JP2019082714A - Mask blank having resist film, manufacturing method thereof and manufacturing method of mask for transfer - Google Patents

Abstract

To provide a technique capable of forming an excellent resist pattern while discharging without depending on an environment with regard to charging-up at electron beam irradiation.SOLUTION: A mask blank 1 having a resist film includes: a substrate 10 having a thin film 11; and a resist film 12 formed on a surface of the thin film 11. The mask blank 1 having a resist film further includes, on the resist film 12, an inorganic electroconductive film 14 containing at least one of Mo and W.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a mask blank with a resist film, a method of manufacturing the same, and a method of manufacturing 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, electron beam irradiation is performed to form a resist pattern, and a resist pattern is further formed. Is transferred to the light shielding film or the phase shift film by etching.

  Although the resist pattern formation by electron beam irradiation performed in this processing step has to be performed at a very accurate position, since a commonly used resist film is an insulator, charge accumulation (charge up) in the resist film Can happen. Then, due to the influence of the 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 precision of the resist pattern is lowered.

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

  Although there also existed a method of using surfactant instead of said method, environment dependency that conductivity changed with environment was large. In addition, it has also been required to use materials from organic solvents to water.

  As a result, the use of water-soluble conductive polymers for the suppression of charge-up has become mainstream at present. An example of the technology is the technology 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, when forming a pattern having a pitch of, for example, 50 nm or less, higher accuracy is required with respect to the position of the resist pattern. There is a current situation that is becoming scarce. Also, as described above, regardless of how water-soluble polymer is used, since it is an organic compound, its conductivity becomes environmentally dependent.

  An object of the present invention is to provide a technology capable of forming a good resist pattern while performing charge removal independently of environment with respect to charge-up during electron beam irradiation.

The present inventors diligently studied to solve the above problems. As a result, the inventor of the present invention does not focus on the water-soluble conductive polymer (more specifically, organic conductive film) currently in the mainstream, but forms a conductive film on the resist film using an inorganic material. I thought of the method. This is different from a long time ago technology that used a resin component in which a conductive filler was dispersed for suppression of charge up, and an inorganic conductive film itself is provided on a resist film. It is a technique conceived with a completely new idea.
The configuration of the present invention made based on this finding is as follows.

<Configuration 1>
The first configuration of the present invention is a mask blank with a resist film.
The present 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 provided on the resist film is an inorganic conductive film containing at least one of Mo and W, the conductivity is dramatically improved compared to the case of the organic conductive film. Improve. By way of example, the oxides of Mo (for example III, IV) or W (IV) have good conductivity. Moreover, since conductivity is ensured even with an inorganic conductive film of 5 nm or less, it becomes possible to effectively remove the charge of the resist film generated at the time of electron beam irradiation, and thus a resist pattern of 50 nm or less in size is formed. It is possible to This means that it becomes possible to make the film for suppressing charge-up thinner than the organic conductive film of Patent Document 1 or 2. As a result, it becomes possible to satisfactorily apply a fine pattern to the mask blank. Furthermore, 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 stability of physical properties such as conductivity.
In addition, since the film containing at least one of Mo and W is used, it is relatively easily soluble in water or an aqueous alkaline solution, and the workability is remarkably improved.
Furthermore, at the stage where the inorganic conductive film is provided, so to speak, packing with a metal film is performed on the resist film, so that the resist film becomes airtight, and at the stage where the inorganic conductive film is provided, for example, storage of the resist film It is in a situation where no deterioration of the resist film due to oxygen or the like present in the medium atmosphere, or deterioration due to outgassing of the plastic case used for transportation occurs. That is, the above-mentioned inorganic conductive film also plays a role as a protective film of a resist film.
As described above, according to the present configuration, it is possible not only to carry out the charge removal more efficiently than in the case of the organic conductive film, but also to remarkably suppress the change with time of the quality of the resist film. As a result, it is possible to form a good resist pattern while performing charge removal independently of environment with respect to charge-up at the time of electron beam irradiation.

<Configuration 2>
According to a second structure of the present invention, in the structure described in the first aspect, 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 drawing is performed to form a predetermined pattern, since the inorganic conductive film has a low resistance, the electron beam has an electric energy of Attenuation is reduced. On the other hand, because of the extremely low resistance of the inorganic conductive film, there is also a possibility that the exposure may affect the area wider 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 forming the relatively high-resistance resin film in this way, it is possible to effectively suppress the sensitivity fluctuation of the resist surface. Moreover, if the resin film is water-soluble, the inorganic conductive film formed on the resin film is reliably removed by pre-rinsing with water, an alkaline solution or the like, or development.

<Configuration 3>
According to a third structure of the present invention, in the structure described in the second aspect, the water-soluble resin film is an organic conductive film formed of a conductive polymer.
The inorganic conductive film can be further thinned by forming the above water-soluble resin film with a conductive polymer. Even if the inorganic conductive film is too thin and the film is cut off, the charge removal due to charge-up can be reliably performed because the organic conductive film is reserved as backfill. In addition, since the organic conductive film made of the conductive polymer has higher resistance than the inorganic conductive film, it has the same electron conductivity, so the electron is propagated to the resist film due to charge up. It is possible to suppress the extinction of the beam. As a result, the sensitivity of the resist film can be maintained at a particularly high level, and a fine pattern can be formed.

<Configuration 4>
A fourth configuration of the present invention is the configuration according to any one of the first to third aspects, wherein the film thickness of the inorganic conductive film is 1 nm to 10 nm, preferably 2 nm to 5 nm.
When the film thickness of the inorganic conductive film is 1 nm or more, it is possible to maintain the formation state of the inorganic conductive film in a good condition, and it becomes possible to perform sufficient charge removal. If the thickness is 10 nm or less, it is also possible to save time and effort for producing the inorganic conductive film, and to suppress the risk that foreign matter will be left after removing the inorganic conductive film. In addition, electron beam irradiation can be favorably performed on the resist film through the inorganic conductive film. The effect is more pronounced at 2 nm to 5 nm.

<Configuration 5>
A fifth structure of the present invention is the structure according to any one of the first to fourth aspects, wherein the inorganic conductive film contains Mo as a main component. In particular, the inorganic conductive film preferably contains Mo oxide.
When metal Mo is formed into a film by sputtering, Mo oxide is formed by natural oxidation. Mo oxide has conductivity, and since the bulk can maintain the metal state, conductivity sufficient for static elimination can be maintained even with a film thickness of 5 nm or less. In the case where the surface of metal Mo is formed as an oxide by natural oxidation, it can be easily removed by pure water (ion-exchanged water) before development or by a pre-rinse with an alkaline solution or a developer.

<Configuration 6>
A sixth structure of the present invention is the structure according to any one of the first to fourth aspects, wherein 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 alkali-soluble, it can be easily removed by pure water (ion-exchanged water) before development or by pre-rinsing with an alkaline solution or an alkaline developer. Therefore, the residue derived from the inorganic conductive film does not remain on the surface.

<Configuration 7>
The 7th composition of the present invention is a manufacturing method of a mask blank with a resist film.
The manufacturing method comprises: 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 a resist film;
It is included.
According to this configuration, the same effect as described in Configuration 1 is obtained.

<Configuration 8>
The eighth configuration of the present invention is the configuration according to the seventh, which is between the resist film forming step and the inorganic conductive film forming step.
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 configuration of the present invention is the configuration described in the eighth, wherein the water-soluble resin film is an organic conductive film composed of a conductive polymer.
According to this configuration, the same effect as described in Configuration 3 can be obtained.

<Configuration 10>
A tenth structure of the present invention is the structure according to any one of the seventh to ninth aspects, wherein the inorganic conductive film forming step is performed using sputtering film formation.
An inorganic conductive film having a desired degree of oxidation can be formed by using a target of molybdenum oxide or tungsten oxide having a desired oxygen content in advance.

<Structure 11>
According to an eleventh configuration of the present invention, there is provided a pattern forming step of forming a concavo-convex pattern on at least a thin film of the mask blank using the mask blank with a resist film described in any one of the first to sixth configurations.
A method of manufacturing a transfer mask.
According to this configuration, the same effect as described in Configuration 1 is obtained.

  According to the present invention, it is possible to provide a technology capable of forming a good resist pattern while performing charge removal independently of environment with respect to charge-up during electron beam irradiation.

It is the cross-sectional schematic of the 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 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.
The present embodiment will be described in the following order.
1. Resist film coated mask blank 1-A) Thin film coated substrate 1-B) Resist film 1-C) Water soluble resin film (organic conductive film)
1-D) Inorganic conductive film Manufacturing method of mask blank with resist film 2-A) Substrate with thin film (mask blank) preparation process 2-B) Resist film formation process 2-C) Water-soluble resin film (organic conductive film) formation process 2-D) Inorganic Step of Forming Conductive Film In addition, as for the configuration not described below, a known configuration (for example, JP 2013-257593A by the present applicant) may be adopted as appropriate. In the present specification, the content of Japanese Patent Application Laid-Open No. 2013-257593 is described with respect to matters without particular mention such as the configuration of a thin film, for example.

<1. Resist film mask blank 1>
The mask blank 1 with a resist film in this embodiment is demonstrated using FIG. FIG. 1 is a schematic cross-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 component will be described below.

1-A) Substrate with thin film (mask blank 5)
A glass substrate can be used as the substrate 10 in the present embodiment. In the case of a transmissive mask, the substrate 10 is selected to be a glass material having high transmittance to exposure light when forming a pattern on a wafer. In the case of a reflective mask, a low thermal expansion glass is selected that can minimize the thermal expansion of the substrate 10 with the energy of the exposure light.
Specifically, in the case of a transmission mask (for example, binary mask, phase shift mask and gray tone mask), the material of the substrate 10 is synthetic quartz glass, soda lime glass, aluminosilicate glass, borosilicate glass, alkali-free Glass etc. are mentioned. As a detailed example, for the substrate 10 of a transfer type mask using an ArF excimer laser with a wavelength of 193 nm or a KrF excimer laser with a wavelength of 254 nm as the exposure light, synthetic quartz glass having high transmittance to light with a wavelength of 300 nm or less is preferably used. be able to.
In the case of an EUV mask which is a reflective mask, the substrate 10 is more preferably in the range of about 0 ± 1.0 × 10 ⁻⁷ / ° C. to suppress distortion of the transferred pattern due to heat during exposure. Is preferably a glass material having a low thermal expansion coefficient within the range of about 0 ± 0.3 × 10 ⁻⁷ / ° C., and SiO ₂ —TiO ₂ -based glass can be preferably used.

  Next, as shown in FIG. 1, a thin film 11 is formed on the main surface of the substrate 10. If the specific composition of the thin film 11 is listed, the following (1)-(4) will be mentioned. In the present specification, "-" means a predetermined value or more and a predetermined value or less.

(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.
The light shielding film 111 is made of a material containing transition metals such as chromium, tantalum, ruthenium, tungsten, titanium, hafnium, molybdenum, nickel, vanadium, zirconium, niobium, palladium, rhodium or the like, or a compound thereof. For example, the light shielding film 111 may be made of chromium or a chromium compound obtained by adding one or more elements selected from the elements such as oxygen, nitrogen, and carbon to chromium. For example, the light shielding film 111 which 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.
In the thin film 11, the light shielding film 111 has 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 further added between the light shielding layer and the substrate 10. and so on. Also, the composition gradient film may be configured such that the composition in the film thickness direction of the light shielding film 111 varies continuously or stepwise.
In addition, the thin film 11 may have an etching mask film on the light shielding film 111. This etching mask film has an etching selectivity to the etching of the light shielding film 111 containing transition metal silicide (etching resistance), in particular, chromium, or a chromium compound obtained by adding an element such as oxygen, nitrogen, or carbon to chromium. It is preferable to comprise with the following materials. At this time, the transfer mask may be manufactured in a state in which the etching mask film is left on the light shielding film 111 by providing the etching mask film with a reflection preventing function.

(2) Binary mask thin film 11 having another configuration
In addition, as another example of the thin film 11 of the binary mask, a configuration having a light shielding film 111 made of a material containing a compound of a transition metal and silicon (including transition metal silicide, particularly molybdenum silicide) can also be mentioned.
The light shielding film 111 is made of a material containing a compound of a transition metal and silicon, and a material containing these transition metal and silicon and oxygen and / or nitrogen as main components can be mentioned. In addition, the light shielding film 111 may be a material mainly composed of a transition metal, oxygen, nitrogen and / or boron. As a transition metal, molybdenum, tantalum, tungsten, titanium, hafnium, nickel, vanadium, zirconium, niobium, palladium, ruthenium, rhodium, chromium and the like can be applied.
In particular, when the light shielding film 111 is formed of a compound of molybdenum silicide, it has a two-layer structure of a light shielding layer (such as MoSi) and a main surface antireflective layer (such as MoSiON), and further between the light shielding layer and the substrate 10 There is a three-layer structure in which a back surface reflection preventing layer (MoSiON or the like) is added.
Also, the composition gradient film may be configured such that the composition in the film thickness direction of the light shielding film 111 varies continuously or stepwise.

(3) Thin film 11 of halftone phase shift mask
When producing a halftone phase shift mask, a compound of transition metal and silicon (including transition metal silicide, particularly molybdenum silicide) is included on the substrate 10 having transparency to the wavelength of exposure light used during transfer. A thin film 11 having a light transflective film 110 made of a material is formed.
The light transflective film 110 included in the thin film 11 transmits light of an intensity (for example, 1% to 30% with respect to the exposure wavelength) which does not substantially contribute to the exposure, and has a predetermined retardation (for example, 180 degrees). Note that the halftone phase shift mask transmits light that transmits light of an intensity that contributes to exposure, in which the light-semitransparent film 110 is patterned and the light-semitransparent film 110 is not formed. And the light transmitting portion and the light transmitting portion by making the phase of the light transmitted through the light transmitting portion substantially inverted with respect to the phase of the light transmitted through the light transmitting portion. The lights passing through the vicinity of the boundary between the light and the light and coming into each other's region due to diffraction phenomenon mutually cancel each other, and the light intensity at the boundary is made substantially zero to improve the contrast of the boundary, that is, the resolution.
The light transflective film 110 is made of, for example, a material containing a compound of a transition metal and silicon (including a transition metal silicide), and a material containing these transition metal and silicon and oxygen and / or nitrogen as main components is cited. Be As a transition metal, molybdenum, tantalum, tungsten, titanium, hafnium, nickel, vanadium, zirconium, niobium, palladium, ruthenium, rhodium, chromium and the like can be applied.
Further, in the case where the light shielding film 111 is provided on the light semitransmitting film 110, the material of the light semitransmitting film 110 contains a transition metal and silicon. In particular, it is preferable to use a chromium compound having etching selectivity (having etching resistance), or a chromium compound obtained by adding an element such as oxygen, nitrogen or carbon 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. The light (EUV light) incident on the reflective mask mounted on the exposure machine (pattern transfer device) is absorbed by the portion with the absorber film, and the light image reflected by the multilayer reflection film in the portion without the absorber film Is transferred onto the semiconductor substrate through the reflective optical system.
The multilayer reflective film is formed by alternately laminating a high refractive index layer and a low refractive index layer. As an example of the multilayer reflective film, a Mo / Si periodic laminated film in which Mo film and Si film are alternately laminated for about 40 cycles, Ru / Si periodic multilayer film, Mo / Be periodic multilayer film, Mo compound / Si compound periodic multilayer film 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.
Further, the absorber film has a function of absorbing, for example, EUV light which is exposure light, and for example, tantalum (Ta) alone or a material containing Ta as a main component can be preferably used. The crystalline state of such an absorber film preferably has an amorphous or microcrystalline structure from the viewpoint of smoothness and flatness.

1-B) Resist film 12
The resist film 12 in the present embodiment may be formed of a known composition by a known method. Further, a positive resist may be used, a negative resist may be used, or a chemically amplified resist may be used. For example, as the resist composition, a photosensitive resin, a photoacid generator (PAG), a basic compound, a surfactant, an organic solvent which is a solvent, or the like may be used.

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 is described above, as one of the effects, if the water-soluble resin film 13 is water-soluble, an inorganic conductive film formed on the water-soluble resin film 13 No. 14 can be reliably removed by pre-rinsing with water, an alkaline solution or the like or development.

  Examples of the water-soluble resin film 13 include polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), polyacrylic acid-based polymer, polyacrylamide (PAM), polyethylene oxide (PEO), and polyaniline which is a conductive polymer. . Although one of those listed here is a conductive polymer, it is particularly preferable that the water-soluble resin film 13 be an organic conductive film 13 composed of a conductive polymer. The reason is as described above. However, when 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 there is a portion where the inorganic conductive film 14 is not formed (that is, film separation), the organic conductive film 13 is reserved as a backfill, thereby preventing charge up. The static elimination is performed reliably. In addition, as a conductive polymer, it may be except polyaniline, and you may use a well-known thing.

However, the above 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 sufficiently obtained. In that case, since there is no backfilling in the conductivity described above, it is necessary to form the inorganic conductive film 14 on the main surface of the resist film 12 without extremely thinning.
Therefore, the expression “on the resist film” in this specification naturally includes the case where the target film is formed to be in contact with the main surface of resist film 12 and to be in contact with the main surface of resist film 12. This also includes the case where the target film is formed on the main surface of the other film after the other film is formed.

  The organic conductive film 13 is preferably formed to cover the main surface of the resist film 12 (more specifically, to cover the side surfaces). The same applies to the inorganic conductive film 14 described later, and the inorganic conductive film 14 is also formed so as to cover the main surface of the resist film 12 and the organic conductive film 13 (more specifically, to cover the side surfaces). preferable. By forming the organic conductive film 13 and the inorganic conductive film 14 thereon as described above, it becomes possible to make contact with the ground in portions other than the main surface to perform charge removal, and the workability is improved.

1-D) inorganic conductive film 14
The inorganic conductive film 14 in the present embodiment is formed on the main surface of the organic conductive film 13. The inorganic conductive film 14 contains at least one of Mo and W. Therefore, the inorganic conductive film 14 containing Mo and W may be provided. In addition, 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 of W may be provided. 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. Mo and W can be appropriately interwoven in each layer.

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

  Here, the oxygen to be subjected to “oxidation” may be oxygen bonded to Mo or W by natural oxidation, or oxygen formed by oxidation formed by annealing, and, of course, the inorganic conductive film 14 In the case of sputtering deposition using an oxide target at the time of formation, or a configuration in which an oxide is formed by reactive sputtering using a metal target is also included.

Mo-based compounds may be used as well as metal Mo alone may be used as the inorganic conductive film 14. As the Mo-based compound, any type can be used as long as it can be used for charge-up, but molybdenum oxide is preferable in the investigation of the inventor.
The metal Mo alone is soluble in an alkaline solution and is excellent in 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 alkaline solutions. Molybdenum oxides other than this (for example, Mo _n O _{3 n-1} which is an intermediate composition of MoO ₂ (IV) and MoO ₃ (VI)) are also known, and can be applied to the present invention as needed.

On the other hand, when the inorganic conductive film 14 contains an oxide of W (in particular, an oxide mainly having a WO ₂ structure) as a main component, as described above, WO ₂ is a good conductor and alkali-soluble. Therefore, no debris remains on the surface.

As a matter of course, a single metal W may be used as the inorganic conductive film 14, and a W-based compound may be used. As the W-based compound, any kind of W-based compound can be used as long as it can be used for charge-up, but tungsten oxide is preferable in the investigation of the inventor.
The metal W alone is soluble in an alkaline solution and is excellent in conductivity. Among tungsten oxides, W ₂ O ₃ (III), WO ₂ (IV) and WO ₃ (VI) are qualified in terms of conductivity. They are soluble in alkaline solutions.

  Here, “main component” in the present specification indicates that the compound is the most abundant of the 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 a main component in the inorganic conductive film 14.

The film thickness of the inorganic conductive film 14 is preferably 1 nm to 10 nm, and more preferably 2 nm to 5 nm. As the reason, as described above, it is possible to keep the formation state of the inorganic conductive film 14 in good condition, and it becomes possible to perform sufficient charge removal. In addition, it does not require much time and effort for producing the inorganic conductive film 14, and moreover, it is possible to suppress the risk that the residue when removing the inorganic conductive film 14 becomes foreign matter. In addition, electron beam irradiation can be favorably performed on the resist film 12 through the inorganic conductive film.
Note that the film thickness may be appropriately adjusted 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 the substance is higher than that of a metal film; therefore, the film may be formed in a range of 3 nm to 10 nm. In the case of a metal film of Mo or W (including a surface oxidized state), since the specific resistance of the substance is relatively low, the film may be 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 the reason, as described above, it is possible to suppress the possibility that the electrons flowing through the inorganic conductive film 14 affect the resist film to lower the sensitivity. In addition, it is possible to provide a sufficient charge removing ability, and for example, it is possible to surely form a pattern of 70 nm pitch.

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

<2. Method of Manufacturing Mask Blank 1 with Resist Film>
Next, a method of manufacturing the mask blank 1 with a resist film in the present embodiment will be described with reference to FIG. FIG. 3 is a schematic cross-sectional view showing a method of manufacturing the mask blank 1 with a resist film in the present embodiment. In addition, the contents of the following steps are <1. There is also a portion overlapping with the contents described in the resist blank with mask film 1>. Therefore, for the contents not described below, <1. It is as having demonstrated by mask blank 1 with resist film>.

  In this embodiment, an example is shown 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 process with thin film, but the thin film 11 is formed in advance. An embodiment in which the mask blank 5 is prepared and the resist film 12 is formed thereon is also included in the embodiment 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. A known method may be used as a specific configuration and preparation method. In the present embodiment, a case in which the light transflective film 110 and the light shielding film 111 are provided on the substrate 10 made of quartz glass is used as the mask blank 5 will be described.

2-B) Resist Film Forming Step In this step, a 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 one example, after the main surface of the thin film 11 is subjected to HMDS treatment, a resist solution is applied on the main surface of the thin film 11 by spin coating, and baking treatment is performed. Thus, a resist film 12 is formed 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 of an organic conductive polymer on the main surface of the resist film 12. As a specific method, a known method may be used. As one 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 to cover the resist film 12. Note that this step is not essential in the present invention, as described in the item of 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 evaporation may be used. However, preferred is sputtering deposition as described above. 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.

By the above, the mask blank 1 with a resist film in this embodiment is produced. Of course, the cleaning / drying steps and the like necessary for the production of the mask blank 1 with a resist film may be appropriately performed.
The transfer mask may be manufactured from the above-described mask blank 1 with a resist film. After performing exposure (drawing) by electron beam irradiation corresponding to a predetermined pattern to the above-mentioned mask blank 1 with a resist film, a pattern formation process of forming a resist pattern by development is performed. In addition to the above-described method, a known method may be used as a specific method of diselectrification. Finally, a thin film 11 having a predetermined uneven pattern is produced. Here, the pattern formation step may refer to the formation of a resist pattern, or may be further advanced from that to refer to the formation of an uneven pattern on the thin film 11 and the substrate 10 itself. . Also in this case, the cleaning / drying steps and the like necessary for producing the transfer mask may be appropriately performed.

Next, the present invention will be specifically described by way of examples. Of course, the present invention is not limited to the following examples. In addition, the matter as described in Unexamined-Japanese-Patent No. 2013-257593 employ | adopts the matter which is not specified.
In Example 1, the inorganic conductive film 14 mainly composed of Mo was formed directly on the main surface of the resist film 12.
In the second embodiment, as in the present embodiment, the organic conductive film 13 is formed on the main surface of the resist film 12 and the main surface of the organic conductive film 13 is mainly composed of Mo. The film 14 was formed.
In Example 3, the inorganic conductive film 14 containing Mo as a main component 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, different from Example 2 according to Example 2, an inorganic conductive film 14 containing W as a main component was formed.
Comparative Example 1 shows an example in which the inorganic conductive film 14 is not provided in Example 2.

Example 1
(Preparation of sample)
2-A) Substrate with Thin Film (Mask Blank) Preparation Step Translucent substrate 10 (hereinafter referred to as light transmission) 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 (Also referred to as a substrate 10).

First, the light transflective film 110 was formed on the light transmitting 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) as a sputtering target (mol% ratio Mo: Si = 10: 90) 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 : MoSiN film (lower layer) was formed to a film thickness of 69 nm by DC power of 3.0 kW.
Next, the substrate 10 on which the MoSiN film was formed was subjected to heat treatment in the atmosphere at a heating temperature of 450 ° C. and a heating time of 1 hour using a heating furnace. The MoSiN film had a 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.
Single-wafer DC sputtering system, using chromium (Cr) target, mixed gas of argon (Ar), carbon dioxide (CO ₂ ), nitrogen (N ₂ ) and helium (He) (flow ratio Ar: CO ₂ : N) _{2: He = 20: 35:} 10: 30, pressure = 0.2 Pa) reactive sputtering (DC sputtering as a sputtering gas: the DC power 1.7 kW), was formed CrOCN film thickness 30 nm (first Light shielding film 111a).
Furthermore, using the same chromium (Cr) target, a mixed gas of argon (Ar) and nitrogen (N ₂ ) (flow ratio Ar: N ₂ = 25: 75, pressure = 0.1 Pa) is used as a sputtering gas to react CrN film was formed to a thickness of 4 nm (second light shielding film 111b) by reactive sputtering (DC sputtering: DC power: 1.7 kW).
Furthermore, using the same chromium (Cr) target, a mixed gas of argon (Ar), carbon dioxide (CO ₂ ), nitrogen (N ₂ ) and helium (He) (flow ratio Ar: CO ₂ : N ₂ : He A chromium-rich CrOCN film was formed to a film thickness of 14 nm by reactive sputtering (DC sputtering: DC power: 1.7 kW) using a sputtering gas of: 20: 35: 5:30, pressure: 0.2 Pa Three shading film 111c).
According to the above procedure, a light shielding film 111 of a chromium-based material having a three-layer structure of the lowermost layer composed of CrOCN, the lower layer composed of CrN, and the lower layer composed of CrN from the phase shift film side was formed in a total film thickness of 48 nm.
The thin film-coated substrate 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). The surface reflectance of the light shielding film 111 was 20% with respect to the wavelength of exposure light (λ = 193 nm).

2-B) Resist Film Forming Step A chemical amplification type positive resist (PRL 009S manufactured by Fujifilm Electromaterials Co., Ltd.) is applied to the surface of the thin film 11 by spin coating, and then baked at 190 ° C. for 60 seconds for a film thickness of 120 nm. A resist film 12 was formed.

2-D) Inorganic Conductive Film Forming Step A MoO _X film having a thickness of 5 nm was formed thereon as the inorganic conductive film 14. Specifically, a molybdenum-molybdenum (Mo) target is used, and a mixed gas of argon (Ar) and oxygen (O ₂ ) (flow ratio Ar: O ₂ = 90: 10, pressure = 0.1 Pa) is used as a sputtering gas to react Film formation was performed by reactive sputtering (DC sputtering: DC power 1.5 kW).

Example 2
In the present example, as in the present embodiment, the organic conductive film 13 is formed on the main surface of the resist film 12, and the main surface of the organic conductive film 13 is mainly composed of Mo. The film 14 was formed. The other steps were the same as in Example 1, so only the method for producing the organic conductive film 13 will be described.

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

2-D) Inorganic Conductive Film Forming Step A MoO _X film having a thickness of 3 nm was formed thereon as the inorganic conductive film 14. Specifically, using a molybdenum (Mo) target, argon (Ar) (pressure = 0.1 Pa) was used as a sputtering gas (DC sputtering: DC power 1.5 kW) to form a film.
The mask blank 1 with a resist film in this example was produced using the above-mentioned method.
The contents were the same as Example 1 except for the above contents.

Example 3
In the present 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 other conditions were the same as in Example 1.

2-D) Inorganic Conductive Film Forming Step A Mo film was formed thereon to a thickness of 3 nm. Specifically, using a molybdenum (Mo) target, 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 to a thickness of 3 nm. Specifically, a molybdenum (Mo) target is used, and a mixed gas of argon (Ar) and oxygen (O ₂ ) (flow ratio Ar: O ₂ = 90: 10, pressure = 0.1 Pa) is used as a sputtering gas, and the reactivity The film was formed by sputtering (DC sputtering: DC power 1.5 kW).
The mask blank 1 with a resist film in this example was produced using the above-mentioned method.

Example 4
In the present example, according to Example 2, unlike in Example 2, an inorganic conductive film 14 containing W as a main component was formed. Then, an alkaline solution was used for pre-rinsing for removing the inorganic conductive film 14. The other processes were the same as in Example 1. Therefore, only the method for producing the inorganic conductive film 14 will be 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. Specifically, a tungsten (W) target is used, and a mixed gas of argon (Ar) and oxygen (O ₂ ) (flow ratio Ar: O ₂ = 90: 10, pressure = 0.1 Pa) is used as a sputtering gas to react Film formation was performed by reactive sputtering (DC sputtering: DC power 1.5 kW).
The mask blank 1 with a resist film in this example was produced using the above-mentioned method.

Comparative Example 1
In the present comparative example, a sample was produced 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 blanks 5 of Examples 1 to 4 and Comparative Example 1 using an electron beam lithography system 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 line to space was 1: 1. After drawing, it was heated at 130 ° C. for 600 seconds.
Then, pre-rinse was performed about Examples 1-4, and the inorganic conductive film 14 was removed by the pure water (ion-exchange water) or an alkaline solution. It was followed by development. The development was performed by supplying a developer (THAM: tetramethyl ammonium hydroxide) to the substrate 10 at 5 mL / sec.
Then, drying rotation was performed for 60 seconds at high speed rotation, and allowed to dry naturally. The steps after the removal of the resist pattern were not performed.
The resist pattern of the sample thus obtained was observed with an electron microscope, and in Examples 1 to 4, it was possible to form a pattern at a predetermined position well at half pitch of all the sizes. From this, it was found that in Examples 1 to 4, the charging at the time of forming the resist pattern was rapidly eliminated.
On the other hand, in Comparative Example 1, the phenomenon that the position of the actually formed pattern deviates from the predetermined position to be drawn when the half pitch is smaller than 70 nm occurs. From this, it was found that, even when the organic conductive film 13 was formed, when the pattern size was narrow, the charge at the time of electron beam drawing could not be eliminated.

1 ... ... Mask blank 5 with resist film ... ... Mask blank 10 ... Substrate 11 ... Thin film 110 ... Light semi-transmissive film 111 ... Light shielding film 111 a ... First light shielding film 111 b ... Second light shielding film 111 c ... 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 contains at least one of molybdenum and tungsten,
A resist blank with a resist film, wherein a water-soluble resin film is formed between the resist film and the inorganic conductive film.   The resist blank with a resist film according to claim 1, wherein the water-soluble resin film is an organic conductive film composed of a conductive polymer.   The film thickness of the said inorganic conductive film is 1 nm-10 nm, The mask blank with a resist film of Claim 1 or 2 characterized by the above-mentioned.   The resist blank with a resist film according to any one of claims 1 to 3, wherein the inorganic conductive film entirely contains at least one of an oxide of molybdenum and an oxide of tungsten. According to any one of the inorganic conductive film _{MoO 3, Mo 2 O 5,} MoO 3, W 2 O 3, WO 2, and from the claims 1, characterized in that it comprises at least one of WO ₃ 3 Mask blank with resist film. It is a manufacturing method of a mask blank with a resist film, and
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 of manufacturing a mask blank with a resist film, comprising:   The method for producing a resist 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 film thickness of the said water-soluble resin film is 1 nm-10 nm, The manufacturing method of the mask blank with a resist film of Claim 6 or 7 characterized by the above-mentioned.   The method according to any one of claims 6 to 8, wherein the inorganic conductive film entirely contains at least one of an oxide of molybdenum and an oxide of tungsten. The inorganic conductive film according to any one of claims 6 to 9, wherein the inorganic conductive film contains at least one of MoO ₃ , Mo ₂ O ₅ , MoO ₃ , W ₂ O ₃ , WO ₂ , and WO _3. Method of mask blank with resist film of   The method for producing a mask blank with a resist film according to any one of claims 6 to 10, wherein the inorganic conductive film forming step is performed using sputtering film formation. The manufacturing method of the transfer mask which has a pattern formation process of forming an uneven | corrugated pattern with respect to the thin film at least among the said mask blanks using the mask blank with a resist film in any one of Claims 1-5.

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