KR20110055436A - Method for reproducing substrate, method for manufacturing mask blak, method for manufacturing substrate having a multi layer reflection film and method for manufacturing reflection type mask blank - Google Patents

Abstract

PURPOSE: A method for regenerating a substrate, a method for manufacturing a mask blank, a method for manufacturing a substrate with a multilayered reflective film, and a method for manufacturing a reflective mask blank are provided to reduce the damage of the substrate after a thin film is eliminated by eliminating the thin film using a non-excited material containing a specific fluoric compound. CONSTITUTION: A mask blank thin film or a transferring mask thin film is attached to a substrate(41). The thin film is eliminated by being contacted with non-excited material containing the compound of fluorine and one of chlorine, brome, iodine, and xenon. The thin film is single layer or multi-layered. A layer in contact with the substrate is based on dry-etchable material with fluorine-based gas.

Description

TECHNICAL FOR REPRODUCING SUBSTRATE, METHOD FOR MANUFACTURING MASK BLAK, METHOD FOR MANUFACTURING SUBSTRATE HAVING A MULTI LAYER REFLECTION FILM AND METHOD FOR MANUFACTURING REFLECTION TYPE MASK BLANK}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for regenerating a substrate by removing thin films such as mask blanks, a method for producing a mask blank, a method for producing a substrate having a multilayer reflective film, and a method for producing a reflective mask blank.

Generally, in the manufacturing process of a semiconductor device, fine pattern formation is performed using the photolithographic method. In addition, a transfer mask called several photomasks is used for formation of this fine pattern. This transfer mask generally forms a fine pattern made of a metal thin film or the like on a light-transmissive glass substrate, and the photolithography method is also used in the production of the transfer mask.

In the manufacture of the transfer mask by the photolithography method, a mask blank having a thin film (for example, a light shielding film) for forming a transfer pattern (mask pattern) on a light transmissive substrate such as a glass substrate is used. The manufacturing of the transfer mask using the mask blank includes a drawing step of performing a desired pattern drawing on the resist film formed on the mask blank, a developing step of developing the resist film after drawing to form a desired resist pattern; The resist pattern is used as a mask to perform an etching step of etching the thin film, and a step of peeling and removing the remaining resist pattern. In the above development step, after the desired pattern drawing is performed on the resist film formed on the mask blank, a developer is supplied to dissolve a portion of the resist film available to the developer to form a resist pattern. In the above etching step, the resist pattern is used as a mask, and portions of the thin film on which the resist pattern is not formed are removed by dry etching or wet etching, thereby forming a desired mask pattern on the light transmissive substrate. do. In this way, the transfer mask is completed.

As a kind of transfer mask, a halftone phase shift mask is known in addition to a binary mask having a light shielding film pattern made of a chromium-based material on a conventional light-transmissive substrate. This halftone phase shift mask is a structure which has a phase shift film on a translucent board | substrate, and this phase shift film is a thing of intensity | strength (for example, 1%-20% with respect to an exposure wavelength) of intensity | strength which does not substantially contribute to exposure. It transmits and gives a predetermined phase difference, For example, the material containing a molybdenum silicide compound, etc. are used. Moreover, the binary mask which uses the material containing the silicide compound of metals, such as molybdenum, as a light shielding film is also used.

By the way, in recent years, competition for reducing the cost of electronic components such as semiconductor devices has intensified, while suppressing the manufacturing cost of the transfer mask is also an important problem. From such a background, after forming a thin film for pattern formation on a board | substrate, the mask blank in which the surface defect was discovered, or the transfer defect in which the pattern defect which was difficult to fix was found in the transfer mask produced using the mask blank. There is a demand for a method of regenerating a substrate by peeling off a thin film from the substrate without discarding the mask as a defective product.

As a method of removing the thin film on a glass substrate, the method of using the thin film etchant is conventionally common. For example, Japanese Patent Application Laid-Open No. 62-218585 (Patent Document 1) discloses at least one of ammonium hydrogen fluoride, ammonium fluoride, hydrofluoric acid and boric fluoride as an etchant for light-shielding films containing metal silicides such as molybdenum silicide. It is described to use an aqueous solution in which any one of hydrogen peroxide and nitric acid are mixed, and it is possible to remove a thin film containing a metal silicide on a substrate by etching using such an etchant. Moreover, about thin films containing metal silicides, such as molybdenum silicide, it is also possible to remove using hydrofluoric acid.

However, the method of removing the thin film containing metal silicide, such as molybdenum silicide, on a glass substrate using the etchant or hydrofluoric acid described in the said patent document 1 has the following problems.

That is, since the glass, which is a material of the substrate, is soluble to the etchant and hydrofluoric acid described in Patent Document 1, the surface roughness of the substrate surface, on which the deteriorated layer due to turbidity is formed or the smoothness is smoothly polished, is formed on the substrate surface after thin film removal. It is inevitable that damage to the back will occur.

In order to completely remove such damage and regenerate the substrate, it is necessary to regrind and take a lot of polishing extra. Surface polishing of the glass substrate before film-forming is normally performed through the several-step grinding process from coarse polishing to precision polishing. In the case of re-polishing, since it is necessary to take a lot of grinding | polishing excess as mentioned above, it is necessary to return to the initial stage of a several-step polishing process, and since it requires a long time for re-polishing processing, the process load of re-polishing is large, The cost is high. In other words, even if the substrate is regenerated by the conventional method, it is difficult to say that the problem of suppressing the manufacturing cost of the transfer mask is sufficient.

In addition, Japanese Patent Application Laid-Open No. 2002-4052 (Patent Document 2) discloses a deposition gas attached to an inner wall of a reaction vessel in a film forming apparatus for depositing a deposition film such as amorphous silicon on a substrate, including at least ClF ₃ . Or a method of removing the cleaning gas by plasma. However, when plasma is used to increase the cleaning speed, the generation of damage by the plasma is concerned. In substrate regeneration of the mask blank, it is desired to suppress the deterioration of the surface of the substrate after the thin film removal and to suppress the deterioration of the surface roughness. Therefore, when the deposition film adhered to the inner wall of the reaction vessel is simply removed as in Patent Document 2, You can't simply apply the same method to.

In addition, the thin film material of the mask blank is not limited to the metal silicides such as molybdenum silicide described above, and various kinds of thin film materials are known depending on the type of the mask blank, and a release agent (such as an etchant) according to each thin film material is used. It is possible to regenerate the substrate by removing the thin film on the substrate. However, also in the case where these thin film materials are different, it is desirable to be able to regenerate a board | substrate by removing a thin film using the same method if possible. In addition, the thin film of the mask blank is often composed of a plurality of layers. In this case, even when the material of each layer is different, when regenerating the substrate, it is possible that the entire thin film of the plurality of layers can be peeled off from the substrate at once. desirable.

In addition, in recent years, with the miniaturization of patterns in semiconductor devices and the like, high-precision and high-quality transfer masks are required, and expensive blank substrates prepared for high added value are also frequently used in mask blanks for manufacturing such transfer masks. In order to reduce the manufacturing cost of the transfer mask, substrate regeneration of the mask blank has been a more important problem in the past.

Therefore, the 1st objective of this invention is providing the board | substrate regeneration method which can reduce the regeneration cost of a board | substrate because there is little damage of the board | substrate after removal of a thin film, and also the process load of repolishing is small.

The 2nd object of this invention is to provide the manufacturing method of the mask blank which uses the board | substrate recycled by this regeneration method, the manufacturing method of the board | substrate which has a multilayer reflective film, and the manufacturing method of a reflective mask blank.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining, it discovered that the damage of the board | substrate after thin film removal can be reduced by contacting and removing the thin film on a board | substrate to the substance of the nonexcited state containing a specific fluorine-type compound. In addition, the above-described method can reduce the damage of the substrate after thin film removal particularly when the thin film is formed of a material which can be dry-etched with a fluorine-based gas, such as a material containing silicon, for example. Also found.

MEANS TO SOLVE THE PROBLEM This inventor completed this invention as a result of continuing earnest research based on the above-mentioned clarification fact.

Hereinafter, various aspects of this invention are listed.

(Aspect 1)

A method of regenerating a substrate by removing a mask blank including a thin film for pattern formation on a main surface of a substrate made of glass or a transfer mask fabricated using the mask blank, wherein the mask blank or the front surface is removed. The thin film of the mask used is brought into contact with an unexcited state containing an element of any one of chlorine (Cl), bromine (Br), iodine (I), and xenon (Xe) and a compound of fluorine (F). Removing the substrate.

(Aspect 2)

The said thin film consists of a single | mono layer or multiple layers, and the layer which contact | connects at least the said board | substrate is formed from the material which can be dry-etched with a fluorine-type gas, The regeneration method of the board | substrate of aspect 1 characterized by the above-mentioned.

(Aspect 3)

The layer in contact with the substrate is formed of any one of a material containing silicon (Si), a material containing metal and silicon (Si), and a material containing tantalum (Ta). The regeneration method of the board | substrate of Claim.

(Aspect 4)

The said board | substrate consists of synthetic quartz glass, The reproduction method of the board | substrate in any one of aspect 1 to 3 characterized by the above-mentioned.

(Aspect 5)

The thin film for pattern formation is formed on the board | substrate regenerated by the regeneration method of the board | substrate in any one of aspect 1-4, The manufacturing method of the mask blank characterized by the above-mentioned.

(Aspect 6)

A method of regenerating a substrate by removing the multilayer reflective film of a substrate having a multilayer reflective film having a multilayer reflective film having a structure in which a low refractive index layer and a high refractive index layer are alternately laminated on a main surface of a glass substrate. The multilayer reflective film of the substrate having a non-excited state containing a compound of any one of chlorine (Cl), bromine (Br), iodine (I), and xenon (Xe) and fluorine (F) A substrate regenerating method, characterized in that the contact is removed.

(Aspect 7)

The low refractive index layer is made of silicon (Si) and is formed in contact with the main surface of the substrate.

(Aspect 8)

The substrate and reproducing method of the substrate according to the aspect 6 or 7, characterized in that consisting of SiO ₂ -TiO ₂ based low thermal expansion glass.

(Aspect 9)

A multilayer reflective film having a structure in which a low refractive index layer and a high refractive index layer are laminated alternately is formed on a substrate regenerated by the regeneration method of the substrate according to any one of embodiments 6 to 8. Manufacturing method.

(Aspect 10)

On the main surface of the glass substrate, a reflective mask blank or a reflective mask blank including a multilayer reflective film having a structure in which a low refractive index layer and a high refractive index layer are alternately stacked, and an absorber film for pattern formation is used in order. A method of regenerating a substrate by removing the multilayer reflective film of the reflective mask fabricated by using the reflective mask, wherein the reflective mask blank or the multilayer reflective film of the reflective mask is made of chlorine (Cl), bromine (Br) or iodine (I). And a non-excited substance containing an element of any of xenon (Xe) and a compound of fluorine (F) in contact with and removing the substrate.

(Aspect 11)

The low refractive index layer is made of silicon (Si) and is formed in contact with the main surface of the substrate.

(Aspect 12)

The substrate and reproducing method of the substrate according to embodiments 10 or 11, characterized in that consisting of SiO ₂ -TiO ₂ based low thermal expansion glass.

(Aspect 13)

Forming a multilayer reflective film having a structure in which a low refractive index layer and a high refractive index layer were alternately laminated on the substrate regenerated by the regeneration method of the substrate according to any one of Embodiments 10 to 12, and an absorber film for pattern formation in order. The manufacturing method of the reflective mask blank characterized by the above-mentioned.

(Aspect 14)

In the mask blank which comprises the thin film for pattern formation on the main surface of the board | substrate which consists of glass, the said thin film of the mask blank corresponding to the manufacturing method of the imprint mold which etching-processes the said thin film and the said board | substrate by dry etching process is carried out. As a method of removing and regenerating a substrate, the thin film of the mask blank is formed of a compound of any one of chlorine (Cl), bromine (Br), iodine (I), and xenon (Xe) with fluorine (F). A method for regenerating a substrate, characterized in that the material is brought into contact with and removed from an unexcited state.

(Aspect 15)

The said thin film consists of a single | mono layer or multiple layers, and the layer which contact | connects at least the said board | substrate is formed with the material which has tantalum (Ta) as a main component, The regeneration method of the board | substrate of aspect 14 characterized by the above-mentioned.

(Aspect 16)

Said substrate consists of synthetic quartz glass, The regeneration method of the board | substrate of aspect 14 or 15 characterized by the above-mentioned.

(Aspect 17)

The thin film for pattern formation is formed on the board | substrate regenerated by the regeneration method of the board | substrate in any one of aspect 14-16, The manufacturing method of the mask blank characterized by the above-mentioned.

According to the present invention, the glass, which is a material of the substrate, is easy to be etched by dry etching with the fluorine-based gas in the excited state, but hardly etched by the material of the fluorine-based compound in the non-excited state. Damage can be reduced and the reloading process load can be reduced, thereby reducing the regeneration cost of the substrate. Further, according to the present invention, since a high quality substrate can be reproduced at a low cost, it is particularly preferable for regenerating a mask blank substrate using an expensive substrate prepared for high added value.

Further, according to the present invention, by forming a thin film for pattern formation on the substrate regenerated by the regeneration method according to the present invention, a mask blank using a high quality regenerated substrate can be produced in a low cost. A substrate having a multilayer reflective film using a high quality regenerated substrate or a reflective mask by forming a multilayer reflective film having a structure in which a low refractive index layer and a high refractive index layer are alternately stacked, an absorber film for pattern formation, and the like on the substrate. The blank can be made in low cost.

1 is a schematic configuration diagram of a processing apparatus used in a step of removing a thin film.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail.

[First Embodiment]

According to a first embodiment of the present invention, a substrate is formed by removing a mask blank including a thin film for pattern formation on a main surface of a substrate made of glass or the thin film of a transfer mask manufactured by using the mask blank. A method according to the present invention, wherein the thin film of the mask blank or the transfer mask comprises a compound of any one of chlorine (Cl), bromine (Br), iodine (I), and xenon (Xe) with fluorine (F). The method of regenerating the substrate, characterized in that by removing in contact with the non-excited material comprising a.

The mask blank used in this embodiment is a mask blank provided with the thin film for pattern formation on the main surface of a board | substrate, but specifically, the binary mask blank of a structure provided with a light shielding film on the main surface of a board | substrate, a board | substrate The phase shift type mask blank of the structure provided with a phase shift film, or a phase shift film and a light shielding film on the main surface of this is mentioned. Moreover, the mask of the structure provided with the light semitransmissive film which has the characteristic which transmits the light of intensity which does not substantially contribute to exposure, but does not give the phase difference which produces a phase shift effect, or this light semitransmissive film and light shielding film. Blanks. Moreover, the mask blank of the structure which has an etching mask film in the uppermost layer of these mask blanks, etc. are mentioned. In addition, it is applicable also to the mask blank used for the multi-gradation mask used in manufacture of an FPD (flat panel display) device. Examples of the mask blank include a structure in which a light semitransmissive film and a light shielding film are laminated on a glass substrate.

This light shielding film may be a single layer or a plurality of layers (for example, a laminated structure of a light shielding layer and an antireflection layer). In addition, when making a light shielding film into a laminated structure of a light shielding layer and an antireflection layer, you may make it the structure which consists of multiple layers. The phase shift film and the light semitransmissive film may also be a single layer or a plurality of layers.

In this regeneration method, the thin film is mixed with a fluorine-based gas (for example, SF ₆ , CF ₄ , C ₂ F ₆ , CHF ₃ , or the like and He, Ar, N ₂ , C ₂ H ₄ , O _2, etc.). Gas), which is suitable for the regeneration of the substrate of the mask blank formed of a material dry dry etchable. Although the glass substrate is easy to etch to the plasma of the fluorine-type gas which is an excited state used by dry etching, it has the characteristic which is hard to etch to the substance of the fluorine-type compound of a non-excitation state. On the other hand, the material which can be dry-etched with the fluorine-type gas used by a thin film has the characteristic which is easy to etch also about the substance of the fluorine-type compound of a non-excitation state. That is, the material which can be dry-etched with a fluorine-based gas is easy to obtain sufficient etching selectivity with respect to the substance of a fluorine-type compound of a non-excitation state, and the effect which can reduce the damage to a board | substrate by peeling of a thin film is especially easy to be acquired. .

As a material which can be dry-etched with this fluorine-type gas, for example, a material containing silicon (Si), a material containing a transition metal and silicon (Si), a material containing metal and silicon (Si), and tantalum (Ta) ), And the like. As a mask blank using such a material, it is formed by the material containing the binary mask blank and tantalum (Ta) provided with the light shielding film formed by the material containing a transition metal and silicon (Si), for example. A binary mask blank having a light shielding film, a phase shift mask blank having a phase shift film formed of a material containing silicon (Si), or a material containing a transition metal and silicon (Si). have.

As the material containing silicon (Si), a material containing silicon and at least one element of nitrogen, oxygen, and carbon, specifically, silicon nitride, oxide, carbide, oxynitride, carbonate, or carbonic acid Preference is given to materials comprising nitrides.

As the material containing the transition metal and silicon (Si), in addition to the material containing the transition metal and silicon, a material containing at least one element of nitrogen, oxygen and carbon in the transition metal and silicon may be mentioned. have. Specifically, a material containing a transition metal silicide or a nitride, oxide, carbide, oxynitride, carbonate, or carbonate nitride of the transition metal silicide is preferable. Molybdenum, tantalum, tungsten, titanium, chromium, hafnium, nickel, vanadium, zirconium, ruthenium, rhodium, niobium, yttrium, lanthanum, palladium, iron and the like are applicable to the transition metal. Among these, molybdenum is especially preferable.

Moreover, as a material containing the said metal and silicon (Si), besides the material containing a metal and silicon, the material which contains at least 1 element of nitrogen, oxygen, and carbon in metal and silicon is mentioned. The material containing a metal and silicon (Si) includes the material containing said transition metal and silicon (Si). Germanium, gallium, aluminum, indium, tin, etc. are applicable to a metal other than said transition metal.

As the material containing tantalum (Ta), in addition to tantalum alone, a compound of tantalum and other metal elements (for example, Hf, Zr, etc.), tantalum, and at least one of nitrogen, oxygen, carbon, and boron And a material containing TaN, TaO, TaC, TaB, TaON, TaCN, TaBN, TaCO, TaBO, TaBC, TaCON, TaBON, TaBCN, TaBCON, and the like.

In this regeneration method, when a thin film such as a light shielding film in a binary mask blank and a phase shift film in a phase shift mask blank is formed of a plurality of layers, at least the layer in contact with the substrate is dried with a fluorine-based gas. Etchable materials such as the materials containing silicon (Si) described above, materials containing transition metals and silicon (Si), materials containing metals and silicon (Si), and materials containing tantalum (Ta) It is suitable for regeneration of the substrate of the mask blank formed by either of these.

The mask blank substrate is not particularly limited as long as it has transparency to an exposure wavelength to be used, and a synthetic quartz substrate and other glass substrates (for example, soda lime glass, aluminosilicate glass, etc.) may be used. Among them, the synthetic quartz substrate is particularly preferably used because of its higher transparency in the ArF excimer laser or shorter wavelength region.

This regeneration method uses a mask blank including a thin film for pattern formation on the main surface of the substrate as described above, or a thin film of a transfer mask produced by a mask processing technique using the mask blank. ), A method of regenerating a substrate by contacting and removing a non-excited substance containing an element of any one of bromine (Br), iodine (I), and xenon (Xe) and a compound of fluorine (F).

Between the glass substrate and the thin film for pattern formation (especially, a thin film made of a material which can be dry-etched with a fluorine-based gas), the etching of the fluorine-based gas in an excited state or the fluorine-based gas that is excited by irradiation of charged particles In etching, etching selectivity is hardly obtained. On the other hand, with respect to the substance of the fluorine-based compound in the non-excited state, high etching selectivity can be obtained between the glass substrate and the thin film for pattern formation. Moreover, what is necessary is just to make the substance of this non-excitation fluorine-type compound contact in the state of a fluid, and it is especially preferable to make it contact in a gaseous state.

On the other hand, the hydrofluoric acid solution or silicic acid solution containing hydrogen ions has the effect that hydrogen ions break the bond of Si-0 in the glass, so that fluorine and silicon are easily bonded, so that the glass is easy to dissolve. It is difficult to obtain an action effect. In view of this, it is preferable that the substance of the fluorine-based compound in the non-excited state is substantially free of hydrogen.

Examples of the compound (hereinafter, simply referred to as "the compound of the present invention") of an element of any one of chlorine (Cl), bromine (Br), iodine (I), and xenon (Xe) and fluorine (F) (for example) , Compounds such as ClF ₃ , ClF, BrF ₅ , BrF, IF ₃ , IF ₅ , XeF ₂ , XeF ₄ , XeF ₆ , XeOF ₂ , XeOF ₄ , XeO ₂ F ₂ , XeO ₃ F ₂ , or XeO ₂ F ₄ Can be preferably used. Among these, especially ClF ₃ can be used preferably.

As a method of contacting the said mask thin film or the said thin film of the transfer mask produced using the mask blank with the substance of the non-excited state containing the compound of this invention, a mask blank is installed in a chamber, for example, and the chamber The method which introduce | transduces the substance containing the compound of this invention in gas state inside, and replaces the inside of a chamber with the gas is mentioned preferably.

When a substance containing the compound of the present invention is used in the gas state, the compound of the present invention and nitrogen gas, or argon (Ar), helium (He), neon (Ne), krypton (Kr), xenon (Xe), A mixed gas with radon (Rn) or the like (hereinafter simply referred to as argon (Ar) or the like) can be used. When using the substance containing the compound of this invention in gaseous state, the mixed gas of the compound of this invention and argon (Ar) can be used preferably.

Particular restrictions are given to the processing conditions when the thin film of the mask blank or the transfer mask is brought into contact with a non-excited gaseous substance containing the compound of the present invention, for example, gas flow rate, gas pressure, temperature and processing time. Although it is not necessary, it is preferable to select suitably according to the material of a thin film and the number of layers (film thickness) from a viewpoint of obtaining the effect of this invention preferably.

About gas flow rate, when using the mixed gas of the compound of this invention and argon, for example, it is preferable that the compound of this invention is mixed 1% or more by a flow ratio. When the flow rate of the compound of the present invention is smaller than the flow rate ratio, the progress of peeling of the thin film is delayed, and as a result, the processing time is long, and the peeling becomes difficult.

In addition, it is preferable to select suitably the gas pressure in the range of 100-760 Torr, for example. If the gas pressure is lower than the above range, the amount of gas of the compound of the present invention in the chamber itself is too small, the progress of peeling of the thin film is delayed, and as a result, the processing time is long and it is difficult to peel. On the other hand, if the gas pressure is higher than the above range (more than atmospheric pressure), there is a possibility that the gas will flow out of the chamber, and the compound of the present invention also contains a highly toxic gas, which is not preferable.

In addition, it is preferable to select suitably the temperature of gas in 20-500 degreeC, for example. When temperature is lower than the said range, advancing of peeling of a thin film will become slow, As a result, processing time will become long and it will become difficult to peel. On the other hand, when temperature is higher than the said range, peeling advances quickly and processing time can be shortened, but the selectivity of a thin film and a board | substrate becomes difficult to be acquired, and there exists a possibility that a board | substrate damage may increase slightly.

In addition, about processing time, what is necessary is just basically enough time for peeling and removing a thin film from a board | substrate. Although somewhat different depending on the above-described gas flow rate, gas pressure, temperature, or material and film thickness of the thin film, the action of the present invention is preferably obtained when the processing time is in the range of approximately 5 to 30 minutes.

1 is a schematic configuration diagram of a processing apparatus suitable for use in a step of removing the thin film.

In this removal apparatus, the non-excited gas supply is comprised by the gas filling containers 43 and 44, the flow controllers 45 and 46, the blowing nozzle 47, and these connection piping. A processing substrate 41 such as a mask blank is provided on the stage 42 in the chamber 40 of the processing apparatus. Then, for example, the gases in the two types of gas filling vessels 43 and 44 are adjusted by the flow rate controllers 45 and 46, respectively, and then mixed, ejected from the jet nozzle 47, and discharged into the chamber 40. Is introduced. In addition, the gas in the chamber 40 is suitably exhausted after the decontamination process by the exhaust gas processing apparatus 49 via the exhaust pipe 48.

The two kinds of gases are fluorine-based compounds, nitrogen gas, or rare gases such as argon (Ar) when a substance containing a fluorine-based compound is used in the gas state.

The chamber 40 of the said removal apparatus is a horizontal apparatus structure, and is most suitable for sheet | leaf process. On the other hand, as a structure of a chamber suitable for the batch process which processes a large number of board | substrates at one time, the following structures are considered, for example. The chamber is made to have a cylindrical longitudinal length, and a heating device is arranged on the outer periphery of the chamber so that the inside of the chamber can be heated. Further, a longitudinal shelf formed of a heat resistant material such as synthetic quartz is arranged inside the chamber, and a plurality of processing substrates can be arranged vertically in the chamber.

In general, a chromium-based material (Cr, CrO, CrN, CrC, CrON, CrCN, CrOC, CrOCN, etc.) containing no silicon is also used as the thin film for pattern formation of the mask blank. In the case of these thin films, a conventional method for removing chromium-based materials may be used, and the method of supplying the compound of the present invention at high temperature or the compound of the present invention in a gaseous state, and the oxygen (O ₂ ) gas You may use the method of supplying with mixed gas with. In the case of a method of supplying the chromium-based material at a high temperature, as the supply conditions, for example, the concentration of the compound of the present invention in the supply gas is set to 90% or more, more preferably 100%, and the object to be treated. What is necessary is just to make surface temperature of into 280 degreeC-350 degreeC. The treatment time is preferably 5 minutes or more, more preferably 6 minutes or more, the pressure in the chamber is about 1 kPa and the supply gas flow rate is about 300 sccm.

In a binary mask blank having a thin film made of a material containing a transition metal and silicon as a light shielding film, a thin film of chromium-based material may be used as the etching mask film on the light shielding film. Moreover, in the phase shift type mask blank which makes a thin film which consists of a material containing a transition metal and silicon as a phase shift film, the thin film of a chromium system material may be used as a light shielding film for forming a light shielding band on a phase shift film. Further, in a mask blank in which a thin film made of a material containing a transition metal and silicon is used as a light semitransmissive film, a thin film of chromium-based material may be used as a light shielding film for forming a light shielding band on the light semitransmissive film. Moreover, there is also a mask blank of the structure which laminated | stacked the thin film which consists of a material which can be dry-etched with a fluorine-type gas as an etching mask film on the light shielding film of chromium system material. In these cases, removing the thin film of chromium-based material may use the above method or a conventional method of removing the chromium-based material.

According to this regeneration method, a thin film, such as a mask blank, is brought into contact with a material in a non-excited state (preferably in a non-excited gas state) containing a compound of the present invention, thereby producing a glass substrate (especially a synthetic quartz substrate). Since high etching selectivity is obtained between them, the damage of the board | substrate after removal of a thin film can be reduced.

Thus, after removing a thin film from a mask blank, the surface of a board | substrate is precisely grind | polished for a short time, and it can recover to the surface roughness of the substantially smooth board | substrate before thin film removal. In this regeneration method, since the damage to the surface of the substrate due to the removal of the thin film is minimal, the polishing extra in the case of regrinding is minimized, and the process returns to the final stage (precision polishing) in the plural steps of the polishing process from coarse polishing to fine polishing. It becomes possible to go. Therefore, the process load of repolishing also becomes small, and the regeneration cost of a board | substrate can be reduced and a high quality board | substrate can be reproduced further. As described above, this regeneration method is capable of regenerating high quality substrates at low cost, and is therefore particularly suitable for regeneration of mask blanks using expensive substrates prepared for high added value.

Moreover, the manufacturing method of the mask blank using the board | substrate recycled by this regeneration method can also be provided. That is, a mask blank using a high quality regenerated substrate can be produced in a low cost by forming a thin film for pattern formation on the substrate regenerated by this regeneration method using, for example, sputtering film formation. have.

Second Embodiment

According to a second embodiment of the present invention, a substrate having a multilayer reflective film having a multilayer reflective film having a structure in which a low refractive index layer and a high refractive index layer are alternately stacked on a main surface of a substrate made of glass is removed. A method of regenerating the fluorine, wherein the multilayer reflective film of the substrate having the multilayer reflective film is any one of chlorine (Cl), bromine (Br), iodine (I), and xenon (Xe). A method of regenerating a substrate, characterized in that the substance is brought into contact with and removed from a substance in a non-excited state containing a compound of the compound.

In recent years, in the semiconductor industry, with the miniaturization of semiconductor devices, EUV lithography, which is an exposure technique using extreme ultraviolet (hereinafter, referred to as EUV) light, is promising. Here, EUV light refers to the light of the wavelength band of a soft X-ray region or a vacuum ultraviolet-ray region, and is specifically, light whose wavelength is about 0.2-100 nm. Reflective masks have been proposed as masks used in this EUV lithography. In such a reflective mask, a multilayer reflective film for reflecting exposure light is formed on a substrate, and an absorber film for absorbing exposure light is formed on the multilayer reflective film in a pattern shape.

The substrate having the multilayer reflective film includes a reflective mask blank for manufacturing the reflective mask, that is, a multilayer reflective film that reflects exposure light on the substrate, and an absorber film for pattern formation that absorbs the exposure light in order. It can use as a board | substrate for reflective mask blanks. After the multilayer reflective film is formed on the substrate, the substrate having the multilayer reflective film whose defects under the film are found by surface defect inspection cannot be used as the substrate for the reflective mask blank, so that the multilayer reflective film is removed once. It is desired to regenerate the substrate.

The multilayer reflective film is a multilayer film obtained by alternately stacking a low refractive index layer and a high refractive index layer. Generally, a thin film of a heavy element or a compound thereof and a thin film of a light element or the compound are alternately stacked about 40 to 60 cycles. Multilayer films are used.

For example, as a multilayer reflective film for EUV light having a wavelength of 13 to 14 nm, a Mo / Si periodic laminated film in which an Mo film and a Si film are alternately stacked for about 40 cycles is preferably used. In addition, as the multilayer reflective film used in the EUV light region, 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 films, Si / Ru / Mo / Ru periodic multilayer films, and the like. What is necessary is just to select a material suitably by exposure wavelength.

Further, in the low as the glass substrate, in order to prevent distortion of a pattern caused by heat during exposure, 0 ± 1.0 × 10 ^-7 / ℃ within the range of, more preferably 0 ± 0.3 × 10 ^-7 / range ℃ A material having a coefficient of thermal expansion is preferably used, and as a material having a low coefficient of thermal expansion in this range, for example, amorphous glass, SiO ₂ -TiO ₂ -based glass, quartz glass, or crystallized glass, crystallized precipitated β quartz solid solution Glass or the like can be used. In addition, a substrate having high smoothness and flatness is preferable in order to obtain high reflectivity and high reflection accuracy. In particular, it is preferable to have the smooth surface (smoothness in 10 micrometer x 10 micrometer area) of 0.15 nmRq or less, and the flatness (flatness in 142 mm x 142 mm area) of 50 nm or less. In addition, the unit Rq which shows smoothness is a root mean square roughness, and can be measured by atomic force microscope. In addition, flatness is a value indicating the warpage (deformation amount) of the surface shown in TIR (Total Indicated Reading), and the plane determined by the least square method on the basis of the substrate surface is referred to as a superplane, It is the absolute value of the elevation difference between the highest position of the substrate surface above and the lowest position of the substrate surface below the hyperplane.

In this regeneration method, for example, the low refractive index layer, such as the Mo / Si periodic lamination film, is made of silicon (Si) and regenerates a substrate of a substrate having a multilayer reflective film formed in contact with the main surface of the substrate. It is preferable to having. In addition, this regeneration method is suitable for regenerating a substrate of a substrate having a multilayer reflective film, for example, in which a substrate such as SiO ₂ -TiO ₂ -based glass is made of low thermal expansion glass. In particular, in the case of SiO ₂ -TiO ₂ -based low thermal expansion glass, when the multilayer reflective film on the main surface of the substrate is to be peeled off with a hydrofluoric acid solution or a silicic acid solution, there is a big problem that the surface roughness is greatly deteriorated because Ti is released from the substrate. In particular, this recycling method is available.

Even in a substrate having a multilayer reflective film, the substrate can be regenerated by bringing the multilayer reflective film of the substrate having the multilayer reflective film into contact with and removing a substance in a non-excited state containing the compound of the present invention.

In the present embodiment, as a compound, that is, a compound of any one of chlorine (Cl), bromine (Br), iodine (I), and xenon (Xe) with fluorine (F), the compound of the first embodiment described above As is the case, for example, ClF ₃ , ClF, BrF ₅ , BrF, IF ₃ , IF ₅ , XeF ₂ , XeF ₄ , XeF ₆ , XeOF ₂ , XeOF ₄ , XeO ₂ F ₂ , XeO ₃ F ₂ , or may be preferably used a compound such as XeO ₂ F _4, can be particularly preferably used a ClF _3.

As a method of bringing a multilayer reflective film into contact with a material in a non-excited state containing a compound of the present invention, a mask blank is provided in the chamber and a material containing the compound of the present invention is provided in the chamber, as in the first embodiment described above. The method of introduce | transducing in a gas state and replacing the inside of a chamber with the gas is mentioned preferably. In addition, similarly to the first embodiment described above, the multilayer reflective film on the glass substrate may be removed using the processing apparatus shown in FIG. 1. When using the substance containing the compound of this invention in gaseous state, the mixed gas of the compound of this invention, nitrogen gas, or argon (Ar) etc. can be used. In that case, it is preferable to use the mixed gas of the compound of this invention and argon (Ar).

Preferred treatment conditions in the case where the multilayer reflective film is brought into contact with a non-excited gaseous substance containing the compound of the present invention, for example, preferred conditions of gas flow rate, gas pressure, temperature, and treatment time, are described in the first embodiment described above. Although it is almost the same as the case of a form, it is preferable to select suitably according to the material of a multilayer reflective film, and the number of layers (film thickness).

According to this regeneration method, a high etching selectivity is obtained between a glass substrate (especially a low thermally expandable glass substrate) by contacting a multilayer reflective film of the substrate having the multilayer reflective film with a non-excited material containing the compound. As a result, damage to the substrate after removal of the multilayer reflective film can be reduced.

In this manner, after the multilayer reflective film is removed from the substrate having the multilayer reflective film, the surface of the substrate is re-polished to restore the surface roughness of the substantially smooth substrate before the multilayer reflective film is removed. Since this regeneration method has little damage to the surface of the substrate due to the removal of the multilayer reflective film, the polishing extra when re-polishing is minimal, and the final step (precision polishing) in the plural steps of the polishing process from coarse polishing to fine polishing is performed. It is possible to go back. Therefore, the process load of repolishing also becomes small, and the regeneration cost of a board | substrate can be reduced and a high quality board | substrate can be reproduced further. In addition, this regeneration method can reproduce high quality substrates at low cost, and is therefore particularly suitable for substrate regeneration of a substrate having a multilayer reflective film using an expensive substrate prepared for high added value.

Moreover, the manufacturing method of the board | substrate which has a multilayer reflective film using the board | substrate recycled by this regeneration method can also be provided. By forming, on the substrate regenerated by this regeneration method, for example, a DC magnetron sputtering method or an ion beam sputtering method, a multilayer reflective film having a structure in which a low refractive index layer and a high refractive index layer are alternately laminated, A substrate having a multilayer reflective film using a high quality recycled substrate can be produced in a low cost.

This regeneration method is suitable not only for regenerating the substrate of the substrate having the multilayer reflective film described above, but also for regenerating the substrate of the reflective mask blank. That is, by using a reflective mask blank or a reflective mask blank having a multilayer reflective film having a structure in which a low refractive index layer and a high refractive index layer are alternately laminated on a main surface of a substrate, and an absorber film for pattern formation in that order The substrate can be regenerated by removing the multilayer reflective film of the produced reflective mask by contacting and removing a substance in a non-excited state containing the compound.

The absorber film has a function of absorbing, for example, EUV light, which is exposure light. For example, a material containing tantalum (Ta) alone or Ta as a main component is preferably used. As a material containing Ta as a main component, a material containing Ta and B, a material containing Ta and N, a material containing Ta and B, and a material containing any one of O and N, and a material containing Ta and Si , Material containing Ta and Si and N, material containing Ta and Ge, material containing Ta and Ge and N, material containing Ta and Hf, material containing Ta and Hf and N, Ta and Hf A material containing and O, a material containing Ta and Zr, a material containing Ta, Zr and N, a material containing Ta, Zr and O, and the like are used.

Further, in order to protect the multilayer reflective film, a protective film or a buffer film is usually formed between the multilayer reflective film and the absorber film. As the material of the protective film, ruthenium compounds other than silicon, and ruthenium compounds containing at least one element of niobium, zirconium, and rhodium in ruthenium are used. As the material of the buffer film, the above chromium-based materials are mainly used.

According to this reproducing method, in the case of such a reflective mask blank or a reflective mask, it is possible to remove the multilayer reflective film and the absorber film (the protective film and the absorber film in the case of having a protective film) stacked thereon together.

Even when the substrate of the reflective mask blank or the reflective mask is regenerated, when a substance containing the compound of the present invention is used in a gas state, a mixed gas of the compound of the present invention and nitrogen gas or argon (Ar) or the like is used. It is available. Even when reproducing the substrate of the reflective mask blank or the reflective mask, the mixed gas of the compound of the present invention described above and argon (Ar) can be preferably used. Preferred treatment conditions in the case of bringing a multilayer reflective film such as a reflective mask blank into contact with a non-excited gaseous substance containing the compound of the present invention, for example, preferred conditions of gas flow rate, gas pressure, temperature and treatment time This is almost the same as in the case of the substrate having the multilayer reflective film described above.

In addition, the reflective mask blank and the reflective mask of the structure which used the chromium system material in the absorber film | membrane, or the structure which formed the buffer film of the chromium system material are removed, The removal of the absorber film | membrane of a chromium system material and a buffer film is the said method, The conventional method for removing chromium-based materials may be used.

According to this regeneration method, a high etching selectivity is obtained between a glass substrate (especially a low thermally expandable glass substrate) by bringing a multilayer reflective film such as the reflective mask blank into contact with a non-excited state containing a compound of the present invention. Therefore, damage to the substrate after removal of the multilayer reflective film and the laminated film (absorber film or protective film and absorber film) thereon can be reduced. In this regeneration method, since the damage on the surface of the substrate due to removal of the multilayer reflective film or the like is small, the reloading process load is also reduced, the regeneration cost of the substrate can be reduced, and the high quality substrate can be regenerated.

Moreover, the manufacturing method of a reflective mask blank using the board | substrate recycled by this regeneration method can also be provided. That is, a multilayer reflective film having a structure in which a low refractive index layer and a high refractive index layer are alternately laminated is formed on a substrate regenerated by this regeneration method, for example, by using a DC magnetron sputtering method or an ion beam sputtering method. By forming a protective film or an absorber film (or buffer film and an absorber film) for pattern formation on the substrate by the magnetron sputtering method or the like, a reflective mask blank using a high quality regenerated substrate can be produced at low cost.

In the structure of the reflective mask blank or the reflective mask to be treated, a chromium-based material is used as the protective film on the multilayer reflective film, and a material other than chromium-based material (such as tantalum or tantalum as a main component) in the absorber film. When is used, it is also possible to remove only the absorber film. In this case, the concentration (concentration at the gas flow rate ratio) of the compound of the present invention in the supply gas may be 80% or more, more preferably 90% or more, and the surface temperature of the absorber film may be 180 ° C to 220 ° C. The treatment time is preferably 5 minutes or more, more preferably 7 minutes or more, and the pressure in the chamber is preferably 490 to 510 Torr. Thereby, the board | substrate which has a multilayer reflective film can be reproduced from a reflective mask blank or a reflective mask. In addition, a reflective mask blank can be manufactured by forming an absorber film again on the board | substrate which has this reproduced multilayer reflective film.

[Third Embodiment]

According to a third embodiment of the present invention, in a mask blank including a thin film for pattern formation on a main surface of a substrate made of glass, a method for producing an imprint mold which etches the thin film and the substrate by dry etching. A method of regenerating a substrate by removing the thin film of the mask blank corresponding to the above method, wherein the thin film of the mask blank is formed of chlorine (Cl), bromine (Br), iodine (I), and xenon (Xe). A method of regenerating a substrate, characterized in that it is brought into contact with a substance in an unexcited state containing a compound of any element and fluorine (F).

In the production of an imprint mold (stamper) used for forming a fine circuit pattern of a magnetic layer in a magnetic recording medium used for a fine circuit pattern of a semiconductor device, an optical component having an optical function added to the fine pattern, a hard disk drive, or the like, the synthesis is performed. The mask blank provided with the thin film for pattern formation on glass substrates, such as a quartz glass, is used. A desired resist pattern is formed on the mask blank, and the thin film is etched using the resist pattern as a mask to form a thin film pattern (mask pattern), and the substrate is etched using the thin film pattern as a mask. The mold for imprint is produced by forming a level | step difference pattern in a translucent board | substrate.

This regeneration method is also suitable for regeneration of a substrate of a mask blank corresponding to such a method for producing an imprint mold.

This regeneration method is particularly suitable for regeneration of a mask blank substrate in which a thin film of the mask blank is composed of a single layer or a plurality of layers, and at least a layer in contact with the substrate is formed of a material containing tantalum (Ta) as a main component. desirable. As such a mask blank, the said thin film consists of a laminated film of at least an upper layer and a lower layer, for example, the upper layer is formed of the material which has Cr as a main component, and the lower layer is formed of the material which has tantalum (Ta) as a main component, Moreover, the mask blank etc. which these thin films can be etched by the dry etching process using a chlorine gas are mentioned as an example.

As a material containing tantalum as a main component, for example, a Ta compound such as TaHf, TaZr, TaHfZr, or a Ta compound thereof is used as a base material. For example, a material such as B, Ge, Nb, Si, C, or N is added. Materials and the like. However, a material containing Ta as a main component has a property of easily oxidizing when it comes in contact with a gas containing oxygen. A material based on Ta, except for materials containing TaHf, TaZr, and TaHfZr as a main component, can be etched by both a chlorine-based gas in an excited state and a fluorine-based gas in an excited state, but a material based on oxidized Ta is in an excited state. In dry etching using a chlorine-based gas, etching becomes difficult, and only etching is possible with the fluorine-based gas in an excited state. In this case, in the fluorine-based gas, the etching selectivity with the glass substrate becomes difficult, and the damage of the glass substrate after peeling becomes large, so the effect of the present invention is very large.

In addition, although the material which has TaHf, TaZr, and TaHfZr as a main component can be etched by the chlorine gas of an excited state, it is difficult to etch with the fluorine gas of an excited state. These materials are also easy to oxidize, and if oxidized, etching becomes difficult even with an chlorine gas in an excited state. In this case, the etching selectivity by the chlorine-based gas becomes difficult to be obtained between the glass substrate and the damage of the glass substrate after peeling becomes large, so the effect of the present invention is very large.

As the substrate for the mask blank, a synthetic quartz substrate and other glass substrates (for example, soda lime glass, aluminosilicate glass, etc.) are used. Among them, the synthetic quartz substrate is particularly preferably used.

Also in the mask blank corresponding to the manufacturing method of the imprint mold of this embodiment, a board | substrate can be regenerated by making the thin film of a mask blank contact and remove the non-excited state containing the compound of this invention.

The compounds of the present invention used in the present embodiment, that is, the compounds of any one of chlorine (Cl), bromine (Br), iodine (I), and xenon (Xe) and fluorine (F) are described above. As in the case of the first embodiment, for example, ClF ₃ , ClF, BrF ₅ , BrF, IF ₃ , IF ₅ , XeF ₂ , XeF ₄ , XeF ₆ , XeOF ₂ , XeOF ₄ , XeO ₂ F ₂ , XeO ₃ F _2, or may be preferably used a compound such as XeO ₂ F _4, can be particularly preferably used a ClF _3.

Also in this embodiment, as a method of contacting the thin film of a mask blank to the substance of the non-excitation state containing the compound of this invention, the mask blank is provided in a chamber similarly to 1st Embodiment mentioned above, and this invention is provided in the chamber. The method of introduce | transducing the substance containing the compound of in gas state, and replacing the inside of a chamber with the gas is mentioned preferably. In addition, similarly to the first embodiment described above, the thin film of the mask blank may be removed using the processing apparatus shown in FIG. 1. When using the substance containing the compound of this invention in gaseous state, the mixed gas of the compound of this invention, nitrogen gas, or argon (Ar) etc. can be used. In this case, a mixed gas of the compound of the present invention and argon (Ar) can be preferably used. Preferred treatment conditions in the case where the thin film of the mask blank is brought into contact with an unexcited gaseous substance containing the compound of the present invention, for example, preferred conditions of gas flow rate, gas pressure, temperature, and treatment time, are described in Although it is almost the same as the case of 1 Embodiment, it is preferable to select suitably according to the material of a thin film and the number of layers (film thickness).

According to this regeneration method, a substrate made of glass (particularly a synthetic quartz glass substrate) is obtained by contacting and removing a thin film of a mask blank corresponding to the manufacturing method of the imprint mold by contacting a non-excited substance containing the compound of the present invention. Since high etching selectivity is obtained between and, the damage of the board | substrate after thin film removal can be reduced.

Thus, also in this embodiment, since the damage of the surface of a board | substrate by removing a thin film is small, since the process load of repolishing is also small, the regeneration cost of a board | substrate can be reduced and a high quality board | substrate can be reproduced further.

Moreover, the manufacturing method of the mask blank corresponding to the manufacturing method of the imprint mold which uses the board | substrate recycled by this regeneration method can also be provided. That is, the mask blank using a high quality regeneration board | substrate is manufactured by low cost by forming a thin film for pattern formation again on the board | substrate recycled by this regeneration method, for example using DC magnetron sputtering method. can do.

[Example]

Hereinafter, embodiment of this invention is described further more concretely by an Example. In addition, the comparative example with respect to an Example is also demonstrated.

(Example 1)

On a light-transmissive substrate made of synthetic quartz glass, a mixed target (atomic% ratio Mo: Si = 12: 88) of molybdenum (Mo) and silicon (Si) was used as a sputtering target using a single-sheet sputtering apparatus. In a mixed gas atmosphere of argon (Ar), nitrogen (N ₂ ), and helium (He) (gas pressure 0.3 kPa, gas flow rate ratio Ar: N ₂ : He = 8: 72: 100), the power of the DC power supply is 3.0 kW. Then, by reactive sputtering (DC sputtering), a phase shift film for an ArF excimer laser (wavelength 193 nm) composed of a single layer composed of molybdenum, silicon, and nitrogen having a thickness of 70 nm as a main component is formed to form a phase shift mask blank. Was produced. In addition, the phase shift film had a transmittance of 4.52% and a phase difference of 182.5 degrees with an ArF excimer laser (wavelength of 193 nm).

Next, assuming that surface defects not allowed in the phase shift mask blank produced as described above exist, the phase shift film of this phase shift mask blank was removed and the substrate was regenerated.

That is, by providing the phase shift mask blank in the chamber, introducing a mixed gas of ClF ₃ and Ar (flow ratio ClF ₃ : Ar = 0.2: 1.8 (SLM)) into the chamber to replace the chamber with the gas. The phase shift film of the said phase shift mask blank was made to contact the said mixed gas of a non-excited state. The gas pressure at this time was 488-502 Torr, the temperature was adjusted to 195-202 degreeC, and processing time was 10 minutes.

Thus, when the surface of the board | substrate from which the phase shift film which consists of MoSiN was removed was observed with the electron microscope, generation | occurrence | production of the residue of a phase shift film and altered layers, such as cloudiness, was not confirmed. Moreover, although the surface reflectance (200-700 nm) of the board | substrate after phase shift film removal was measured, there was no change with the board | substrate before film-forming. Moreover, as a result of measuring the surface roughness of the board | substrate which removed the phase shift film by atomic force microscope (AFM), it is Ra = 0.32 nm and Rmax = 6.27 nm, and the surface roughness (Ra = 0.11 nm, Rmax) of the board | substrate before peeling of a phase shift film. = 1.26 nm), the surface was slightly roughened, but surface roughness could be easily recovered by refining the substrate surface (the final step in the normal polishing process).

That is, according to this regeneration method, it was confirmed that there was little damage of the board | substrate after thin film removal.

Further, by forming the phase shift film on the substrate regenerated as described above, a phase shift mask blank using a high quality regenerated substrate can be produced.

(Example 2)

On a light-transmissive substrate made of synthetic quartz glass, a mixed target (atomic% ratio Mo: Si = 21: 79) of molybdenum (Mo) and silicon (Si) was used as a sputtering target using a single-sheet sputtering apparatus. In a mixed gas atmosphere of argon (Ar) and nitrogen (N ₂ ) (gas pressure 0.07 kPa, gas flow rate ratio Ar: N ₂ = 25: 28), the power of the DC power supply was 2.1 kW, and by reactive sputtering (DC sputtering) And a MoSiN film (light shielding layer) was formed to have a film thickness of 50 nm, followed by argon (Ar) and oxygen (O ₂ ), using a Mo / Si target (atomic% ratio Mo: Si = 4: 96). In a mixed gas atmosphere of nitrogen (N ₂ ) and helium (He) (gas pressure 0.1 kPa, gas flow rate ratio Ar: O ₂ / N ₂ / He = 6: 3: 11: 17), the power of the DC power supply is 3.0 kPa Then, by forming a MoSiON film (surface antireflection layer) at a film thickness of 10 nm, a light shielding film for an ArF excimer laser (wavelength 193 nm) consisting of a stack of a MoSiN film and a MoSiON film is formed, and a binary mask blank The croque was produced. In addition, the optical density of the light shielding film with respect to ArF excimer laser was 3.0.

Next, assuming that surface defects not allowed in the binary mask blank produced as described above exist, the light shielding film of the binary mask blank was removed to regenerate the substrate.

That is, by installing the binary mask blank in the chamber, introducing a mixed gas of ClF ₃ and Ar (flow ratio ClF ₃ : Ar = 0.2: 1.8 (SLM)) into the chamber to replace the chamber with the gas. The light shielding film of the binary mask blank was brought into contact with the mixed gas in an unexcited state. The gas pressure at this time was adjusted to 495-502 Torr, the temperature was 195-201 degreeC, and the processing time was 10 minutes.

Thus, when the surface of the board | substrate which removed the light shielding film which consists of lamination | stacking of a MoSiN film and a MoSiON film was observed with the electron microscope, generation | occurrence | production of deterioration layers, such as the residue of a light shielding film and turbidity, was not confirmed. Moreover, although the surface reflectance (200-700 nm) of the board | substrate after light shielding film removal was measured, there was no change with the board | substrate before film-forming. The surface roughness of the substrate from which the light shielding film was removed was measured by atomic force microscope (AFM), and as a result, Ra = 0.22 nm and Rmax = 3.06 nm, and the surface roughness of the substrate before peeling off the light shielding film (Ra = 0.11 nm, Rmax = 1.26). Although it was slightly rough compared to (nm), the surface roughness could be easily recovered by refining polishing of the substrate surface (the final step in the normal polishing process).

That is, according to this regeneration method, it was confirmed that there was little damage of the board | substrate after thin film removal.

In addition, by forming the light shielding film on the regenerated substrate as described above, a binary mask blank using a high-quality regenerated substrate can be produced.

(Example 3)

On a translucent substrate made of synthetic quartz glass, a tantalum (Ta) target is used as a sputter target using a single-sheet sputtering apparatus, and a mixed gas atmosphere (gas pressure 0.076 kPa, gas pressure of xenon (Xe) and nitrogen (N ₂ )) At a flow rate ratio Xe: N ₂ = 71: 29), the power of the DC power supply is set to 1.5 mA, and a TaN film is formed to have a thickness of 42 nm by reactive sputtering (DC sputtering), and then a Ta target is used. In a mixed gas atmosphere of argon (Ar) and oxygen (O ₂ ) (gas pressure of 0.3 kPa, gas flow rate ratio Ar: O ₂ = 58: 32.5), the power of the DC power supply was 2.0 kPa, and the TaO film was formed with a film thickness of 9 nm. By forming the light shielding film for ArF excimer laser (wavelength 193 nm) which consists of lamination | stacking of a TaN film and a TaO film, the binary mask blank was produced. In addition, the optical density of the light shielding film with respect to ArF excimer laser was 3.1.

Next, assuming that surface defects not allowed in the binary mask blank produced as described above exist, the light shielding film of the binary mask blank was removed to regenerate the substrate.

That is, by installing the binary mask blank in the chamber, introducing a mixed gas of ClF ₃ and Ar (flow ratio ClF ₃ : Ar = 0.2: 1.8 (SLM)) into the chamber to replace the chamber with the gas. The light shielding film of the binary mask blank was brought into contact with the mixed gas in an unexcited state. The gas pressure at this time was adjusted to 496-504 Torr, the temperature was 198-202 degreeC, and the processing time was 10 minutes.

Thus, when the surface of the board | substrate which removed the light shielding film which consists of lamination | stacking of a TaN film and a TaO film was observed with the electron microscope, generation | occurrence | production of the deterioration layer, such as the residue of a light shielding film, and turbidity, was not confirmed. Moreover, although the surface reflectance (200-700 nm) of the board | substrate after light shielding film removal was measured, there was no change with the board | substrate before film-forming. Moreover, as a result of measuring the surface roughness of the board | substrate from which the light shielding film was removed, it was Ra = 1.57 nm and Rmax = 21.4 nm, and the surface roughness (Ra = 0.11 nm, Rmax = 1.26) before peeling of a light shielding film. Although it was rough compared with (nm), surface roughness could be easily recovered by refining polishing of the board | substrate surface (final stage in a normal grinding | polishing process).

That is, according to this regeneration method, it was confirmed that there was little damage of the board | substrate after thin film removal.

In addition, by forming the light shielding film on the regenerated substrate as described above, a binary mask blank using a high-quality regenerated substrate can be produced.

(Example 4)

Mo / suitable for an EUV light wavelength region of 13 to 14 nm on a substrate (smooth 0.15 nm Rq or less, flatness 50 nm or less) made of SiO ₂ -TiO ₂ -based glass (coefficient of thermal expansion 0.2 × 10 ⁻⁷ / ° C.). An Si periodic multilayer reflective film was formed. That is, the multilayer reflective film was formed by alternately laminating the substrate on the substrate by ion beam sputtering, using a Mo target and a Si target. First, 4.2 nm of Si films and 2.8 nm of Mo films were formed, and 40 cycles of lamination were made using this as one cycle, followed by 4.2 nm of Si films. Finally, a 2.5 nm film of RuNb was formed using a RuNb target as a protective film.

Thus, the board | substrate which has a multilayer reflective film was produced. It was 65.9% when the reflectance of this 13.5 nm EUV light was measured at the incident angle of 6.0 degrees with respect to this multilayer reflective film.

Next, assuming that a surface defect that is not allowed exists in the substrate having the multilayer reflective film produced as described above, the multilayer reflective film of the substrate having the multilayer reflective film was removed to regenerate the substrate.

That is, a substrate having the multilayer reflective film is provided in the chamber, and a mixed gas of ClF ₃ and Ar (flow ratio ClF ₃ : Ar = 0.2: 1.8 (SLM)) is introduced into the chamber to replace the chamber with the gas. The multilayer reflective film of the substrate having the multilayer reflective film was brought into contact with the mixed gas in an unexcited state. The gas pressure at this time was adjusted to 495-502 Torr, the temperature was 195-201 degreeC, and the processing time was 10 minutes.

Thus, when the surface of the board | substrate which removed the EUV multilayer reflective film which consists of alternating laminated films of Mo film | membrane and Si film | membrane was observed with the electron microscope, generation | occurrence | production of the deterioration layer, such as the residue of a multilayer reflective film, and turbidity, was not confirmed. Moreover, although the surface reflectance (200-700 nm) of the board | substrate after multilayer reflective film removal was measured, there was no change with the board | substrate before film-forming. The surface roughness of the substrate from which the multilayer reflective film was removed was measured by atomic force microscope (AFM). As a result, Ra = 1.09 nm and Rmax = 13.8 nm, and the surface roughness of the substrate before peeling off the multilayer reflective film (Ra = 0.11 nm, Rmax). = 1.26 nm), the surface roughness was easily recovered by refining the substrate surface (the final step in the normal polishing process).

That is, according to this regeneration method, it was confirmed that the damage of the board | substrate after removing the multilayer reflective film of the board | substrate which has a multilayer reflective film is small.

Further, by forming the multilayer reflective film on the substrate regenerated as described above, it is possible to manufacture a substrate having a multilayer reflective film using a high quality regenerated substrate.

(Example 5)

Initially, the board | substrate which has a multilayer reflective film was produced by the procedure similar to Example 4.

Next, xenon (Xe) is used on a RuNb protective film by using a single-layered sputtering device, using a mixed target of tantalum (Ta) and boron (B) (atomic% ratio Ta: B = 80: 20) as a sputtering target. ) And a nitrogen gas (N ₂ ) in a mixed gas atmosphere (gas flow rate ratio Xe: N ₂ = 13: 6), the power of the DC power supply is 1.5 kW, and the TaBN film is 50 nm thick by reactive sputtering (DC sputtering). Film formation, and then, using the same TaB mixed target, the power of the DC power supply was 0.7 kW in a mixed gas atmosphere of argon (Ar) and oxygen (O ₂ ) (gas flow rate ratio Ar: O ₂ = 58: 32.5). By forming a TaBO film with a film thickness of 15 nm, an absorber film composed of a TaBN film and a TaBO film was formed, and a reflective mask blank to which EUV exposure light was applied was produced.

Next, assuming that there are surface defects that are not allowed in the reflective mask blank produced as described above, all of the thin film and the multilayer reflective film such as the absorber film of the reflective mask blank are removed and the substrate is regenerated. It was.

That is, by installing the reflective mask blank in the chamber, introducing a mixed gas of ClF ₃ and Ar (flow ratio ClF ₃ : Ar = 0.2: 1.8 (SLM)) into the chamber to replace the chamber with the gas. The mixed gas in an unexcited state was brought into contact with the surface of the absorber film of the reflective mask blank. The gas pressure at this time was adjusted to 495-502 Torr, the temperature was 195-201 degreeC, and the processing time was 10 minutes.

Thus, the surface of the board | substrate which removed all the EUV multilayer reflecting films which consist of a laminated structure of TaBN and TaBO, a RuNb protective film, and an alternating laminated film of Mo film | membrane and Si film | membrane was observed with the electron microscope, and the residue of a multilayer reflective film, etc. Occurrence of altered layers, such as haze, was not confirmed. Moreover, although the surface reflectance (200-700 nm) of the board | substrate after removal was measured, there was no change with the board | substrate before film-forming. Moreover, as a result of measuring the surface roughness of the removed substrate by atomic force microscope (AFM), it was Ra = 1.12 nm and Rmax = 14.3 nm, and compared with the surface roughness (Ra = 0.11 nm, Rmax = 1.26 nm) of the board | substrate before peeling. Although the surface was roughened, surface roughness could be easily recovered by refining the substrate surface (the final step in the normal polishing process).

That is, according to this regeneration method, it was confirmed that the damage of the board | substrate after removing all the absorber film | membrane of a reflective mask blank, a protective film, and a multilayer reflective film was few.

Further, by forming the multilayer reflective film, the protective film, and the absorber film on the regenerated substrate as described above, a reflective mask blank to which EUV exposure light using a high quality regenerated substrate is applied can be manufactured.

(Example 6)

On the light-transmissive substrate made of synthetic quartz glass, argon was used as a sputtering target using an alloy target of tantalum (Ta) and hafnium (Hf) (atomic% ratio Ta: Hf = 80:20) as a sputtering target. In a gas atmosphere (gas pressure of 0.3 kPa), the power of the DC power supply is 2.0 kW, the TaHf film (conductive film) is formed to a film thickness of 7 nm by reactive sputtering (DC sputtering), and then a chromium target is used. Then, in a mixed gas atmosphere of argon (Ar) and nitrogen (N ₂ ), a CrN film (Cr: N = 80: 20 atomic% ratio) is formed to a film thickness of 2.5 nm to form a laminated thin film of a TaHf film and a CrN film. The mask blanks used for preparation of the imprint mold were produced.

Next, assuming that surface defects that are not allowed in the mask blank produced as described above exist, the laminated thin film of the mask blank was removed to regenerate the substrate.

That is, initially, a mixed liquid of dicerium ammonium nitrate, perchloric acid and pure water was sprayed onto the surface of the CrN film with a nozzle to remove the CrN film.

Next, a mask blank from which the CrN film is removed is provided in the chamber, and a mixed gas of ClF ₃ and Ar (flow ratio ClF ₃ : Ar = 0.2: 1.8 (SLM)) is introduced into the chamber to replace the chamber with the gas. Thus, the TaHf film of the mask blank was brought into contact with the mixed gas in an unexcited state. The gas pressure at this time was adjusted to 495-502 Torr, the temperature was 195-201 degreeC, and the processing time was 10 minutes.

Thus, when the surface of the board | substrate which removed the laminated thin film of a TaHf film and a CrN film was observed with the electron microscope, generation | occurrence | production of the deterioration layer, such as the residue of a laminated thin film and turbidity, was not confirmed. Moreover, although the surface reflectance (200-700 nm) of the board | substrate after laminated thin film removal was measured, there was no change with the board | substrate of the initial stage before film-forming. Moreover, as a result of measuring the surface roughness of the board | substrate after removing a laminated thin film by atomic force microscope (AFM), it is Ra = 1.40nm and Rmax = 18.0nm, The surface roughness of the board | substrate before peeling of a laminated thin film (Ra = 0.11nm, Although it was rough compared with Rmax = 1.26 nm), surface roughness could be easily recovered by refining polishing of the substrate surface (the final step in a normal polishing process).

That is, according to this regeneration method, it was confirmed that the damage of the board | substrate after removing the laminated thin film of the said mask blank was small.

In addition, by forming a laminated thin film of the TaHf film and the CrN film on the regenerated substrate as described above, a mask blank for forming an imprint mold using a high-quality regenerated substrate can be produced.

(Comparative Example 1)

The substrate was regenerated by removing the phase shift film of the phase shift mask blank produced in Example 1 by a conventional method.

That is, the said phase shift mask blank was immersed in the hydrofluoric acid solution (concentration 0.2%) accommodated in the processing tank. The temperature of the hydrofluoric acid solution at this time was 40 degreeC, and processing time was 30 minutes. In addition, it performed, stirring the mask blank suitably during the process.

Thus, when the surface of the board | substrate from which the phase shift film which consists of MoSiN was removed was observed with the electron microscope, the residue of the phase shift film was not observed especially, but it turned out that the deterioration layer by cloudiness etc. formed on the surface of the board | substrate. Moreover, although the surface reflectance (200-700 nm) of the board | substrate after phase shift film removal was measured, the reflectance fell as a whole compared with the board | substrate before film-forming due to the influence which this deteriorated layer produced | generated. Moreover, as a result of measuring the surface roughness of the board | substrate after removing a phase shift film by atomic force microscope (AFM), it is Ra = 15.1 nm and Rmax = 150 nm, and the surface roughness of the board | substrate before peeling of a phase shift film (Ra = 0.11 nm, Compared with Rmax = 1.26 nm), it was confirmed that the roughness was very large and the substrate damage by film removal was large. Therefore, in order to restore favorable surface roughness by repolishing the substrate surface, it is necessary to perform repolishing from the first stage in the substrate polishing process before normal film formation, and the process load of repolishing becomes large.

Claims (17)

A method of regenerating a substrate by removing a mask blank including a thin film for pattern formation on a main surface of a substrate made of glass or the thin film of a transfer mask manufactured by using the mask blank.
A non-excitation including the compound of any one of chlorine (Cl), bromine (Br), iodine (I), and xenon (Xe) and fluorine (F) as the thin film of the mask blank or the transfer mask A method for regenerating a substrate, wherein the substrate is contacted and removed. The method of claim 1,
The said thin film consists of a single | mono layer or multiple layers, and the layer which contact | connects the said board | substrate at least is formed from the material which can be dry-etched with a fluorine-type gas. The method of claim 2,
The layer in contact with the substrate is formed of any one of a material containing silicon (Si), a material containing metal and silicon (Si), and a material containing tantalum (Ta). How to play. The method of claim 1,
And the substrate is made of synthetic quartz glass. The thin film for pattern formation is formed on the board | substrate regenerated by the regeneration method of the board | substrate of Claim 1, The manufacturing method of the mask blank characterized by the above-mentioned. A method of regenerating a substrate by removing the multilayer reflective film of a substrate with a multilayer reflective film having a multilayer reflective film having a structure in which a low refractive index layer and a high refractive index layer are alternately laminated on a main surface of a glass substrate.
The multilayer reflective film of the substrate with the multilayer reflective film is a non-excited state containing a compound of any one of chlorine (Cl), bromine (Br), iodine (I), and xenon (Xe) and fluorine (F). A method of regenerating a substrate, characterized in that the material is contacted and removed. The method of claim 6,
The low refractive index layer is made of silicon (Si) and is formed in contact with the main surface of the substrate. The method of claim 6,
The substrate is a regeneration method of the substrate, characterized in that made of SiO ₂ -TiO ₂ based low thermal expansion glass. A multilayer reflective film having a structure in which a low refractive index layer and a high refractive index layer are laminated alternately is formed on a substrate regenerated by the regeneration method of the substrate according to claim 6, wherein the substrate has a multilayer reflective film. On the main surface of the glass substrate, a reflective mask blank or a reflective mask blank including a multilayer reflective film having a structure in which a low refractive index layer and a high refractive index layer are alternately stacked, and an absorber film for pattern formation is used in order. A method of regenerating a substrate by removing the multilayer reflective film of a reflective mask fabricated by
The reflective mask blank or the multilayer reflective film of the reflective mask includes an element of any one of chlorine (Cl), bromine (Br), iodine (I), and xenon (Xe) and fluorine (F). A method for regenerating a substrate, characterized in that the material is brought into contact with and removed from an unexcited state. The method of claim 10,
The low refractive index layer is made of silicon (Si) and is formed in contact with the main surface of the substrate. The method of claim 10,
The substrate is a regeneration method of the substrate, characterized in that made of SiO ₂ -TiO ₂ based low thermal expansion glass. A multilayer reflective film having a structure in which a low refractive index layer and a high refractive index layer are alternately laminated on a substrate regenerated by the regeneration method according to claim 10, and an absorber film for pattern formation are sequentially formed. Method for producing a type mask blank. In the mask blank which comprises the thin film for pattern formation on the main surface of the board | substrate which consists of glass, the said thin film of the mask blank corresponding to the manufacturing method of the imprint mold which etching-processes the said thin film and the said board | substrate by dry etching process is carried out. As a method of removing and regenerating a substrate,
The thin film of the mask blank is brought into contact with an unexcited substance including a compound of any one of chlorine (Cl), bromine (Br), iodine (I), and xenon (Xe) with fluorine (F) And removing the substrate. The method of claim 14,
The said thin film consists of a single | mono layer or multiple layers, and the layer which contact | connects the said board | substrate at least is formed by the material which has a tantalum (Ta) as a main component. The method of claim 14,
And the substrate is made of synthetic quartz glass. The thin film for pattern formation is formed on the board | substrate regenerated by the regeneration method of the board | substrate of Claim 14, The manufacturing method of the mask blank characterized by the above-mentioned.

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