JP5639778B2 - Mask blank, transfer mask, and manufacturing method thereof - Google Patents

Description

  The present invention relates to a mask blank and a transfer mask with improved light resistance, and a method for manufacturing them. In particular, the present invention relates to a mask blank and a transfer mask for manufacturing a transfer mask that is suitably used in an exposure apparatus that uses exposure light having a short wavelength of 200 nm or less as an exposure light source, and a manufacturing method thereof.

  In general, in a manufacturing process of a semiconductor device, a fine pattern is formed using a photolithography method. Further, a number of substrates called transfer masks are usually used for forming this fine pattern. This transfer mask is generally provided with a fine pattern made of a metal thin film on a translucent glass substrate, and the photolithographic method is also used in the production of this transfer mask.

  In manufacturing a transfer mask by photolithography, a mask blank having a thin film (for example, a light shielding film) for forming a transfer pattern (mask pattern) on a light-transmitting substrate such as a glass substrate is used. In the manufacture of a transfer mask using this mask blank, an exposure process for drawing a desired pattern on the resist film formed on the mask blank, and developing the resist film in accordance with the desired pattern drawing, the resist pattern is developed. The development step is formed, the etching step is to etch the thin film in accordance with the resist pattern, and the step is to remove and remove the remaining resist pattern. In the developing step, a desired pattern is drawn on the resist film formed on the mask blank, and then a developing solution is supplied to dissolve a portion of the resist film that is soluble in the developing solution, thereby forming a resist pattern. . Further, in the above etching process, using this resist pattern as a mask, the exposed portion of the thin film on which the resist pattern is not formed is dissolved by dry etching or wet etching, whereby the desired mask pattern is formed on the translucent substrate. Form. Thus, a transfer mask is completed.

  When miniaturizing a pattern of a semiconductor device, it is necessary to shorten the wavelength of an exposure light source used in photolithography in addition to miniaturization of a mask pattern formed on a transfer mask. In recent years, as an exposure light source for manufacturing semiconductor devices, the wavelength has been shortened from an KrF excimer laser (wavelength 248 nm) to an ArF excimer laser (wavelength 193 nm).

  As a type of transfer mask, a halftone phase shift mask is known in addition to a binary mask having a light-shielding film pattern made of a chromium-based material on a conventional translucent substrate. This halftone type phase shift mask has a structure having a phase shift film on a translucent substrate, and this phase shift film has a light intensity that does not substantially contribute to exposure (for example, 1 for the exposure wavelength). % To 20%) and is a light semi-transmissive film having a predetermined phase difference. For example, a material containing a molybdenum silicide compound is used. This halftone type phase shift mask includes a phase shift unit patterned with a phase shift film, and a light transmission unit that does not have a phase shift film and transmits light having an intensity that substantially contributes to exposure. The phase of the light transmitted through the light transmission part is substantially inverted with respect to the phase of the light transmitted through the light transmission part, so that the light passes through the vicinity of the boundary between the phase shift part and the light transmission part and is diffractive. Thus, the lights that have entered each other's area cancel each other out, and the light intensity at the boundary is made almost zero, thereby improving the contrast of the boundary, that is, the resolution. As a material of this phase shift film, a molybdenum silicide compound which is a material containing molybdenum and silicon is widely used.

In addition, there is a special type of light semi-transmissive film mainly used as a thin film for forming an enhancer mask pattern. The light semi-transmissive portion formed of the light semi-transmissive film transmits exposure light with a predetermined transmittance, but unlike the halftone phase shift film, the phase of the exposure light transmitted through the light semi-transmissive portion is light. It has substantially the same phase with the exposure light transmitted through the transmission part. As the material of the light semi-transmissive film, a molybdenum silicide compound, which is a material containing molybdenum and silicon, is widely used.
In recent years, binary masks using a molybdenum silicide compound as a light-shielding film have also appeared.

JP 2002-156742 A JP 2002-258455 A

  However, with the recent shortening of the exposure light source wavelength, mask deterioration due to repeated use of a transfer mask has become prominent. In particular, in the case of a phase shift mask, the ArF excimer laser (wavelength: 193 nm) irradiation of the exposure light source causes a change in transmittance and phase difference, and further a phenomenon that the line width changes (thickens). In the case of a phase shift mask, such changes in transmittance and phase difference are important problems that affect the mask performance. When the change in transmittance increases, the transfer accuracy deteriorates, and when the change in phase difference increases, the phase shift effect at the pattern boundary becomes difficult to obtain, the contrast at the pattern boundary decreases, and the resolution decreases greatly. End up. Further, the line width change also deteriorates the CD accuracy of the transfer mask, and finally the CD accuracy of the transferred wafer.

  The problem of mask deterioration due to repeated use of a transfer mask is particularly a phase shift mask in which a compound of a transition metal and a silicon-containing material (transition metal silicide) is used as a material of a light semi-transmissive film such as a halftone type phase shift film. In the enhancer mask in which a compound of a material containing transition metal and silicon is used as the material of the light semi-transmissive film, the transmittance change, phase difference change, line width change (thickness) of the light semi-transmissive film is also remarkable. The problem of deterioration of CD accuracy has occurred. Further, even in a binary mask having a light-shielding film made of a material containing transition metal and silicon or a compound thereof, there is a problem of deterioration of CD accuracy related to a line width change (thickness) of the light-shielding film.

  According to the study by the present inventor, the background of the problem of mask deterioration due to repeated use of such a transfer mask is presumed as follows. Conventionally, for example, when haze is generated, cleaning is performed to remove the haze, but film reduction (elution) due to cleaning is unavoidable, and the number of times of cleaning determines the mask life. However, since the number of cleanings has been reduced due to the recent improvement in haze, the repeated use period of the mask has been extended, and the exposure time has also been extended accordingly. It was.

  Conventionally, in order to suppress changes in transmittance and phase difference due to exposure light irradiation of the phase shift film, for example, a phase shift film mainly composed of metal and silicon is 250 to 350 ° C. in the air or in an oxygen atmosphere. Heat treatment for 90 to 150 minutes (for example, Patent Document 1 above), or forming a cap layer mainly composed of metal and silicon on a phase shift film mainly composed of metal and silicon (for example, Patent Document 1 described above). 2) was done. However, in the case of heat treatment using an oven or a hot plate as described in Patent Document 1, not only the pattern forming thin film but also the temperature of the light-transmitting substrate varies. That is, the temperature rises from the periphery of the translucent substrate during heating, and the cooling starts from the periphery of the translucent substrate during cooling. As a result, the in-plane uniformity of the optical characteristics of the pattern forming thin film is lowered. As the exposure light source has been shortened in recent years, there is a demand for further improvement in light resistance of the film with respect to exposure light, which is excellent in in-plane uniformity of the thin film for pattern formation.

  Accordingly, the present invention has been made to solve the above-described problems, and an object of the present invention is to form a pattern forming thin film (light semi-transmissive) made of a material containing a transition metal and silicon with respect to exposure light having a wavelength of 200 nm or less. Masks that improve the light resistance of the transfer pattern, prevent changes in the line width of the transfer pattern (thickness of the line width), improve the life of the transfer mask, and have excellent in-plane uniformity of the pattern forming thin film It is to provide a method for manufacturing a blank and a transfer mask.

  The inventor presumed the following factors that caused the deterioration of the transfer mask due to repeated use as the exposure light source wavelength became shorter. In addition, as described in the Examples, the present invention has been clarified from the results of experiments by the inventors of the present invention that the effects of the present invention can be obtained by having the predetermined configuration of the present invention. It is not bound by the speculation described below.

As a result of examining a halftone phase shift film pattern of a halftone phase shift mask made of a MoSi-based material in which transmittance and phase difference change are caused by repeated use, the present inventor found that Si and Si on the surface layer side of the MoSi-based film It has been found that an altered layer containing O and some Mo is formed, which is one of the main causes of changes in transmittance, retardation, and line width (thickening). And the reason (mechanism) which such an altered layer arises is considered as follows. In other words, the conventional sputter-deposited MoSi-based film (phase shift film) has a structural gap, and even when annealed after film formation, the change in the structure of the MoSi film is small. For example, ozone (O ₃ ) generated when oxygen (O ₂ ), water (H ₂ O), oxygen (O ₂ ) in the atmosphere reacts with the ArF excimer laser enters the gap, and the phase shift film Reacts with Si and Mo constituting That is, Si and Mo constituting the phase shift film in such an environment are excited and become a transition state when irradiated with exposure light (especially, short wavelength light such as ArF), and Si is oxidized and expanded (SiO rather than Si). together for ₂ volume is large), Mo also altered layer is produced on the surface layer side of the phase shift film is oxidized. And by repeatedly using the phase shift mask, when the exposure light is accumulated, the oxidation and expansion of Si further progress, and the oxidized Mo diffuses in the altered layer and precipitates on the surface, for example, It is considered that MoO ₃ is sublimated, and as a result, the thickness of the deteriorated layer gradually increases (the proportion of the deteriorated layer in the MoSi film increases). The phenomenon in which such an altered layer is generated and further expanded is that the energy required for the transition of the constituent atoms that trigger the oxidation reaction of Si and Mo constituting the phase shift film to occur. This is remarkably confirmed in the case of exposure light having a short wavelength such as an ArF excimer laser. Such a phenomenon is not limited to MoSi-based materials, and the same can be said for phase shift films made of materials containing other transition metals and silicon. The same applies to an enhancer mask having a light semi-transmissive film made of a material containing transition metal and silicon and a binary mask having a light-shielding film made of a material containing transition metal and silicon.

  Further, the present inventor has found that by performing a flame treatment on the pattern forming thin film, the temperature of the pattern forming thin film itself increases, but the temperature increase of the translucent substrate can be suppressed. Since only the pattern forming thin film can be heated by the flame treatment, it is possible to perform a process excellent in in-plane uniformity of the pattern forming thin film without being affected by the temperature change of the translucent substrate.

  The present inventor completed the present invention as a result of further intensive studies based on the above elucidated facts and considerations. That is, in order to solve the above problems, the present invention has the following configuration.

  The present invention provides a method for manufacturing a mask blank having the following configurations 1 to 5, a mask blank having the following configuration 6, a transfer mask having the following configurations 7 and 9, and a transfer mask having the following configuration 8 Is the method.

(Configuration 1)
A method of manufacturing a mask blank including a pattern forming thin film on a light transmissive substrate, wherein the pattern forming thin film made of a material containing a transition metal and silicon is formed on the light transmissive substrate. And a step of flame-treating the pattern forming thin film. A method of manufacturing a mask blank, comprising:

(Configuration 2)
The mask blank manufacturing method according to Configuration 1, wherein the flame treatment includes scanning the entire surface of the pattern forming thin film while locally irradiating a flame.

(Configuration 3)
The mask blank manufacturing method according to Configuration 1 or 2, wherein the flame treatment includes irradiating a flame while measuring optical characteristics of the pattern forming thin film.

(Configuration 4)
It is a manufacturing method of the mask blank of any one of the structures 1-3 whose said optical characteristic is at least 1 selected from the transmittance | permeability and a reflectance.

(Configuration 5)
The pattern-forming thin film is a light semi-transmissive film made of a material mainly composed of a compound containing transition metal and silicon and one or more elements selected from oxygen and nitrogen, or a material containing at least a transition metal and silicon 5. A method for manufacturing a mask blank according to any one of configurations 1 to 4, wherein the mask blank is a light shielding film for binary mask.

(Configuration 6)
This invention is the mask blank manufactured by the manufacturing method of any one of the structures 1-5.

(Configuration 7)
The present invention is a transfer mask in which a transfer pattern is formed on the pattern forming thin film of the mask blank described in Structure 6.

(Configuration 8)
The present invention relates to a method for manufacturing a transfer mask having a transfer pattern on a translucent substrate, and a mask blank having a pattern forming thin film made of a material containing a transition metal and silicon on the translucent substrate. A transfer mask comprising: a preparing step; a step of forming a transfer pattern on the pattern forming thin film of the mask blank; and a step of flame-treating the pattern forming thin film on which the transfer pattern is formed. It is a manufacturing method.

(Configuration 9)
The present invention is a transfer mask manufactured by the manufacturing method according to Configuration 8.

  Next, configurations 1 to 5 of the mask blank manufacturing method of the present invention will be described.

  This invention is a manufacturing method of a mask blank provided with a thin film for pattern formation on a light-transmitting substrate as in Configuration 1, wherein a material containing a transition metal and silicon is formed on the light-transmitting substrate. A method of manufacturing a mask blank, comprising: forming a pattern forming thin film; and performing a flame treatment on the pattern forming thin film.

As in Configuration 1, in the mask blank manufacturing method of the present invention, the pattern forming thin film is flame-treated. The flame treatment is a treatment for irradiating a thin film for pattern formation with a flame. The generation mechanism of the altered layer in the thin film for pattern formation made of a material containing transition metal and silicon represented by MoSi film, etc. is as described above, but bonding of the thin film is suppressed so as to suppress oxidation of the transition metal and silicon. We focused on changing the structure itself, such as state and crystallinity. Therefore, as in Configuration 1, by performing a flame treatment on the pattern forming thin film, the entire pattern forming thin film made of a material containing transition metal and silicon is heated by heat conduction to change into a structure of the thin film itself such as a bonded state. Therefore, oxidation of transition metal and silicon can be suppressed. For example, in the case of a thin film for pattern formation containing Mo and Si, by performing a flame treatment, the Mo-Mo bond and the Si-Si bond in the thin film are decreased, and the Si-N bond and the Mo-Si bond are increased. I think that. Due to the structural change of the thin film itself, even if exposure light irradiation such as ArF excimer laser is performed on the transfer mask in an environment containing H ₂ O, O ₂ or O ₃ , Generation and expansion of the altered layer due to expansion can be effectively suppressed. Therefore, the transfer mask using the mask blank of the present invention is repeatedly used, and exposure light having a wavelength of 200 nm or less accumulates on the transfer pattern of the transfer mask using the mask blank manufactured by the manufacturing method of the present invention. Even when irradiated, the transfer characteristics of the transfer pattern, such as the transmittance and phase difference of a light semi-transmissive film such as a halftone type phase shift film, a change in line width (thickening of the line width), etc. can be suppressed. It is possible to suppress a decrease in the light shielding performance of the light shielding film, a change in line width (thickening of the line width), and the like. In addition, chemical resistance and moisture resistance are improved.

  Further, as described in Structure 2, in the mask blank manufacturing method of the present invention, it is preferable that the flame treatment includes scanning the entire surface of the pattern forming thin film while locally irradiating the flame.

  As in Configuration 2, by scanning the entire surface of the pattern forming thin film while locally irradiating a flame, the effect of the flame treatment can be uniformly exerted on the entire surface of the pattern forming thin film. In addition, it is possible to perform flame treatment (entire flame treatment) on the entire surface of the pattern forming thin film at once using an apparatus capable of generating a large flame. By performing the entire surface flame treatment, the flame treatment can be performed in a short time. However, since it is not easy to uniformly irradiate the entire surface of the pattern forming thin film with a large flame, there may be a problem in the uniformity of the flame treatment. Therefore, by using an apparatus that generates a relatively small flame and scanning the entire surface of the pattern forming thin film while locally irradiating the flame, the entire surface of the pattern forming thin film can be uniformly processed.

  Moreover, as it exists in the structure 3, it is preferable that the manufacturing method of the mask blank of this invention includes irradiating a flame, the said flame treatment measuring the optical characteristic of the said thin film for pattern formation.

  As in the configuration 3, the flame treatment can be evaluated immediately after the flame treatment by irradiating the flame while measuring the optical characteristics of the pattern forming thin film. Therefore, if the flame process is insufficient, a process with feedback, such as performing the flame process again, becomes possible. Therefore, by irradiating the flame while measuring the optical characteristics of the pattern forming thin film, the entire surface of the pattern forming thin film can be more uniformly processed. Note that the measurement of the optical characteristics includes measuring the place where the flame treatment is performed immediately after the flame treatment. Further, the measurement of the optical characteristics includes performing a place where the flame treatment is performed simultaneously with the flame treatment. In this case, incident light for measurement can be irradiated at an angle different from that of the flame of the flame treatment, for example, obliquely, and reflected light and / or transmitted light by the pattern forming thin film can be measured. .

  Further, as described in Structure 4, in the mask blank manufacturing method of the present invention, it is preferable that the optical characteristic is at least one selected from transmittance and reflectance.

  As in Configuration 4, when the optical characteristic is at least one selected from transmittance and reflectance, measurement can be easily performed with a known device. When the light semi-transmissive film is flame-treated, it is possible to measure either transmittance or reflectance. When the light shielding film for binary mask is subjected to flame treatment, the transmittance of the light shielding film is extremely small, so that the reflectance can be measured.

  Further, as described in Structure 5, in the method for producing a mask blank of the present invention, the pattern forming thin film is mainly composed of a compound in which one or more elements selected from oxygen and nitrogen are further contained in transition metal and silicon. A light semi-transmissive film made of a material as a component or a light shielding film for binary mask made of a material containing at least a transition metal and silicon is preferable. When a light semi-transmissive film or a binary mask light-shielding film is used as the pattern forming thin film, the transfer pattern directly affects the transfer characteristics when the transfer mask is produced. It is particularly preferable to perform a flame treatment on.

  This invention is the mask blank manufactured by the manufacturing method in any one of the said structures 1-5 as it exists in the structure 6. If the mask blank manufactured by the manufacturing method of any one of the above configurations 1 to 5 is used, even if the transfer mask is repeatedly used by using short wavelength light such as ArF excimer laser as an exposure light source, for example, a halftone phase It is possible to obtain a transfer mask that can suppress changes in transmittance, phase difference, line width, and the like of a light semi-transmissive film such as a shift film.

  The present invention is a transfer mask in which a transfer pattern is formed on the pattern forming thin film of the mask blank of the above configuration 6 as in the configuration 7. The transfer mask in which the transfer pattern is formed on the pattern forming thin film of the mask blank having the above-described configuration 6 can be used, for example, even when the transfer mask is repeatedly used with short wavelength light such as ArF as an exposure light source, for example, a halftone phase shift It is possible to suppress changes in transmittance, phase difference, line width, and the like of a light semi-transmissive film such as a film. In addition, the mask blank has improved chemical resistance and moisture resistance.

  The present invention is a method for manufacturing a transfer mask having a transfer pattern on a light-transmitting substrate as in Configuration 8, wherein the pattern formation is made of a material containing a transition metal and silicon on the light-transmitting substrate. A step of preparing a mask blank having a thin film for forming, a step of forming a transfer pattern on the thin film for pattern formation of the mask blank, and a step of performing a flame treatment on the thin film for pattern formation on which the transfer pattern is formed. A method for producing a transfer mask characterized by the above.

  As described in Structure 8, with the transfer mask manufacturing method of the present invention, a predetermined flame treatment can be performed after a predetermined transfer pattern is formed on a predetermined mask blank.

  As described in Structure 8, in the method for manufacturing a transfer mask according to the present invention, the entire pattern forming thin film made of a material containing transition metal and silicon is heated by subjecting the pattern forming thin film to a predetermined flame treatment. Since the structure of the thin film itself is changed by being heated by conduction, oxidation of the transition metal and silicon can be suppressed. For example, in the case of a thin film for pattern formation containing Mo and Si, by performing a flame treatment, the Mo-Mo bond and the Si-Si bond in the thin film are decreased, and the Si-N bond and the Mo-Si bond are increased. I think that. Therefore, the pattern forming thin film is repeatedly used by using short wavelength light of 200 nm or less, such as an ArF excimer laser, as an exposure light source, and exposure light having a wavelength of 200 nm or less is accumulated on the transfer pattern of the pattern forming thin film. However, it is possible to suppress the transfer characteristics of the transfer pattern, for example, the transmittance of the light semi-transmissive film such as the halftone type phase shift film, the change in phase difference, the change in line width, and the like. In addition, chemical resistance and moisture resistance are improved.

  The present invention is a transfer mask manufactured by the manufacturing method of Configuration 8 as described in Configuration 9. Even if the transfer mask manufactured by the manufacturing method of the above-described configuration 8 is repeatedly used by using short-wavelength light such as ArF as an exposure light source, for example, a translucent film such as a halftone phase shift film is used. Changes in transmittance, phase difference, line width, and the like can be suppressed. In addition, the mask blank has improved chemical resistance and moisture resistance.

  According to the method for manufacturing a mask blank having a pattern forming thin film on a light transmitting substrate of the present invention, the pattern forming thin film made of a material containing a transition metal and silicon is formed on the light transmitting substrate. By providing the film forming step and the step of flame-treating the pattern forming thin film, it is possible to suppress the formation of the altered layer on the surface of the pattern forming thin film. As a result, the light resistance of the pattern forming thin film (light semi-transmissive film, light-shielding film) made of a material containing transition metal and silicon with respect to exposure light having a wavelength of 200 nm or less is improved, and the change in the line width of the transfer pattern (line width) ) Can be prevented, the life of the transfer mask can be improved, and a mask blank and a transfer mask manufacturing method excellent in in-plane uniformity can be provided.

  Further, since a large-scale facility is not necessary for performing the flame treatment, the life of the transfer mask can be improved easily and at low cost.

It is a cross-sectional schematic diagram which shows an example of a mode that the mask blank is flame-treating. It is a cross-sectional schematic diagram which shows the process of manufacturing a phase shift mask using a mask blank. It is a schematic block diagram of an example of the flame treatment apparatus for performing a flame treatment, measuring a reflectance. It is a schematic block diagram of an example of the flame processing apparatus for performing a flame processing, measuring the transmittance | permeability. It is a schematic block diagram of an example of the flame treatment apparatus for performing a flame treatment, measuring the transmittance | permeability and / or the reflectance of the place which is performing a flame treatment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  The present invention relates to a method for manufacturing a mask blank to which ArF exposure light is applied and having a thin film for pattern formation on a translucent substrate, and a mask blank manufactured by the manufacturing method. The present invention also relates to a transfer mask in which a transfer pattern is formed on the pattern forming thin film of the mask blank. The present invention also relates to a method for manufacturing a transfer mask having a pattern forming thin film on which a transfer pattern is formed, and a transfer mask manufactured by the manufacturing method.

  The manufacturing method of the present invention is a manufacturing method of a mask blank provided with a pattern forming thin film on a translucent substrate, and a predetermined pattern forming thin film is formed, and the pattern forming thin film is flame-treated. And a process. Therefore, according to the manufacturing method of the present invention, since a thin film for pattern formation in which the structure of the thin film itself is changed can be obtained, even when the transfer mask is repeatedly used, generation of a deteriorated layer due to oxidation and expansion of Si, By effectively suppressing the enlargement, it is possible to prevent a change in the line width of the transfer pattern (thickening of the line width).

  Embodiments of a method for manufacturing a mask blank and a transfer mask according to the present invention will be described below. In the manufacturing method of the present invention, flame treatment is performed on the pattern forming thin film.

  The present invention is a method for manufacturing a mask blank having a thin film for pattern formation for forming a transfer pattern on a translucent substrate. In the production method of the present invention, a pattern forming thin film made of a material containing a transition metal and silicon is formed, and then the pattern forming thin film is subjected to a flame treatment. When the exposure light having a wavelength of 200 nm or less is accumulated and irradiated to the transfer pattern of the transfer mask produced by patterning the pattern forming thin film by the flame treatment, the transfer characteristics of the transfer pattern change more than a predetermined value. This can prevent the change in the line width of the transfer pattern (thickening of the line width).

  A translucent board | substrate will not be restrict | limited especially if it has transparency with respect to the exposure wavelength to be used. In the present invention, a quartz substrate and other various glass substrates (for example, soda lime glass, aluminosilicate glass, etc.) can be used. Among them, the quartz substrate is highly transparent in the wavelength region of the ArF excimer laser. It is particularly suitable for the present invention.

The pattern forming thin film for forming the transfer pattern is a thin film made of a material containing a transition metal and silicon, and will be described later in detail. For example, a halftone made of a material containing a compound of transition metal silicide (especially molybdenum silicide) is used. Examples thereof include a light semitransmissive film such as a mold phase shift film or a light shielding film.
As a method for forming a thin film for pattern formation on a translucent substrate, for example, a sputter film forming method is preferably mentioned, but the present invention is not limited to the sputter film forming method.

  The flame treatment is a treatment for irradiating the pattern forming thin film 2 with a flame. FIG. 1 shows a schematic cross-sectional view of an example of a state in which a mask blank 10 having a pattern forming thin film 2 on a translucent substrate 1 is subjected to flame treatment. The thin film 2 for pattern formation of the mask blank 10 is flame-treated by being heated by the flame 22 irradiated from the flame irradiation device 20. By performing a flame treatment on the pattern forming thin film 2, the entire pattern forming thin film 2 made of a material containing a transition metal and silicon is heated by heat conduction to change the structure of the thin film itself, such as a bonded state. It is possible to suppress the formation of a deteriorated layer on the surface of the thin film for use, and to prevent a change in the line width of the transfer pattern (thickening of the line width). Since only the pattern forming thin film 2 can be heated while suppressing the heating of the translucent substrate 1 by the flame treatment, the pattern forming thin film 2 having excellent in-plane uniformity of optical characteristics can be obtained. In addition, since a large-scale facility is not necessary for the flame treatment, the treatment by heating the pattern forming thin film 2 can be performed easily and at low cost.

As the flame irradiation device 20 for performing the flame treatment, a burner or the like that generates the flame 22 by burning flammable gas can be used. The flammable gas used in the flame irradiation apparatus 20 is preferably selected from hydrocarbons such as methane, propane, butane, and acetylene, hydrogen, and a mixed gas of oxygen and hydrogen. The use of a flammable gas such as a mixed gas of oxygen and hydrogen that can suppress the generation of H ₂ O by combustion is preferable because defects in the pattern forming thin film 2 can be reduced.

  The distance between the flame irradiation device 20 and the pattern forming thin film 2 during the flame treatment is appropriately selected within a range in which the generation of the flame 22 is not hindered and the irradiation of the flame 22 to the pattern forming thin film 2 is effectively performed. can do. The distance between the flame irradiation device 20 and the pattern forming thin film 2 during the flame treatment is preferably 10 mm to 40 mm from the standpoint of effectively performing the irradiation of the flame 22.

  The irradiation diameter of the flame 22 onto the pattern forming thin film 2 during the flame treatment differs depending on the flame generation diameter of the flame irradiation apparatus 20. When flame treatment (entire flame treatment) is performed on the entire surface of the pattern forming thin film 2 at once, the irradiation diameter of the flame 22 corresponding to the dimension of the pattern forming thin film 2 is required. By performing the whole surface flame treatment, it is possible to perform the flame treatment in a short time.

  Since it is not easy to uniformly irradiate the entire surface of the pattern forming thin film 2 with the large flame 22, the entire batch flame processing may cause a problem in processing uniformity. Therefore, by using an apparatus that generates a relatively small flame 22 and scanning the entire surface of the pattern forming thin film 2 while locally irradiating the flame 22, that is, by performing a scanning flame treatment, the entire surface of the pattern forming thin film 2 is scanned. Processing can be performed uniformly.

  When locally irradiating the flame 22 by the scanning flame treatment, the irradiation diameter of the flame 22 on the pattern forming thin film 2 is preferably 10 mm to 30 mm from the viewpoint of performing a uniform treatment locally. Moreover, when performing a scanning flame process, the flame irradiation apparatus 20 may be moved and the translucent board | substrate 1 which has the thin film 2 for pattern formation which is an irradiation object can also be moved. Moreover, the movement of the flame irradiation apparatus 20 or the translucent substrate 1 during the irradiation of the flame 22 can be continuously moved, or can be moved stepwise so as to repeat the movement and the stop.

  In the flame treatment used in the production method of the present invention, the temperature of the flame 22 is preferably in the range of 1000 to 1500 ° C., more preferably in the range of 1200 to 1300 ° C. By using the flame 22 in such a temperature range, the temperature of the pattern forming thin film 2 when the flame 22 is irradiated can be set to 650 ° C. or higher. It is considered that the temperature of the thin film for pattern formation 2 needs to be 650 ° C. or higher because the thin film 2 for pattern formation is considered to increase the Si—N bond around 600 ° C. Therefore, it is preferable that the temperature of the flame 22 is in the above range.

  In the flame treatment used in the manufacturing method of the present invention, when the flame irradiation device 20 or the translucent substrate 1 is moved stepwise in order to effectively perform the flame treatment of the pattern forming thin film 2, the flame for a predetermined place It is preferable to select the stop time of the flame irradiation apparatus 20 or the translucent substrate 1 so that the irradiation time of 22 is preferably 5 to 30 minutes, more preferably 10 to 15 minutes. Even when the flame irradiation apparatus 20 or the translucent substrate 1 is continuously moved, it is preferable that the flame 22 is continuously moved at a speed such that the irradiation time of the flame 22 with respect to a predetermined place falls within the above range.

  In the production method of the present invention, it is preferable to irradiate the flame 22 while measuring the optical characteristics of the pattern forming thin film 2 during the flame treatment. 3 to 5 are schematic configuration diagrams of a flame treatment apparatus 100 for performing flame treatment while measuring the optical characteristics of the pattern forming thin film 2. The flame treatment can be evaluated immediately after the flame treatment by irradiating the flame while measuring the optical characteristics of the pattern forming thin film. Therefore, if the flame treatment is insufficient, a process with feedback such as performing the flame treatment again becomes possible. Therefore, by irradiating the flame while measuring the optical characteristics of the pattern forming thin film, the entire surface of the pattern forming thin film can be more uniformly processed. When the flame irradiation device 20 or the translucent substrate 1 is moved stepwise, the optical characteristics can be measured when the flame irradiation device 20 or the translucent substrate 1 is stopped. Moreover, when moving the flame irradiation apparatus 20 or the translucent board | substrate 1 continuously, an optical characteristic can be measured continuously.

  Examples of optical characteristics measured during the flame treatment include reflectance, transmittance, absorption rate, and refractive index. Since it is possible to obtain an apparatus and a value can be obtained by a single measurement, it is preferable that the optical characteristic to be measured during the flame treatment is at least one selected from transmittance and reflectance. .

  Ultraviolet light (UV light) can be used as light used for measuring the optical characteristics of the pattern forming thin film 2. Visible light and infrared light can be used as light for measuring optical characteristics, but visible light and infrared light generated from the flame 22 during the flame treatment become noise during measurement, and the semiconductor device. Since the exposure light in this manufacturing process is ultraviolet light, it is preferable to use ultraviolet light. As a light source for generating ultraviolet light, a known ultraviolet light generating light source (UV light source), specifically, a deuterium lamp can be used. Moreover, what is used as exposure light in the manufacturing process of a semiconductor device can be used as light for measuring optical characteristics. Specifically, ArF excimer laser can be used as a UV light source, and ArF excimer laser light can be used as ultraviolet light.

  When the pattern forming thin film 2 is a light semi-transmissive film such as a halftone type phase shift film, transmittance and reflectance can be measured as optical characteristics. Further, when the pattern forming thin film 2 is an opaque binary mask light-shielding film, the reflectance can be measured as an optical characteristic.

  FIG. 3 shows an example of the structure of the flame treatment apparatus 100 used for the flame treatment of the pattern forming thin film 2. The mask blank 10 disposed on the stage 102 of the flame treatment apparatus 100 is flame-treated by being heated by the flame 22 irradiated from the flame irradiation apparatus 20, and the optical characteristics of the pattern forming thin film 2 (in FIG. 3). In the example, reflectance can be measured. In the flame processing apparatus 100 shown in FIG. 3, incident light 122 (ultraviolet light) is irradiated on the surface of the pattern forming thin film 2, and the amount of reflected light 126 reflected from the pattern forming thin film 2 is measured to thereby form a pattern. The reflectance of the forming thin film 2 is measured.

  In the example illustrated in FIG. 3, the flame processing apparatus 100 includes a stage 102, a UV light source unit 104, a UV light irradiation unit 106, a light receiving unit 108, a spectroscope 110, a stage controller 112, and a control unit 114. The stage 102 is a table that holds the mask blank 10 on the upper surface. The UV light source unit 104 is a light source that generates ultraviolet light. The UV light source unit 104 preferably generates deep ultraviolet light. In this example, the UV light source unit 104 is a deuterium lamp, and generates ultraviolet light having a wavelength of 190 to 400 nm, for example, according to an instruction from the control unit 114.

  The UV light irradiation unit 106 and the light receiving unit 108 are optical systems that face the surface of the pattern forming thin film 2 in the mask blank 10. The UV light irradiation unit 106 is connected to the UV light source unit 104 by an optical fiber, for example, and irradiates the surface of the pattern forming thin film 2 with ultraviolet light generated by the UV light source unit 104. The light receiving unit 108 receives the reflected light 126 from the pattern forming thin film 2.

  The spectroscope 110 is, for example, a fiber spectroscope, and receives and divides the reflected light 126 received by the light receiving unit 108 via an optical fiber or the like. In addition, the spectroscope 110 notifies the control unit 114 of the spectroscopic result. The stage controller 112 is a controller that moves the stage 102 relative to the UV light irradiation unit 106 and the light receiving unit 108, and moves the stage 102 in accordance with an instruction from the control unit 114, for example. Thereby, the stage controller 112 changes the position where the ultraviolet light is irradiated from the UV light irradiation unit 106 in the pattern forming thin film 2.

  The control unit 114 is a control device such as a PC, for example, and controls the operation of each unit of the flame processing apparatus 100. For example, in this example, the control unit 114 can measure the reflectance at a specific wavelength, for example, based on the spectral result received from the spectroscope 110. From the measured value of the reflectance, the degree of flame treatment at a predetermined place of the pattern forming thin film 2 can be evaluated.

  In FIG. 4, the schematic block diagram of the flame processing apparatus 100 for performing a flame processing, measuring the transmittance | permeability of the thin film 2 for pattern formation is shown. In the example of FIG. 4, unlike the example shown in FIG. Therefore, the transmitted light 124 transmitted through the pattern forming thin film 2 can be received by the light receiving unit 108. As a result, the transmittance of the pattern forming thin film 2 at a specific wavelength can be measured. From the measured value of the transmittance, the degree of flame treatment at a predetermined location of the pattern forming thin film 2 can be evaluated. In addition, it is also possible to measure a reflectance and a transmittance | permeability simultaneously by incorporating the measuring mechanism of the transmittance | permeability as shown in FIG. 4 in the example shown in FIG.

  In FIG. 5, the schematic block diagram of the flame processing apparatus 100 for performing a flame treatment, measuring the transmittance | permeability and / or the reflectance of the place which is performing the flame treatment of the thin film 2 for pattern formation is shown. In the example shown in FIG. 5, the incident light 122 can be irradiated to the place where the flame treatment is performed in order to irradiate the incident light 122 obliquely with respect to the surface of the pattern forming thin film 2. Therefore, by arranging the light receiving portion 108a for the transmitted light 124 and the light receiving portion 108b for the reflected light 126 at predetermined positions, the reflected light 126 and / or the transmitted light 124 by the pattern forming thin film can be measured. Therefore, in the example shown in FIG. 5, the measurement of the reflected light 126 and / or the transmitted light 124 at the place where the flame treatment is performed can be performed simultaneously with the flame treatment.

  According to the example shown in FIGS. 3 to 5 described above, for example, the reflected light 126 and / or the transmitted light 124 at a predetermined location of the pattern forming thin film 2 can be appropriately quantified. This also makes it possible to appropriately evaluate the degree of flame treatment at a predetermined location of the pattern forming thin film 2.

According to the mask blank obtained by subjecting the thin film for pattern formation to the main flame treatment, an ArF excimer laser is applied to the obtained transfer mask with an energy of 20 mJ / (cm ² · pulse) and a pulse frequency of 100 Hz. When continuous irradiation is performed for about 6600 seconds (110 minutes) at a density (integrated dose 12.2 kJ / cm ² ), the change in transmittance (change in transmittance normalized to the value before laser irradiation) is about 10%. be able to. Further, the increase in the line width (CD fluctuation amount) of the pattern made of the pattern forming thin film can be suppressed to 5 nm or less. Furthermore, when the pattern forming thin film is a halftone phase shift film, the amount of change in the phase shift amount caused in the exposure light transmitted through the halftone phase shift film can be within 3.0 degrees. .

Note that the integrated dose of 12.2 kJ / cm ² (energy density of about 25 mJ / cm ² ) corresponds to using the transfer mask approximately 45,750 times, and is approximately the frequency of use of the normal transfer mask. Equivalent to using for 3 months. Therefore, even with only this flame treatment, it is possible to further improve the light resistance of a pattern forming thin film such as a light semi-transmissive film with respect to exposure light having a wavelength of 200 nm or less, and to improve the life of a transfer mask. It can be said that it will be possible.

  As described above, the flame treatment is performed on the mask blank. However, the transfer mask life can be remarkably improved by performing the similar flame treatment on the transfer mask.

  The manufacturing method of the present invention is particularly suitable for manufacturing a mask blank for manufacturing a transfer mask used in an exposure apparatus that uses exposure light having a short wavelength of 200 nm or less as an exposure light source. For example, it is suitable for manufacturing the following mask blank.

(1) Phase shift mask blank in which the pattern forming thin film is a light semi-transmissive film made of a compound of a transition metal and silicon-containing material (transition metal silicide, particularly molybdenum silicide) The phase shift mask manufactured according to the present invention When the blank is used as a phase shift mask, even if the transfer mask is repeatedly used with short wavelength light such as ArF excimer laser as an exposure light source, the transmittance and phase difference of the phase shift film are changed. -Line width changes can be suppressed, performance is not degraded, and the life of the transfer mask can be significantly improved.

As such a phase shift mask blank, a halftone type having a halftone type phase shift film on a translucent substrate and having a shifter portion by patterning the halftone type phase shift film There is a mask blank for a phase shift mask.
The halftone phase shift film transmits light having an intensity that does not substantially contribute to exposure (for example, 1% to 20% with respect to the exposure wavelength), and has a predetermined phase difference (for example, 180 degrees). And a phase shift portion obtained by patterning the halftone phase shift film, and a light transmission portion that does not have the phase shift portion and that transmits light having an intensity that substantially contributes to exposure. The phase of the light transmitted through the light transmitting portion is substantially inverted with respect to the phase of the light transmitted through the light transmitting portion, so that the light passes through the vicinity of the boundary between the phase shift portion and the light transmitting portion. Light that wraps around each other due to diffraction phenomenon cancels each other out, and the light intensity at the boundary is almost zero, improving the contrast of the boundary, that is, the resolution.

The phase shift mask blank has a light shielding film or a light semi-transmissive film on a light transmissive substrate, and is a substrate digging type in which a shifter portion is formed by digging the light transmissive substrate by etching or the like. And a mask blank for a Levenson type phase shift mask and an enhancer type phase shift mask.
Further, as a phase shift mask blank, in order to prevent a pattern defect of the transferred substrate due to the light semi-transmissive film pattern formed in the transfer region based on the light transmitted through the light semi-transmissive film, the light semi-transparent substrate is formed on the light-transmissive substrate. The thing etc. which have a form which has a permeable film and the light shielding film on it are mentioned.

The light semi-transmissive film such as the halftone phase shift film is made of a compound of a transition metal and silicon (transition metal silicide), and the transition metal silicide and oxygen and / or nitrogen as main components. Materials to be used. As the transition metal, molybdenum, tantalum, tungsten, titanium, hafnium, nickel, vanadium, zirconium, niobium, palladium, ruthenium, rhodium, or the like is applicable.
In particular, when the phase shift film is formed of molybdenum silicide nitride (MoSiN) and flame treatment is performed, the MoSiN film has a desired phase difference and transmittance while suppressing a change in transmittance due to the flame treatment. The ratio of the Mo content divided by the total content of Mo and Si is preferably such that Mo is 9 at% or more and 14 at% or less (preferably 11 at% or more and 13 at% or less).

Further, in the case of having a light shielding film on the light semi-transmissive film, the material of the light semi-transmissive film contains a transition metal silicide. Therefore, the material of the light shielding film has an etching selectivity with respect to these films. (Having etching resistance), and chromium compounds in which elements such as oxygen, nitrogen, and carbon are added to chromium.
Further, in the case where the light shielding film is provided on the light semi-transmissive film, flame treatment may be performed on the main surface of the light semi-transmissive film before the light shielding film is formed.

(2) Binary mask blank in which the thin film for pattern formation is a light-shielding film made of a compound of a transition metal and silicon-containing material (transition metal silicide, particularly molybdenum silicide) The light-shielding film produced according to the present invention is a transition metal silicide When the binary mask blank of the system is used as a binary mask, even if the transfer mask is repeatedly used by using short wavelength light such as an ArF excimer laser as an exposure light source, the light shielding property of the light shielding film is reduced. The change in line width and the like can be suppressed, the performance is not deteriorated, and the life of the transfer mask can be remarkably improved.

  Such a binary mask blank has a light-shielding film on a light-transmitting substrate, and this light-shielding film is made of a material containing a transition metal silicide compound, and contains these transition metal silicide and oxygen and / or nitrogen. Materials that are the main constituent elements are listed. As the transition metal, molybdenum, tantalum, tungsten, titanium, hafnium, nickel, vanadium, zirconium, niobium, palladium, ruthenium, rhodium, or the like is applicable.

In particular, when the light shielding film is formed of a molybdenum silicide compound, the light shielding layer (MoSi, MoSiN, MoSiC, MoSiCN, etc.) and the surface antireflection layer (MoSiON, MoSiN, MoSiCN, MoSiCON, etc.) have a two-layer structure, Furthermore, when a back-surface antireflection layer (MoSiON, MoSiN, MoSiCN, MoSiCON, etc.) is added between the light shielding layer and the substrate, the Mo content in the molybdenum silicide compound of the light shielding layer is the sum of Mo and Si. The ratio divided by the content is preferably set so that Mo is 9 at% or more and 40 at% or less (preferably 15 at% or more and 40 at% or less, more preferably 20 at% or more and 40 at% or less) from the viewpoint of light shielding properties.
Moreover, it is good also as a composition gradient film | membrane from which the composition in the film thickness direction of a light shielding film differs continuously or in steps.

  As the light-shielding film (pattern forming thin film) having a two-layer structure, for example, from the light-transmitting substrate side, MoSiN (the ratio obtained by dividing the Mo content by the total content of Mo and Si is 9 at% or more and 40 at% or less. ) And a surface antireflection layer made of MoSiON (Mo content in the film is 10 at% or less). As a more specific example, a light-shielding layer having a thickness of 50 nm made of MoSiN (Mo: 14.7 at%, Si: 56.2 at%, N: 29.1 at%), and MoSiON (from the light transmitting substrate side) (Mo: 2.6 at%, Si: 57.1 at%, O: 15.9 at%, N: 24.4 at%) A two-layer structure of a surface antireflection layer with a film thickness of 10 nm and optical for ArF exposure light A light-shielding film (thin film for pattern formation) having a concentration of 3.0 is exemplified.

Further, in order to form a fine pattern by reducing the thickness of the resist film, an etching mask film may be provided on the light shielding film. This etching mask film is made of chromium having etching selectivity (etching resistance) with respect to the etching of the light-shielding film containing transition metal silicide, or a chromium compound in which elements such as oxygen, nitrogen, and carbon are added to chromium. Consists of.
In the case where the etching mask film is provided on the light shielding film, flame treatment may be performed on the main surface of the light shielding film before the etching mask film is formed.

The present invention also provides a method for producing a transfer mask having a step of patterning the thin film for pattern formation in the mask blank obtained by the present invention described above by etching. As the etching in this case, dry etching effective for forming a fine pattern is preferably used.
According to such a method for manufacturing a transfer mask, the light resistance to an exposure light source of a short wavelength such as an ArF excimer laser is improved, and deterioration of transfer characteristics due to exposure light irradiation can be suppressed even when the transfer mask is repeatedly used. A transfer mask having a significantly improved life of the mask can be obtained.

  By the flame treatment in the production method of the present invention, the transmittance and phase difference of the pattern forming thin film change. Since the transmittance of the pattern forming thin film tends to increase due to the flame treatment, it is necessary to design the transmittance of the pattern forming thin film to be lower than a desired value. Therefore, in the step of forming the pattern forming thin film, it is necessary to form a film having a film quality that allows for the change due to the flame treatment of the pattern forming thin film. The transmittance of the pattern forming thin film can be adjusted by, for example, the type of gas mixture and the mixing ratio used for film formation by sputtering film formation. Specifically, when the mixed gas is argon and nitrogen, the transmittance of the pattern forming thin film can be adjusted to be low by reducing the ratio of nitrogen. Further, the transmittance can be adjusted to be low in advance by increasing the content of the transition metal.

  In addition, you may perform a flame treatment again with respect to the mask for transfer produced using the mask blank of this invention. That is, the flame treatment may be performed again on the transfer mask manufactured using the mask blank subjected to the flame treatment described above. In addition, the obtained mask blank or transfer mask can be subjected to a heat treatment other than the flame treatment. It is also possible to measure the local optical characteristics of the thin film for pattern formation and perform the flame treatment again only on the part having a problem with the measured value of optical characteristics or the in-plane uniformity.

  In addition to the flame treatment of the present invention at the mask blank stage, the flame treatment of the present invention is also performed on the formed transfer pattern, thereby making it possible to further reduce line width change (line width thickening). Become.

Hereinafter, the present invention will be described more specifically with reference to examples.
Example 1
FIG. 1 is a schematic cross-sectional view of a phase shift mask blank 10 produced according to examples and comparative examples.
A synthetic quartz glass substrate having a size of 6 inches square and a thickness of 0.25 inches (6.35 mm) is used as the translucent substrate 1, and a halftone phase made of molybdenum and silicon nitrided on the translucent substrate 1. A shift film (pattern forming thin film) 2 was formed.
Specifically, using a mixed target of molybdenum (Mo) and silicon (Si) (Mo: Si = 10 at%: 90 at%), mixing argon (Ar), nitrogen (N ₂ ), and helium (He) In a gas atmosphere (gas flow ratio Ar: N ₂ : He = 8: 72: 100), a gas pressure of 0.3 Pa, a DC power source power of 3.0 kW, reactive sputtering (DC sputtering), molybdenum, silicon, and A MoSiN film made of nitrogen was formed to a thickness of 69 nm. Next, the substrate on which the MoSiN film was formed was subjected to a heat treatment as an annealing treatment. Specifically, using a heating furnace, heat treatment was performed in the atmosphere at a heating temperature of 280 ° C. and a heating time of 2 hours. This MoSiN film had an transmittance of 6.1% and a phase difference of 179 degrees in an ArF excimer laser.

Next, flame treatment was performed on the substrate on which the MoSiN film was formed under the following conditions.
・ Flame temperature: 1500 ℃
・ Distance between flame irradiation device and mask blank: 10mm
・ Flame diameter: 15mm
-Flame scanning: Stopping and moving were repeated stepwise, and scanning was performed so as to irradiate the flame for 10 minutes at one location.
・ Type of flammable gas: Butane gas

The MoSiN film after the flame treatment had an transmittance of 11.8% and a phase difference of 175 degrees in an ArF excimer laser. Therefore, the amount of change before and after the flame treatment is a transmittance of + 5.7% and a phase difference of −4 degrees. It should be noted that the film design may be performed so that the desired optical characteristics can be obtained in consideration of the amount of change.
As described above, the mask blank 10 of this example was manufactured.

  Next, a halftone phase shift mask was produced using the above phase shift mask blank. FIG. 2 is a schematic cross-sectional view showing a process of manufacturing a phase shift mask using a phase shift mask blank. First, a chemically amplified positive resist film for electron beam drawing (PRL009 manufactured by Fuji Film Electronics Materials Co., Ltd.) was formed on the mask blank 10 as the resist film 3 (see FIG. 1A). The resist film 3 was formed by spin coating using a spinner (rotary coating apparatus).

Next, a desired pattern was drawn on the resist film 3 formed on the mask blank 10 using an electron beam drawing apparatus, and then developed with a predetermined developer to form a resist pattern 3a (see FIG. (See (b) and (c)).
Next, using the resist pattern 3a as a mask, the halftone phase shift film 2 (MoSiN film) was etched to form the phase shift film pattern 2a (see FIG. 4D). A mixed gas of SF ₆ and He was used as the dry etching gas.
Next, the remaining resist pattern was peeled off to obtain the phase shift mask 20 (see FIG. 5E). The transmittance and phase difference of the phase shift film were hardly changed from those at the time of manufacturing the mask blank.

The phase shift mask obtained in Example 1 was continuously irradiated with an ArF excimer laser at an energy density of 20 mJ / (cm ² · pulse) and a pulse frequency of 100 Hz for about 6600 seconds (110 minutes). The transmittance of the ArF excimer laser after irradiation for 110 minutes was 10.7%, and the change in normalized transmittance was about -9%.
Further, when the cross section of the phase shift pattern was observed in detail using a TEM (transmission electron microscope), a thick deteriorated layer, which has been generated conventionally, was not confirmed, and the line width was increased (CD fluctuation amount). Was also suppressed to less than 5 nm. Therefore, it can be seen that the phase shift mask blank and the phase shift mask of Example 1 have extremely high light resistance against cumulative irradiation with an exposure light source having a short wavelength of 200 nm or less.

(Example 2)
In Example 2, a phase shift mask was used in the same manner as in Example 1 except that optical measurement (specifically, measurement of transmittance) was performed simultaneously with the flame treatment on the substrate on which the MoSiN film was formed. Manufactured. The transmittance during the flame treatment was measured using an apparatus as shown in FIG.

As in Example 1, the ArF excimer laser was continuously irradiated for about 6600 seconds (110 minutes) at an energy density of 20 mJ / (cm ² · pulse) and a pulse frequency of 100 Hz to the phase shift mask obtained in Example 2. did. In the phase shift mask of Example 2, the change in normalized transmittance was about -9% even after 110 minutes of irradiation with the ArF excimer laser.
Further, when the cross section of the phase shift pattern was observed in detail using a TEM (transmission electron microscope), a thick deteriorated layer, which has been generated conventionally, was not confirmed, and the line width was increased (CD fluctuation amount). Was also suppressed to less than 5 nm. Therefore, it can be seen that the phase shift mask blank and the phase shift mask of Example 2 have extremely high light resistance against cumulative irradiation by an exposure light source having a short wavelength of 200 nm or less.

(Comparative Example 1)
In Comparative Example 1, a phase shift mask was manufactured in the same manner as in Example 1 except that only the heat treatment with an electric furnace was performed without performing the flame treatment.

The conditions for the heat treatment by the electric furnace for Comparative Example 1 are as follows.
・ Heating temperature: 280 ℃
・ Heating time: 2 hours ・ Heating atmosphere: in air

As in Example 1, the ArF excimer laser was continuously irradiated for about 6600 seconds (110 minutes) at an energy density of 20 mJ / (cm ² · pulse) and a pulse frequency of 100 Hz to the phase shift mask obtained in Comparative Example 1. did. In the phase shift mask of Comparative Example 1, the change in normalized transmittance was about 15% after irradiation of the ArF excimer laser for about 6600 seconds (110 minutes).
Further, when the cross section of the phase shift pattern was observed in detail using a TEM (transmission electron microscope), a thick deteriorated layer as particularly generated was confirmed. Also, the line width (CD variation) was larger than 10 nm. Therefore, it can be seen that the phase shift mask blank and the phase shift mask of Comparative Example 1 do not have high light resistance against cumulative irradiation with an exposure light source having a short wavelength of 200 nm or less.

1 Translucent substrate 2 Halftone phase shift film (thin film for pattern formation)
3 resist film 10 mask blank (phase shift mask blank)
20 Flame irradiation device 22 Flame 100 Flame treatment device 102 Stage 104 UV light source portion 106 UV irradiation portion 108 Light receiving portion 108a Light receiving portion (for transmitted light)
108b Light-receiving part (for reflected light)
110 Spectrometer 112 Stage Controller 114 Control Unit 122 Incident Light 124 Transmitted Light 126 Reflected Light

Claims (8)

A method for manufacturing a mask blank provided with a thin film for pattern formation on a translucent substrate,
Forming a thin film for pattern formation made of a material containing transition metal and silicon on the translucent substrate;
And a step of flame-treating the pattern forming thin film,
The method of manufacturing a mask blank, wherein the flame treatment step includes irradiating a flame while measuring optical characteristics of the pattern forming thin film .   The mask blank manufacturing method according to claim 1, wherein the flame treatment includes scanning the entire surface of the pattern forming thin film while locally irradiating a flame. Wherein the optical characteristic is at least one selected from the transmittance and reflectance, method for producing a mask blank according to claim 1 or 2, wherein. The pattern-forming thin film is a light semi-transmissive film made of a material mainly composed of a compound containing transition metal and silicon and one or more elements selected from oxygen and nitrogen, or a material containing at least a transition metal and silicon The manufacturing method of the mask blank of any one of Claims 1-3 which is the light shielding film for binary masks which consists of these. The mask blank manufactured by the manufacturing method of any one of Claims 1-4 . A transfer mask in which a transfer pattern is formed on the pattern forming thin film of the mask blank according to claim 5 . A method for producing a transfer mask provided with a transfer pattern on a translucent substrate,
Preparing a mask blank having a thin film for pattern formation made of a material containing transition metal and silicon on a light-transmitting substrate;
Forming a transfer pattern on the pattern forming thin film of the mask blank;
And a step of flame-treating the pattern forming thin film on which the transfer pattern is formed,
The method for manufacturing a transfer mask , wherein the step of performing the flame treatment includes irradiating a flame while measuring optical characteristics of the pattern forming thin film . A transfer mask manufactured by the manufacturing method according to claim 7 .

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