JP2005156700A - Phase shift mask blank, phase shift mask, method for manufacturing phase shift mask blank, and method for transferring pattern - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a phase shift mask blank having little warpage, excellent chemical resistance and sufficient for practical use in relation to optical characteristics (transmittance, phase difference, reflectance, refractive index or the like) which can not be specified in a single layer film because of problems of film stress or chemical resistance. <P>SOLUTION: The phase shift mask blank has a phase shift multilayer film on a substrate. The phase shift multilayer film has a low stress layer comprising a compound containing metal and silicon and having ≤400 MPa film stress, and a chemical-resistant layer comprising a compound containing metal and silicon. The chemical-resistant layer is disposed in adjacent to the low stress layer so as to constitute the outermost surface layer of the phase shift multilayer film, and shows such property that when the layer is immersed in an APM (ammonia/hydrogen peroxide/water mixture) prepared by mixing 30 mass% aqueous ammonia, 30 mass% hydrogen peroxide aqueous solution and water by 1:1:8 volume ratio for one hour at 23°C, reduction in the film thickness is ≤1.0 nm. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a phase shift mask blank, a phase shift mask, a method for manufacturing a phase shift mask blank, and a pattern transfer method used for manufacturing a semiconductor integrated circuit and the like, in particular, a halftone phase shift mask for attenuating exposure light. The present invention relates to a phase shift mask blank used as a material thereof, a manufacturing method thereof, and a pattern transfer method.

  Photomasks used in a wide range of applications including the manufacture of semiconductor integrated circuits such as ICs, LSIs and VLSIs are basically photomasks having a light-shielding film containing chromium as a main component on a translucent substrate. A predetermined pattern is formed on the light shielding film of the blank by applying a photolithographic method and using ultraviolet rays or electron beams. In recent years, along with market demands such as higher integration of semiconductor integrated circuits, pattern miniaturization has progressed rapidly, and this has been dealt with by shortening the exposure wavelength.

  However, while shortening the exposure wavelength improves the resolution, there is a problem in that the depth of focus is reduced, process stability is lowered, and product yield is adversely affected. There is a phase shift method as an effective pattern transfer method for such a problem, and a phase shift mask is used as a mask for transferring a fine pattern.

  This phase shift mask (halftone type phase shift mask) is, for example, on a phase shift mask in which a phase shift film 2 ′ is formed on a substrate 1, as shown in FIGS. The phase shifter portion 2a forming the pattern portion and the substrate exposed portion 1a where the substrate where the phase shifter portion 2a does not exist is exposed, and the phase difference of light transmitted through both is set to about 180 °. Thus, due to the interference of light at the pattern boundary portion, the light intensity becomes zero at the interfered portion, and the contrast of the transferred image can be improved. In addition, by using the phase shift method, it becomes possible to increase the depth of focus for obtaining the required resolution, compared with the case of using a normal mask having a general light-shielding pattern made of a chromium film or the like. It is possible to improve the resolution and the margin of the exposure process.

  The phase shift mask can be roughly divided into a practically transmissive phase shift mask and a halftone phase shift mask depending on the light transmission characteristics of the phase shifter. The complete transmission type phase shift mask is a mask that has a light transmittance of the phase shifter portion equivalent to that of the substrate exposed portion and is transparent at the exposure wavelength. In the halftone phase shift mask, the light transmittance of the phase shifter portion is about several percent to several tens percent of the substrate exposed portion.

  FIG. 11 shows the basic structure of the halftone phase shift mask blank, and FIG. 12 shows the basic structure of the halftone phase shift mask. The halftone phase shift mask blank of FIG. 11 is obtained by forming a halftone phase shift film 2 ′ on almost the entire surface of the substrate 1. Further, the halftone phase shift mask of FIG. 12 is obtained by patterning the phase shift film 2 ′, and includes a phase shifter portion 2 a that forms a pattern portion on the substrate 1 and a substrate exposed portion 1 a that does not have a phase shifter. Become. Here, the phase of the light transmitted through the phase shifter 2a is shifted relative to the light transmitted through the substrate exposed portion 1a, but the transmittance of the phase shifter 2a is not sensitive to the resist on the transfer substrate. Set to light intensity. Therefore, it has a light shielding function that substantially blocks exposure light.

  As the halftone phase shift mask, there is a single-layer halftone phase shift mask that has a simple structure and is easy to manufacture. As this single layer type halftone phase shift mask, a mask having a phase shift film made of a MoSi-based material such as MoSiO, MoSiON or the like has been proposed (for example, Patent Document 1: Japanese Patent Laid-Open No. 7-140635). See the official gazette).

  As described above, the halftone phase shift mask is effective for easily obtaining high resolution. However, if the exposure wavelength is shortened for higher resolution, the exposure apparatus itself has a shallower depth of focus, so an exposure apparatus with a shallower depth of focus will be used. It is important to be flat. Therefore, the quartz substrate is polished until it becomes sufficiently flat and used as a phase shift mask. However, when a large stress is applied to the phase shift film provided on the substrate, warping occurs, and a phase shift mask with sufficient flatness is produced. It can no longer be obtained. Therefore, in order to avoid this problem, it is necessary to sufficiently reduce the stress of the phase shift film itself.

  In addition to this, in the phase shift film used in the halftone phase shift mask, while satisfying optical characteristics such as transmittance, phase difference, reflectance, and refractive index at the used exposure wavelength, It is necessary to satisfy physical properties such as durability and low defects.

  However, in the single-layer halftone phase shift film as described above, when the optical characteristics are set to desired values, the film composition is uniquely determined, and chemical resistance and stress are determined by the film composition. It has been difficult to obtain an excellent phase shift film having both characteristics, low film stress, and chemical resistance.

JP-A-7-140635

  The present invention has been made to solve the above-described problems, and is a phase shift mask blank, a phase shift mask, a method of manufacturing a phase shift mask blank, and a phase shift mask that are excellent in optical characteristics and chemical resistance and have low warpage. An object of the present invention is to provide a pattern transfer method using the above.

  As a result of intensive studies to solve the above problems, the present inventor has, as a result, a low stress layer comprising a compound containing metal and silicon on the substrate and having a film stress of 400 MPa or less, and a compound containing metal and silicon. The amount of decrease in film thickness when immersed in ammonia perwater for 1 hour at 23 ° C. in which 30% by mass aqueous ammonia, 30% by mass hydrogen peroxide and water are mixed at a volume ratio of 1: 1: 8 A phase shift mask blank comprising a phase shift multilayer film having a chemical resistance layer provided adjacent to the low stress layer so as to form an outermost layer of the phase shift multilayer film is 1.0 nm or less, Even when optical properties are set in the region of optical properties (transmittance, phase difference, reflectance, refractive index, etc.) that could not be set due to problems with film stress and chemical resistance in a single layer film, warping Small and medicine It was found to be the ones that resistance was also excellent.

  In particular, the phase shift multilayer film is made of a compound containing metal and silicon, and an optical adjustment layer is provided adjacent to the low-stress layer. The present inventors have found that a phase shift mask blank and a phase shift mask applicable to a wider optical characteristic region can be obtained while sufficiently maintaining the functions of the layer and the low stress layer.

That is, the present invention provides the following phase shift mask blank, phase shift mask, phase shift mask blank manufacturing method, and pattern transfer method.
Claim 1:
A phase shift mask blank comprising a phase shift multilayer film on a substrate, wherein the phase shift multilayer film is made of a compound containing metal and silicon, and a film stress is 400 MPa or less, a metal and silicon The film thickness of the film when immersed in ammonia perwater for 1 hour at 23 ° C. in a mixture of 30% by mass ammonia water, 30% by mass hydrogen peroxide solution and water at a volume ratio of 1: 1: 8. A phase shift mask blank having a chemical resistance layer provided adjacent to the low-stress layer so that the amount of reduction is 1.0 nm or less and forms the outermost layer of the phase shift multilayer film.
Claim 2:
The phase shift mask blank according to claim 1, wherein the phase shift multilayer film further comprises an optical adjustment layer made of a compound containing metal and silicon and provided adjacent to the low stress layer.
Claim 3:
3. The phase shift mask blank according to claim 2, wherein the metal content of the optical adjustment layer is the highest among the low stress layer, the chemical resistance layer and the optical adjustment layer constituting the phase shift multilayer film.
Claim 4:
The phase shift mask blank according to any one of claims 1 to 3, wherein the compound containing metal and silicon is a compound containing metal, silicon, and oxygen and / or nitrogen.
Claim 5:
The phase shift mask blank according to any one of claims 1 to 4, wherein the metal contains at least one selected from molybdenum and zirconium.
Claim 6:
The phase shift mask blank according to any one of claims 1 to 5, further comprising a chromium-based light-shielding film and / or a chromium-based antireflection film on the phase-shift multilayer film.
Claim 7:
A phase shift mask comprising a phase shift multilayer film of the phase shift mask blank according to claim 1 formed as a pattern.
Claim 8:
The method of manufacturing a phase shift mask blank according to any one of claims 1 to 6, wherein the phase shift multilayer film is made of a metal target, a silicon target, and a metal selected from a target made of metal and silicon, and silicon. A method for producing a phase shift mask blank, comprising forming a film on a transparent substrate by sputtering using two or more types of targets having different composition ratios.
Claim 9:
A pattern transfer method comprising performing pattern exposure on a photoresist using the phase shift mask according to claim 7.

  The phase shift mask blank of the present invention has low warpage and excellent chemical resistance, and optical characteristics (transmittance, level, etc.) that cannot be set due to film stress and chemical resistance problems in a single layer film. The phase difference, reflectance, refractive index, etc.) are also practically usable.

The present invention will be described in detail below.
The phase shift mask blank of the present invention is a phase shift mask blank provided with a phase shift multilayer film on a substrate, and the phase shift multilayer film is made of a compound containing a metal and silicon and has a film stress of 400 MPa or less. It consists of a stress layer, a compound containing metal and silicon, and is mixed with ammonia perwater obtained by mixing 30% by mass ammonia water, 30% by mass hydrogen peroxide solution and water at a volume ratio of 1: 1: 8 at 23 ° C. The amount of decrease in film thickness when immersed for a period of time is 1.0 nm or less, and has a chemical resistant layer provided adjacent to the low stress layer so as to form the outermost layer of the phase shift multilayer film .

In the phase shift mask blank of the present invention, a phase shift multilayer film is formed as a phase shift multilayer film on a substrate (transparent substrate) through which exposure light such as quartz and CaF ₂ is transmitted. A phase shifter portion in which a phase shift multilayer film is present on a substrate so that the transmittance at a wavelength is several to several tens% (particularly preferably 3 to 40%) and when a phase shift mask is used. Is set so that the phase difference between the light transmitted through the substrate and the light transmitted through the substrate exposed portion where no phase shift multilayer film is present is preferably 180 ± 5 degrees.

  If a specific example is given as a phase shift mask blank provided with such a phase shift multilayer film, for example, as shown in FIG. 1A, a single layer of low stress as a phase shift multilayer film 2 is formed on a substrate 1. The layer 21 and one chemical resistant layer 22 are formed.

  In the phase shift mask blank of the present invention, the phase shift film is composed of a multilayer film, and a low stress layer is formed as one layer thereof. The film stress of the low stress layer is 400 MPa or less, preferably 400 MPa or less. It is. Thereby, the amount of change in warpage before and after producing a phase shift mask by patterning a phase shift mask blank with a small warp, in particular, a phase shift multilayer film of the phase shift mask blank, is preferably 0.5 μm or less. Can be a phase shift mask blank of 0.3 μm or less.

  Further, if such a film stress is provided, a warp reduction effect can be provided with a film thickness of about 10.0 to 50.0 nm. Predetermined optical characteristics can be obtained by suppressing the thickness of the multilayer film to 80.0 nm or less, and the phase shift multilayer film does not become thick while satisfying various characteristics such as chemical resistance and optical characteristics.

  This low-stress layer is composed of a compound containing metal and silicon, and in particular, a compound containing metal, silicon, oxygen and / or nitrogen, particularly an oxide of metal and silicon (MSiO: M represents a metal element) Alternatively, it is preferably a metal and silicon oxynitride (MSiON: M represents a metal element), and the metal (M) includes at least one selected from molybdenum and zirconium. preferable. Examples of such materials include, but are not limited to, molybdenum, zirconium and silicon oxide (MoZrSiO), and molybdenum, zirconium and silicon oxynitride (MoZrSiON). In this case, the composition of MoZrSiO is preferably Mo: 0.2 to 25 atomic%, Zr: 0.2 to 25 atomic%, Si: 10 to 42 atomic%, O: 30 to 60 atomic%, and MoZrSiON The composition of Mo: 0.2-25 atomic%, Zr: 0.2-25 atomic%, Si: 10-57 atomic%, O: 2-20 atomic%, N: 5-57 atomic% Is preferred.

  On the other hand, in the phase shift mask blank of the present invention, as one layer of the phase shift multilayer film, a chemical resistant layer is formed adjacent to the low stress layer so as to be positioned on the outermost layer of the phase shift multilayer film. The chemical resistant layer has a film thickness when immersed in ammonia perwater obtained by mixing 30% by mass ammonia water, 30% by mass hydrogen peroxide solution and water at a volume ratio of 1: 1: 8 at 23 ° C. for 1 hour. The amount of decrease is 1.0 nm or less.

  Although the warp can be reduced by forming the low-stress layer as described above as one layer of the phase shift multilayer film, the low-stress layer has chemical resistance and optical characteristics (especially in-plane distribution) during cleaning. It tends to be inferior. Therefore, in the present invention, a chemical resistant layer is provided on the outermost layer of the phase shift multilayer film.

  The film thickness of the chemical resistant layer is preferably 5 nm or more, particularly preferably 10 nm or more. If the film thickness is less than 5 nm, chemical resistance may not be obtained. On the other hand, in order to exhibit the effect of the above-described low stress layer, the film thickness of the chemical resistant layer is 70 nm or less, preferably 30 nm or less. If the film thickness exceeds 70 nm, chemical resistance can be obtained, but the film stress as the whole phase shift multilayer film increases, and the warpage may not be reduced.

  This chemical-resistant layer is composed of a compound containing metal and silicon, and in particular, a compound containing metal, silicon and oxygen and / or nitrogen, particularly an oxide of metal and silicon (MSiO: M represents a metal element) Alternatively, it is preferably a metal and silicon oxynitride (MSiON: M represents a metal element), and the metal (M) includes at least one selected from molybdenum and zirconium. preferable. Examples of such materials include, but are not limited to, molybdenum, zirconium and silicon oxide (MoZrSiO), and molybdenum, zirconium and silicon oxynitride (MoZrSiON). In this case, the composition of MoZrSiO is preferably Mo: 0.2 to 25 atomic%, Zr: 0.2 to 25 atomic%, Si: 10 to 42 atomic%, O: 30 to 60 atomic%, and MoZrSiON The composition of Mo: 0.2-25 atomic%, Zr: 0.2-25 atomic%, Si: 10-57 atomic%, O: 2-20 atomic%, N: 5-57 atomic% Is preferred.

  If the metal content of the chemical resistant layer is lowered, the chemical resistance can be further improved. However, if the metal content is lowered, the optical characteristics of the film cannot be obtained (particularly, the absorption coefficient of the film becomes small), and the optical characteristics of the entire phase shift multilayer film may not be satisfied as it is. In this case, an optical adjustment layer can be formed as one layer of the phase shift multilayer film adjacent to the low stress layer (that is, adjacent to the substrate side of the low stress layer).

  As a phase shift mask blank provided with such a phase shift multilayer film, an optical adjustment layer 20, a low stress layer 21 and a chemical resistant layer as a phase shift multilayer film 2 on a substrate 1 as shown in FIG. What formed 22 in order is mentioned.

  In particular, it is desirable to provide an optical adjustment layer having a large extinction coefficient. In addition, the optical adjustment layer desirably has a higher metal content than the above-described low-stress layer or chemical-resistant layer, and in this way, the metal content of the chemical-resistant layer can be set low. It is possible to obtain a phase shift multilayer film with higher chemical resistance while maintaining predetermined optical characteristics.

  The film thickness of the optical adjustment layer is preferably 2.0 to 50.0 nm. If the film thickness of the optical adjustment layer is less than 2.0 nm, it may be difficult to control the in-plane distribution of the optical characteristics of the film itself. If the film thickness exceeds 50.0 nm, chemical resistance is obtained. There is a risk that sufficient chemical resistance cannot be obtained because a sufficient film thickness cannot be secured in the chemical resistant layer.

  This optical adjustment layer is composed of a compound containing a metal and silicon, and in particular, a compound containing a metal, silicon, oxygen and / or nitrogen, particularly an oxide of metal and silicon (MSiO: M represents a metal element). Alternatively, it is preferably a metal and silicon oxynitride (MSiON: M represents a metal element), and the metal (M) includes at least one selected from molybdenum and zirconium. preferable. Examples of such materials include, but are not limited to, molybdenum, zirconium and silicon oxide (MoZrSiO), and molybdenum, zirconium and silicon oxynitride (MoZrSiON). In this case, the composition of MoZrSiO is preferably Mo: 0.2 to 25 atomic%, Zr: 0.2 to 25 atomic%, Si: 10 to 42 atomic%, O: 5 to 50 atomic%, and MoZrSiON The composition of Mo: 0.2 to 25 atomic%, Zr: 0.2 to 25 atomic%, Si: 10 to 57 atomic%, O: 0.2 to 20 atomic%, N: 0.2 to 50 atomic% % Is preferred.

  In addition, when a desired optical characteristic is acquired only by the low stress layer and chemical-resistant layer mentioned above, it is not necessary to provide an optical adjustment layer. As such, for example, by adjusting the metal content of the low stress layer to be higher than that of the chemical resistant layer, the chemical resistant layer has the chemical resistance as described above (that is, 30% by mass ammonia water and 30 mass% hydrogen peroxide solution and water are mixed at a volume ratio of 1: 1: 8, and the amount of decrease in film thickness is 1.0 nm or less when immersed in ammonia perwater for 1 hour at 23 ° C.) In addition, this corresponds to a case where predetermined optical characteristics can be obtained within a range where the film stress of the low stress layer does not exceed 400 MPa.

  Each layer constituting such a phase shift multilayer film is made of a metal target, a silicon target, a metal, and a metal target appropriately selected according to the composition of the layer to be formed under an inert gas atmosphere such as neon, argon, krypton, and xenon. A film can be formed by sputtering using a silicon target or the like.

  As the target composed of metal and silicon, it is desirable to use a sintered target composed of molybdenum and silicon or a sintered target composed of molybdenum, zirconium and silicon, which can easily obtain a dense and high-purity target.

  In addition, each layer constituting the phase shift multilayer film is a compound containing a metal and silicon, for example, a compound containing a metal, silicon, oxygen and / or nitrogen (metal and silicon oxide (MSiO: M is Reactive gas such as a gas containing oxygen and a gas containing nitrogen together with an inert gas when it is composed of metal oxynitride (MSiON: M is a metal element)) For example, it can be formed by reactive sputtering in which nitrogen gas, oxygen gas, various nitrogen oxide gases, carbon oxide gas, or the like is appropriately introduced.

  For example, when forming a MoZrSiON film, a sintered target made of molybdenum, zirconium, and silicon is used as a target, and the film is formed by reactive sputtering using a sputtering gas containing argon gas, nitrogen gas, and oxygen gas. be able to.

  Specifically, a low stress layer and a chemical resistant layer in the phase shift multilayer film are formed by using one type of target made of metal and silicon and performing sputtering by appropriately adjusting the concentration of the reactive gas in the sputtering gas. A film can be formed. In order to secure the chemical resistance of the chemical resistant layer, the metal content of the chemical resistant layer can be lowered by reducing the reactive gas concentration when forming the chemical resistant layer. In addition, when forming the optical adjustment layer, before forming the low-stress layer, as with the low-stress layer and the chemical-resistant layer, by appropriately adjusting the concentration of the reactive gas in the sputtering gas, sputtering is performed. A film can be formed, and when the metal content of the optical adjustment layer is lowered, the film can be formed by sputtering with the reactive gas concentration being further lowered.

  Further, as described above, the phase shift mask blank of the present invention can also be formed by a method of forming a phase shift multilayer film using one type of target, but is composed of a metal target, a silicon target, metal and silicon. It is more preferable to form a film using two or more kinds of targets having different composition ratios of metal and silicon selected from the targets. FIG. 2 is a diagram showing an example of a method for producing the phase shift mask blank of the present invention. In this case, first, two types of targets 102a and 102a made of metal and silicon and silicon targets 102b and 102b were provided in the sputtering chamber 101 of the sputtering apparatus (in FIG. 2, two targets are shown). Using the apparatus (FIG. 2 (A)), while introducing a predetermined sputtering gas from the sputtering gas inlet 103, electric power is simultaneously applied to the plurality of targets 102a, 102a, 102b, 102b to perform discharge, and sputtering is performed. Films are formed while synthesizing film components scattered from the respective targets 102a, 102a, 102b, and 102b. In FIG. 2, reference numeral 104 denotes an exhaust port.

  At this time, the substrate 1 is preferably rotated so that the film components from the respective targets are uniformly mixed. In general, the deposition rate is proportional to the power applied to the target, so that a desired film composition can be obtained by adjusting the combination of the discharge power applied to each target.

  For example, when manufacturing a phase shift mask blank as shown in FIG. 1A, first, the power applied to the target 102a made of metal and silicon is increased, and the power applied to the silicon target 102b is decreased. A low stress layer 21 having a high metal content can be formed (FIG. 2B). Next, the chemical-resistant layer 22 having a low metal content can be formed by reducing the power applied to the target 102a made of metal and silicon and increasing the power applied to the silicon target 102b (FIG. 3C )).

  In the case of providing the optical adjustment layer, the film can be similarly formed by appropriately adjusting the power applied to the metal and silicon target 102a and the silicon target 102b before forming the low stress layer. When the metal content of the optical adjustment layer is lowered, the film can be formed by lowering the power applied to the target 102a made of metal and silicon and further increasing the power applied to the silicon target 102b.

  In addition, when each layer of the phase shift multilayer film is formed by reactive sputtering using a reactive gas, sputtering is performed as in the case of sputtering using one type of target as described above, together with adjustment of power applied to the target. Adjustment of the concentration of the reactive gas contained in the gas can be used in combination, thereby enabling more precise control of the film composition.

  Moreover, in this invention, it is preferable to form into a film by making sputtering pressure at the time of forming a low stress layer into a film by sputtering 0.2 Pa or more, especially 0.2-1 Pa. If the gas pressure is less than 0.2 Pa, the stress may not be sufficiently reduced. By forming the low-stress layer in this way, it becomes possible to further reduce the amount of change in the warp of the substrate when producing the phase shift mask from the obtained phase shift mask blank. It becomes possible to make it 0.5 μm or less, especially 0.3 μm or less.

  On the other hand, the sputtering pressure when the chemical resistant layer is formed by sputtering is preferably less than 0.2 Pa, particularly preferably 0.04 to 0.18 Pa. By forming the film at a low gas pressure, it becomes possible to increase the energy at which the sputtered particles collide with the substrate, and a high-density film is formed. This makes it possible to obtain a film particularly excellent in chemical resistance. Is possible. If the gas pressure is 0.2 Pa or more, not only sufficient chemical resistance cannot be obtained, but also the effect of uniforming the in-plane distribution of the optical characteristics of the entire phase shift multilayer film described later may not be obtained. When the chemical resistant layer is formed in this manner, sufficient chemical resistance for the chemical resistant layer located on the outermost layer of the phase shift multilayer film of the obtained phase shift mask blank, for example, 30% by mass ammonia water and 30% by mass Obtaining excellent resistance that the amount of decrease in film thickness is 1.0 nm or less when immersed for 1 hour at 23 ° C. in ammonia perwater prepared by mixing hydrogen peroxide and water in a volume ratio of 1: 1: 8. Accordingly, it is possible to suppress a change in optical characteristics due to the chemical treatment when the phase shift mask is manufactured from the phase shift mask blank.

  Further, as described above, when the low stress layer is formed at a sputtering pressure of 0.2 Pa or more, in the low stress layer, the phase difference which is one of the optical characteristics tends to exhibit a large in-plane distribution in the central portion. By setting the sputtering pressure at the time of forming the chemical resistant layer to less than 0.2 Pa, the phase difference of the chemical resistant layer tends to have a small in-plane distribution at the center, so the entire phase shift multilayer film It is also possible to make the in-plane distribution of the optical characteristics uniform.

  In the present invention, the sputtering method may be one using a direct current power source or one using a high frequency power source, and may be a magnetron sputtering method or a conventional method.

  In the present invention, it is also preferable to provide a chromium-based light shielding film and / or a chromium-based antireflection film on the phase shift multilayer film. As such, a phase shift mask blank in which a chromium-based light-shielding film 3 is provided on a phase shift multilayer film 2 as shown in FIG. 3, or a phase shift multilayer film 2 as shown in FIG. A phase shift mask blank provided with a chromium-based light-shielding film 3 and further formed with a chromium-based antireflection film 4 for reducing reflection from the chromium-based light-shielding film 3 on the chromium-based light-shielding film 3, and further shown in FIG. Such a phase shift mask blank formed in the order of the phase shift multilayer film 2, the first chrome-based antireflection film 4, the chrome-based light-shielding film 3, and the second chrome-based antireflection film 4 ′ from the substrate 1 side. . 3-5, 21 is a low-stress layer and 22 is a chemical-resistant layer.

  In this case, it is preferable to use a chromium oxide carbide (CrOC) film, a chromium oxynitride carbide (CrONC) film, or a laminate of these as the chromium-based light shielding film or the chromium-based antireflection film.

  Such a chromium-based light-shielding film or chromium-based antireflection film uses a target obtained by adding chromium alone or one of chromium, oxygen, nitrogen, carbon, or a combination thereof, and neon, argon, krypton, or the like. A film can be formed by reactive sputtering using a sputtering gas in which carbon dioxide gas is added as a carbon source to an active gas.

Specifically, in the case of forming a CrONC film, as a sputtering gas, a gas containing carbon such as CH ₄ , CO ₂ and CO, a gas containing nitrogen such as NO, NO ₂ and N ₂ , and CO ₂ One or more of gases containing oxygen such as NO, O, or O ₂ may be introduced, or a gas in which an inert gas such as Ar, Ne, or Kr is mixed may be used. In particular, it is preferable to use CO ₂ gas or CO gas as the carbon source and oxygen source gas from the viewpoints of in-plane uniformity of the substrate and controllability during production. As an introduction method, various sputtering gases may be separately introduced into the chamber, or some gases may be combined or all gases may be mixed and introduced.

  In the CrOC film, Cr is 20 to 95 atomic%, particularly 30 to 85 atomic%, C is 1 to 30 atomic%, particularly 5 to 20 atomic%, and O is 1 to 60 atomic%, particularly 5 to 50 atomic%. In addition, the CrONC film has a Cr of 20 to 95 atomic%, particularly 30 to 80 atomic%, C of 1 to 20 atomic%, particularly 2 to 15 atomic%, O of 1 to 60 atomic%, In particular, 5 to 50 atom%, N is preferably 1 to 30 atom%, and particularly preferably 3 to 20 atom%.

  The phase shift mask of the present invention is obtained by patterning the phase shift multilayer film of the phase shift mask blank as described above.

  For example, if a specific example is given, the phase shift multilayer film 2 of the phase shift mask blank of the present invention shown in FIG. 1 (A) as shown in FIG. 6 may be patterned. This phase shift mask is provided with a patterned phase shifter portion 2a and a substrate exposed portion 1a therebetween.

  When a phase shift mask as shown in FIG. 6 is manufactured, as shown in FIG. 7A, after forming the phase shift multilayer film 2 on the substrate 1 as described above, the resist film 5 is formed. 7B, the resist film 5 is patterned by a lithography method as shown in FIG. 7B, and the phase shift multilayer film 2 is etched as shown in FIG. As shown in (D), a method of removing the resist film 5 can be adopted. In this case, application of the resist film, patterning (exposure, development), etching, and removal of the resist film can be performed by a known method. However, the phase shift multilayer film of the present invention is etched with a single etching gas. Is possible.

  When a chromium-based light-shielding film and / or a chromium-based antireflection film (chromium-based film) is formed on the phase shift multilayer film, a chromium-based light-shielding film and / or a chromium-based antireflection film in a region necessary for exposure. After the film is removed by etching and the phase shift multilayer film is exposed on the surface, the phase shift multilayer film is patterned in the same manner as described above to form a chromium-based film on the outer peripheral edge of the substrate surface as shown in FIG. It is also possible to obtain a phase shift mask with the chromium-based light shielding film 3 remaining in the case of FIG. In addition, a resist is coated on the chromium film, patterned, the chromium film and the phase shift multilayer film are patterned by etching, and only the chromium film in the region necessary for exposure is removed by selective etching. The phase shift mask can be obtained by exposing the phase shift pattern to the surface.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated concretely, this invention is not limited to the following Example.

[Example 1]
A phase shift mask blank in which a phase shift multilayer film having a three-layer structure as shown in FIG. 1B was formed on a substrate by the following method was produced.

  A DC sputtering apparatus provided with two targets as shown in FIG. 9 was used for forming the phase shift multilayer film. (Same for the following film formation). In FIG. 9, 1 is a substrate, 101 is a chamber, 102a and 102b are targets, 103 is a sputtering gas introduction port, 104 is an exhaust port, 105 is a substrate turntable, and 106a and 106b are power supplies.

Using a MoZrSi ₄ sintered body and a Si single crystal as a sputtering target, first, a discharge power of 560 W is applied to the MoZrSi ₄ target and a discharge power of 1000 W is applied to the Si target, and sputter film formation is performed while rotating the substrate at 30 rpm. An optical adjustment layer having a thickness shown in Table 1 was formed on an inch square quartz substrate. At this time, a mixed gas of 8 cm ³ / min Ar, 20 cm ³ / min N ₂ and 5 cm ³ / min O ₂ was introduced as a sputtering gas. The gas flow rates are all values at 0 ° C. and 1013 hPa (1 atm) (hereinafter the same). The gas pressure during sputtering was set to 0.15 Pa.

Next, the discharge power was changed so that the MoZrSi ₄ target was 430 W and the Si target was 1000 W, and the sputtering gas was a mixture of 15 cm ³ / min Ar, 100 cm ³ / min N ₂ and 1 cm ³ / min O ₂ . The gas was changed to gas, and a low stress layer having a thickness shown in Table 1 was formed at a gas pressure of 0.25 Pa while rotating the substrate at 30 rpm.

Further, the discharge power was changed so that the MoZrSi ₄ target was 430 W and the Si target was 1000 W, and the sputtering gas was a mixed gas of 5 cm ³ / min Ar, 50 cm ³ / min N _2, and 1 cm ³ / min O ₂ . The chemical resistant layer having a thickness shown in Table 1 was formed at a gas pressure of 0.1 Pa while rotating the substrate at 30 rpm.

  Table 1 shows the gas pressure during film formation, the total content of Mo and Zr (Mo + Zr), the film thickness, and the stress in each layer. The total content of Mo and Zr (Mo + Zr) in each layer is a value estimated from the discharge power during sputtering. The stress is a value obtained by measuring the film stress of a film obtained by forming each layer on the substrate independently under the film forming conditions shown in each example and comparative example.

  The following method evaluated the phase shift multilayer film of the phase shift mask blank obtained by the above method.

Substrate warpage The warpage of the substrate before and after film formation was measured with a flatness tester, and the amount of change in warpage was evaluated. The results are shown in Table 2.

Chemical resistance ammonia water: hydrogen peroxide water: water was measured and evaluated for changes in transmittance and film thickness reduction when immersed in ammonia excess water at 1: 1: 8 (volume ratio) at 23 ° C. for 1 hour. The measurement wavelength of the transmittance change is 193 nm. In addition, the amount of film thickness reduction is a contact type masking part of the phase shift multilayer film on the substrate with adhesive tape and performing the above immersion treatment, and after the treatment, the adhesive tape is peeled off and the step between the mask part and the non-mask part is contacted. It was determined by measuring with a step gauge. The results are shown in Table 2.

The phase shift amount given by the phase shift multilayer film on the phase difference in-plane distribution substrate is measured from the center of the substrate surface on which the phase shift multilayer film is formed toward one vertex of the square substrate surface. The difference between the maximum and minimum values was evaluated as an in-plane distribution. The results are shown in Table 2. The measurement wavelength is 193 nm.

[Examples 2 and 3, Comparative Example 1]
In the film formation of the low stress layer and the chemical resistant layer, except that the gas pressure was changed by changing the conductance of the main valve of the sputtering apparatus, and the film thickness was changed as shown in Table 1 by adjusting the film forming time. Prepared a phase shift mask blank in which a phase shift multilayer film having a three-layer structure as shown in FIG. 1B was formed on a substrate under the same conditions as in Example 1 and evaluated in the same manner as in Example 1. did. The results are shown in Tables 1 and 2.

[Comparative Example 2]
In the formation of the low stress layer, the gas pressure was changed by changing the conductance of the main valve of the sputtering apparatus, the film thickness was changed as shown in Table 1 by adjusting the film formation time, and the chemical resistant layer A phase shift mask blank in which a phase shift multilayer film having a two-layer structure not having a chemical resistance layer is formed under the same conditions as in Example 1 except that the film was not formed. Evaluation was performed in the same manner. The results are shown in Tables 1 and 2.

  From the results shown in Tables 1 and 2, it was confirmed that the phase shift mask blanks obtained in the examples were excellent in optical characteristics and chemical resistance and had small warpage. From this result, it can be seen that a phase shift mask having excellent optical characteristics and chemical resistance and low warpage can be obtained from this phase shift mask blank.

It is sectional drawing which shows an example of the structure of the phase shift mask blank of this invention. It is explanatory drawing which shows an example of the method of manufacturing the phase shift mask blank of this invention. It is sectional drawing which shows the structure of the phase shift mask blank which provided the chromium-type light shielding film. It is sectional drawing which shows the structure of the phase shift mask blank which provided the chromium-type light shielding film and the chromium-type antireflection film. It is sectional drawing which shows the structure of the phase shift mask blank which provided the 1st chromium-type antireflection film, the chromium-type light shielding film, and the 2nd chromium-type antireflection film. It is sectional drawing which shows an example of the phase shift mask of this invention. It is a figure for demonstrating the manufacturing method of a phase shift mask, (A) is the state which formed the resist film, (B) is the state which patterned the resist film, (C) is the state which etched, (D () Is a view showing a state where the resist film is removed. It is sectional drawing which shows the other example of the phase shift mask of this invention. It is the schematic of the direct current | flow sputtering apparatus used by the Example and the comparative example. It is a figure explaining the principle of a halftone type phase shift mask, (B) is the elements on larger scale of the X section of (A). It is sectional drawing which shows the structure of the conventional phase shift mask blank. It is sectional drawing which shows the structure of the conventional phase shift mask.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 1a Substrate exposed part 2 Phase shift multilayer film 2 ′ Phase shift film 2a Phase shifter part 20 Optical adjustment layer 21 Low stress layer 22 Chemical resistant layer 3 Chrome light shielding film 4, 4 ′ Chrome antireflection film 5 Resist film

Claims (9)

  A phase shift mask blank comprising a phase shift multilayer film on a substrate, wherein the phase shift multilayer film is made of a compound containing metal and silicon, and a film stress is 400 MPa or less, a metal and silicon The film thickness of the film when immersed in ammonia perwater for 1 hour at 23 ° C. in a mixture of 30% by mass ammonia water, 30% by mass hydrogen peroxide solution and water at a volume ratio of 1: 1: 8. A phase shift mask blank having a chemical resistance layer provided adjacent to the low-stress layer so that the amount of decrease is 1.0 nm or less and forms the outermost layer of the phase shift multilayer film.   The phase shift mask blank according to claim 1, wherein the phase shift multilayer film further comprises an optical adjustment layer made of a compound containing metal and silicon and provided adjacent to the low stress layer.   The phase shift mask blank according to claim 2, wherein the metal content of the optical adjustment layer is the highest among the low stress layer, the chemical resistance layer and the optical adjustment layer constituting the phase shift multilayer film.   The phase shift mask blank according to any one of claims 1 to 3, wherein the compound containing metal and silicon is a compound containing metal, silicon, and oxygen and / or nitrogen.   The phase shift mask blank according to any one of claims 1 to 4, wherein the metal contains at least one selected from molybdenum and zirconium.   6. The phase shift mask blank according to claim 1, further comprising a chromium-based light shielding film and / or a chromium-based antireflection film on the phase shift multilayer film.   7. A phase shift mask comprising a phase shift multilayer film of the phase shift mask blank according to claim 1 formed as a pattern.   It is a method of manufacturing the phase shift mask blank of any one of Claim 1 thru | or 6, Comprising: The said phase shift multilayer film is a metal selected from the target which consists of a metal target, a silicon target, and a metal, and silicon, and silicon. A method for producing a phase shift mask blank, comprising forming a film on a transparent substrate by sputtering using two or more kinds of targets having different composition ratios.   A pattern transfer method comprising performing pattern exposure on a photoresist using the phase shift mask according to claim 7.

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