JP2004318084A - Phase shift mask blank, phase shift mask, method for manufacturing phase shift mask blank and method for manufacturing phase shift mask - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a phase shift mask blank having satisfactory optical characteristics, excellent chemical resistance, and a small level difference on the side face of an etching pattern during forming a pattern. <P>SOLUTION: The blank has a phase shift multilayer film consisting of two or more layers of films on a substrate. The phase shift multilayer film is composed of a film essentially comprising a molybdenum silicide compound and a film essentially comprising a zirconium silicide compound, and the film in the outermost layer of the phase shift multilayer film essentially comprises a zirconium silicide compound. In the method for manufacturing a phase shift mask blank, a film comprising a molybdenum silicide compound and a film comprising a zirconium silicide compound are deposited as the phase shift multilayer film by using a molybdenum silicide target and a zirconium silicide target and by using oxygen or nitrogen as the sputtering gas, and a film comprising a zirconium silicide compound is deposited as the outermost layer film. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a phase shift mask blank and a phase shift mask used for manufacturing a semiconductor integrated circuit and the like, and a method of manufacturing the phase shift mask blank and the phase shift mask, and in particular, attenuates light having an exposure wavelength by a phase shift multilayer film. The present invention relates to a halftone type phase shift mask, a phase shift mask blank used therefor, and a method of manufacturing these.

  Photomasks used for 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 light-transmitting substrate. A predetermined pattern is formed on the light-shielding film of the mask blank by applying a photolithography method and using ultraviolet rays, electron beams, or the like. In recent years, pattern miniaturization has rapidly progressed in response to market demands for higher integration of semiconductor integrated circuits and the like, and this has been dealt with by shortening the exposure wavelength.

  However, while shortening the exposure wavelength improves resolution, it also causes a decrease in the depth of focus, resulting in a decrease in process stability and a negative effect on product yield.

  One effective pattern transfer method for such a problem is a phase shift method, 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, as shown in FIGS. 9A and 9B, on a phase shift mask having a phase shift film 2 ′ formed on a substrate 1. The phase shifter portion 2a forming the pattern portion and the substrate exposed portion 1a where the substrate without the phase shifter is exposed are exposed. By setting the phase difference of light transmitted through both to approximately 180 °, The light intensity at the interference portion becomes zero due to the interference of light at the pattern boundary portion, and the contrast of the transferred image can be improved. In addition, by using the phase shift method, it is possible to increase the depth of focus for obtaining the required resolution, as compared with a case where a normal mask having a general light shielding pattern made of a chrome film or the like is used. It is possible to improve the resolution and the margin of the exposure process.

  The above-mentioned phase shift masks can be practically roughly classified into a complete transmission type phase shift mask and a halftone type phase shift mask depending on the light transmission characteristics of the phase shifter. The complete transmission type phase shift mask is a mask in which the light transmittance of the phase shifter portion is equivalent to that of the substrate exposed portion and which is transparent to the exposure wavelength. In the halftone phase shift mask, the light transmittance of the phase shifter is about several% to several tens% of the exposed part of the substrate.

  FIG. 10 shows the basic structure of a halftone type phase shift mask blank, and FIG. 11 shows the basic structure of a halftone type phase shift mask. The halftone type phase shift mask blank 50 shown in FIG. 10 has a halftone phase shift film 2 ′ formed on almost the entire surface of the transparent substrate 1. The halftone type phase shift mask 60 in FIG. 11 is obtained by patterning the phase shift film 2 ′, and includes a phase shifter 2 a for forming a pattern portion on the substrate 1 and a substrate exposed portion 1 a having no phase shifter. Consists of Here, the light transmitted through the phase shifter 2a is phase-shifted with respect to the light transmitted through the substrate exposing portion 1a, and the transmittance of the phase shifter 2a is set to a light intensity that is not sensitive to the resist on the substrate to be transferred. Is set. Therefore, it has a light blocking function of substantially blocking exposure light.

  As the halftone type phase shift mask, there is a single layer type halftone type phase shift mask which has a simple structure and is easy to manufacture. As this single-layer halftone phase shift mask, one having a phase shifter made of a MoSi-based material such as MoSiO or MoSiON has been proposed (for example, see Patent Document 1).

  What is important in the phase shift mask blank used for such a phase shift mask is that the transmittance at the exposure wavelength used, the phase difference, the reflectance, the optical properties such as the refractive index, etc. are satisfied, and the chemical resistance etc. That is, durability and low defects must be realized.

  However, in the single-layer halftone phase shift film, when the optical characteristics are set to a desired value, the film composition is uniquely determined. Therefore, it is possible to obtain a phase shift film satisfying other required characteristics. It was difficult.

  In order to avoid this problem, it has been considered to form a phase shift multilayer film having a plurality of layers for satisfying optical characteristics and a plurality of layers for satisfying other characteristics such as chemical resistance. However, the film structure and film composition that actually satisfy the optical characteristics and also satisfy the chemical resistance were unknown.

  Further, as shown in FIG. 13, a phase shift multilayer film composed of a plurality of films is formed, for example, when a phase shift multilayer film 2 composed of a surface film 2s and a lower film 2d is formed on a substrate 1. When a pattern is formed on the phase shift multilayer film 2 to form a phase shift mask, there is a problem that a step 14 is easily generated on the side surface of the etching pattern.

JP-A-7-140635

  The present invention has been made in order to solve the above problems, and while satisfying optical characteristics, has excellent chemical resistance, and a phase shift mask blank having a sufficiently small step on the side of an etching pattern when a pattern is formed. It is an object of the present invention to provide a phase shift mask using the same and a method for manufacturing the same.

  The present invention for achieving the above object is a phase shift mask blank, comprising at least a phase shift multilayer film composed of two or more films on a substrate, wherein the phase shift multilayer film is formed of molybdenum silicide. The phase shift multilayer film is composed of a film mainly composed of a compound and a film mainly composed of a zirconium silicide compound, and the film of the outermost layer is a film mainly composed of a zirconium silicide compound. It is a phase shift mask blank (Claim 1).

  As described above, in the phase shift mask blank in which the phase shift multilayer film is formed on the substrate, the phase shift multilayer film includes a film mainly containing a molybdenum silicide compound and a film mainly containing a zirconium silicide compound, and If the film on the outermost layer of the phase shift multilayer film is a film containing a zirconium silicide compound as a main component, while satisfying desired optical characteristics, it is excellent in chemical resistance, and furthermore, when a pattern is formed, a step on an etching pattern side surface is formed. Can be a sufficiently small phase shift mask blank.

In this case, it is preferable that the molybdenum silicide compound is a compound of molybdenum silicide and oxygen and / or nitrogen, and the zirconium silicide compound is a compound of zirconium silicide and oxygen and / or nitrogen (claim 2).
As described above, when the molybdenum silicide compound and the zirconium silicide compound that are the main components of each layer of the phase shift multilayer film are compounds with oxygen and nitrogen, respectively, each layer of the phase shift multilayer film has a desired transmittance, chemical resistance, and the like. A phase shift mask blank having the following characteristics can be obtained.

In this case, a chromium-based light-shielding film and / or a chromium-based antireflection film can be formed on the phase shift multilayer film.
As described above, by forming the chromium-based light-shielding film and / or the chromium-based antireflection film on the phase shift multilayer film, more precise patterning becomes possible, and further miniaturization of the semiconductor integrated circuit, higher It is possible to sufficiently cope with integration.

The present invention is a phase shift mask characterized in that a pattern is formed on a phase shift multilayer film of the phase shift mask blank of the present invention (claim 4).
The phase shift mask blank of the present invention has a desired optical property of the phase shift multilayer film, is excellent in chemical resistance, and further, when a pattern is formed on the phase shift multilayer film, a step is hardly generated on a side surface of the etching pattern. The phase shift mask having the pattern formed thereon has high quality.

  Further, the present invention is a method for manufacturing a phase shift mask blank, at least including a step of sputtering a phase shift multilayer film composed of two or more layers on a substrate, wherein the sputtering film formation is at least By using a target containing molybdenum silicide as a component and a target containing zirconium silicide as a component, using a sputtering gas containing at least oxygen or nitrogen, and changing the power applied to each of the targets, the phase shift multilayer film A film mainly composed of a molybdenum silicide compound and a film mainly composed of a zirconium silicide compound are formed, and a film mainly composed of a zirconium silicide compound is formed as a film of the outermost layer of the phase shift multilayer film. Phase shift mask bra A click method for producing (claim 5).

  As described above, when a phase shift multilayer film composed of a plurality of layers is formed on a substrate by sputtering, a target containing molybdenum silicide as a component and a target containing zirconium silicide as a component are used, and the power applied to each target is reduced. By changing, a film of a molybdenum silicide compound and a film of a zirconium silicide compound are formed as a phase shift multilayer film, and a film of a zirconium silicide compound is formed as a film of the outermost layer, thereby satisfying desired optical characteristics. In addition, it is possible to manufacture a phase shift mask blank excellent in chemical resistance and having a sufficiently small step on the side of the etching pattern when a pattern is formed.

The present invention is a method for manufacturing a phase shift mask, wherein a pattern is formed by a lithography method on a phase shift multilayer film of a phase shift mask blank manufactured by the manufacturing method of the present invention. ).
Thus, in the phase shift mask blank manufactured by the manufacturing method of the present invention, the phase shift multilayer film has desired optical characteristics, is excellent in chemical resistance, and further, when a pattern is formed, there is a step on the side of the etching pattern. Since a phase shift mask is unlikely to occur, a high-quality phase shift mask can be manufactured by forming a pattern thereon by a lithography method and manufacturing a phase shift mask.

  As described above, according to the present invention, in a phase shift mask blank in which a phase shift multilayer film composed of a plurality of layers is provided on a substrate, the phase shift mask blank has desired optical properties, is excellent in chemical resistance, and has a pattern. It becomes possible to obtain a phase shift mask blank and a phase shift mask in which the step on the side of the etching pattern is sufficiently small when formed.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings, but the present invention is not limited thereto.
The inventor of the present invention has made intensive studies to solve the above-mentioned problems, and as a result, in a phase shift mask blank comprising a transparent substrate and a phase shift multilayer film composed of at least two layers, the phase shift multilayer film A molybdenum silicide compound film and a zirconium silicide compound film, and the outermost layer of the phase shift multilayer film is made of a zirconium silicide compound film, thereby satisfying optical characteristics, excellent chemical resistance, and etching. The present inventors have found that a phase shift mask blank and a phase shift mask having excellent pattern shapes can be obtained, and have accomplished the present invention.

  Further, the present invention provides a phase shift film formed of the above-mentioned phase shift multilayer film, and a chromium-based light-shielding film or a chromium-based antireflection film, or a multilayer film obtained by laminating one or more of each of these on the phase shift film. By forming them, these elements can be combined to perform more precise patterning, and can sufficiently cope with further miniaturization and higher integration of a semiconductor integrated circuit.

Hereinafter, the present invention will be described in more detail.
As shown in FIG. 1, a phase shift mask blank 5 according to the present invention comprises a phase shift multilayer film 2 composed of two or more layers on a substrate 1 through which exposure light such as quartz or CaF ₂ is transmitted. It is a film.
Further, as shown in FIG. 2, the phase shift mask 6 of the present invention is formed by pattern-forming the phase shift multilayer film 2 of the phase shift mask blank 5 of the present invention of FIG. 2a and a substrate exposed portion 1a therebetween.

  The phase shift multilayer film 2 is formed by a reactive sputtering method using a sputtering gas containing at least oxygen or nitrogen, and has, for example, a transmittance of several% to several tens% (particularly 3 to 40%) in exposure light. Preferably). When the phase shift mask 6 shown in FIG. 2 is used, the phase of the light transmitted through the phase shifter 2a is, for example, 180 ° ± 5 degrees different from the light transmitted through the substrate exposed portion 1a. Is to have. The phase shift multilayer film 2 is formed of, for example, an oxide, a nitride, or an oxynitride of a metal silicide.

  As shown in FIG. 1, in the phase shift mask blank 5 of the present invention, the phase shift multilayer film 2 includes a molybdenum silicide compound film 2M containing a molybdenum silicide compound as a main component and a zirconium compound containing a zirconium silicide compound as a main component of the outermost layer. It is composed of a silicide compound film 2Z.

  The present inventors have studied a method of arranging a metal silicide compound film having excellent chemical resistance and low metal content on the outermost layer of the phase shift multilayer film in order to improve the chemical resistance of the phase shift multilayer film. However, the present inventors have found that, in a phase shift multilayer film of a metal silicide compound composed of the same metal element, a step formed on a side surface of an etch pattern at the time of pattern formation is caused by a difference in the amount of metal contained in each layer film. Found to occur in. That is, as shown in FIG. 13, in order to improve the chemical resistance of the phase shift multilayer film 2 formed on the substrate 1, a metal silicide compound film having a low metal content is disposed as a surface film 2s on the outermost layer, and In the dry etching process at the time of formation, the dry etching speed of the surface film 2s having a low metal content and the dry etching speed of the lower film 2d having a high metal content are largely different. As a result, a step 14 is generated near the interface between the respective films. I knew it would.

  In order to solve this problem, the present inventors have searched for a combination of films having substantially equal etch rates in the dry etch process and excellent chemical resistance. As a result, the above problem is solved by providing a zirconium silicide compound film as a film provided on a surface layer for improving chemical resistance, and providing a molybdenum silicide compound film as a film provided thereunder for adjusting optical characteristics. Was found to be possible. That is, since the zirconium silicide compound has substantially the same etching rate in the dry etching step as the molybdenum silicide compound and has excellent chemical resistance, a step is generated in the etch pattern by using the zirconium silicide compound film as the outermost layer film. Can be prevented. By providing a molybdenum silicide compound film thereunder, desired optical characteristics can be obtained.

  Here, the zirconium silicide compound is desirably an oxide, nitride or oxynitride of zirconium. Similarly, the molybdenum silicide compound is desirably an oxide, nitride, or oxynitride of molybdenum silicide.

Further, when the zirconium concentration (mol concentration) of the zirconium silicide compound film and the molybdenum concentration (mol concentration) of the molybdenum silicide compound film are substantially equal, the etching speed in the dry etching step becomes substantially equal, and the step in the etching pattern is eliminated. Cheap.
Here, the ratio [Zr] / [Mo] of the zirconium concentration [Zr] in the outermost layer film and the molybdenum concentration [Mo] in the lower layer film is desirably in the range of 0.7 to 1.3. .

In the phase shift mask blank 5 shown in FIG. 1, the phase shift multilayer film 2 is composed of two layers of a molybdenum silicide compound film 2M and a zirconium silicide compound film 2Z, but the outermost film mainly comprises a zirconium silicide compound. It is not limited to two layers as long as it is constituted by a film as a component, and may be constituted by three or more layers.
Further, the composition of the film of each layer may include other components as long as the components are the main components. For example, it may include a film composition of another layer.

Next, a method for manufacturing a phase shift mask blank having the above-described phase shift multilayer film will be described.
FIG. 3 is a diagram illustrating an example of a method for manufacturing a phase shift mask blank according to the present invention. First, one or a plurality of molybdenum silicide targets 22M and zirconium silicide targets 22Z are mounted in a sputtering chamber 21 of the sputtering apparatus 20 (FIG. 3A). In FIG. 3, in addition to these, a silicon target 22S is arranged.

  A plurality of targets 22M, 22Z, 22S are simultaneously discharged and sputtered while introducing a predetermined sputter gas from the sputter gas inlet 23 to form a film while synthesizing film components scattered from the respective targets 22M, 22Z, 22S. I do. At this time, it is desirable that the substrate 1 be rotated so that the film components from the respective targets are uniformly mixed. In general, the film formation rate is proportional to the power applied to the target. Therefore, a desired film composition can be obtained by adjusting the discharge power applied to each target.

  For example, when manufacturing the phase shift mask blank 5 as shown in FIG. 1, when forming the molybdenum silicide compound film 2M, the electric power applied to the molybdenum silicide target 22M is increased, and The applied power is stopped or reduced to form a film 2M containing a molybdenum silicide compound as a main component (FIG. 3B). On the other hand, when the zirconium silicide compound film 2Z is formed, the power applied to the molybdenum silicide target 22M is stopped or reduced, and the power applied to the zirconium silicide target 22Z is increased, so that the zirconium silicide compound is mainly used. Is formed (FIG. 3C).

  In the formation of each layer, the ratio of metal to silicon in each layer is changed by changing the combination of power applied to the molybdenum silicide target 22M and the silicon target 22S or the combination of power applied to the zirconium silicide target 22Z and the silicon target 22S. Can be easily changed and adjusted.

  Note that in the deposition of each layer, a target not mainly used for the deposition of the layer may completely stop the discharge. However, if the target that is not mainly used is continuously discharged with the minimum power that discharges stably, the discharge becomes unstable at the start and end of the discharge of each target, causing particles to be generated or the target not discharging It is possible to prevent a component of the target being discharged from adhering to the substrate and to generate an arc when the target is discharged next, thereby preventing the film from being defective. In this case, the film composition of each layer includes the composition of a film other than the layer. However, if the amount is mixed with the minimum discharge power, the characteristics of each layer are not significantly affected.

  In the present invention, the sputtering method may be a method using a DC power supply or a high-frequency power supply, and may be a magnetron sputtering method, a conventional method, or another method.

  The composition of the sputtering gas is appropriately adjusted such that an inert gas such as argon or xenon and nitrogen gas or oxygen gas, various types of nitrogen oxide gas, carbon oxide gas, etc. are formed so that the phase-shifted multilayer film to be formed has a desired composition. To form a film.

  In this case, when it is desired to increase the transmittance of the formed phase shift film, a method of increasing the amount of a gas containing oxygen or nitrogen to be added to the sputtering gas so that a large amount of oxygen and nitrogen is taken into the film, or a method of sputtering It can be adjusted or changed by a method using molybdenum silicide or zirconium silicide to which a large amount of oxygen or nitrogen is added in advance to the target.

  Specifically, for example, when a MoSiON film is formed, it is preferable to use molybdenum silicide as a target and perform reactive sputtering with a sputtering gas containing an argon gas, a nitrogen gas, and an oxygen gas as a sputtering gas.

  The composition of the MoSiO film formed in the present invention is preferably Mo: 0.2 to 25 atomic%, Si: 10 to 42 atomic%, and O: 30 to 60 atomic%. The composition of the molybdenum silicide oxynitride (MoSiON) film is as follows: Mo: 0.2 to 25 at%, Si: 10 to 57 at%, O: 2 to 20 at%, N: 5 to 57 at%. Preferably, there is.

  In addition, as shown in FIG. 4, a chromium-based light-shielding film 3 is provided on the phase shift multilayer film 2, or as shown in FIG. The antireflection film 4 may be formed on the chrome-based light-shielding film 3. Further, as shown in FIG. 6, a phase shift multilayer film 2, a first chrome-based antireflection film 4, a chrome-based light-shielding film 3, and a second chromium-based antireflection film 4 'are formed in this order from the substrate 1. You can also.

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

  Such a chromium-based light-shielding film or chromium-based antireflection film is formed by using a target obtained by adding chromium alone or chromium to any of oxygen, nitrogen, and carbon, or a combination thereof, and using an inert gas such as argon or krypton. The film can be formed by reactive sputtering using a sputtering gas obtained by adding a carbon dioxide gas as a carbon source to a gas.

Specifically, when a CrONC film is formed, as a sputtering gas, a gas containing carbon such as CH ₄ , CO ₂ , CO, a gas containing nitrogen such as NO, NO ₂ , N ₂ , and CO ₂ We can NO, or introducing one or more kinds of gas containing oxygen such as O _2, also possible to use them in Ar, Ne, a mixed gas of inert gas Kr like. In particular, it is preferable to use a CO ₂ gas as a carbon source gas and an oxygen source gas from the viewpoint of uniformity in the substrate surface and controllability during production. As an introduction method, various sputtering gases may be separately introduced into the chamber, or several gases may be introduced together 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%, O is 1 to 60 atomic%, particularly 5 to 50 atomic%. It is preferable that the CrONC film has a Cr content of 20 to 95 at%, particularly 30 to 80 at%, C of 1 to 20 at%, particularly 2 to 15 at%, O of 1 to 60 at%, It is particularly preferred that 5 to 50 atomic% and N be 1 to 30 atomic%, particularly 3 to 20 atomic%.

The phase shift mask of the present invention is obtained by forming a pattern on the phase shift film of the phase shift mask blank obtained as described above.
Specifically, when manufacturing the phase shift mask 6 as shown in FIG. 2, as shown in FIG. 7A, the phase shift multilayer film 2 is formed on the substrate 1 as described above. Thereafter, a resist film 7 is formed, the resist film 7 is patterned by a lithography method as shown in FIG. 7B, and the phase shift multilayer film 2 is further formed as shown in FIG. After etching, a method of removing the resist film 7 as shown in FIG. 7D can be adopted. In this case, application, patterning (exposure and development), etching, and removal of the resist film can be performed by a known method.

  When a chromium-based light-shielding film and / or a chromium-based antireflection film (Cr-based film) is formed on the phase shift multilayer film, the light-shielding film and / or the antireflection film in a region necessary for exposure are removed by etching. Then, after the phase shift film is exposed on the surface, the phase shift film is patterned in the same manner as described above to obtain the phase shift mask 6 in which the chrome-based light-shielding film 3 remains on the outer peripheral side of the substrate as shown in FIG. be able to. In addition, a resist is applied on the chrome-based light-shielding film, patterning is performed, the chrome-based light-shielding film and the phase shift multilayer film are patterned by etching, and only the chromium-based light-shielding film in a region required for exposure is selectively etched. To expose the phase shift pattern on the surface to obtain a phase shift mask.

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited thereto.
(Example 1)
For the formation of the phase shift multilayer film, a DC sputtering apparatus 20 provided with two targets as shown in FIG. 12 was used. MoSi ₄ was used as the target 22M for the molybdenum silicide compound film, and a ZrSi ₅ target was used as the target 22Z for the zirconium silicide compound film.
On a quartz substrate, first, a discharge power of 1000 W was applied to a MoSi ₄ target, and a sputter deposition was performed while rotating the substrate at 30 rpm to provide a first layer film having a thickness of 500 °. As a sputtering gas at this time, a mixed gas of Ar = 20 cm ³ / min, N ₂ = 100 cm ³ / min, and O ₂ = 5 cm ³ / min was introduced into the chamber 21 from the sputtering gas inlet 23. The gas pressure during sputtering was set to be 0.2 Pa.

Next, the discharge of the MoSi ₄ target was stopped, and a discharge power of 1000 W was applied to the ZrSi ₅ target to form a second layer film having a thickness of 100 °. At this time, other film forming conditions were the same as those of the first layer.
As an approximate guide of the Mo concentration of the first layer film and the Zr concentration of the second layer film, comparison is made between the Mo concentration [Mo] in the MoSi ₄ target and the Zr concentration [Zr] in the ZrSi ₅ target. And Under the experimental conditions, [Zr] / [Mo] = 0.833.
After performing the above film formation, the following evaluation was performed.

-Chemical resistance A change in transmittance when immersed in an aqueous solution of ammonia water: hydrogen peroxide solution: water for 1 hour (23 ° C.) at 1: 1: 10 was measured. Those with excellent chemical resistance are considered to have less change in transmittance before and after immersion in the chemical solution. The measurement wavelength was 193 nm. The rate of change in transmittance before and after immersion in the chemical solution was 0.012.
Step of Etch Pattern A resist film 7 is formed on the phase shift multilayer film obtained under the above conditions as shown in FIG. 7A, and the resist film 7 is formed as shown in FIG. Then, as shown in FIG. 7C, the phase shift multilayer film 2 was dry-etched as shown in FIG. 7C, and then the resist film 7 was peeled off as shown in FIG. 7D. A gas containing CF ₄ as a main component was used for dry etching.
The cross section of the obtained pattern was observed, and the step 14 of the etch pattern generated at the interface between the surface film 2s of the phase shift multilayer film 2 and the lower film 2d of the phase shift multilayer film as shown in FIG. There was no problem.

(Example 2)
The same DC sputtering apparatus as in Example 1 was used for forming the phase shift multilayer film. MoSi ₄ was used as a target for the molybdenum silicide compound film, and a ZrSi ₄ target was used as a target for the zirconium silicide compound film.
On a quartz substrate, first, a discharge power of 1000 W was applied to a MoSi ₄ target, and a sputter deposition was performed while rotating the substrate at 30 rpm to provide a first layer film having a thickness of 500 °. As a sputtering gas at this time, a mixed gas of Ar = 20 cm ³ / min, N ₂ = 100 cm ³ / min, and O ₂ = 5 cm ³ / min was introduced. The gas pressure during sputtering was set to be 0.2 Pa.

Next, the discharge of the MoSi ₄ target was stopped, and a discharge power of 1000 W was applied to the ZrSi ₄ target to form a second layer having a thickness of 100 °. At this time, other film forming conditions were the same as those of the first layer.
As a rough guide of the Mo concentration of the first layer film and the Zr concentration of the second layer film, comparison is made between the Mo concentration [Mo] in the MoSi ₄ target and the Zr concentration [Zr] in the ZrSi ₄ target. And Under the experimental conditions, [Zr] / [Mo] = 1.
After performing the above film formation, the following evaluation was performed.

-Chemical resistance In the same manner as in Example 1, the change in transmittance when immersed in an aqueous solution of ammonia water: hydrogen peroxide solution: water at 1: 1: 10 (23 ° C.) for 1 hour was measured. The change rate of the transmittance before and after the immersion in the chemical solution was 0.017.
-Step of Etch Pattern In the same manner as in Example 1, a pattern was formed on the phase shift multilayer film.
Observing the cross section of the obtained pattern and measuring the step 14 of the etch pattern generated at the interface between the surface layer 2s of the phase shift multilayer film 2 and the lower layer film 2d of the phase shift multilayer film as shown in FIG. There was no problem.

(Example 3)
The same DC sputtering apparatus as in Example 1 was used for forming the phase shift multilayer film. MoSi ₄ was used as a target for the molybdenum silicide compound film, and a ZrSi ₃ target was used as a target for the zirconium silicide compound film.
On a quartz substrate, first, a discharge power of 1000 W was applied to a MoSi ₄ target, and a sputter deposition was performed while rotating the substrate at 30 rpm to provide a first layer film having a thickness of 500 °. As a sputtering gas at this time, a mixed gas of Ar = 20 cm ³ / min, N ₂ = 100 cm ³ / min, and O ₂ = 5 cm ³ / min was introduced. The gas pressure during sputtering was set to be 0.2 Pa.

Next, the discharge of the MoSi ₄ target was stopped, and a discharge power of 1000 W was applied to the ZrSi ₃ target to form a second layer having a thickness of 100 °. At this time, other film forming conditions were the same as those of the first layer.
As an approximate guide of the Mo concentration of the first layer film and the Zr concentration of the second layer film, the Mo concentration in the MoSi ₄ target [Mo] and the Zr concentration in the ZrSi ₃ target [Zr] are compared. And Under the experimental conditions, [Zr] / [Mo] = 1.25.
After performing the above film formation, the following evaluation was performed.

-Chemical resistance In the same manner as in Example 1, the change in transmittance when immersed in an aqueous solution of ammonia water: hydrogen peroxide solution: water at 1: 1: 10 (23 ° C.) for 1 hour was measured. The rate of change of the transmittance before and after immersion in the chemical solution was 0.022.
-Step of Etch Pattern In the same manner as in Example 1, a pattern was formed on the phase shift multilayer film.
The cross section of the obtained pattern was observed, and the step 14 of the etch pattern generated at the interface between the surface film 2s of the phase shift multilayer film 2 and the lower film 2d of the phase shift multilayer film as shown in FIG. There was no problem.

(Comparative Example 1)
The same DC sputtering apparatus as in Example 1 was used for forming the phase shift multilayer film. In Comparative Example 1, only MoSi ₄ was used as the target for the molybdenum silicide compound film.
On a quartz substrate, a discharge power of 1000 W was applied to a MoSi ₄ target, and sputter deposition was performed while rotating the substrate at 30 rpm to provide only a first-layer film having a thickness of 500 °. As a sputtering gas at this time, a mixed gas of Ar = 20 cm ³ / min, N ₂ = 100 cm ³ / min, and O ₂ = 5 cm ³ / min was introduced. The gas pressure during sputtering was set to be 0.2 Pa.
After performing the above film formation, the following evaluation was performed.

-Chemical resistance In the same manner as in Example 1, the change in transmittance when immersed in an aqueous solution of ammonia water: hydrogen peroxide solution: water at 1: 1: 10 (23 ° C.) for 1 hour was measured. The rate of change of the transmittance before and after the immersion in the chemical solution was 0.110, which was not a value that indicates sufficient chemical resistance.
-Step of Etch Pattern In the same manner as in Example 1, a pattern was formed on the phase shift multilayer film.
In Comparative Example 1, no particular problematic step was observed because the film was a molybdenum silicide single-layer film.

(Comparative Example 2)
The same DC sputtering apparatus as in Example 1 was used for forming the phase shift multilayer film. MoSi ₄ was used as a molybdenum silicide compound film target, and a MoSi ₁₅ target was used as a molybdenum silicide compound film target for improving chemical resistance.
On a quartz substrate, first, a discharge power of 1000 W was applied to a MoSi ₄ target, and a sputter deposition was performed while rotating the substrate at 30 rpm to provide a first layer film having a thickness of 500 °. As a sputtering gas at this time, a mixed gas of Ar = 20 cm ³ / min, N ₂ = 100 cm ³ / min, and O ₂ = 5 cm ³ / min was introduced. The gas pressure during sputtering was set to be 0.2 Pa.
Next, the discharge of the MoSi ₄ target was stopped, and a discharge power of 1000 W was applied to the MoSi ₁₅ target to form a second layer having a thickness of 100 °. At this time, other film forming conditions were the same as those of the first layer.
After performing the above film formation, the following evaluation was performed.

-Chemical resistance In the same manner as in Example 1, the change in transmittance when immersed in an aqueous solution of ammonia water: hydrogen peroxide solution: water at 1: 1: 10 (23 ° C.) for 1 hour was measured. The rate of change of the transmittance before and after immersion in the chemical solution was 0.014.
-Step of Etch Pattern In the same manner as in Example 1, a pattern was formed on the phase shift multilayer film.
Observing the cross section of the obtained pattern and measuring the step 14 of the etch pattern generated at the interface between the surface layer 2s of the phase shift multilayer film 2 and the lower layer film 2d of the phase shift multilayer film as shown in FIG. It was a large value.

Table 1 summarizes the above results.
As is clear from these results, in a phase shift mask blank in which a phase shift multilayer film composed of at least two layers or more is provided on a substrate, the phase shift multilayer film is formed of a molybdenum silicide compound film and a zirconium silicide compound film. It was confirmed that by forming and using a zirconium silicide compound film as a surface layer film, it becomes possible to obtain a phase shift mask blank and a phase shift mask which are excellent in chemical resistance and have a small step on the side surface of the etch pattern.

  Note that the present invention is not limited to the above embodiment. The above embodiment is merely an example, and any embodiment having substantially the same configuration as the technical idea described in the claims of the present invention and having the same function and effect will be described. It is included in the technical scope of the invention.

It is a figure showing the structure of the phase shift mask blank of the present invention. FIG. 3 is a diagram illustrating a structure of a phase shift mask of the present invention. (A)-(c) is a figure explaining an example of the manufacturing method of the phase shift mask blank of this invention. It is a figure showing the structure of the phase shift mask blank provided with the chrome system light shielding film of the present invention. It is a figure showing the structure of the phase shift mask blank provided with the chrome system light shielding film and the chrome system anti-reflection film of the present invention. It is a figure showing the structure of another phase shift mask blank of the present invention. It is explanatory drawing which showed the manufacturing method of the phase shift mask, (A) is the state which formed the resist film, (B) was the state which patterned the resist film, (C) was the state which performed etching, (D) FIG. 4 is a view showing a state where a resist film is removed. FIG. 4 is a diagram showing a structure of another phase shift mask of the present invention. (A), (B) is a figure explaining the principle of a halftone type phase shift mask, (B) is the elements on larger scale of X part of (A). FIG. 4 is a diagram illustrating a structure of a conventional phase shift mask blank. FIG. 9 is a diagram illustrating a structure of a conventional phase shift mask. It is the schematic of the direct-current sputtering apparatus used in the Example. It is a conceptual diagram which shows the level | step difference which arises on the etch pattern side surface.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 ... board | substrate, 1a ... substrate exposure part, 2 ... phase shift multilayer film, 2 '... phase shift film
2a: phase shifter part, 2s: surface film, 2d: lower film,
2M: molybdenum silicide compound film, 2Z: zirconium silicide compound film,
3: chrome-based light-shielding film, 4, 4 ': chrome-based antireflection film,
5,50 ... Phase shift mask blank, 6,60 ... Phase shift mask,
7: resist film, 14: step,
20: sputtering apparatus, 21: chamber,
22M: molybdenum silicide target,
22Z: zirconium silicide target,
22S: silicon target, 23: sputter gas inlet.

Claims (6)

  A phase shift mask blank, comprising at least a phase shift multilayer film composed of two or more layers on a substrate, wherein the phase shift multilayer film is a film mainly composed of a molybdenum silicide compound and a zirconium silicide compound. A phase shift mask blank, comprising: a film mainly composed of zirconium silicide compound; and a top layer film of the phase shift multilayer film being a film mainly composed of a zirconium silicide compound.   The phase shift according to claim 1, wherein the molybdenum silicide compound is a compound of molybdenum silicide and oxygen and / or nitrogen, and the zirconium silicide compound is a compound of zirconium silicide and oxygen and / or nitrogen. Mask blank.   3. The phase shift mask blank according to claim 1, wherein a chromium-based light-shielding film and / or a chromium-based antireflection film is formed on the phase shift multilayer film.   4. A phase shift mask, wherein a pattern is formed on a phase shift multilayer film of the phase shift mask blank according to claim 1.   A method for manufacturing a phase shift mask blank, comprising at least a step of forming a phase shift multilayer film composed of two or more films on a substrate by sputtering, wherein the sputtering film comprises at least molybdenum silicide as a component. By using a target containing zirconium silicide as a constituent component and a target containing at least oxygen or nitrogen, a molybdenum silicide compound is used as the phase shift multilayer film by changing the power applied to each target. A film containing a zirconium silicide compound as a main component is formed, and a film containing a zirconium silicide compound as a main component is formed as the outermost layer of the phase shift multilayer film. Method for manufacturing phase shift mask blank   A method for manufacturing a phase shift mask, comprising: forming a pattern by a lithography method on a phase shift multilayer film of a phase shift mask blank manufactured by the manufacturing method according to claim 5.

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