WO2018181891A1

WO2018181891A1 - Phase shift mask blank, phase shift mask and manufacturing method for phase shift mask

Info

Publication number: WO2018181891A1
Application number: PCT/JP2018/013591
Authority: WO
Inventors: 洋介小嶋
Original assignee: 凸版印刷株式会社
Priority date: 2017-03-31
Filing date: 2018-03-30
Publication date: 2018-10-04
Also published as: JPWO2018181891A1; TW201901282A; SG11201907839RA; TWI778039B; KR102553992B1; KR20190133006A; JP6965920B2

Abstract

The purpose of the present invention is to obtain a phase shift mask with an improved size, wherein an undercut does not occur in a lower layer light-blocking film when the phase shift mask is fabricated. This phase shift mask blank is formed by stacking, on a substrate transparent to an exposure wavelength, a phase shift film having resistance to oxygen-containing chlorine-based etching (Cl/O system) and non-oxygen containing chlorine-based etching (Cl system), and capable of being etched by fluorine-based etching (F system), a light-blocking film having resistance to oxygen-containing chlorine-based etching (Cl/O system), and capable of being etched by non-oxygen containing chlorine-based etching (Cl system), and an etching mask film having resistance to fluorine-based etching (F system) and non-oxygen containing chlorine-based etching (Cl system), and capable of being etched by oxygen-containing chlorine-based etching (Cl/O system), and does not have an etching stopper layer between the phase shift film and the substrate.

Description

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

The present invention relates to a phase shift mask blank, a phase shift mask, and a method for manufacturing a phase shift mask, and more particularly to semiconductor integrated circuits, CCD (charge coupled device), LCD (liquid crystal display device) color filters, magnetic heads, and the like. The present invention relates to a phase shift mask used for manufacturing.

In recent years, with the miniaturization of semiconductor elements, high resolution is also required for projection exposure. Therefore, in the photomask field, a phase shift method has been developed as a technique for improving the resolution of a transfer pattern. The principle of the phase shift method is that the phase of the transmitted light that has passed through the phase shift section adjacent to the opening is adjusted so that the phase of the transmitted light that has passed through the opening is reversed. The light intensity is weakened (phase shift effect), and as a result, the resolution of the transfer pattern is improved. Photomasks using this principle are collectively called phase shift masks.

The most common phase shift mask blank used for the phase shift mask has a structure in which a phase shift film and a light shielding film are sequentially laminated on a transparent substrate such as a glass substrate. The thickness and composition of the phase shift film are adjusted so that the desired phase difference and transmittance are obtained. When the phase difference is 175 to 180 degrees and the transmittance is 5% to 7%, the film thickness is 60 nm to 80 nm. The mainstream is a single-layer film or a multi-layer film of MoSi-based material. Further, the film thickness and the composition of the light shielding film are adjusted so that the OD value (optical density) combined with the phase shift film becomes a desired value, and the OD value combined with the above phase shift film is 2.8. In the above case, the mainstream is a single layer film or a multilayer film of a chromium-based material having a film thickness of 40 nm to 60 nm.

As a pattern formation method of the phase shift mask, a resist film is formed on the light shielding film of the phase shift mask blank, a pattern is drawn on the resist film by a laser beam or an electron beam, and this is developed to form a resist pattern. The light shielding film is etched using the resist pattern as a mask to form a light shielding film pattern, the phase shift film is etched using the light shielding film pattern as a mask, and the resist film and the light shielding film are further removed to form the phase shift film pattern. The method of forming is common.

For phase shift masks that require highly accurate pattern formation, dry etching using gas plasma is the mainstream for etching. Oxygen-containing chlorine-based etching (Cl / O-based) is mainly used for dry etching of a chromium-based light shielding film, and fluorine-based etching (F-based) is mainly used for dry-etching a phase shift film of a MoSi-based material.

On the other hand, with the miniaturization of semiconductor elements, there is a demand for a technique for finely forming a photomask pattern as an original. In particular, the assist pattern for assisting the transfer of the main pattern of the photomask needs to be formed smaller than the main pattern so as not to be transferred onto the wafer during exposure. Assist pattern dimensions for generations of 28 nm or less of logic devices or 30 nm or less of memory devices are required to have a resolution of 60 nm or less.

One of the effective means for improving the resolution of the photomask pattern is to make the resist film thinner. By reducing the aspect ratio (film thickness / width) of the resist film, it is possible to reduce the collapse of the resist pattern and the defect defect during development.

In the phase shift mask, the resist film has been thinned in order to improve the pattern resolution. However, since the resist film is also damaged when the light shielding film having a film thickness of 40 nm to 60 nm is dry-etched, there is a limit to reducing the thickness of the resist film in consideration of the resistance at the time of etching the light shielding film.

Therefore, a phase shift mask blank in which an etching mask film is formed on a light shielding film has been proposed (Patent Document 1 and Patent Document 2). The etching mask film is mainly composed of MoSiN or SiON, which are silicon compounds, in order to obtain sufficient resistance against the light shielding film etching of the underlying chromium-based material. Also, the film thickness is mainly 3 nm to 30 nm, which is thinner than the light shielding film, so that it is possible to suppress the damage of the resist during dry etching more than the light shielding film, and the resist film can be further thinned.

When producing a phase shift mask using this phase shift mask blank with an etching mask film, the dimensions of the etching mask film and the light shielding film are not the same, and an undercut may occur in the lower light shielding film. This is because the etching mask film made of a silicon compound and processed by fluorine etching (F system) and the light shielding film made of a chromium material and processed by oxygen-containing chlorine etching (Cl / O system) are etched in the lateral direction. This is because the dimension of the line pattern is smaller in the light shielding film that is easier to proceed. The amount of undercut of the light shielding film is generally adjusted by dry etching of the light shielding film, but since the amount of etching progressed in the horizontal direction varies depending on the width and area of the pattern region to be etched, in all patterns It is very difficult to remove the undercut of the light shielding film.

As an indispensable process for producing a phase shift mask using this phase shift mask blank with an etching mask film, both the etching mask film and the phase shift film are processed by fluorine-based etching (F system). There is a step of removing the etching mask film at the same time. In this process, when the above-described undercut of the light-shielding film occurs, the dimension of the phase shift film is determined by the etching mask film in the initial stage of etching of the phase shift film, but the thin etching mask film is in the middle. After disappearance of the phase shift film, the dimension of the phase shift film is determined by the exposed light shielding film of the lower layer. That is, since the dimension of the phase shift film changes before and after the disappearance of the etching mask film, a step is generated in the phase shift film, and a uniform dimension cannot be obtained.

Further, there is a phase shift mask blank in which an etching mask film and a part of a light shielding film are formed using the same chromium-based material. In such a phase shift mask blank, when the etching mask film is subjected to an etching process by oxygen-containing chlorine-based etching (Cl / O system), an influence such as undercut occurs in the light-shielding film, or the light-shielding film is oxygenated. If an etching process is performed using the chlorine-containing etching (Cl / O system), the etching mask film is also removed at the same time, which makes it difficult to process.

Also, the silicon compound constituting the etching mask film has poor adhesion to the resist film than the chromium-based material. Therefore, even if the resist film is thinned by the etching mask film, the resist pattern may fall down due to the deterioration of the adhesion to the resist film.

In addition, dry etching of the phase shift film requires control of the etching shape of the phase shift film and the depth of the transparent substrate in the opening, so that only conditions suitable for simultaneous removal of the etching mask film cannot be selected. This causes a residue (removal residue) of the etching mask film and the underlying light shielding film. Furthermore, the residue of the etching mask film can be removed only by fluorine etching (F system), and the phase shift film and the transparent substrate are damaged at the same time. Therefore, this residue cannot be corrected by dry etching.

JP 2005-62884 A International Publication No. 2004/090635

The present invention has been made in view of the above problems, is easy to correct for defects, achieves both improved resolution and dimensional improvement of the pattern of the phase shift mask, suppresses residues of the etching mask film and the light shielding film, and etches. It is an object of the present invention to provide a phase shift mask blank, a phase shift mask, and a method of manufacturing the phase shift mask that enable dry etching correction of the residue of the mask film and the light shielding film.

A phase shift mask blank according to an aspect of the present invention is a phase shift mask blank in which a phase shift film, a light shielding film, and an etching mask film are stacked in this order on a substrate transparent to an exposure wavelength. The phase shift film is resistant to oxygen-containing chlorine-based etching (Cl / O-based) and non-oxygen-containing chlorine-based etching (Cl-based), and can be etched by fluorine-based etching (F-based). The light-shielding film is resistant to oxygen-containing chlorine-based etching (Cl / O-based) and can be etched by non-oxygen-containing chlorine-based etching (Cl-based), and the etching mask film is made of fluorine. Resistant to non-oxygen-containing chlorine-based etching (Cl-based) and oxygen-containing chlorine-based etching (Cl / O-based) No etching stopper layer between the substrate and the phase shift film, characterized in that.

A phase shift mask blank according to an aspect of the present invention is a phase in which a phase shift film, a lower light shielding film, an upper light shielding film, and an etching mask film are laminated in this order on a substrate transparent to the exposure wavelength. A shift mask blank, wherein the phase shift film is resistant to oxygen-containing chlorine-based etching (Cl / O-based), non-oxygen-containing chlorine-based etching (Cl-based), and oxygen-based etching (O-based). In addition, the lower light-shielding film is resistant to fluorine etching (F system) and non-oxygen-containing chlorine etching (Cl system), and can be etched by fluorine etching (F system). The upper light shielding film is resistant to oxygen-containing chlorine-based etching (Cl / O-based), and fluorine-based etching (F-based) and non-acidic. The etching mask film can be etched by both or any of the chlorine-containing etching (Cl-based), and the etching mask film is fluorine-based etching (F-based), non-oxygen-containing chlorine-based etching (Cl-based), and oxygen-based etching. It is resistant to (O-based) and can be etched by oxygen-containing chlorine-based etching (Cl / O-based).

Further, it is preferable that the lower light-shielding film has a film thickness of 2 nm or more and 30 nm or less and is formed of ruthenium alone or a ruthenium compound having a ruthenium content of 50 atomic% or more.

A phase shift mask according to one embodiment of the present invention is a phase shift mask in which a plurality of films including a phase shift film, a light shielding film, and an etching mask film are stacked in this order on a substrate transparent to an exposure wavelength. A blank phase shift mask having a circuit pattern formed by selectively removing a part of the film, wherein the phase shift film comprises oxygen-containing chlorine-based etching (Cl / O-based) and non-oxygen It is resistant to chlorine-containing etching (Cl-based) and can be etched by fluorine-based etching (F-based), and the light-shielding film is resistant to oxygen-containing chlorine-based etching (Cl / O-based). It has resistance and can be etched by non-oxygen-containing chlorine-based etching (Cl-based), and the etching mask film is composed of fluorine-based etching (F-based) and non-oxygen-containing chlorine-based etching (Cl-based). Resistant to a, and is etchable in an oxygen-containing chlorine-based etch (Cl / O system), no etching stopper layer between the phase shift film and the substrate, characterized in that

In the phase shift mask according to one embodiment of the present invention, a phase shift film, a lower light shielding film, an upper light shielding film, and an etching mask film are stacked in this order on a substrate transparent to the exposure wavelength. A phase shift mask in which a circuit pattern is formed by selectively removing a part of the film of the phase shift mask blank, wherein the phase shift film is oxygen-containing chlorine-based etching (Cl / O-based) It is resistant to non-oxygen-containing chlorine-based etching (Cl-based) and oxygen-based etching (O-based), and can be etched by fluorine-based etching (F-based). Resistant to etching (F-based) and non-oxygen-containing chlorine-based etching (Cl-based), and can be etched by oxygen-based etching (O-based). It has resistance to etching (Cl / O system) and can be etched by fluorine etching (F system) and / or non-oxygen-containing chlorine system etching (Cl system). The mask film has resistance to fluorine-based etching (F-based), non-oxygen-containing chlorine-based etching (Cl-based), and oxygen-based etching (O-based), and oxygen-containing chlorine-based etching (Cl / O-based). It is possible to etch with

A method of manufacturing a phase shift mask using a phase shift mask blank according to an embodiment of the present invention includes a step of forming a resist pattern on the etching mask film and oxygen-containing chlorine-based etching (Cl / O-based). Forming a pattern on the etching mask film, and forming a pattern on the light-shielding film by non-oxygen-containing chlorine-based etching (Cl-based) and / or fluorine-based etching (F-based). A step of forming a pattern on the phase shift film by fluorine-based etching (F-based), and an oxygen-containing chlorine-based etching (Cl / O-based) from the pattern formed on the light-shielding film. A non-oxygen-containing chlorine-based etching (Cl-based) or non-oxygen-containing chlorine-based etch from the pattern formed on the phase shift film. Characterized in that it comprises a, and removing the light shielding film at both ring (Cl based) and fluorine-based etching (F based).

A method of manufacturing a phase shift mask using a phase shift mask blank according to an embodiment of the present invention includes a step of forming a resist pattern on the etching mask film and oxygen-containing chlorine-based etching (Cl / O-based). Forming a pattern on the etching mask film, and forming a pattern on the upper light-shielding film by both or one of non-oxygen-containing chlorine-based etching (Cl-based) and fluorine-based etching (F-based). Forming a pattern on the lower light-shielding film by oxygen-based etching (O-based), forming a pattern on the phase-shift film by fluorine-based etching (F-based), and forming on the upper light-shielding film Removing the etching mask film from the formed pattern by oxygen-containing chlorine-based etching (Cl / O system), and a non-oxygen-containing chlorine-based etch (Cl-based) and / or fluorine-based etching (F-based) or at least one of them, the step of removing the upper light-shielding film, and the oxygen-based etching (O-based) from the pattern formed on the phase shift film And removing the lower light shielding film at

In the phase shift mask blank according to an embodiment of the present invention, the film made of the chromium-based material that is easily etched in the lateral direction and processed by the oxygen-containing chlorine-based etching (Cl / O-based) is the uppermost layer as the etching mask film. Only exists. Accordingly, an undercut does not occur in the lower light shielding film, the lower light shielding film or the antireflection film below it, and a phase shift mask with improved dimensions can be obtained.

In addition, since a thin film thickness is sufficient for this etching mask film, it is possible to improve the dimension by shortening the etching time and the resolution by reducing the resist thickness. Furthermore, since the chromium-based material constituting the etching mask film has better adhesion with the resist film than the conventional silicon compound, it is possible to suppress the collapse of the resist pattern.

In one embodiment of the present invention, the lower light shielding film is resistant to fluorine-based etching (F-based) and non-oxygen-containing chlorine-based etching (Cl-based), and can be etched by oxygen-based etching (O-based). Preferably there is. As a material having such characteristics, there is a ruthenium simple substance or a ruthenium compound.

In one embodiment of the present invention, films and substrates other than the etching mask film are resistant to oxygen-containing chlorine-based etching (Cl / O system) for removing the etching mask film. That is, the lower light shielding film is resistant to oxygen-containing chlorine-based etching (Cl / O-based). Further, the film and the substrate other than the upper light-shielding film are resistant to non-oxygen-containing chlorine-based etching (Cl-based) for removing the upper light-shielding film. Furthermore, films and substrates other than the lower light shielding film have resistance to oxygen-based etching (O-based) for removing the lower light shielding film. Therefore, it is possible to set conditions suitable for film removal without being limited to damage to other films and substrates, dimension control, depth control, etc. like the conventional phase shift mask with etching mask, The residue of the etching mask film, the upper light shielding film, and the lower light shielding film can be reduced. Further, when the etching mask film, the upper light shielding film, and the lower light shielding film are subjected to dry etching correction, the etching mask film residue is removed by oxygen-containing chlorine etching (Cl / O system), and the upper light shielding film residue is removed. If removed by non-oxygen-containing chlorine-based etching (Cl-based) and the residue of the lower light shielding film is removed by oxygen-based etching (O-based), only the residue is corrected without damaging the phase shift film and the substrate. can do.

According to the present invention, defects can be easily corrected, phase resolution mask pattern resolution improvement and dimension improvement can be achieved at the same time, etching mask film and light shielding film residue suppression, etching mask film and light shielding film It is possible to provide a phase shift mask blank, a phase shift mask, and a method for manufacturing the phase shift mask that enable dry etching correction of residues.

It is a section schematic diagram showing the phase shift mask blank concerning a 1st embodiment. It is the cross-sectional schematic which shows the phase shift mask blank which concerns on 2nd Embodiment. It is a section schematic diagram showing the phase shift mask blank concerning a 3rd embodiment. It is a section schematic diagram showing the phase shift mask blank concerning a 4th embodiment. It is a section schematic diagram showing the phase shift mask blank concerning a 5th embodiment. It is a section schematic diagram showing the phase shift mask blank concerning a 6th embodiment. It is the schematic diagram which expanded the effective area of the phase shift mask blank concerning the comparative example 1 which provided the etching stopper layer. It is the schematic diagram which expanded the effective area of the phase shift mask concerning the comparative example 2 which provided the etching stopper layer on both sides of the phase shift film. It is a figure similar to FIG. 8 concerning this Embodiment. It is the cross-sectional schematic diagram which shows in order the manufacturing method of the phase shift mask using the phase shift mask blank which concerns on 1st Embodiment. It is the cross-sectional schematic which shows the manufacturing method of the phase shift mask using the phase shift mask blank which concerns on 2nd Embodiment in order. It is the cross-sectional schematic which shows in order the manufacturing method of the phase shift mask using the phase shift mask blank which concerns on 3rd Embodiment. It is the cross-sectional schematic which shows the manufacturing method of the phase shift mask using the phase shift mask blank which concerns on 4th Embodiment in order. It is the cross-sectional schematic which shows in order the manufacturing method of the phase shift mask using the phase shift mask blank which concerns on 5th Embodiment. It is the cross-sectional schematic which shows the manufacturing method of the phase shift mask using the phase shift mask blank which concerns on 6th Embodiment in order. It is an expanded cross-sectional schematic diagram which shows the etching mask film | membrane of a phase shift mask using the phase shift mask blank which concerns on this embodiment, and the residue correction method of a light shielding film. It is an expanded cross-sectional schematic diagram which shows the etching mask film | membrane of a phase shift mask using the phase shift mask blank which concerns on this embodiment, and the residue correction method of a light shielding film.

Hereinafter, some embodiments for carrying out the present invention will be described with reference to the drawings. Note that the schematic cross-sectional view does not accurately reflect the actual dimensional ratio and the number of patterns, and the amount of digging of the substrate and the amount of damage to the film are omitted.

A phase shift mask blank according to an embodiment described below is a halftone phase shift mask blank used for producing a phase shift mask to which exposure light having a wavelength of 20 nm or more and a wavelength of 200 nm or less is applied, and at least exposure. Oxygen-containing chlorine-based etching (Cl / O-based), non-oxygen-containing chlorine-based etching (Cl-based), and oxygen-based etching (O-based) laminated on a transparent substrate with no other film interposed therebetween The phase shift film is resistant to fluorine and can be etched by fluorine-based etching (F-based), and is resistant to oxygen-containing chlorine-based etching (Cl / O-based) formed on the phase-shifted film. And an upper light-shielding film that can be etched by fluorine-based etching (F-based) and non-oxygen-containing chlorine-based etching (Cl-based), and formed above the upper light-shielding film. Resistant to fluorine-based etching (F-based), non-oxygen-containing chlorine-based etching (Cl-based) and oxygen-based etching (O-based), and etched with oxygen-containing chlorine-based etching (Cl / O-based) It has a possible etching mask film. However, an etching stopper layer is not provided between the phase shift film and the substrate.

Furthermore, the phase shift mask blank according to this embodiment is resistant to fluorine-based etching (F-based) and non-oxygen-containing chlorine-based etching (Cl-based), and can be etched by oxygen-based etching (O-based). A lower light-shielding film is provided between the phase shift film and the upper light-shielding film. This lower light-shielding film contains ruthenium and has a film thickness of 2 nm or more and 30 nm or less.

The lower layer light shielding film and the upper layer light shielding film exhibit a light shielding function. That is, by providing the lower light shielding film, the thickness of the upper light shielding film can be reduced accordingly. For example, when tantalum is contained in the upper light-shielding film, etching is generally difficult because etching becomes difficult due to oxidation. In this case, if the thickness of the upper light-shielding film can be reduced by the amount of the lower light-shielding film, the processing efficiency is improved and the residual probability is improved.

FIG. 1 is a schematic cross-sectional view showing a phase shift mask blank according to the first embodiment. A phase shift mask blank 10 in FIG. 1 includes a substrate 11 transparent to an exposure wavelength, a phase shift film 12 formed on the substrate 11, and a light shielding film (upper layer light shielding) formed on the phase shift film 12. And an etching mask film 14 formed on the light shielding film 13. There is no etching stopper layer between the substrate 11 and the phase shift film 12. In the phase shift mask using the phase shift mask blank 10, the etching mask film 14 is not partially removed but remains on the mask.

FIG. 2 is a schematic cross-sectional view showing a phase shift mask blank according to the second embodiment. The phase shift mask blank 10 of FIG. 2 includes a substrate 11 that is transparent to the exposure wavelength, a phase shift film 12 formed on the substrate 11, and a lower light shielding film 18 formed on the phase shift film 12. The upper light shielding film 13 is formed on the lower light shielding film 18 and the etching mask film 14 is formed on the upper light shielding film 13. There is no etching stopper layer between the substrate 11 and the phase shift film 12. In the phase shift mask using the phase shift mask blank 10, the etching mask film 14 is not partially removed but remains on the mask.

FIG. 3 is a schematic sectional view showing a phase shift mask blank according to the third embodiment. The phase shift mask blank 20 of FIG. 3 includes a substrate 21 transparent to the exposure wavelength, a phase shift film 22 formed on the substrate 21, and a light shielding film (upper layer light shielding) formed on the phase shift film 22. And an etching mask film 24 formed on the light shielding film 23. No etching stopper layer is provided between the substrate 21 and the phase shift film 22. In the phase shift mask using the phase shift mask blank 20, the etching mask film 24 is completely removed and does not remain on the mask.

FIG. 4 is a schematic sectional view showing a phase shift mask blank according to the fourth embodiment. The phase shift mask blank 20 of FIG. 4 includes a substrate 21 transparent to the exposure wavelength, a phase shift film 22 formed on the substrate 21, and a lower light shielding film 28 formed on the phase shift film 22. The upper light shielding film 23 is formed on the lower light shielding film 28 and the etching mask film 24 is formed on the upper light shielding film 23. No etching stopper layer is provided between the substrate 21 and the phase shift film 22. In the phase shift mask using the phase shift mask blank 20, the etching mask film 24 is completely removed and does not remain on the mask.

Here, there is no special limitation on the

substrates

11 and 21 that are transparent to the exposure wavelength, and quartz glass, CaF _2, aluminosilicate glass, or the like is generally used.

The

phase shift films

12 and 22 contain silicon and contain at least one selected from transition metals, nitrogen, oxygen, and carbon. Specifically, silicon oxide films, nitride films, and oxynitride films Or a single layer film of silicon and transition metal oxide film, nitride film, oxynitride film, or a multi-layer film or a gradient film thereof, and the transmittance and level with respect to the exposure wavelength by appropriately selecting the composition and film thickness. The phase difference is adjusted. As the transition metal, molybdenum, titanium, vanadium, cobalt, nickel, zirconium, niobium, hafnium, or the like can be used, but molybdenum is preferable.

The transmittance value is 3% or more and less than 100% with respect to the transmittance of the substrate when the final phase shift mask is completed, and it is possible to appropriately select the optimum transmittance according to the desired wafer pattern. However, the transmittance is generally 5% or more and 40% or less. The value of the phase difference is preferably 170 degrees or more and 190 degrees or less, particularly 175 degrees or more and 180 degrees or less when the final phase shift mask is completed. When etching the

phase shift films

12 and 22, it is common to dig a substrate of about 1 nm to 3 nm at the same time to prevent the phase shift film from coming off and to finely adjust the phase difference. Therefore, it is necessary to form the

phase shift films

12 and 22 with a phase difference shallower than a desired value when the mask is completed in consideration of the digging amount of the substrate.

The composition of the

phase shift films

12 and 22 varies depending on the desired combination of transmittance and phase difference. For example, in the case of a silicon and molybdenum oxynitride film having a transmittance of 6% and a phase difference of 177 degrees, oxygen-containing chlorine-based etching (Cl / O-based), non-oxygen-containing chlorine-based etching (Cl-based), and oxygen-based etching (O In order to realize resistance to (system), processability to fluorine-based etching (F system), and resistance to various chemical cleaning, silicon is 20 atom% or more and 60 atom% or less, particularly 30 atom% or more and 50 atom% or less. Molybdenum is 0 atomic% to 20 atomic%, particularly 0 atomic% to 10 atomic%, oxygen is 0 atomic% to 20 atomic%, particularly 0 atomic% to 10 atomic%, and nitrogen is 30 It is preferable that they are atom% or more and 80 atom% or less, especially 40 atom% or more and 70 atom% or less.

In addition, when the phase shift film is a multi-layer film or an inclined film, it contains a transition metal having a strong resistance to non-oxygen-containing chlorine-based etching (Cl-based) or oxygen-based etching (O-based) applied to the removal of the light shielding film. It is preferable to form a silicon compound film with a small amount or no content on the outermost surface. Specifically, it is preferable to form SiO ₂ or SiON on the outermost surface of the phase shift film. In particular, in the

phase shift films

12 and 22 having no etching stopper layer in the lower layer, even if strong etching conditions for strong cleaning or etching mask film removal are applied, the outermost SiO ₂ or SiON may be damaged. Since substrates having the same composition are also damaged at the same time, it is possible to suppress fluctuations in phase difference and transmittance with respect to the substrate.

Further, the upper

light shielding films

13 and 23 are made of a tantalum compound not containing silicon, and are a single layer film containing one or more selected from nitrogen, boron, oxygen and carbon, or a multilayer film or a gradient film thereof. Preferably, it is a film mainly composed of tantalum nitride. The reason why silicon is not contained is to prevent SiO ₂ and SiN that are difficult to process by non-oxygen-containing chlorine-based etching (Cl-based) from being mixed in the film.

The film thickness of the upper light shielding film 13 varies depending on the transmittance of the phase shift film, but the light shielding film (including the lower light shielding film, the same applies hereinafter), the phase shift film, and the etching mask film are combined. The OD value (optical density) with respect to the exposure wavelength is adjusted to 2.5 or more, more preferably 2.8 or more. For example, when the transmittance of the phase shift film is 6%, the film thickness of the upper light shielding film 13 (the sum of the lower light shielding film 18 and the same hereinafter) is 10 nm to 35 nm, particularly 15 nm to 30 nm. preferable.

On the other hand, the film thickness of the upper light-shielding film 23 (the sum of the lower light-shielding films 28, the same applies hereinafter) also varies depending on the transmittance of the phase shift film. Therefore, the OD value (optical density) with respect to the exposure wavelength is adjusted to be 2.5 or more, more preferably 2.8 or more for the light shielding film and the phase shift film. For example, when the transmittance of the phase shift film is 6%, the thickness of the light shielding film is preferably 15 nm to 50 nm, particularly preferably 20 nm to 45 nm.

Further, the upper light shielding film 23 may have a function as an antireflection layer. In this case, it is preferable to suppress the reflectance with respect to the exposure wavelength to, for example, 45% or less, particularly 30% or less in order to suppress multiple reflection between the phase shift mask and the projection exposure surface during exposure. Furthermore, it is preferable that the reflectance with respect to the wavelength (for example, 257 nm) used for the reflection inspection of the phase shift mask blank or the phase shift mask is, for example, 30% or less, in order to detect defects with high accuracy. In order to increase the effect as the antireflection layer, a method of increasing the gas content on the surface side of the light shielding film to obtain a higher refractive index and lower extinction coefficient is generally used.

The composition of the upper light shielding film 13 is such that tantalum is used to realize resistance to oxygen-containing chlorine-based etching (Cl / O system), processability to non-oxygen-containing chlorine-based etching (Cl system), and resistance to various chemical cleaning. 50 atom% or more, 100 atom% or less, particularly 60 atom% or more, 90 atom% or less, nitrogen is 0 atom% or more, 70 atom% or less, particularly 10 atom% or more, 60 atom% or less, oxygen is 0 atom% or more 10 atom% or less, particularly 0 atom% or more, 5 atom% or less, carbon 0 atom% or more, 20 atom% or less, especially 0 atom% or more, 10 atom% or less, boron 0 atom% or more, 20 atom% In the following, it is particularly preferably 0 atomic% or more and 10 atomic% or less. Further, the composition of the upper light shielding film 23 is resistant to oxygen-containing chlorine-based etching (Cl / O-based), processability to non-oxygen-containing chlorine-based etching (Cl-based), an effect as an antireflection layer, and various chemical solution cleaning In order to realize resistance, tantalum is 40 atomic% or more and 90 atomic% or less, particularly 50 atomic% or more and 80 atomic% or less, nitrogen is 10 atomic% or more and 70 atomic% or less, particularly 10 atomic% or more, 60 atoms or less. %, Oxygen is 0 atomic% or more, 20 atomic% or less, especially 0 atomic% or more, 10 atomic% or less, carbon is 0 atomic% or more, 20 atomic% or less, especially 0 atomic% or more, 10 atomic% or less, boron Is preferably 0 atom% or more and 20 atom% or less, particularly preferably 0 atom% or more and 10 atom% or less.

Alternatively, the upper light shielding film is preferably made of a tantalum compound or a silicon compound. The tantalum compound preferably contains tantalum and one or more selected from nitrogen, boron, silicon, oxygen and carbon. The silicon compound preferably contains silicon and contains at least one selected from molybdenum, titanium, vanadium, cobalt, nickel, zirconium, niobium, hafnium, nitrogen, oxygen, and carbon.

The lower light-shielding

films

18 and 28 are ruthenium alone or a ruthenium compound having a ruthenium content of 50 atomic% or more, specifically, one or more kinds selected from ruthenium alone or ruthenium and nitrogen, boron, carbon, and oxygen. It is preferable that it consists of a compound of either of these materials, one or more materials selected from niobium and zirconium, or both. The film thickness of the lower

light shielding films

18 and 28 is preferably 2 nm or more and 30 nm or less, particularly 5 nm or more and 20 nm or less in order to achieve both sufficient etching resistance and light shielding properties. Etching of the lower

light shielding films

18 and 28 can be performed by oxygen-based dry etching (O-based), and in addition to oxygen gas, an inert gas such as argon gas or helium gas may be mixed as necessary. . The lower

light shielding films

18 and 28 are resistant to fluorine-based etching (F-based) and non-oxygen-containing chlorine-based etching (Cl-based).

Further, the

etching mask films

14 and 24 are a single chromium film, a single-layer film containing chromium and one or more selected from nitrogen, oxygen, and carbon, or a multilayer film or a gradient film thereof. The film thickness of the etching mask film 14 is preferably 2 nm or more and 30 nm or less, particularly 20 nm or less in order to reduce resist damage during dry etching of the etching mask film and to realize thinning of the resist. The etching mask film 14 may have a function as an antireflection layer. In this case, it is preferable to suppress the reflectance with respect to the exposure wavelength to, for example, 45% or less, particularly 30% or less in order to suppress multiple reflection between the phase shift mask and the projection exposure surface during exposure. Furthermore, it is preferable that the reflectance with respect to the wavelength (for example, 257 nm) used for the reflection inspection of the phase shift mask blank or the phase shift mask is, for example, 30% or less, in order to detect defects with high accuracy. In order to obtain a sufficient antireflection effect, the thickness of the etching mask film 14 in the case of providing the function as the antireflection layer is preferably 5 nm or more. On the other hand, the film thickness of the etching mask film 24 is preferably 2 nm or more and 30 nm or less, particularly 15 nm or less in order to reduce resist damage during dry etching of the etching mask film and realize thinning of the resist. In order to prevent pinholes during film formation and film disappearance during etching or cleaning, the thickness is preferably 3 nm or more.

The composition of the etching mask film 14 is a resistance to fluorine-based etching (F-based), non-oxygen-containing chlorine-based etching (Cl-based) and oxygen-based etching (O-based), and processing for oxygen-containing chlorine-based etching (Cl / O-based). In order to realize properties, an effect as an antireflection layer, and resistance to various chemical cleaning, chromium is 30 atomic% or more and 100 atomic% or less, particularly 35 atomic% or more and 50 atomic% or less, and oxygen is 0 atomic% or more. 60 atom% or less, particularly 20 atom% or more, 60 atom% or less, nitrogen is 0 atom% or more, 50 atom% or less, particularly 0 atom% or more, 30 atom% or less, carbon is 0 atom% or more, 30 atom%. In the following, it is particularly preferably 0 atomic% or more and 20 atomic% or less.

The etching mask film 24 is composed of fluorine-based etching (F-based), non-oxygen-containing chlorine-based etching (Cl-based) and oxygen-based etching (O-based), oxygen-containing chlorine-based etching (Cl / O-based). In order to realize the workability of the resin and the resistance to various chemical cleaning, chromium is 30 atomic% or more and 100 atomic% or less, particularly 50 atomic% or more and 100 atomic% or less, and oxygen is 0 atomic% or more and 50 atomic% or less. In particular, 0 atom% or more and 40 atom% or less, nitrogen is 0 atom% or more and 50 atom% or less, particularly 0 atom% or more and 40 atom% or less, carbon is 0 atom% or more and 30 atom% or less, particularly 0 atom % Or more and 20 atomic% or less is preferable.

Subsequently, phase shift mask blanks according to the fifth and sixth embodiments will be described. In the phase shift mask blanks according to the fifth and sixth embodiments, an antireflection film layer is provided between the light shielding film and the etching mask film, so that the phase shift masks according to the first to fourth embodiments are provided. Different from mask blank.

FIG. 5 is a schematic sectional view showing a phase shift mask blank according to the fifth embodiment. The phase shift mask blank 10 ′ of FIG. 5 is formed on the substrate 11 ′ transparent to the exposure wavelength, the phase shift film 12 ′ formed on the substrate 11 ′, and the phase shift film 12 ′. A light shielding film (also referred to as an upper light shielding film) 13 ', an antireflection film 14' formed on the light shielding film 13 ', and an etching mask film 15' formed on the antireflection film 14 '. No etching stopper layer is provided between the substrate 11 'and the phase shift film 12'. In the phase shift mask using the phase shift mask blank 10 ', the etching mask film 15' is completely removed and does not remain on the mask.

FIG. 6 is a schematic sectional view showing a phase shift mask blank according to the sixth embodiment. The phase shift mask blank 10 ′ of FIG. 6 was formed on the substrate 11 ′ transparent to the exposure wavelength, the phase shift film 12 ′ formed on the substrate 11 ′, and the phase shift film 12 ′. On the lower light shielding film 18 ′, the upper light shielding film 13 ′ formed on the lower light shielding film 18 ′, the antireflection film 14 ′ formed on the upper light shielding film 13 ′, and the antireflection film 14 ′. The etching mask film 15 ′ is formed. No etching stopper layer is provided between the substrate 11 'and the phase shift film 12'. In the phase shift mask using the phase shift mask blank 10 ', the etching mask film 15' is completely removed and does not remain on the mask.

Here, there is no particular limitation on the substrate 11 ′ transparent to the exposure wavelength, and quartz glass, CaF _2, aluminosilicate glass, or the like is generally used.

The phase shift film 12 ′ contains silicon and contains at least one selected from transition metals, nitrogen, oxygen and carbon. Specifically, a silicon oxide film, a nitride film, an oxynitride film, Or a silicon and transition metal oxide film, nitride film, single layer film of oxynitride film, or a multilayer film or a gradient film thereof, and the transmittance and phase difference with respect to the exposure wavelength by appropriately selecting the composition and film thickness Is adjusted. As the transition metal, molybdenum, titanium, vanadium, cobalt, nickel, zirconium, niobium, hafnium, or the like can be used, but molybdenum is preferable.

The transmittance value is 3% or more and less than 100% with respect to the transmittance of the substrate when the final phase shift mask is completed, and it is possible to appropriately select the optimum transmittance according to the desired wafer pattern. However, the transmittance is generally 5% or more and 40% or less. The value of the phase difference is preferably 170 degrees or more and 190 degrees or less, particularly 175 degrees or more and 180 degrees or less when the final phase shift mask is completed. The substrate 11 ′ is finally dug by about 5 nm to 20 nm in the mask manufacturing process of patterning the phase shift film 12 ′ using fluorine-based etching (F system) and removing the antireflection film 14 ′. Therefore, the phase shift film 12 ′ needs to be formed with a phase difference shallower than a desired value when the mask is completed in consideration of the digging amount of the substrate. The film thickness of the phase shift film changes depending on the desired combination of transmittance and phase difference. For example, when a phase shift film having a transmittance of 6% and a phase difference of 177 degrees is formed, the film thickness should be 60 nm or more and 80 nm or less. preferable.

The composition of the phase shift film 12 ′ varies depending on a desired combination of transmittance and retardation. For example, when a silicon and molybdenum oxynitride film having a transmittance of 6% and a retardation of 177 degrees is formed, oxygen-containing chlorine is used. Resistant to chemical etching (Cl / O), non-oxygen-containing chlorine etching (Cl) and oxygen etching (O), processability to fluorine etching (F), and resistance to various chemical cleaning Therefore, silicon is 20 atom% or more and 60 atom% or less, particularly 30 atom% or more and 50 atom% or less, molybdenum is 0 atom% or more and 20 atom% or less, particularly 0 atom% or more and 10 atom% or less, oxygen Is 0 atom% or more and 20 atom% or less, particularly 0 atom% or more and 10 atom% or less, and nitrogen is 30 atom% or more and 80 atom% or less, particularly 40 atom% or more and 70 atom% or less. It is preferred.

In addition, when the phase shift film is a multi-layer film or an inclined film, a silicon compound with little or no transition metal content that has strong resistance to non-oxygen-containing chlorine-based etching (Cl-based) applied to the removal of the light-shielding film It is preferable to form a film on the outermost surface. Specifically, it is preferable to form SiO ₂ or SiON on the outermost surface of the phase shift film. In particular, in the phase shift film 12 ′ having no etching stopper layer in the lower layer, even if strong etching conditions such as strong cleaning or etching mask film removal are applied, even if the outermost SiO ₂ or SiON is damaged, Since substrates having the same composition are also damaged at the same time, it is possible to suppress fluctuations in phase difference and transmittance with respect to the substrate.

Further, the light shielding film 13 ′ is made of a tantalum compound not containing silicon, and is a single layer film containing one or more selected from nitrogen, boron, oxygen and carbon, or a multilayer film or a gradient film thereof. A film containing tantalum nitride as a main component is preferable. The reason why silicon is not contained is to prevent SiO ₂ and SiN that are difficult to process by non-oxygen-containing chlorine-based etching (Cl-based) from being mixed in the film. The film thickness of the light-shielding film 13 ′ (including the lower-layer light-shielding film 18 ′, including the same, hereinafter the same) varies depending on the transmittance of the phase shift film, but the antireflection film, the light shielding film, and the phase shift film are different. The OD value (optical density) for the combined exposure wavelength is adjusted to 2.5 or more, more preferably 2.8 or more. For example, when the transmittance of the phase shift film is 6%, the thickness of the light shielding film 13 ′ is preferably 10 nm to 35 nm, and particularly preferably 15 nm to 30 nm.

The composition of the light shielding film 13 ′ is such that tantalum is used to realize resistance to oxygen-containing chlorine-based etching (Cl / O system), processability to non-oxygen-containing chlorine-based etching (Cl system), and resistance to various chemical cleaning. 50 atom% or more, 100 atom% or less, particularly 60 atom% or more, 90 atom% or less, nitrogen is 0 atom% or more, 70 atom% or less, particularly 10 atom% or more, 60 atom% or less, oxygen is 0 atom% or more 10 atom% or less, particularly 0 atom% or more, 5 atom% or less, carbon 0 atom% or more, 20 atom% or less, especially 0 atom% or more, 10 atom% or less, boron 0 atom% or more, 20 atom% In the following, it is particularly preferably 0 atomic% or more and 10 atomic% or less.

The lower light-shielding film 18 ′ is ruthenium alone or a ruthenium compound having a ruthenium content of 50 atomic% or more. Specifically, the ruthenium alone or ruthenium and one or more kinds selected from nitrogen, boron, carbon, and oxygen. It is preferable that it consists of a compound with one or both of one or more materials selected from the materials, niobium and zirconium. The film thickness of the lower

light shielding films

18 and 28 is preferably 2 nm or more and 30 nm or less, and particularly preferably 5 nm or more and 20 nm or less in order to achieve both sufficient etching resistance and light shielding properties. The film formation is performed by sputtering using an ion sputtering apparatus with the ruthenium simple substance or ruthenium compound as a target. Etching of the lower light shielding film 18 ′ can be performed by oxygen-based dry etching (O-based), and an inert gas such as argon gas or helium gas may be mixed in addition to the oxygen gas as necessary. Further, the lower light shielding film 18 ′ is resistant to fluorine-based etching (F-based) and non-oxygen-containing chlorine-based etching (Cl-based).

The antireflection film 14 ′ is a single layer film made of a tantalum compound not containing silicon and containing one or more selected from nitrogen, boron, oxygen and carbon, or a multilayer film or a gradient film thereof. Preferably, it is a film mainly composed of tantalum oxide. Therefore, it is possible to continuously form films in the same film formation chamber without changing the sputtering film formation of the light shielding film and the target. As an antireflection function, the reflectance with respect to the exposure wavelength is suppressed to 45% or less, particularly 30% or less, in order to suppress multiple reflections between the phase shift mask and the projection exposure surface during exposure. preferable. Furthermore, it is preferable that the reflectance with respect to the wavelength (for example, 257 nm) used for the reflection inspection of the phase shift mask blank or the phase shift mask is, for example, 30% or less, in order to detect defects with high accuracy. The film thickness of the antireflection film 14 ′ is preferably 2 nm or more and 20 nm or less, and particularly 15 nm or less in order to obtain a sufficient antireflection effect. Furthermore, 3 nm or more is preferable in order to prevent pinholes during film formation and film disappearance during etching and cleaning.

The composition of the antireflection film 14 ′ is such that it has resistance to oxygen-containing chlorine-based etching (Cl / O system) and non-oxygen-containing chlorine-based etching (Cl system), processability to fluorine-based etching (F system), antireflection effect, And, in order to realize resistance to various chemical cleaning, tantalum is 10 atomic% or more and 70 atomic% or less, particularly 20 atomic% or more and 60 atomic% or less, nitrogen is 0 atomic% or more, 20 atomic% or less, especially 0 atom. % Or more, 10 atom% or less, oxygen 40 atom% or more, 90 atom% or less, especially 50 atom% or more, 80 atom% or less, carbon 0 atom% or more, 20 atom% or less, especially 0 atom% or more, 10 It is preferable that the atomic% or less and boron be 0 atomic% or more and 20 atomic% or less, particularly 0 atomic% or more and 10 atomic% or less.

Further, the etching mask film 15 'is a single layer film containing chromium alone, chromium and at least one selected from nitrogen, oxygen and carbon, or a multilayer film or a gradient film thereof. The film thickness of the etching mask film 15 ′ is preferably 2 nm or more and 30 nm or less, particularly 15 nm or less in order to reduce resist damage during dry etching of the etching mask film and to realize thinning of the resist. Furthermore, 3 nm or more is preferable in order to prevent pinholes during film formation and film disappearance during etching and cleaning.

The composition of the etching mask film 15 ′ is resistant to fluorine-based etching (F-based), non-oxygen-containing chlorine-based etching (Cl-based) and oxygen-based etching (O-based), and to oxygen-containing chlorine-based etching (Cl / O-based). In order to realize processability and resistance to chemical cleaning, chromium is 30 atomic% to 100 atomic%, particularly 50 atomic% to 100 atomic%, oxygen is 0 atomic% to 50 atomic%, In particular, 0 atom% or more and 40 atom% or less, nitrogen is 0 atom% or more and 50 atom% or less, especially 0 atom% or more and 40 atom% or less, carbon is 0 atom% or more and 30 atom% or less, especially 0 atom%. As mentioned above, it is preferable that it is 20 atomic% or less.

The phase shift film, the light shielding film, the antireflection film, and the etching mask film of the phase shift mask blank according to each embodiment described above can be formed by any known method. The most preferable method for obtaining a film having excellent homogeneity is a sputter film formation method, but it is not necessary to limit to the sputter film formation method.

The target and sputtering gas are selected according to the film composition. For example, as a method for forming a film containing chromium, a target containing chromium is used, and only an inert gas such as argon gas, only a reactive gas such as oxygen, or a mixture of an inert gas and a reactive gas is used. The method of performing reactive sputtering in gas can be mentioned. The flow rate of the sputtering gas may be adjusted according to the film characteristics, and may be constant during film formation. When the amount of oxygen or nitrogen is to be changed in the thickness direction of the film, it is changed according to the target composition. May be. Further, the power applied to the target, the distance between the target and the substrate, and the pressure in the deposition chamber may be adjusted. In addition, for example, in the formation of a film containing silicon and metal, a target in which the content ratio of silicon and metal is adjusted may be used alone, or a silicon target, a metal target, and silicon and metal A plurality of targets may be appropriately selected from the targets consisting of

The phase shift mask can be obtained by patterning or removing each film of the phase shift mask blank according to each embodiment described above into a desired pattern.

Here, the effect of not providing the etching stopper layer on the substrate will be described. FIG. 7 is an enlarged schematic view of the effective area of the phase shift mask blank according to Comparative Example 1 provided with the etching stopper layer. In FIG. 7, the etching stopper layer 2 is formed on the substrate 3, and the phase shift film 1 is formed on the etching stopper layer 2.

The etching stopper layer 2 can be formed of, for example, a mixed film containing silicon and aluminum, but there may be a defect C in the film as shown in FIG. In this case, if the defect C exists in the region through which the exposure light DUV passes, a part of the exposure light that passes through the etching stopper layer 2 is hindered, and there is a possibility that high-precision exposure cannot be performed.

Similarly, if a defect such as a defect A or a bulge B occurs on the surface of the substrate 3, there is a possibility that the passage of the exposure light DUV may be hindered. Such a problem can be corrected if the surface of the substrate 3 is exposed, such that the defect A is filled with a transparent material and the ridge B is deleted. However, when the etching stopper layer 2 is formed on the substrate 3, the above-described correction is impossible. Therefore, the phase shift mask blank in which such a defect has occurred must be discarded, and the yield deteriorates. To do. On the other hand, if the etching stopper layer is not provided as in this embodiment, the above-described problems do not occur.

Next, the effect of using ruthenium alone or a ruthenium compound as the lower light shielding film will be described. In the second, fourth, and sixth embodiments, a lower light shielding film is provided between the phase shift film and the upper light shielding film. For this reason, the thickness of the upper light shielding film can be reduced by the amount of the lower light shielding film. For example, when the upper light-shielding film is formed of a compound containing tantalum, the film becomes hard due to oxidation caused by cleaning, etching, natural oxidation, etc., and therefore it takes a relatively long time to remove. On the other hand, processing time can be shortened by using a ruthenium simple substance or a ruthenium compound. Since the unnecessary lower light shielding film is removed by etching together with the upper light shielding film, there is also an effect that the correction of the phase shift film with, for example, a fluorine-based gas is not hindered.

FIG. 8 is an enlarged schematic view of the effective area of the phase shift mask according to Comparative Example 2 in which the etching stopper layer is provided with the phase shift film interposed therebetween. In FIG. 8, the lower etching stopper layer 2 is formed on the substrate 3, the phase shift film 1 is formed on the lower etching stopper layer 2, and the upper etching stopper layer 2 is formed on the phase shift film 1. . Here, the two etching stopper layers 2 are made of, for example, an aluminum compound.

In FIG. 8, when the phase shift mask that has been processed is inspected, it is assumed that, for example, a defect D is generated at a position that should be removed due to the presence of fine foreign matters. In this case, it is required to delete the defect D by correction processing, and the correction is usually performed by irradiation of an electron beam with fluorine gas assist. However, in the configuration of FIG. 8, since the upper etching stopper layer 2 is formed at a position where the electron beam is irradiated, the phase shift film 1 below the upper etching stopper layer 2 cannot be deleted. Therefore, processing becomes difficult, leading to a deterioration in yield.

On the other hand, in the case of the phase shift mask of the present embodiment shown in FIG. 9, the lower light shielding film is finally removed and only the phase shift film 1 remains on the substrate 3. Since the irradiation is not hindered, the defect D can be easily removed.

In this embodiment, a ruthenium simple substance or a lower light shielding film using a ruthenium compound is used as the etching stopper layer of the upper light shielding film using a tantalum compound. Therefore, since the etching resistance is different, the lower light shielding film can be used as a stopper layer for correcting the upper light shielding film. Further, the light shielding effect can be exhibited by the lower light shielding film together with the upper light shielding film. That is, the lower light shielding film has both the light shielding function and the etching suppression function.

Subsequently, preferred embodiments of a phase shift mask manufactured from the phase shift mask blank according to the first to sixth embodiments described above and a method of manufacturing the phase shift mask will be described.

FIG. 10 is a schematic cross-sectional view sequentially illustrating a method of manufacturing the phase shift mask 100 using the phase shift mask blank 10 shown in FIG. The members indicated by the reference numerals already described are the same as those in FIG. FIG. 10A shows a process of forming a resist pattern 15 by applying a resist film on the etching mask film 14, performing drawing, and then performing development processing. FIG. 10B shows a process of patterning the etching mask film 14 along the resist pattern 15 by oxygen-containing chlorine-based dry etching (Cl / O system). FIG. 10C shows a process of cleaning after removing the remaining resist pattern 15. FIG. 10D shows a process of patterning the light shielding film 13 along the pattern of the etching mask film 14 by non-oxygen-containing chlorine-based dry etching (Cl-based) and / or fluorine-based etching (F-based). Indicates.

FIG. 10E shows a step of patterning the phase shift film 12 by fluorine-based dry etching (F system) along the pattern of the etching mask film 14 and the light shielding film 13. FIG. 10F shows a process of newly forming the second resist pattern 16. FIG. 10G shows a step of removing the etching mask film 14 in a region not covered with the second resist pattern 16 by oxygen-containing chlorine-based dry etching (Cl / O-based). FIG. 10H shows a non-oxygen-containing chlorine-based dry etching (Cl-based) or non-oxygen-containing chlorine-based dry etching (Cl-based) and fluorine-based film in a region not covered with the second resist pattern 16. The process of removing by both etching (F system) is shown. FIG. 10I shows a process of removing the remaining second resist pattern 16 after removing it. By executing the steps described above, the phase shift mask 100 is manufactured.

In this phase shift mask 100, the etching mask film 14 remains on the mask without being partially removed. Further, in FIG. 10I, an area denoted by reference numeral 101 represents an area where a circuit pattern formed on the phase shift mask 100 is arranged (hereinafter, this area is referred to as “effective area 101”). On the other hand, an area denoted by reference numeral 102 is an area where a pattern is arranged so as to surround an effective area 101 where a circuit pattern is arranged. Hereinafter, this area is referred to as an “outer peripheral portion 102”. The definition of the effective area and the outer peripheral portion is the same in the phase shift mask described with reference to FIGS. 11 to 15 below. In the example of the phase shift mask 100 described with reference to FIG. 10, the pattern formed in the effective area 101 includes only the substrate 11 and the phase shift film 12, and the light shielding film 13 and the etching mask film 14 are also laminated. The pattern exists only on the outer peripheral portion 102. However, as another embodiment, a pattern in which the substrate 11, the phase shift film 12, the light shielding film 13, and the etching mask film 14 are stacked may be formed in the effective area 101.

FIG. 11 is a schematic cross-sectional view sequentially illustrating a method of manufacturing the phase shift mask 100 using the phase shift mask blank 10 shown in FIG. The members indicated by the reference numerals already described are the same as those in FIG. FIG. 11A shows a process of forming a resist pattern 15 by applying a resist film on the etching mask film 14, performing drawing, and then performing development processing. FIG. 11B shows a process of patterning the etching mask film 14 along the resist pattern 15 by oxygen-containing chlorine-based dry etching (Cl / O system). FIG. 11C shows a process of removing the remaining resist pattern 15 after removing it. In FIG. 11D, the upper light shielding film 13 is patterned along the pattern of the etching mask film 14 by non-oxygen-containing chlorine-based dry etching (Cl-based) and / or fluorine-based etching (F-based). A process is shown. FIG. 11E shows a process of etching the lower light shielding film 18 by oxygen-based etching (O-based) along the pattern of the etching mask film 14 and the upper light shielding film 13.

FIG. 11F shows a process of patterning the phase shift film 12 by fluorine dry etching (F system). FIG. 11G shows a process of newly forming the second resist pattern 16. FIG. 11H shows a step of removing the etching mask film 14 in a region not covered with the second resist pattern 16 by oxygen-containing chlorine-based dry etching (Cl / O-based). FIG. 11I shows that the upper light shielding film 13 in a region not covered with the second resist pattern 16 is both non-oxygen-containing chlorine-based dry etching (Cl-based) and fluorine-based etching (F-based). The process of removing by one side is shown. FIG. 11J shows a step of removing the lower light shielding film 18 in a region not covered with the second resist pattern 16 by oxygen-based etching (O-based). FIG. 11K shows a process of removing the remaining second resist pattern 16 after removing it. By executing the steps described above, the phase shift mask 100 is manufactured.

In this phase shift mask 100, the etching mask film 14 remains on the mask without being partially removed. Further, in FIG. 11 (k), an area indicated by reference numeral 101 represents an effective area, and an area indicated by reference numeral 102 represents an outer peripheral portion. In the example of the phase shift mask 100 shown in FIG. 11 (k), the pattern formed in the effective area 101 is formed only of the substrate 11 and the phase shift film 12, and the upper light shielding film 13, the lower light shielding film 18, and The pattern in which the etching mask film 14 is laminated exists only in the outer peripheral portion 102. However, as another embodiment, a pattern in which the substrate 11, the phase shift film 12, the upper light shielding film 13, the lower light shielding film 18, and the etching mask film 14 are stacked may be formed in the effective area 101.

Next, FIG. 12 is a schematic cross-sectional view sequentially showing a method of manufacturing the phase shift mask 200 using the phase shift mask blank 20 shown in FIG. The members denoted by the reference numerals already described are the same as those in FIG. FIG. 12A shows a process of forming a resist pattern 25 by applying a resist film on the etching mask film 24, performing drawing, and then performing development processing. FIG. 12B shows a process of patterning the etching mask film 24 along the resist pattern 25 by oxygen-containing chlorine-based dry etching (Cl / O system). FIG. 12C shows a process of removing the remaining resist pattern 25 after removing it. 12D shows a step of patterning the light shielding film 23 along the pattern of the etching mask film 24 by non-oxygen-containing chlorine-based dry etching (Cl-based) and / or fluorine-based etching (F-based). Indicates.

FIG. 12E shows a process of patterning the phase shift film 22 by fluorine-based dry etching (F system) along the pattern of the etching mask film 24 and the light shielding film 23. FIG. 12F shows a process of removing the etching mask film 24 by oxygen-containing chlorine-based dry etching (Cl / O system). FIG. 12G shows a process of newly forming the second resist pattern 26. FIG. 12H shows a non-oxygen-containing chlorine-based dry etching (Cl-based) or non-oxygen-containing chlorine-based dry etching (Cl-based) and fluorine-based film in a region not covered with the second resist pattern 26. The process of removing by both etching (F system) is shown. FIG. 12I shows a process of removing the remaining second resist pattern 26 and then cleaning it. By executing the steps described above, the phase shift mask 200 is manufactured.

In this phase shift mask 200, the etching mask film 24 is completely removed and does not remain on the mask. In FIG. 12 (i), an area indicated by reference numeral 201 represents an effective area, and an area indicated by reference numeral 202 represents an outer peripheral portion. In the example of the phase shift mask 200 shown in FIG. 12I, the pattern formed in the effective area 201 is formed only from the substrate 21 and the phase shift film 22, and the pattern in which the light shielding film 23 is also laminated is It exists only in the outer periphery 202. However, as another embodiment, a pattern in which the substrate 21, the phase shift film 22, and the light shielding film 23 are stacked may be formed in the effective area 201.

Next, FIG. 13 is a schematic cross-sectional view sequentially illustrating a method of manufacturing the phase shift mask 200 using the phase shift mask blank 20 shown in FIG. The members indicated by the reference numerals already described are the same as those in FIG. FIG. 13A shows a process of forming a resist pattern 25 by applying a resist film on the etching mask film 24, performing drawing, and then performing development processing. FIG. 13B shows a process of patterning the etching mask film 24 along the resist pattern 25 by oxygen-containing chlorine-based dry etching (Cl / O system). FIG. 13C shows a process of removing the remaining resist pattern 25 after removing it. In FIG. 13D, the upper light shielding film 23 is patterned along the pattern of the etching mask film 24 by non-oxygen-containing chlorine-based dry etching (Cl-based) and / or fluorine-based etching (F-based). A process is shown. FIG. 13E shows a process of etching the lower light-shielding film 28 by oxygen-based etching (O-based) along the pattern of the etching mask film 24 and the upper light-shielding film 23.

FIG. 13F shows a step of patterning the phase shift film 22 by fluorine-based dry etching (F system) along the pattern of the etching mask film 24 and the light shielding film 23 and the lower light shielding film 28. FIG. 13G shows a process of removing the etching mask film 24 by oxygen-containing chlorine-based dry etching (Cl / O system). FIG. 13H shows a process of newly forming the second resist pattern 26. FIG. 13I shows that the light shielding film 23 in a region not covered with the second resist pattern 26 is both non-oxygen-containing chlorine-based dry etching (Cl-based) and fluorine-based etching (F-based), or one of them. The process of removing is shown. FIG. 13J shows a step of removing the lower light shielding film 28 in a region not covered with the second resist pattern 26 by oxygen-based etching (O-based). FIG. 13K shows a process of removing the remaining second resist pattern 26 and then cleaning it. By executing the steps described above, the phase shift mask 200 is manufactured.

In this phase shift mask 200, the etching mask film 24 is completely removed and does not remain on the mask. In FIG. 13 (k), an area indicated by reference numeral 201 represents an effective area, and an area indicated by reference numeral 202 represents an outer peripheral portion. In the example of the phase shift mask 200 shown in FIG. 13K, the pattern formed in the effective area 201 is formed only from the substrate 21 and the phase shift film 22, and the upper light shielding film 23 and the lower light shielding film 28 are also formed. The stacked pattern exists only in the outer peripheral portion 202. However, as another embodiment, a pattern in which the substrate 21, the phase shift film 22, the upper light shielding film 23, and the lower light shielding film 28 are stacked may be formed in the effective area 201.

In the steps of FIGS. 10A, 11A, 12A, and 13A, either a positive resist or a negative resist may be used as the resist film material. However, it is preferable to use a chemically amplified resist for electron beam drawing that enables formation of a high-precision pattern. The thickness of the resist film is, for example, in the range of not less than 50 nm and not more than 200 nm. In particular, when producing a phase shift mask that requires fine pattern formation, it is necessary to reduce the resist film thickness so that the aspect ratio of the resist pattern does not increase in order to prevent pattern collapse. Film thickness is preferred. On the other hand, the lower limit of the thickness of the resist film is determined by comprehensively considering conditions such as etching resistance of the resist material to be used, and is preferably 60 nm or more. When a chemically amplified resist film for electron beam writing is used as the resist film, the energy density of the electron beam at the time of writing is in the range of 10 to 100 μC / cm ^2. After this drawing, heat treatment and development processing are performed. To obtain a resist pattern.

In addition, in the steps of FIGS. 10B, 11B, 12B, and 13B, conditions for oxygen-containing chlorine-based dry etching (Cl / O-based) for patterning the etching mask film are performed. May be a known one that has been conventionally used for dry etching of chromium compound films, and in addition to chlorine gas and oxygen gas, an inert gas such as nitrogen gas or helium gas may be mixed as necessary. Good. Since the lower light-shielding film has resistance to oxygen-containing chlorine-based dry etching (Cl / O-based), it remains without being removed or patterned in this step.

Further, in the steps of FIG. 10C, FIG. 11C, FIG. 12C, and FIG. 13C, the resist pattern can be removed by dry etching. To wet peel.

Also, in the steps of FIGS. 10D, 11D, 12D, and 13D, the conditions for non-oxygen-containing chlorine-based dry etching (Cl-based) for patterning the upper light-shielding film are as follows. In addition to chlorine gas, an inert gas such as nitrogen gas or helium gas may be mixed as necessary. Since the upper etching mask film and the lower light shielding film have resistance to non-oxygen-containing chlorine-based dry etching (Cl-based), they remain without being removed or patterned in this step. In addition, when the outermost surface composition of the upper light-shielding film changes due to etching or cleaning, and the etching rate in the non-oxygen-containing chlorine-based etching (Cl-based) is lowered, for the purpose of more efficiently removing the light-shielding film outermost surface, Fluorine-based etching (F system) can be added before non-oxygen-containing chlorine-based dry etching (Cl system).

In addition, in the steps of FIGS. 11E and 13E, the oxygen-based dry etching (O) system for patterning the lower light-shielding film uses an argon gas, a helium gas, or the like as necessary in addition to the oxygen gas. An inert gas may be mixed. Since the etching mask film, the upper light shielding film, and the phase shift film have resistance to oxygen-based dry etching (O-based), they remain without being removed or patterned in this step.

Further, in the steps of FIGS. 10E, 11F, 12E, and 13F, the fluorine-based dry etching (F-based) conditions for patterning the phase shift film have been conventionally performed. It may be a known one that has been used for dry etching of a silicon-based compound film, and the fluorine-based gas is generally CF ₄ , C ₂ F _6, or SF ₆ , and if necessary, nitrogen gas or helium An inert gas such as a gas may be mixed.

The uppermost etching mask film is resistant to fluorine-based dry etching (F system), and therefore remains in the process without being removed or patterned together with the light shielding film. 10 (e), 11 (f), 12 (e), and 13 (f), the substrate is simultaneously dug by about 1 nm to 3 nm to prevent the phase shift film from coming off and the phase difference of It is common to make fine adjustments.

Further, in the steps of FIG. 10 (f), FIG. 11 (g), FIG. 12 (g), and FIG. 13 (h), the drawing method may use laser drawing whose accuracy is lower than that of electron beam drawing. A resist film is applied, electron beam drawing or laser drawing is performed, and then a development process is performed to obtain a second resist pattern.

In the steps of FIGS. 12F and 13G, the oxygen-containing chlorine-based dry etching (Cl / O-based) conditions for removing the etching mask film are conventionally used for removing the chromium compound film. In addition to chlorine gas and oxygen gas, an inert gas such as nitrogen gas or helium gas may be mixed as necessary. Since the underlying light shielding film, phase shift film, and substrate are all resistant to oxygen-containing chlorine-based dry etching (Cl / O system), they remain without being removed or patterned in this step. Accordingly, it is possible to select an etching condition that facilitates lateral etching that can suppress residues (removal residue) of the etching mask film. As the etching conditions that facilitate the lateral etching, a higher pressure (low vacuum) and a larger over-etching amount are preferable than the etching conditions used in the steps of FIGS. 12B and 13B. The over-etching amount here is the ratio of the etching time that is extended after that to the etching time for completely removing the film.

In addition, in the steps of FIG. 10H, FIG. 11I, FIG. 12H, and FIG. 13I, the non-oxygen-containing chlorine-based dry etching (Cl-based) conditions for removing the upper light shielding film are as follows: In addition to chlorine gas, an inert gas such as nitrogen gas or helium gas may be mixed as necessary. Since the lower light shielding film, the phase shift film, and the substrate, which are lower layers, are all resistant to non-oxygen-containing chlorine-based dry etching (Cl-based), they remain without being removed or patterned in this step.

In the steps of FIGS. 11 (j) and 13 (j), oxygen-based dry etching (O-based) conditions for removing the lower light-shielding film are argon gas or helium gas as required in addition to oxygen gas. An inert gas such as may be mixed. Since the underlying phase shift film and the substrate are both resistant to oxygen-based dry etching (O-based), they remain without being removed or patterned in this step.

Therefore, it is possible to select an etching condition that facilitates lateral etching that can suppress residues (remaining removal) of the light shielding film. Etching conditions that facilitate the etching in the horizontal direction are based on the etching conditions used in the steps of FIGS. 10D, 11D, 11E, 12D, 13D, and 13E. However, a high pressure (low vacuum) and a large over-etching amount are preferable. The over-etching amount here is the ratio of the etching time that is extended after that to the etching time for completely removing the film.

Further, in the steps of FIGS. 10 (i), 11 (k), 12 (i), and 13 (k), the resist pattern can be removed by dry etching. To wet peel.

Subsequently, a phase shift mask and a method for manufacturing the phase shift mask manufactured from the phase shift mask blank according to the fifth and sixth embodiments will be described. FIG. 14 is a diagram for explaining a method of manufacturing the phase shift mask 100 ′ using the phase shift mask blank 10 ′ shown in FIG. 5. The members indicated by the reference numerals already described are the same as those in FIG. FIG. 14A shows a step of forming a resist pattern 16 ′ by applying a resist film on the etching mask film 15 ′, performing drawing, and then performing development processing. FIG. 14B shows a process of patterning the etching mask film 15 ′ by oxygen-containing chlorine-based dry etching (Cl / O system) along the resist pattern 16 ′. FIG. 14C shows a process of removing the remaining resist pattern 16 'after removing it. FIG. 14D shows a process of patterning the antireflection film 14 ′ by fluorine dry etching (F system) along the pattern of the etching mask film 15 ′. FIG. 14 (e) shows a case where non-oxygen-containing chlorine-based dry etching (Cl-based) and / or fluorine-based etching (F-based) is performed along the pattern of the etching mask film 15 ′ and the antireflection film 14 ′. A process of patterning the light shielding film 13 ′ will be described.

FIG. 14F shows a step of patterning the phase shift film 12 ′ by fluorine-based dry etching (F system) along the pattern of the etching mask film 15 ′, the antireflection film 14 ′, and the light shielding film 13 ′. FIG. 14G shows a process of removing the etching mask film 15 ′ by oxygen-containing chlorine-based dry etching (Cl / O system). FIG. 14H shows a process of newly forming the second resist pattern 17 '. FIG. 14I shows a process of removing the antireflection film 14 ′ in the region not covered with the second resist pattern 17 ′ by fluorine-based dry etching (F-based). FIG. 14J shows that the light shielding film 13 ′ in the region not covered with the second resist pattern 17 ′ is non-oxygen-containing chlorine-based dry etching (Cl-based) or non-oxygen-containing chlorine-based dry etching (Cl-based). The process of removing by both fluorine etching (F system) is shown. FIG. 14K shows a process of removing the remaining second resist pattern 17 'after removing it. By performing the above-described steps, the phase shift mask 100 ′ is manufactured.

In this phase shift mask 100 ', the etching mask film 15' is completely removed and does not remain on the mask. In FIG. 14 (k), an area indicated by reference numeral 101 'represents an effective area, and an area indicated by reference numeral 102' represents an outer peripheral portion. In the example of the phase shift mask 100 ′ of FIG. 14 (k), the pattern formed in the effective area 101 ′ is composed only of the substrate 11 ′ and the phase shift film 12 ′, and the light shielding film 13 ′ and the antireflection film 14 ′. Also, the laminated pattern exists only in the outer peripheral portion 102 '. However, as another embodiment, a pattern in which the substrate 11 ′, the phase shift film 12 ′, the light shielding film 13 ′, and the antireflection film 14 ′ are stacked may be formed in the effective area 101 ′.

FIG. 15 is a diagram for explaining a method of manufacturing the phase shift mask 100 ′ using the phase shift mask blank 10 ′ shown in FIG. 6. The members indicated by the reference numerals already described are the same as those in FIG. FIG. 15A shows a process of forming a resist pattern 16 ′ by applying a resist film on the etching mask film 15 ′, performing drawing, and then performing a development process. FIG. 15B shows a process of patterning the etching mask film 15 ′ by oxygen-containing chlorine-based dry etching (Cl / O system) along the resist pattern 16 ′. FIG. 15C shows a process of removing the remaining resist pattern 16 'after removing it. FIG. 15D shows a process of patterning the antireflection film 14 ′ by fluorine dry etching (F system) along the pattern of the etching mask film 15 ′. FIG. 15 (e) shows a case where non-oxygen-containing chlorine-based dry etching (Cl-based) and / or fluorine-based etching (F-based) is performed along the pattern of the etching mask film 15 ′ and the antireflection film 14 ′. A process of patterning the upper light shielding film 13 ′ is shown. FIG. 15F shows a step of patterning the lower light-shielding film 18 ′ by oxygen-based dry etching (O-based) along the pattern of the etching mask film 15 ′, the antireflection film 14 ′, and the upper light-shielding film 13 ′.

FIG. 15G shows the phase shift film 12 ′ by fluorine-based dry etching (F system) along the pattern of the etching mask film 15 ′, the antireflection film 14 ′, the upper light shielding film 13 ′, and the lower light shielding film 18 ′. The process of patterning is shown. FIG. 15H shows a process of removing the etching mask film 15 ′ by oxygen-containing chlorine-based dry etching (Cl / O system). FIG. 15I shows a process of newly forming the second resist pattern 17 '. FIG. 15J shows a step of removing the antireflection film 14 ′ in the region not covered with the second resist pattern 17 ′ by fluorine-based dry etching (F-based). FIG. 15 (k) shows that the upper light shielding film 13 ′ in the region not covered with the second resist pattern 17 ′ is subjected to both non-oxygen-containing chlorine-based dry etching (Cl-based) and fluorine-based etching (F-based), or The process of removing by either one is shown. FIG. 15L shows a step of removing the lower light shielding film 18 'in the region not covered with the second resist pattern 17' by oxygen-based dry etching (O-based). FIG. 15 (m) shows a process of removing the remaining second resist pattern 17 'after removing it. By performing the above-described steps, the phase shift mask 100 ′ is manufactured.

In this phase shift mask 100 ', the etching mask film 15' is completely removed and does not remain on the mask. In FIG. 15 (m), an area indicated by reference numeral 101 'represents an effective area, and an area indicated by reference numeral 102' represents an outer peripheral portion. In the example of the phase shift mask 100 ′ of FIG. 15 (m), the pattern formed in the effective area 101 ′ is composed only of the substrate 11 ′ and the phase shift film 12 ′, and the upper light shielding film 13 ′ and the lower light shielding film 18 are formed. The pattern in which 'and the antireflection film 14' are also laminated exists only in the outer peripheral portion 102 '. However, as another embodiment, a pattern in which the substrate 11 ′, the phase shift film 12 ′, the upper light shielding film 13 ′, the lower light shielding film 18 ′, and the antireflection film 14 ′ are stacked is formed in the effective area 101 ′. Also good.

In the processes of FIGS. 14A and 15A, the resist film material can be either a positive resist or a negative resist, but it can be used for electron beam lithography that enables the formation of a high-precision pattern. It is preferable to use a chemically amplified resist. The film thickness of the resist film is, for example, in the range of not less than 50 nm and not more than 200 nm. In particular, when producing a phase shift mask that requires fine pattern formation, it is necessary to reduce the resist film thickness so that the aspect ratio of the resist pattern does not increase in order to prevent pattern collapse. Film thickness is preferred. On the other hand, the lower limit of the thickness of the resist film is determined by comprehensively considering conditions such as etching resistance of the resist material to be used, and is preferably 60 nm or more. When a chemically amplified resist film for electron beam writing is used as the resist film, the energy density of the electron beam at the time of writing is in the range of 10 to 100 μC / cm ^2. After this drawing, heat treatment and development processing are performed. To obtain a resist pattern.

In the steps of FIGS. 14B and 15B, the oxygen-containing chlorine-based dry etching (Cl / O-based) conditions for patterning the etching mask film are the same as those in the conventional dry etching of a chromium compound film. It may be a known one that has been used, and in addition to chlorine gas and oxygen gas, an inert gas such as nitrogen gas or helium gas may be mixed as necessary. Since the lower antireflection film has resistance to oxygen-containing chlorine-based dry etching (Cl / O-based), it remains without being removed or patterned in this step.

In the steps of FIGS. 14C and 15C, the resist pattern can be removed by dry etching, but in general, the resist pattern is wet-exfoliated with a removing solution.

14D and 15D, the fluorine-based dry etching (F-based) conditions for patterning the antireflection film are CF ₄ , C ₂ F ₆ and SF ₆ as the fluorine-based gas. It is common and you may mix inert gas, such as nitrogen gas and helium gas, as needed. Since the upper etching mask film is resistant to fluorine-based dry etching (F-based), it remains without being removed or patterned in this step. Further, since the lower light-shielding film can be processed by fluorine-based dry etching (F-based), the light-shielding film may be patterned to such an extent that the entire film is not removed in this step.

14E and 15E, the non-oxygen-containing chlorine-based dry etching (Cl-based) conditions for patterning the upper light-shielding film include nitrogen gas and nitrogen gas as necessary in addition to chlorine gas. An inert gas such as helium gas may be mixed. Since the uppermost etching mask film and the lower phase shift film are resistant to non-oxygen-containing chlorine-based dry etching (Cl-based), they remain without being removed or patterned in this step.

In the step of FIG. 15F, the oxygen-based dry etching (O-based) conditions for patterning the lower light-shielding film are mixed with an inert gas such as argon gas or helium gas in addition to oxygen gas as necessary. May be. Since the upper light shielding film and the lower phase shift film have resistance to oxygen-based dry etching (O-based), they remain without being removed or patterned in this step.

14F and 15G, the fluorine-based dry etching (F-based) conditions for patterning the phase shift film have been conventionally used when dry-etching a silicon-based compound film. As the fluorine-based gas, CF ₄ , C ₂ F _6, and SF ₆ are generally used, and an inert gas such as nitrogen gas or helium gas may be mixed as necessary. Since the uppermost etching mask film is resistant to fluorine-based dry etching (F system), it remains without being removed or patterned in this step together with the antireflection film and the light shielding film. In FIGS. 14 (f) and 15 (g), it is common to simultaneously dig out the substrate by about 1 nm to 3 nm to prevent the phase shift film from coming off and to finely adjust the phase difference.

14G and 15H, the oxygen-containing chlorine-based dry etching (Cl / O-based) conditions for removing the etching mask film have been conventionally used for removing the chromium compound film. In addition to chlorine gas and oxygen gas, an inert gas such as nitrogen gas or helium gas may be mixed as necessary. The lower antireflection film, light shielding film, phase shift film, and substrate are all resistant to oxygen-containing chlorine-based dry etching (Cl / O-based), so they are not removed or patterned in this step. Remains. Accordingly, it is possible to select an etching condition that facilitates lateral etching that can suppress residues (removal residue) of the etching mask film. As the etching conditions that facilitate the lateral etching, a higher pressure (low vacuum) and a larger over-etching amount are preferable than the etching conditions used in the steps of FIGS. 14B and 15B. The over-etching amount here is the ratio of the etching time that is extended after that to the etching time for completely removing the film.

14 (h) and FIG. 15 (i), the drawing method may be laser drawing, which is less accurate than electron beam drawing. A resist film is applied, and electron beam drawing or laser drawing is performed. And a development process is performed thereafter to obtain a second resist pattern.

Further, in the step of FIG. 14 (i) and FIG. 15 (j), the conditions of fluorine dry etching for removing the antireflection film (F system), CF ₄ and _C 2 _{F 6} and SF ₆ as a fluorine-based gas It is common and you may mix inert gas, such as nitrogen gas and helium gas, as needed. Since the lower light-shielding film can also be removed by fluorine-based dry etching (F-based), part or all of the film may be removed in this step. 14 (i) and 15 (j), the substrate is also dug simultaneously. Therefore, in order to completely remove the antireflection film and realize a desired phase difference, the final digging amount of the substrate combined with the digging amounts in FIGS. 14 (g) and 15 (h). Is preferably adjusted from 5 nm to 20 nm.

14 (j) and 15 (k), the non-oxygen-containing chlorine-based dry etching (Cl-based) condition for removing the upper light-shielding film is not limited to chlorine gas, but may be nitrogen gas or An inert gas such as helium gas may be mixed. Since the lower light shielding film, the phase shift film, and the substrate, which are lower layers, are all resistant to non-oxygen-containing chlorine-based dry etching (Cl-based), they remain without being removed or patterned in this step.

In the process of FIG. 15 (l), the oxygen-based dry etching (O-based) conditions for removing the lower light-shielding film are mixed with an inert gas such as argon gas or helium gas in addition to oxygen gas as necessary. May be. Since the underlying phase shift film and the substrate are both resistant to oxygen-based dry etching (O-based), they remain without being removed or patterned in this step.

Therefore, it is possible to select an etching condition that facilitates lateral etching that can suppress residues (remaining removal) of the light shielding film. As the etching conditions that facilitate the lateral etching, a higher pressure (low vacuum) and a larger overetching amount are preferable than the etching conditions used in the steps of FIGS. 14 (e), 15 (e), and (f). The over-etching amount here is the ratio of the etching time that is extended after that to the etching time for completely removing the film.

In the steps of FIGS. 14 (k) and 15 (m), the resist pattern can be removed by dry etching, but in general, the resist pattern is wet-exfoliated with a remover.

As mentioned above, although the example of the method of producing a phase shift mask using the phase shift mask blank concerning each embodiment was explained, when a defect was detected by mask inspection, this defect was in the middle of the method explained above. A process to correct may be added. There are various defect correction methods depending on the type and size of the defect, but in the case of a black defect in which a part of the phase shift film is larger than the desired size, the defective portion is supplied while supplying a fluorine-based gas. A correction method (electron beam correction) in which only a defective portion is accurately removed by etching by irradiating an electron beam on the surface is generally used. In the present embodiment, the lower light shielding film using ruthenium alone or a ruthenium compound is finally removed, so that electron beam correction is not hindered.

Next, a preferred embodiment of the residue correction method in the case where residues of the etching mask film and the upper light shielding film (and the lower light shielding film) are generated in the phase shift mask manufactured in the process described above will be described.

FIG. 16 is an enlarged schematic cross-sectional view showing a method of correcting a residue of an etching mask film and a light shielding film of the phase shift mask 100 using the phase shift mask blank 10 shown in FIG. FIG. 16A shows a state of a part of the mask in which the etching mask film residue 14 a and the light shielding film residue 13 a exist on the phase shift film 12.

Next, FIG. 16B shows a process of newly forming a resist pattern 17 for residue correction so as not to cover the region where the

residues

13a and 14a are generated. In this step, a resist pattern 17 is obtained by forming a resist film, performing electron beam drawing or laser drawing, and developing the resist film. Alternatively, the resist pattern 17 may be obtained by performing spot exposure on the areas where the

residues

13a and 14a are generated and then developing the areas.

Next, FIG. 16C shows a step of removing the etching mask film residue 14a in a region not covered with the resist pattern 17 by oxygen-containing chlorine-based dry etching (Cl / O-based). Since the light shielding film residue 13a, the phase shift film 12 and the substrate 11 are resistant to oxygen-containing chlorine-based dry etching (Cl / O system), they remain without being removed or patterned in this step. The etching conditions are preferably selected so that the etching in the lateral direction is easy to proceed in order to remove the residue 14a of the etching mask film. Etching conditions that facilitate etching in the horizontal direction are the same as those used in the step of FIG.

Next, FIG. 16D shows a step of removing the light shielding film residue 13a in a region not covered with the resist pattern 17 by non-oxygen-containing chlorine-based dry etching (Cl-based). Since the phase shift film 12 and the substrate 11 are resistant to non-oxygen-containing chlorine-based dry etching (Cl-based), they remain without being removed or patterned in this step. As the etching conditions, it is desirable to select conditions that facilitate the lateral etching in order to remove the light shielding film residue 13a. Etching conditions that facilitate lateral etching are the same as those used in the process of FIG.

Next, FIG. 16E shows a process of removing the remaining resist pattern 17 and then cleaning it. Peeling and removal can be performed by dry etching, but in general, wet peeling is performed with a stripping solution. By this step, the residue correction of the etching mask film and the light shielding film of the phase shift mask 100 is completed.

FIG. 17 is an enlarged schematic cross-sectional view showing a method for correcting a residue of an etching mask film and a light shielding film of the phase shift mask 100 using the phase shift mask blank 10 shown in FIG. FIG. 17A shows a state of a part of the mask in which the residue 14a of the etching mask film, the residue 13a of the upper light shielding film, and the residue 18a of the lower light shielding film exist on the phase shift film 12.

Next, FIG. 17B shows a process of newly forming a resist pattern 17 for residue correction so as not to cover the regions where the

residues

13a, 14a and 18a are generated. In this step, a resist pattern 17 is obtained by forming a resist film, performing electron beam drawing or laser drawing, and developing the resist film. Alternatively, the resist pattern 17 may be obtained by performing spot exposure on the regions where the

residues

13a, 14a, and 18a are generated and then developing the regions.

Next, FIG. 17C shows a step of removing the etching mask film residue 14a in a region not covered with the resist pattern 17 by oxygen-containing chlorine-based dry etching (Cl / O-based). Since the upper light shielding film residue 13a, the lower light shielding film residue 18a, the phase shift film 12 and the substrate 11 are resistant to oxygen-containing chlorine-based dry etching (Cl / O-based), they are removed or patterned in this step. Remains. The etching conditions are preferably selected so that the etching in the lateral direction is easy to proceed in order to remove the residue 14a of the etching mask film. Etching conditions that facilitate lateral etching are the same as those used in the step of FIG.

Next, FIG. 17D shows a step of removing the residue 13a of the upper light shielding film in the region not covered with the resist pattern 17 by non-oxygen-containing chlorine-based dry etching (Cl-based). Since the lower layer light shielding film residue 18a, the phase shift film 12 and the substrate 11 are resistant to non-oxygen-containing chlorine-based dry etching (Cl-based), they remain without being removed or patterned in this step. As the etching conditions, it is desirable to select conditions that facilitate the lateral etching in order to remove the residue 13a of the upper light-shielding film. Etching conditions that facilitate the lateral etching are the same as those used in the step of FIG.

Next, FIG. 17E shows a process of removing the lower light shielding film residue 18a in the region not covered with the resist pattern 17 by oxygen-based dry etching (O-based). Since the phase shift film 12 and the substrate 11 have resistance to oxygen-based dry etching (O-based), they remain without being removed or patterned in this step. As the etching conditions, it is desirable to select a condition that facilitates the etching in the lateral direction in order to remove the residue 18a of the lower light shielding film. Etching conditions that facilitate lateral etching are the same as those used in the step of FIG.

Next, FIG. 17 (f) shows a process of removing the remaining resist pattern 17 and then cleaning it. Peeling and removal can be performed by dry etching, but in general, wet peeling is performed with a stripping solution. By this step, the residue correction of the etching mask film and the light shielding film of the phase shift mask 100 is completed.

Next, a preferred embodiment of a residue correction method in the case where an etching mask film residue is generated during the manufacture of the phase shift mask manufactured in the steps shown in FIGS.

The etching mask film is removed in the steps shown in FIGS. 14 (g) and 15 (h). If a part of the etching mask film cannot be completely removed and remains as a residue on the antireflection film, FIG. This residue can be detected by performing a reflective mask inspection after the steps shown in FIG. 14 (g) and FIG. 15 (h).

Next, the detected residue of the etching mask film is removed by oxygen-containing chlorine-based dry etching (Cl / O system). Here, since the antireflection film, the upper light shielding film, the lower light shielding film, the phase shift film, and the substrate are all resistant to oxygen-containing chlorine-based dry etching (Cl / O-based), they are removed or patterned in this step. It remains without being. The etching conditions are preferably selected so that the etching in the lateral direction is easy to proceed in order to remove the residue of the etching mask film. Etching conditions that facilitate lateral etching are the same as those used in the steps of FIGS. 14 (g) and 15 (h).

Next, it is confirmed that the residue of the etching mask film detected by the reflection mask inspection or SEM observation is completely removed. By this step, the residue correction of the etching mask film of the phase shift mask is completed. Thereafter, the steps shown in FIG. 14 (h) and FIG. 15 (i) and thereafter are preferably performed to continue manufacturing the phase shift mask.

Hereinafter, the embodiments of the present invention will be described more specifically by way of examples. However, the present invention is not limited to the following examples.

Example 1
A phase shift film made of silicon, molybdenum, oxygen and nitrogen was formed to a thickness of 66 nm on a quartz substrate using a DC sputtering apparatus using two targets. The target was molybdenum and silicon, and the sputtering gas was argon, oxygen, and nitrogen. When the composition of this phase shift film was analyzed by ESCA, it was Si: Mo: O: N = 40: 8: 7: 45 (atomic% ratio).

On the phase shift film, a light shielding film made of tantalum and nitrogen was formed to a thickness of 28 nm using a DC sputtering apparatus. The target was tantalum, and the sputtering gas was xenon and nitrogen. When the composition of this light shielding film was analyzed by ESCA, it was Ta: N = 85: 15 (atomic% ratio).

On this light shielding film, an etching mask film made of chromium, oxygen and nitrogen was formed to a thickness of 18 nm using a DC sputtering apparatus. The target was chromium, and the sputtering gas was argon, oxygen, and nitrogen. When the composition of this etching mask film was analyzed by ESCA, it was Cr: O: N = 45: 45: 10 (atomic% ratio). Further, the optical density (OD value) at the exposure wavelength (193 nm) of the ArF excimer laser in which the etching mask film, the light shielding film and the phase shift film were combined was measured with a spectrophotometer and found to be 3.2.

Thus, a phase shift mask blank in which a phase shift film made of silicon, molybdenum, oxygen and nitrogen, a light shielding film made of tantalum and nitrogen, and an etching mask film made of chrome, oxygen and nitrogen are laminated on a quartz substrate. Obtained.

Next, a negative chemically amplified electron beam resist is spin-coated on this etching mask film to a film thickness of 150 nm, the pattern is drawn with an electron beam at a dose of 35 μC / cm ² , heat-treated at 110 ° C. for 10 minutes, and paddle development is performed. Was developed for 90 seconds to form a resist pattern. When the resolution of this resist pattern was compared with a resist pattern obtained by performing the same treatment on an etching mask film of a silicon compound treated with HMDS, it was confirmed that the collapse of the resist pattern was improved by 10 nm.

Next, the etching mask film was patterned using a dry etching apparatus. The etching gas was chlorine, oxygen, and helium, the gas pressure was set to 5 mTorr, the ICP power was set to 400 W, and the bias power was set to 40 W. Next, the resist pattern was stripped and washed by sulfuric acid water washing.

Next, the light shielding film was patterned using a dry etching apparatus. The etching gas was chlorine and helium, the gas pressure was set to 5 mTorr, the ICP power was set to 400 W, and the bias power was set to 40 W. After the dry etching process, an undercut in which the line pattern dimension of the lower light shielding film becomes thinner than the upper etching mask film did not occur.

Next, the phase shift film was patterned using a dry etching apparatus. The etching gas was CF ₄ and oxygen, the gas pressure was set to 5 mTorr, the ICP power was set to 400 W, and the bias power was set to 20 W. Dry etching was stopped when the quartz substrate was dug in an average of 2 nm.

Next, a positive resist film was spin-coated and drawn by a laser drawing apparatus. Thereafter, development was performed to form a resist pattern.

Next, the etching mask film was removed using a dry etching apparatus. The etching gas was chlorine, oxygen, and helium, the gas pressure was set to 10 mTorr, the ICP power was set to 500 W, and the bias power was set to 10 W. Over-etching was performed at 200%.

Next, the light shielding film was removed using a dry etching apparatus. The etching gas was chlorine and helium, the gas pressure was set to 10 mTorr, the ICP power was set to 500 W, and the bias power was set to 10 W. Over-etching was performed at 200%.

Next, the resist pattern was peeled and washed by washing with sulfuric acid to obtain a phase shift mask. When the transmittance and phase difference of this phase shift mask were measured with MPM193 manufactured by Lasertec Corporation, the transmittance of the phase shift film portion with respect to the transmittance of the quartz substrate at the exposure wavelength (193 nm) of the ArF excimer laser was 6.1%. The phase difference was 180 degrees. Further, when the pattern roughness dependency of the pattern dimension of the phase shift mask was compared with a phase shift mask using a conventional silicon compound film as an etching mask film, an improvement of 2 nm was confirmed. Further, when a plurality of phase shift masks were produced and the probability of the residue of the etching mask film and the light shielding film being generated in the defect inspection was investigated, it was 5% of the phase shift mask using a conventional silicon compound film as the etching mask film. Confirmed to improve.

Next, a positive resist film was spin-coated on the phase shift mask of this example in which the residue of the etching mask film and the light shielding film was detected by defect inspection, and writing was performed only around the residue portion by a laser drawing apparatus. . Thereafter, development was performed to form a resist pattern having openings only around the residue.

Next, the residue of the etching mask film was removed using a dry etching apparatus. The etching gas was chlorine, oxygen, and helium, the gas pressure was set to 10 mTorr, the ICP power was set to 500 W, and the bias power was set to 10 W. Over-etching was performed at 200%.

Next, the residue of the light shielding film was removed using a dry etching apparatus. The etching gas was chlorine and helium, the gas pressure was set to 10 mTorr, the ICP power was set to 500 W, and the bias power was set to 10 W. Over-etching was performed at 200%.

Next, the resist pattern was peeled and washed by washing with sulfuric acid, and the residue correction of the etching mask film and the light shielding film of the phase shift mask of this example was completed. When this phase shift mask was inspected for defects, it was confirmed that the residues of the etching mask film and the light shielding film were completely removed.

(Example 2)
A phase shift film made of silicon, molybdenum, oxygen and nitrogen was formed to a thickness of 66 nm on a quartz substrate using a DC sputtering apparatus using two targets. The target was molybdenum and silicon, and the sputtering gas was argon, oxygen, and nitrogen. When the composition of this phase shift film was analyzed by ESCA, it was Si: Mo: O: N = 40: 8: 7: 45 (atomic% ratio).

On the phase shift film, an ion sputtering apparatus was used to form a lower light-shielding film made of ruthenium with a thickness of 10 nm. The target was ruthenium, and the sputtering gas was xenon. When the composition of this light-shielding film was analyzed by ESCA, Ru = 100 (atomic% ratio).

An upper light-shielding film made of tantalum and nitrogen was formed on the lower light-shielding film with a thickness of 18 nm using a DC sputtering apparatus. The target was tantalum, and the sputtering gas was xenon and nitrogen. When the composition of this light shielding film was analyzed by ESCA, it was Ta: N = 85: 15 (atomic% ratio).

Thus, a phase shift film made of silicon, molybdenum, oxygen and nitrogen, a lower light shielding film made of ruthenium, an upper light shielding film made of tantalum and nitrogen, and an etching mask film made of chromium, oxygen and nitrogen are formed on the quartz substrate. A laminated phase shift mask blank was obtained.

Next, the upper light shielding film was patterned using a dry etching apparatus. The etching gas was chlorine and helium, the gas pressure was set to 5 mTorr, the ICP power was set to 400 W, and the bias power was set to 40 W. After the dry etching process, an undercut in which the dimension of the line pattern of the upper light-shielding film is narrower than the upper etching mask film did not occur.

Next, the lower light shielding film was patterned using a dry etching apparatus. The etching gas was oxygen and helium, the gas pressure was set to 5 mTorr, the ICP power was set to 400 W, and the bias power was set to 40 W. After the dry etching process, an undercut in which the dimension of the line pattern of the lower light-shielding film was narrower than that of the upper light-shielding film did not occur.

Next, the upper light shielding film was removed using a dry etching apparatus. The etching gas was chlorine and helium, the gas pressure was set to 10 mTorr, the ICP power was set to 500 W, and the bias power was set to 10 W. Over-etching was performed at 200%.

Next, the lower light shielding film was removed using a dry etching apparatus. The etching gas was oxygen and helium, the gas pressure was set to 10 mTorr, the ICP power was set to 500 W, and the bias power was set to 10 W. Over-etching was performed at 200%.

Next, the resist pattern was peeled and washed by washing with sulfuric acid to obtain a phase shift mask. When the transmittance and phase difference of this phase shift mask were measured with MPM193 manufactured by Lasertec Corporation, the transmittance of the phase shift film portion with respect to the transmittance of the quartz substrate at the exposure wavelength (193 nm) of the ArF excimer laser was 6.1%. The phase difference was 180 degrees. Further, when the pattern roughness dependency of the pattern dimension of the phase shift mask was compared with a phase shift mask using a conventional silicon compound film as an etching mask film, an improvement of 2 nm was confirmed. Further, when a plurality of phase shift masks were produced and the probability of the residue of the etching mask film and the light shielding film being generated in the defect inspection was examined, it was 7% of the phase shift mask using the conventional silicon compound film as the etching mask film. Confirmed to improve. Since the upper light-shielding film is thinner, the improvement rate is higher than that of Example 1.

Next, a positive resist film is spin-coated on the phase shift mask of this embodiment in which the residues of the etching mask film, the upper light shielding film, and the lower light shielding film are detected by defect inspection, and only the vicinity of the residue portion is formed by a laser drawing apparatus. Draw on. Thereafter, development was performed to form a resist pattern having openings only around the residue.

Next, the residue of the upper light shielding film was removed using a dry etching apparatus. The etching gas was chlorine and helium, the gas pressure was set to 10 mTorr, the ICP power was set to 500 W, and the bias power was set to 10 W. Over-etching was performed at 200%.

Next, the residue of the lower light shielding film was removed using a dry etching apparatus. The etching gas was oxygen and helium, the gas pressure was set to 10 mTorr, the ICP power was set to 500 W, and the bias power was set to 10 W. Over-etching was performed at 200%.

(Example 3)
A phase shift film made of silicon and nitrogen was formed to a thickness of 68 nm on a quartz substrate using a DC sputtering apparatus. The target was silicon, and the sputtering gas was argon and nitrogen. When the composition of this phase shift film was analyzed by ESCA, it was Si: N = 50: 50 (atomic% ratio).

On the phase shift film, a light shielding film made of tantalum and nitrogen was formed to a thickness of 26 nm using a DC sputtering apparatus. The target was tantalum, and the sputtering gas was xenon and nitrogen. When the composition of this light shielding film was analyzed by ESCA, it was Ta: N = 70: 30 (atomic% ratio). Further, the optical density (OD value) at the exposure wavelength (193 nm) of the ArF excimer laser obtained by combining the light-shielding film and the phase shift film was measured with a spectrophotometer and found to be 2.9.

An etching mask film made of chromium and nitrogen was formed to a thickness of 13 nm on this light shielding film using a DC sputtering apparatus. The target was chromium, and the sputtering gas was argon and nitrogen. When the composition of this etching mask film was analyzed by ESCA, it was Cr: N = 90: 10 (atomic% ratio).

Thus, a phase shift mask blank was obtained in which a phase shift film made of silicon and nitrogen, a light shielding film made of tantalum and nitrogen, and an etching mask film made of chromium and nitrogen were laminated on a quartz substrate.

Next, the resist pattern was peeled and washed by washing with sulfuric acid to obtain a phase shift mask. When the transmittance and phase difference of this phase shift mask were measured with MPM193 manufactured by Lasertec Corporation, the transmittance of the phase shift film portion with respect to the transmittance of the quartz substrate at the exposure wavelength (193 nm) of the ArF excimer laser was 5.5%. The phase difference was 180 degrees. Further, when the pattern roughness dependence of the pattern dimension of this phase shift mask was compared with a phase shift mask using a conventional silicon compound film as an etching mask film, an improvement of 3 nm was confirmed. Further, when a plurality of phase shift masks were produced and the probability of the residue of the etching mask film and the light shielding film being generated in the defect inspection was investigated, it was 5% of the phase shift mask using a conventional silicon compound film as the etching mask film. Confirmed to improve.

Example 4
A phase shift film made of silicon and nitrogen was formed to a thickness of 61 nm on a quartz substrate using a DC sputtering apparatus. The target was silicon, and the sputtering gas was argon and nitrogen. When the composition of this phase shift film was analyzed by ESCA, it was Si: N = 50: 50 (atomic% ratio).

On the phase shift film, a lower light-shielding film made of a ruthenium compound was formed to a thickness of 17 nm using an ion sputtering apparatus. The target was ruthenium, and the sputtering gas was xenon and nitrogen. When the composition of this light shielding film was analyzed by ESCA, it was Ru: N = 95: 5 (atomic% ratio).

An upper light-shielding film made of tantalum and nitrogen was formed to a thickness of 10 nm on the lower light-shielding film using a DC sputtering apparatus. The target was tantalum, and the sputtering gas was xenon and nitrogen. When the composition of this upper light shielding film was analyzed by ESCA, it was Ta: N = 70: 30 (atomic% ratio). Further, the optical density (OD value) at the exposure wavelength (193 nm) of the ArF excimer laser obtained by combining the light-shielding film and the phase shift film was measured with a spectrophotometer and found to be 2.9.

In this way, a phase shift film made of silicon and nitrogen, a lower light shielding film made of ruthenium compound, an upper light shielding film made of tantalum and nitrogen, and an etching mask film made of chromium and nitrogen are laminated on the quartz substrate. A mask blank was obtained.

Next, the upper light shielding film was patterned using a dry etching apparatus. The etching gas was CF ₄ and helium, the gas pressure was set to 5 mTorr, the ICP power was set to 400 W, and the bias power was set to 20 W. After the dry etching process, an undercut in which the dimension of the line pattern of the upper light-shielding film is narrower than the upper etching mask film did not occur.

Next, the upper light shielding film was removed using a dry etching apparatus. The etching gas was CF ₄ and helium, the gas pressure was set to 5 mTorr, the ICP power was set to 400 W, and the bias power was set to 20 W. Overetching was stopped when an average of 18 nm was dug into the quartz substrate. Thus, a desired phase difference can be realized in combination with the thickness of the phase shift film being 61 nm.

Next, the resist pattern was peeled and washed by washing with sulfuric acid to obtain a phase shift mask. When the transmittance and phase difference of this phase shift mask were measured with MPM193 manufactured by Lasertec Corporation, the transmittance of the phase shift film portion relative to the transmittance of the quartz substrate at the exposure wavelength (193 nm) of the ArF excimer laser was 7.4%, The phase difference was 180 degrees. Further, when the pattern roughness dependence of the pattern dimension of this phase shift mask was compared with a phase shift mask using a conventional silicon compound film as an etching mask film, an improvement of 3 nm was confirmed. Further, when a plurality of phase shift masks were produced and the probability of the residue of the etching mask film and the light shielding film being generated in the defect inspection was investigated, the phase shift mask was 9% of the phase shift mask using a conventional silicon compound film as an etching mask film. Confirmed to improve. Since the upper light-shielding film is thinner, the improvement rate is higher than that in Example 3.

(Example 5)
A first phase shift film made of silicon, molybdenum, oxygen and nitrogen was formed to a thickness of 62 nm on a quartz substrate using a DC sputtering apparatus using two targets. The target was molybdenum and silicon, and the sputtering gas was argon, oxygen, and nitrogen. When the composition of this phase shift film was analyzed by ESCA, it was Si: Mo: O: N = 40: 8: 7: 45 (atomic% ratio). Subsequently, a second phase shift film made of silicon and oxygen was formed to a thickness of 10 nm on the first phase shift film using a DC sputtering apparatus. The target was silicon, and the sputtering gas was argon and oxygen. When the composition of this phase shift film was analyzed by ESCA, it was Si: O = 33: 67 (atomic% ratio).

On this light shielding film, an etching mask film made of chromium, oxygen and nitrogen was formed to a thickness of 18 nm using a DC sputtering apparatus. The target was chromium, and the sputtering gas was argon, oxygen, and nitrogen. When the composition of this etching mask film was analyzed by ESCA, it was Cr: O: N = 45: 45: 10 (atomic% ratio). Further, the optical density (OD value) at the exposure wavelength (193 nm) of the ArF excimer laser including the etching mask film, the light shielding film and the phase shift film was measured with a spectrophotometer and found to be 3.1.

Thus, on the quartz substrate, the first phase shift film made of silicon, molybdenum, oxygen and nitrogen, the second phase shift film made of silicon and oxygen, the light shielding film made of tantalum and nitrogen, chromium and oxygen A phase shift mask blank on which an etching mask film made of nitrogen was laminated was obtained.

Next, the first and second phase shift films were patterned using a dry etching apparatus. The etching gas was CF ₄ and oxygen, the gas pressure was set to 5 mTorr, the ICP power was set to 400 W, and the bias power was set to 20 W. Dry etching was stopped when the quartz substrate was dug in an average of 2 nm.

Next, the resist pattern was peeled and washed by washing with sulfuric acid to obtain a phase shift mask. When the transmittance and phase difference of this phase shift mask were measured with MPM193 manufactured by Lasertec Corporation, the transmittance of the phase shift film portion with respect to the transmittance of the quartz substrate at the exposure wavelength (193 nm) of ArF excimer laser was 7.2%, The phase difference was 180 degrees. Further, when the pattern roughness dependency of the pattern dimension of the phase shift mask was compared with a phase shift mask using a conventional silicon compound film as an etching mask film, an improvement of 2 nm was confirmed. Further, when a plurality of phase shift masks were produced and the probability of the residue of the etching mask film and the light shielding film being generated in the defect inspection was investigated, it was 5% of the phase shift mask using a conventional silicon compound film as the etching mask film. Confirmed to improve.

Next, the residue of the light shielding film was removed using a dry etching apparatus. The etching gas was chlorine and helium, the gas pressure was set to 10 mTorr, the ICP power was set to 500 W, and the bias power was set to 60 W. It has been confirmed by prior evaluation that the quartz substrate is damaged by 2 nm under this etching condition.

Next, the resist pattern was peeled and washed by washing with sulfuric acid, and the residue correction of the etching mask film and the light shielding film of the phase shift mask of this example was completed. When this phase shift mask was inspected for defects, it was confirmed that the residues of the etching mask film and the light shielding film were completely removed. Moreover, when the transmittance | permeability and phase difference of this phase shift mask were measured with MPM193 by Lasertec, it confirmed that it was not changing from the value before residue correction.

(Example 6)
A first phase shift film made of silicon, molybdenum, oxygen and nitrogen was formed to a thickness of 62 nm on a quartz substrate using a DC sputtering apparatus using two targets. The target was molybdenum and silicon, and the sputtering gas was argon, oxygen, and nitrogen. When the composition of this phase shift film was analyzed by ESCA, it was Si: Mo: O: N = 40: 8: 7: 45 (atomic% ratio). Subsequently, a second phase shift film made of silicon and oxygen was formed to a thickness of 10 nm on the first phase shift film using a DC sputtering apparatus. The target was silicon, and the sputtering gas was argon and oxygen. When the composition of this phase shift film was analyzed by ESCA, it was Si: O = 33: 67 (atomic% ratio).

On the phase shift film, a lower light-shielding film made of a ruthenium compound was formed to a thickness of 5 nm using an ion sputtering apparatus. The target was ruthenium, and the sputtering gas was xenon and boron. When the composition of this light shielding film was analyzed by ESCA, it was Ru: B = 80: 20 (atomic% ratio).

An upper light-shielding film made of tantalum and nitrogen was formed to a thickness of 24 nm on the lower light-shielding film using a DC sputtering apparatus. The target was tantalum, and the sputtering gas was xenon and nitrogen. When the composition of this light shielding film was analyzed by ESCA, it was Ta: N = 85: 15 (atomic% ratio).

Thus, on the quartz substrate, the first phase shift film made of silicon, molybdenum, oxygen and nitrogen, the second phase shift film made of silicon and oxygen, the lower light shielding film made of ruthenium compound, and the tantalum and nitrogen Thus obtained was a phase shift mask blank in which an upper light shielding film and an etching mask film made of chromium, oxygen and nitrogen were laminated.

Next, the resist pattern was peeled and washed by washing with sulfuric acid to obtain a phase shift mask. When the transmittance and phase difference of this phase shift mask were measured with MPM193 manufactured by Lasertec Corporation, the transmittance of the phase shift film portion with respect to the transmittance of the quartz substrate at the exposure wavelength (193 nm) of ArF excimer laser was 7.2%, The phase difference was 180 degrees. Further, when the pattern roughness dependency of the pattern dimension of the phase shift mask was compared with a phase shift mask using a conventional silicon compound film as an etching mask film, an improvement of 2 nm was confirmed. Further, when a plurality of the phase shift masks were produced and the probability of the residue of the etching mask film and the light shielding film being generated in the defect inspection was investigated, it was 6% of the phase shift mask using the conventional silicon compound film as the etching mask film. Confirmed to improve. Since the upper light-shielding film is thinner, the improvement rate is higher than that in Example 5.

(Example 7)
A phase shift film made of silicon, molybdenum, oxygen and nitrogen was formed to a thickness of 59 nm on a quartz substrate using a DC sputtering apparatus using two targets. The target was molybdenum and silicon, and the sputtering gas was argon, oxygen, and nitrogen. When the composition of this phase shift film was analyzed by ESCA, it was Si: Mo: O: N = 40: 8: 7: 45 (atomic% ratio).

On the phase shift film, a light shielding film made of tantalum and nitrogen was formed to a thickness of 20 nm using a DC sputtering apparatus. The target was tantalum, and the sputtering gas was xenon and nitrogen. When the composition of this light shielding film was analyzed by ESCA, it was Ta: N = 85: 15 (atomic% ratio).

An antireflection film made of tantalum and oxygen was formed to a thickness of 10 nm on the light shielding film using a DC sputtering apparatus. The target was tantalum, and the sputtering gas was xenon and oxygen. When the composition of this light shielding film was analyzed by ESCA, it was Ta: O = 35: 65 (atomic% ratio). Further, the optical density (OD value) at the exposure wavelength (193 nm) of the ArF excimer laser in which the antireflection film, the light shielding film and the phase shift film were combined was measured with a spectrophotometer and found to be 3.0.

An etching mask film made of chromium and nitrogen was formed to a thickness of 13 nm on this antireflection film using a DC sputtering apparatus. The target was chromium, and the sputtering gas was argon and nitrogen. When the composition of this etching mask film was analyzed by ESCA, it was Cr: N = 90: 10 (atomic% ratio).

Thus, a phase shift film made of silicon, molybdenum, oxygen and nitrogen, a light shielding film made of tantalum and nitrogen, an antireflection film made of tantalum and oxygen, and an etching mask film made of chromium and nitrogen are laminated on the quartz substrate. A phase shift mask blank was obtained.

Next, the antireflection film was patterned using a dry etching apparatus. The etching gas was CF ₄ and oxygen, the gas pressure was set to 5 mTorr, the ICP power was set to 400 W, and the bias power was set to 20 W. Dry etching was stopped when the light shielding film was dug in an average of 5 nm.

Next, the light shielding film was patterned using a dry etching apparatus. The etching gas was chlorine and helium, the gas pressure was set to 5 mTorr, the ICP power was set to 400 W, and the bias power was set to 40 W. After the dry etching process, an undercut in which the line pattern dimensions of the lower anti-reflection film and the light-shielding film were reduced with respect to the upper etching mask film did not occur.

Next, the antireflection film was removed using a dry etching apparatus. The etching gas was CF ₄ and oxygen, the gas pressure was set to 5 mTorr, the ICP power was set to 400 W, and the bias power was set to 20 W. Dry etching was stopped when the quartz substrate was dug in an average of 15 nm.

Next, the resist pattern was peeled and washed by washing with sulfuric acid to obtain a phase shift mask. When the transmittance and phase difference of this phase shift mask were measured with MPM193 manufactured by Lasertec Corporation, the transmittance of the phase shift film portion relative to the transmittance of the quartz substrate at the exposure wavelength (193 nm) of the ArF excimer laser was 8.1%. The phase difference was 180 degrees. Further, when the pattern roughness dependence of the pattern dimension of this phase shift mask was compared with a phase shift mask using a conventional silicon compound film as an etching mask film, an improvement of 3 nm was confirmed. Further, when a plurality of phase shift masks were produced and the probability of the residue of the etching mask film and the light shielding film being generated in the defect inspection was examined, it was 7% of the phase shift mask using the conventional silicon compound film as the etching mask film. Confirmed to improve.

Next, before the above-described etching mask film removal step, particles made of Si ₃ N ₄ are distributed on the mask surface, the etching mask film removal step is performed, and the particles are intentionally removed by washing. An etching mask film residue was generated on the antireflection film. Next, a reflection mask inspection was performed, and it was confirmed that this residue was detected. Next, the residue of the etching mask film was removed using a dry etching apparatus. The etching gas was chlorine, oxygen, and helium, the gas pressure was set to 10 mTorr, the ICP power was set to 500 W, and the bias power was set to 10 W. Overetching was performed 100%. Next, when the detected residue generation region was observed with SEM, it was confirmed that the residue was completely removed.

(Example 8)
A phase shift film made of silicon, molybdenum, oxygen and nitrogen was formed to a thickness of 59 nm on a quartz substrate using a DC sputtering apparatus using two targets. The target was molybdenum and silicon, and the sputtering gas was argon, oxygen, and nitrogen. When the composition of this phase shift film was analyzed by ESCA, it was Si: Mo: O: N = 40: 8: 7: 45 (atomic% ratio).

An underlayer light-shielding film made of a ruthenium compound was formed to a thickness of 10 nm on this phase shift film using an ion sputtering apparatus. The target was ruthenium / niobium alloy, and the sputtering gas was xenon. When the composition of the light shielding film was analyzed by ESCA, it was Ru: Nb = 85: 15 (atomic% ratio).

An upper light-shielding film made of tantalum and nitrogen was formed to a thickness of 12 nm on the lower light-shielding film using a DC sputtering apparatus. The target was tantalum, and the sputtering gas was xenon and nitrogen. When the composition of this light shielding film was analyzed by ESCA, it was Ta: N = 85: 15 (atomic% ratio).

Thus, a phase shift film made of silicon, molybdenum, oxygen and nitrogen, a lower light shielding film made of ruthenium compound, an upper light shielding film made of tantalum and nitrogen, an antireflection film made of tantalum and oxygen, and chromium on a quartz substrate. And a phase shift mask blank in which an etching mask film made of nitrogen was laminated.

Next, the upper light shielding film was patterned using a dry etching apparatus. The etching gas was chlorine and helium, the gas pressure was set to 5 mTorr, the ICP power was set to 400 W, and the bias power was set to 40 W. After the dry etching process, an undercut in which the line pattern dimensions of the lower anti-reflection film and the upper light-shielding film were reduced with respect to the upper etching mask film did not occur.

Next, the resist pattern was peeled and washed by washing with sulfuric acid to obtain a phase shift mask. When the transmittance and phase difference of this phase shift mask were measured with MPM193 manufactured by Lasertec Corporation, the transmittance of the phase shift film portion relative to the transmittance of the quartz substrate at the exposure wavelength (193 nm) of the ArF excimer laser was 8.1%. The phase difference was 180 degrees. Further, when the pattern roughness dependence of the pattern dimension of this phase shift mask was compared with a phase shift mask using a conventional silicon compound film as an etching mask film, an improvement of 3 nm was confirmed. Further, when a plurality of phase shift masks were prepared and the probability that residues of the etching mask film and the light shielding film were generated in the defect inspection was investigated, the phase shift mask was 8% of the phase shift mask using a conventional silicon compound film as an etching mask film. Confirmed to improve. Since the upper light-shielding film is thinner, the improvement rate is higher than that in Example 7.

Example 9
A phase shift film made of silicon and nitrogen was formed to a thickness of 64 nm on a quartz substrate using a DC sputtering apparatus. The target was silicon, and the sputtering gas was argon and nitrogen. When the composition of this phase shift film was analyzed by ESCA, it was Si: N = 50: 50 (atomic% ratio).

A light-shielding film made of tantalum, nitrogen, and oxygen was formed to a thickness of 30 nm on the phase shift film using a DC sputtering apparatus. The target was tantalum, and the sputtering gas was xenon, nitrogen, and oxygen. When the composition of this light shielding film was analyzed by ESCA, it was Ta: N: O = 85: 10: 5 (atomic% ratio).

An antireflection film made of tantalum and oxygen was formed to a thickness of 6 nm on the light shielding film using a DC sputtering apparatus. The target was tantalum, and the sputtering gas was xenon and oxygen. When the composition of this light shielding film was analyzed by ESCA, it was Ta: O = 30: 70 (atomic% ratio). Further, the optical density (OD value) at the exposure wavelength (193 nm) of the ArF excimer laser in which the antireflection film, the light shielding film and the phase shift film were combined was measured with a spectrophotometer and found to be 3.0.

On this antireflection film, an etching mask film made of chromium and nitrogen was formed to a thickness of 4 nm using a DC sputtering apparatus. The target was chromium, and the sputtering gas was argon and nitrogen. When the composition of this etching mask film was analyzed by ESCA, it was Cr: N = 90: 10 (atomic% ratio).

Thus, the phase shift film made of silicon and nitrogen, the light shielding film made of tantalum, nitrogen and oxygen, the antireflection film made of tantalum and oxygen, and the etching mask film made of chromium and nitrogen were laminated on the quartz substrate. A phase shift mask blank was obtained.

Next, a negative chemically amplified electron beam resist is spin-coated at a film thickness of 80 nm on this etching mask film, the pattern is drawn with an electron beam at a dose of 37 μC / cm ² , heat-treated at 110 ° C. for 10 minutes, and paddle development is performed. Development was performed for 60 seconds to form a resist pattern. When the resolution of this resist pattern was compared with a resist pattern obtained by performing the same treatment on an etching mask film of a silicon compound treated with HMDS, it was confirmed that the collapse of the resist pattern was improved by 10 nm.

Next, the phase shift film was patterned using a dry etching apparatus. The etching gas was CF ₄ and oxygen, the gas pressure was set to 5 mTorr, the ICP power was set to 400 W, and the bias power was set to 20 W. Dry etching was stopped when the quartz substrate was dug 1 nm on average.

Next, the antireflection film was removed using a dry etching apparatus. The etching gas was CF ₄ and oxygen, the gas pressure was set to 5 mTorr, the ICP power was set to 400 W, and the bias power was set to 20 W. Dry etching was stopped when the quartz substrate was dug on average 8 nm.

Next, the resist pattern was peeled and washed by washing with sulfuric acid to obtain a phase shift mask. When the transmittance and phase difference of this phase shift mask were measured with MPM193 manufactured by Lasertec Corporation, the transmittance of the phase shift film part relative to the transmittance of the quartz substrate at the exposure wavelength (193 nm) of the ArF excimer laser was 6.8%, The phase difference was 180 degrees. Further, when the pattern roughness dependence of the pattern dimension of this phase shift mask was compared with a phase shift mask using a conventional silicon compound film as an etching mask film, an improvement of 4 nm was confirmed. Further, when a plurality of phase shift masks were produced and the probability of the residue of the etching mask film and the light shielding film being generated in the defect inspection was investigated, it was found to be 3% of the phase shift mask using a conventional silicon compound film as the etching mask film. Confirmed to improve.

(Example 10)
A phase shift film made of silicon and nitrogen was formed to a thickness of 64 nm on a quartz substrate using a DC sputtering apparatus. The target was silicon, and the sputtering gas was argon and nitrogen. When the composition of this phase shift film was analyzed by ESCA, it was Si: N = 50: 50 (atomic% ratio).

An underlayer light-shielding film made of a ruthenium compound was formed to a thickness of 10 nm on this phase shift film using an ion sputtering apparatus. The target was ruthenium, and the sputtering gas was xenon and nitrogen. When the composition of this light shielding film was analyzed by ESCA, it was Ru: N = 80: 20 (atomic% ratio).

On the lower light-shielding film, an upper light-shielding film made of tantalum, nitrogen and oxygen was formed to a thickness of 23 nm using a DC sputtering apparatus. The target was tantalum, and the sputtering gas was xenon, nitrogen, and oxygen. When the composition of this light shielding film was analyzed by ESCA, it was Ta: N: O = 85: 10: 5 (atomic% ratio).

Thus, a phase shift film made of silicon and nitrogen, a lower light shielding film made of a ruthenium compound, an upper light shielding film made of tantalum, nitrogen and oxygen, an antireflection film made of tantalum and oxygen, and chromium and nitrogen. A phase shift mask blank on which an etching mask film made of was laminated was obtained.

Next, the resist pattern was peeled and washed by washing with sulfuric acid to obtain a phase shift mask. When the transmittance and phase difference of this phase shift mask were measured with MPM193 manufactured by Lasertec Corporation, the transmittance of the phase shift film part relative to the transmittance of the quartz substrate at the exposure wavelength (193 nm) of the ArF excimer laser was 6.8%, The phase difference was 180 degrees. Further, when the pattern roughness dependence of the pattern dimension of this phase shift mask was compared with a phase shift mask using a conventional silicon compound film as an etching mask film, an improvement of 4 nm was confirmed. Further, when a plurality of phase shift masks were produced and the probability of the residue of the etching mask film and the light shielding film being generated in the defect inspection was investigated, it was 5% of the phase shift mask using a conventional silicon compound film as the etching mask film. Confirmed to improve. Since the upper light-shielding film is thinner, the improvement rate is higher than that in Example 9.

(Example 11)
A phase shift film made of silicon and oxygen was formed to a thickness of 169 nm using an RF sputtering apparatus using two targets on a quartz substrate. The target was silicon, and the sputtering gas was argon and oxygen. When the composition of this phase shift film was analyzed by ESCA, it was Si: O = 33: 67 (atomic% ratio).

On the phase shift film, a light shielding film made of tantalum and nitrogen was formed to a thickness of 48 nm using a DC sputtering apparatus. The target was tantalum, and the sputtering gas was xenon and nitrogen. When the composition of this light shielding film was analyzed by ESCA, it was Ta: N = 85: 15 (atomic% ratio). Further, the optical density (OD value) at the exposure wavelength (193 nm) of the ArF excimer laser in which the etching mask film, the light shielding film, and the phase shift film were combined was measured with a spectrophotometer and found to be 2.9.

An etching mask film made of chromium, nitrogen and carbon was formed to a thickness of 10 nm on the light shielding film using a DC sputtering apparatus. The target was chromium, and the sputtering gas was argon, nitrogen, and carbon. When the composition of this etching mask film was analyzed by ESCA, it was Cr: N: C = 85: 10: 5 (atomic% ratio).

In this way, a phase shift mask blank was obtained in which a phase shift film made of silicon and oxygen, a light shielding film made of tantalum and nitrogen, and an etching mask film made of chromium, nitrogen and carbon were laminated on a quartz substrate.

Next, a negative chemically amplified electron beam resist is spin-coated on the etching mask film at a film thickness of 120 nm, a pattern is drawn with an electron beam at a dose of 36 μC / cm ² , heat-treated at 110 ° C. for 10 minutes, and paddle development is performed. Then, development was performed for 70 seconds to form a resist pattern. When the resolution of this resist pattern was compared with a resist pattern obtained by performing the same treatment on an etching mask film of a silicon compound treated with HMDS, it was confirmed that the collapse of the resist pattern was improved by 10 nm.

Next, the phase shift film was patterned using a dry etching apparatus. The etching gas was CF ₄ and oxygen, the gas pressure was set to 5 mTorr, the ICP power was set to 400 W, and the bias power was set to 20 W. Dry etching was stopped when the quartz substrate was dug 2 nm on average.

Next, the resist pattern was peeled and washed by washing with sulfuric acid to obtain a phase shift mask. When the transmittance and phase difference of this phase shift mask were measured with MPM193 manufactured by Lasertec Corporation, the transmittance of the phase shift film portion with respect to the transmittance of the quartz substrate at the exposure wavelength (193 nm) of ArF excimer laser was 98%, and the phase difference Was 180 degrees. Further, when the phase difference of the phase shift mask was measured over the entire surface of the mask, it was confirmed that no phase difference error due to pattern dependency or mask position dependency occurred. In addition, when a program defect portion where a black defect of the phase shift film was intentionally arranged was corrected with an electron beam, it was confirmed that it could be corrected with a good shape. Further, when the pattern roughness dependency of the pattern dimension of the phase shift mask was compared with a phase shift mask using a conventional silicon compound film as an etching mask film, an improvement of 2 nm was confirmed. In addition, when a plurality of phase shift masks were prepared and the probability of the residue of the etching mask film and the light shielding film being generated in the defect inspection was investigated, it was found to be 2% of the phase shift mask using a conventional silicon compound film as an etching mask film. Confirmed to improve.

(Example 12)
A phase shift film made of silicon and oxygen was formed to a thickness of 169 nm using an RF sputtering apparatus using two targets on a quartz substrate. The target was silicon, and the sputtering gas was argon and oxygen. When the composition of this phase shift film was analyzed by ESCA, it was Si: O = 33: 67 (atomic% ratio).

On the phase shift film, a lower light shielding film made of a ruthenium compound was formed to a thickness of 20 nm using an ion sputtering apparatus. The target was ruthenium, and the sputtering gas was xenon and nitrogen. When the composition of this light shielding film was analyzed by ESCA, it was Ru: N = 90: 10 (atomic% ratio).

An upper light-shielding film made of tantalum and nitrogen was formed to a thickness of 32 nm on the lower light-shielding film using a DC sputtering apparatus. The target was tantalum, and the sputtering gas was xenon and nitrogen. When the composition of this light shielding film was analyzed by ESCA, it was Ta: N = 85: 15 (atomic% ratio). Further, the optical density (OD value) at the exposure wavelength (193 nm) of the ArF excimer laser in which the etching mask film, the light shielding film, and the phase shift film were combined was measured with a spectrophotometer and found to be 2.9.

In this manner, a phase shift film made of silicon and oxygen, a lower light shielding film made of a ruthenium compound, an upper light shielding film made of tantalum and nitrogen, and an etching mask film made of chromium, nitrogen and carbon are laminated on the quartz substrate. A phase shift mask blank was obtained.

Next, the resist pattern was peeled and washed by washing with sulfuric acid to obtain a phase shift mask. When the transmittance and phase difference of this phase shift mask were measured with MPM193 manufactured by Lasertec Corporation, the transmittance of the phase shift film portion with respect to the transmittance of the quartz substrate at the exposure wavelength (193 nm) of ArF excimer laser was 98%, and the phase difference Was 180 degrees. Further, when the phase difference of the phase shift mask was measured over the entire surface of the mask, it was confirmed that no phase difference error due to pattern dependency or mask position dependency occurred. In addition, when a program defect portion where a black defect of the phase shift film was intentionally arranged was corrected with an electron beam, it was confirmed that it could be corrected with a good shape. Further, when the pattern roughness dependency of the pattern dimension of the phase shift mask was compared with a phase shift mask using a conventional silicon compound film as an etching mask film, an improvement of 2 nm was confirmed. Further, when a plurality of phase shift masks were prepared and the probability of the residue of the etching mask film and the light shielding film being generated in the defect inspection was investigated, it was 4% of the phase shift mask using a conventional silicon compound film as the etching mask film. Confirmed to improve. Since the upper light-shielding film is thin, the improvement rate is higher than that of Example 11.

(Example 13)
A first phase shift film made of silicon, molybdenum, oxygen and nitrogen was formed to a thickness of 56 nm on a quartz substrate using a DC sputtering apparatus using two targets. The target was molybdenum and silicon, and the sputtering gas was argon, oxygen, and nitrogen. When the composition of this phase shift film was analyzed by ESCA, it was Si: Mo: O: N = 40: 8: 7: 45 (atomic% ratio). Subsequently, a second phase shift film made of silicon and oxygen was formed to a thickness of 8 nm on the first phase shift film using a DC sputtering apparatus. The target was silicon, and the sputtering gas was argon and oxygen. When the composition of this phase shift film was analyzed by ESCA, it was Si: O = 33: 67 (atomic% ratio).

An antireflection film made of tantalum and oxygen was formed to a thickness of 10 nm on the light shielding film using a DC sputtering apparatus. The target was tantalum, and the sputtering gas was xenon and oxygen. When the composition of this light shielding film was analyzed by ESCA, it was Ta: O = 35: 65 (atomic% ratio). Further, the optical density (OD value) at the exposure wavelength (193 nm) of the ArF excimer laser in which the antireflection film, the light shielding film and the phase shift film were combined was measured with a spectrophotometer and found to be 2.9.

Thus, the first phase shift film made of silicon, molybdenum, oxygen and nitrogen, the second phase shift film made of silicon and oxygen, the light shielding film made of tantalum and nitrogen, and the tantalum and oxygen are formed on the quartz substrate. A phase shift mask blank in which an antireflection film and an etching mask film made of chromium and nitrogen were laminated was obtained.

Next, the resist pattern was peeled and washed by washing with sulfuric acid to obtain a phase shift mask. When the transmittance and phase difference of this phase shift mask were measured with MPM193 manufactured by Lasertec Corporation, the transmittance of the phase shift film portion with respect to the transmittance of the quartz substrate at the exposure wavelength (193 nm) of the ArF excimer laser was 9.3%. The phase difference was 180 degrees. Further, when the pattern roughness dependence of the pattern dimension of this phase shift mask was compared with a phase shift mask using a conventional silicon compound film as an etching mask film, an improvement of 3 nm was confirmed. Further, when a plurality of phase shift masks were produced and the probability of the residue of the etching mask film and the light shielding film being generated in the defect inspection was examined, it was 7% of the phase shift mask using the conventional silicon compound film as the etching mask film. Confirmed to improve.

Next, a phase shift mask in which additional dry etching was added after the above-described light shielding film removal step was produced. The added dry etching gas was chlorine and helium, the gas pressure was set to 10 mTorr, the ICP power was set to 500 W, and the bias power was set to 60 W. It has been confirmed by prior evaluation that the quartz substrate is damaged by 2 nm under this etching condition. When the transmittance and phase difference of this phase shift mask were measured by MPM193 manufactured by Lasertec, it was confirmed that there was no fluctuation from the value of the phase shift mask not subjected to additional dry etching.

(Example 14)
A first phase shift film made of silicon, molybdenum, oxygen and nitrogen was formed to a thickness of 56 nm on a quartz substrate using a DC sputtering apparatus using two targets. The target was molybdenum and silicon, and the sputtering gas was argon, oxygen, and nitrogen. When the composition of this phase shift film was analyzed by ESCA, it was Si: Mo: O: N = 40: 8: 7: 45 (atomic% ratio). Subsequently, a second phase shift film made of silicon and oxygen was formed to a thickness of 8 nm on the first phase shift film using a DC sputtering apparatus. The target was silicon, and the sputtering gas was argon and oxygen. When the composition of this phase shift film was analyzed by ESCA, it was Si: O = 33: 67 (atomic% ratio).

On this lower light shielding film, an upper light shielding film made of tantalum and nitrogen was formed to a thickness of 11 nm using a DC sputtering apparatus. The target was tantalum, and the sputtering gas was xenon and nitrogen. When the composition of this light shielding film was analyzed by ESCA, it was Ta: N = 85: 15 (atomic% ratio). Further, the optical density (OD value) at the exposure wavelength (193 nm) of the ArF excimer laser in which the etching mask film, the light shielding film, and the phase shift film were combined was measured with a spectrophotometer and found to be 2.9.

Thus, on the quartz substrate, the first phase shift film made of silicon, molybdenum, oxygen and nitrogen, the second phase shift film made of silicon and oxygen, the lower light shielding film made of ruthenium alloy, and the tantalum and nitrogen A phase shift mask blank was obtained in which an upper light shielding film, an antireflection film made of tantalum and oxygen, and an etching mask film made of chromium and nitrogen were laminated.

Next, the resist pattern was peeled and washed by washing with sulfuric acid to obtain a phase shift mask. When the transmittance and phase difference of this phase shift mask were measured with MPM193 manufactured by Lasertec Corporation, the transmittance of the phase shift film portion with respect to the transmittance of the quartz substrate at the exposure wavelength (193 nm) of the ArF excimer laser was 9.3%. The phase difference was 180 degrees. Further, when the pattern roughness dependence of the pattern dimension of this phase shift mask was compared with a phase shift mask using a conventional silicon compound film as an etching mask film, an improvement of 3 nm was confirmed. Further, when a plurality of phase shift masks were prepared and the probability that residues of the etching mask film and the light shielding film were generated in the defect inspection was investigated, the phase shift mask was 8% of the phase shift mask using a conventional silicon compound film as an etching mask film. Confirmed to improve. Since the upper light-shielding film is thinner, the improvement rate is higher than that in Example 13.

In the present invention, since the composition and film thickness and layer structure of the phase shift mask blank and the manufacturing process and conditions of the phase shift mask using the phase shift mask were selected within an appropriate range, a logic system device of 28 nm or less, or 30 nm or less It is possible to provide a phase shift mask in which a fine pattern is formed with high accuracy corresponding to memory device manufacturing.

10, 20: phase shift mask blank, 11, 21: substrate (substrate transparent to exposure wavelength), 12, 22: phase shift film, 13, 23: light shielding film or upper light shielding film, 14, 24: etching mask Film, 15, 25: Resist pattern, 16, 26: Second resist pattern, 13a: Residue (residue of upper light shielding film), 14a: Residue (residue of etching mask film), 18a: Residue (residue of lower light shielding film) ), 17: resist pattern, 18, 28: lower light shielding layer, 100, 200: phase shift mask, 10 ′: phase shift mask blank, 11 ′: substrate (substrate transparent to exposure wavelength), 12 ′: phase Shift film, 13 ′: light shielding film or upper light shielding film, 14 ′: antireflection film, 15 ′: etching mask film, 16 ′: resist pattern, 17 ′: second resist pattern Emissions, 18 ': lower shielding layer, 100': phase shift mask

Claims

A phase shift mask blank in which a phase shift film, a light shielding film, and an etching mask film are laminated in this order on a substrate transparent to an exposure wavelength,
The phase shift film is resistant to oxygen-containing chlorine-based etching (Cl / O-based) and non-oxygen-containing chlorine-based etching (Cl-based), and can be etched by fluorine-based etching (F-based). ,
The light-shielding film is resistant to oxygen-containing chlorine-based etching (Cl / O-based) and can be etched by non-oxygen-containing chlorine-based etching (Cl-based).
The etching mask film is resistant to fluorine-based etching (F-based) and non-oxygen-containing chlorine-based etching (Cl-based), and can be etched by oxygen-containing chlorine-based etching (Cl / O-based). ,
Not having an etching stopper layer between the phase shift film and the substrate;
A phase shift mask blank characterized by that.
The light shielding film is made of a tantalum compound not containing silicon, and the tantalum compound not containing silicon contains at least one selected from nitrogen, boron, oxygen and carbon in addition to tantalum.
The phase shift mask blank according to claim 1.
The light shielding film is mainly composed of tantalum nitride,
The phase shift mask blank according to claim 2.
The etching mask film contains at least one selected from nitrogen, oxygen and carbon in addition to chromium alone or chromium.
The phase shift mask blank according to any one of claims 1 to 3, wherein:
The phase shift film has a function of giving a predetermined amount of phase change to transmitted exposure light, contains silicon, and contains at least one selected from transition metals, nitrogen, oxygen and carbon,
The transition metal is at least one selected from molybdenum, titanium, vanadium, cobalt, nickel, zirconium, niobium, and hafnium.
The phase shift mask blank according to any one of claims 1 to 4, wherein the phase shift mask blank is provided.
Between the light shielding film and the etching mask film, it has resistance to oxygen-containing chlorine-based etching (Cl / O system) and non-oxygen-containing chlorine-based etching (Cl system), and fluorine-based etching (F system). The antireflection film that can be etched with is laminated,
The phase shift mask blank according to claim 1, wherein the phase shift mask blank is provided.
The antireflection film is mainly composed of tantalum oxide,
The phase shift mask blank according to claim 6.
A phase shift mask blank in which a phase shift film, a lower light shielding film, an upper light shielding film, and an etching mask film are laminated in this order on a substrate transparent to the exposure wavelength,
The phase shift film has resistance to oxygen-containing chlorine-based etching (Cl / O-based), non-oxygen-containing chlorine-based etching (Cl-based), and oxygen-based etching (O-based), and fluorine-based etching ( F system) can be etched,
The lower light-shielding film has resistance to fluorine-based etching (F-based) and non-oxygen-containing chlorine-based etching (Cl-based), and can be etched by oxygen-based etching (O-based).
The upper light-shielding film is resistant to oxygen-containing chlorine-based etching (Cl / O-based) and is both fluorine-based etching (F-based) and non-oxygen-containing chlorine-based etching (Cl-based) or any one of them. It can be etched on one side,
The etching mask film is resistant to fluorine-based etching (F-based), non-oxygen-containing chlorine-based etching (Cl-based), and oxygen-based etching (O-based), and oxygen-containing chlorine-based etching (Cl / O-based) can be etched,
A phase shift mask blank characterized by that.
The lower light-shielding film has a thickness of 2 nm or more and 30 nm or less, and is formed of ruthenium alone or a ruthenium compound having a ruthenium content of 50 atomic% or more.
The phase shift mask blank according to claim 8.
The phase shift mask blank according to claim 8 or 9, wherein the upper light shielding film is made of a tantalum compound or a silicon compound.
The phase shift mask blank according to claim 10, wherein the tantalum compound contains tantalum and at least one selected from nitrogen, boron, silicon, oxygen, and carbon.
The silicon compound contains silicon and contains one or more selected from molybdenum, titanium, vanadium, cobalt, nickel, zirconium, niobium, hafnium, nitrogen, oxygen, and carbon. The described phase shift mask blank.
The etching mask film contains at least one selected from nitrogen, oxygen and carbon in addition to chromium alone or chromium.
The phase shift mask blank according to any one of claims 8 to 12, wherein
The phase shift film has a function of giving a predetermined amount of phase change to transmitted exposure light, contains silicon, and contains at least one selected from transition metals, nitrogen, oxygen and carbon,
The transition metal is at least one selected from molybdenum, titanium, vanadium, cobalt, nickel, zirconium, niobium, and hafnium.
The phase shift mask blank according to any one of claims 8 to 13,
Resistant to oxygen-containing chlorine-based etching (Cl / O-based) and non-oxygen-containing chlorine-based etching (Cl-based) and fluorine-based etching (F-based) between the upper light shielding film and the etching mask film ) An anti-reflective film that can be etched in
The phase shift mask blank according to claim 8, wherein:
The antireflection film is mainly composed of tantalum oxide,
The phase shift mask blank according to claim 15, wherein:
A portion of the film of the phase shift mask blank in which a plurality of films including a phase shift film, a light shielding film, and an etching mask film are laminated in this order on a substrate transparent to the exposure wavelength is selectively A phase shift mask in which a circuit pattern is formed by being removed,
The phase shift film is resistant to oxygen-containing chlorine-based etching (Cl / O-based) and non-oxygen-containing chlorine-based etching (Cl-based), and can be etched by fluorine-based etching (F-based). ,
The light-shielding film is resistant to oxygen-containing chlorine-based etching (Cl / O-based) and can be etched by non-oxygen-containing chlorine-based etching (Cl-based).
The etching mask film is resistant to fluorine-based etching (F-based) and non-oxygen-containing chlorine-based etching (Cl-based), and can be etched by oxygen-containing chlorine-based etching (Cl / O-based). ,
Not having an etching stopper layer between the phase shift film and the substrate;
A phase shift mask characterized by that.
The light shielding film is made of a tantalum compound not containing silicon, and the tantalum compound not containing silicon contains at least one selected from nitrogen, boron, oxygen and carbon in addition to tantalum.
The phase shift mask according to claim 17.
The light shielding film is mainly composed of tantalum nitride,
The phase shift mask according to claim 18.
The etching mask film contains at least one selected from nitrogen, oxygen and carbon in addition to chromium alone or chromium.
The phase shift mask according to any one of claims 17 to 19, wherein the phase shift mask is provided.
The phase shift film has a function of giving a predetermined amount of phase change to transmitted exposure light, contains silicon, and contains at least one selected from transition metals, nitrogen, oxygen and carbon,
The transition metal is at least one selected from molybdenum, titanium, vanadium, cobalt, nickel, zirconium, niobium, and hafnium.
The phase shift mask according to any one of claims 17 to 20, wherein
Between the light shielding film and the etching mask film, it has resistance to oxygen-containing chlorine-based etching (Cl / O system) and non-oxygen-containing chlorine-based etching (Cl system), and fluorine-based etching (F system). The antireflection film that can be etched with is laminated,
The phase shift mask according to any one of claims 17 to 21, wherein the phase shift mask is provided.
The antireflection film is mainly composed of tantalum oxide,
The phase shift mask according to claim 22, wherein
A part of the film of the phase shift mask blank in which the phase shift film, the lower layer light shielding film, the upper layer light shielding film, and the etching mask film are laminated in this order on the substrate transparent to the exposure wavelength is selective. A phase shift mask in which a circuit pattern is formed by being removed,
The phase shift film has resistance to oxygen-containing chlorine-based etching (Cl / O-based), non-oxygen-containing chlorine-based etching (Cl-based), and oxygen-based etching (O-based), and fluorine-based etching ( F system) can be etched,
The lower light-shielding film has resistance to fluorine-based etching (F-based) and non-oxygen-containing chlorine-based etching (Cl-based), and can be etched by oxygen-based etching (O-based).
The upper light-shielding film is resistant to oxygen-containing chlorine-based etching (Cl / O-based) and is both fluorine-based etching (F-based) and non-oxygen-containing chlorine-based etching (Cl-based) or any one of them. It can be etched on one side,
The etching mask film is resistant to fluorine-based etching (F-based), non-oxygen-containing chlorine-based etching (Cl-based), and oxygen-based etching (O-based), and oxygen-containing chlorine-based etching (Cl / O-based) can be etched,
A phase shift mask characterized by that.
The lower light-shielding film has a thickness of 2 nm or more and 30 nm or less, and is formed of ruthenium alone or a ruthenium compound having a ruthenium content of 50 atomic% or more.
25. The phase shift mask according to claim 24, wherein:
The phase shift mask according to claim 24 or 25, wherein the upper light shielding film is made of a tantalum compound or a silicon compound.
The phase shift mask according to claim 26, wherein the tantalum compound contains tantalum and at least one selected from nitrogen, boron, silicon, oxygen, and carbon.
The silicon compound contains silicon and contains at least one selected from molybdenum, titanium, vanadium, cobalt, nickel, zirconium, niobium, hafnium, nitrogen, oxygen, and carbon. The phase shift mask as described.
The etching mask film contains at least one selected from nitrogen, oxygen and carbon in addition to chromium alone or chromium.
The phase shift mask according to any one of claims 24 to 28, wherein:
The phase shift film has a function of giving a predetermined amount of phase change to transmitted exposure light, contains silicon, and contains at least one selected from transition metals, nitrogen, oxygen and carbon,
The transition metal is at least one selected from molybdenum, titanium, vanadium, cobalt, nickel, zirconium, niobium, and hafnium.
30. A phase shift mask according to any one of claims 24 to 29, wherein:
Resistant to oxygen-containing chlorine-based etching (Cl / O-based) and non-oxygen-containing chlorine-based etching (Cl-based) and fluorine-based etching (F-based) between the upper light shielding film and the etching mask film ) An anti-reflective film that can be etched in
The phase shift mask according to any one of claims 24 to 30, wherein:
The antireflection film is mainly composed of tantalum oxide,
The phase shift mask according to claim 31, wherein:
A method of manufacturing a phase shift mask using the phase shift mask blank according to any one of claims 1 to 7,
Forming a resist pattern on the etching mask film;
Forming a pattern on the etching mask film by oxygen-containing chlorine-based etching (Cl / O system);
A step of forming a pattern on the light shielding film by non-oxygen-containing chlorine-based etching (Cl-based) and fluorine-based etching (F-based), or any one of them;
Forming a pattern on the phase shift film by fluorine etching (F system);
Removing the etching mask film from the pattern formed on the light shielding film by oxygen-containing chlorine-based etching (Cl / O system);
The light shielding film is removed from the pattern formed on the phase shift film by non-oxygen-containing chlorine-based etching (Cl-based) or both non-oxygen-containing chlorine-based etching (Cl-based) and fluorine-based etching (F-based). Including a process,
A method of manufacturing a phase shift mask.
A correction step of removing only the residue of the etching mask film generated on the light shielding film by oxygen-containing chlorine-based etching (Cl / O system), and removing only the residue of the light shielding film generated on the phase shift film. Including any one of the correction steps to be removed by oxygen-containing chlorine-based etching (Cl-based),
The method of manufacturing a phase shift mask according to claim 33, wherein:
A phase shift mask manufacturing method using the phase shift mask blank according to any one of claims 8 to 16,
Forming a resist pattern on the etching mask film;
Forming a pattern on the etching mask film by oxygen-containing chlorine-based etching (Cl / O system);
A step of forming a pattern on the upper light-shielding film by both or one of non-oxygen-containing chlorine-based etching (Cl-based) and fluorine-based etching (F-based);
Forming a pattern on the lower light-shielding film by oxygen-based etching (O-based);
Forming a pattern on the phase shift film by fluorine etching (F system);
Removing the etching mask film from the pattern formed on the upper light shielding film by oxygen-containing chlorine-based etching (Cl / O system);
Removing the upper light shielding film from the pattern formed on the lower light shielding film by non-oxygen-containing chlorine-based etching (Cl-based) and fluorine-based etching (F-based), or any one of them;
Removing the lower light-shielding film from the pattern formed on the phase shift film by oxygen-based etching (O-based).
A method of manufacturing a phase shift mask.
A correction step of removing only the residue of the etching mask film generated on the upper light shielding film by oxygen-containing chlorine-based etching (Cl / O system), and only the residue of the upper light shielding film generated on the lower light shielding film Any of a correction step of removing oxygen by chlorine-free etching (Cl-based) and a correction step of removing only the residue of the lower light shielding film generated on the phase shift film by oxygen-based etching (O-based) Including one,
36. A method of manufacturing a phase shift mask according to claim 35, wherein: