JP6302520B2 - Mask blank, phase shift mask manufacturing method, and semiconductor device manufacturing method - Google Patents

Description

  The present invention relates to a mask blank, a phase shift mask manufactured using the mask blank, and a manufacturing method thereof.

  Generally, in a semiconductor device manufacturing process, a fine pattern is formed using a photolithography method. Further, a number of substrates called transfer masks are usually used for forming this fine pattern. In order to miniaturize the pattern of a semiconductor device, it is necessary to shorten the wavelength of an exposure light source used in photolithography in addition to miniaturization of a mask pattern formed on a transfer mask. In recent years, as an exposure light source for manufacturing semiconductor devices, the wavelength has been shortened from an KrF excimer laser (wavelength 248 nm) to an ArF excimer laser (wavelength 193 nm).

  As a type 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 translucent substrate. A molybdenum silicide (MoSi) -based material is widely used for the phase shift film of the halftone phase shift mask. However, as disclosed in Patent Document 1, it has recently been found that MoSi-based films have low resistance to ArF excimer laser exposure light (so-called ArF light resistance). In Patent Document 1, plasma treatment, UV irradiation treatment, or heat treatment is performed on the MoSi-based film after the pattern is formed, and a passive film is formed on the surface of the MoSi-based film pattern. Sexuality is enhanced.

  Patent Document 2 discloses a photomask blank having a transition metal silicon-based material film made of a material containing a transition metal, silicon, oxygen, and nitrogen on a transparent substrate. Also in this patent document 2, when the exposure light (ArF exposure light) of ArF excimer laser is irradiated for a long time to the transition metal silicon-based material film on which the pattern is formed, the phenomenon that the line width of the pattern changes occurs. Doing this is a technical challenge. On the other hand, Patent Document 3 discloses a phase shift mask including a phase shift film made of SiNx.

JP 2010-217514 A JP 2012-58593 A Japanese Patent Laid-Open No. 8-220731

  The method for improving ArF light resistance for forming a passive film on the surface of a pattern formed of a MoSi-based film in Patent Document 1 does not change even the internal structure of the MoSi-based film. That is, it can be said that the ArF light resistance is equivalent to the conventional one in the MoSi-based film. For this reason, it is necessary to form a passivation film not only on the upper surface layer of the MoSi-based film pattern but also on the surface layer of the side wall. In Patent Document 1, after a pattern is formed on a MoSi-based film, a passive film is formed by performing plasma treatment, UV irradiation treatment, or heat treatment. However, the pattern formed on the MoSi-based film has a large in-plane density difference, and the distance between the side walls of adjacent patterns is often greatly different. Therefore, there is a problem that it is not easy to form a passive film having the same thickness on the sidewalls of all patterns.

  In the transition metal silicon-based material film in Patent Document 2, the oxygen content in the film is set to 3 atomic% or more, and the silicon content and the transition metal content are within a range satisfying a predetermined relational expression. It is said that ArF light resistance can be improved by providing a surface oxide layer on the surface of the silicon-based material film. It can be expected that the ArF light resistance is improved as compared with the conventional transition metal silicon-based material film. The hypothesis that the change (thickening) of the line width in the pattern made of a transition metal silicon-based material film due to ArF excimer laser irradiation is caused by the transition metal in the film being destabilized by photoexcitation by ArF excimer laser irradiation Influential. For this reason, even if it was the transition metal silicon-type material film of patent document 2, since the transition metal was contained, there existed a problem that it was difficult to fully solve the problem of ArF light resistance.

  Moreover, it is essential for the transition metal silicon-based material film in Patent Document 2 to contain oxygen. The increase in transmittance with respect to ArF exposure light due to the inclusion of oxygen in the film is significantly greater than that of nitrogen. For this reason, there is a problem that the thickness of the film is inevitably increased as compared with a transition metal silicon-based material film (for example, MoSiN) that does not contain oxygen.

  On the other hand, although it is a film made of SiNx that does not contain a transition metal as described in Patent Document 3, when ArF excimer laser is irradiated for a long time on a pattern formed on this SiNx film The change of the pattern width (thickness) was very small compared to the transition metal silicon-based material film, and it was confirmed by the present inventors that the film has high ArF light resistance. However, it is not easy to apply this SiNx film to a halftone phase shift film suitable for ArF exposure light.

  The halftone phase shift film (hereinafter, simply referred to as “phase shift film”) transmits ArF exposure light at a predetermined transmittance and the thickness of the phase shift film with respect to ArF exposure light transmitted through the phase shift film. And a function of causing a predetermined phase difference between the light and the light that has passed through the air by the same distance. When the phase shift film is formed as a single layer, it is necessary to use a material having a refractive index n with respect to ArF exposure light to a certain degree and a small extinction coefficient k to a certain degree. Silicon is a material that has a somewhat large extinction coefficient k for ArF exposure light, but has a tendency that the refractive index n is significantly small. Transition metals are materials that tend to have large extinction coefficient k and refractive index n for ArF exposure light. Further, when oxygen is contained in the film material, the extinction coefficient k with respect to ArF exposure light greatly decreases, and the refractive index n tends to decrease. When nitrogen is contained in the film material, the extinction coefficient k for ArF exposure light decreases, but the refractive index n tends to increase.

  Because of the optical characteristics of each element as described above, when the phase shift film is formed of a conventional transition metal silicon-based material, it contains a transition metal that is a material having a large refractive index n and extinction coefficient k. Even if oxygen is contained to some extent or nitrogen content is reduced to some extent, predetermined transmittance and phase difference can be ensured. In contrast, when the phase shift film is formed of a silicon-based material that does not contain a transition metal, since silicon is a material having a significantly low refractive index n, nitrogen, which is an element that raises the refractive index, is used as a conventional transition metal. It must be contained more than the silicon-based material. Further, since a large amount of nitrogen tends to increase the transmittance of the phase shift film, the oxygen content in the phase shift film needs to be reduced as much as possible. As described above, when a phase shift film having a single layer structure is formed of a silicon-based material such as SiNx that does not contain a transition metal, there are more restrictions than before.

  Generally, not only the phase shift film but also a thin film for forming a mask blank pattern is formed by a sputtering method. When a thin film is formed on a light-transmitting substrate by a sputtering method, it is usually performed to select conditions that allow relatively stable film formation. For example, when a SiNx film is formed by a sputtering method, a Si target is disposed in the film forming chamber, and a rare gas converted into plasma collides with the Si target while constantly circulating a mixed gas of a rare gas such as Ar and nitrogen. This is performed by a process in which the Si particles jumped out take nitrogen in the middle and deposit on the light-transmitting substrate (such sputtering is generally referred to as “reactive sputtering”). The nitrogen content of the SiNx film is mainly adjusted by increasing or decreasing the mixing ratio of nitrogen in the mixed gas, which makes it possible to form SiNx films with various nitrogen contents on the light-transmitting substrate. It has become.

However, depending on the mixing ratio of nitrogen in the mixed gas, stable film formation may be possible and stable film formation may be difficult. For example, when a SiNx film is formed by reactive sputtering, a nitrogen gas mixture ratio in a mixed gas that forms a stoichiometrically stable Si ₃ N ₄ or a film with a nitrogen content close thereto ( Such a film forming condition region is referred to as “poison mode” or “reaction mode” (see FIG. 4), and the film can be formed relatively stably. In addition, in the case of a nitrogen gas mixture ratio in a mixed gas that forms a film having a low nitrogen content (the region of such film formation conditions is referred to as “metal mode”, see FIG. 4). It is possible to form a film stably. On the other hand, in the case of the nitrogen gas mixture ratio in the mixed gas between the poison mode and the metal mode (the region of such film formation conditions is referred to as “transition mode”, see FIG. 4), the film formation is unstable. The uniformity of the composition and optical characteristics in the surface of the SiNx film and in the film thickness direction is low, and defects in the formed film frequently occur. In addition, when a SiNx film is formed on each of a plurality of translucent substrates, there is a tendency that the uniformity of the composition and optical characteristics of the SiNx film between the substrates is lowered. When forming a phase shift film to which ArF exposure light is applied with a single layer structure of SiNx, it is often necessary to form the film by reactive sputtering in a transition mode region where the film formation tends to be unstable. It was.

  Therefore, the present invention has been made to solve the conventional problems, and in a mask blank provided with a phase shift film on a light-transmitting substrate, ArF light resistance is lowered in a material for forming the phase shift film. Even when a silicon-based material that does not contain a transition metal as a factor is applied, the composition and optical characteristics of the phase shift film in the plane and in the film thickness direction are high, and the composition of the phase shift film between multiple substrates An object of the present invention is to provide a mask blank having high uniformity of optical characteristics and low defects. Another object of the present invention is to provide a phase shift mask manufactured using this mask blank. Furthermore, this invention aims at providing the method of manufacturing such a mask blank and a phase shift mask.

In order to achieve the above object, the present invention has the following configuration.
According to Configuration 1 of the present invention, a phase shift film having a function of transmitting ArF exposure light at a predetermined transmittance and causing a predetermined amount of phase shift to the transmitted ArF exposure light on a translucent substrate. A mask blank provided,
The phase shift film includes a structure in which a low transmission layer and a high transmission layer are laminated,
The low-permeability layer and the high-permeability layer are formed of a material composed of silicon and nitrogen, or a material containing one or more elements selected from a metalloid element, a non-metal element, and a rare gas in the material,
The low transmission layer is a mask blank characterized in that the nitrogen content is relatively smaller than that of the high transmission layer.

  Configuration 2 of the present invention is as follows. That is, the mask blank according to Configuration 1, wherein the low transmission layer and the high transmission layer are made of the same constituent element.

  Configuration 3 of the present invention is as follows. That is, the phase shift film has two or more sets of a laminated structure including one layer of the low transmission layer and one layer of the high transmission layer, and the mask blank according to Configuration 1 or 2 It is.

  Configuration 4 of the present invention is as follows. That is, the mask blank according to any one of Structures 1 to 3, wherein the low transmission layer and the high transmission layer are formed of a material made of silicon and nitrogen.

Configuration 5 of the present invention is as follows. That is, the low transmission layer is formed of a material having a refractive index n with respect to ArF exposure light of less than 2.5 and an extinction coefficient k of 1.0 or more.
The high transmission layer is formed of a material having a refractive index n with respect to ArF exposure light of 2.5 or more and an extinction coefficient k of less than 1.0. It is a mask blank as described in above.

  Configuration 6 of the present invention is as follows. That is, in the mask blank according to any one of the structures 1 to 5, the thickness of any one of the low transmission layer and the high transmission layer is 20 nm or less.

  Configuration 7 of the present invention is as follows. That is, the phase shift film is formed of a material consisting of silicon, nitrogen and oxygen at a position farthest from the translucent substrate, or one or more elements selected from a semi-metal element, a non-metal element, and a rare gas. The mask blank according to any one of Structures 1 to 6, further comprising an uppermost layer formed of a material containing

  Configuration 8 of the present invention is as follows. That is, the uppermost layer is a mask blank according to Configuration 7, wherein the uppermost layer is made of a material made of silicon, nitrogen, and oxygen.

  A ninth aspect of the present invention is a phase shift mask in which a transfer pattern is formed on the phase shift film of the mask blank according to any one of the first to eighth aspects.

In the configuration 10 of the present invention, a phase shift film having a function of transmitting ArF exposure light at a predetermined transmittance and causing a predetermined amount of phase shift to the transmitted ArF exposure light on a translucent substrate. A mask blank manufacturing method provided,
The phase shift film includes a structure in which a low transmission layer and a high transmission layer are laminated,
The translucent light is transmitted by reactive sputtering in a sputtering gas containing a nitrogen-based gas and a rare gas using a silicon target or a target composed of a material containing one or more elements selected from metalloid and non-metal elements. A low transmission layer forming step of forming the low transmission layer on the conductive substrate;
A sputtering target containing a nitrogen-based gas and a noble gas using a silicon target or a target made of a material containing at least one element selected from a metalloid element and a non-metal element in silicon, wherein the low-permeability layer forming step And a high transmission layer forming step of forming the high transmission layer on the translucent substrate by reactive sputtering in a sputtering gas having a higher mixing ratio of nitrogen-based gas than the case. It is a manufacturing method.

Configuration 11 of the present invention is as follows. That is, the sputtering gas used in the low-permeability layer forming step is selected to have a nitrogen-based gas mixing ratio that is less than the range of the nitrogen-based gas mixing ratio that results in a transition mode in which the film formation tends to be unstable. ,
11. The mask according to claim 10, wherein the sputtering gas used in the highly transmissive layer forming step has a nitrogen-based gas mixing ratio that is greater than a range of the nitrogen-based gas mixing ratio that is the transition mode. It is a manufacturing method of a blank.

  Configuration 12 of the present invention is as follows. That is, the low-permeability layer forming step is to form the low-permeability layer by reactive sputtering in a sputtering gas composed of a nitrogen gas and a rare gas using a silicon target. The method of manufacturing a mask blank according to Configuration 10 or 11, wherein the highly transmissive layer is formed by reactive sputtering in a sputtering gas composed of a nitrogen gas and a rare gas using a silicon target. .

Configuration 13 of the present invention is as follows. That is, the low transmission layer is formed of a material having a refractive index n with respect to ArF exposure light of less than 2.5 and an extinction coefficient k of 1.0 or more.
The high transmittance layer is formed of a material having a refractive index n with respect to ArF exposure light of 2.5 or more and an extinction coefficient k of less than 1.0. It is a manufacturing method of the mask blank of description.

  Configuration 14 of the present invention uses a silicon target or a target made of a material containing at least one element selected from a metalloid element and a nonmetal element in silicon, and the phase is obtained by sputtering in a sputtering gas containing a rare gas. 14. The mask blank manufacturing method according to any one of configurations 10 to 13, further comprising an uppermost layer forming step of forming an uppermost layer at a position farthest from the translucent substrate of the shift film.

  In the configuration 15 of the present invention, a silicon target is used, and the uppermost layer is formed at a position farthest from the translucent substrate of the phase shift film by reactive sputtering in a sputtering gas composed of a nitrogen gas and a rare gas. The method for producing a mask blank according to Configuration 12, further comprising a top layer forming step of performing a process of oxidizing at least a surface layer of the top layer.

  A configuration 16 of the present invention includes a step of forming a transfer pattern on the phase shift film of the mask blank manufactured by the mask blank manufacturing method according to any one of the configurations 10 to 15. It is a manufacturing method.

  In the mask blank of the present invention, a phase shift film having a function of transmitting ArF exposure light at a predetermined transmittance and causing a predetermined amount of phase shift to the transmitted ArF exposure light on a translucent substrate. The phase shift film includes a structure in which a low transmission layer and a high transmission layer are stacked, and the low transmission layer and the high transmission layer are made of a material composed of silicon and nitrogen, or a semimetal in the material. The low-permeability layer is formed of a material containing one or more elements selected from an element, a non-metallic element, and a rare gas, and has a feature that the nitrogen content is relatively smaller than that of the high-permeability layer. By using a mask blank having such a structure, a low-permeability layer made of a material having a low nitrogen content can be formed by reactive sputtering, using a mixed gas having a low mixing ratio of nitrogen gas as a sputtering gas, and forming a stable film. Stable film formation is possible by depositing a high transmission layer made of a material having a high nitrogen content using reactive gas and a mixed gas having a high nitrogen gas mixing ratio in the sputtering gas. It is possible to form a film under the film forming conditions. This makes it possible to increase the uniformity of the composition and optical characteristics in the plane and in the film thickness direction of the phase shift film, and to increase the uniformity of the composition and optical characteristics of the phase shift film between a plurality of substrates. Furthermore, a mask blank having a lower defect can be realized.

  In addition, the mask blank manufacturing method of the present invention has a function of transmitting ArF exposure light at a predetermined transmittance on a translucent substrate and causing a predetermined amount of phase shift to the transmitted ArF exposure light. A method of manufacturing a mask blank provided with a phase shift film having a structure in which a low transmission layer and a high transmission layer are laminated, and selected from a semi-metal element and a non-metal element on a silicon target or silicon. A low transmission layer forming step of forming a low transmission layer on a translucent substrate by reactive sputtering in a sputtering gas containing a nitrogen-based gas and a rare gas, using a target made of a material containing one or more elements And a nitrogen-based gas using a silicon target or a target made of a material containing one or more elements selected from metalloid and nonmetal elements in silicon A sputtering gas containing a noble gas, which has a high permeability layer formed on a translucent substrate by reactive sputtering in a sputtering gas in which the mixing ratio of the nitrogen-based gas is higher than in the low permeability layer forming step. And a transmissive layer forming step. By adopting such a mask blank manufacturing method, a low-permeability layer made of a material having a low nitrogen content is formed by a reactive sputtering, using a mixed gas with a low mixing ratio of nitrogen-based gas as a sputtering gas, and a stable composition. Films are formed under conditions that allow film formation, and a highly permeable layer made of a material with a high nitrogen content is formed by reactive sputtering, using a mixed gas with a high mixing ratio of nitrogen-based gas as the sputtering gas, and stable film formation. Therefore, it is possible to form a film under the film forming conditions capable of. This makes it possible to increase the uniformity of the composition and optical characteristics in the plane and in the film thickness direction of the phase shift film, and to increase the uniformity of the composition and optical characteristics of the phase shift film between a plurality of substrates. Furthermore, a mask blank having a lower defect can be manufactured.

It is sectional drawing which shows the structure of the mask blank in one Embodiment of this invention. It is sectional drawing which shows the manufacturing process of the transfer mask in another embodiment of this invention. It is sectional drawing which shows the manufacturing process of the transfer mask in embodiment of this invention. It is a schematic diagram for demonstrating the film-forming mode in the case of forming a thin film by reactive sputtering.

Hereinafter, each embodiment of the present invention will be described.
In the case where the phase shift film is formed of a silicon-based material film that contains silicon and nitrogen and does not contain a transition metal, the inventors have high uniformity of composition and optical characteristics in the thickness direction of the film, and We conducted intensive research on the means to realize low defect films. In the current film formation technology, reactive sputtering is used to form a silicon-based material film containing silicon and nitrogen and containing no transition metal on a substrate so that the composition and optical properties are highly uniform. It is necessary to apply the film formation technique by. However, in general, in the formation of a thin film by reactive sputtering, there are not a few phenomena in which the film formation rate and voltage of the thin film vary depending on the mixing ratio of the reactive gas in the film formation chamber.

  FIG. 4 shows a reactive gas mixture ratio in a mixed gas composed of a rare gas and a reactive gas (or a flow rate of the reactive gas in the mixed gas) when a thin film is formed by reactive sputtering. FIG. 2 is a graph schematically showing a general tendency with respect to a change in film forming speed that occurs when the ratio is changed. In FIG. 4, when the mixing ratio of the reactive gas in the mixed gas is gradually increased (increase mode), the curve I of the change in the deposition rate and the mixing ratio of the reactive gas in the mixed gas are gradually decreased. A curve D of the change in the film forming speed in the case of being reduced (decrease mode) is shown. Generally, the region where the mixing ratio of the reactive gas in the mixed gas is low (the region of the metal mode M in FIG. 4) and the region where the mixing ratio of the reactive gas in the mixed gas is high (the reaction mode R in FIG. 4). In the region), the fluctuation range of the film forming rate accompanying the change of the reactive gas mixture ratio in the mixed gas is small in both the increase mode and the decrease mode. Further, the difference in film formation rate between the increasing mode and the decreasing mode in the mixing ratio of the reactive gas in the same mixed gas is also small. Therefore, a thin film can be stably formed in the metal mode M region and the reaction mode R region. That is, it can be said that the region of the metal mode M and the region of the reaction mode R are regions where the uniformity of the composition and optical characteristics is high and a low defect thin film can be formed.

On the other hand, in the transition mode T region sandwiched between the metal mode M region and the reaction mode R region in FIG. 4, the film formation rate accompanying the change in the reactive gas mixture ratio in the mixed gas in both the increase mode and the decrease mode. The fluctuation range is large. In addition, the difference in deposition rate between the increase mode and the decrease mode in the mixing ratio of the reactive gas in the same mixed gas is large. In the region of the transition mode T, the film formation speed fluctuates greatly due to a minute change in the reactive gas mixture ratio in the mixed gas in the film formation chamber, and the shift from the increase mode to the decrease mode is caused by the minute change in the mixture ratio. The film forming speed fluctuates due to. For this reason, a thin film is formed in the state where the film-forming speed is unstable. Variation in the deposition rate affects the amount of reactive gas components contained in the thin film. That is, it can be said that the region of the transition mode T is a region where the uniformity of the composition and optical characteristics is high and it is difficult to form a thin film with low defects.

  When a phase shift film having a single layer structure made of a silicon-based material film not containing a transition metal is formed by reactive sputtering, it is highly necessary to form the film in the region of the transition mode T due to the required optical characteristics. There is also a method of searching for a combination of reactive gases having a small difference in film formation rate between the increasing mode and the decreasing mode in the transition mode T in the mixing ratio of the reactive gases in the same mixed gas. However, even if such a combination of reactive gases is found, the problem that the fluctuation range of the film forming rate due to the change in the mixing ratio of the reactive gas in the mixed gas in the transition mode T is not solved.

  When a silicon-based material film containing silicon and nitrogen and not containing a transition metal is formed by reactive sputtering in the metal mode region, ensure the film thickness to obtain the phase difference required for the phase shift film. Then, since the extinction coefficient k of the formed film material is high, it becomes lower than the required transmittance for ArF exposure light. Such a film hardly causes a phase shift effect and is not suitable for a phase shift film. On the other hand, when a silicon-based material film containing silicon and nitrogen and not containing a transition metal is formed by reactive sputtering using a reaction mode region, the film thickness for obtaining a phase difference required as a phase shift film is set. If it is going to ensure, since the extinction coefficient k of this formed film material is low, it will become higher than the required transmittance for ArF exposure light. Although such a film can provide a phase shift effect, there is a possibility that the resist film on the semiconductor wafer may be exposed to transmitted light from a pattern portion other than the region where the phase shift effect occurs. Is not suitable.

  As a result of diligent research on means for solving many technical problems that occur in realizing a phase shift film suitable for ArF exposure light using a silicon-based material film containing silicon and nitrogen and not containing a transition metal, A phase shift film having a structure in which a low transmission layer that is a silicon-based material film formed by reactive sputtering in a region and a high transmission layer that is a silicon-based material film formed by reactive sputtering in a reaction mode region are stacked. This led to the conclusion that the above technical problem could be solved.

  That is, according to the present invention, a phase shift film having a function of transmitting ArF exposure light at a predetermined transmittance and causing a predetermined amount of phase shift to the transmitted ArF exposure light is provided on the translucent substrate. The phase shift film includes a structure in which a low transmission layer and a high transmission layer are laminated, and the low transmission layer and the high transmission layer are formed of silicon and nitrogen, or the material. It is formed of a material containing one or more elements selected from a metalloid element, a nonmetallic element, and a rare gas, and the low-permeability layer has a relatively low nitrogen content as compared with the high-permeability layer. This is a mask blank.

  In the present invention, a phase shift film having a function of transmitting ArF exposure light at a predetermined transmittance and causing a predetermined amount of phase shift to the transmitted ArF exposure light is provided on the translucent substrate. The method of manufacturing a mask blank, wherein the phase shift film includes a structure in which a low transmission layer and a high transmission layer are laminated, and is a silicon target or at least one element selected from a semi-metal element and a non-metal element on silicon A low-transmission layer forming step of forming the low-transmission layer on the translucent substrate by reactive sputtering in a sputtering gas containing a nitrogen-based gas and a rare gas, using a target made of a material containing Nb; Using a target or a target made of a material containing one or more elements selected from a metalloid element and a nonmetal element in silicon, and containing a nitrogen-based gas and a rare gas A high transmission layer that forms the high transmission layer on the translucent substrate by reactive sputtering in a sputtering gas that is a sputtering gas and has a higher mixing ratio of nitrogen-based gas than in the low transmission layer formation step. It has a layer formation process, It is a manufacturing method of the mask blank characterized by the above-mentioned.

  Further, in this mask blank manufacturing method, the sputtering gas used in the low transmission layer forming step is less nitrogen-based than the range of the mixing ratio of nitrogen-based gas that becomes a transition mode in which the film formation tends to become unstable. The gas mixing ratio is selected, and the sputtering gas used in the highly permeable layer forming step is preferably selected to have a nitrogen gas mixing ratio that is larger than the range of the nitrogen gas mixing ratio in the transition mode.

  In the mask blank and mask blank manufacturing method of the present invention, the phase shift film is not a single layer structure but a laminated structure of a low transmission layer and a high transmission layer. By adopting such a laminated structure, the low-permeability layer is formed by reactive sputtering using a metal mode region where a film with a low nitrogen content tends to be formed, and the high-permeability layer is formed with a nitrogen content. The film can be formed by reactive sputtering in a reaction mode region in which a large number of films tend to be formed. As a result, it is possible to form both the low transmissive layer and the high transmissive layer by reactive sputtering under film formation conditions in which the film formation rate and voltage fluctuation during film formation are small, resulting in uniform composition and optical characteristics. A phase shift film having high properties and low defects can be formed.

  The low-permeability layer and the high-permeability layer are formed of a material composed of silicon and nitrogen, or a material containing one or more elements selected from metalloid elements, non-metal elements, and rare gases in the material. The low transmissive layer and the high transmissive layer do not contain a transition metal that may cause a decrease in light resistance to ArF exposure light. In addition, it is desirable not to include a metal element other than a transition metal in the low transmission layer and the high transmission layer because it cannot be denied that the light resistance to ArF exposure light can be reduced. The low transmission layer and the high transmission layer may contain any metalloid element in addition to silicon. Among these metalloid elements, the inclusion of one or more elements selected from boron, germanium, antimony and tellurium is preferable because it can be expected to increase the conductivity of silicon used as a sputtering target.

The low transmission layer and the high transmission layer may contain any nonmetallic element in addition to nitrogen. Among these nonmetallic elements, it is preferable to contain one or more elements selected from carbon, fluorine and hydrogen. The low-permeability layer and the high-permeability layer preferably have an oxygen content of 10 atomic percent or less, more preferably 5 atomic percent or less, and do not actively contain oxygen (RBS, XPS, etc.). More preferably, the result of the compositional analysis is less than the detection lower limit value). When oxygen is contained in the silicon-based material film, the extinction coefficient k tends to be greatly reduced, and the thickness of the entire phase soft film is increased. It is common light-transmissive substrate is formed of a material mainly containing SiO ₂ such as synthetic quartz glass. When either the low transmission layer or the high transmission layer is formed in contact with the surface of the translucent substrate, if the silicon-based material film contains oxygen, the composition of the silicon-based material film containing oxygen and the composition of the glass In the dry etching performed when the pattern is formed on the phase shift film, the difference may be reduced, and there may be a problem that it is difficult to obtain etching selectivity between the silicon-based material film and the translucent substrate.

  In a target made of a material containing one or more elements selected from a metalloid element and a nonmetal element in silicon, it is preferable to include one or more elements selected from boron, germanium, antimony, and tellurium as the metalloid element. These metalloid elements can be expected to increase the conductivity of the target. Therefore, when forming a low transmission layer and a high transmission layer by a DC sputtering method, the target may contain these metalloid elements. desirable.

  The low transmission layer and the high transmission layer may contain a rare gas. A rare gas is an element that can increase the deposition rate and improve the productivity by being present in the deposition chamber when a thin film is formed by reactive sputtering. When the rare gas is turned into plasma and collides with the target, the target constituent element is ejected from the target, and a thin film is formed on the translucent substrate while taking in the reactive gas in the middle. The rare gas in the film formation chamber is slightly taken in until the target constituent element jumps out of the target and adheres to the translucent substrate. Preferred examples of the rare gas required for the reactive sputtering include argon, krypton, and xenon. Moreover, in order to relieve the stress of the thin film, helium and neon having a small atomic weight can be actively incorporated into the thin film.

In the low transmission layer forming step for forming the low transmission layer of the phase shift film and the high transmission layer forming step for forming the high transmission layer, the sputtering gas contains a nitrogen-based gas. As the nitrogen-based gas, any gas can be used as long as it contains nitrogen. As described above, since it is preferable to keep the oxygen content low in the low-permeability layer and the high-permeability layer, it is preferable to apply a nitrogen-based gas not containing oxygen, and to apply nitrogen gas (N ₂ gas). More preferred.

  In the present invention, a phase shift film having a function of transmitting ArF exposure light at a predetermined transmittance and causing a predetermined amount of phase shift to the transmitted ArF exposure light is provided on a light-transmitting substrate. A method for manufacturing a mask blank, wherein the phase shift film includes a structure in which a low transmission layer and a high transmission layer are laminated, and includes a silicon target or one or more elements selected from metalloid and nonmetal elements in silicon A low-transmission layer forming step of forming the low-transmission layer on the translucent substrate by reactive sputtering in a sputtering gas containing a nitrogen-based gas and a rare gas, and a silicon target or Using a target made of a material containing one or more elements selected from a metalloid element and a nonmetal element in silicon, a sputter containing nitrogen-based gas and rare gas is used. A highly permeable layer which is a ring gas and forms the highly permeable layer on the translucent substrate by reactive sputtering in a sputtering gas having a higher nitrogen-based gas mixing ratio than in the low permeable layer forming step. It has a formation process, It is a manufacturing method of a mask blank characterized by the above-mentioned.

  It is preferable that the low transmission layer and the high transmission layer in the phase shift film have a structure in which they are directly in contact with each other without interposing other films. Moreover, it is preferable that the mask blank of this invention is a film | membrane structure where the film | membrane consisting of the material containing a metal element does not contact | connect neither a low permeable layer and a high permeable layer. This is because when a heat treatment or irradiation with ArF exposure light is performed in a state where a film containing a metal element is in contact with a film containing silicon, the metal element tends to diffuse into the film containing silicon.

  The low transmission layer and the high transmission layer are preferably made of the same constituent elements. When either the low transmission layer or the high transmission layer contains different constituent elements, and these layers are in contact with each other and are subjected to heat treatment or ArF exposure light irradiation, the different constituent elements are There is a possibility that it may move to the layer not containing the constituent elements and diffuse. And there exists a possibility that the optical characteristic of a low permeable layer and a high transmissive layer may change a lot from the beginning of film-forming. In particular, when the different constituent element is a metalloid element, it is necessary to form the low transmissive layer and the high transmissive layer using different targets.

In the mask blank of the present invention, examples of the material for the translucent substrate include quartz glass, aluminosilicate glass, soda lime glass, low thermal expansion glass (SiO ₂ —TiO ₂ glass, etc.), etc., in addition to synthetic quartz glass. Synthetic quartz glass has a high transmittance with respect to ArF excimer laser light (wavelength 193 nm), and is particularly preferable as a material for forming a light-transmitting substrate of a mask blank.

The order of stacking the low transmission layer and the high transmission layer in the phase shift film from the translucent substrate side may be any order. In the case of a phase shift film structure in which a low-transmission layer and a high-transmission layer are laminated in this order in contact with a translucent substrate, the low-transmission layer is a silicon-containing film having a low nitrogen content, and a material mainly composed of SiO ₂ There is an effect that the etching selectivity can be more easily obtained with the light-transmitting substrate formed in (1). The etching gas used for dry etching when forming a pattern on a silicon-containing film is generally a fluorine-based gas. However, if the silicon-containing film has a low nitrogen content, a chlorine-based gas may be used as an etching gas. Is also applicable. By using a chlorine-based gas for dry etching of the low transmission layer, the etching selectivity with the light-transmitting substrate can be greatly increased.

On the other hand, in the case of a phase shift film structure in which a high transmission layer and a transmission layer are stacked in this order in contact with a light transmitting substrate, the high transmission layer is a silicon-containing film having a high nitrogen content. Therefore, when a highly transmissive layer is formed in contact with a light transmissive substrate formed of a material containing SiO ₂ as a main component, high adhesion is obtained between the surface of the light transmissive substrate and the high transmissive layer. It has the effect of being easy to be done

  The low transmission layer and the high transmission layer in the phase shift film preferably have a structure in which they are laminated in direct contact with each other without using other films. This is because the silicon-containing film is preferably not in contact with a film made of a material containing a metal element.

  It is preferable that the phase shift film has two or more pairs of a laminated structure including one low transmission layer and one high transmission layer. Moreover, it is preferable that the thickness of any one of the low-permeability layer and the high-permeability layer is 20 nm or less. Since the required optical properties are greatly different between the low transmission layer and the high transmission layer, the difference in the nitrogen content in the film between them is large. For this reason, an etching rate difference in dry etching with a fluorine-based gas is large between the low transmission layer and the high transmission layer. When the phase shift film has a two-layer structure including one low transmission layer and one high transmission layer, when the pattern is formed by dry etching with a fluorine-based gas, the pattern of the phase shift film after etching is changed. A step is likely to occur in the cross section. By making the phase shift film a structure having two or more pairs of laminated structures each composed of one low transmission layer and one high transmission layer, each layer (one layer) of the low transmission layer and the high transmission layer Since the thickness of the film becomes thinner than that in the case of the two-layer structure (one set of laminated structures), the step generated in the cross section of the pattern of the phase shift film after etching can be reduced. Moreover, the level | step difference which arises in the cross section of the pattern of the phase shift film after an etching can be suppressed more by restrict | limiting the thickness of each layer (1 layer) in a low permeable layer and a high permeable layer to 20 nm or less.

In recent years, a defect that uses electron beam irradiation to correct a black defect that occurred when a transfer mask (phase shift mask) was formed by forming a transfer pattern by dry etching on a thin film (phase shift film) of a mask blank This is often done by correction (EB defect correction). In this EB defect correction, a non-excited substance such as XeF ₂ is gasified and supplied to the black defect portion, and the black defect portion is irradiated with an electron beam, whereby the thin film in the black defect portion is volatile fluoride. This is a technology that removes them by changing them. Conventionally, since a fluorine-based gas such as XeF ₂ used for EB defect correction is supplied in an unexcited state, it has been considered that a portion of a thin film not irradiated with an electron beam is hardly affected. However, it has been found that when the mask blank thin film is formed of a silicon-based compound, if the oxygen or nitrogen content is low, the mask blank is etched by a non-excited fluorine-based gas such as XeF ₂ . .

Since the low transmission layer of the phase shift film in the present invention is a silicon-based material film that has a low nitrogen content and does not actively contain oxygen, a fluorine-based gas in a non-excited state such as XeF ₂ when this EB defect is corrected It tends to be easily etched. For this reason, it is desirable that the low-permeability layer be placed in a state where it is difficult for non-excited fluorine-based gas such as XeF ₂ to come into contact. On the other hand, the high permeability layer, since the nitrogen content is often a silicon-based material film, the influence of the fluorine-based gas of the non-excited state, such as XeF ₂ may receive less likely. As described above, the phase shift film has a structure having two or more combinations of the laminated structure of the low transmission layer and the high transmission layer, so that the low transmission layer is sandwiched between two high transmission layers. It can be placed between the translucent substrate and the highly transmissive layer. As a result, the non-excited fluorine-based gas such as XeF ₂ may initially contact and etch the low-permeability layer, but after that, it becomes difficult to contact the low-permeability layer (the low-permeability layer Since the surface of the side wall is more intricate than the surface of the side wall of the highly permeable layer, gas is less likely to enter. Therefore, with such a stacked structure, the low transmission layer can be prevented from being etched by a non-excited fluorine-based gas such as XeF ₂ . Further, by limiting the thickness of each layer in the low transmission layer and the high transmission layer to 20 nm or less, the low transmission layer can be further suppressed from being etched by a non-excited fluorine-based gas such as XeF _2. .

  The low transmission layer and the high transmission layer are preferably formed of a material composed of silicon and nitrogen. Further, in this mask blank manufacturing method, in the low transmission layer forming step, the silicon target is used to form the low transmission layer by reactive sputtering in a sputtering gas composed of nitrogen gas and rare gas. In the layer forming step, it is preferable to form a highly transmissive layer by reactive sputtering in a sputtering gas composed of a nitrogen gas and a rare gas using a silicon target.

  As described above, the inclusion of a transition metal in the low transmissive layer and the high transmissive layer can be a factor in reducing the light resistance to ArF exposure light. When a metal other than transition metal or a metalloid element other than silicon is contained in the low-permeability layer and the high-permeability layer, the contained metal or metalloid element moves between the low-permeability layer and the high-permeability layer. As a result, the optical characteristics may change. Even in the case of a nonmetallic element, if oxygen is contained in the low transmission layer and the high transmission layer, the transmittance with respect to ArF exposure light is greatly reduced. Considering these matters, it is more preferable that the low-permeability layer and the high-permeability layer are formed of a material composed of silicon and nitrogen. The rare gas is an element that is difficult to detect even if a composition analysis such as RBS or XPS is performed on the thin film. For this reason, it can be considered that the material containing silicon and nitrogen includes a material containing a rare gas.

  The low transmission layer has a refractive index n with respect to ArF exposure light of less than 2.5 (preferably 2.4 or less, more preferably 2.2 or less, further preferably 2.0 or less), and an extinction coefficient k. The high transmission layer is formed of a material having a refractive index n of 1.0 or more (preferably 1.1 or more, more preferably 1.4 or more, and still more preferably 1.6 or more). 5 or more (preferably 2.6 or more) and an extinction coefficient k of less than 1.0 (preferably 0.9 or less, more preferably 0.7 or less, and even more preferably 0.4 or less). Preferably it is formed. In order to satisfy a predetermined phase difference and a predetermined transmittance with respect to ArF exposure light, which is a characteristic required as a phase shift film, when a phase shift film is configured by a laminated structure of two or more layers, a low transmission layer and a high transmission layer This is because it cannot be realized unless the refractive index n and the extinction coefficient k are within the above ranges.

  The refractive index n and extinction coefficient k of a thin film are not determined only by the composition of the thin film. The film density and crystal state of the thin film are factors that influence the refractive index n and the extinction coefficient k. For this reason, various conditions when forming a thin film by reactive sputtering are adjusted, and the thin film is formed so as to have a desired refractive index n and extinction coefficient k. In order to make the low transmission layer and the high transmission layer within the ranges of the refractive index n and the extinction coefficient k, the ratio of the mixed gas of the rare gas and the reactive gas is adjusted when forming the film by reactive sputtering. Not just that. There are a variety of positional relationships such as the pressure in the film formation chamber during reactive sputtering, the power applied to the target, and the distance between the target and the translucent substrate. These film forming conditions are unique to the film forming apparatus, and are appropriately adjusted so that the formed thin film has a desired refractive index n and extinction coefficient k.

  The phase shift film is a material containing silicon, nitrogen, and oxygen at a position farthest from the light-transmitting substrate, or a material containing one or more elements selected from a semimetal element, a nonmetal element, and a rare gas in the material It is preferable to provide an uppermost layer formed of Further, in this mask blank manufacturing method, a silicon target or a target made of a material containing one or more elements selected from a semi-metal element and a non-metal element is used for sputtering by sputtering in a sputtering gas containing a rare gas. It is preferable to have an uppermost layer forming step of forming the uppermost layer at a position farthest from the translucent substrate of the phase shift film. Furthermore, in this mask blank manufacturing method, the uppermost layer is formed at a position farthest from the translucent substrate of the phase shift film by reactive sputtering in a sputtering gas composed of nitrogen gas and rare gas using a silicon target. It is more preferable to have an uppermost layer forming step for forming and oxidizing at least the surface layer of the uppermost layer.

  A silicon-based material film that does not actively contain oxygen and contains nitrogen has high light resistance to ArF exposure light, but has lower chemical resistance than a silicon-based material film that actively contains oxygen. Tend. In addition, a mask blank having a configuration in which a high-transmitting layer or a low-transmitting layer containing nitrogen is not actively contained and nitrogen is contained as the uppermost layer on the side opposite to the light-transmitting substrate side of the phase shift film. In this case, it is difficult to avoid oxidation of the surface layer of the phase shift film by performing mask cleaning on the phase shift mask manufactured from the mask blank or storing it in the air. When the surface layer of the phase shift film is oxidized, the optical characteristics at the time of film formation are greatly changed. In particular, in the case of a configuration in which a low transmission layer is provided as the uppermost layer of the phase shift film, the increase in transmittance due to oxidation of the low transmission layer becomes large. The phase shift film is formed on the laminated structure of the low transmission layer and the high transmission layer, and further includes at least one material selected from silicon, nitrogen, and oxygen, or a semi-metal element, a non-metal element, and a rare gas. By providing the uppermost layer formed of a material containing an element, surface oxidation of the low transmission layer and the high transmission layer can be suppressed.

The uppermost layer formed of a material composed of silicon, nitrogen, and oxygen, or a material containing one or more elements selected from a metalloid element, a nonmetallic element, and a rare gas in the material is substantially the same in the thickness direction of the layer. In addition to the composition, the composition is inclined in the thickness direction of the layer (the composition having a composition gradient in which the oxygen content in the layer increases as the uppermost layer moves away from the translucent substrate). . Examples of a material suitable for the uppermost layer having a structure having substantially the same composition in the layer thickness direction include SiO ₂ and SiON. As the uppermost layer having a composition gradient in the thickness direction of the layer, the translucent substrate side is SiN, the oxygen content increases as the distance from the translucent substrate increases, and the surface layer is composed of SiO ₂ or SiON It is preferable that

For the formation of the uppermost layer, a silicon target or a target made of a material containing at least one element selected from a metalloid element and a nonmetal element is used in a sputtering gas containing nitrogen gas, oxygen gas, and rare gas. An uppermost layer forming step formed by reactive sputtering at 1 can be applied. This uppermost layer forming step can be applied to the formation of the uppermost layer of the structure having substantially the same composition in the layer thickness direction and the uppermost layer having a composition-graded structure. In addition, for the formation of the uppermost layer, a silicon dioxide (SiO ₂ ) target or a target made of a material containing one or more elements selected from a metalloid element and a nonmetal element in silicon dioxide (SiO ₂ ) is used, and a rare gas is used. An uppermost layer forming step of forming by sputtering in a sputtering gas containing can be applied. This uppermost layer forming step can also be applied to the formation of either the uppermost layer having a composition having substantially the same composition in the layer thickness direction or the uppermost layer having a composition-graded structure.

  For the formation of the uppermost layer, a silicon target or a target made of a material containing at least one element selected from a metalloid element and a nonmetal element is used, and the reactivity in a sputtering gas containing a nitrogen gas and a rare gas is used. An uppermost layer forming step in which a process of oxidizing at least the surface layer of the uppermost layer is performed by sputtering can be applied. This uppermost layer forming step can basically be applied to the formation of the uppermost layer having a composition gradient in the thickness direction of the layer. Examples of the treatment for oxidizing the uppermost surface layer in this case include a heat treatment in an oxygen-containing gas such as the air, and a treatment in which ozone or oxygen plasma is brought into contact with the uppermost layer.

  The low transmission layer, the high transmission layer, and the uppermost layer in the phase shift film are formed by sputtering, but any sputtering such as DC sputtering, RF sputtering, and ion beam sputtering is applicable. In the case of using a target with low conductivity (such as a silicon target or a silicon compound target that does not contain a metalloid element or has a low content), it is preferable to apply RF sputtering or ion beam sputtering, but the film formation rate is considered. Then, it is more preferable to apply RF sputtering.

  In the step of forming the low transmission layer and the high transmission layer in the phase soft film by sputtering, both the low transmission layer and the high transmission layer are formed in the same film formation chamber and in different film formation chambers. Applicable. In addition, when the low transmission layer and the high transmission layer are formed in the same film formation chamber, the low transmission layer and the high transmission layer may be formed with the same target, or may be formed with different targets. Is also applicable. In the case where the low permeable layer and the high permeable layer are formed in different film forming chambers, it is preferable that the film forming chambers are connected to each other through, for example, separate vacuum chambers. In this case, it is preferable to connect the load lock chamber through which the translucent substrate in the atmosphere is introduced into the vacuum chamber to the vacuum chamber. In addition, it is preferable to provide a transfer device (robot hand) for transferring the translucent substrate between the load lock chamber, the vacuum chamber, and each film forming chamber.

  In order for the phase shift film in the mask blank of the present invention to effectively function the phase shift effect, the transmittance with respect to ArF exposure light is preferably 1% or more, and more preferably 2% or more. Further, the phase shift film is preferably adjusted so that the transmittance with respect to ArF exposure light is 30% or less, more preferably 20% or less, and further preferably 18% or less. The phase shift film is adjusted so that the phase difference generated between the transmitted ArF exposure light and the light that has passed through the air by the same distance as the thickness of the phase shift film is in the range of 170 to 190 degrees. It is preferable that

  In the mask blank of the present invention, a light shielding film is preferably laminated on the phase shift film. In general, in a transfer mask, the outer peripheral region of a region where a transfer pattern is formed (transfer pattern forming region) is formed by exposure light transmitted through the outer peripheral region when exposed and transferred to a resist film on a semiconductor wafer using an exposure apparatus. It is required to secure an optical density (OD) of a predetermined value or higher so that the resist film is not affected. This also applies to the phase shift mask. Usually, it is desirable that the OD is 3.0 or more in the outer peripheral region of the transfer mask including the phase shift mask, and an OD of at least 2.8 or more is required. As described above, the phase shift film has a function of transmitting exposure light with a predetermined transmittance, and it is difficult to ensure a predetermined optical density with only the phase shift film. For this reason, it is desired that a light shielding film is laminated on the phase shift film at the stage of manufacturing the mask blank in order to ensure an insufficient optical density. By adopting such a mask blank configuration, if the light shielding film in the area (basically the transfer pattern forming area) where the phase shift effect is used is removed in the course of manufacturing the phase shift film, the outer peripheral area has a predetermined value. A phase shift mask having a sufficient optical density can be manufactured.

  As the light shielding film, both a single layer structure and a laminated structure of two or more layers are applicable. In addition, each layer of the light shielding film having a single layer structure and the light shielding film having a laminated structure of two or more layers may have a composition having almost the same composition in the thickness direction of the film or the layer, and the composition gradient in the thickness direction of the layer It may be the configuration.

  In the case where another film is not interposed between the light-shielding film and the phase-shift film, it is necessary to apply a material having sufficient etching selectivity with respect to an etching gas used when forming a pattern on the phase-shift film. There is. In this case, the light shielding film is preferably formed of a material containing chromium. Examples of the material containing chromium forming the light-shielding film include a material containing one or more elements selected from oxygen, nitrogen, carbon, boron and fluorine in addition to chromium metal. In general, a chromium-based material is etched with a mixed gas of a chlorine-based gas and an oxygen gas, but chromium metal does not have a high etching rate with respect to this etching gas. In consideration of increasing the etching rate of the mixed gas of chlorine gas and oxygen gas with respect to the etching gas, the material for forming the light shielding film is one or more elements selected from chromium, oxygen, nitrogen, carbon, boron and fluorine. It is preferable to use a material containing. Moreover, you may make the material containing chromium which forms a light shielding film contain one or more elements among molybdenum and tin. By including one or more elements of molybdenum and tin, the etching rate for the mixed gas of chlorine-based gas and oxygen gas can be further increased.

  On the other hand, in the mask blank of the present invention, when another film is interposed between the light-shielding film and the phase shift film, the other film (etching stopper / etching mask film) is made of the material containing chromium. It is preferable that the light shielding film is formed of a material containing silicon. A material containing chromium is etched by a mixed gas of a chlorine-based gas and an oxygen gas, but a resist film formed of an organic material is easily etched by this mixed gas. A material containing silicon is generally etched with a fluorine-based gas or a chlorine-based gas. Since these etching gases basically do not contain oxygen, the amount of reduction in the resist film formed of an organic material can be reduced as compared with the case of etching with a mixed gas of chlorine gas and oxygen gas. For this reason, the film thickness of the resist film can be reduced.

  The material containing silicon that forms the light-shielding film may contain a transition metal or a metal element other than the transition metal. This is because, when a phase shift mask is produced from this mask blank, the pattern formed by the light shielding film is basically a light shielding band pattern in the outer peripheral region, and is irradiated with ArF exposure light as compared with the transfer pattern forming region. This is because it is rare that the integrated amount is small or the light-shielding film remains in a fine pattern, and even if ArF light resistance is low, a substantial problem hardly occurs. Further, when the transition metal is contained in the light shielding film, the light shielding performance is greatly improved as compared with the case where the transition metal is not contained, and the thickness of the light shielding film can be reduced. As transition metals to be included in the light shielding film, transition metals include molybdenum (Mo), tantalum (Ta), tungsten (W), titanium (Ti), chromium (Cr), hafnium (Hf), nickel (Ni), Any one metal such as vanadium (V), zirconium (Zr), ruthenium (Ru), rhodium (Rh), niobium (Nb), palladium (Pd), or an alloy of these metals can be given.

  In a mask blank having a light shielding film laminated on the phase shift film, an etching mask film formed of a material having etching selectivity with respect to an etching gas used when etching the light shielding film on the light shielding film. Further, it is more preferable to have a laminated structure. Since the light-shielding film must have a function of ensuring a predetermined optical density, there is a limit to reducing the thickness thereof. It is sufficient that the etching mask film has a film thickness that can function as an etching mask until dry etching for forming a pattern on the light shielding film immediately below is completed. I do not receive it. For this reason, the thickness of the etching mask film can be significantly reduced as compared with the thickness of the light shielding film. The resist film made of an organic material has a thickness sufficient to function as an etching mask until dry etching for forming a pattern on the etching mask film is completed. In addition, the thickness of the resist film can be reduced.

When the light shielding film is formed of a material containing chromium, the etching mask film is preferably formed of the material containing silicon. Note that the etching mask film in this case tends to have low adhesion to the organic material resist film, and therefore the surface of the etching mask film is subjected to HMDS (Hexamethyldisilazane) treatment to improve surface adhesion. preferable. In this case, the etching mask film is more preferably formed of SiO ₂ , SiN, SiON or the like. In addition to the above, a material containing tantalum is also applicable as an etching mask film material when the light shielding film is formed of a material containing chromium. Examples of the material containing tantalum in this case include a material in which tantalum contains one or more elements selected from nitrogen, oxygen, boron, and carbon in addition to tantalum metal. Examples of the material include Ta, TaN, TaON, TaBN, TaBON, TaCN, TaCON, TaBCN, TaBOCN, and the like. On the other hand, when the light shielding film is formed of a material containing silicon, the etching mask film is preferably formed of the material containing chromium.

  In the mask blank of the present invention, a material having etching selectivity for both the light-transmitting substrate and the phase shift film between the light-transmitting substrate and the phase shift film (the material containing chromium, for example, Cr, CrN, An etching stopper film made of CrC, CrO, CrON, CrC or the like may be formed.

  In the mask blank of the present invention, it is preferable that a resist film of an organic material is formed with a film thickness of 100 nm or less in contact with the surface of the etching mask film. In the case of a fine pattern corresponding to the DRAM hp32 nm generation, a transfer pattern (phase shift pattern) to be formed on the etching mask film may be provided with SRAF (Sub-Resolution Assist Feature) having a line width of 40 nm. However, even in this case, since the cross-sectional aspect ratio of the resist pattern can be reduced to 1: 2.5, it is possible to prevent the resist pattern from collapsing or detaching during development or rinsing of the resist film. it can. The resist film preferably has a film thickness of 80 nm or less.

  The phase shift mask of the present invention is characterized in that a transfer pattern is formed on the phase shift film of the mask blank. Moreover, the manufacturing method of the phase shift mask of this invention has the process of forming a transfer pattern in the phase shift film of the mask blank manufactured by the said manufacturing method. In the phase shift mask of the present invention, since the material constituting the phase shift film itself is a material having high light resistance against ArF exposure light, a process for improving ArF light resistance is performed after forming a pattern on the phase shift film. Can be omitted.

  FIG. 1 is a cross-sectional view showing a configuration of a mask blank 100 according to an embodiment of the present invention. In this mask blank 100, a phase shift film 2 in which a low transmission layer 21, a high transmission layer 22, and an uppermost layer 23 are stacked in this order, a light shielding film 3, and an etching mask film 4 are stacked on a translucent substrate 1. It has a configuration. On the other hand, FIG. 2 is sectional drawing which shows the structure of the mask blank 101 which is another embodiment of this invention. The mask blank 101 includes a phase shift film 2 in which a high transmission layer 22, a low transmission layer 21, a high transmission layer 22, a low transmission layer 21 and an uppermost layer 23 are laminated in this order on a light transmitting substrate 1, and a light shielding film. 3 and the etching mask film 4 are laminated. Details of each configuration of the mask blanks 100 and 101 are as described above. Hereinafter, according to the manufacturing process shown in FIG. 3, an example of the manufacturing method of the phase shift mask of this invention is demonstrated. In this example, a material containing chromium is applied to the light shielding film, and a material containing silicon is applied to the etching mask film.

  First, a resist film was formed by spin coating in contact with the etching mask film 4 in the mask blank 100. Next, the resist film is exposed and drawn with a first pattern, which is a transfer pattern (phase shift pattern) to be formed on the phase shift film, and further subjected to a predetermined process such as a development process to have a phase shift pattern. A first resist pattern 5a was formed (see FIG. 3A). Subsequently, dry etching using a fluorine-based gas was performed using the first resist pattern 5a as a mask to form the first pattern on the etching mask film 4 (etching mask pattern 4a) (see FIG. 3B). .

  Next, after removing the resist pattern 5a, dry etching using a mixed gas of chlorine gas and oxygen gas is performed using the etching mask pattern 4a as a mask to form a first pattern on the light shielding film 3 (light shielding). Film pattern 3a) (see FIG. 3C). Subsequently, dry etching using a fluorine-based gas is performed using the light-shielding pattern 3a as a mask to form a first pattern on the phase shift film 2 (phase shift pattern 2a), and at the same time, the etching mask pattern 4a is also removed ( (Refer FIG.3 (d)).

  Next, a resist film was formed on the mask blank 100 by a spin coating method. Next, a second pattern, which is a pattern (light-shielding pattern) to be formed on the light-shielding film, is exposed and drawn on the resist film, and a predetermined process such as a development process is further performed, so that the second resist having the light-shielding pattern is obtained. Pattern 6b was formed. Subsequently, using the second resist pattern 6b as a mask, dry etching using a mixed gas of chlorine-based gas and oxygen gas was performed to form a second pattern (light-shielding pattern 3b) on the light-shielding film 3 (FIG. 3). (See (e)). Further, the second resist pattern 6b was removed, and a predetermined process such as cleaning was performed to obtain the phase shift mask 200 (see FIG. 3F).

The chlorine-based gas used in the dry etching is not particularly limited as long as it contains Cl. For example, a chlorine-based _{gas, Cl 2, SiCl 2, CHCl} 3, CH 2 Cl 2, CCl 4, BCl 3 and the like. Further, the fluorine-based gas used in the dry etching is not particularly limited as long as F is contained. For example, a fluorine-based _{gas, CHF 3, CF 4, C} 2 F 6, C 4 F 8, SF 6 and the like. In particular, since the fluorine-based gas not containing C has a relatively low etching rate with respect to the glass substrate, damage to the glass substrate can be further reduced.

  The phase shift mask of the present invention can suppress the CD change (thickening) of the phase shift pattern within a small range even when the phase shift mask has been subjected to the integrated irradiation with the exposure light of the ArF excimer laser. For this reason, even if the phase shift mask after this integrated irradiation is set on the mask stage of an exposure apparatus using ArF excimer laser as exposure light, and the phase shift pattern is exposed and transferred to the resist film on the semiconductor device, The pattern can be transferred to the resist film with sufficient accuracy to satisfy the design specifications.

Furthermore, the semiconductor device manufacturing method of the present invention is characterized in that a pattern is exposed and transferred onto a resist film on a semiconductor substrate using the phase shift mask manufactured using the phase shift mask or the mask blank. Yes. Since the phase shift mask and the mask blank of the present invention have the effects as described above, the present invention after the exposure light of the ArF excimer laser is integratedly applied to the mask stage of the exposure apparatus using the ArF excimer laser as the exposure light. Even if the phase shift mask is set and the phase shift pattern is exposed and transferred to the resist film on the semiconductor device, the pattern can be transferred to the resist film on the semiconductor device with sufficient accuracy to satisfy the design specifications. For this reason, when the circuit pattern is formed by dry etching the lower layer film using this resist film pattern as a mask, a highly accurate circuit pattern free from wiring short-circuiting or disconnection due to insufficient accuracy can be formed.

Hereinafter, the embodiment of the present invention will be described more specifically with reference to examples.
Example 1
[Manufacture of mask blanks]
A translucent substrate 1 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 was prepared. The translucent substrate 1 had its end face and main surface polished to a predetermined surface roughness, and then subjected to a predetermined cleaning process and a drying process.

Next, the translucent substrate 1 is installed in a single wafer RF sputtering apparatus, and a mixed gas of argon (Ar) and nitrogen (N ₂ ) (flow rate ratio Ar: N ₂ = 2) is used using a silicon (Si) target. : 3, pressure = 0.035 Pa) is used as a sputtering gas, the power of the RF power supply is set to 2.8 kW, and the low-transmission layer 21 made of silicon and nitrogen is formed on the translucent substrate 1 by reactive sputtering (RF sputtering). (Si: N = 59 at%: 41 at%) was formed with a thickness of 12 nm. Only the low transmission layer 21 is formed on the main surface of another translucent substrate under the same conditions, and the optical characteristics of the low transmission layer 21 are measured using a spectroscopic ellipsometer (M-2000D manufactured by JA Woollam). When the characteristics were measured, the refractive index n at a wavelength of 193 nm was 1.85, and the extinction coefficient k was 1.70. Incidentally, the conditions used in forming the low-permeability layer 21, in advance at the single-wafer RF sputtering apparatus used, the N ₂ gas in the mixed gas of Ar gas and N ₂ gas in the sputtering gas The relationship between the flow rate ratio and the film formation rate is verified, and film formation conditions such as a flow rate ratio that enables stable film formation in the metal mode region are selected. The composition of the low transmission layer 21 is a result obtained by measurement by X-ray photoelectron spectroscopy (XPS). The same applies to other films.

Next, the translucent substrate 1 on which the low transmission layer 21 is laminated is installed in a single wafer RF sputtering apparatus, and a mixed gas of argon (Ar) and nitrogen (N ₂ ) using a silicon (Si) target. (Flow ratio Ar: N ₂ = 1: 3, pressure = 0.09 Pa) is used as a sputtering gas, the power of the RF power source is set to 2.8 kW, and silicon is deposited on the low transmission layer 21 by reactive sputtering (RF sputtering). Then, a highly transmissive layer 22 (Si: N = 46 at%: 54 at%) made of nitrogen was formed to a thickness of 55 nm. Only the highly transmissive layer 22 is formed on the main surface of another translucent substrate under the same conditions, and the optical property of the highly transmissive layer 22 is measured using a spectroscopic ellipsometer (M-2000D manufactured by JA Woollam). When the characteristics were measured, the refractive index n at a wavelength of 193 nm was 2.52, and the extinction coefficient k was 0.39. Incidentally, the conditions used in forming the high-permeability layer 22, in advance at the single-wafer RF sputtering apparatus used, the N ₂ gas in the mixed gas of Ar gas and N ₂ gas in the sputtering gas The relationship between the flow rate ratio and the film formation rate is verified, and film formation conditions such as a flow rate ratio capable of stably forming a film in the reaction mode (poison mode) region are selected.

Next, the translucent substrate 1 in which the low transmissive layer 21 and the high transmissive layer 22 are stacked is installed in a single wafer RF sputtering apparatus, and a silicon dioxide (SiO ₂ ) target is used and an argon (Ar) gas ( The pressure = 0.03 Pa) was used as the sputtering gas, the power of the RF power source was set to 1.5 kW, and the uppermost layer 23 made of silicon and oxygen was formed to a thickness of 4 nm on the highly transmissive layer 22 by RF sputtering. Only the uppermost layer 23 is formed on the main surface of another translucent substrate under the same conditions, and the optical property of the uppermost layer 23 is measured using a spectroscopic ellipsometer (M-2000D manufactured by JA Woollam). When the characteristics were measured, the refractive index n at a wavelength of 193 nm was 1.56, and the extinction coefficient k was 0.00.

  The phase shift film 2 composed of the low transmission layer 21, the high transmission layer 22, and the uppermost layer 23 was formed on the translucent substrate 1 by the above procedure. When the transmittance and phase difference at the wavelength of the ArF excimer laser light (about 193 nm) were measured with respect to this phase shift film 2 using a phase shift amount measuring device, the transmittance was 5.97% and the phase difference was 177.7. It was a degree.

Next, the translucent substrate 1 on which the phase shift film 2 is formed is installed in a single-wafer DC sputtering apparatus, and using a chromium (Cr) target, argon (Ar), carbon dioxide (CO ₂ ), nitrogen ( N ₂ ) and helium (He) mixed gas (flow ratio Ar: CO ₂ : N ₂ : He = 22: 39: 6: 33, pressure = 0.2 Pa) is used as the sputtering gas, and the power of the DC power source is 1. The lowermost layer of the light shielding film 3 made of CrOCN was formed to a thickness of 30 nm on the phase shift film 2 by reactive sputtering (DC sputtering).

Next, using the same chromium (Cr) target, a mixed gas of argon (Ar) and nitrogen (N ₂ ) (flow rate ratio Ar: N ₂ = 83: 17, pressure = 0.1 Pa) is used as a sputtering gas, and a DC power source The lower layer of the light-shielding film 3 made of CrOCN was formed to a thickness of 4 nm on the phase shift film 2 by reactive sputtering (DC sputtering) with a power of 1.4 kW.

Next, using the same chromium (Cr) target, a mixed gas of argon (Ar), carbon dioxide (CO ₂ ), nitrogen (N ₂ ), and helium (He) (flow rate ratio: Ar: CO ₂ : N ₂ : He = 21: 37: 11: 31, pressure = 0.2 Pa) as the sputtering gas, the power of the DC power source is 1.9 kW, and the light-shielding film made of CrOCN is formed on the phase shift film 2 by reactive sputtering (DC sputtering). The upper layer of 3 was formed with a thickness of 14 nm. By the above procedure, the light-shielding film 3 made of a chromium-based material having a three-layer structure of the lowermost layer made of CrOCN, the lower layer made of CrN, and the upper layer made of CrOCN was formed with a total film thickness of 48 nm from the phase shift film 2 side.

Further, the translucent substrate 1 in which the phase shift film 2 and the light shielding film 3 are laminated is installed in a single wafer RF sputtering apparatus, and a silicon dioxide (SiO ₂ ) target is used, and argon (Ar) gas (pressure = pressure = 0.03 Pa) was used as the sputtering gas, the power of the RF power source was set to 1.5 kW, and the etching mask film 4 made of silicon and oxygen was formed to a thickness of 5 nm on the high transmission layer 22 by RF sputtering. By the above procedure, a mask blank 100 having a structure in which the phase shift film 2 having the three-layer structure, the light shielding film 3 and the etching mask film 4 are laminated on the light transmitting substrate 1 was manufactured.

[Manufacture of phase shift mask]
Next, using the mask blank 100 of Example 1, the phase shift mask 200 of Example 1 was produced according to the following procedure. First, the surface of the etching mask film 4 was subjected to HMDS treatment. Subsequently, a resist film made of a chemically amplified resist for electron beam drawing with a film thickness of 80 nm was formed in contact with the surface of the etching mask film 4 by spin coating. Next, a first pattern, which is a phase shift pattern to be formed on the phase shift film, is drawn on the resist film by electron beam, predetermined development processing and cleaning processing are performed, and the first pattern having the first pattern is obtained. The resist pattern 5a) was formed (see FIG. 3A).

Next, dry etching using CF ₄ gas was performed using the first resist pattern 5a as a mask to form a first pattern (etching mask pattern 4a) on the etching mask film 4 (see FIG. 3B). .

Next, the first resist pattern 5a was removed. Subsequently, dry etching using a mixed gas of chlorine and oxygen (gas flow ratio Cl ₂ : O ₂ = 4: 1) is performed using the etching mask pattern 4 a as a mask to form a first pattern on the light shielding film 3. (Light shielding pattern 3a) (see FIG. 3C).

Next, dry etching using a fluorine-based gas (SF ₆ + He) is performed using the light shielding pattern 3a as a mask to form a first pattern on the phase shift film 2 (phase shift pattern 2a), and at the same time, an etching mask pattern 4a was removed (see FIG. 3 (d)).

Next, a resist film made of a chemically amplified resist for electron beam drawing was formed on the light-shielding film pattern 3a with a film thickness of 150 nm by spin coating. Next, a second pattern, which is a pattern (light-shielding pattern) to be formed on the light-shielding film, is exposed and drawn on the resist film, and a predetermined process such as a development process is further performed, so that the second resist having the light-shielding pattern is obtained. Pattern 6b was formed. Subsequently, dry etching using a mixed gas of chlorine and oxygen (gas flow ratio Cl ₂ : O ₂ = 4: 1) is performed using the second resist pattern 6 b as a mask, and the second pattern is formed on the light-shielding film 3. Was formed (light shielding pattern 3b) (see FIG. 3E). Further, the second resist pattern 6b was removed, and a predetermined process such as cleaning was performed to obtain the phase shift mask 200 (see FIG. 3F).

When the mask pattern was inspected by the mask inspection apparatus on the manufactured halftone phase shift mask 200 of Example 1, it was confirmed that a fine pattern was formed within the allowable range from the design value. Next, a process of irradiating ArF excimer laser light with an integrated dose of 20 kJ / cm ² was performed on the phase shift pattern of the halftone phase shift mask 200 of Example 1. The CD change amount of the phase shift pattern before and after this irradiation treatment was about 2 nm, and the CD change amount was within a range usable as a phase shift mask.

For the halftone phase shift mask 200 of Example 1 after the irradiation treatment of ArF excimer laser light, the resist film on the semiconductor device is exposed to light having a wavelength of 193 nm by using AIMS 193 (manufactured by Carl Zeiss). The transferred image was simulated when exposed and transferred. When the exposure transfer image of this simulation was verified, the design specifications were sufficiently satisfied. From this result, even if the phase shift mask of Example 1 after the ArF excimer laser is irradiated with an integrated dose of 20 kJ / cm ² is set on the mask stage of the exposure apparatus and exposed and transferred to the resist film on the semiconductor device It can be said that the circuit pattern finally formed on the semiconductor device can be formed with high accuracy.

(Example 2)
[Manufacture of mask blanks]
A translucent substrate 1 was prepared in the same procedure as in Example 1. Next, the translucent substrate 1 is installed in a single wafer RF sputtering apparatus, and the film forming conditions are the same as those of the high transmission layer 22 of Example 1, but the thickness is changed to 18 nm and the high transmission layer 22 is formed. Formed. As for the optical characteristics of the high transmission layer 22, the refractive index n at a wavelength of 193 nm was 2.52 and the extinction coefficient k was 0.39, as in the high transmission layer 22 of Example 1.

  Next, the translucent substrate 1 on which the high transmission layer 22 is laminated is installed in a single wafer RF sputtering apparatus, and the film formation conditions are the same as those of the low transmission layer 21 of Example 1, but the thickness is The low transmission layer 21 was formed by changing the thickness to 7 nm. As for the optical characteristics of the low transmission layer 21, the refractive index n at a wavelength of 193 nm was 1.85 and the extinction coefficient k was 1.70 as in the low transmission layer 21 of Example 1.

  Next, the translucent substrate 1 in which the high transmission layer 22 and the low transmission layer 21 are laminated is installed in a single wafer RF sputtering apparatus, and the film formation conditions are the same as those of the high transmission layer 22 of Example 1. However, the thickness was changed to 18 nm to form the highly transmissive layer 22. The optical characteristics of the high transmission layer 22 are the same as those of the first high transmission layer 22.

  Next, the translucent substrate 1 in which the high transmission layer 22, the low transmission layer 21, and the high transmission layer 22 are laminated in this order is installed in a single wafer RF sputtering apparatus, and the same as the low transmission layer 21 of the first embodiment. The low transmission layer 21 was formed with the thickness changed to 7 nm. The optical characteristics of the low transmission layer 21 are the same as those of the second low transmission layer 21.

  Next, the translucent substrate 1 in which the high transmission layer 22, the low transmission layer 21, the high transmission layer 22 and the low transmission layer 21 are sequentially laminated is installed in the single wafer RF sputtering apparatus. Although the film forming conditions were the same as those of the transmissive layer 22, the uppermost layer 23 was formed by changing the thickness to 18 nm. At this time, the optical characteristics of the uppermost layer 23 are the same as those of the first highly transmissive layer 22. Next, an oxidation treatment using ozone was performed on the uppermost layer 23 on the translucent substrate to form an oxide layer on the surface layer of the uppermost layer 23. Thereby, the uppermost layer became a composition gradient film having a tendency that the oxygen content increased as the distance from the translucent substrate side increased.

  By the above procedure, the phase shift film 2 having a five-layer structure including the high transmission layer 22, the low transmission layer 21, the high transmission layer 22, the low transmission layer 21 and the uppermost layer 23 was formed on the translucent substrate 1. When the transmittance and phase difference at the wavelength of the ArF excimer laser light (about 193 nm) were measured for this phase shift film 2 with a phase shift amount measuring device, the transmittance was 5.91% and the phase difference was 181.2. It was a degree.

  Next, a light-shielding film 3 made of a chromium-based material having a three-layer structure was formed on the phase shift film 2 with a total thickness of 48 nm by the same procedure as in Example 1. Subsequently, an etching mask film 4 made of silicon and oxygen was formed to a thickness of 5 nm on the light shielding film 3 in the same procedure as in Example 1. By the above procedure, the mask blank 101 of Example 2 having a structure in which the phase shift film 2, the light-shielding film 3, and the etching mask film 4 having a five-layer structure were laminated on the translucent substrate 1 was manufactured.

[Manufacture of phase shift mask]
Next, using the mask blank 101 of Example 2, the phase shift mask 200 of Example 2 was produced in the same procedure as in Example 1. When the mask pattern was inspected by the mask inspection apparatus on the manufactured halftone phase shift mask 200 of Example 2, it was confirmed that a fine pattern was formed within the allowable range from the design value. Next, the ArF excimer laser beam was irradiated to the phase shift pattern of the halftone phase shift mask 200 of Example 2 at an integrated dose of 20 kJ / cm ² . The CD change amount of the phase shift pattern before and after this irradiation treatment was about 2 nm, and the CD change amount was within a range usable as a phase shift mask.

For the halftone phase shift mask 200 of Example 2 after the irradiation process of ArF excimer laser light, AIMS 193 (manufactured by Carl Zeiss) was used to expose the resist film on the semiconductor device with exposure light having a wavelength of 193 nm. The transferred image was simulated when exposed and transferred. When the exposure transfer image of this simulation was verified, the design specifications were sufficiently satisfied. From this result, even if the phase shift mask of Example 2 after the ArF excimer laser was irradiated at an integrated dose of 20 kJ / cm ² was set on the mask stage of the exposure apparatus and transferred to the resist film on the semiconductor device, It can be said that the circuit pattern finally formed on the semiconductor device can be formed with high accuracy.

(Comparative Example 1)
[Manufacture of mask blanks]
A translucent substrate 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 was prepared in the same procedure as in Example 1. Next, a translucent substrate is installed in a single wafer DC sputtering apparatus, and a mixed sintering target (Mo: Si = 12 at%: 88 at%) of molybdenum (Mo) and silicon (Si) is used to form argon ( Reactive sputtering (DC sputtering) using a mixed gas of Ar), nitrogen (N ₂ ), and helium (He) (flow ratio Ar: N ₂ : He = 8: 72: 100, pressure = 0.2 Pa) as a sputtering gas Thus, a phase shift film made of molybdenum, silicon, and nitrogen was formed on the translucent substrate 1 to a thickness of 69 nm.

  Next, heat treatment in the atmosphere was performed on the phase shift film on the light-transmitting substrate. This heat treatment was performed at 450 ° C. for 1 hour. With respect to the phase shift film of Comparative Example 1 after this heat treatment was performed, the transmittance and phase difference at the wavelength of the ArF excimer laser light (about 193 nm) were measured with a phase shift amount measuring device. The phase difference was 6.02% and 177.9 degrees.

  Next, a light shielding film of a chromium-based material having a three-layer structure was formed on the phase shift film with a total film thickness of 48 nm in the same procedure as in Example 1. Subsequently, an etching mask film made of silicon and oxygen was formed to a thickness of 5 nm on the light shielding film in the same procedure as in Example 1. The mask blank of the comparative example 1 provided with the structure which laminated | stacked the phase shift film which consists of MoSiN, the light shielding film, and the etching mask film | membrane on the translucent board | substrate with the above procedure was manufactured.

[Manufacture of phase shift mask]
Next, using the mask blank of Comparative Example 1, a phase shift mask of Comparative Example 1 was produced in the same procedure as in Example 1. When the mask pattern was inspected by the mask inspection apparatus on the manufactured halftone phase shift mask of Comparative Example 1, it was confirmed that a fine pattern was formed within the allowable range from the design value. Next, the ArF excimer laser light was irradiated to the phase shift pattern of the halftone phase shift mask of Comparative Example 1 at an integrated dose of 20 kJ / cm ² . The CD change amount of the phase shift pattern before and after this irradiation treatment was 20 nm or more, which was a CD change amount greatly exceeding the range usable as a phase shift mask.

For the halftone phase shift mask 200 of Comparative Example 1 after the ArF excimer laser light irradiation treatment, AIMS 193 (manufactured by Carl Zeiss) was used to expose the resist film on the semiconductor device with exposure light having a wavelength of 193 nm. The transferred image was simulated when exposed and transferred. When the exposure transfer image of this simulation was verified, the design specification could not be satisfied due to the influence of the CD change of the phase shift pattern. From this result, when the phase shift mask of Comparative Example 1 after the ArF excimer laser was irradiated at an integrated dose of 20 kJ / cm ² was set on the mask stage of the exposure apparatus and transferred to the resist film on the semiconductor device, It is expected that the circuit pattern finally formed on the semiconductor device will be disconnected or short-circuited.

DESCRIPTION OF SYMBOLS 1 Translucent substrate 2 Phase shift film 2a Phase shift pattern 21 Low transmission layer 22 High transmission layer 23 Uppermost layer 3 Light shielding film 3a, 3b Light shielding pattern 4 Etching mask film 4a Etching mask pattern 5a First resist pattern 6b Second resist pattern Resist pattern 100, 101 Mask blank 200 Transfer mask

Claims (12)

A mask blank provided with a phase shift film on a translucent substrate,
The phase shift film transmits ArF exposure light at a transmittance of 1% or more and 30% or less, and ArF exposure light that passes through the phase shift film passes through the air by the same distance as the thickness of the phase shift film. Having a function of causing a phase difference of not less than 170 degrees and not more than 190 degrees with the passing ArF exposure light;
The phase shift film includes a structure in which a low transmission layer and a high transmission layer are laminated,
The low-permeability layer and the high-permeability layer are formed of a material composed of silicon and nitrogen, or a material containing one or more elements selected from a metalloid element, a non-metal element, and a rare gas in the material,
The low permeability layer, the nitrogen content as compared with the high permeability layer is relatively rather small,
The mask blank, wherein the low-permeability layer and the high-permeability layer have an oxygen content of 10 atomic% or less .   The mask blank according to claim 1, wherein a thickness of the high transmission layer is larger than a thickness of the low transmission layer. The low-permeability layer and said high permeability layer, the mask blank according to claim 1 or 2, characterized in that the same configuration elements. Wherein the phase shift film, according to any one of claims 1 to 3, characterized in that it comprises a set of layered structure consisting of the single-layer low-permeability layer and the first layer said high permeability layer of two or more sets Mask blank. The low-permeability layer and said high permeability layer, the mask blank according to any one of claims 1 to 4, characterized in that it is formed of a material consisting of silicon and nitrogen. The low transmission layer is formed of a material having a refractive index n with respect to ArF exposure light of less than 2.5 and an extinction coefficient k of 1.0 or more.
The high permeability layer has a refractive index n with respect to the ArF exposure light 2.5 or more, any of claims 1 to 5 extinction coefficient k is characterized in that it is formed of a material less than 1.0 The mask blank according to crab. The mask blank according to any one of claims 1 to 6 , wherein the phase shift film has a structure in which the high transmission layer and the low transmission layer are stacked in contact with the light transmitting substrate. The mask blank according to any one of claims 1 to 7 , wherein a thickness of any one of the low transmission layer and the high transmission layer is 20 nm or less. The phase shift film contains, at a position farthest from the light-transmitting substrate, a material composed of silicon, nitrogen and oxygen, or one or more elements selected from metalloid elements, nonmetallic elements, and rare gases in the material mask blank according to any one of claims 1 to 8, characterized in that it comprises a top layer formed of a material. The mask blank according to claim 9 , wherein the uppermost layer is formed of a material composed of silicon and oxygen, or a material composed of silicon, nitrogen, and oxygen. Phase shift mask, wherein a transfer pattern to the phase shift film of the mask blank according to any one of claims 1 to 10 is formed. 12. A method of manufacturing a semiconductor device, comprising using the phase shift mask according to claim 11 and exposing and transferring the transfer pattern onto a resist film on a semiconductor substrate.

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