KR20040054805A - Halftone phase shift mask blank, halftone phase shift mask, and manufacturing method thereof - Google Patents

Abstract

The present invention includes a light transmitting portion for transmitting exposure light on a transparent substrate, a phase shifter portion for transmitting a portion of the exposure light and shifting a phase of the transmitted light by a predetermined amount, and a phase shifter film for forming the phase shifter portion. And a halftone phase shift mask having optical characteristics such that light transmitted through each of the boundary portions of the phase shifter portion cancels each other, and maintaining and improving the contrast of the exposure pattern boundary portion transferred to the surface of the object to be exposed. It is a halftone type phase shift mask blank used to make. The phase shifter film is composed of a film whose main components are silicon, oxygen and nitrogen, and an etching stopper film formed between the film and the transparent substrate.

Description

Halftone phase shift mask blank, halftone phase shift mask and manufacturing method thereof {HALFTONE PHASE SHIFT MASK BLANK, HALFTONE PHASE SHIFT MASK, AND MANUFACTURING METHOD THEREOF}

Currently, the DRAM (Daynamic Random Access Memory) has a mass production system of 256 Mbit, and will be more highly integrated from Mbit to Gbit in the future. Accordingly, the design rules of integrated circuits are also becoming more and more fine, and it is also a matter of time that fine patterns having a line width (half pitch) of 0.10 mu m or less are required.

As one of means for responding to the miniaturization of a pattern, the resolution of the pattern has been advanced so far by shortening the exposure light source. As a result, KrF excimer laser (248 nm) and ArF excimer laser (193 nm) are mainly used as exposure light sources of the current optical lithography method.

However, shortening the exposure wavelength improves the resolution, but at the same time the depth of focus decreases. This results in an adverse effect that the burden on the design of the optical system including the lens is increased or the process stability is lowered.

In order to cope with such a problem, the phase shift method is used. In the phase shift method, a phase shift mask is used as a mask for transferring a fine pattern.

The phase shift mask is composed of, for example, a phase shifter portion forming a pattern portion on the mask and a non-pattern portion in which the phase shifter portion does not exist. Under such a configuration, by changing the phase of the light passing through both of them by 180 °, the light is caused to interfere with each other at the pattern boundary to improve the contrast of the transferred image.

The phase shift amount? Of light passing through the phase shifter portion depends on the complex refractive index real portion n and the film thickness d of the phase shifter portion, and it is known that the relationship of the following equation (1) is established.

φ = 2πd (n-1) / λ

Is the wavelength of the exposure light. Therefore, to change the phase 180 °, change the film thickness (d).

d = λ / {2 (n-1)}

You can do The increase in the depth of focus for obtaining the required resolution is achieved by such a phase shift mask, thereby making it possible to simultaneously improve the resolution and the applicability of the process without changing the exposure wavelength.

The phase shift mask can be largely classified into a fully transmissive (Levisson type) phase shift mask and a halftone phase shift mask in practical terms depending on the light transmission characteristics of the phase shifter portion forming the mask pattern. The former is a mask having a light transmittance of the phase shifter portion equal to that of the non-pattern portion (light transmission portion) and being almost transparent to the exposure wavelength, and is generally known to be effective for transfer of line and space.

On the other hand, in the latter halftone type, the light transmittance of the phase shifter (light semitransmissive part) is about several to several tens of percent of the non-patterned part (light transmissive part), and it is known that it is effective for creating contact holes or isolation patterns.

Among the halftone phase shift masks, there are a two-layer halftone phase shift mask mainly consisting of a layer for adjusting transmittance and a layer for adjusting phase mainly, and a single-layer halftone phase shift mask having a simple structure and easy manufacturing. .

The single layer type is easy to process and is currently mainstream, and most of the half-tone phase shifters are composed of a single layer film made of MoSiN or MoSiON.

On the other hand, the two-layer type is composed of a combination of a layer mainly controlling the transmittance and a layer mainly controlling the transmittance of the halftone phase shifter, and independently of the spectral characteristics represented by the transmittance and the phase shift amount (phase angle) Can be controlled.

On the other hand, as the LSI pattern becomes smaller, the wavelength of the exposure light source (exposure light wavelength) is shorter from the current KrF excimer laser (248 nm) to ArF excimer laser (193 nm), and in the future, to F ₂ excimer laser (157 nm). The painter is expected to proceed.

In the current halftone phase shift mask, the film design is mainly performed such that the exposure light transmittance of the halftone phase shifter portion is about 6%. However, high transmittance is required for high resolution, and in the future, it is also said that transmittance of 15% or more is required.

With such shortening of wavelength and high transmittance of the exposure light source, the material selection width of the halftone phase shifter that satisfies the predetermined transmittance and phase shift amount tends to be narrowed. In addition, as the transmittance increases, a material having high light transmittance is required. In addition, with the shortening of the exposure light source, a material having high light transmittance is required when viewed at a conventional wavelength. Because of this necessity, there is a problem that the etching selectivity with the quartz substrate is reduced during pattern processing.

In the multilayered halftone phase shifter of two or more layers, the phase difference and the transmittance can be controlled by the combination of the multilayer film or the two-layer film, so that material selection is easy. Moreover, the material which functions as an etching stopper of an upper layer can be selected as a lower layer.

Moreover, the produced phase shift mask needs to reduce the reflectance in exposure light to some extent. In the process of inspecting the pattern appearance, light of a wavelength longer than the exposure light wavelength is usually used as the inspection light wavelength, and inspection using a transmission defect inspection apparatus (for example, KLA 300 series or the like) is usually performed. As a result, when the transmittance of the inspection wavelength (for example, the exposure wavelength is KrF excimer laser (248 nm), the inspection wavelength is 488 nm or 364 nm) becomes too high (for example, 40% or more), the inspection becomes difficult.

In particular, as described above, the short wavelength of the exposure wavelength requires a halftone phase shifter with high light transmittance. However, a material having high light transmittance tends to increase in transmittance with respect to a change in wavelength to the long wavelength side. For this reason, in the single-layer halftone phase shifter, it is more difficult to lower the light transmittance with respect to the inspection light wavelength to a predetermined range.

In addition, in the defect inspection apparatus, an inspection method using transmitted light and reflected light is newly developed. When inspected in this manner, the transmittance at the inspection wavelength may be slightly higher than that when inspected using only transmitted light (for example, 50 to 60%). However, it is necessary to control the reflectance at the inspection wavelength to be a difference (for example, 3% or more) from the transparent substrate.

Under such a situation, by making the halftone phase shifter part into a multilayer of two or more layers, the reflection characteristics and the transmission characteristics of the exposure light and the inspection light can be easily controlled.

As a two-layer halftone type phase shift mask, there exists a halftone phase shifter part of the 2-layer structure of thin Cr and coating glass of Unexamined-Japanese-Patent No. 4 (1992) -140635, for example. (Prior Example 1)

Further, as a halftone phase shifter portion which can be made with the same device and can be etched with the same etchant, a multilayer structure containing the same element as described in Japanese Patent Application Laid-Open No. 6 (1994) -83034 ( For example, there exists a halftone phase shifter part which consists of a two-layer structure of a Si layer and a SiN layer) (conventional example 2).

Further, as a technique for reducing the transmittance with respect to the inspection light wavelength, a single layer film such as MoSiO or MoSiON, which is known as a single-layer halftone phase shifter, is described in Japanese Patent Application Laid-Open No. 7 (1995) -168343. And a two-layer structure including a transmissive film having a small wavelength dependency of transmittance in combination with a single layer film, a desired transmittance can be obtained for both the exposure light (KrF excimer laser) and the inspection light (488 nm). (Prior Example 3).

Moreover, as a phase shifter part of the multilayered structure which pays attention to tantalum silicide type material, it is the upper layer which has tantalum, silicon, and oxygen as a main component of Unexamined-Japanese-Patent No. 2001-174973, and does not contain a silicon which contains tantalum as a main component. There exists a halftone phase shifter part comprised by the lower two-layer structure (conventional example 4).

Moreover, it has a halftone type phase shifter part which consists of the upper layer which has tantalum, silicon, and oxygen as a main component, and the lower layer which has a chromium or chromium tantalum alloy as a main component of Unexamined-Japanese-Patent No. 2001-337436 (formerly Example 5).

However, the above-described conventional example has the following problems.

Usually, on the halftone phase shifter film, it is common to use it as an etching mask layer of a halftone phase shifter film, and to form a light-shielding Cr layer in order to form a light shielding part on a desired place on a mask after that.

In the coated glass / thin Cr layer / glass substrate as in Example 1, a light shielding Cr layer is formed on the coated glass. In this case, a mask pattern having a three-layer structure of a light-shielding Cr layer / coated glass / thin Cr layer, which transfers a resist pattern generally used in pattern processing, is produced, and then the light-shielding Cr layer is selectively selected by conventional wet etching. Is removed.

However, since the light-shielding Cr layer and the thin Cr layer have a common material, the effect on the thin Cr layer in the selective removal process of the light-shielding Cr layer becomes a problem. Specifically, the thin Cr layer may be etched and the pattern may be removed entirely on the same principle as in lift-off. When the thin Cr layer is side etched, the transmittance near the pattern edge is changed.

Next, in the conventional example 2, for example, the Si layer and the SiN layer can be formed into a film continuously using the same Si as a target by the same sputtering apparatus. However, when the SiN layer is formed by reactive sputtering using a sputtering atmosphere containing a Si target and nitrogen, poisoning of the target by reactive sputtering occurs, reproducibility cannot be obtained, and there is a problem in productivity. In addition, when SiN is used, the transmittance is excessively lowered in accordance with the recent shortening of the exposure wavelength.

Next, in the conventional example 3, MoSiO or MoSiON is used as a material of a single | mono layer film (upper layer). However, since the metal is contained, the transmittance is small, which is not suitable for shortening the recent exposure wavelength. In addition, when the metal content is made small, the refractive index becomes small and the film thickness of the halftone phase shifter becomes thick, which is disadvantageous for microfabrication.

In addition, in Example 4 and Example 5, TaSiO is used as an upper layer material. However, since the metal is contained, the transmittance is small, which is not suitable for shortening the exposure wavelength in recent years. In addition, when the metal content is made small, the refractive index becomes small and the film thickness of the halftone phase shifter becomes thick, which is disadvantageous for microfabrication.

Further, in these conventional examples, the lower layer serves as an etching stopper for dry etching with an upper fluorine-based gas, and the lower layer is then etched by dry etching with a chlorine-based gas.

However, in the lower layer which consists of tantalum of the prior art 4, the etching selectivity with respect to the upper fluorine-type dry etching is inadequate. In the chromium tantalum alloy of the conventional example 5, the etching rate by chlorine-type gas is slow and a high precision pattern cannot be obtained.

An object of the present invention is to provide a halftone phase shift mask blank and a halftone phase shift mask having excellent micromachinability during etching for forming a halftone phase shifter.

In addition, the present invention particularly has a high transmittance (transmittance) in the exposure wavelength region of 140 nm to 200 nm, particularly in the vicinity of 157 nm, which is the wavelength of F ₂ excimer laser, and 193 nm, which is the wavelength of ArF excimer laser, especially when the exposure source is shortened. It is an object to provide a halftone phase shift mask blank and a halftone phase shift mask that can be used under 8-30%).

The present invention relates to a halftone phase shift mask blank, a halftone phase shift mask, and a method for manufacturing the same, and is particularly suitable for use in ArF excimer laser (193 nm) and F ₂ excimer laser (157 nm), which are next generation short wavelength exposure light sources. It relates to a phase shift mask blank and the like.

1 is a cross-sectional view of a halftone phase shift mask blank and a halftone phase shift mask according to an embodiment of the present invention.

FIG. 2 is a diagram showing a transmission spectrum of a light semitransmissive portion (phase shifter portion) of samples prepared in Examples 2 and 5. FIG.

3 is a view showing a relationship between etching time and reflected light intensity of samples prepared in Examples 2 and 10;

4 is a schematic view for explaining a processing procedure of each layer of Example 2;

5 is a schematic diagram for explaining a processing procedure of each layer of Example 3. FIG.

6 is a schematic view for explaining a processing procedure of each layer of Comparative Example 2. FIG.

7 is a manufacturing process diagram of a halftone phase shift mask blank and a halftone type halftone phase shift mask according to the eleventh embodiment.

Fig. 8 is a manufacturing process chart of the halftone phase shift mask blank and the halftone type halftone phase shift mask according to the eleventh embodiment (the following figures).

9 is a spectral diagram of optical characteristics of a halftone phase shift mask blank according to the twelfth embodiment;

10 is a spectrum diagram of optical characteristics of a halftone phase shift mask blank according to Example 13. FIG.

11 is a diagram showing a modification of the halftone phase shift mask blank and the halftone phase shift mask according to the embodiment of the present invention.

The present invention is characterized in that in the halftone phase shift mask blank, the phase shifter film is composed of a film whose main components are silicon, oxygen and nitrogen, and an etching stopper film formed between the film and the transparent substrate.

In the present invention, in the halftone phase shifter layer formed on the transparent substrate, the film on the transparent substrate side becomes the lower layer, and the film formed on the lower layer becomes the upper layer.

The inventors of the present invention found that SiN _x has a high resistance to exposure to exposure to exposure to light and chemicals such as cleaning liquids because Si-N bonds densify the matrix of the film, and SiO _x has a relatively high transmittance even on the short wavelength side. Based on the fact that it is possible to pay attention to SiO _x N _y taking advantage of both material systems.

In addition, it was found that, in SiO _x N _y , control of the composition yields a phase shifter film suitable for use in short wavelength exposure light. Then, the halftone phase shifter film has a two-layer structure of a SiO _x N _y film (upper layer) and an etching stopper film (lower layer), in addition to resistance to irradiation of exposure light and resistance to chemicals, a phase having good pattern workability. It has been found that the shifter film can be realized.

Here, the etching stopper film is a function to be able to easily detect the film, or a phase end point of the shifter film etching made of a material having a function for preventing the progression of etching SiO _x N _y film, or a material having all of these features It is made up of.

As a material of an upper layer, it consists of materials which consist substantially of silicon, oxygen, and nitrogen. That is, the upper layer consists of a film whose main components are silicon, oxygen and nitrogen. The material can control desired transmittance and retardation in combination with the lower layer even when the exposure light is shortened in wavelength, and also has high resistance to exposure to exposure light and chemicals such as cleaning liquids. Moreover, since the refractive index can be made relatively large, the film thickness of the whole halftone phase shifter film for obtaining a desired phase difference can be suppressed, and it is excellent in the fine workability of a halftone phase shifter film.

For the upper layer material, the complex refractive index portion n is n In the 1.7 range, and complex refractive index f (k) is k It is preferable to adjust and control to 0.450. This is advantageous in satisfying the optical characteristics as the halftone phase shift mask according to the shortening of the exposure light. Further, F ₂ excimer laser for the k The range of 0.40 is preferred, and 0.07 k The range of 0.35 is more preferable.

0.10 for ArF excimer lasers k The range of 0.45 is preferred. In addition, for F ₂ excimer laser, n A range of 2.0 is preferred, n The range of 2.2 is more preferred. N for ArF excimer lasers A range of 2.0 is preferred, and n The range of 2.5 is more preferable.

In order to obtain the optical properties, the composition range of the member element was 35 to 45 atomic% silicon, 1 to 60 atomic% oxygen, and 5 to 60 atomic% nitrogen. In other words, if the silicon content is more than 45% or the nitrogen content is more than 60%, the light transmittance of the film becomes insufficient. On the contrary, when nitrogen is less than 5% or oxygen is more than 60%, the light transmittance of the film is too high, so that the function as a halftone phase shifter film is lost. In addition, when silicon is less than 35% or nitrogen is more than 60%, the structure of the film becomes very unstable physically and chemically.

In addition, it is preferable from the viewpoint as described above, for the F ₂ excimer laser configured range of silicon 35 to 40 at% of the constituent elements 25 to 60 at.% Oxygen, nitrogen, 5 to 35 at%. Similarly, for ArF excimer laser, the composition range of the above-mentioned elemental elements is preferably 38 to 45 atomic% of silicon, 1 to 40 atomic% of oxygen, and 30 to 60 atomic% of nitrogen. In addition to the above composition, a small amount of impurities (metal, carbon, fluorine, etc.) may be included.

The upper layer according to the present invention uses a target substantially made of silicon, and can be formed by reactive sputtering in a sputtering atmosphere using a rare gas and a reactive gas containing nitrogen and oxygen. The target which consists of silicon substantially obtains a stable target with high water density and purity compared with the case where the mixed target like metal silicide is used. For this reason, there exists an advantage that the particle generation rate of the obtained film | membrane becomes small.

Further, the etching stopper layer is, materials having all of the features, or such a function that enables to easily detect the film, or a phase end point of the shifter film etching made of a material having a function for preventing the progression of etching SiO _x N _y film It is made up of.

A film having a function of inhibiting the progress of etching of the former SiO _x N _y film has a low selectivity to etching of the phase shifter layer, that is, the etching rate with respect to the etching medium used for etching the SiO _x N _y film is SiO _x N _A material that is slower than the _y film, specifically, is a film made of a material whose etching selectivity with respect to the phase shifter film is 0.7 or less, preferably 0.5 or less.

In addition, the etching stopper film which has a function which makes it easy to detect the end point of the etching of the latter phase shifter film, The material of the etching stopper detection light (for example, 680 nm) of a transparent substrate (for example, synthetic quartz substrate) and an etching stopper The difference in reflectance with respect to the film is larger than the difference between the transparent substrate and the SiO _x N _y film.

It is preferable that the material has a higher refractive index (complex refractive index seal) than the SiO _x N _y film and the transparent substrate. Specifically, the film is made of a material whose refractive index difference between the SiO _x N _y film and the wavelength of the etching endpoint detection light is 0.5 or more, preferably 1 or more, and the refractive index difference with the transparent substrate is 0.5 or more, preferably 1 or more. It is a film made of a material.

As an etching stopper layer, it is good that the etching selectivity with respect to a board | substrate is 1.5 or more, Preferably it is 2.0 or more. In other words, if the etching stopper layer cannot be removed, the light transmittance at the light transmitting portion is reduced and the contrast during pattern transfer is reduced. Even if it can remove, if an etching rate is not larger than a board | substrate, a board | substrate may also be etched near the end point of an etching, and processing precision will deteriorate.

In view of the above, suitable materials include one or two or more materials selected from magnesium, aluminum, titanium, vanadium, chromium, yttrium, zirconium, niobium, molybdenum, tin, lanthanum, tantalum, tungsten, silicon, hafnium, or These compounds (oxide, nitride, oxynitride) etc. are mentioned.

It is preferable that the film thickness of an etching stopper film is 10-200 angstroms. In other words, if it is smaller than 10 angstroms, the etching cannot be completely prevented or a significant change in reflectance cannot be detected, so that the pattern processing accuracy may deteriorate.

On the other hand, the expansion of the pattern by the isotropic etching progresses depending on the etching process, but proceeds up to about twice the film thickness at the maximum. Therefore, when processing a pattern line width of 0.1 mu m = 1000 angstroms or less, if the film thickness exceeds 200 angstroms, a dimensional error of 40% or more is caused, which seriously affects the quality of the mask.

Moreover, it is preferable that an etching stopper layer has a function which adjusts a transmittance | permeability. The transmittance | permeability with respect to the exposure wavelength (wavelength 140-200 nm, 157 nm vicinity, or 193 nm vicinity) of the etching stopper layer itself shall be 3-40%. Accordingly, the transmittance of the inspection wavelength longer than the exposure wavelength can be reduced by the etching stopper layer formed under the phase shifter portion (by lamination of other materials) while maintaining the transmittance in the phase shifter portion.

That is, the current mask inspection in the manufacturing process takes a method of measuring the transmitted light intensity using light having a wavelength longer than the exposure wavelength. It is preferable that the light transmittance of the light half excess part (phase shifter part) becomes 40% or less in the range of 200-300 nm of current inspection wavelengths. That is, if it is 40% or more, contrast with a light transmission part will not be obtained and inspection precision will deteriorate. When the etching stopper film is a material having high light shielding function, the material is a film made of one or two or more materials selected from aluminum, titanium, vanadium, chromium, zirconium, niobium, molybdenum, lanthanum, tantalum, tungsten, silicon, and hafnium or These nitrides etc. are mentioned.

Moreover, it is preferable to introduce | transduce the film thickness of such an etching stopper layer into the film thickness sufficiently thinner than a phase shifter part, and the film thickness of 200 angstrom or less is suitable. That is, when it exceeds 200 angstroms, the light transmittance in exposure wavelength is likely to be less than 3%. In this case, the phase angle and transmittance are adjusted in two layers of the SiO _x N _y film and the etching stopper film.

Specifically, the transmittance of the etching stopper itself with respect to the exposure wavelength (wavelength of 140 to 200 nm or around 157 nm or around 193 nm) is 3 to 40%, so that the transmittance when laminated with the SiO _x N _y film is 3 to 40%. It is desirable to adjust. When providing an etching stopper layer, the etching stopper layer exposed to the surface of the part corresponded to a light transmission part should be removable. This is because when the etching stopper layer covers the light transmitting portion, the transmittance of the light transmitting portion is reduced.

An etching stopper film removal method, the etching stopper film when makil made of a material having a function for preventing the progression of etching SiO _x N _y film, it is necessary to use a SiO _x N _y film etching method and other methods. When the etching stopper film is a film made of a material having a function of easily detecting the end point of etching of the phase shifter film, the etching method of the SiO _x N _y film and the etching stopper film may be the same or different.

For etching the phase shifter film made of a SiO _x N _y film, dry etching (RIE: Reactive IonEtching) using a fluorine-based gas such as CHF ₃ , CF ₄ , SF ₆ , C ₂ F ₆ , and a mixed gas thereof can be used. On the other hand, when the etching stopper film is etched away by a method different from the phase shifter film, dry etching using a fluorine-based gas different from that used for removing the phase shifter film, or a chlorine gas such as (Cl ₂ , Cl ₂ + O ₂ ) may be used. Used dry etching or wet etching with an acid or an alkali can be used.

As the etching stopper film which can be removed by the same fluorine-based dry etching as the etching of the phase shifter film made of a SiO _x N _y film, for example, silicon, MoSi _x , TaSi _x , WS _x , CrSi _x , ZrSi _x , HfSi _x and the like are used. Preferred materials are mentioned.

Thus, if the installation can be an etching stopper film in the etching continuously and SiO _x N _y film, the greater the advantage in the process. Further, as an etching stopper film which can be etched by a method different from the etching of a phase shifter film made of SiO _x N _y film, for example, a thin film containing Ta or Ta which can be etched by dry etching of Cl ₂ , such as TaN _x , TaZr _x , TaCr _x , TaHf _x and the like, Zr, Hf, Cr which can be etched by dry etching of Cl ₂ + O ₂ , and the like are mentioned as preferred materials.

Thus, if the installation can be an etching stopper film in the etching continuously and SiO _x N _y film, the greater the advantage in the process. In addition, the etching of the phase shifter film made of SiO _x N _y film may be performed by another method as the etching stopper film, for example, a thin film containing Ta or Ta which can be etched by dry etching of Cl ₂ , such as TaZr _x , TaCr _x , TaHf _x. and the like or, Zr, Hf, Cr, etc. also can be etched by dry etching in Cl + O ₂ to a desired material.

In addition, when the etching stopper film is a film made of a material having a function of preventing the progress of etching of the SiO _x N _y film, and is made of a material having a high transmittance, the transparent substrate and the light half of the halftone phase shift mask of the single layer structure described above are used. It is also possible to provide a structure in which an etching stopper film is provided between the transmission films so as not to remove the etching stopper exposed to the light transmitting part.

The etching stopper layer is particularly effective when oxygen of the SiO _x N _y film is 40 atomic% or more, or when the difference between the transparent substrate and the refractive index is 0.5 or less, preferably 0.3 or less.

In addition, the inventors of the present invention, when the upper layer is a layer that is etched using dry etching with a fluorine-based gas, dry etching with a gas different from the fluorine-based gas (for example, chlorine-based gas) while being resistant to the fluorine-based gas as a lower layer material. The predetermined material which can be etched using was discovered.

Such predetermined materials include, firstly, a single metal selected from the first group consisting of Al, Ga, Hf, Ti, V, and Zr, or a material containing two or more of these metals (including alloys and the like). The first material hereinafter) may be mentioned. The monolithic metal or first material selected from these first groups is a material which is resistant to fluorine-based gas and which can be etched using dry etching with a gas different from the fluorine-based gas (for example, chlorine-based gas).

The monolithic metals or materials selected from these first groups have high etching resistance in dry etching using fluorine-based gas, and dry etching using fluorine-based gas and other gases (for example, chlorine-based gas, bromine-based gas and iodine-based gas). It is a material which can be easily etched.

The lower layer needs resistance to the extent that the effect as an etch stop layer can be obtained with respect to the upper layer in dry etching using a fluorine-based gas, and the etching rate of the lower layer material is the thickness of the lower layer and the etching rate ratio with the upper layer (hereinafter selected). Ratio of 0 to several tens of angstroms / min is preferred. In the lower layer dry etching using the chlorine-based gas, the etching can be removed to an extent that is acceptable in the desired etching process, and it is preferable that the etching rate is 5 times higher than the substrate material, and the etching rate is 10 times higher. The material is more preferred.

In monolithic metals selected from the first group, Hf, Zr and the like are preferable in view of high resistance to chemicals. Al, Ti, V, etc. are preferable from a viewpoint of the ease of preparation of the target for sputtering.

Secondly, as the predetermined material, the first group is formed of one metal selected from a second group consisting of Cr, Ge, Pd, Si, Ta, Nb, Sb, Pt, Au, Po, Mo, and W. The material which added at least 1 sort (s) chosen from Al, Ga, Hf, Ti, V, and Zr (The mixture contains a mixture etc. besides alloy. Hereafter, it is called 2nd material) is mentioned. These materials exhibit sufficient resistance to fluorine-based gases by adding a metal selected from the first group to a metal selected from the second group, and furthermore, gases other than fluorine-based gas (e.g., chlorine-based gas, bromine-based gas and iodine-based gas). It is a material which can be etched by dry etching using a gas). That is, it is a material which can achieve the same effect as a 1st material.

Here, the metals quoted in the second group (except Cr) are less resistant to fluorine-based gases as compared to the metals quoted in the first group. When the metal selected from the first group is added, the resistance to the fluorine-based gas is improved compared to the case where no metal is added. Furthermore, when the metal selected from the first group is added, the desired resistance to the fluorine-based gas is sufficiently expressed. It is. In addition, Cr has the same resistance to fluorine-based gas as the metals cited in the first group.

In addition, the metal of the second group is a material whose etching rate for the chlorine-based gas is equal to that of the metal of the first group or slightly deteriorated so that it can be supplemented by adding the first group. As the metal cited in the first group is a material which can be easily etched with respect to chlorine-based gas, as described above, the material in which the metal cited in the first group is added to the metal cited in the second group is, for example, chlorine-based. It becomes the material which maintained or improved the etching characteristic with respect to gas.

As described above, the present inventors have found that by adding a small amount of the metal selected from the first group to the metal selected from the second group, the resistance to fluorine-based gas is significantly improved while the etching characteristics for the chlorine-based gas are maintained. The amount of adding the metal selected from the first group to the metal selected from the second group is 2% or more. This is because if the amount is less than that, the properties of the additive material do not appear sufficiently, and as described above, the effect of improving the resistance to the fluorine-based gas cannot be sufficiently obtained.

Third, examples of the predetermined material include a material in which nitrogen and / or carbon are contained in the metal, the first material, or the second material of the monolithic material. It is preferable that nitrogen and / or carbon are contained in the range which does not impair desired characteristic.

Here, the fluorine-based gas includes, for example, C _x F _y (for example, CF ₄ , C ₂ F ₆ ), CHF ₃ , a mixed gas thereof, or O ₂ , rare gas (He, Ar, Xe) as an additive gas, and the like. Can be mentioned.

As gases other than fluorine-based gas, halogen-based gases other than fluorine (chlorine-based, bromine-based, iodine-based or a mixture thereof) can be used. Examples of the chlorine-based gas include Cl ₂ , BCl ₃ , HCl, mixed gas thereof, and those containing rare gas (He, Ar, Xe) as additive gas.

Examples of the bromine gas include Br ₂ , HBr, mixed gas thereof, and those containing rare gas (He, Ar, Xe) as additive gas. Examples of the iodine-based gas include I ₂ , HI, mixed gas thereof, and those containing rare gas (He, Ar, Xe) as additive gas.

Here, as the gas different from the fluorine-based gas, it is preferable to use a chlorine-based gas because the etching rate can be faster than that of the bromine-based gas or the iodine-based gas. Moreover, the gas containing both fluorine and gases other than fluorine can also be used. In this case, there is an advantage in that the ratio of the excitable species to the active species in the plasma is large.

When there are many fluorine excitation species, it is defined as fluorine-based gas. When there are many excitation species (for example, chlorine) of gas other than a fluorine-type gas, it is prescribed | regulated as gas other than the fluorine-type gas (for example, chlorine gas). With respect to the case containing fluorine as a halogen element other than that in the gas composition of the monolith (e.g., ClF _3, etc.) with a fluorine gas.

As gas other than fluorine-type gas, it is preferable that oxygen is not added as addition gas. This is because, when oxygen is added, the lowering of the etching rate is considered by surface oxidation. In addition, for example, the etching gas Cl ₂ + O ₂ commonly used for etching of Cr has a complicated reaction and is liable to generate an etch distribution. Therefore, dry etching with a single gas such as Cl ₂ may result in a highly accurate pattern. It is preferable to obtain.

Next, the operation of each layer that satisfies the above requirements will be described.

Since the lower layer is resistant to the fluorine-based gas, even if the upper layer is dry-etched with the fluorine-based gas and the surface of the lower layer is exposed, the film reduction of the lower layer is slow. For this reason, the over-etching time of an upper layer can fully be set in consideration of the removal of the residual film of the upper layer which arises from the etching distribution which arises from the difference of the roughness of a pattern, etc .. As a result, formation of a pattern faithful to the mask pattern becomes possible and improvement of the dimensional accuracy is expected.

Since the lower layer is a material which can be etched using dry etching with a fluorine-based gas and another gas (for example, chlorine-based gas) (having a certain etching rate with respect to the chlorine-based gas), the lower layer is dried using, for example, chlorine-based gas. I etch it. Even when the surface of the transparent substrate is exposed, there is almost no cavity in the surface of the transparent substrate. Accordingly, variations in the in-plane retardation due to phase difference fluctuations due to the cavity of the substrate surface layer and etching imbalance can be avoided, and high phase difference controllability can be obtained. This is because the quartz substrate, which is often used as the substrate for the phase shift mask, has a smaller etching rate for dry etching of underlayer removal than the underlayer material.

The higher the etching rate of the lower layer with respect to the chlorine-based gas, the more preferable. Although it is somewhat different depending on the CD dimensional accuracy request value and etching conditions, the etching rate is preferably 2500 angstroms / min or more, 3000 angstroms / min or more and 4000 angstroms / mim or more. Specifically, the lower layer of the phase shift mask is usually 100 angstroms or less. Since the lower layer has a high etching rate, etching of the lower layer is completed in a few seconds. This is because the over-etching time is also very short, and the etching rate (cavity amount) is very small at 6 angstroms / sec for 1 second even if the etching rate is 360 angstroms / min.

In addition, unlike the structure of the light-shielding Cr layer / coating glass / thin Cr layer / transparent substrate described in the prior art, in the configuration of the light-shielding Cr layer / upper layer / lower layer / transparent substrate of the present invention, the light-shielding Cr layer and the lower layer material are different materials. Since it is made, it becomes possible to selectively handle in the removal process of a light-shielding Cr layer. Such a removal process is not limited to the wet process which mainly uses the cerium acetate diammonium liquid generally used, It can respond also by using dry etching. That is, irrespective of whether it is wet etching or dry etching, it is possible to avoid the adverse effects of the underlying layer being etched in the selective removal process of the light shielding Cr layer. That is, suitability for such a process.

In forming the lower layer and the upper layer, it is possible to contribute to the improvement of pattern accuracy by forming the film structure such that the film structure is formed to have an amorphous structure or a very small grain boundary. This means that when these film structures are columnar or crystalline, unevenness (roughness) occurs on the sidewalls of the pattern during etching, but if these film structures are amorphous or have very small grain boundaries, This is because the pattern side wall at the time of etching processing becomes substantially flat (approximately straight line).

In addition, when these film structures have a columnar structure or a crystal structure, film stress may occur and become a problem. However, it is easy to control the film stress if these film structures are amorphous or have very small grain boundaries.

In addition, the upper layer of the phase shifter film is SiO _x , SiN _x , SiO _x N _y , SiC _x , SiC _x N _y , SiC _x O _y N ₂ or metals such as M (Mo: Ta, W, Cr, Zr). , One or two or more kinds of Hf), preferably made of M / (Si + H) × 100 of 10 atomic% or less, which can be easily processed by dry etching with a fluorine-based gas. It is preferable because it has high resistance to dry etching using a chlorine-based gas. In addition, when the upper layer is made of such a material, even if the exposure wavelength is shortened by the ArF excimer laser (193 nm) or the F ₂ excimer laser (157 nm), the predetermined transmittance and phase shift amount can be satisfied to meet the shorter wavelength. There is a number.

The phase shift mask blank has, for example, a structure consisting of a SiO _x and SiO _x N _y layer / lower layer (layer having the above etching characteristics) / transparent substrate made of the predetermined material. Under such a configuration, the SiO _x and SiO _x N _x layers are patterned by dry etching using a fluorine-based gas, and the parts touching the lower layer by dry etching using a chlorine-based gas, so that damage to the base can be reduced. do.

By using the blank of such a structure, an optical characteristic can be controlled even in the generation to which short wavelength advanced, and a phase shift effect is acquired. Specifically, the phase shift amount is mainly controlled by the thickness, composition, etc. of the upper layers SiO _x and SiO _x N _y layers, and the transmittance is mainly controlled by the thickness of the lower layer made of the predetermined material. As a result, the optical characteristics can be controlled.

Further, by processing the lower layer by dry etching using a chlorine-based gas, damage to the transparent substrate serving as the base can be avoided. Since the change of the phase shift amount by the cavity of the transparent substrate can be avoided and the above-described optical characteristics can be controlled, a predetermined phase shift effect can be obtained.

In the present invention, a light shielding Cr layer is formed on the phase shift mask blank, a resist pattern is formed on the light shielding Cr layer to form a light shielding Cr layer pattern, and a phase shifter is formed by using only a resist pattern, a light shielding Cr pattern, or a light shielding Cr pattern as a mask. It is preferable to etch the film. After the etching of the phase shifter film, the light shielding Cr pattern leaves the light shielding band portion of the non-transfer region of the phase shift mask. Or, in addition, the desired region is removed except the alignment mark forming portion inside or outside the transfer region or near the boundary of the pattern. The light shielding Cr layer may be a single layer or a multilayer film containing Cr, Cr, or the like containing oxygen, carbon, nitrogen, or the like.

In the present invention, the reflectance with respect to the inspection light can be adjusted by making the refractive index of the upper layer film at the inspection wavelength smaller than that of the lower layer. In addition, in the exposure wavelength, by making the refractive index of the upper layer film smaller than the refractive index of the lower layer film, the reflectance with respect to the exposure light can also be adjusted to be less than or equal to the required value.

Specifically, the transmittance of the exposure light is 3 to 20%, preferably 6 to 20%, and the exposure light reflectance is 30%, preferably 20%, which is preferable for transferring the pattern. In addition, the inspection light transmittance of 40% or less is preferable for performing defect inspection using the transmitted light of the mask. The inspection light transmittance of 60% or less and the inspection light reflectance of 12% or more are preferable for defect inspection using the transmitted light and the reflected light of the mask.

As the exposure light when using the halftone phase shift mask of the present invention, particularly the exposure wavelength range of 140nm ~ 200nm, specifically, an F ₂ near the wavelength of 157nm of the excimer laser and ArF wavelength of 193nm near the excimer laser can be used . It is also possible to produce high-transmittance products in which the halftone phase shifter is set at high transmittance (transmittance of 8 to 30%).

In addition, in this invention, a membrane design is made so that an upper layer may become a layer (phase adjustment layer) which mainly functions to adjust a phase shift amount, and a lower layer becomes a layer (transmittance adjustment layer) which mainly functions to adjust transmittance.

That is, when the phase shift amount φ; deg of the exposure light of wavelength λ passing through the upper layer (phase adjustment layer) is φ, the film thickness d of the phase adjustment layer is

d = (φ / 360) × λ / (n-1)

Is displayed. Here, n is the refractive index of the phase adjustment layer with respect to light of wavelength (lambda).

When the phase shift amount Φ of the halftone phase shifter portion is the phase shift amount of the lower layer (transmittance adjustment layer) as φ ',

Φ = φ + φ '= 180 °

It needs to be designed to be. The value of φ 'is approximately -20 ° φ ' It is in the range of 20 °. That is, if it is outside the above-mentioned range, the film thickness of the lower layer becomes too thick and the transmittance of the exposure light cannot be increased. Therefore, the film thickness d of the upper layer is

d 0.56 × λ / (n-1)

Is designed in the range of.

Specifically, the film thickness of the lower layer can be 1 to 20 nm, more preferably 1 to 15 nm. As a result, the layer film thickness of the halftone phase shifter film can be suppressed to 120 nm or less, more preferably 100 nm or less.

The amount of phase shift of the halftone phase shifter film is ideally 180 °, but may be in the range of 180 ° ± 5 ° in practical use.

In addition, a synthetic quartz substrate or the like can be used as the transparent substrate of the present invention. In particular, an F-doped synthetic quartz substrate, a calcium fluoride substrate, or the like can be used when the F ₂ excimer laser is used as the exposure light.

The material of the lower layer is particularly preferably made of a material substantially composed of tantalum and hafnium or made of a material substantially composed of silicon and hafnium. The underlayer material is resistant to the fluorine-based dry etching gas and can be removed by the chlorine-based dry etching gas. Thereby, as a processing method (etching method) of a halftone phase shift film, an upper layer can be etched by dry etching using a fluorine gas, and a lower layer can be performed by dry etching using a chlorine gas.

Specifically, tantalum or silicon is a material that can be etched by dry etching using a chlorine-based gas that does not damage a transparent substrate even in a single body. However, the resistance to dry etching using the fluorine-based gas of the upper layer is not so excellent.

On the other hand, a single hafnium is a material that is excellent in resistance to dry etching using an fluorine-based gas of the upper layer and can be etched by dry etching using a chlorine-based gas. By adding hafnium to tantalum or silicon, the resistance to dry etching using a fluorine-based gas can be improved than before addition, and the material is maintained or improved for chlorine-based gas. The addition amount of hafnium to tantalum or silicon is preferably 2 atomic% or more from the viewpoint of obtaining resistance to fluorine-based dry etching gas.

When the lower layer is made of a material consisting substantially of tantalum and hafnium, or silicon and hafnium, the amount of hafnium added in the lower layer is preferably 50 atomic% or less. The reason is that the light semitransmissive film made of tantalum or silicon has little difference between the light transmittance at the exposure wavelength and the transmittance at the inspection wavelength. Alternatively, the transmittance at the inspection wavelength is greater than the transmittance at the exposure wavelength, and is suitable for designing the optical characteristics (transmittance and / or reflectance of the exposure light and the inspection light), so that the optical characteristics can be easily designed by sufficiently including tantalum or silicon. Because it can.

In the halftone phase shift mask blank and the halftone phase shift mask of the present invention, heat treatment or laser annealing may be performed after film formation of the halftone phase shifter film. By heat treatment, effects such as relaxation of film stress, resistance to chemicals and resistance to irradiation, and fine adjustment of transmittance can be obtained. Heat processing temperature is 200 degreeC or more, and it is preferable that it is 380 degreeC or more.

In the present invention, a light shielding film mainly composed of chromium can be formed on the halftone phase shifter film. The light shielding film can be used as an etching mask layer of the halftone phase shifter film and then selectively removed to form a light shielding portion at a desired place or region on the halftone phase shift mask. Examples of the light-shielding film containing chromium as a main component include a film having a single layer or a multi layer structure (including a film having a continuous composition gradient) containing oxygen, nitrogen, carbon, fluorine, etc. in addition to chromium and chromium. In addition, it is preferable to form an antireflection film (antireflection in exposure wavelength) containing oxygen in the surface layer portion.

When a light shielding film containing chromium as a main component is formed on the halftone phase shifter film of the halftone phase shift mask, a light shielding film formed as a light shielding band can be formed on the outer circumference of the transfer region. Alternatively, a light shielding film formed at the place where the mark is formed may be formed to increase the contrast such as the alignment mark. Alternatively, in order to obtain a phase shift effect and reduce side lobe light, a light shielding film formed in a region except for the vicinity of the boundary of the light semitransmissive portion can be formed.

Moreover, this invention includes the aspect except the limitation of a top-down relationship, and a use limitation based on the dry etching characteristic of the upper layer and the lower layer mentioned above. This makes it possible to utilize as a laminate material for dry etching (laminate material before dry etching processing) in fields such as application to an etching mask material and use as an etching stopper material.

The demand for a material having excellent dry etching characteristics is not limited to the photomask using the above-described phase shift, but an etching stopper layer (etching stop layer) for protecting the base layer, thinning due to high selectivity and finer pattern Is applicable to a wide range of applications, such as the application to the etching mask material required.

In the above aspect, the second layer material is a material having high etching resistance in dry etching using a fluorine-based gas and which can be easily etched under the conditions using a chlorine-based gas (hereinafter, a material exhibiting a predetermined action). Such a second layer material includes any one or more of Al, Ga, Hf, Ti, V, and Zr, and the film obtained by adding these elements to a film composed of these monolithic elements and other metals is obtained. to be. The addition amount with respect to other metal shall be 2% or more. It is because the characteristic of an additive material does not fully appear by the addition amount below that, and the said predetermined | prescribed action is not acquired by etching. The other metal is a material which can be etched with respect to the chlorine-based gas. Examples of other metals include Cr, Ge, Pd, Si, Ta, Nb, Sb, Pt, Au, Po, Mo, W and the like.

By using these materials, it becomes possible to etch with a high selectivity using the difference of the dry etching characteristic according to a gas kind. This effect also contributes to the thinning of the constituent layer (eg, thinning of the etching mask layer) and leads to an improvement in the precision of the fine pattern.

Furthermore, in forming the first layer material and the second layer material, it is possible to contribute to the improvement of pattern precision by forming the film structure such that the film structure becomes an amorphous structure or a structure having a very small grain boundary. This means that when these film structures are columnar or crystalline, unevenness (roughness) occurs on the pattern side walls during etching, but if these film structures are amorphous or have very small grain boundaries, This is because the pattern side wall at the time of etching processing becomes substantially flat (approximately straight line). In addition, when these film structures have a columnar structure or a crystal structure, film stress may occur and become a problem. However, if these film structures are amorphous or have very small grain boundaries, film stress can be easily controlled.

The upper layer part of a board | substrate is also included in the 1st layer of the above-mentioned aspect. That is, the case where a 2nd layer is used as an etching mask layer and a cavity pattern is formed in a board | substrate surface layer part is included. Moreover, the laminated body of the said aspect contains the laminated body of a 2nd layer and a board | substrate (an upper layer part corresponds to a 1st layer).

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

Fig. 1 (1) shows a cross section of the halftone phase shift mask blank according to the embodiment and comparative example, and Fig. 1 (2) shows a cross section of the halftone phase shift mask according to the embodiment and comparative example. .

In Fig. 1 (1), the halftone phase shift mask blank 1 is a halftone phase shifter film 5 composed of a transparent substrate 2 and a lower layer 3 thereon and an upper layer 4 formed just above the lower layer. )

In Fig. 1 (2), the halftone phase shift mask 1 'is a halftone phase composed of an upper layer portion 4' formed on the transparent substrate 2 and immediately above the lower layer portion 3 'and the lower layer portion 3'. It is comprised by the shifter part 5 '. Under such a configuration, a mask pattern 8 including a light transflective portion 6 in which the halftone phase shifter is formed and a light transmissive portion 7 in which the halftone phase shifter is not formed are formed. The halftone phase shifter film 5 and the halftone phase shifter film 5 'have a desired transmittance with respect to the exposure light, and the phase shift angle is approximately 180 degrees. Moreover, it is designed so that the transmittance | permeability in an inspection wavelength or a transmittance | permeability and a reflectance may become a desired range.

(Examples 1-8)

Examples 1 to 8 are examples of halftone phase shift masks corresponding to F ₂ excimer laser exposure, all of which use a synthetic quartz substrate as a substrate, and an etching stopper layer is provided between the substrate and the SiO _x N _y layer. .

(Film formation)

First, a layer A consisting of an etching stopper layer and a layer B composed of SiO _x N _y is laminated on the synthetic quartz substrate in order. In the present Example, it produced by the sputtering method. The conditions, such as the basic composition of layers A and B of a two-layer film, the kind of target and sputter gas, and the film thickness of each layer are as showing in Table 1 for every Example. In addition, the film thickness of each layer A and B is adjusted using Formula (1) mentioned above so that the sum total of the phase shift amount of each layer may be 180 degrees at wavelength 157nm.

(Optical characteristics)

The transmittance of the produced two-layer film was measured using a vacuum ultraviolet photometer. The transmittance at the wavelength of 157 nm of the F ₂ excimer laser was as shown in Table 2, and even when an etching stopper layer was provided, it was necessary as a halftone phase shift mask. A sufficient light transmittance in the range of 3-40% was obtained.

target Board Gas ratio (%) Film thickness (nm) argon nitrogen Oxygen Example 1 Layer A: Al ₂ O ₃ Synthetic Quartz 100.0 0.00 0.00 15 Layer B: Si 40.0 59.00 1.00 75 Example 2 Layer A: Ta Synthetic Quartz 40.0 60.00 0.00 10 Layer B: Si 40.0 59.00 1.00 72 Example 3 Layer A: Ta-Zr Synthetic Quartz 100.0 0.00 0.00 8 Layer B: Si 40.0 59.00 1.00 78 Example 4 Layer A: Ta-Hf Synthetic Quartz 100.0 0.00 0.00 8 Layer B: Si 40.0 59.00 1.00 78 Example 5 Layer A: Zr Synthetic Quartz 100.0 0.00 0.00 5 Layer B: Si 40.0 59.00 1.00 80 Example 6 Layer A: Hf Synthetic Quartz 100.0 0.00 0.00 5 Layer B: Si 40.0 59.00 1.00 80 Example 7 Layer A: Si Synthetic Quartz 100.0 0.00 0.00 4 Layer B: Si 40.0 59.00 1.00 80 Example 8 Layer A: MoSi _x Synthetic Quartz 100.0 0.00 0.00 8 Layer B: Si 10.0 60.00 30.00 86

% Light transmittance (157 nm) Example 1 13.1 Example 2 7.6. Example 3 6.6 Example 4 5.8 Example 5 15.7 Example 6 14.2 Example 7 9.8 Example 8 10.1

In addition, the transmission spectrum of Example 2 is shown in FIG. Since F ₂ test wavelength of the excimer laser for exposure halftone phase shift mask, but is around 250nm, the transmittance in this range, it is less than 40%, it can be expected to acquire a sufficient inspection accuracy. Moreover, also about Example 1, 3-7, the transmittance | permeability before and after 250 nm became 40% or less.

In Examples 1-6, a resist is apply | coated on the produced 2-layer film, and a resist pattern is formed through an exposure and image development process. Thereafter, the upper layer (B; SiO _x N _y film) of the two-layer film is etched by the dry etching method using the resist pattern as a mask. In the present embodiment, CF ₄ gas was used, and the etching time was set to 30% longer than the time capable of roughly etching the film thickness of the SiO _x N _y layer. As a result, the SiO _x N _y film was patterned based on the resist pattern, and the progress of etching was stopped in the underlying etching stopper film.

Table 3 shows the etching rates of the synthetic quartz substrate, the layer A, and the layer B (SiO _x N _y ) of the present embodiment obtained through separate experiments.

CF ₄ etch rate (µs / min) Selection ratio (A / B) Selection ratio (to board) Quartz substrate 118.83 Layer B (SiO _x N _y ) 148.7 1.25 Layer A (AlO _x ) ND ^* 1 <<0.1 <<0.1 Layer A (TaN _x ) 15 0.101 0.13 Layer A (Ta-Zr) 10 0.067 0.08 Layer A (Ta-Hf) 20 0.134 0.17 Layer A (Zr) N.D. <<0.1 <<0.1 Layer A (Hf) 8 0.054 0.07

[ ^* 1: ND (not detected); indicates that it is too small to measure]

With respect to the layer B, the etching rate of the layer A is reduced to 1/5 or less, confirming that the layer A of Examples 1 and 2 is an etching stopper film "having a function of preventing the progress of etching of the SiO _x N _y film". Can be.

The layer A exposed on the surface was then removed by etching. As an etchant, when persulfuric acid was used in Example 4 and Cl ₂ gas was used in Examples 2 to 6, good pattern shapes were all obtained. Table 4 shows the etching rates of the synthetic quartz substrate and the layer A obtained through separate experiments. The etching rate of the layer A with respect to the synthetic quartz substrate is 5 times or more, and it can be confirmed that the layer A of Examples 1 and 2 is a "removable" layer.

Cl ₂ etch rate (µs / min) Selection ratio (to board) Persulfate Etching Rate (Å / min) Selection ratio (to board) Quartz substrate 269.8 0 Layer B (SiO _x N _y ) 415.9 1.54 0 Layer A (AlO _x ) 101 0.37 Dissolve instantly >> 10 Layer A (TaN _x ) 2039.6 7.56 Layer A (Ta-Zr) 4020 14.90 Layer A (Ta-Hf) 3000 11.12 Layer A (Zr) 3300 12.23 Layer A (Hf) 2800 10.38

In Examples 7 and 8, a resist is applied onto the produced two-layer film, and a resist pattern is formed through an exposure and development process. Thereafter, using the resist pattern as a mask, the upper layer B (SiO _x N _y ) and the lower layer A of the two-layer film are etched with CF ₄ gas. The relationship between the etching time at this time and the reflected light intensity of the portion to be etched with respect to the light of wavelength 678 nm was structured. As for the seventh embodiment, it was confirmed that the reflected light intensity suddenly decreased at a certain time.

When the etching was stopped at that point, a good pattern shape based on the resist pattern was obtained for both the layers A and B. That is, it can be confirmed that the layer A of Example 10 is an "etching stopper film" having a function of making it possible to easily detect the end point of etching of the SiO _x N _y film and a "removable" film. In addition, the refractive index (complex refractive index real part) of the synthetic quartz substrate, the layer A, and the layer B in wavelength 678nm is 1.47, 4.70, and 1.67, respectively. As described above, when the refractive index of the layer B is greater than or equal to that of the synthetic quartz substrate and the layer A, the end point is easily detected because a sudden change in the reflected light intensity as shown in FIG. 3 can be obtained before and after the etching of the layer B. This change in the reflected light intensity was similarly obtained in the case of Example 8.

In addition, the relationship between the etching time and the reflected light intensity was also structured and shown in FIG. Even in the case of a SiON layer monolayer, the end point can be detected, but in Example 7, the end point becomes clearer.

(Example 9)

In this example, the underlayer material was examined. Table 5 shows TaZr _x (a material containing Ta and Zr, and does not indicate the composition ratio of Ta and Zr when dry-etched using fluorine-based and chlorine-based gases. Table 6 shows the results of confirming the etching characteristics of TaAl and TaHf when dry etching using fluorine-based and chlorine-based gases. That is, in the present Example, mainly confirmed the dry etching characteristic of the film which mainly uses Ta and added the material (Al, Hf, Zr) considered to be related to the effect of this case.

Zr content rate (%) Etching gas Etch Rate (µs / min) Selection ratio (/ QZ) TaZr _x Cl ₂ 4020 11.2 Zr 100 Cl ₂ 3370 9.4 QZ 0 Cl ₂ 360 - TaZr _x 1.8 C ₂ F ₆ 40 0.3 TaZr _x 2.6 C ₂ F ₆ 40 0.3 TaZr _x 4.3 C ₂ F ₆ 10 0.1 Zr 100 C ₂ F ₆ 7 0.1 Qz 0 C ₂ F ₆ 120 -

Each film material is formed into a film by sputtering. For material addition, a metal piece of the target material was placed on the Ta target to form a film. The presence or absence of the addition into the film was confirmed by X-ray photoelectron spectroscopy (XPS). The gas shown in Table 6 was used for dry etching. In this embodiment, etching was performed by high density plasma using an inductively coupled plasma source.

Etching gas Etch Rate (µs / min) Selection ratio (/ QZ) TaAl Cl ₂ 2880 11.5 TaHf Cl ₂ 2980 11.0 QZ Cl ₂ 260 - TaAl C ₂ F ₆ 70 0.6 TaHf C ₂ F ₆ 20 0.2 QZ C ₂ F ₆ 110 -

As a result of the experiment, it was confirmed that by adding a small amount of the material (Al, Hf, Zr) of the present case, the resistance to fluorine-based gas was improved while maintaining the chlorine-based characteristics. In addition, the monolithic Zr metal film according to the present invention has a high etching resistance (low etching rate) in dry etching using a fluorine-based gas, and a material which can be easily etched (high etching rate) in dry etching using a chlorine-based gas. Was confirmed.

(Reference Example 1)

In order to confirm the addition effect of Example 9, as a comparative example, the dry etching characteristic regarding the Ta metal film of the single body which did not add the said material was confirmed. As shown in Table 7, the monolithic Ta metal film had insufficient selectivity with a quartz substrate with respect to fluorine-based gas. In addition, the etching conditions of this comparative example are performed according to Example 9.

Etching gas Etch Rate (µs / min) Selection ratio (/ QZ) Ta Cl ₂ 2900 8.1 QZ Cl ₂ 360 - Ta C ₂ F ₆ 110 0.9 QZ C ₂ F ₆ 120 -

(Example 10)

In this embodiment, the SiON layer was processed using the Zr film as an etching mask.

The film structure was made resist / Zr / SiON (FIG. 4 (a)), and each layer formed on the Si substrate was processed to confirm the effect as an etching mask material. In the present Example, the film thickness of each layer was set to Zr layer 200 angstrom and SiON layer 800 angstrom. After the Zr layer was processed with chlorine gas using the resist pattern as a mask (FIG. 4B), the residual film of the Zr layer was measured after the SiON layer was processed. It was found to exhibit etch resistance.

(Example 11)

In this embodiment, the fabrication of a photomask having a phase shift effect was attempted. Here, in consideration of the selectivity between materials, the micromachining of the blank which consists of a structure of a SiON / TaZr / QZ board | substrate was performed.

The two-layer film on the QZ substrate was formed by forming an SiON layer of about 800 angstroms and a TaZr layer of about 60 angstroms using an RF magnetron sputter. For pattern processing (or shading Cr layer formation), a film of about 500 angstroms of Cr is formed on the SiON layer, and then ZEP resist for electron beam is applied, and is subjected to electron beam lithography and development process, and has a width of 0.5 μm. Was formed (FIG. 5 (a)).

Here, the film thickness of each layer was set in consideration of the phase difference of the mask transmitted light.

Based on the resist pattern, Cr processing was performed using a mixed gas of chlorine + oxygen (oxygen consumption of about 20%) (FIG. 5B).

Thereafter, the SiON layer was processed using a C ₂ F ₆ gas (FIG. 5C). Thereafter, the TaZr layer is etched with chlorine gas (Fig. 5 (d)), and the Cr layer (including the resist film) is removed (or leaving a light shielding portion) by a wet process mainly composed of cerium acetate ammonium acetate. Selectively removed) (FIG. 5 (e)) to form the desired test pattern.

For pattern processing, a high density plasma etching apparatus using an inductively coupled plasma source was used. As a result of observing the cross section of the pattern shape after processing using SEM (scanning electron microscope), it was confirmed that a good pattern with little cavity for the QZ substrate was formed.

Moreover, when the same pattern observation was attempted about the sample which stopped processing by the processing of a SiON layer, it confirmed that there was almost no film reduction of a TaZr layer. By providing the over etching time which considered distribution in predetermined dry etching time, pattern formation without the residual film of a SiON layer was implement | achieved. Also, side etching of the TaZr layer due to the removal of the Cr layer was not found.

(Reference Example 2)

In this comparative example, the TaZr layer of Example 10 was made TaN whose etching resistance by fluorine-type gas was close to a SiON layer. The same process as in Example 3 was carried out except that the material on the QZ substrate was changed. In addition, the TaN film was formed by reactive sputtering with a mixed gas of argon + nitrogen. Specifically, Cr processing was performed based on the resist pattern (FIGS. 6A and 6B), and then the SiON layer was processed using C ₂ F ₆ gas (FIG. 6C). . Thereafter, the TaN layer is etched with chlorine gas (FIG. 6 (d)), and the Cr layer (including the resist film) is removed by a wet process mainly composed of cerium acetate ammonium acetate (FIG. 6E). )) A predetermined test pattern was formed.

As in Example 10, as a result of forming a 0.5 µm test pattern, the pattern shape could be processed to exhibit a good shape as described above, but the cavity for the QZ substrate serving as the base was confirmed. Moreover, the etching rate of the TaN film by fluorine-type gas was almost equivalent to QZ.

(Example 12)

In this comparative example, it processed similarly except having changed the TaZr layer described in Example 10 into an Hf layer and a Zr layer.

A fine pattern was formed by the same treatment and the pattern shape was observed by SEM. As a result, it was confirmed that the same pattern as in Example 3 was formed. As for the damage to the QZ substrate, almost no difference was observed, and it was confirmed that good pattern formation was achieved.

Examples 12 to 14, 17 and Reference Example 3-5 is a F ₂ excimer laser (wavelength: 157nm) to use, and the phase shift mask blank created using light with a wavelength of 257nm as the inspection light, and phase shift mask with exposure light. Examples 15 and 16 are phase shift mask blanks and phase shift masks produced using ArF excimer laser (wavelength 193 nm) as exposure light and light having a wavelength of 364 nm as inspection light.

Next, the manufacturing process of the present invention will be described with reference to FIGS. 7 and 8.

First, on the synthetic quartz-type transparent substrate 2, targets of the composition shown in Table 1 (but, for reference examples 3 and 5, respectively) and rare gas (argon gas) are used as sputtering gas. The lower layer 3 was formed into a film using the DC magnetron sputtering apparatus.

Next, the upper layer 4 was formed into a film by using a DC magnetron sputtering apparatus immediately above the lower layer 3 by a reactive sputtering method using Si as a target and Ar, O ₂ , N ₂ as a sputtering gas ( (1) of FIG. 7).

Next, the halftone phase shift mask blank obtained above was heat-treated at 400 ° C. for 1 hour.

Next, a light shielding film 9 containing chromium as a main component and an electron beam lithography resist 10 were laminated in this order on the two-layer film (Fig. 7 (2)). Then, after pattern lithography on the resist with an electron beam, development and baking were performed by dipping to form a resist pattern 10 '(Fig. 7 (3)).

Subsequently, using the resist pattern as a mask, the light shielding band film pattern 9 'was formed by dry etching with Cl ₂ + O ₂ gas. Further, the gas was changed to form a pattern of the halftone phase shifter portion. At this time, CH ₄ + O ₂ was used for etching the upper layer 4, and Cl ₂ gas was used for etching the lower layer 3 (FIG. 7 (4)). However, in Comparative Example 3, since the lower layer was also etched with CH ₄ + O ₂ , etching with Cl ₂ gas was not performed.

Next, the resist on the formed pattern is peeled off (Fig. 8 (1)), and the resist 11 is applied to the entire surface again (Fig. 8 (2)), followed by a laser lithography and developing process. The resist pattern 11 'was formed (FIG. 8 (3)). Then, the light shielding band 12 was formed in the non-transfer region except for the transfer region I by wet etching. Next, the resist pattern was peeled off to obtain a halftone phase shift mask (Fig. 8 (4)).

The transparent substrate material, the composition of the upper layer, the film thickness, the optical characteristics of the exposure light and the inspection light, the etching characteristics, and the like are shown in Tables 8 to 11. In addition, the composition of the lower layer is substantially the same as the composition of the target.

Transparent substrate Upper layer material Upper layer thickness Underlayer Materials Lower layer thickness Exposure wavelength (nm) Exposure wavelength transmittance (%) Exposure wavelength reflectance (%) Inspection wavelength (nm) Inspection Wavelength Transmittance (%) Inspection wavelength reflectance (%) Example 12 F-doped synthetic quartz SiON① 790 Ta-Hf① 100 157 6.20 15.60 257 19.91 32.79 Example 13 CaF ₂ SiON① 800 Ta-Hf① 65 157 9.14 13.55 257 32.39 24.78 Example 14 F-doped synthetic quartz SiON① 810 Ta-Hf② 35 157 14.0 12.00 257 49.30 16.80 Example 15 Synthetic Quartz SiON② 740 Ta-Hf① 75 193 15.1 17.00 364 30.40 21.50 Example 16 Synthetic Quartz SiON④ 960 Hf-Si 100 193 15.83 18.58 364 19.6 38.89 Example 17 CaF ₂ SiON③ 920 Hf-Si 40 157 11.35 9.28 257 46.58 17.83 Reference Example 3 F-doped synthetic quartz SiON④ 770 Ta 60 157 7.33 14.37 257 35.4 24.06 Reference Example 4 F-doped synthetic quartz SiON③ 807 TaCr 80 157 6.30 18.20 257 29.40 25.13 Reference Example 5 F-doped synthetic quartz SiON④ 790 Si 40 157 9.76 11.95 257 43.4 16.93

157nm 193 nm Composition (atomic%) SiON① n k n k Si O N 2.00 0.20 - - 36 48 16 SiON② - - 2.22 0.18 40 27 33 SiON③ 2.05 0.22 - - 36 46 18 SiON④ 2.17 0.30 2.05 0.10 38 38 24

Ta Hf Si Cr Zr Ta-Hf① 90 10 Ta-Hf② 80 20 Hf-Si 17 83 Ta-Cr 96 4

Etch selectivity of lower layer to upper layer (SF ₆ + He) Etch selectivity of the underlying layer to the substrate (Cl ₂ ) Example 12 0.25 > 5 Example 13 0.25 > 5 Example 14 0.08 > 5 Example 15 0.25 > 5 Example 16 0.17 > 5 Example 17 0.17 > 5 Reference Example 3 0.67 > 5 Reference Example 4 0.25 2.50 Reference Example 5 8.08 -

9 and 10 show transmittance and reflectance curves for the wavelengths of Examples 12 and 13, respectively. In Examples 12 and 13, the transmittance with respect to the exposure light (F ₂ excimer laser) was realized near a standard product (6%) and a high transmittance product (around 9%), respectively. The reflectance of the exposure light was low to satisfy the required range (20% or less). In addition, the transmittance of the inspection light was also lower than the upper limit of the required value (40% or less) to sufficiently cope with the inspection.

In addition, in Example 14, high transmittance (around 15%) with respect to exposure light (F ₂ excimer laser) is realized. The reflectance of the exposure wavelength was low to satisfy the required range (20% or less). In addition, the transmittance of the inspection wavelength was slightly high. However, since it satisfies the required values (transmittance of 60% or less and reflectance of 10% or more) for inspection using the transmitted light and the reflected light, it was possible to sufficiently cope with the inspection using the transmitted light and the reflected light.

In Example 15, the exposure rate (around 15%) was realized. The reflectance of the exposure wavelength was low to satisfy the required range (20% or less). In addition, the transmittance of the inspection light was also lower than the upper limit of the required value (40% or less) to sufficiently cope with the inspection.

In addition, in Example 16 and Example 17, the material of a lower layer was made into HfSi instead of TaHf of Examples 12-15. Example 16 was realized the exposing light (ArF excimer laser) and the transmittance (15% vicinity), Example 17 has high transmittance product (near 11%) of the exposing light (F ₂ excimer laser) for. The reflectance of the exposure wavelength was low to satisfy the required range (30% or less). In addition, the transmittance of the inspection light was also lower than the upper limit of the required value (40% or less) to sufficiently cope with the inspection.

Further, in Examples 12 to 17, the etching selectivity with respect to SF ₆ + He dry etching gas is small with respect to the upper layer in the lower layer. Moreover, the lower layer has sufficient resistance to the etching of the upper layer, and the lower layer has a large etching selectivity with respect to the Cl ₂ dry etching gas with respect to the transparent substrate. As a result, since there is little damage to the transparent substrate at the time of removing the lower layer, it is possible to form a halftone phase shift mask having a very good cross-sectional shape and extremely suppressing a change in optical characteristics due to overetching of the transparent substrate.

On the other hand, Reference Example 3 and Reference Example 5 are examples of the case where the lower layer materials are tantalum and silicon of a single body not containing hafnium, respectively. In these comparative examples, the lower layer has a high etching selectivity with respect to the CH ₄ + O ₂ dry etching gas with respect to the upper layer. In addition, when the upper layer is dry-etched using a fluorine-based gas, even if the lower layer surface is exposed, film reduction of the lower layer is quick. As a result, it is difficult to set a sufficient over-etching time in consideration of the removal of the residual film of the upper layer generated due to the etching distribution caused by the difference in the roughness of the pattern and the like.

In other words, if it is not sufficiently overetched, a good cross-sectional pattern cannot be formed, and if it is sufficiently overetched, the lower layer is also etched and the transparent substrate is also deeply dug to change the optical characteristics.

In Comparative Example 1, since the upper layer was not sufficiently overetched, a good cross-sectional pattern was not obtained as a result. Comparative Example 3 In the lower layer CH ₄ + O ₂ etching gas for the dry etching selection ratio is very large with respect to the upper layer. As a result of sufficiently overetching the upper layer, the transparent substrate was also deeply dug and the amount of phase shift was changed.

In addition, in Comparative Example 2, since the etching selectivity with respect to the Cl ₂ dry etching gas was small, the damage to the substrate at the time of removing the lower layer was large and the optical properties were changed.

As another example in which a light shielding film is formed on the halftone phase shifter portion of the halftone type phase shift mask, as shown in FIG. 11, the light shielding layer 13 is disposed in a desired region except for the vicinity of the boundary between the light semitransmissive portion 6 and the light transmissive portion 7. ) Is formed. By forming the light shielding film 13 in this manner, the phase shift effect can be obtained and the side lobe light can be reduced. Since the influence of side lobe light is concerned when the halftone phase shifter portion has a high transmittance, this structure is particularly effective in the case of a high transmittance product (the transmittance of the halftone phase shifter portion is 8 to 30%).

According to the present invention, it is possible to obtain a halftone phase shift mask blank and a halftone phase shift mask excellent in micromachinability at the time of etching for forming a halftone phase shifter portion.

In addition, the micromachinability at the time of etching for forming a halftone phase shifter part is excellent.

In particular, when the exposure light source is shortened, especially in the exposure wavelength region of 140 nm to 200 nm, a high-transmittance product (transmittance of 8 to 30%) near 157 nm, which is the wavelength of the F ₂ excimer laser, and 193 nm, which is the wavelength of the ArF excimer laser, is also used. Can be used

As a result, it is possible to transfer a high-precision transfer pattern by using the halftone phase shift mask of the present invention.

Claims (29)

A light transmitting portion for transmitting the exposure light, a phase shifter portion for transmitting a portion of the exposure light and shifting a phase of the transmitted light by a predetermined amount, and a phase shifter film for forming the phase shifter portion, Halftone phases having optical characteristics such that light transmitted through each of the light transmitting portion and the phase shifter portion boundary cancel each other, and maintaining and improving the contrast of the exposure pattern boundary portion transferred to the surface of the object to be exposed. In the halftone phase shift mask blank used for manufacturing a shift mask, A halftone phase shift mask blank, characterized in that the phase shifter film is composed of a film whose main components are silicon, oxygen, and nitrogen, and an etching stopper film formed between the film and the transparent substrate. The method of claim 1, And the etching stopper film has a function of adjusting transmittance. The method according to claim 1 or 2, And the etching stopper film is a material which can be etched with an etching medium different from that of the film whose silicon, oxygen and nitrogen are the main components. The method according to claim 1 or 2, And the etching stopper film is a material which can be etched with the same etching medium as that of the film whose silicon, oxygen and nitrogen are the main components. The method according to any one of claims 1 to 4, A halftone phase shift mask blank, wherein the phase shift mask is used in an exposure light wavelength range of 140 nm to 200 nm. The method of claim 3, The membranes of which silicon, oxygen and nitrogen are the major constituents each contain 30 to 45% silicon, 1 to 60% oxygen and 5 to 60% nitrogen in atomic percentages, each of which contains at least 90 of the total composition constituting the film. Halftone phase shift mask blank characterized by occupying more than%. The film in which the silicon, oxygen, and nitrogen are the main components is formed by using a reactive sputtering method using an inert gas, oxygen gas, and nitrogen gas as a sputtering gas, with the ratio of oxygen in the sputtering gas being 0.2 to 30%. A method for producing the halftone phase shift mask blank according to claim 3. A transparent substrate having a light transmitting portion for transmitting exposure light, a phase shifter portion for transmitting a portion of the exposure light and shifting a phase of the transmitted light by a predetermined amount, and a phase shifter film for forming the phase shifter portion by etching processing, The halftone phase has optical characteristics such that light transmitted through each of the light transmitting portion and the phase shifter boundary is canceled with each other, and maintains and improves the contrast of the exposure pattern boundary transferred to the surface of the object to be exposed. In the halftone phase shift mask blank used for manufacturing a shift mask, The phase shifter film has a first layer and a second layer sequentially formed on the transparent substrate, The first layer and the second layer can be continuously etched with the same etching medium, The second layer is a material that is difficult or impossible to detect the etching end point for the transparent substrate, The first layer is a halftone phase shift mask blank, characterized in that the material is substantially capable of detecting the etching end point for the transparent substrate. The method of claim 8, The difference in refractive index in the etching endpoint detection light between the second layer and the transparent substrate is 0.5 or less, A halftone phase shift mask blank, wherein the difference in refractive index in the etching end point detection light between the first layer and the transparent substrate is greater than the difference in refractive index in the etching end point detection light between the second layer and the transparent substrate. The method according to claim 8 or 9, The phase shifter film has a two-layer structure of a first layer and a second layer sequentially formed on a transparent substrate, The first layer is mainly a layer for adjusting the transmittance, The second layer is a halftone phase shift mask blank, characterized in that the layer is mainly for adjusting the phase. The method according to claim 8 or 9, The first layer is made of one kind of material selected from Si, MSix (M or Mo, Ta, W, Cr, Zr, Hf, or two or more), The second layer is composed of SiO _x , SiO _x N _y or (M: Mo, Ta, W, Cr, Zr, Hf, one or two or more), and M / (Si + M) × 100 is 10 A halftone phase shift mask blank comprising a material contained in an atomic% or less range. A light transmitting portion for transmitting the exposure light, a phase shifter portion for transmitting a portion of the exposure light and shifting a phase of the transmitted light by a predetermined amount, and a phase shifter film for forming the phase shifter portion, The halftone phase has optical characteristics such that light transmitted through each of the light transmitting portion and the phase shifter boundary is canceled with each other, and maintains and improves the contrast of the exposure pattern boundary transferred to the surface of the object to be exposed. In the halftone phase shift mask blank used for manufacturing a shift mask, The phase shifter film is formed between an upper layer etched by dry etching using a fluorine-based gas and between the upper layer and the transparent substrate and is resistant to the fluorine-based gas and etched by dry etching using a gas different from the fluorine-based gas. At least the lower layer which can be provided, The material of the lower layer is made of a single metal selected from the first group consisting of Al, Ga, Hf, Ti, V and Zr or a material containing two or more of these metals (first material), Alternatively, the material of the lower layer is selected from the first group on one metal selected from the second group consisting of Cr, Ge, Pd, Si, Ta, Nb, Sb, Pt, Au, Po, Mo, and W. It is made of a material (second material) to which at least one kind is added, Or the lower layer material consists of the metal of the said monolith, the said 1st material, or the said 2nd material containing nitrogen and / or carbon, The halftone type phase shift mask blank characterized by the above-mentioned. The method of claim 12, The material of the upper layer is selected from SiO _x , SiN _x , SiO _x N _y , SiC _x , SiC _x N _y , SiC _x O _y or a material containing a metal therein. Etching the upper layer by dry etching using a fluorine-based gas using a desired resist pattern as a mask; Then etching the lower layer by dry etching using a chlorine-based gas, The method of manufacturing a phase shift mask using the halftone type phase shift mask blank of Claim 12 or 13 which has at least the process of removing the said resist pattern. It is manufactured using the method of Claim 14. The halftone type phase shift mask characterized by the above-mentioned. A light transmitting portion for transmitting the exposure light, a phase shifter portion for transmitting a portion of the exposure light and shifting a phase of the transmitted light by a predetermined amount, and a phase shifter film for forming the phase shifter portion, The halftone phase has optical characteristics such that light transmitted through each of the light transmitting portion and the phase shifter boundary is canceled with each other, and maintains and improves the contrast of the exposure pattern boundary transferred to the surface of the object to be exposed. In the halftone phase shift mask blank used for manufacturing a shift mask, A halftone phase shift mask blank, wherein said halftone phase shifter film is composed of an upper layer made of a material substantially made of silicon, oxygen, and nitrogen, and a lower layer made of a material made substantially of tantalum and hafnium. A light transmitting portion for transmitting the exposure light, a phase shifter portion for transmitting a portion of the exposure light and shifting a phase of the transmitted light by a predetermined amount, and a phase shifter film for forming the phase shifter portion, The halftone phase has optical characteristics such that light transmitted through each of the light transmitting portion and the phase shifter boundary is canceled with each other, and maintains and improves the contrast of the exposure pattern boundary transferred to the surface of the object to be exposed. In the halftone phase shift mask blank used for manufacturing a shift mask, A halftone phase shift mask blank, wherein said halftone phase shifter film is composed of an upper layer made of a material substantially made of silicon, oxygen, and nitrogen, and a lower layer made of a material made substantially of silicon and hafnium. The method according to claim 16 or 17, A halftone phase shift mask blank, wherein the content of hafnium in the lower layer is 2 to 50 atomic% or more. The method according to claim 16 or 17, wherein The halftone phase shift mask blank, wherein the upper layer, which is substantially composed of silicon, oxygen, and nitrogen, contains 35 to 45% silicon, 1 to 60% oxygen, and 5 to 60% nitrogen in atomic percentages, respectively. The method according to any one of claims 1, 8, 11, 16, 17, A halftone phase shift mask blank, wherein a light shielding film containing chromium as a main component is formed on the phase shifter film. The halftone phase shifter film of the halftone phase shift mask blank according to claim 16 or 17 is etched to form a mask pattern comprising a light transmitting portion and a light semitransmissive portion on a transparent substrate. Shift mask. The halftone phase shifter etching process of Claim 21 including the halftone phase shifter film etching process of etching the said upper layer by dry etching using a fluorine-type gas, and etching the lower layer by dry etching using a chlorine-based gas. How to make a mask. Half having the mask pattern which consists of a light transmission part and a phase shifter part obtained by the patterning process which selectively removes the phase shifter film in any one of Claims 1, 8, 11, 16, 17 so that a predetermined | prescribed pattern may be obtained. Tone phase shift mask. The pattern transfer method characterized by transferring a pattern using the halftone type phase shift mask of Claim 23. Regardless of the vertical relationship between the laminates, at least a first layer that can be processed by dry etching using a fluorine-based gas and a second layer that can be processed by dry etching using a chlorine-based gas and which are resistant to the fluorine-based gas are at least. In the laminate having, The material of the second layer is made of a single metal selected from the first group consisting of Al, Ga, Hf, Ti, V and Zr or a material containing two or more of these metals (first material), Alternatively, in the first group, the material of the second layer is one metal selected from the second group consisting of Cr, Ge, Pd, Si, Ta, Nb, Sb, Pt, Au, Po, Mo, and W. Consists of a material (second material) to which at least one selected is added, or Or the material of the said second layer consists of the metal of the said monolith, the said 1st material, or the said 2nd material containing nitrogen and / or carbon. The method of claim 25, And the material of the first layer is selected from SiO _x , SiN _x , SiO _x N _y , SiC _x , SiC _x N _y , SiC _x O _y or a material containing a metal therein. The method of claim 25 or 26, The second layer is formed on the first layer, And the second layer is used as an etching mask layer of the first layer. The method of claim 25 or 26, The second layer is formed below the first layer, And the second layer is used as an etching stopper of the first layer. Regardless of the vertical relationship between the laminates, at least a first layer that can be processed by dry etching using a fluorine-based gas and a second layer that can be processed by dry etching using a chlorine-based gas and which are resistant to the fluorine-based gas are at least. In the pattern formation method which forms by having a pattern which has a pattern which has a dry etching using the fluorine-type gas of a said 1st layer, and a dry etching using the chlorine-based gas of a said 2nd layer according to a lamination order, The material of the second layer is made of a single metal selected from the first group consisting of Al, Ga, Hf, Ti, V and Zr or a material containing two or more of these metals (first material), Alternatively, the material of the second layer is selected from the first group on one metal selected from the second group consisting of Cr, Ge, Pd, Si, Ta, Nb, Sb, Pt, Au, Po, Mo and W. Made of a material (second material) added at least one Or the material of the second layer is made of a metal of the monolith, a material containing nitrogen and / or carbon in the first material or the second material.