JP5906143B2 - Mask blank, transfer mask, transfer mask manufacturing method, and semiconductor device manufacturing method - Google Patents

Description

  The present invention relates to a mask blank, a transfer mask, a transfer mask manufacturing method, and a semiconductor device manufacturing method.

  Generally, in a semiconductor device manufacturing process, a fine pattern is formed using a photolithography method. For the formation of this fine pattern, usually a number of substrates called transfer masks are used. This transfer mask is generally a transparent glass substrate provided with a fine pattern made of a metal thin film or the like. A photolithography method is also used in the production of the transfer mask.

  In order to miniaturize the 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, the exposure light source used in the manufacture of semiconductor devices has been shortened from a 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 phase shift mask is provided with a light semi-transmissive film pattern on a light-transmitting substrate. This light semi-transmissive film (halftone phase shift film) transmits light at an intensity that does not substantially contribute to exposure, and the light that has passed through the light semi-transmissive film through the air for the same distance. Has a function of causing a predetermined phase difference, thereby producing a so-called phase shift effect.

  In general, the outer peripheral area of the transfer mask on which the transfer pattern is formed is affected by the exposure light transmitted through the outer peripheral area when the exposure film is exposed and transferred to the resist film on the semiconductor wafer. Therefore, it is required to secure an optical density (OD) equal to or higher than a predetermined value. Usually, it is desirable that the OD is 3 or more in the outer peripheral region of the transfer mask, and at least about 2.8 is required. However, the light semi-transmissive film of the halftone phase shift mask has a function of transmitting the exposure light with a predetermined transmittance, and this light semi-transmissive film alone is required in the outer peripheral region of the transfer mask. It is difficult to ensure the optical density. For this reason, as in the phase shift mask blank disclosed in Patent Document 1, a light shielding film (light shielding film) is laminated on a semitransparent film having a predetermined phase shift amount and transmittance with respect to exposure light. A predetermined optical density is secured by a laminated structure of a translucent film and a light shielding film.

  On the other hand, there is a photomask blank as disclosed in Patent Document 2. The translucent laminated film of this photomask blank has a phase advance film having a characteristic that the phase of the exposure light transmitted through the film is more advanced than the phase of the exposure light that has passed through the air by the same distance, and conversely A phase retardation film having a characteristic that the phase of exposure light transmitted therethrough is delayed is laminated. By adopting such a configuration, it is possible to prevent a phase difference between the exposure light transmitted through the translucent laminated film and the exposure light that has passed through the air by the same distance. A semitransparent laminated film having such characteristics alone is difficult to ensure the optical density required for the outer peripheral region of the transfer mask. For this reason, also in the photomask blank disclosed in Patent Document 2, a light shielding film is laminated on the semitransparent laminated film, and a predetermined optical density is ensured by a laminated structure of the semitransparent laminated film and the light shielding film. I have to.

JP 2007-033469 A JP 2006-215297 A

  A transfer mask of a type that forms a transfer pattern with a thin film (light semi-transmissive film) that transmits exposure light at a predetermined transmittance as disclosed in Patent Document 1 and Patent Document 2 is a light semi-transmissive film. It is manufactured using a mask blank in which a light-shielding film is laminated on top. In the transfer mask produced from this mask blank, only the pattern of the light translucent film exists in the region where the transfer pattern on the substrate is formed, except for a specific region where a light shielding patch or the like needs to be formed. To do. On the other hand, in the outer peripheral region (blind area) where a predetermined optical density is required, there is a layer (light-shielding band) in which the light semi-transmissive film and the light-shielding film are laminated. Since it is necessary to prepare a transfer mask having such a configuration, in the case of a structure in which a light semi-transmissive film and a light-shielding film are stacked without interposing another film, the light semi-transmissive film and the light-shielding film are It is necessary to form with materials having different etching characteristics.

  The procedure for producing the transfer mask from the mask blank as described above is as follows. First, a first resist pattern having a pattern to be formed on the light semi-transmissive film is provided on the light shielding film. Next, the light shielding film is etched using the first resist pattern as a mask to form a pattern. Next, the first resist pattern is removed. Next, using the light shielding film pattern as a mask, the light semi-transmissive film is etched to form a light semi-transmissive film pattern. Next, a second resist pattern having a pattern to be formed on the light shielding film is provided on the light shielding film. Next, the light shielding film is etched using the second resist pattern as a mask to form a light shielding film pattern (light shielding band). Finally, the second resist pattern is removed, and a transfer mask is completed through a predetermined cleaning process.

  The pattern to be formed on the light semi-transmissive film is a very fine pattern because it is exposed and transferred to a resist film on a semiconductor wafer. However, since the light shielding film is laminated on the light semi-transmissive film in the mask blank, a pattern to be formed on the light semi-transmissive film must be formed once on the light shielding film. As described above, the light semi-transmissive film often has a function other than transmitting exposure light at a predetermined transmittance. And in order to give such a characteristic to a light semi-transmissive film, a material containing silicon or a material containing silicon and a transition metal is often applied. When a fine pattern is formed on a light semi-transmissive film made of these materials, it is desirable to pattern by dry etching using a fluorine-based gas.

  Assuming that the light semi-transmissive film is patterned by dry etching with a fluorine-based gas, the light-shielding film is made of a material that is resistant to dry etching with a fluorine-based gas in order to realize the transfer mask manufacturing process. There must be. In addition, it is necessary that a fine pattern to be formed on the light semi-transmissive film can be formed on the light shielding film with an etching gas other than the fluorine-based gas. A material for the light shielding film that satisfies these conditions simultaneously includes a material containing chromium, which has been conventionally used. An etching gas used for forming a fine pattern on the light-shielding film made of a material containing chromium is a mixed gas of a chlorine-based gas and an oxygen gas.

  However, a resist film formed of a commonly used organic material has significantly lower resistance to plasma of oxygen gas than that of other gases. For this reason, when the light-shielding film made of a chromium-based material is dry-etched with a mixed gas of chlorine-based gas and oxygen gas, the consumption of the resist film (the reduction amount of the resist film generated during the etching) increases. In order to form a fine pattern on the light shielding film with high accuracy by dry etching, the resist film needs to remain with a predetermined thickness or more upon completion of patterning of the light shielding film. However, if the thickness of the resist film that forms the pattern first is increased, the cross-sectional aspect ratio of the resist pattern (the ratio of the film thickness to the pattern line width) becomes too large, so the phenomenon that the resist pattern collapses easily occurs. Become. As a method for solving this problem, it is conceivable to reduce the thickness of the light shielding film or to increase the etching rate of the light shielding film.

  A thin film made of a chromium-containing material tends to increase the etching rate when dry etching is performed with a mixed gas of a chlorine-based gas and an oxygen gas as the oxygen content in the film increases. In general, a thin film containing a metal tends to decrease in optical density as the oxygen content in the film increases. In a light-shielding film made of a material containing chromium, it is necessary to reduce the oxygen content in the film when attempting to secure an optical density higher than a predetermined value with a thin film thickness. Therefore, in a mixed gas of chlorine-based gas and oxygen gas, The etching rate becomes slow, and it becomes difficult to reduce the thickness of the resist film. Further, in a light-shielding film made of a material containing chromium, if an attempt is made to increase the etching rate with a mixed gas of chlorine-based gas and oxygen gas, it is necessary to increase the oxygen content in the film. The film thickness of the light-shielding film necessary for securing it becomes thick, and it becomes difficult to reduce the film thickness of the resist film.

  As a means for solving such a problem, it is considered to apply a mask blank in which an etching mask film (hard mask film) made of a material containing silicon is laminated on a light shielding film made of a material containing chromium. ing. However, in the case of this mask blank, it is necessary to apply a process in which each layer is alternately etched with different etching gases, so that there is a problem that the manufacturing process of the transfer mask becomes complicated.

  In recent years, a double patterning technique has begun to be applied as a technique for exposing and transferring a finer pattern. The double patterning technology is a technology that divides a fine transfer pattern into two relatively sparse transfer patterns so that a fine pattern that could not be realized by lithography using conventional ArF exposure light can be exposed and transferred. Technology. In lithography using this double patterning technology, the same resist film on a semiconductor wafer is exposed and transferred in sequence using two transfer masks on which patterns divided by the double patterning technology are formed. There is a double exposure technology that performs this. When this double exposure technique is used, the amount of exposure light that passes through the outer peripheral region of the transfer mask is irradiated onto the resist on the semiconductor wafer is twice that of the prior art. Conventionally, in the case of a transfer mask (binary mask) using a light-shielding film having a higher optical density than the light semi-transmissive film, the influence of the exposure light transmitted through the peripheral area of the transfer mask on the resist film on the semiconductor wafer Did not need to be considered. However, when this double exposure technique is applied, it is necessary to consider forming a light-shielding band in the outer peripheral region even for a transfer mask that forms a transfer pattern on a light-shielding film having a relatively high optical density. For this reason, even in the case of the binary mask, the same problem as in the case of the halftone phase shift mask may occur.

  Therefore, the present invention has been made to solve the conventional problems, and the object of the present invention is to stack a second film such as a light shielding film on a first film such as a light semi-transmissive film. By providing a mask blank capable of forming a fine pattern even if dry etching is performed on the second film with a mixed gas of chlorine-based gas and oxygen gas using the resist pattern as a mask. is there. Moreover, it is providing the transfer mask manufactured using this mask blank, and its manufacturing method. Furthermore, it is providing the manufacturing method of the semiconductor device using this transfer mask.

In order to achieve the above object, the present invention has the following configuration.
(Configuration 1)
A mask blank having a structure in which a first film and a second film are sequentially laminated on a substrate from the substrate side, which is used for producing a transfer mask;
The first film is made of a material that can be dry-etched with a fluorine-based gas,
The second film has a laminated structure of a lower layer and an upper layer,
The lower layer is made of a material containing molybdenum or tungsten and having a silicon content of 0 at% or more and less than 10 at%,
The upper layer is made of a material containing chromium and oxygen, a chromium content of less than 50 at%, and an oxygen content of 25 at% or more.

(Configuration 2)
2. The mask blank according to Configuration 1, wherein the lower layer is made of a material containing molybdenum or tungsten and not containing silicon.
(Configuration 3)
3. The mask blank according to Configuration 1 or 2, wherein the lower layer is made of a material further containing nitrogen.

(Configuration 4)
4. The mask blank according to any one of configurations 1 to 3, wherein the second film is made of a material that can be dry-etched by a mixed gas of a chlorine-based gas and an oxygen gas.
(Configuration 5)
The first film is made of a material containing silicon, or a material containing silicon and a transition metal, wherein the silicon content is higher than the content of the transition metal. The mask blank according to any one of 1 to 4.

(Configuration 6)
6. The mask blank according to any one of configurations 1 to 5, wherein an oxide layer is formed on a surface layer on the second film side of the first film.
(Configuration 7)
7. The mask blank according to any one of configurations 1 to 6, wherein a resist film is formed with a thickness of 100 nm or less in contact with the surface of the upper layer.

(Configuration 8)
8. The mask blank according to any one of configurations 1 to 7, wherein the laminated structure of the first film and the second film has an optical density with respect to ArF exposure light of 2.8 or more.
(Configuration 9)
9. The mask blank according to any one of configurations 1 to 8, wherein the first film is a light semi-transmissive film having a transmittance with respect to ArF exposure light of 1% or more.

(Configuration 10)
A transfer mask in which a first film having a first pattern and a second film having a second pattern are sequentially stacked on a substrate from the substrate side,
The first film is made of a material that can be dry-etched with a fluorine-based gas,
The second film has a laminated structure of a lower layer and an upper layer,
The lower layer is made of a material containing molybdenum or tungsten and having a silicon content of 0 at% or more and less than 10 at%,
The transfer mask according to claim 1, wherein the upper layer is made of a material containing chromium and oxygen, a chromium content of less than 50 at%, and an oxygen content of 25 at% or more.

(Configuration 11)
The transfer mask according to Configuration 10, wherein the lower layer is made of a material containing molybdenum or tungsten and not containing silicon.
(Configuration 12)
The transfer mask according to Configuration 10 or 11, wherein the lower layer is made of a material further containing nitrogen.

(Configuration 13)
13. The transfer mask according to any one of configurations 10 to 12, wherein the second film is made of a material that can be dry-etched by a mixed gas of a chlorine-based gas and an oxygen gas.
(Configuration 14)
The first film is made of a material containing silicon, or a material containing silicon and a transition metal, wherein the silicon content is higher than the content of the transition metal. The transfer mask according to any one of 10 to 13.

(Configuration 15)
15. The transfer mask according to any one of Structures 10 to 14, wherein the first film has an oxide layer formed on a surface layer on the second film side.
(Configuration 16)
16. The transfer mask according to any one of configurations 10 to 15, wherein the laminated structure of the first film and the second film has an optical density with respect to ArF exposure light of 2.8 or more.

(Configuration 17)
17. The transfer mask according to any one of configurations 10 to 16, wherein the first film is a light semi-transmissive film having a transmittance with respect to ArF exposure light of 1% or more.

(Configuration 18)
A method for manufacturing a transfer mask using the mask blank according to any one of configurations 1 to 9,
A resist film having a first pattern is formed in contact with the surface of the second film, and the first pattern is formed on the second film by dry etching using a mixed gas of chlorine-based gas and oxygen gas. And a process of
Step of forming the first pattern on the first film by removing the resist film having the first pattern and then using the second film having the first pattern as a mask by dry etching using a fluorine-based gas When,
A resist film having a second pattern is formed in contact with the surface of the second film, and a second pattern is formed on the second film by dry etching using a mixed gas of chlorine-based gas and oxygen gas. And a process for producing a transfer mask.

(Configuration 19)
The method for manufacturing a transfer mask according to Configuration 18, wherein the resist film having the first pattern has a thickness of 100 nm or less.
(Configuration 20)
A method for manufacturing a semiconductor device, comprising: a step of exposing and transferring a first pattern onto a resist film on a semiconductor substrate using the transfer mask according to any one of Structures 10 to 17.
(Configuration 21)
A method for manufacturing a semiconductor device, comprising: a step of exposing and transferring a first pattern onto a resist film on a semiconductor substrate using the transfer mask manufactured by the method for manufacturing a transfer mask according to Configuration 18 or 19. Method.

  The mask blank of the present invention has a structure in which a first film and a second film are sequentially laminated from the substrate side, and the first film is made of a material that can be dry-etched with a fluorine-based gas, The film contains molybdenum or tungsten, and a lower layer made of a material having a silicon content of 0 at% or more and less than 10 at%, chromium and oxygen, the chromium content is less than 50 at%, and contains oxygen It has a laminated structure of an upper layer made of a material whose amount is 25 at% or more. By using a mask blank having such a structure, even when dry etching using a mixed gas of chlorine-based gas and oxygen gas is applied using a resist film with a film thickness of 100 nm or less as a mask, the second film is used as the second film. The first pattern, which is a fine pattern to be formed on the first film, can be formed with high accuracy. Thus, the first pattern, which is a fine pattern, can be formed with high accuracy on the first film using the second film as a mask. Furthermore, an optical density equal to or higher than a predetermined value required for the outer peripheral region of the transfer mask can be ensured by the laminated structure of the second film and the first film.

  Further, by using the mask blank having such a structure, the first pattern, which is a fine pattern, is formed with high accuracy in the first film, and the laminated structure of the first film and the second film. Thus, a transfer mask in which the optical density in the outer peripheral region is a predetermined value or more can be manufactured. Furthermore, a pattern can be formed on a semiconductor device with high accuracy by exposing and transferring the pattern onto a resist film on the semiconductor device using the transfer mask having such a structure.

It is sectional drawing which shows the structure of the mask blank in embodiment of this invention. It is sectional drawing which shows the manufacturing process of the transfer mask in embodiment of this invention.

Embodiments of the present invention will be described below.
The inventors of the present invention have earnestly studied a material having a high optical density as a material applied to the light-shielding film (second film) and having a high etching rate in dry etching using a mixed gas of chlorine-based gas and oxygen gas. I did research. It is difficult to avoid a decrease in optical density of a material containing oxygen. Therefore, the etching rate of dry etching using a mixed gas of chlorine-based gas and oxygen gas is the same or faster than that of materials containing oxygen and chromium. We searched for materials to become. As a result, it was found that molybdenum and tungsten satisfy the above conditions.

  Table 1 shows the results of verification of a thin film of a material containing chromium (Cr) and a thin film of a material containing molybdenum (Mo). In addition, the element content in each film | membrane in Table 1 is an analysis value by Auger electron spectroscopy (AES). Each thin film used for verification is formed on a synthetic quartz substrate by a sputtering method (DC sputtering method).

In this verification, no. 1-No. For the thin film of each material of No. 9, the etching rate when dry etching with a mixed gas of chlorine gas and oxygen gas (gas flow ratio Cl ₂ : O ₂ = 4: 1) was performed under the same conditions was calculated. Conventionally, a film having a relatively high etching rate is No. The ratio based on the etching rate of the film No. 1 (CrOCN film) 1-No. Calculation was performed for each of the nine materials.
No. 1-No. The optical density was measured for each of the nine materials, and the film thickness necessary to form a thin film having an optical density (OD) of 1.9 was calculated. And No. No. 1 film (CrOCN film), the ratio based on the film thickness. 1-No. Calculation was performed for each of the nine materials.
Furthermore, by dividing the film thickness ratio required for OD1.9 calculated above by the etching rate ratio calculated above, No. 1-No. No. 9 of each material. The ratio of etching time to 1 film (CrOCN film) was calculated.
In addition, No. No. 7 film (MoSiN film) is a film having optical characteristics applicable as a halftone phase shift film.

  As shown in Table 1, a thin film made of a material containing chromium increases the etching rate with respect to a mixed gas of chlorine and oxygen, and reduces the film thickness to ensure a predetermined optical density. It is not easy to satisfy the two requirements at the same time. In contrast, no. 5 and no. Even if the thin film made of the material containing molybdenum 6 does not contain oxygen, the etching rate for the mixed gas of chlorine and oxygen is equal to or higher than that of the thin film made of the material containing chromium. In addition, no. 5 and no. Since the thin film made of the material containing molybdenum 6 does not need to contain oxygen for improving the etching rate, the optical density is high and the film thickness for securing a predetermined optical density can be reduced. . In addition, No. As is apparent from the results for the thin film No. 7, it has been confirmed that etching with a mixed gas of chlorine and oxygen becomes difficult if a large amount of silicon is contained in addition to molybdenum.

  No. 8 and no. As for the thin film made of a material containing tungsten 9, the etching rate with respect to the mixed gas of chlorine and oxygen is slightly slower or faster than the thin film made of a material containing chromium even if oxygen is not contained. Has been obtained. In addition, no. 8 and no. The thin film made of the material containing tungsten 9 does not need to contain oxygen in order to improve the etching rate, so that the optical density is high, and the film thickness for securing a predetermined optical density can be reduced. .

On the other hand, in this verification, no. 1-No. For the thin film of each material No. 9, the etching rate when dry etching with a fluorine-based gas (mixed gas of SF ₆ and He) is performed under the same conditions is calculated. Conventionally, a film having a relatively high etching rate with respect to this etching gas is a film No. The ratio based on the etching rate of the film No. 7 (MoSiN film) 1-No. Table 1 also shows the results calculated for the thin films of the nine materials. As is clear from this result, the thin film made of the material containing molybdenum and the thin film made of the material containing tungsten have lower resistance to fluorine-based gas than the material containing chromium (the thin film No. 5 has It has been confirmed that the etching rate ratio to the fluorine-based gas is almost zero, but the surface of the thin film is altered.

  The thin film considered in these verifications is used for the light shielding film (second film). This light-shielding film needs to function as an etching mask when a fine pattern (first pattern) is formed by dry etching with a fluorine-based gas on the first film directly therebelow. For this reason, at least the surface of the second film opposite to the first film and the vicinity thereof are required to have etching resistance against dry etching of a fluorine-based gas.

  Here, as a method of forming a fine pattern (first pattern) on the first film in the mask blank in which the first film and the second film are stacked on the substrate, the surface of the second film is in contact with the mask blank. A method of forming a fine pattern by etching the first film while leaving the resist film after patterning by etching the second film using the formed resist film having a fine pattern as a mask is unthinkable. Absent. However, in order to apply such a method, the resist film needs to remain with a film thickness of a predetermined thickness or more until the pattern is completely formed on the first film, and the film thickness of the resist film must be increased. I will have to. In addition, if a resist film made of an organic material is present when the first film is dry-etched, defects due to organic substances increase, which is not preferable. Further, if the resist film disappears in the course of dry etching for forming a pattern on the first film, the plasma state of the etching gas changes before and after that, which adversely affects the etching of the first film.

  As a result of intensive studies, these materials have a two-layer structure of the upper layer and the lower layer, and the lower layer is a material having a high etching density and high optical density in dry etching using a mixed gas of chlorine-based gas and oxygen gas. By forming the upper layer, which is formed of a material containing molybdenum or tungsten, and is exposed to the etching gas of the fluorine-based gas when the first film is etched, by using a material containing chromium having high etching resistance to the fluorine-based gas. The idea of being able to solve the above problems has been reached. In the case of this configuration, since a high optical density can be secured with a thin film thickness in the lower layer of the second film, the material containing chromium forming the upper layer can relax restrictions on the optical density. From this, the upper layer was able to increase the etching rate by the mixed gas of chlorine-based gas and oxygen gas by setting the oxygen content to 25 at% or more while setting the chromium content to less than 50 at%.

  Furthermore, the lower layer made of a material containing molybdenum or tungsten needs to increase the etching rate of dry etching using a chlorine-based gas and an oxygen gas. As a result of investigating the influence of silicon that causes a significant decrease in the etching rate, it was concluded that if the silicon content in the second film is less than 10 at%, the influence on the etching rate is small. The present invention has been completed. As described above, the present invention is characterized in that the characteristics of the material forming the upper layer of the second film and the material forming the lower layer are greatly different, and the order of stacking the upper layer and the lower layer is important. If this stacking order is reversed, the present invention does not hold.

  As described above, the present invention is used for manufacturing a transfer mask, and is a mask blank having a structure in which a first film and a second film are sequentially stacked on a substrate from the substrate side. The first film is made of a material that can be dry-etched with a fluorine-based gas, the second film has a laminated structure of a lower layer and an upper layer, and the lower layer contains molybdenum or tungsten, A material having a silicon content of 0 at% or more and less than 10 at%, wherein the upper layer contains chromium and oxygen, the chromium content is less than 50 at%, and the oxygen content is 25 at% or more. It is related with the mask blank characterized by comprising.

  In the mask blank of the present invention, the lower layer of the second film is preferably formed of a material containing molybdenum or tungsten and not containing silicon. As described above, when silicon is contained in the second film, the etching rate of dry etching using a mixed gas of chlorine-based gas and oxygen gas is decreased. However, depending on the etching conditions, the etching rate of the lower layer in dry etching with a mixed gas of chlorine-based gas and oxygen gas becomes too fast compared to the etching rate of the upper layer, making it difficult to control the pattern sidewall shape. In the method, silicon may be contained in the lower layer in a range of less than 10 at%.

The material containing molybdenum or tungsten for forming the lower layer of the second film includes a material containing both molybdenum and tungsten. In order to adjust the etching rate, one or more of chromium, niobium, and vanadium may be added to the material forming the lower layer of the second film. In this case, it is necessary to reduce the content at least in the lower layer of molybdenum or tungsten, preferably 45 at% or less, more preferably 30 at% or less. Further, in order to adjust the film stress and the crystallinity in the lower layer of the second film, the material forming the lower layer may contain one or more of nitrogen, carbon, oxygen, and boron. In particular, by containing nitrogen in the material forming the lower layer, there is an effect of suppressing excessive oxidation.
In addition, about the case where oxygen is contained in the material which forms a lower layer, it is preferable to make content 30 at% or less from a viewpoint of the fall of optical density, and a chemical-resistant fall, and it is 20 at% or less. And more preferred.

  The lower layer of the second film preferably has a thickness of 5 nm or more. If the thickness of the lower layer is less than 5 nm, the ratio of the lower layer thickness to the total thickness of the second film is too low, and the effect of providing the lower layer is hardly obtained. The thickness of the lower layer of the second film is preferably 35 nm or less. When the film thickness of the lower layer is larger than 35 nm, it is possible to secure a predetermined optical density required for the second film only in the lower layer. However, since the upper layer is necessary to protect the lower layer from dry etching with a fluorine-based gas, the second film has an optical density higher than necessary and the film thickness is larger than necessary because the upper layer is provided. Therefore, it is not preferable.

  The upper layer of the second film is formed of a material containing chromium and oxygen. Examples of such a material include CrO, CrON, CrOCN, CrBON, and CrBOCN. In addition, tin may be contained in the above material. Inclusion of tin has the effect of further improving the etching rate. In consideration of further increasing the etching rate with respect to the mixed gas of chlorine-based gas and oxygen gas, the chromium content in the upper layer is preferably 45 at% or less, and more preferably 40 at% or less. On the other hand, the upper layer needs to have high resistance to the fluorine-based gas. Considering this point, the chromium content in the upper layer is preferably 30 at% or more, and more preferably 35 at% or more. In consideration of further increasing the etching rate with respect to the mixed gas of chlorine-based gas and oxygen gas, the oxygen content in the upper layer is preferably 35 at% or more, more preferably 40 at% or more.

  It is desirable that the upper layer of the second film also has a function of reducing surface reflection when exposure light strikes the second film. From the viewpoint of reducing surface reflection, the upper layer of the second film preferably has an oxygen content of 30 at% or more, and more preferably 35 at% or more. Furthermore, the upper layer preferably contains 10 at% or more of nitrogen, more preferably 15 at% or more.

  The upper layer of the second film preferably has a thickness of 3 nm or more. This is because if the thickness of the upper layer is less than 3 nm, the amount of change in the surface reflectance that occurs when the first film is finely etched while being dry-etched with a fluorine-based gas is increased. The thickness of the upper layer of the second film is preferably 30 nm or less. If the thickness of the upper layer is larger than 30 nm, the ratio of the thickness of the lower layer to the total thickness of the second film is relatively lowered. As a result, the etching rate for dry etching with chlorine-based gas and oxygen gas in the entire second film is relatively lowered, which is not preferable.

  In the mask blank of the present invention, the lower layer of the second film is preferably made of a material that can be dry-etched with a mixed gas of chlorine-based gas and oxygen gas. As materials suitable for the lower layer, all can be obtained by a sufficiently high etching rate by dry etching using a mixed gas of chlorine gas and oxygen gas.

  In the mask blank of the present invention, the first film is formed of a material that can be dry-etched with an etching gas containing fluorine. The first film is preferably a film having a function of transmitting exposure light at a predetermined transmittance, such as a halftone phase shift film or a translucent laminated film. This is because when the first film is a transfer mask having these functions, it is necessary to form a light-shielding band in the outer peripheral region, and the second film having the functions of the present invention is required. When the first film is a light semi-transmissive film such as a halftone phase shift film or a semi-transparent laminated film, the transmittance for exposure light is preferably 1% or more. Further, it is more preferable that the transmittance with respect to the exposure light is adjusted to be in the range of 1 to 20%. Further, the first film may be a light shielding film having an optical density equal to or higher than a predetermined value. In particular, in the case of a transfer mask to which the double exposure technique is applied, a light-shielding band may be formed in the outer peripheral region, so that the second film having the function of the present invention is required. When the first film is a light shielding film for a binary mask and an ArF excimer laser is applied to the exposure light, the optical density (OD) of the first film is 2 at the wavelength (about 193 nm). It is necessary to adjust so that it may become 3 or more, it is preferable that it is 2.5 or more, and it is more preferable that it is 2.8 or more.

  In the mask blank of the present invention, the first film is a material containing silicon or a material containing silicon and a transition metal, and silicon (Si) is more than the content [at%] of the transition metal (M). It is preferable that it consists of a material with much content [at%]. Transition metals in this case include molybdenum (Mo), tantalum (Ta), tungsten (W), titanium (Ti), chromium (Cr), hafnium (Hf), nickel (Ni), vanadium (V), zirconium ( Zr), ruthenium (Ru), rhodium (Rh), niobium (Nb), palladium (Pd), etc., any one or more metals or alloys of these metals. In addition to these metals, the material of the first film may include elements such as nitrogen (N), oxygen (O), carbon (C), hydrogen (H), and boron (B). . In addition, the material of the first film may include an inert gas such as helium (He), argon (Ar), krypton (Kr), or xenon (Xe).

  These materials have a high etching rate with respect to the fluorine-based gas, and easily obtain various characteristics required for the light semi-transmissive film. In particular, these materials form halftone phase shift films that require the phase of exposure light passing through the first film to be strictly controlled, and semitransparent laminated films in which a phase retardation film and a phase advance film are laminated. It is desirable as a material to be used. When the first film is a halftone phase shift film or a translucent laminated film, the content [at%] of the transition metal (M) in the film is the total content of the transition metal (M) and silicon (Si). The percentage [%] calculated by dividing by [at%] (hereinafter referred to as M / M + Si ratio) is preferably 35% or less, more preferably 25% or less, and 20 at% or less. Further preferred. Transition metals are elements that have a high extinction coefficient but also a high refractive index compared to silicon. If the refractive index of the material forming the first film is too high, the amount of phase change due to film thickness variation becomes large, and it becomes difficult to control both the phase and the transmittance.

  In addition, a material containing tantalum is also suitable as a material for forming the first film. A material containing tantalum has a high etching rate with respect to a fluorine-based gas, and has a relatively high resistance to dry etching with a mixed gas of a chlorine-based gas and an oxygen gas, and satisfies the etching characteristics required for the first film. be able to. Examples of the material containing tantalum that can be applied to the first film include tantalum metal and a material in which tantalum contains one or more elements selected from nitrogen, oxygen, boron, and carbon. For example, Ta, TaN, TaON, TaBN, TaBON, TaCN, TaCON, TaBCN, TaBOCN and the like can be mentioned. The material containing tantalum may further contain a metal other than tantalum as long as the etching characteristics required for the first film are not impaired.

  In the case where the first film is a light-shielding film in a transfer mask to which the double exposure technique is applied, configurations such as a single layer film and a multi-layer film can be applied. In the case of a laminated film, a laminated structure in which a light shielding layer formed of a material having a high optical density from the substrate side and a low reflective layer formed of a material having a relatively low optical density and having a function of reducing surface reflection are laminated. It is preferable to do. Since the material for forming the light shielding layer is required to have a high optical density, the oxygen content is less than 10 at% and the nitrogen content is 25 at% or less from each material suitable as the first film. It is preferable to select the material. The low reflection layer needs to transmit exposure light to some extent in order to reduce surface reflection. For this reason, as the material for forming the low reflection layer, a material having an oxygen content of 15 at% or more or a material having a nitrogen content of 30 at% or more is selected from the materials suitable for the first film. It is preferable.

  The material forming the first film is preferably resistant to dry etching using a mixed gas of chlorine-based gas and oxygen gas. After the fine pattern (first pattern) is formed on the first film, when the second pattern is formed on the second film, dry etching using a mixed gas of chlorine-based gas and oxygen gas is performed. At this time, if the first film has low resistance to dry etching by a mixed gas of chlorine-based gas and oxygen gas, the surface of the first film and the pattern side wall may be damaged. Dry etching using a mixed gas of chlorine-based gas and oxygen gas is a material containing silicon or a material containing silicon and a transition metal that contains more silicon than the transition metal. High resistance to

In the mask blank of the present invention, it is preferable that the first film has an oxide layer formed on the surface layer on the second film side. By providing the oxide layer, resistance to etching by a mixed gas of chlorine gas and oxygen gas used when dry etching the second film can be enhanced. When a material containing silicon or a material containing silicon and a transition metal is applied to the first film, if a silicon oxide layer is formed on the surface layer, a mixture of chlorine-based gas and oxygen gas is used. Resistance to etching by gas is greatly improved. The silicon oxide layer preferably has an oxygen content of 45 at% or more, and more preferably 50 at%. Further, when a material containing tantalum is applied to the first film, if a tantalum oxide layer is formed on the surface layer, the resistance to etching by a mixed gas of chlorine-based gas and oxygen gas is greatly improved. To do. The higher the tantalum oxide layer, the better the proportion of Ta ₂ O ₅ bonds in the film. The tantalum oxide film is desired to have an oxygen content of 60 at% or more in the film, preferably 66.7 at% or more, and more preferably 71.4 at% or more.

  The oxide layer formed on the surface layer of the first film preferably has a thickness of 1 nm to 4 nm. If it is less than 1 nm, it is too thin, and the effect of improving resistance to etching by a mixed gas of chlorine-based gas and oxygen gas is small. If it exceeds 4 nm, the influence on the optical characteristics of the first film (transmittance to exposure light, phase shift amount, optical density, EMF bias, etc.) becomes large, which is not preferable. The thickness of the oxide layer is more preferably 1 nm or more and 3 nm or less.

  In the mask blank of the present invention, it is preferable that the resist film is formed with a thickness of 100 nm or less in contact with the surface of the upper layer. In the case of a mask blank having a laminated structure of the first film and the second film of the present invention, a first pattern which is a fine pattern is formed on the first film even if the resist film has a thickness of 100 nm. can do. In the case of a fine pattern corresponding to the DRAM hp32 nm generation, SRAF (Sub-Resolution Assist Feature) having a line width of 40 nm may be provided in the first pattern to be formed in the first film. However, even in this case, since the cross-sectional aspect ratio of the resist pattern can be reduced to 1: 2.5, it is possible to suppress the resist pattern from collapsing or detaching during development or rinsing of the resist film. The resist film is more preferably 80 nm or less in thickness.

  The mask blank of the present invention has a laminated structure of the first film and the second film. This laminated structure preferably has an optical density of 2.8 or higher with respect to the exposure light of the ArF excimer laser. When a transfer mask is produced using this mask blank, a light shielding band can be provided in the outer peripheral region of the transfer mask. By forming the light shielding band with a laminated structure of the first film and the second film, the optical density of the light shielding band can be 2.8 or more. With such a transfer mask, it is possible to prevent the resist film on the semiconductor wafer from being affected by the exposure light transmitted through the outer peripheral area when the exposure apparatus is exposed and transferred to the resist film on the semiconductor wafer. it can. Further, it is more preferable that the optical density of the laminated structure of the first film and the second film with respect to the exposure light of the ArF excimer laser is 3.0 or more. Further, in the case of a mask blank used for producing a transfer mask to which the double exposure technique is applied, the optical density of the laminated structure of the first film and the second film with respect to the exposure light of the ArF excimer laser is 3 .3 or more is more preferable.

In the mask blank of the present invention, examples of the material of the substrate include synthetic quartz glass, quartz glass, aluminosilicate glass, soda lime glass, low thermal expansion glass (SiO ₂ —TiO ₂ glass, etc.) and the like. Synthetic quartz glass has a high transmittance with respect to ArF excimer laser light (wavelength 193 nm), and is particularly preferable as a material for forming a mask blank substrate (translucent substrate). The exposure light applied to the mask blank and transfer mask of the present invention can be ArF excimer laser light, KrF excimer laser light, i-line light, or the like, and is not particularly limited. Mask blanks and transfer masks that apply an ArF excimer laser to exposure light are particularly effective because they have a very high level of demand, such as the positional accuracy of a transfer pattern formed by a thin film.

  Etching made of a material (Cr-containing material such as Cr, CrN, CrC, CrO, CrON, CrC, etc.) having an etching selectivity with respect to the substrate and the first film between the substrate and the first film A stopper film or an etching mask film may be formed.

  The transfer mask of the present invention is produced using the mask blank of the present invention. For this reason, the various characteristics relating to the substrate, the first film, and the second film in the transfer mask are the same as those described for the mask blank of the present invention.

  In the method for manufacturing a transfer mask using the mask blank of the present invention, a resist film having a first pattern is formed in contact with the surface of the second film, and a dry gas using a mixed gas of chlorine-based gas and oxygen gas is used. A step of forming a first pattern on the second film by etching, and after removing the resist film having the first pattern, a fluorine-based gas is used with the second film having the first pattern as a mask. A step of forming the first pattern on the first film by dry etching, a resist film having the second pattern in contact with the surface of the second film, and a mixed gas of chlorine-based gas and oxygen gas And a step of forming a second pattern on the second film by dry etching using

  FIG. 1 is a cross-sectional view showing a configuration of a mask blank 100 according to the present invention. FIG. 2 is a cross-sectional view showing a manufacturing process of the transfer mask 200 using the mask blank 100. The mask blank 100 has a structure in which a first film 2 and a second film 3 are laminated on a substrate 1. The first film 2 has a structure in which an oxide layer 22 is formed on the surface layer opposite to the substrate 1 side (second film 3 side) (the first film 2 excluding the oxide layer 22 has a main body 21. ). The second film 3 has a configuration in which a lower layer 31 and an upper layer 32 are laminated. Details of each configuration of the mask blank 100 are as described above. Hereinafter, according to the manufacturing process shown in FIG. 2, the manufacturing method of the transfer mask will be described.

  First, the resist film 4 is formed in contact with the surface of the upper layer 32 of the second film 3 in the mask blank 100 (see FIG. 2A). Next, a first pattern, which is a transfer pattern (fine pattern) to be formed on the first film 2, is exposed and drawn on the resist film 4, and a predetermined process such as a development process is further performed. A resist film 4 having a pattern (first resist pattern 4a) is formed (see FIG. 2B). Subsequently, dry etching using a mixed gas of chlorine-based gas and oxygen gas is performed using the first resist pattern 4a as a mask to form the first pattern on the second film 3 (upper layer 32 and lower layer 31) ( Etching mask pattern 3a). Subsequently, the first resist pattern 4a is removed (see FIG. 2C).

  Next, dry etching using a fluorine-based gas is performed using the etching mask pattern 3a as a mask to form a first pattern (first film pattern 2a) on the first film 2 (see FIG. 2D). ). Next, a resist film 5 is formed in contact with the upper layer 32 of the second film 3. Next, the resist film 5 is exposed and drawn with a second pattern, which is a transfer pattern to be formed on the second film 3, and further subjected to a predetermined process such as a development process, whereby a resist having the second pattern is formed. A film 5 (second resist pattern 5a) is formed (see FIG. 2E). Using the second resist pattern 5a as a mask, dry etching using a mixed gas of chlorine gas and oxygen gas is performed to form a second pattern on the second film 3 (upper layer 32 and lower layer 31) (second Film pattern 3b) (see FIG. 2F). Then, the second resist pattern 5a is removed, and a transfer mask 200 is obtained through a predetermined process such as cleaning (see FIG. 2G).

The chlorine-based gas used in the dry etching is not particularly limited as long as it contains Cl. Examples of the chlorine-based gas include Cl ₂ , SiCl ₂ , CHCl ₃ , CH ₂ Cl ₂ , CCl ₄ , BCl _{3 and the} like. Moreover, the fluorine-type gas used by the said dry etching should just be a gas containing F, and there is no restriction | limiting in particular. Examples of the fluorine-based gas include CHF ₃ , CF ₄ , C ₂ F ₆ , C ₄ F ₈ , SF _{6 and the} like. In particular, since the fluorine-based gas not containing C has a relatively low etching rate with respect to the glass substrate, damage to the glass substrate can be further reduced.

  In the method for manufacturing the transfer mask, the upper layer 32 and the lower layer of the second film are formed by performing dry etching using a mixed gas of chlorine-based gas and oxygen gas using the first resist pattern 4a as a mask. A first pattern is formed on 31. However, the present invention is not limited to this, and dry etching using a mixed gas of a chlorine-based gas and an oxygen gas may be performed only in the upper layer 32 of the second film or in the middle of the lower layer 31 in the film thickness direction. In this case, after removing the first resist pattern 4a, dry etching using a fluorine-based gas is performed using the first pattern formed in the upper layer 32 of the second film as a mask, and the lower layer 31 of the second film. A first pattern is formed, and a first pattern is formed on the first film. By performing such a process, it is possible to further shorten the time for performing dry etching using a mixed gas of chlorine-based gas and oxygen gas using the first resist pattern 4a as a mask. The film thickness of 4a can be made thinner (for example, 50 nm or less).

  The semiconductor device manufacturing method of the present invention is characterized in that the first pattern is exposed and transferred onto a resist film on a semiconductor substrate using the transfer mask or the transfer mask manufactured using the mask blank. It is said. Since the first pattern, which is a fine pattern, is formed with high accuracy on the first film of the transfer mask used here, the first pattern is applied to the resist film on the semiconductor substrate with high transfer accuracy. Can be formed.

Hereinafter, the embodiment of the present invention will be described more specifically with reference to examples.
(Example 1)
[Manufacture of mask blanks]
A substrate 1 made of synthetic quartz glass having a main surface dimension of about 152 mm × about 152 mm and a thickness of about 6.25 m was prepared. This substrate 1 had its end face and main surface polished to a predetermined surface roughness and then subjected to a predetermined cleaning process and drying process.

Next, the substrate 1 is placed in a single-wafer DC sputtering apparatus, and a mixed target (Mo: Si = 12 at%: 88 at%) of molybdenum (Mo) and silicon (Si) is used, and argon (Ar), nitrogen is used. A first film 2 (MoSiN film Mo: 12 at%, Si) made of molybdenum, silicon and nitrogen is formed on the substrate 1 by reactive sputtering (DC sputtering) in a mixed gas atmosphere of (N ₂ ) and helium (He). : 39 at%, N: 49 at%) with a film thickness of 69 nm. The composition of the MoSiN film is a result obtained by Auger electron spectroscopy (AES). The same applies to other films.

  Next, a treatment for forming an oxide layer 22 on the surface layer of the first film 2 was performed on the substrate 1 on which the MoSiN film (first film 2) was formed. Specifically, using a heating furnace (electric furnace), heat treatment was performed in the atmosphere at a heating temperature of 450 ° C. and a heating time of 1 hour. When the first film 2 after the heat treatment is analyzed by Auger electron spectroscopy (AES), it is confirmed that the oxide layer 22 is formed with a thickness of about 1.5 nm from the surface of the first film 2. The oxygen content of the oxide layer 22 was 42 at%. When the transmittance and phase difference of the ArF excimer laser light at the wavelength (about 193 nm) were measured with respect to the MoSiN film (first film 2) after the heat treatment, the transmittance was 6.07. % And the phase difference was 177.3 degrees.

Next, the substrate 1 is installed in a single-wafer DC sputtering apparatus, using a molybdenum (Mo) target, and reactive sputtering (DC sputtering) in a mixed gas atmosphere of argon (Ar) and nitrogen (N ₂ ). In contact with the surface of the first film 2, a lower layer 31 (MoN film Mo: 64 at%, N: 36 at%) made of molybdenum and nitrogen was formed to a thickness of 16 nm.

Next, the substrate 1 is placed in a single-wafer DC sputtering apparatus, and a mixed gas of argon (Ar), carbon dioxide (CO ₂ ), nitrogen (N ₂ ), and helium (He) is used using a chromium (Cr) target. The upper layer 32 of the second film 3 made of chromium, oxygen, carbon and nitrogen (CrOCN film Cr: 34 at%, in contact with the surface of the lower layer 31 of the second film 3 by reactive sputtering (DC sputtering) in an atmosphere. O: 39 at%, C: 11 at%, N: 16 at%) was formed with a film thickness of 23 nm.

[Manufacture of transfer masks]
Next, using the mask blank 100 of Example 1, the transfer mask 200 of Example 1 was produced according to the following procedure. First, a resist film 4 made of a chemically amplified resist for electron beam drawing was formed to a thickness of 80 nm in contact with the surface of the upper layer 32 of the second film 3 by a spin coating method (see FIG. 2A). Next, a transfer pattern of DRAM hp 32 nm generation (a fine pattern including SRAF with a line width of 40 nm) is drawn on the resist film 4 by electron beam, predetermined development processing and cleaning processing are performed, and the first pattern is obtained. A resist film 4 (first resist pattern 4a) was formed (see FIG. 2B). Next, using the first resist pattern 4a as a mask, dry etching using a mixed gas of chlorine and oxygen (gas flow ratio Cl ₂ : O ₂ = 4: 1) is performed, and the second film 3 is subjected to the first etching. A pattern (etching mask pattern 3a) was formed. Subsequently, the first resist pattern 4a was removed (see FIG. 2C).

Next, using the etching mask pattern 3a as a mask, dry etching using a fluorine-based gas (SF ₆ + He) is performed to form a first pattern on the first film (halftone phase shift film) 2 (the first pattern Film pattern 2a) (see FIG. 2D). Next, a resist film 5 made of a chemically amplified resist for electron beam drawing was formed to a thickness of 80 nm in contact with the upper layer 32 of the second film 3 (see FIG. 2E).

Next, a second pattern, which is a transfer pattern to be formed on the second film 3, is drawn on the resist film 5 by electron beam, a predetermined development process and a cleaning process are performed, and the resist having the second pattern A film 5 (second resist pattern 5a) was formed (see FIG. 2E). Next, dry etching using a mixed gas of chlorine and oxygen (gas flow ratio Cl ₂ : O ₂ = 4: 1) is performed using the second resist pattern 5a as a mask, and the second film 3 (the upper layer 32 and A second pattern (second film pattern 3b) was formed on the lower layer 31) (see FIG. 2F). Finally, the second resist pattern 5a was removed, and after a predetermined process such as cleaning, a transfer mask (halftone phase shift mask) 200 was obtained (see FIG. 2G). When the mask pattern was inspected by the mask inspection apparatus on the transfer mask (halftone type phase shift mask) 200 of Example 1 produced, it was found that a fine pattern was formed within the allowable range from the design value. It could be confirmed.

[Manufacture of semiconductor devices]
The produced transfer mask (halftone phase shift mask) 200 of Example 1 is set on a mask stage of an exposure apparatus using an ArF excimer laser as exposure light, and a first film pattern 2a is formed on a resist film on a semiconductor device. Was transferred by exposure. A predetermined development process was performed on the resist film on the semiconductor device after exposure to form a resist pattern, and the lower layer film was dry-etched using the resist pattern as a mask to form a circuit pattern. When the circuit pattern formed in the semiconductor device was confirmed, there was no wiring short circuit or disconnection of the circuit pattern due to insufficient accuracy.

(Comparative Example 1)
[Manufacture of mask blanks]
A substrate made of synthetic quartz glass having a main surface dimension of about 152 mm × about 152 mm and a thickness of about 6.25 m was prepared in the same procedure as in Example 1. Next, a MoSiN film (film corresponding to the first film 2 of Example 1) is formed on the substrate in the same procedure as in Example 1, and heat treatment is performed to form an oxide layer on the surface of the MoSiN film. Formed.

Next, the substrate 1 is installed in a single-wafer DC sputtering apparatus, and a reactive sputtering is performed in a mixed gas atmosphere of argon (Ar), carbon dioxide (CO ₂ ), and nitrogen (N ₂ ) using a chromium (Cr) target. A CrOCN film (Cr: 37 at%, O: 38 at%, C: 16 at%, N: 9 at%) made of chromium, oxygen, carbon and nitrogen is in contact with the surface of the first film 2 by (DC sputtering). The film was formed with a thickness of 30 nm. Subsequently, a CrN film (Cr: 79 at%, N: 21 at%) made of chromium and nitrogen was formed to a thickness of 4 nm by reactive sputtering in a mixed gas atmosphere of argon (Ar) and nitrogen (N ₂ ). Finally, a CrOCN film (Cr: 35 at%, O: 38 at) made of chromium, oxygen, carbon and nitrogen is formed by reactive sputtering in a mixed gas atmosphere of argon (Ar), carbon dioxide (CO ₂ ), and nitrogen (N ₂ ). %, C: 10 at%, N: 17 at%) with a film thickness of 14 nm. By the above procedure, a Cr-based laminated film (a film corresponding to the second film 3 of Example 1) in which a CrOCN film, a CrN film, and a CrOCN film are sequentially laminated is provided in contact with the surface of the first film 2. The mask blank of Comparative Example 1 was manufactured.

[Manufacture of transfer masks]
Next, using the mask blank of Comparative Example 1, a transfer mask of Comparative Example 1 was produced according to the following procedure. First, a resist film made of a chemically amplified resist for electron beam drawing was formed with a thickness of 80 nm in contact with the surface of the Cr-based laminated film by spin coating. Next, a transfer pattern of DRAM hp 32 nm generation (a fine pattern including SRAF with a line width of 40 nm) is drawn on the resist film by electron beam, predetermined development processing and cleaning processing are performed, and the resist having the first pattern A film (first resist pattern) was formed. Next, using the first resist pattern as a mask, a mixed gas of chlorine and oxygen (gas flow ratio Cl ₂ : O ₂ = 4: 1) is used to form the first pattern (etching mask pattern) on the Cr-based laminated film. Dry etching was performed to form. However, the first resist pattern disappeared while the Cr-based laminated film was being etched, and the first pattern could not be formed. For this reason, the first pattern could not be formed on the MoSiN film.

DESCRIPTION OF SYMBOLS 1 Substrate 2 1st film | membrane 21 Main-body part 22 Oxide layer 2a 1st film | membrane pattern 3 2nd film | membrane 31 Lower layer 32 Upper layer 3a Etching mask pattern 3b 2nd film | membrane pattern 4, 5 Resist film 4a 1st resist pattern 5a Second resist pattern 100 Mask blank 200 Transfer mask

Claims (23)

A mask blank having a structure in which a first film and a second film are sequentially laminated on a substrate from the substrate side, which is used for producing a transfer mask;
The first film is made of a material that can be dry-etched with a fluorine-based gas,
The second film has a laminated structure of a lower layer and an upper layer,
The lower layer is made of a material containing at least one of molybdenum and tungsten and having a silicon content of 0 at% or more and less than 10 at%,
The upper layer is made of a material containing chromium and oxygen, a chromium content of less than 50 at%, and an oxygen content of 25 at% or more. The mask blank according to claim 1, wherein the lower layer is made of a material containing at least one of molybdenum and tungsten and not containing silicon.   The mask blank according to claim 1, wherein the lower layer is made of a material further containing nitrogen. The mask blank according to any one of claims 1 to 3, wherein the lower layer is made of a material having an oxygen content of 30 at% or less. The second film, the mask blank according to any one of claims 1 to 4, characterized in that dry etching using a mixed gas of chlorine gas and oxygen gas formed of a material as possible. The first film is made of a material containing silicon, or a material containing silicon and a transition metal, wherein the silicon content is higher than the transition metal content. Item 6. A mask blank according to any one of Items 1 to 5 . The first film is a mask blank according to any one of claims 1 to 6, characterized in that the oxide layer in the surface layer of the second film side. The mask blank according to any one of claims 1 to 7 , wherein a resist film is formed with a thickness of 100 nm or less in contact with the surface of the upper layer. The laminated structure of the first film and the second film, the mask blank according to any one of claims 1 to 8, the optical density with respect to the ArF exposure light, characterized in that 2.8 or more. The first film is a mask blank according to any one of claims 1-9, wherein the transmittance to ArF exposure light is a light semi-transmitting film of 1% or more. A transfer mask in which a first film having a first pattern and a second film having a second pattern are sequentially stacked on a substrate from the substrate side,
The first film is made of a material that can be dry-etched with a fluorine-based gas,
The second film has a laminated structure of a lower layer and an upper layer,
The lower layer is made of a material containing at least one of molybdenum and tungsten and having a silicon content of 0 at% or more and less than 10 at%,
The transfer mask according to claim 1, wherein the upper layer is made of a material containing chromium and oxygen, a chromium content of less than 50 at%, and an oxygen content of 25 at% or more. 12. The transfer mask according to claim 11 , wherein the lower layer is made of a material containing at least one of molybdenum and tungsten and not containing silicon. The lower layer, transfer mask according to claim 11 or 12, characterized in that it consists of a material further containing nitrogen. The transfer mask according to claim 11, wherein the lower layer is made of a material having an oxygen content of 30 at% or less. The second film, transfer mask according to any of claims 11 to 14, characterized in that dry etching using a mixed gas of chlorine gas and oxygen gas formed of a material as possible. The first film is made of a material containing silicon, or a material containing silicon and a transition metal, wherein the silicon content is higher than the transition metal content. Item 16. A transfer mask according to any one of Items 11 to 15 . The first film is transfer mask according to any one of claims 11 16, characterized in that the oxide layer in the surface layer of the second film side. The laminated structure of the first film and the second film, transfer mask according to any one of claims 11 to 17, the optical density with respect to the ArF exposure light, characterized in that 2.8 or more. The first film is transfer mask according to any one of claims 11 18, wherein the transmittance to ArF exposure light is a light semi-transmitting film of 1% or more. A method for manufacturing a transfer mask using the mask blank according to any one of claims 1 to 10 ,
A resist film having a first pattern is formed in contact with the surface of the second film, and the first pattern is formed on the second film by dry etching using a mixed gas of chlorine-based gas and oxygen gas. And a process of
Step of forming the first pattern on the first film by removing the resist film having the first pattern and then using the second film having the first pattern as a mask by dry etching using a fluorine-based gas When,
A resist film having a second pattern is formed in contact with the surface of the second film, and a second pattern is formed on the second film by dry etching using a mixed gas of chlorine-based gas and oxygen gas. And a process for producing a transfer mask. 21. The method of manufacturing a transfer mask according to claim 20 , wherein the resist film having the first pattern has a thickness of 100 nm or less. Using the transfer mask according to any of claims 11 19, a method of manufacturing a semiconductor device characterized by comprising the step of exposing and transferring a first pattern to the resist film on a semiconductor substrate. A process for exposing and transferring a first pattern onto a resist film on a semiconductor substrate using the transfer mask manufactured by the method for manufacturing a transfer mask according to claim 20 or 21 . Production method.

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