorganic conductive film 14. Specifically, using a molybdenum molybdenum (Mo) target, a mixed gas of argon (Ar) and oxygen (O ₂ ) (flow rate ratio: Ar: O ₂ = 90: 10, pressure = 0.1 Pa) is used as a sputtering gas, and the reaction Film formation was performed by reactive sputtering (DC sputtering: DC power 1.5 kW).

<Example 2>
In this example, as in the present embodiment, the organic conductive film 13 is formed on the main surface of the resist film 12, and the inorganic conductive material mainly composed of Mo is formed on the main surface of the organic conductive film 13. A film 14 was formed. In addition, since it was the same as that of Example 1 except it, only the preparation methods of the organic electroconductive film | membrane 13 are described.

2-C) Water-soluble resin film (organic conductive film) formation step A polyaniline-based organic conductive resin film (AQUA SAVE manufactured by Mitsubishi Rayon Co., Ltd.) is applied to the main surface of the resist film 12 by spin coating, and then 120 Rough drying was performed at 0 ° C. to form an organic conductive film 13 having a thickness of 10 nm.

2-D) Inorganic conductive film forming step On top of that, a MoO _X film having a thickness of 3 nm was formed as the inorganic conductive film 14. More specifically, a molybdenum (Mo) target was used, and argon (Ar) (pressure = 0.1 Pa) was used as a sputtering gas (DC sputtering: DC power 1.5 kW) to form a film.
Using the above method, a mask blank 1 with a resist film in this example was produced.
In addition, it was set as the same as Example 1 except the above-mentioned content.

<Example 3>
In this embodiment, the inorganic conductive film 14 mainly composed of Mo has a two-layer structure. Specifically, a Mo oxide layer was formed on the main surface of the resist film 12, and a Mo layer was formed on the main surface of the Mo oxide layer. The rest was the same as in Example 1.

2-D) Inorganic conductive film forming step A Mo film was formed thereon with a thickness of 3 nm. More specifically, a molybdenum (Mo) target was used, and argon (Ar) (pressure = 0.1 Pa) was used as a sputtering gas (DC sputtering: DC power 1.5 kW) to form a film.
A MoO _X film was formed thereon with a thickness of 3 nm. More specifically, a molybdenum (Mo) target is used, a mixed gas of argon (Ar) and oxygen (O ₂ ) (flow rate ratio: Ar: O ₂ = 90: 10, pressure = 0.1 Pa) is used as a sputtering gas, and the reactivity is increased. Film formation was performed by sputtering (DC sputtering: DC power 1.5 kW).
Using the above method, a mask blank 1 with a resist film in this example was produced.

<Example 4>
In this example, the inorganic conductive film 14 containing W as a main component was formed unlike the example 2 while following the example 2. An alkaline solution was used for pre-rinsing for removing the inorganic conductive film 14. In addition, since it was the same as that of Example 1 except it, only the preparation methods of the inorganic electroconductive film | membrane 14 are described.

2-D) Inorganic conductive film forming step On the organic conductive film 13, a WO _X film was formed to a thickness of 5 nm. More specifically, a tungsten (W) target is used, and a mixed gas of argon (Ar) and oxygen (O ₂ ) (flow rate ratio: Ar: O ₂ = 90: 10, pressure = 0.1 Pa) is used as a sputtering gas. Film formation was performed by reactive sputtering (DC sputtering: DC power 1.5 kW).
Using the above method, a mask blank 1 with a resist film in this example was produced.

<Comparative Example 1>
In this comparative example, a sample was prepared in the same manner as in Example 2 except that the inorganic conductive film 14 (Mo film) was not formed in Example 2.

<Evaluation>
A pattern was drawn on the resist film 12 of the mask blank 5 of Examples 1 to 4 and Comparative Example 1 using an electron beam drawing apparatus manufactured by Elionix. The pattern was exposed so that the width (half pitch) of the convex portions (lines) of the resist pattern was 30 nm to 90 nm, and the ratio of lines to spaces was 1: 1. After drawing, the film was heated at 130 ° C. for 600 seconds.
Thereafter, pre-rinsing was performed on Examples 1 to 4, and the inorganic conductive film 14 was removed with pure water (ion exchange water) or an alkaline solution. Subsequent development was performed. Development was performed by supplying a developing solution (THAM: tetramethylammonium hydroxide) to the substrate 10 at 5 mL / second.
Then, drying rotation for 60 seconds was performed at high speed rotation, and it was made to dry naturally. In addition, the process after the removal of a resist pattern was not performed.
When the resist pattern was observed with the electron microscope with respect to the sample obtained in this way, in Examples 1-4, the pattern was able to be satisfactorily formed in the predetermined position in the half pitch of size. From this, it was found that in Examples 1 to 4, charging during the formation of the resist pattern was quickly eliminated.
On the other hand, in Comparative Example 1, there was a phenomenon in which the position of the pattern actually formed deviated from the predetermined position to be drawn when the half pitch was smaller than 70 nm. From this, it was found that even when the organic conductive film 13 was formed, the charging at the time of electron beam drawing could not be eliminated if the pattern dimension was narrow.

DESCRIPTION OF SYMBOLS 1 ......... Mask blank 5 with a resist film ......... Mask blank 10 ... Substrate 11 ... Thin film 110 ... Light semi-transmissive film 111 ... Light shielding film 111a ... First light shielding film 111b ... Second light shielding film 111c ... Third light shielding Film 12... Resist film 13... Water-soluble resin film (organic conductive film)
14 …… Inorganic conductive film

Claims (12)

A mask blank with a resist film comprising a substrate having a thin film and a resist film formed on the surface of the thin film,
An inorganic conductive film is formed on the resist film,
The inorganic conductive film includes at least one of molybdenum and tungsten,
A mask blank with a resist film, wherein a water-soluble resin film is formed between the resist film and the inorganic conductive film.   2. The mask blank with a resist film according to claim 1, wherein the water-soluble resin film is an organic conductive film made of a conductive polymer.   The mask blank with a resist film according to claim 1 or 2, wherein the inorganic conductive film has a thickness of 1 nm to 10 nm.   4. The mask blank with a resist film according to claim 1, wherein the inorganic conductive film as a whole contains at least one of molybdenum oxide and tungsten oxide. The inorganic conductive film includes at least one of MoO ₃ , Mo ₂ O ₅ , MoO ₃ , W ₂ O ₃ , WO ₂ , and WO _3. Mask blank with resist film. A method of manufacturing a mask blank with a resist film,
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;
A water-soluble resin film forming step of forming a water-soluble resin film on the resist film;
An inorganic conductive film forming step of forming an inorganic conductive film containing at least one of molybdenum and tungsten on the water-soluble resin film;
A method for producing a mask blank with a resist film, comprising:   The method for producing a mask blank with a resist film according to claim 6, wherein the water-soluble resin film is an organic conductive film composed of a conductive polymer.   The method of manufacturing a mask blank with a resist film according to claim 6 or 7, wherein the water-soluble resin film has a thickness of 1 nm to 10 nm.   9. The method of manufacturing a mask blank with a resist film according to claim 6, wherein the inorganic conductive film includes at least one of molybdenum oxide and tungsten oxide as a whole. The inorganic conductive film includes at least one of MoO ₃ , Mo ₂ O ₅ , MoO ₃ , W ₂ O ₃ , WO ₂ , and WO _3. Of manufacturing mask blank with resist film.   The method for manufacturing a mask blank with a resist film according to claim 6, wherein the inorganic conductive film forming step is performed by sputtering film formation. 6. A method for producing a transfer mask, comprising: a step of forming a concavo-convex pattern on at least the thin film of the mask blank using the mask blank with a resist film according to claim 1.

Images