Phase shift mask blank, method for manufacturing phase shift mask, and phase shift mask

Abstract

The present application provides a phase shift mask blank having a phase shift film with good phase control and excellent pattern shape obtained by etching using chlorine-oxygen gas. The phase shift mask blank has a transparent substrate, and a phase shift film formed on the transparent substrate, the phase shift film having a phase difference of 160 to 200° at an exposure wavelength of 200 nm or less and a transmittance of 3 to 15%, the phase shift film sequentially comprising a lower layer and an upper layer from the transparent substrate side, the upper layer containing a transition metal, silicon, nitrogen and / or oxygen, or containing silicon, nitrogen and / or oxygen, the lower layer containing chromium, silicon, nitrogen and / or oxygen, the content ratio of silicon being 3% or more and less than 15% relative to the total content of chromium and silicon of the lower layer, the content ratio of oxygen being less than 1.7 relative to the total content of chromium and silicon, and the etching selectivity ratio of the upper layer to the lower layer in dry etching of fluorine type being 10 or more.

Description

TECHNICAL FIELD

[0001] The present application relates to a phase shift mask blank, a manufacturing method of a phase shift mask, and a phase shift mask, which are useful for manufacturing a semiconductor integrated circuit or the like. BACKGROUND

[0002] In photolithography technology used for semiconductor technology, a phase shift method is used as one of resolution enhancement techniques. The phase shift method is, for example, a method of using a photomask in which a phase shift film is formed on a substrate that is transparent under exposure light, and is a method of improving contrast using interference of light, for which the phase difference between light transmitted through the phase shift film and exposure light transmitted through a portion where the phase shift film is not formed, that is, the phase difference between light transmitted through the phase shift film and exposure light that has passed through air having a length equal to the thickness of the phase shift film, is approximately 180°.

[0003] As one of photomasks to which the phase shift method is applied, there is a half-tone phase shift mask. The half-tone phase shift mask is a mask pattern in which a half-tone phase shift film is formed on a substrate such as quartz that is transparent under exposure light, and the phase difference between light transmitted through the half-tone phase shift film and light transmitted through a portion where the phase shift film is not formed is approximately 180°, and the half-tone phase shift film has a transmittance to the extent that exposure does not substantially affect it. Heretofore, as a phase shift film of a phase shift mask, a film containing molybdenum and silicon (MoSi type phase shift film) has been mainly used (Patent Document 1).

[0004] PRIOR ART DOCUMENTS

[0005] PATENT DOCUMENTS

[0006] Patent Document 1: Japanese Patent Application Laid-Open (JP-A) No. 7-140635

[0007] Patent Document 2: Japanese Patent Application Laid-Open (JP-A) No. 2007-33469

[0008] Patent Document 3: Japanese Patent Application Laid-Open (JP-A) No. 2007-233179

[0009] Patent Document 4: Japanese Patent Application Laid-Open (JP-A) No. 2007-241065 SUMMARY

[0010] Technical Problem to be Solved by the Invention

[0011] Generally, in a phase shift mask having a MoSi type phase shift film, when the phase shift film is subjected to pattern processing, although etching is performed by using a fluorine-based gas such as SF6or CF4, at this time, the substrate is slightly etched. Therefore, the phase difference between a portion having the phase shift film and a portion not having the phase shift film, and the phase difference of the film itself are different. Therefore, not only is it difficult to correctly control the phase difference, but there is also a technical problem in that it is difficult to correct when a pattern defect occurs.

[0012] To solve this problem, a phase shift mask blank is considered in which the composition of the phase shift film is set to a composition in which a film having different etching characteristics from a chromium film is formed on the substrate side of a film containing silicon such as a MoSi film. A chromium film is generally formed on a film containing silicon, and the chromium film is a film that functions as an etching mask when etching a light shielding film or a phase shift film. The chromium film on the substrate side that is exposed by etching of the film containing silicon is etched using a chlorine-based gas containing chlorine and oxygen or the like while peeling off the chromium light shielding film or the chromium etching mask on the phase shift film (the side away from the substrate). However, at this time, side etching easily occurs in the chromium film on the substrate side, and problems such as pattern collapse easily occur. In particular, when the amount of oxygen or nitrogen is increased in order to increase the transmittance of the chromium film, the amount of side etching further increases.

[0013] The present application was made in view of the above-described technical problems, and aims to provide a phase shift mask blank having a phase shift film that has good phase control and excellent pattern shape obtained by etching using a chlorine-based gas, a phase shift mask, and a manufacturing method of a phase shift mask.

[0014] Technical means for solving the technical problems

[0015] To achieve the above-described object, the present application provides a phase shift mask blank having a transparent substrate and a phase shift film formed on the transparent substrate, wherein the phase shift film has a phase difference of 160 to 200° and a transmittance of 3 to 15% at an exposure wavelength of 200 nm or less, and the phase shift film contains a lower layer and an upper layer in this order from the transparent substrate side, the upper layer contains a transition metal, silicon, nitrogen, and / or oxygen, or contains silicon, nitrogen, and / or oxygen, the lower layer contains chromium, silicon, nitrogen, and / or oxygen, the content ratio of silicon with respect to the total content of chromium and silicon in the lower layer is 3% or more and less than 15%, the content ratio of oxygen with respect to the total content of chromium and silicon is less than 1.7, and the etching selectivity of the upper layer to the lower layer in dry etching using a fluorine-based gas is 10 or more.

[0016] If the above-described phase shift mask blank is used, a phase shift mask blank can be obtained that is capable of forming a phase shift film that has good phase control and excellent pattern shape obtained by etching using a chlorine-based gas, for example, using chlorine and oxygen.

[0017] Further, it is preferable that the transparent substrate be formed of quartz.

[0018] As the transparent substrate, the above-described transparent substrate is suitably used.

[0019] Further, it is preferable that the film thickness of the lower layer be 2 to 10 nm and the film thickness of the upper layer be 50 to 80 nm.

[0020] If the above-described configuration is used, a prescribed transmittance can be easily obtained.

[0021] Further, it is preferable that in the upper layer, the transition metal is molybdenum (Mo), and the content of molybdenum (Mo) is 20% or less relative to the total of silicon (Si) and molybdenum (Mo).

[0022] In the present application, the composition of the upper layer can be set as the above composition.

[0023] Further, it is preferable that the phase shift mask has a light shielding film containing chromium on the phase shift film, and the etching selectivity of the light shielding film to the lower layer in dry etching of the chlorine type is 1.2 or more and 10.0 or less.

[0024] If the light shielding film is as described above, it can be removed together with the lower layer by dry etching of the chlorine type, and the lower layer is not subjected to side etching at this time.

[0025] At this time, it is preferable that a hard mask film containing silicon, oxygen, and / or nitrogen is further provided on the light shielding film.

[0026] If the hard mask film is as described above, it is useful as an etching mask in the formation of a pattern of the light shielding film because the etching characteristics are different from those of the light shielding film containing chromium.

[0027] Further, the present application provides a manufacturing method of a phase shift mask using the above-described phase shift mask blank.

[0028] If the manufacturing method of the phase shift mask is as described above, not only is there no groove in the transparent substrate, but also a phase shift mask having a good pattern shape can be obtained.

[0029] Further, the present application provides a phase shift mask having a transparent substrate, and a phase shift film having a pattern formed on the transparent substrate, the phase shift film having a phase difference of 160 to 200° and a transmittance of 3 to 15% at an exposure wavelength of 200 nm or less, the phase shift film sequentially containing a lower layer and an upper layer from the transparent substrate side, the upper layer containing a transition metal, silicon, nitrogen, and / or oxygen, or containing silicon, nitrogen, and / or oxygen, the lower layer containing chromium, silicon, nitrogen, and / or oxygen, the content of silicon being 3% or more and less than 15% relative to the total of chromium and silicon of the lower layer, the content ratio of oxygen relative to the total content of chromium and silicon being less than 1.7, and the etching selectivity of the upper layer to the lower layer in dry etching of the fluorine type being 10 or more.

[0030] The above-described phase shift mask not only has no groove in the transparent substrate, but also has a good pattern shape.

[0031] Further, it is preferable that the transparent substrate is formed of quartz.

[0032] As the transparent substrate, the above-described transparent substrate is suitably used.

[0033] Further, it is preferable that the lower layer has a film thickness of 2 to 10 nm and the upper layer has a film thickness of 50 to 80 nm.

[0034] If the above configuration is adopted, it is easy to obtain a prescribed transmittance.

[0035] Further, it is preferable that in the upper layer, the transition metal is molybdenum (Mo), and the content of molybdenum (Mo) is 20% or less relative to the total of silicon (Si) and molybdenum (Mo).

[0036] In the present application, the composition of the upper layer can be set as the above composition.

[0037] Further, it is preferable that the phase shift mask has a light shielding film containing chromium on the phase shift film, and the etching selectivity of the light shielding film to the lower layer in chlorine-based dry etching is 1.2 or more and 10.0 or less.

[0038] If the above light shielding film is adopted, it can be removed together with the lower layer by chlorine-based dry etching, and the lower layer is not subjected to side etching at this time.

[0039] Effects of the Invention

[0040] According to the phase shift mask blank of the present application, since a groove is not easily formed in the substrate when the phase shift film is processed in the processing of the photomask pattern, a photomask (phase shift mask) which is easy to adjust the phase difference and has a good pattern shape can be produced. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 is a schematic view showing one example of the phase shift mask blank of the present application.

[0042] Figure 2 is a schematic view showing another example of the phase shift mask blank of the present application.

[0043] Figure 3 is a schematic view showing still another example of the phase shift mask blank of the present application.

[0044] Figure 4 is a schematic view showing an etching device used in the examples and comparative examples.

[0045] EXPLANATION OF REFERENCE NUMERALS

[0046] 1: phase shift film; 2: second layer; 3: third layer; 4: fourth layer; 10: transparent substrate; 11: lower layer; 12: upper layer; 13: light shielding film; 100: phase shift mask blank; 101: chamber; 102: ground wire; 103: lower electrode; 104: antenna coil; 105: substrate to be processed; 1000: dry etching device; RF1, RF2: high frequency power source. DETAILED DESCRIPTION

[0047] As described above, it is required to develop a phase shift mask blank, a phase shift mask, and a manufacturing method of a phase shift mask capable of forming a phase shift film having a good phase control property and an excellent pattern shape obtained by etching using a chlorine-based gas.

[0048] The inventors of the present application have made earnest studies in order to solve the above technical problems, and as a result, have found that by using a phase shift film having a layer (lower layer) containing chromium, silicon, nitrogen and / or oxygen, and further having a layer on the upper layer containing a transition metal, silicon, nitrogen and / or oxygen, or containing silicon, nitrogen and / or oxygen, with the silicon content of the lower layer containing chromium, silicon, nitrogen and / or oxygen being 3% or more and less than 15%, and the ratio of the oxygen content to the total content of chromium and silicon being less than 1.7, a photomask having a good pattern and capable of suppressing side etching of the above lower layer during etching of a chromium light shielding film or a chromium etching mask on the phase shift film using a chlorine-based etchant can be produced, thereby completing the present application.

[0049] That is, the present application provides a phase shift mask blank having a transparent substrate, and a phase shift film formed on the transparent substrate, wherein the phase shift film has a phase difference of 160 to 200° and a transmittance of 3 to 15% at an exposure wavelength of 200 nm or less, and the phase shift film sequentially contains a lower layer and an upper layer from the transparent substrate side, the upper layer contains a transition metal, silicon, nitrogen and / or oxygen, or contains silicon, nitrogen and / or oxygen, the lower layer contains chromium, silicon, nitrogen and / or oxygen, the silicon content with respect to the total of chromium and silicon of the lower layer is 3% or more and less than 15%, the ratio of the oxygen content to the total content of chromium and silicon is less than 1.7, and the etching selectivity of the upper layer to the lower layer in a fluorine-based dry etching is 10 or more.

[0050] Hereinafter, the present application will be described in detail, but the present application is not limited thereto.

[0051] <Phase shift mask blank>

[0052] The phase shift mask blank of the present application has a phase shift film formed on a transparent substrate such as a quartz substrate. In addition, the phase shift mask of the present application described later has a mask pattern (photomask pattern) of a phase shift film formed on a transparent substrate such as a quartz substrate.

[0053] <Transparent substrate>

[0054] In the present application, the transparent substrate is not particularly limited, and for example, it is appropriate to be a transparent substrate called a 6025 substrate of 6 inches square and 0.25 inches thick as defined in the SEMI standard, and when using the SI unit system, it is usually written as a transparent substrate of 152 mm square and 6.35 mm thick. As the transparent substrate, a quartz substrate is preferred.

[0055] <Phase shift film>

[0056] The phase shift film of the present invention exhibits a phase difference of 160 to 200° between light passing through the phase shift film and light passing through a portion of the film having the same thickness as the phase shift film, and a transmittance of 3 to 15%, at an exposure wavelength of 200 nm or less, particularly 193 nm (ArF). The film comprises, from the transparent substrate side, a lower layer containing chromium, silicon, nitrogen, and / or oxygen, and an upper layer containing a transition metal (preferably a transition metal other than chromium), silicon, nitrogen, and / or oxygen, or silicon, nitrogen, and / or oxygen. Furthermore, the silicon content of the lower layer containing chromium, silicon, nitrogen, and / or oxygen is 3% or more and less than 15% relative to the total content of chromium and silicon, and the ratio of the oxygen content to the total content of chromium and silicon is less than 1.7. Furthermore, the etching selectivity between the upper layer and the lower layer in fluorine-based dry etching is 10 or more.

[0057] By proceeding in this manner, a phase shift film can be produced that does not produce grooves in the transparent substrate even when dry-etched with fluorine-based gases, and is also less susceptible to side etching when dry-etched with chlorine-based gases (chlorine-oxygen-based gases). Fluorine-based gases herein refer to fluorine-containing gases such as SF6 and CF4, while chlorine-based gases refer to gases containing chlorine and oxygen, such as those composed of Cl2 and O2. These gases may further contain He, etc. Furthermore, dry etching using fluorine-based gases is referred to herein as fluorine-based dry etching, and dry etching using chlorine-based gases is referred to as chlorine-based dry etching.

[0058] The lower film contains chromium, silicon, nitrogen, and / or oxygen. The silicon content is 3% or more and less than 15% relative to the combined chromium and silicon content of the lower layer, and the ratio of the oxygen content to the combined chromium and silicon content is less than 1.7. Preferably, the silicon content is 3% or more and less than 14% relative to the combined chromium and silicon content of the lower layer, and the ratio of the oxygen content to the combined chromium and silicon content is less than 1.6. More preferably, the silicon content is 5% or more and less than 10% relative to the combined chromium and silicon content of the lower layer, and the ratio of the oxygen content to the combined chromium and silicon content is less than 1.1. Furthermore, the oxygen content in the lower layer is preferably less than 60%, more preferably less than 50%, and even more preferably less than 45%. While oxygen may be absent, a higher oxygen content increases transmittance and facilitates adjustments such as thinning the upper film. Therefore, the oxygen content is preferably 30% or more, more preferably 35% or more, and even more preferably 40% or more. The nitrogen content is preferably 0% or more and less than 52%. Here, the contents of silicon, oxygen, and nitrogen are ratios of the number of atoms, and can be determined by, for example, measurement using XPS.

[0059] Further, the lower layer film is more preferably any one of a film composed of chromium, silicon, nitrogen, and oxygen; a film composed of chromium, silicon, and nitrogen; and a film composed of chromium, silicon, and oxygen. The above film can further contain carbon, hydrogen, or the like.

[0060] The upper layer film contains a transition metal, silicon, nitrogen, and / or oxygen, or contains silicon, nitrogen, and / or oxygen. That is, the upper layer film is more preferably any one of a film composed of a transition metal, silicon, nitrogen, and oxygen; a film composed of a transition metal, silicon, and nitrogen; a film composed of a transition metal, silicon, and oxygen; a film composed of silicon, nitrogen, and oxygen; a film composed of silicon and nitrogen; and a film composed of silicon and oxygen. The above film can further contain carbon, hydrogen, or the like.

[0061] As the transition metal, although not particularly limited, for example, molybdenum, zirconium, tantalum, tungsten, chromium, titanium can be used, and a transition metal other than chromium is preferable, and molybdenum is particularly preferable. The ratio of the composition of the transition metal with respect to the total of the transition metal and silicon is preferably 0% or more and 40% or less, and the ratio of oxygen is preferably 0% or more and 70% or less, and the ratio of nitrogen is preferably 0% or more and 60% or less. Here, the ratios of the transition metal, oxygen, and nitrogen are atomic ratios, and can be obtained, for example, by measurement based on XPS.

[0062] In the phase shift film, the lower layer film containing chromium, silicon, nitrogen, and / or oxygen preferably has a thickness of 2 to 10 nm, and the upper layer film containing a transition metal, silicon, nitrogen, and / or oxygen, or containing silicon, nitrogen, and / or oxygen has a thickness of 50 to 80 nm. By being configured in this way, it is easy to obtain a prescribed transmittance.

[0063] The transition metal of the upper layer film containing a transition metal, silicon, nitrogen, and / or oxygen, or containing silicon, nitrogen, and / or oxygen is preferably molybdenum, and the content ratio of molybdenum with respect to the total of silicon and molybdenum is preferably 20% or less.

[0064] The upper layer film containing a transition metal, silicon, nitrogen, and / or oxygen, or containing silicon, nitrogen, and / or oxygen can be etched using a fluorine-based etchant, and the etching selectivity ratio of the upper layer to the lower layer in dry etching using a fluorine-based etchant is preferably 10 or more, and further preferably 15 or more.

[0065] Here, the above etching selectivity ratio in dry etching using a fluorine-based etchant is (etching selectivity ratio) = (etching rate of the upper layer) / (etching rate of the lower layer).

[0066] Further, it is preferable that the phase shift film has a light-shielding film containing chromium on the upper layer, which can be etched using a chlorine-based etchant, and the etching selectivity ratio of the light-shielding film to the lower layer film containing chromium, silicon, nitrogen, and / or oxygen on the transparent substrate using a chlorine-based etchant is 1.2 or more and 10.0 or less.

[0067] Here, the above etching selectivity ratio in dry etching using a chlorine-based etchant is (etching selectivity ratio) = (etching rate of the light-shielding film) / (etching rate of the lower layer).

[0068] Further, it is preferable that a hard mask film containing silicon, oxygen, and / or nitrogen be further provided on the light shielding film. Details of the light shielding film or the hard mask film are described later.

[0069] Here, reference is made to Figure 1 An example of the phase shift mask blank of the present application is described. In the phase shift mask blank 100 of the present application, a lower layer 11 which is a layer containing chromium, silicon, nitrogen, and / or oxygen is formed on a transparent substrate 10, and an upper layer 12 containing a transition metal, silicon, nitrogen, and / or oxygen, or containing silicon, nitrogen, and / or oxygen is formed on the lower layer 11. The phase shift film 1 contains the lower layer 11 and the upper layer 12. Further, a light shielding film 13 can be formed on the phase shift film 1.

[0070] The upper layer 12 is a film which is easily etched by a fluorine-based gas. On the other hand, since the lower layer 11 is a film of the above-described prescribed composition, it is a film which is difficult to be etched by a fluorine-based gas, but can be etched at an appropriate speed by a chlorine-based gas. Therefore, when the phase shift mask is manufactured from the phase shift mask blank 100, and the upper layer 12 of the phase shift film 1 is peeled off by dry etching based on a fluorine-based gas, since the lower layer 11 is present, it is possible to prevent the transparent substrate 10 from being recessed by the dry etching. Also, when the unnecessary portion of the light shielding film 13 is peeled off by a chlorine-based gas, the lower layer 11 is also peeled off at the same time, but since the lower layer 11 has the prescribed composition, side etching does not occur in the lower layer 11.

[0071] <Method for forming phase shift film>

[0072] The phase shift film in the present application can be formed by a publicly known film forming method, and it is preferable to form the film by a sputtering method which easily provides a film having excellent uniformity, and any one of DC sputtering, RF sputtering can be used, but a magnetron sputtering is more preferable. The target material and the sputtering gas can be appropriately selected depending on the layer constitution or composition.

[0073] When the film containing chromium and silicon of the lower layer is formed, it can be provided that a target material composed of chromium and silicon, or a chromium target material and a silicon target material are used as the target material and discharge at the same time by co-sputtering, or it can be provided that a target material composed of chromium and silicon is used instead of at least one of a chromium target material or a silicon target material and discharge at the same time by co-sputtering, or it can be provided that a chromium target material, a silicon target material, and a target material composed of chromium and silicon are used and discharge at the same time by co-sputtering.

[0074] When the film of the upper layer is a film containing silicon without containing a transition metal, a silicon target can be used. When a film containing a transition metal and containing silicon is formed, it can be configured to use a target composed of a transition metal and silicon, or to use co-sputtering in which a transition metal target and a silicon target are used and discharge is performed at the same time, or to use co-sputtering in which at least one of a transition metal target or a silicon target is replaced with a target composed of a transition metal and silicon and discharge is performed at the same time, or to use co-sputtering in which a transition metal target, a silicon target, and a target composed of a transition metal and silicon are used and discharge is performed at the same time.

[0075] In addition, these targets can contain nitrogen, and a target containing nitrogen and a target not containing nitrogen can be used at the same time.

[0076] The content ratio of nitrogen or the content ratio of oxygen of the upper layer and the lower layer can be adjusted by using nitrogen or oxygen, or nitrogen oxide containing nitrogen and oxygen, as a reactive gas in the sputtering gas, and appropriately adjusting the amount of introduction and performing reactive sputtering. Further, in the sputtering gas, as a rare gas, helium, neon, argon, krypton, xenon, or the like can be used.

[0077] <Second layer>

[0078] A second layer composed of a single layer or a plurality of layers can be provided on the phase shift film of the phase shift mask blank of the present application. The second layer is usually provided in a manner adjacent to the phase shift film. As the second layer, specifically, a light shielding film, a combination of a light shielding film and an antireflection film, a processing assist film (etching mask film) that functions as a hard mask in the pattern formation of the phase shift film, or the like can be listed. In addition, when the third layer described later is provided, the second layer can also be used as a processing assist film (etching stopper film) that functions as an etching stopper in the pattern formation of the third layer. As the material of the second layer, a material containing chromium is suitable.

[0079] By providing the second layer containing a light shielding film, a region in which exposure light is completely shielded can be provided in the phase shift mask. The light shielding film and the antireflection film can also be used as a processing assist film in etching.

[0080] (Light shielding film and antireflection film as second layer)

[0081] Although there are many reports on the film formation and materials of light shielding films and antireflection films (for example, Patent Literature 2, Patent Literature 3, and the like), as a film formation of a combination of a light shielding film and an antireflection film that is preferred, for example, a film formation in which a light shielding film of a material containing chromium is provided, and further an antireflection film of a material containing Cr that can reduce reflection from the light shielding film is provided, or the like can be listed. The light shielding film and the antireflection film can each be formed in a single layer, or can be formed in a plurality of layers.

[0082] As the material containing chromium for the light-shielding film or the antireflection film, there can be mentioned chromium itself, chromium oxide (CrO), chromium nitride (CrN), chromium carbide (CrC), chromium oxynitride (CrON), chromium oxycarbide (CrOC), chromium nitride carbide (CrNC), chromium oxynitride carbide (CrONC), and the like. Note that, here, the chemical formula of the material containing chromium shows only the constituent elements, and does not indicate the composition ratio of the constituent elements (the same applies to the material containing chromium hereinafter).

[0083] When the second layer is the light-shielding film or the combination of the light-shielding film and the antireflection film, the content of chromium in the chromium compound of the light-shielding film is preferably 40 atomic % or more, particularly preferably 60 atomic % or more, preferably less than 100 atomic %, particularly preferably 99 atomic % or less, and more preferably 90 atomic % or less. The content of oxygen is preferably 60 atomic % or less, particularly preferably 40 atomic % or less, and more preferably 1 atomic % or more. The content of nitrogen is preferably 50 atomic % or less, particularly preferably 40 atomic % or less, and more preferably 1 atomic % or more. The content of carbon is preferably 20 atomic % or less, particularly preferably 10 atomic % or less, and more preferably 1 atomic % or more when the etching rate needs to be adjusted. In this case, the total content of chromium, oxygen, nitrogen, and carbon is preferably 95 atomic % or more, particularly preferably 99 atomic % or more, and more preferably 100 atomic %.

[0084] Further, when the second layer is the combination of the light-shielding film and the antireflection film, the antireflection film is preferably a chromium compound, and the content of chromium in the chromium compound is preferably 30 atomic % or more, particularly preferably 35 atomic % or more, and preferably 70 atomic % or less, particularly preferably 50 atomic % or less. The content of oxygen is preferably 60 atomic % or less, more preferably 1 atomic % or more, and particularly preferably 20 atomic % or more. The content of nitrogen is preferably 50 atomic % or less, particularly preferably 30 atomic % or less, more preferably 1 atomic % or more, and particularly preferably 3 atomic % or more. The content of carbon is preferably 20 atomic % or less, particularly preferably 5 atomic % or less, and more preferably 1 atomic % or more when the etching rate needs to be adjusted. In this case, the total content of chromium, oxygen, nitrogen, and carbon is preferably 95 atomic % or more, particularly preferably 99 atomic % or more, and more preferably 100 atomic %.

[0085] When the second layer is the light-shielding film or the combination of the light-shielding film and the antireflection film, the film thickness of the second layer is usually 20 to 100 nm, and preferably 40 to 70 nm. Further, under exposure light having a wavelength of 200 nm or less, the total optical density of the phase shift film and the second layer is preferably 2.0 or more, particularly preferably 2.5 or more, and more preferably 3.0 or more.

[0086] (Processing aid film as the second layer)

[0087] When the second layer is a processing auxiliary film, it can also be used as a processing auxiliary film (etching mask film) that functions as a hard mask in pattern formation of the phase shift film, or as an etching stopper layer in pattern formation of the third layer.

[0088] Examples of the processing assisting film include a film made of a material containing chromium as disclosed in Patent Document 4. The processing assisting film may be composed of a single layer or a plurality of layers.

[0089] Materials containing chromium for the processing auxiliary film include chromium monomer, chromium oxide (CrO), chromium nitride (CrN), chromium carbide (CrC), chromium oxynitride (CrON), chromium oxycarbide (CrOC), chromium nitride carbide (CrNC), chromium oxynitride carbide (CrONC) and other chromium compounds.

[0090] When the second layer is a processing auxiliary film, the Cr content in the Cr compound of the second layer is preferably 40 atomic % or more, particularly preferably 50 atomic % or more, preferably 100 atomic % or less, particularly preferably 99 atomic % or less, and particularly preferably 90 atomic % or less. The oxygen content is preferably 60 atomic % or less, particularly preferably 55 atomic % or less, and when the etching rate needs to be adjusted, it is more preferably 1 atomic % or more. The nitrogen content is preferably 50 atomic % or less, particularly preferably 40 atomic % or less, and more preferably 1 atomic % or more. The carbon content is preferably 20 atomic % or less, particularly preferably 10 atomic % or less, and when the etching rate needs to be adjusted, it is more preferably 1 atomic % or more. At this time, the total content of chromium, oxygen, nitrogen and carbon is preferably 95 atomic % or more, particularly preferably 99 atomic % or more, and particularly preferably 100 atomic %.

[0091] <Third Floor>

[0092] A third layer, consisting of a single layer or multiple layers, may be provided on the second layer of the phase-shift mask blank of the present invention. The third layer is typically provided adjacent to the second layer. Specific examples of this third layer include a processing auxiliary film, a light-shielding film, or a combination of a light-shielding film and an anti-reflection film. The material for the third layer is preferably a material containing silicon, and particularly preferably a material that does not contain chromium.

[0093] Specifically, the phase shift mask blanks include Figure 2 Phase shift mask blank shown. Figure 2 The phase shift mask blank 100 is a cross-sectional view showing an example of the phase shift mask blank of the present invention. The phase shift mask blank 100 includes a transparent substrate 10 , a phase shift film 1 formed on the transparent substrate 10 , a second layer 2 formed on the phase shift film 1 , and a third layer 3 formed on the second layer 2 .

[0094] (As the third layer of processing auxiliary film)

[0095] When the second layer is a light-shielding film, a combination of a light-shielding film and an anti-reflective film, or a processing auxiliary film that functions as a hard mask in patterning the aforementioned halftone phase shift film, a processing auxiliary film (etching mask film) that functions as a hard mask in patterning the second layer can be provided as the third layer. Furthermore, when a fourth layer (described later) is provided, the third layer can also function as a processing auxiliary film (etching stop film) that functions as an etch stop layer in patterning the fourth layer.

[0096] The processing auxiliary film is preferably made of a material having etching properties different from those of the second layer, for example, a material resistant to chlorine-based dry etching suitable for etching materials containing chromium, specifically a material containing silicon that can be etched using fluorine-based gases such as SF6 or CF4.

[0097] Specifically, materials containing silicon include simple silicon; materials containing silicon and one or both of nitrogen and oxygen; materials containing silicon and a transition metal; silicon compounds such as materials containing one or both of nitrogen and oxygen, silicon, and a transition metal. Examples of transition metals include molybdenum, tantalum, zirconium, and the like.

[0098] When the third layer is a processing auxiliary film, the processing auxiliary film is preferably a silicon compound, and the silicon content in the silicon compound is preferably 20 atomic % or more, particularly preferably 33 atomic % or more, preferably 95 atomic % or less, and particularly preferably 80 atomic % or less. The nitrogen content is preferably 50 atomic % or less, particularly preferably 30 atomic % or less, and more preferably 1 atomic % or more. The oxygen content is preferably 70 atomic % or less, particularly preferably 66 atomic % or less. When the etching speed needs to be adjusted, it is more preferably 1 atomic % or more, and further preferably 20 atomic % or more. It may contain a transition metal or may not contain a transition metal. When it contains a transition metal, its content is preferably 35 atomic % or less, and particularly preferably 20 atomic % or less. At this time, the total content of silicon, oxygen, nitrogen and transition metal is preferably 95 atomic % or more, particularly preferably 99 atomic % or more, and particularly preferably 100 atomic %.

[0099] When the second layer is a light-shielding film, or a combination of a light-shielding film and an antireflection film, and the third layer is a processing-assisting film, the second layer typically has a thickness of 20 to 100 nm, preferably 40 to 70 nm, and the third layer typically has a thickness of 1 to 30 nm, preferably 2 to 15 nm. Furthermore, under exposure light having a wavelength of 200 nm or less, the combined optical density of the phase shift film, the second layer, and the third layer is preferably 2.0 or greater, particularly preferably 2.5 or greater, and even more preferably 3.0 or greater.

[0100] On the other hand, when the second layer is a process assist film and the third layer is a process assist film, the film thickness of the second layer is usually 1 to 20 nm, preferably 2 to 10 nm, and the film thickness of the third layer is usually 1 to 20 nm, preferably 2 to 10 nm.

[0101] (Light shielding film and antireflection film as the third layer)

[0102] Further, when the second layer is a process assist film, a light shielding film can be provided as the third layer. Further, a light shielding film and an antireflection film can be provided in combination as the third layer.

[0103] It is preferable that the light shielding film and the antireflection film of the third layer be made of a material having etching characteristics different from those of the second layer, for example, a material resistant to chlorine dry etching suitable for etching of a material containing chromium, and specifically a material containing silicon that can be etched using a fluorine gas such as SF6or CF4.

[0104] As the material containing silicon, specifically, there can be mentioned, for example, silicon simple substance; a material containing one or both of nitrogen and oxygen and silicon; a material containing silicon and a transition metal; a material containing one or both of nitrogen and oxygen, silicon, and a transition metal; and a silicon compound, and as the transition metal, there can be mentioned, for example, molybdenum, tantalum, zirconium, and the like.

[0105] When the third layer is a light shielding film or a combination of a light shielding film and an antireflection film, it is preferable that the light shielding film and the antireflection film be a silicon compound, and the content of silicon in the silicon compound is preferably 10 atomic % or more, particularly preferably 30 atomic % or more, and is preferably less than 100 atomic %, particularly preferably 95 atomic % or less. The content of nitrogen is preferably 50 atomic % or less, particularly preferably 40 atomic % or less, and further preferably 20 atomic % or less, and when it is necessary to adjust the etching rate, it is more preferable to be 1 atomic % or more. The content of oxygen is preferably 60 atomic % or less, particularly preferably 30 atomic % or less, and when it is necessary to adjust the etching rate, it is preferable to be 1 atomic % or more. The content of the transition metal is preferably 35 atomic % or less, particularly preferably 20 atomic % or less, and more preferably 1 atomic % or more. At this time, the total content of silicon, oxygen, nitrogen, and the transition metal is preferably 95 atomic % or more, particularly preferably 99 atomic % or more, and further preferably 100 atomic %.

[0106] When the second layer is a process assist film and the third layer is a light shielding film or a combination of a light shielding film and an antireflection film, the film thickness of the second layer is usually 1 to 20 nm, preferably 2 to 10 nm, and the film thickness of the third layer is usually 20 to 100 nm, preferably 30 to 70 nm. Further, under exposure light having a wavelength of 200 nm or less, the total optical density of the phase shift film and the second layer and the third layer is preferably 2.0 or more, particularly preferably 2.5 or more, and further preferably 3.0 or more.

[0107] <Fourth Layer>

[0108] A fourth layer composed of a single layer or a plurality of layers can be provided on the third layer of the phase shift mask blank of the present application. The fourth layer is generally provided in a manner adjacent to the third layer. As the fourth layer, a processing assist film or the like that functions as a hard mask in the pattern formation of the third layer can be specifically mentioned. As the material of the fourth layer, a material containing chromium is suitable.

[0109] As the phase shift mask blank described above, a phase shift mask blank shown in FIG. 1 can be specifically mentioned. Figure 3 The phase shift mask blank shown in FIG. 1. Figure 3 A cross-sectional view showing one example of the phase shift mask blank of the present application, the phase shift mask blank 100 has a transparent substrate 10, a phase shift film 1 formed on the transparent substrate 10, a second layer 2 formed on the phase shift film 1, a third layer 3 formed on the second layer 2, and a fourth layer 4 formed on the third layer 3.

[0110] (Processing assist film as the fourth layer)

[0111] When the third layer is a light shielding film or a combination of a light shielding film and an antireflection film, as the fourth layer, a processing assist film (etching mask film) that functions as a hard mask in the pattern formation of the third layer can be provided.

[0112] It is preferable to set the processing assist film to a material having etching characteristics different from those of the third layer, for example, a material resistant to fluorine-based dry etching suitable for etching of a material containing silicon, and specifically to a material containing chromium that can be etched using a chlorine-based gas containing oxygen.

[0113] As the material containing chromium, chromium compounds such as elemental chromium, chromium oxide (CrO), chromium nitride (CrN), chromium carbide (CrC), chromium oxynitride (CrON), chromium oxycarbide (CrOC), chromium nitridocarbide (CrNC), and chromium oxynitridocarbide (CrONC) can be specifically mentioned.

[0114] When the fourth layer is a processing assist film, the content of chromium in the fourth layer is preferably 30 atomic% or more, particularly preferably 40 atomic% or more, and is preferably 100 atomic% or less, particularly preferably 99 atomic% or less, and even more preferably 90 atomic% or less. The content of oxygen is preferably 60 atomic% or less, particularly preferably 40 atomic% or less, and is more preferably 1 atomic% or more when it is necessary to adjust the etching rate. The content of nitrogen is preferably 50 atomic% or less, particularly preferably 40 atomic% or less, and is more preferably 1 atomic% or more when it is necessary to adjust the etching rate. The content of carbon is preferably 20 atomic% or less, particularly preferably 10 atomic% or less, and is more preferably 1 atomic% or more when it is necessary to adjust the etching rate. At this time, the total content of chromium, oxygen, nitrogen, and carbon is preferably 95 atomic% or more, particularly preferably 99 atomic% or more, and even more preferably 100 atomic%.

[0115] When the second layer is a process assist film, the third layer is a light shielding film or a combination of a light shielding film and an antireflection film, and the fourth layer is a process assist film, the film thickness of the second layer is usually 1 to 20 nm, preferably 2 to 10 nm, the film thickness of the third layer is usually 20 to 100 nm, preferably 30 to 70 nm, and the film thickness of the fourth layer is usually 1 to 30 nm, preferably 2 to 20 nm. In addition, the total optical density of the phase shift film, the second layer, the third layer, and the fourth layer under exposure light having a wavelength of 200 nm or less is preferably 2.0 or more, particularly preferably 2.5 or more, and even more preferably 3.0 or more.

[0116] <Method for forming second to fourth layers>

[0117] The film of the second layer and the fourth layer composed of a material containing chromium can be formed by reactive sputtering using a chromium target, a target in which any one or two or more selected from the group consisting of oxygen, nitrogen, and carbon is added to chromium, and the like, and using a sputtering gas in which a reactive gas selected from the group consisting of an oxygen-containing gas, a nitrogen-containing gas, a carbon-containing gas, and the like is appropriately added to a rare gas such as Ar, He, Ne, or the like, according to the composition of the film to be formed.

[0118] On the other hand, the film of the third layer composed of a material containing silicon can be formed by reactive sputtering using a silicon target, a silicon nitride target, a target containing both silicon and silicon nitride, a transition metal target, a composite target of silicon and a transition metal, and the like, and using a sputtering gas in which a reactive gas selected from the group consisting of an oxygen-containing gas, a nitrogen-containing gas, a carbon-containing gas, and the like is appropriately added to a rare gas such as Ar, He, Ne, or the like, according to the composition of the film to be formed.

[0119] <Method for manufacturing phase shift mask>

[0120] In addition, the present application provides a method for manufacturing a phase shift mask using the above-described phase shift mask blank. The phase shift mask of the present application can be manufactured from the phase shift mask blank of the present application by a conventional method. Hereinafter, a specific example of the method for manufacturing a phase shift mask of the present application will be shown.

[0121] Example 1

[0122] For a phase shift mask blank in which a film of a material containing chromium is formed on a phase shift film as a second layer, a phase shift mask can be manufactured, for example, by the following procedure.

[0123] First, an electron beam resist film is formed on the second layer of the phase shift mask blank, electron beam-based pattern writing is performed, and then an resist pattern is obtained by a prescribed development operation. Next, the obtained resist pattern is used as an etching mask, a chlorine-based dry etching containing oxygen is performed to transfer the resist pattern to the second layer, and a pattern of the second layer is obtained. Next, the obtained pattern of the second layer is used as an etching mask, a fluorine-based dry etching is performed to transfer the pattern of the second layer to the upper layer of the phase shift film, and a phase shift film pattern is obtained. Then, the second layer and the lower layer of the phase shift film exposed thereby are removed by a chlorine-based dry etching containing oxygen, and a phase shift mask is obtained. Here, when a part of the second layer is to be left, a resist pattern for protecting the part is formed on the second layer, and then a chlorine-based dry etching containing oxygen is performed to remove the second layer of the part not protected by the resist pattern and the lower layer of the phase shift film exposed thereby. Then, the resist pattern is removed by a conventional method, and a phase shift mask is obtained.

[0124] Example 2

[0125] Further, for a phase shift mask blank in which a light shielding film containing a material including chromium, or a combination of a light shielding film and an antireflection film is formed on a phase shift film as a second layer, and a processing aid film containing a material including silicon is formed on the second layer as a third layer, a phase shift mask can be manufactured, for example, by the following procedure.

[0126] First, an electron beam resist film is formed on the third layer of the phase shift mask blank, electron beam-based pattern writing is performed, and then a resist pattern is obtained by a prescribed development operation. Next, the obtained resist pattern is used as an etching mask, a fluorine-based dry etching is performed to transfer the resist pattern to the third layer, and a pattern of the third layer is obtained. Next, the obtained pattern of the third layer is used as an etching mask, a chlorine-based dry etching containing oxygen is performed to transfer the pattern of the third layer to the second layer, and a pattern of the second layer is obtained. Next, the resist pattern is removed, and then the obtained pattern of the second layer is used as an etching mask, a fluorine-based dry etching is performed to transfer the pattern of the second layer to the upper layer of the phase shift film, and a phase shift film pattern is obtained while the pattern of the third layer is removed. Next, a resist pattern for protecting a part of the second layer to be left is formed on the second layer, and then a chlorine-based dry etching containing oxygen is performed to remove the second layer of the part not protected by the resist pattern and the lower layer of the phase shift film exposed thereby. Then, the resist pattern is removed by a conventional method, and a phase shift mask is obtained.

[0127] Example 3

[0128] On the other hand, for a phase shift mask blank in which a processing aid film containing a material including chromium is formed on a phase shift film as a second layer, and a light shielding film containing a material including silicon, or a combination of a light shielding film and an antireflection film is formed on the second layer as a third layer, a phase shift mask can be manufactured, for example, by the following procedure.

[0129] First, an electron beam resist film is formed on the third layer of the phase shift mask blank, and electron beam-based pattern writing is performed, and then an resist pattern is obtained by a prescribed development operation. Next, the obtained resist pattern is used as an etching mask, and a fluorine-based dry etching is performed to transfer the resist pattern to the third layer, and a pattern of the third layer is obtained. Next, the obtained pattern of the third layer is used as an etching mask, and a chlorine-based dry etching containing oxygen is performed to transfer the pattern of the third layer to the second layer, and a pattern of the second layer in which the portion of the second layer to be removed of the phase shift film is removed is obtained. Next, the resist pattern is removed, and a resist pattern which protects the portion of the third layer to be left is formed on the third layer, and then the obtained pattern of the second layer is used as an etching mask, and a fluorine-based dry etching is performed to transfer the pattern of the second layer to the upper layer of the phase shift film, and a phase shift film pattern is obtained, and the third layer of the portion not protected by the resist pattern is removed. Next, the resist pattern is removed by a conventional method. Then, the second layer of the portion of the third layer which has been removed, and the lower layer of the phase shift film which has been exposed are removed by a chlorine-based dry etching containing oxygen, and a phase shift mask is obtained.

[0130] Example 4

[0131] Further, for example, a phase shift mask blank in which a processing assist film containing a material of chromium is formed on a phase shift film as a second layer, a light shielding film containing a material of silicon, or a combination of a light shielding film and an antireflection film is formed on the second layer as a third layer, and a processing assist film containing a material of chromium is further formed on the third layer as a fourth layer can be manufactured by the following procedure.

[0132] First, an electron beam resist film is formed on the fourth layer of the phase shift mask blank, and electron beam-based pattern writing is performed, and then an resist pattern is obtained by a prescribed development operation. Next, the obtained resist pattern is used as an etching mask, and a chlorine-based dry etching containing oxygen is performed to transfer the resist pattern to the fourth layer, and a pattern of the fourth layer is obtained. Next, the obtained pattern of the fourth layer is used as an etching mask, and a fluorine-based dry etching is performed to transfer the pattern of the fourth layer to the third layer, and a pattern of the third layer is obtained. Next, the resist pattern is removed, and a resist pattern which protects the portion of the third layer to be left is formed on the fourth layer, and the obtained pattern of the third layer is used as an etching mask, and a chlorine-based dry etching containing oxygen is performed to transfer the pattern of the third layer to the second layer, and a pattern of the second layer is obtained, and the fourth layer of the portion not protected by the resist pattern is removed. Next, the pattern of the second layer is used as an etching mask, and a fluorine-based dry etching is performed to transfer the pattern of the second layer to the upper layer of the phase shift film, and a phase shift film pattern is obtained, and the third layer of the portion not protected by the resist pattern is removed. Next, the resist pattern is removed by a conventional method. Then, the second layer of the portion of the third layer which has been removed, the fourth layer of the portion of the resist pattern which has been removed, and the lower layer of the phase shift film which has been exposed are removed by a chlorine-based dry etching containing oxygen, and a phase shift mask is obtained.

[0133] <Phase shift mask>

[0134] Further, the present application provides a phase shift mask. The phase shift mask of the present application has a transparent substrate and a phase shift film having a pattern formed on the transparent substrate, and the transparent substrate and the phase shift film are as described above. Further, it can also be a phase shift mask provided with a light shielding film containing chromium on the phase shift film.

[0135] The phase shift mask of the present application is particularly effective in exposure using an ArF excimer laser (wavelength 193 nm), F2 laser (wavelength 157 nm), or the like, in which the wavelength of the exposure light is 250 nm or less, particularly 200 nm or less, for transferring a pattern to a photoresist film formed on a substrate to be processed in photolithography for forming a pattern having a half pitch of 50 nm or less, particularly 30 nm or less, and even more particularly 20 nm or less.

[0136] Example

[0137] Hereinafter, the present application will be specifically described using examples and comparative examples, but the present application is not limited thereto.

[0138] [Example 1]

[0139] A 152 mm square, 6.35 mm thick 6025 quartz substrate was set in the chamber of a sputtering device, a chromium target and a silicon target were used as sputtering targets, and argon, nitrogen, and oxygen were used as sputtering gases to form a layer of CrSiON at a film thickness of 5 nm. Next, the substrate on which the CrSiON was formed was set in the chamber of another sputtering device, a MoSi target and a silicon target were used as sputtering targets, and argon, nitrogen, and oxygen were used as sputtering gases to form a layer of MoSiON at a film thickness of 71 nm. The phase difference and the transmittance of the two layers of CrSiON and MoSiON were measured, and the results were a phase difference of 180 deg and a transmittance of 6.0%.

[0140] Next, the composition of each layer was measured by XPS, and the results were that in the CrSiON layer, chromium was 41%, silicon was 2%, nitrogen was 13%, and oxygen was 44%, and in the MoSiON layer, molybdenum was 7%, silicon was 38%, nitrogen was 40%, and oxygen was 15%. That is, the content ratio of silicon in the lower layer was 5% relative to the total of chromium and silicon, and the content ratio of oxygen was 1.0 relative to the total content ratio of chromium and silicon.

[0141] Next, a light shielding film of CrON was formed on the phase shift film formed of the two layers of CrSiON and MoSiON in the sputtering device at a film thickness of 48 nm in a manner such that the OD under exposure light of 193 nm was 3 or more.

[0142] Next, the etching rate of each layer was calculated and the selectivity of each layer was confirmed by performing etching using Cl and F on each layer of the photomask blank obtained in the dry etching apparatus. The selectivity of F dry etching of the CrSiON layer and the MoSiON layer on the quartz substrate was 30, and the selectivity of Cl dry etching of the CrSiON layer and the CrON light shielding layer was 3.5.

[0143] Figure 4 The outline of the dry etching apparatus used is shown in FIG. 10. The dry etching apparatus 1000 is composed of a chamber 101, a ground wire 102, a lower electrode 103 on which a substrate to be processed 105 is placed, an antenna coil 104, high frequency power sources RF1, RF2.

[0144] Next, using the obtained photomask blank, a resist was applied and pattern writing was performed, and a photomask having a line / space pattern of 200 nm line width was obtained by a resist peeling and fluorine or Cl dry etching process of each layer. The obtained pattern portion was cut, and the cross-sectional shape of the pattern portion was observed and confirmed using a scanning microscope, and as a result, the side etching amount of the CrSiON layer on the quartz substrate was small, and a good shape was maintained.

[0145] <Fluorine dry etching conditions>

[0146] RF1 (RIE: reactive ion etching): CW (continuous discharge) 54 W

[0147] RF2 (ICP: inductively coupled plasma): CW (continuous discharge) 325 W

[0148] Pressure: 5 mTorr

[0149] SF6: 18 seem

[0150] O2: 45 seem

[0151] <Cl dry etching conditions>

[0152] RF1 (RIE: reactive ion etching): CW (continuous discharge) 700 V

[0153] RF2 (ICP: inductively coupled plasma): CW (continuous discharge) 400 W

[0154] Pressure: 6 mTorr

[0155] Cl2: 185 seem

[0156] O2: 55 seem

[0157] He: 9.25 seem

[0158] [Example 2]

[0159] A 152 mm square, 6.35 mm thick 6025 quartz substrate was set in the chamber of a sputtering device, and a layer formed of CrSiON was deposited in a film thickness of 5 nm in the same manner as in Example 1, except that the power applied to the Cr target and the Si target was changed. Subsequently, a layer formed of MoSiON was deposited in a film thickness of 70 nm in the same manner as in Example 1. The phase difference and the transmittance of the two layers formed of CrSiON and MoSiON were measured, and as a result, the phase difference was 180 deg, and the transmittance was 6.0%.

[0160] Subsequently, the composition of each layer was measured by XPS, and as a result, in the CrSiON layer, chromium was 42.5%, silicon was 1.5%, nitrogen was 14%, and oxygen was 42%, and in the MoSiON layer, Mo was 7%, Si was 38%, nitrogen was 40%, and oxygen was 15%. That is, the content ratio of silicon in the lower layer was 3% relative to the total of chromium and silicon, and the content ratio of oxygen was 1.0 relative to the total content ratio of chromium and silicon.

[0161] Subsequently, in the sputtering device, a light-shielding film formed of CrON was deposited on the phase shift film formed of the two layers of CrSiON layer and MoSiON layer in a film thickness of 48 nm in such a manner that the OD under exposure light of 193 nm was 3 or more.

[0162] Subsequently, each layer of the photomask blank obtained in the dry etching device was subjected to etching using Cl and etching using F, the etching rate of each layer was calculated, and the selectivity of each layer was confirmed. The selectivity of F dry etching of the CrSiON layer and the MoSiON layer on the quartz substrate was 32, and the selectivity of Cl dry etching of the CrSiON layer and the CrON light-shielding layer was 2.0.

[0163] A line / space pattern with a line width of 200 nm was produced in the same manner as in Example 1, and the cross-sectional shape of the pattern portion was confirmed, and as a result, the pattern portion was good.

[0164] [Example 3]

[0165] A 152 mm square, 6.35 mm thick 6025 quartz substrate was set in the chamber of a sputtering device, and a layer formed of CrSiON was deposited in a film thickness of 5 nm in the same manner as in Example 1. Subsequently, a Si target was installed in the chamber of the sputtering device, and a layer formed of SiN was deposited in a film thickness of 63 nm using argon and nitrogen as sputtering gas. The phase difference and the transmittance of the two layers formed of CrSiON and SiN were measured, and as a result, the phase difference was 180 deg, and the transmittance was 6.0%.

[0166] Next, the composition of each layer was measured by XPS, and as a result, in the CrSiON layer, chromium was 42.5%, silicon was 1.5%, nitrogen was 14%, and oxygen was 42%, and in the SiN layer, silicon was 45%, and nitrogen was 55%. That is, the content ratio of silicon in the lower layer was 3% relative to the total of chromium and silicon, and the content ratio of oxygen was 1.0 relative to the total content ratio of chromium and silicon.

[0167] Next, in the sputtering device, a light-blocking film formed of CrON was formed on the phase shift film formed of the two layers of the CrSiON layer and the SiN layer, at a film thickness of 48 nm in a manner such that the OD under exposure light of 193 nm was 3 or more.

[0168] Next, each layer of the photomask blank obtained in the dry etching device was subjected to etching using Cl and etching using F, the etching rate of each layer was calculated, and the selectivity of each layer was confirmed. The selectivity of F dry etching of the CrSiON layer and the SiN layer on the quartz substrate was 12, and the selectivity of Cl dry etching of the CrSiON layer and the CrON light-blocking layer was 2.0.

[0169] A line / space pattern with a line width of 200 nm was produced in the same manner as in Example 1, and the cross-sectional shape of the pattern portion was confirmed, and as a result, the pattern portion was good.

[0170] [Example 4]

[0171] A 6025 quartz substrate with an area of 152 mm square and a thickness of 6.35 mm was disposed in the chamber of a sputtering device, and a layer formed of CrSiON was formed at a film thickness of 5 nm in the same manner as in Example 1, except that a chromium target was used. Next, a layer formed of MoSiON was formed at a film thickness of 73 nm in the same manner as in Example 1. The phase difference and the transmittance of the two layers formed of CrSiON and MoSiON were measured, and as a result, the phase difference was 180 deg, and the transmittance was 6.0%.

[0172] Next, the composition of each layer was measured by XPS, and as a result, in the CrSiON layer, chromium was 35.5%, silicon was 5.5%, nitrogen was 10%, and oxygen was 49%, and in the MoSiON layer, Mo was 7%, Si was 38%, nitrogen was 40%, and oxygen was 15%. That is, the content ratio of silicon in the lower layer was 13% relative to the total of chromium and silicon, and the content ratio of oxygen was 1.2 relative to the total content ratio of chromium and silicon.

[0173] Next, in the sputtering device, a light-blocking film formed of CrON was formed on the phase shift film formed of the two layers of the CrSiON layer and the MoSiON layer, at a film thickness of 48 nm in a manner such that the OD under exposure light of 193 nm was 3 or more.

[0174] Next, the respective layers of the photomask blank obtained in the dry etching apparatus were subjected to etching using Cl-based etching and etching using F-based etching, the etching rates of the respective layers were calculated, and the selectivity of the respective layers was confirmed. The selectivity of F-based dry etching of the CrSiON layer and the MoSiON layer on the quartz substrate was 28, and the selectivity of Cl-based dry etching of the CrSiON layer and the CrON light-shielding layer was 10.

[0175] A line / space pattern with a line width of 200 nm was produced in the same manner as in Example 1, and the cross-sectional shape of the pattern portion was confirmed, as a result of which the pattern portion was good.

[0176] [Example 5]

[0177] A 152 mm square, 6.35 mm thick 6025 quartz substrate was set in the chamber of the sputtering apparatus, and a layer formed of CrSiON was formed in a film thickness of 5 nm in the same manner as in Example 1, except that a chromium target was used. Next, a layer formed of MoSiON was formed in a film thickness of 73 nm in the same manner as in Example 1. The phase difference and the transmittance of the two layers formed of CrSiON and MoSiON were measured, as a result of which the phase difference was 180 deg, and the transmittance was 6.0%.

[0178] Next, the composition of the respective layers was measured by XPS, as a result of which in the CrSiON layer, chromium was 36%, silicon was 3%, nitrogen was 2%, and oxygen was 59%, and in the MoSiON layer, Mo was 7%, Si was 38%, nitrogen was 40%, and oxygen was 15%. That is, the content ratio of silicon in the lower layer with respect to the total of chromium and silicon was 8%, and the content ratio of oxygen with respect to the total content ratio of chromium and silicon was 1.5.

[0179] Next, a light-shielding film formed of CrON was formed in a film thickness of 48 nm on the phase shift film formed of the two layers of the CrSiON layer and the MoSiON layer in such a manner that the OD under exposure light of 193 nm was 3 or more.

[0180] Next, the respective layers of the photomask blank obtained in the dry etching apparatus were subjected to etching using Cl-based etching and etching using F-based etching, the etching rates of the respective layers were calculated, and the selectivity of the respective layers was confirmed. The selectivity of F-based dry etching of the CrSiON layer and the MoSiON layer on the quartz substrate was 10, and the selectivity of Cl-based dry etching of the CrSiON layer and the CrON light-shielding layer was 5.

[0181] A line / space pattern with a line width of 200 nm was produced in the same manner as in Example 1, and the cross-sectional shape of the pattern portion was confirmed, as a result of which the pattern portion was good. The selectivity of F-based etching of this film was 10, and if more oxygen is added, the resistance to F-based etching is too low, and the function as sputtering decreases.

[0182] [Comparative Example 1]

[0183] A 152 mm square, 6.35 mm thick 6025 quartz substrate was set in the chamber of a sputtering device, and a layer formed of CrON was formed in a film thickness of 5 nm in the same manner as in Example 1, except that a chromium target was used. Next, a layer formed of MoSiON was formed in a film thickness of 73 nm in the same manner as in Example 1. The phase difference and transmittance of the two layers formed of CrON and MoSiON were measured, and as a result, the phase difference was 180 deg, and the transmittance was 6.0%.

[0184] Next, the composition of each layer was measured by XPS, and as a result, in the CrON layer, chromium was 43%, nitrogen was 14.5%, and oxygen was 42.5%, and in the MoSiON layer, Mo was 7%, Si was 38%, nitrogen was 40%, and oxygen was 15%. That is, the content ratio of silicon in the lower layer with respect to the total of chromium and silicon was 0%, and the content ratio of oxygen with respect to the total content ratio of chromium and silicon was 1.0.

[0185] Next, in the sputtering device, a light-shielding film formed of CrON was formed on the phase shift film formed of the two layers of the CrON layer and the MoSiON layer in a film thickness of 48 nm in such a manner that the OD under exposure light of 193 nm was 3 or more.

[0186] Next, each layer of the photomask blank obtained in the dry etching device was subjected to etching using Cl and etching using F, the etching rate of each layer was calculated, and the selectivity of each layer was confirmed. The selectivity of F dry etching of the CrON layer and the MoSiON layer on the quartz substrate was 33, and the selectivity of Cl dry etching of the CrON layer and the CrON light-shielding layer was 1.0.

[0187] A line / space pattern with a line width of 200 nm was produced in the same manner as in Example 1, and the cross-sectional shape of the pattern portion was confirmed, and as a result, the pattern portion of the CrON layer on the quartz substrate was side-etched, and the cross-sectional shape was not good. This was a result of the lower layer of the phase shift film not containing silicon, and the etching rate of the lower layer using Cl being too high.

[0188] [Comparative Example 2]

[0189] A 152 mm square, 6.35 mm thick 6025 quartz substrate was set in the chamber of a sputtering device, and a layer formed of CrSiON was formed in a film thickness of 5 nm in the same manner as in Example 1, except that the oxygen flow rate introduced into the chamber was increased. Subsequently, a layer formed of MoSiON was formed in a film thickness of 69 nm in the same manner as in Example 1. The phase difference and transmittance of the two layers formed of CrSiON and MoSiON were measured, and as a result, the phase difference was 180 deg, and the transmittance was 6.0%.

[0190] Subsequently, the composition of each layer was measured by XPS, and as a result, in the CrSiON layer, chromium was 33%, silicon was 4%, nitrogen was 1%, and oxygen was 62%, and in the MoSiON layer, molybdenum was 7%, silicon was 38%, nitrogen was 40%, and oxygen was 15%. That is, the content ratio of silicon in the lower layer with respect to the total of chromium and silicon was 11%, and the content ratio of oxygen with respect to the total content ratio of chromium and silicon was 1.7.

[0191] Subsequently, in the sputtering device, a light-shielding film formed of CrON was formed on the phase shift film formed of the two layers of the CrSiON layer and the MoSiON layer in a film thickness of 48 nm in such a manner that the OD under exposure light of 193 nm was 3 or more.

[0192] Subsequently, each layer of the photomask blank obtained in the dry etching device was subjected to etching using Cl-based etching and etching using F-based etching, the etching rate of each layer was calculated, and the selectivity of each layer was confirmed. The selectivity of F-based dry etching of the CrSiON layer and the MoSiON layer on the quartz substrate was 0.5 or less, and the selectivity of Cl-based dry etching of the CrSiON layer and the CrON light-shielding layer was 3.0.

[0193] A line / space pattern with a line width of 200 nm was produced in the same manner as in Example 1, and the cross-sectional shape of the pattern portion was confirmed, and as a result, a groove was generated on the quartz substrate. In the CrSiON film (lower layer) having a high oxygen content, the etching rate using F-based etching was too fast, and etching proceeded to the quartz portion.

[0194] [Comparative Example 3]

[0195] A 152 mm square, 6.35 mm thick 6025 quartz substrate was set in the chamber of a sputtering device, and a layer formed of CrSiON was formed in a film thickness of 5 nm in the same manner as in Example 1, except that the power applied to the Cr target and the Si target. Subsequently, a layer formed of MoSiON was formed in a film thickness of 69 nm in the same manner as in Example 1. The phase difference and transmittance of the two layers formed of CrSiON and MoSiON were measured, and as a result, the phase difference was 180 deg, and the transmittance was 6.0%.

[0196] Next, the composition of each layer was measured by XPS, and the results were that in the CrSiON layer, chromium was 32%, silicon was 7%, nitrogen was 4%, and oxygen was 57%, and in the MoSiON layer, molybdenum was 7%, silicon was 38%, nitrogen was 40%, and oxygen was 15%. That is, the content ratio of silicon in the lower layer relative to the total of chromium and silicon was 18%, and the content ratio of oxygen relative to the total content ratio of chromium and silicon was 1.5.

[0197] Next, a light-blocking film formed of CrON was formed on the phase shift film formed of the two layers of CrSiON layer and MoSiON layer in the sputtering device in such a manner that the OD under exposure light of 193 nm was 3 or more, and the film thickness was 48 nm.

[0198] Next, each layer of the photomask blank obtained in the dry etching device was subjected to etching using Cl and etching using F, the etching rate of each layer was calculated, and the selectivity of each layer was confirmed. The selectivity of F dry etching of the CrSiON layer and the MoSiON layer on the quartz substrate was 12, and for Cl dry etching of the CrSiON layer and the CrON light-blocking layer, the CrSiON film (lower layer) with a high content of Si could not be peeled off by chlorine etching, and thus the selectivity could not be calculated.

[0199] In addition, the present application is not limited to the above-described embodiments. The above-described embodiments are examples, and technical solutions having substantially the same configuration as the technical concept described in the claims of the present application and exerting the same effects are included in the technical scope of the present application.

Claims

1. A phase shift mask blank comprising a transparent substrate and a phase shift film formed on the transparent substrate, wherein: The phase shift film has a phase difference of 160 to 200° and a transmittance of 3 to 15% at an exposure wavelength of less than 200 nm. The phase shift film includes a lower layer and an upper layer in order from the transparent substrate side. The upper layer contains a transition metal and silicon, and contains nitrogen and / or oxygen, or the upper layer contains silicon, and contains nitrogen and / or oxygen, The lower layer contains chromium and silicon, and contains nitrogen and / or oxygen, the silicon content is 3% or more and less than 15% relative to the total of chromium and silicon in the lower layer, and the ratio of the oxygen content to the total of chromium and silicon is less than 1.7, and The etching selectivity ratio between the upper layer and the lower layer in fluorine-based dry etching is 10 or more.

2. The phase shift mask blank according to claim 1, wherein: The transparent substrate is formed of quartz.

3. The phase shift mask blank according to claim 1, wherein: The thickness of the lower layer is 2 to 10 nm, and the thickness of the upper layer is 50 to 80 nm.

4. The phase-shift mask blank according to claim 2, wherein: The thickness of the lower layer is 2 to 10 nm, and the thickness of the upper layer is 50 to 80 nm.

5. The phase-shift mask blank according to claim 1, wherein: In the upper layer, the transition metal is molybdenum (Mo), and the content of molybdenum (Mo) is 20% or less relative to the total of silicon (Si) and molybdenum (Mo).

6. The phase-shift mask blank according to claim 2, wherein: In the upper layer, the transition metal is molybdenum (Mo), and the content of molybdenum (Mo) is 20% or less relative to the total of silicon (Si) and molybdenum (Mo).

7. The phase-shift mask blank according to claim 3, wherein: In the upper layer, the transition metal is molybdenum (Mo), and the content of molybdenum (Mo) is 20% or less relative to the total of silicon (Si) and molybdenum (Mo).

8. The phase-shift mask blank according to claim 4, wherein: In the upper layer, the transition metal is molybdenum (Mo), and the content of molybdenum (Mo) is 20% or less relative to the total of silicon (Si) and molybdenum (Mo).

9. The phase shift mask blank according to any one of claims 1 to 8, characterized in that: The phase shift mask blank includes a light shielding film containing chromium on the phase shift film, and an etching selectivity ratio between the light shielding film and the underlying layer in chlorine-based dry etching is 1.2 to 10.

0.

10. The phase-shift mask blank according to claim 9, wherein: The phase shift mask blank further includes a hard mask film made of silicon and containing oxygen and / or nitrogen on the light shielding film.

11. A method for manufacturing a phase-shift mask, characterized in that: A phase shift mask is manufactured using the phase shift mask blank according to any one of claims 1 to 10.

12. A phase shift mask comprising a transparent substrate and a phase shift film having a pattern formed on the transparent substrate, wherein: The phase shift film has a phase difference of 160 to 200° and a transmittance of 3 to 15% at an exposure wavelength of less than 200 nm. The phase shift film includes a lower layer and an upper layer in order from the transparent substrate side. The upper layer contains a transition metal and silicon, and contains nitrogen and / or oxygen, or the upper layer contains silicon, and contains nitrogen and / or oxygen, The lower layer contains chromium and silicon, and contains nitrogen and / or oxygen, the silicon content is 3% or more and less than 15% relative to the total of chromium and silicon in the lower layer, and the ratio of the oxygen content to the total of chromium and silicon is less than 1.7, and The etching selectivity ratio between the upper layer and the lower layer in fluorine-based dry etching is 10 or more.

13. The phase-shift mask according to claim 12, wherein: The transparent substrate is formed of quartz.

14. The phase-shift mask according to claim 12, wherein: The thickness of the lower layer is 2 to 10 nm, and the thickness of the upper layer is 50 to 80 nm.

15. The phase-shift mask according to claim 13, wherein The thickness of the lower layer is 2 to 10 nm, and the thickness of the upper layer is 50 to 80 nm.

16. The phase-shift mask according to claim 12, wherein: In the upper layer, the transition metal is molybdenum (Mo), and the content of molybdenum (Mo) is 20% or less relative to the total of silicon (Si) and molybdenum (Mo).

17. The phase-shift mask according to claim 13, wherein: In the upper layer, the transition metal is molybdenum (Mo), and the content of molybdenum (Mo) is 20% or less relative to the total of silicon (Si) and molybdenum (Mo).

18. The phase-shift mask according to claim 14, wherein: In the upper layer, the transition metal is molybdenum (Mo), and the content of molybdenum (Mo) is 20% or less relative to the total of silicon (Si) and molybdenum (Mo).

19. The phase-shift mask according to claim 15, wherein: In the upper layer, the transition metal is molybdenum (Mo), and the content of molybdenum (Mo) is 20% or less relative to the total of silicon (Si) and molybdenum (Mo).

20. The phase-shift mask according to any one of claims 12 to 19, wherein: The phase shift mask includes a light shielding film containing chromium on the phase shift film, and an etching selectivity ratio between the light shielding film and the underlying layer in chlorine-based dry etching is 1.2 to 10.0.

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