KR101916498B1 - Phase shift mask blank and manufacturing method therefor, method for manufacturing phase shift mask - Google Patents

Abstract

The present invention relates to a phase shift mask blank capable of patterning a phase shift film in a cross-sectional shape capable of sufficiently exhibiting a phase shift effect by wet etching, a method of manufacturing the same, and a phase shift film having a phase shift film pattern capable of sufficiently exhibiting a phase shift effect And a method of manufacturing a mask. The phase shift mask blank 1 is formed by forming a phase shift film 3 containing chromium, oxygen and nitrogen on a transparent substrate 2. In the phase shift film 3, a composition gradient region R1 is formed from the outermost surface 3a toward the film depth direction. In the composition gradient region R1, the maximum value of the ratio of oxygen (O / Cr) to chromium which decreases from the outermost surface 3a toward the film depth direction is 2 or more, The maximum value of the ratio (N / Cr) of nitrogen to decreasing chromium is 0.45 or less.

Description

[0001] PHASE SHIFT MASK BLANK AND MANUFACTURING METHOD THEREFOR, METHOD FOR MANUFACTURING PHASE SHIFT MASK [0002] BACKGROUND OF THE INVENTION [0003]

The present invention relates to a phase shift mask blank for manufacturing a display device, a method of manufacturing the same, and a method of manufacturing a phase shift mask for manufacturing a display device using the phase shift mask blank.

At present, VA (Vertical Alignment) method or IPS (In Plane Switching) method is used as a method adopted for a liquid crystal display device. By these methods, realization of a liquid crystal display device with high precision, high-speed display performance, and wide viewing angle is being realized. In the liquid crystal display device to which these methods are applied, the response speed and the viewing angle can be improved by forming the pixel electrode in a line-and-space pattern of the transparent conductive film. In recent years, from the viewpoints of further improving the response speed and the viewing angle, and improving the light utilization efficiency of the liquid crystal display device, that is, lowering power consumption and improving contrast of the liquid crystal display device, it is required to miniaturize the pitch width of the line- have. For example, it is desired to narrow the pitch width (sum of the line width L and the space width S) of the line-and-space pattern from 6 탆 to 5 탆 and from 5 탆 to 4 탆. In this case, at least one of the line width L and the space width S is often less than 3 mu m. For example, it is often the case that L < 3 mu m, or L &amp;le; 2 mu m, or S &lt;

When a liquid crystal display device or an organic EL display device is manufactured, elements such as transistors are formed by laminating a plurality of conductive films and insulating films which are subjected to necessary patterning. At that time, a photolithography process is often used for patterning individual films to be laminated. For example, as a thin film transistor ("TFT") used in these display devices, among the plurality of patterns constituting the TFT, the contact hole formed in the passivation (insulating layer) penetrates the insulating layer, And a connection portion on the lower layer side is made conductive. At this time, if the pattern of the upper layer side and the pattern of the lower layer side are accurately positioned, and the shape of the contact hole can not be reliably formed, correct operation of the display device is not guaranteed. Also here, with the improvement of the display performance, the high integration of the device pattern is required, and the pattern is required to be miniaturized. That is, the diameter of the hole pattern also needs to be less than 3 탆. For example, a hole pattern having a diameter of 2.5 占 퐉 or less and a diameter of 2.0 占 퐉 or less is required, and it is considered that a pattern having a diameter of 1.5 占 퐉 or less which is lower than this is desired in the near future.

From such a background, there is a demand for a photomask for manufacturing a display device capable of coping with line-and-space patterns and miniaturization of contact holes.

In realizing the line-and-space pattern and the contact hole miniaturization, since the resolving limit of the exposure apparatus for manufacturing a display device is 3 μm in the conventional photomask, the minimum value close to the marginal limit It must produce line width products. As a result, there has been a problem that the defective rate of the display device is increased.

For example, in the case of using a photomask having a hole pattern for forming a contact hole and considering transferring the photomask to a subject, a hole pattern having a diameter exceeding 3 mu m can be transferred by a conventional photomask. However, it is very difficult to transfer a hole pattern having a diameter of 3 탆 or less, particularly, a hole pattern having a diameter of 2.5 탆 or less. In order to transfer a hole pattern having a diameter of 2.5 mu m or less, it is conceivable to switch to, for example, an exposure machine having a high NA, but a large investment is required.

Therefore, a phase shift mask has attracted attention as a photomask for manufacturing a display device in order to cope with miniaturization of a line-and-space pattern and a contact hole by improving the resolution.

In recent years, as a photomask for manufacturing a liquid crystal display device, a phase shift mask having a chromium phase shift film has been developed.

Patent Document 1 discloses that it is possible to have a phase difference of 180 degrees with respect to light of any one of a transparent substrate, a light-shielding layer formed on the transparent substrate, and a wavelength region of 300 nm or more and 500 nm or less formed around the light- There is disclosed a halftone phase shift mask having a phase shift layer made of a chromium oxynitride material. This phase shift mask is formed by patterning a light shielding layer on a transparent substrate, forming a phase shift layer on the transparent substrate so as to cover the light shielding layer, forming a photoresist layer on the phase shift layer, exposing and developing the photoresist layer Forming a resist film pattern, and patterning the phase shift layer using the resist film pattern as an etching mask.

Japanese Patent Application Laid-Open No. 11-13283

The inventors of the present invention have studied the phase shift mask with a chromium phase shift film. As a result, when the chromium-based phase shift film was patterned by wet etching using the resist film pattern as a mask, it was found that the wet etching solution penetrated the interface between the resist film and the chromium phase shift film and the etching of the interface portion progressed rapidly . As a result, the cross-sectional shape of the edge portion of the chromium-based phase shift film pattern formed was inclined over the entire edge portion, and became tapered so as to be drawn toward the transparent substrate.

When the cross-sectional shape of the edge portion of the chromium-based phase shift film pattern is tapered, the phase shift effect decreases as the film thickness of the edge portion of the chromium phase shift film pattern decreases. As a result, the chrome phase shift film pattern can not sufficiently exhibit the phase shift effect. The penetration of the wet etching solution into the interface between the resist film and the chromium phase shift film is caused by poor adhesion between the chromium phase shift film and the resist film. As a result, it is difficult to strictly control the cross-sectional shape of the edge portion of the chrome phase shift film pattern, so that resolution is not sufficiently obtained and it is very difficult to control the line width CD.

In order to solve these problems, the present inventors have extensively studied a method of vertically making the cross-sectional shape of the edge portion of the chromium phase shift film pattern. So far, for example, by adjusting the content of nitrogen which accelerates the etching rate or the content of carbon which slows down the etching rate, the film composition of the chromium phase shift film is inclined so as to change the etching rate in the film thickness direction Method was developed. However, in this method, it is very difficult to realize the uniformity of the transmittance throughout the large-area phase shift mask.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a phase shift mask blank capable of patterning a phase shift film in a cross-sectional shape capable of sufficiently exhibiting a phase shift effect by wet etching, And a method of manufacturing a phase shift mask having a phase shift film pattern which can be sufficiently exposed.

In order to solve the above-described problems, the present invention has the following configuration.

(Structure 1) A phase shift mask blank in which a phase shift film containing chromium, oxygen and nitrogen is formed on a transparent substrate,

A composition gradient region is formed in the phase shift film from the outermost surface thereof toward the film depth direction, and a ratio (O / Cr) of oxygen to chromium decreases from the outermost surface toward the film depth direction in the composition gradient region Wherein the maximum value is 2 or more and the maximum value of the ratio of nitrogen to chromium (N / Cr) decreasing from the outermost surface toward the film depth direction is 0.45 or less.

(Composition 2) The phase shift mask blank according to Structure 1, wherein the composition gradient region of the phase shift film is formed by vacuum ultraviolet ray irradiation processing on the outermost surface.

(Composition 3) The phase shift mask blank according to configuration 1 or 2, wherein the film density of the outermost surface of the phase shift film is 2.0 g / cm 3 or more.

(Composition 4) The phase shift mask blank according to any one of Structures 1 to 3, wherein the film thickness of the composition gradient region is 0.1 nm or more and 10 nm or less.

(Constitution 5) The phase shift film according to any one of Structures 1 to 4, wherein the composition ratio of each element in the film depth direction in the phase shift film except for the composition gradient region and the region near the transparent substrate is substantially uniform Shift mask blank.

(Constitution 6) The phase shift mask blank according to any one of Structures 1 to 5, wherein the phase shift film further contains carbon.

(Structure 7) A manufacturing method of a phase shift mask blank in which a phase shift film containing chromium, oxygen, and nitrogen is formed on a transparent substrate by a sputtering method,

A film forming step of forming the phase shift film on the transparent substrate;

And a vacuum ultraviolet ray irradiation processing step of performing vacuum ultraviolet ray irradiation processing on the outermost surface of the phase shift film that has been formed,

Wherein the vacuum ultraviolet ray irradiation treatment step includes a step of irradiating the surface of the phase shift film with a composition ratio of oxygen to chromium which decreases from the outermost surface toward the film depth direction in a composition gradient region formed from the outermost surface of the phase shift film toward the film depth direction, Cr) is changed to 2 or more, and the maximum value of the ratio of nitrogen (N / Cr) to chromium which decreases from the outermost surface toward the film depth direction is changed to 0.45 or less. Gt;

(Constitution 8) The manufacturing method of the phase shift mask blank according to Structure 7, wherein the vacuum ultraviolet ray irradiation treatment step changes the film density of the outermost surface of the phase shift film to 2.0 g / cm 3 or more.

(Composition 9) The phase shift mask blank according to Structure 7 or 8, wherein the composition ratio of each element in the film depth direction in the phase shift film except for the composition gradient region and the vicinity of the transparent substrate is substantially uniform. &Lt; / RTI &gt;

(Constitution 10) The manufacturing method of a phase shift mask blank according to any one of Structures 7 to 9, wherein the film forming step is a step of laminating the same material to form the phase shift film.

(Constitution 11) The film formation step is carried out by reactive sputtering with a mixed gas containing an inert gas and an active gas for oxidizing and nitriding the phase shift film, using a sputtering target containing chromium. A method for manufacturing a phase shift mask blank according to any one of 7 to 10.

(Composition 12) The method for producing a phase shift mask blank according to Structure 11, wherein the mixed gas further comprises an active gas for carbonizing the phase shift film.

(Composition 13) The production method of a phase shift mask blank according to Structure 11 or 12, wherein the film forming step is performed by an in-line sputtering apparatus.

(Configuration 14) A manufacturing method of a phase shift mask blank according to Structure 13, wherein the mixed gas is supplied from the downstream side to the sputtering target in the transport direction of the transparent substrate in the vicinity of the sputtering target .

(Constitution 15) In the vacuum ultraviolet ray irradiation treatment step, the decreasing rate of the ratio of oxygen (O / Cr) to chromium in the composition gradient region is made larger after the vacuum ultraviolet ray irradiation treatment than before the vacuum ultraviolet ray irradiation treatment, The method of manufacturing a phase shift mask blank according to any one of structures 7 to 14, wherein the reduction ratio of nitrogen to chromium (N / Cr) is made smaller after the vacuum ultraviolet ray irradiation treatment than before the vacuum ultraviolet ray irradiation treatment.

(Constitution 16) A resist film is formed on the phase shift film of the phase shift mask blank produced by the phase shift mask blank according to any one of Structures 1 to 6 or the method for manufacturing a phase shift mask blank according to any one of Structures 7 to 15, Forming a film pattern on the transparent substrate and wet-etching the phase shift film using the resist film pattern as a mask to form a phase shift film pattern on the transparent substrate.

As described above, according to the phase shift mask blank of the present invention, a phase shift film containing chromium, oxygen and nitrogen is formed on a transparent substrate. In this phase shift film, a composition gradient region is formed from the outermost surface toward the film depth direction. In the composition gradient region, the ratio (O / Cr) of oxygen to chromium decreases from the outermost surface toward the film depth direction. And the maximum value of the ratio of nitrogen (N / Cr) to chromium which decreases from the outermost surface toward the film depth direction is 0.45 or less. Thus, this phase shift mask blank can be patterned into a cross-sectional shape such that the phase shift film can sufficiently exhibit a phase shift effect by wet etching. This phase shift mask blank has a sectional shape of an edge portion of the phase shift film pattern obtained by patterning the phase shift film so as to have a sectional shape capable of sufficiently exhibiting a phase shift effect, The phase shift film having the phase shift film pattern having the phase shift film pattern having the phase shift film pattern.

According to the method of manufacturing a phase shift mask blank according to the present invention, a phase shift film containing chromium, oxygen, and nitrogen is formed on a transparent substrate by a sputtering method. The phase shift film is formed on the outermost surface of the phase shift film And a vacuum ultraviolet ray irradiation treatment process for performing vacuum ultraviolet ray irradiation treatment. In this vacuum ultraviolet ray irradiation treatment step, the ratio of oxygen to chromium which decreases from the outermost surface toward the depth of the film in the composition gradient region (O / Cr) is changed to 2 or more and the maximum value of the ratio of nitrogen (N / Cr) to chromium which decreases from the outermost surface toward the film depth direction is changed to 0.45 or less. Thus, by the wet etching, a phase shift mask blank in which the phase shift film can be patterned in a cross-sectional shape capable of sufficiently exhibiting the phase shift effect can be manufactured. The cross sectional shape of the edge portion of the phase shift film pattern can be made to have a sectional shape capable of sufficiently exhibiting the phase shift effect. Thus, the phase shift mask blank capable of patterning the phase shift film pattern having good CD characteristics, Can be produced.

Further, according to the method of manufacturing a phase shift mask according to the present invention, a phase shift mask is manufactured using the above-mentioned phase shift mask blank. This makes it possible to manufacture a phase shift mask having a phase shift film pattern capable of sufficiently exhibiting a phase shift effect. Since the phase shift film pattern can sufficiently exhibit the phase shift effect, it is possible to manufacture a phase shift mask having a phase shift film pattern having good CD characteristics by improving the resolution. This phase shift mask can cope with the miniaturization of a line-and-space pattern or a contact hole.

1 is a cross-sectional view showing the configuration of a phase shift mask blank according to Embodiment 1 of the present invention.
2 (a) and 2 (b) are cross-sectional views showing respective steps of the method of manufacturing the phase shift mask blank shown in Fig.
3 is a schematic view showing an in-line sputtering apparatus usable for forming a phase shift mask blank.
4 (a) to 4 (e) are cross-sectional views showing respective steps of a method of manufacturing a phase shift mask according to Embodiment 2 of the present invention.
5 is a cross-sectional view showing a configuration of a phase shift mask blank according to Embodiment 3 of the present invention.
6 (a) to 6 (g) are cross-sectional views showing respective steps of the manufacturing method of the phase shift mask blank shown in Fig.
7A to 7E are cross-sectional views showing respective steps of a method of manufacturing a phase shift mask according to Embodiment 4 of the present invention.
Fig. 8 is a view showing a composition analysis result in the depth direction of the phase shift mask of the phase shift mask blank of Comparative Example 1. Fig.
9 is a view showing a result of composition analysis in the depth direction of the phase shift mask of the phase shift mask blank of Example 1. Fig.
10 is a diagram showing the relationship between the oxygen ratio (O / Cr) to the chromium and the film depth for the phase shift mask blank of the first embodiment and the phase shift mask blank of the first comparative example.
11 is a diagram showing the relationship between the ratio of nitrogen (N / Cr) to chromium and the film depth for the phase shift mask blank of Example 1 and the phase shift mask blank of Comparative Example 1. Fig.
12 is a cross-sectional photograph showing the cross-sectional shape of the edge portion of the phase shift film pattern of Example 1. Fig.
13 is a cross-sectional photograph showing the cross-sectional shape of the edge portion of the phase shift film pattern of the phase shift mask of Comparative Example 1. Fig.
14 is a cross-sectional view for explaining the cross-sectional angle in the cross section of the edge portion of the phase shift film pattern of the phase shift mask.
15 is a cross-sectional photograph showing the cross-sectional shape of the edge portion of the phase shift film pattern of the phase shift mask of Example 2. Fig.
16 is a cross-sectional photograph showing the cross-sectional shape of the edge portion of the phase shift film pattern of the phase shift mask of Comparative Example 2. Fig.

Hereinafter, a phase shift mask blank according to an embodiment of the present invention, a method of manufacturing the same, and a method of manufacturing a phase shift mask using the phase shift mask blank will be described in detail.

Embodiment 1

In Embodiment 1, a phase shift mask blank (transparent substrate / phase shift film) for manufacturing a display device and a manufacturing method thereof will be described.

FIG. 1 is a cross-sectional view showing the structure of a phase shift mask blank according to Embodiment 1 of the present invention, and FIGS. 2 (a) and 2 (b) FIG. 3 is a schematic view showing an in-line sputtering apparatus usable for forming a phase shift mask blank. FIG.

The phase shift mask blank 1 of Embodiment 1 has a structure in which a phase shift film 3 containing chromium, oxygen and nitrogen is formed on a transparent substrate 2 as shown in Fig.

The method of manufacturing the phase shift mask blank 1 according to the first embodiment thus configured is a method of manufacturing a phase shift mask blank 1 comprising a preparation step of preparing a transparent substrate 2 and a step of forming a chromium film by sputtering on the main surface of the transparent substrate 2, (Hereinafter also referred to as a "phase shift film forming process") for forming a phase shift film 3 containing a phase shift film 3 and a vacuum ultraviolet ray (Hereinafter referred to as &quot; VUV &quot;) irradiation process.

Hereinafter, each step will be described in detail.

1. Preparation process

First, the transparent substrate 2 is prepared.

The material of the transparent substrate 2 is not particularly limited as long as it is a material having translucency to the exposure light to be used. For example, synthetic quartz glass, soda lime glass, and alkali-free glass.

2. Phase shift film forming process

Next, as shown in Fig. 2A, a phase shift film 3 containing chromium, oxygen and nitrogen is formed on the main surface of the transparent substrate 2 by sputtering.

Specifically, in this phase shift film forming step, a sputtering target containing chromium is used to apply sputtering power, and reactive sputtering with a mixed gas containing an inert gas and an active gas for oxidizing and nitriding the phase shift film A film forming step of forming a phase shift film 3 containing chromium, oxygen and nitrogen is performed.

The phase shift film 3 has a property of changing the phase of exposure light (phase shift effect). Due to this property, a predetermined retardation occurs between the exposure light transmitted through the phase shift film 3 and the exposure light transmitted through only the transparent substrate 2. When the exposure light is composite light containing light in a wavelength range of 300 nm to 500 nm, the phase shift film 3 is formed so as to generate a predetermined retardation with respect to light of a representative wavelength. For example, when the exposure light is composite light including i-line, h-line and g-line, the phase shift film 3 is formed so as to generate a phase difference of 180 ° with respect to any one of the i-line, h- do. Further, in order to exhibit the phase shift effect, for example, the phase difference of the phase shift film 3 in the i-line is set in the range of 180 ° ± 10 °, and preferably set to approximately 180 °. Further, for example, the transmittance of the phase shift film 3 in i-line is preferably set in a range of 1% or more and 20% or less. Particularly, the film quality of the outermost surface of the phase shift film 3 is influenced by the vacuum ultraviolet ray irradiation treatment as described later, and as a result, the phase shift film 3 having a cross-sectional shape capable of sufficiently exhibiting a phase effect in patterning of the phase shift film by wet etching , It is preferable that the film composition of the phase shift film 3 in the i-line is set to a film ratio set in the range of 3% or more and 15% or less.

The phase shift film 3 is made of a chromium-based material containing at least chromium (Cr), oxygen (O), and nitrogen (N). The chromium-based material may further contain carbon (C), if necessary, in addition to the above three elements. When a chromium-based material containing carbon is used, the tolerance and cleaning resistance of the phase shift film 3 can be improved.

Concretely, as the chromium-based material constituting the phase shift film 3, chromium oxide nitride (CrON) and chromium carbonized oxynitride (CrCON), for example, can be mentioned. The chromium-based material may contain hydrogen (H) and fluorine (F) within a range not deviating from the effect of the present invention.

The phase shift film 3 can be formed by, for example, a sputtering target and a sputter gas atmosphere as described below.

As the sputtering target used for forming the phase shift film 3, one containing chromium (Cr) is selected. Specifically, examples thereof include chromium (Cr), a nitride of chromium, an oxide of chromium, a carbide of chromium, an oxynitride of chromium, a carbonitride of chromium, an oxide carbide of chromium, and an oxide carbonitride of chromium.

The sputter gas atmosphere at the time of forming the phase shift film 3 is composed of an inert gas and a mixed gas containing an active gas for oxidizing and nitriding the phase shift film. Examples of the inert gas include helium (He) gas, neon (Ne) gas, argon (Ar) gas, krypton (Kr) gas and xenon (Xe) gas. At least one gas among these gases is selected. Examples of the active gas include oxygen (O ₂ ) gas, nitrogen (N ₂ ) gas, nitrogen monoxide (NO) gas, nitrogen dioxide (NO ₂ ) gas and nitrous oxide (N ₂ O) The carbon monoxide (CO) gas, the carbon dioxide (CO ₂ ) gas, and the hydrocarbon-based gas may be used as the carbonization activating gas. And at least one of these gases is selected as the hydrocarbon gas, and examples of the hydrocarbon gas include methane gas, butane gas, propane gas and styrene gas. For example, a CF ₄ gas, a CHF ₃ gas, an SF ₆ gas, or a mixture of these gases with an O ₂ gas, as the fluorine-based gas Number have.

The combination of the above-described material for forming the sputtering target and the gas type of the sputter gas atmosphere or the mixing ratio of the active gas and the inert gas in the sputter gas atmosphere is appropriately determined according to the type and composition of the material constituting the phase shift film 3 All.

The film thickness of the phase shift film 3 is appropriately adjusted in the range of 80 nm to 180 nm so as to obtain desired optical characteristics (phase difference).

The phase shift film 3 may be either a single-layer film or a laminate film. In the case where the phase shift film 3 is a laminated film, the compositions are made to coincide with each other at the interface between the layers, for example, the etch rate at the time of wet etching is made constant, thereby preventing the occurrence of so- It is preferable to form the phase shift film 3 by laminating the same material. In the case of the laminated film, it is preferable that the film formation step of the phase shift film 3 is performed plural times under the same film forming conditions. It is preferable that the film forming process for a plurality of times is performed continuously in the same sputtering apparatus. In the case where a plurality of film formation steps are continuously performed, it is preferable to use an in-line sputtering apparatus as described later. In addition, when the film forming process is performed a plurality of times, the sputter power applied to the sputtering target at the time of forming the phase shift film 3 can be reduced.

Such a phase shift film forming process can be performed using, for example, the in-line sputtering apparatus 11 shown in Fig.

The sputtering apparatus 11 is of an in-line type and consists of five chambers of a carry-in chamber LL, a first sputter chamber SP1, a buffer chamber BU, a second sputter chamber SP2 and a carry-out chamber ULL. These five chambers are successively arranged in order.

The transparent substrate 2 mounted on a tray (not shown) is moved in the direction of the arrow S by a predetermined conveyance speed in the direction of the arrow S from the transfer chamber LL, the first sputter chamber SP1, the buffer chamber BU, the second sputter chamber SP2, ULL. &Lt; / RTI &gt; The transparent substrate 2 mounted on a tray (not shown) is arranged in the order of the take-out chamber ULL, the second sputter chamber SP2, the buffer chamber BU, the first sputter chamber SP1 and the carry-in chamber LL Can be reversed.

The carry-in chamber LL and the first sputter chamber SP1, the second sputter chamber SP2 and the carry-out chamber ULL are partitioned by a partition plate. Further, the carry-in chamber LL and the carry-out chamber ULL can be partitioned from the outside of the sputtering apparatus 11 by the partition plate.

The carry-in chamber LL, the buffer chamber BU and the carry-out chamber ULL are connected to an evacuating device (not shown) for evacuating.

The first sputtering target SP1 is provided with a first sputtering target 13 containing chromium for forming the phase shift film 3 on the side of the bring-in chamber LL. The first sputtering target SP1 is transparent The first gas inlet port GA11 is disposed at a position on the upstream side of the first sputtering target 13 in the conveying direction indicated by the arrow S of the substrate 2 and the downstream side of the first sputtering target 13 The second gas inlet GA12 is disposed. A second sputtering target 14 including chromium for forming the phase shift film 3 is disposed in the buffer chamber BU side in the first sputtering chamber SP1 and a second sputtering target 14 is disposed in the vicinity of the second sputtering target 14 in the buffer chamber BU side. The third gas inlet port GA21 is disposed on the upstream side of the transparent substrate 2 in the conveying direction indicated by the arrow S with respect to the second sputtering target 14 and the downstream side with respect to the second sputtering target 14 The fourth gas inlet port GA22 is disposed at the position of the second gas inlet port GA22.

The gap between the first sputtering target 13 and the second gas inlet GA12 on the downstream side is set wider than the interval between the first sputtering target 13 and the first gas inlet G11 on the upstream side. Similarly, the distance between the second sputtering target 14 and the fourth gas inlet port GA22 on the downstream side is set to be wider than the interval between the second sputtering target 14 and the third gas inlet port GA21 on the upstream side.

In the first sputtering chamber SP1, the gap between the sputtering target and the gas introduction port on the downstream side is set to, for example, 15 cm or more and 50 cm or less, and the gap between the sputtering target and the gas introduction port on the upstream side is, It is preferably set to be not less than 1 cm and not more than 5 cm.

A third sputtering target 15 including chromium for forming the phase shift film 3 is disposed on the buffer chamber BU side in the second sputtering chamber SP2 and a third sputtering target 15 including chromium The fifth gas inlet port GA31 is disposed at a position on the upstream side of the third sputtering target 15 in the transport direction indicated by the arrow S of the substrate 2 and the downstream side of the third sputtering target 15 A sixth gas inlet port GA32 is disposed.

Here, as in the case of the first sputter chamber SP1, the interval between the third sputtering target 15 and the fifth gas inlet port GA31 on the downstream side is set to be shorter than the interval between the third sputtering target 15 and the sixth gas inlet port GA32 on the upstream side As shown in FIG.

Also in the second sputter chamber SP2, as in the case of the first sputter chamber SP1, the gap between the sputtering target and the gas inlet at the downstream side is set to, for example, 15 cm or more and 50 cm or less, The interval between the introduction ports is preferably set to, for example, 1 cm or more and 5 cm or less.

In FIG. 3, hatching is shown for the first sputtering target 13, the second sputtering target 14 and the third sputtering target 15.

Here, the case where the phase shift film 3 made of a single-layer film is formed (one-time film formation) will be described.

First, the transparent substrate 2 mounted on a tray (not shown) is loaded into the loading chamber LL of the sputtering apparatus 11. Then,

Next, after the inside of the sputtering apparatus 11 is set to a predetermined degree of vacuum, for example, a sputter gas at a predetermined flow rate is supplied from the second gas inlet GA12 on the downstream side of the first sputtering target 13 to the first sputtering chamber 13, SP1, and a predetermined sputtering power is applied to the first sputtering target 13. [0051] The application of the sputtering power and the introduction of the sputter gas continue until the transparent substrate 2 is transported to the discharge chamber ULL.

Thereafter, the transparent substrate 2 mounted on a tray (not shown) is transported at a predetermined transporting speed in the direction of the arrow S to the transfer chamber LL, the first sputter chamber SP1, the buffer chamber BU, the second sputter chamber SP2, Chamber ULL. As shown in Fig. 2 (a), by reactive sputtering when the transparent substrate 2 passes the vicinity of the first sputtering target 13 of the first sputtering chamber SP1, on the main surface of the transparent substrate 2 A phase shift film 3 including a single-layer film made of a chromium-based material having a predetermined film thickness is formed.

Instead of the first sputtering target 13 described above, the phase shift film 3 including a single layer film may be formed using the second sputtering target 14. In this case, a predetermined flow rate of sputter gas is introduced into the first sputter chamber SP1 from the fourth gas inlet GA22 on the downstream side of the second sputtering target 14, and a predetermined sputter power is supplied to the second sputtering target 14 . It is also possible to use a third sputtering target 15 of the second sputtering chamber SP2 in place of the first sputtering target 13 or the second sputtering target 14 of the first sputtering chamber SP1 to form a phase shift film 3) may be formed. In this case, a sputter gas of a predetermined flow rate is introduced into the second sputtering chamber SP2 from the sixth gas inlet GA32 on the downstream side of the third sputtering target 15, and a predetermined sputtering power is applied to the third sputtering target 15 .

A description will be given of a case where a phase shift film 3 made of a laminated film is formed (multiple film formation).

In this case, the transfer of the transparent substrate 2 in the direction of the arrow S and the transfer in the direction opposite to the arrow S are repeated, and during the transfer in the direction of the arrow S, the chromium system constituting part of the phase shift film 3 A first film forming method for depositing a phase shift film 3 by sequentially laminating a first sputtering target 13 and a second material layer on a transparent substrate 2 and a second sputtering target 13 during a single transport in the direction of an arrow S of the transparent substrate 2, The phase shift film 3 is formed by sequentially laminating chromium-based material layers constituting a part of the phase shift film 3 by using at least two of the target 14 and the third sputtering target 15, A film forming method, and a third film forming method in which a first film forming method and a second film forming method are combined. These film forming methods are appropriately selected depending on the number of layers of the phase shift film 3.

In the first film forming method, for example, the following procedure is followed.

The single-layer film formed as described above is set as the first layer of the chromium-based material layer constituting a part of the phase shift film 3, and then the transparent substrate 2 is removed from the take-out chamber ULL Back to the bring-in chamber LL, and the second-layer film formation of the chromium-based material layer constituting a part of the phase shift film 3 is performed again in the same manner as the film formation of the first-layer chromium-based material layer described above.

The same process is carried out in the case where the film formation of the third layer or later of the chromium-based material layer constituting part of the phase shift film 3 is carried out.

As shown in Fig. 2A, by the film forming process using the first film forming method, a two-layer or three-layer film composed of a chromium-based material having a predetermined film thickness on the main surface of the transparent substrate 2 A phase shift film 3 including a laminated film of a laminated structure or more is formed.

In the second film forming method, for example, the following procedure is followed.

First, the transparent substrate 2 is carried into the bring-in chamber LL of the sputtering apparatus 11.

Next, after the inside of the sputtering apparatus 11 is set to a predetermined degree of vacuum, a sputter gas at a predetermined flow rate is introduced into the first sputter chamber SP1 from the second gas inlet GA12 on the downstream side of the first sputtering target 13 A sputter gas having the same composition as the sputter gas introduced into the first sputter chamber SP1 is introduced into the second sputter chamber SP2 at a predetermined flow rate from the sixth gas inlet GA32 on the downstream side of the third sputtering target 15 The first sputtering target 13, and the third sputtering target 15, respectively. The application of the sputtering power and the introduction of the sputter gas continue until the transparent substrate 2 is transported to the discharge chamber ULL.

Thereafter, the transparent substrate 2 is conveyed in order from the carry-in chamber LL to the carry-out chamber ULL in the direction of arrow S at a predetermined conveying speed. When the transparent substrate 2 passes near the first sputtering target 13 of the first sputtering chamber SP1, the first layer of the chromium-based material layer of the predetermined film thickness on the main surface of the transparent substrate 2 is formed by reactive sputtering Is formed.

Thereafter, when the transparent substrate 2 passes through the vicinity of the third sputtering target 15 of the second sputtering chamber SP2, reactive sputtering is performed to form a chromium-based material layer having a predetermined film thickness on the first- The second layer is formed.

In the case of forming the phase shift film 3 made of a laminated film having a three-layer structure, the second sputtering target 14 of the first sputtering chamber SP1 is used in addition to the above sputtering target, and the second sputtering target The sputter gas is supplied at a predetermined flow rate from the fourth gas inlet GA22 on the downstream side of the first sputtering target 14 and a predetermined sputtering power is applied to the second sputtering target 14. [ In this case, the chromium-based material layer to be formed at the time of passing around the second sputtering target 14 becomes the second layer of the phase shift film 3 and the chromium-based material layer that is formed at the time of passing through the third sputtering target 15 The material layer becomes the third layer of the phase shift film 3.

As shown in Fig. 2A, by the film forming process using the second film forming method, a two-layer or three-layer film composed of a chromium-based material having a predetermined film thickness on the main surface of the transparent substrate 2 A phase shift film 3 including a laminated film of a laminated structure or more is formed.

In the third film forming method, any one of the first film forming method and the second film forming method described above may be performed first.

For example, first, a second film-forming method is performed to laminate a plurality of chromium-based material layers during the transportation of the transparent substrate 2 once, and thereafter, the first film-forming method is performed, It is possible to form the phase shift film 3 including the laminated film having the number of layers to be laminated.

As shown in Fig. 2A, by the film forming process using the third film forming method, a plurality of three or more layers made of a chromium-based material having a predetermined film thickness on the main surface of the transparent substrate 2 A phase shift film 3 including a lamination film having a layer of a phase shift film 3 is formed.

After the phase shift film 3 is formed on the main surface of the transparent substrate 2 in this manner, the transparent substrate 2 is taken out of the sputtering apparatus 11. Next,

3. VUV irradiation process

Next, as shown in Fig. 2 (b), the VUV irradiation process is performed on the outermost surface 3a of the phase shift film 3.

Here, the VUV irradiation process is a process of irradiating an uppermost surface 3a of the phase shift film 3 as an object to be irradiated (not shown) of a VUV irradiator (not shown) with a predetermined interval along the surface direction, (Not shown) while irradiating VUV with respect to the outermost surface 3a.

VUV used in the VUV irradiation treatment means that the wavelength is short in ultraviolet rays. It is known that VUV is mainly attenuated by absorption in the atmosphere, but can be prevented from being attenuated in vacuum. In the present invention, VUV means an ultraviolet ray having a wavelength of 10 nm to 200 nm, preferably a wavelength of 100 nm to 200 nm. Specifically, as the VUV, excimer light having a wavelength of 126 nm (argon), a wavelength of 146 nm (krypton) and a wavelength of 172 nm (xenon) can be used. In the present invention, a xenon excimer light having a wavelength of 172 nm Is preferably used. Further, the heat treatment may be carried out with or after the VUV irradiation. However, the reforming effect can be obtained even if the heating at a high temperature (for example, 200 DEG or more) is not performed.

The VUV irradiation conditions in the VUV irradiation process are preferably as follows.

The irradiation atmosphere is not particularly limited and can be an inert gas such as nitrogen or a vacuum, but a modification effect can be obtained even in the atmosphere. However, when the VUV irradiation process is performed in the atmosphere, it is preferable to reduce the distance between the irradiating portion (not shown) of the VUV irradiating device and the outermost surface of the phase shift film in consideration of the attenuation factor of VUV.

As the VUV irradiation energy, it is very important to make sufficient energy for the modification treatment of the phase shift film 3. For example, the uppermost surface 3a of the phase shift film 3 is set to 20 J / cm2 or more, preferably 30 J / cm2 or more, and more preferably 40 J / cm2 or more. Further, from the viewpoint of irradiation efficiency, it is preferably 60 J / cm 2 or less.

The VUV irradiation is performed by irradiating the surface of the phase shift film 3 with an irradiation section (not shown) provided with a light source (not shown) having an illuminance of 30 W / cm 2 to 50 W / (Irradiation at the same time on the outermost surface 3a by scanning is performed at a plurality of times in the same time). Specifically, when a light source (not shown) has an illuminance of 40 W / cm 2, a length of an irradiation area of 200 mm, a scanning speed of 10 mm / sec and a decay rate of 70% , The irradiation energy of 45 J / cm &lt; 2 &gt; can be given to the outermost surface 3a. Here, the decay rate refers to the ratio of the amount of residual after attenuation to the amount of irradiation from the irradiating unit (not shown).

It is preferable that the VUV irradiation is performed from the side of the outermost surface 3a of the phase shift film 3, not from the side of the transparent substrate 2, from the viewpoint of the decay rate of the transparent substrate 2 and the irradiation efficiency.

In the phase shift mask blank 1 of Embodiment 1 produced in this way, the phase shift film 3 is modified by the VUV irradiation process. The phase shift film 3 is formed with a composition gradient region R1 from its outermost surface 3a toward the film depth direction and a region R2 near the transparent substrate 2 is formed in the vicinity of the interface with the transparent substrate 2, And a bulk portion B is formed in an intermediate region excluding the region R1 and the region A2 near the transparent substrate.

The compositional gradient region R1 has a maximum value of the ratio of oxygen to chromium (hereinafter sometimes referred to as'O / Cr ') decreasing from the outermost surface 3a of the phase shift film 3 toward the film depth direction is 2 And the maximum value of the ratio of nitrogen to chromium (hereinafter sometimes referred to as 'N / Cr') which decreases from the outermost surface 3a toward the film depth direction is 0.45 or less. Also, O / Cr is a ratio of the number of oxygen atoms to the number of chromium atoms, and N / Cr is a ratio of the number of nitrogen atoms to the number of chromium atoms.

The compositional gradient region R1 exhibiting such characteristics is an upper surface region of the phase shift film 3 because it includes the outermost surface 3a of the phase shift film 3 and the film thickness thereof is, for example, 0.1 nm Or more and 10 nm or less, but it is not limited to this range.

The film density of the outermost surface 3a of the composition gradient region R1 is 2.0 g / cm3 or more. The film density of the outermost surface 3a of 2.0 g / cm 3 or more is preferable from the viewpoint of improving the tolerance and washing resistance, and more preferably 2.2 g / cm 3 or more.

The region R2 near the transparent substrate is a lower surface layer region of the phase shift film 3 that exhibits a characteristic in which O / Cr or N / Cr is inclined in the film depth direction, like the composition gradient region R1.

The bulk portion B is an inner region of the phase shift film 3 which exhibits a characteristic that the composition ratio of each element in the film depth direction is substantially uniform, unlike the composition gradient region R1 and the transparent substrate near region R2.

The content of each element constituting the phase shift film 3 is appropriately adjusted so as to be a desired optical property (transmittance to exposure light, phase difference).

When the material constituting the phase shift film 3 is made of CrON, the content of each element of the bulk part B can be measured by X-ray photoelectron spectroscopy (hereinafter, also referred to as 'XPS' ), Chromium is 35 atomic% or more and 65 atomic% or less, oxygen is 16 atomic% or more and 50 atomic% or less, and nitrogen is adjusted in the range of 6 atomic% or more and 30 atomic% or less. Preferably, chromium is 41 atomic% or more and 58 atomic% or less, oxygen is 21 atomic% or more and 43 atomic% or less, and nitrogen is 11 atomic% or more and 24 atomic% or less.

When the material constituting the phase shift film 3 is CrCON, the content of each element in the bulk portion B can be 35 atomic% or more and 60 atomic% or less in chromium and 15 At least 45 atomic%, nitrogen at least 5 atomic% and not more than 25 atomic%, and carbon at not less than 2 atomic% and not more than 15 atomic%. Preferably, chromium is 40 atomic% or more and 55 atomic% or less, oxygen is 20 atomic% or more and 40 atomic% or less, nitrogen is 10 atomic% or more and 20 atomic% or less, carbon is 3 atomic% or more and 10 atomic% to be.

In the bulk portion B, the composition ratio of each element in the film depth direction is substantially uniform as described above. Here, when the composition ratio of each element in the film depth direction is substantially uniform, the center value of the content of each element in the film depth direction of the phase shift film 3 obtained by the film formation conditions in the film formation step is used as a reference Means that the content of each element of the bulk portion B is contained in the range of the predetermined fluctuation range with respect to the central content thereof. For example, when the material constituting the phase shift film 3 is CrON, the variation range of chrome is ± 5.0 atomic% with respect to the central content of chromium, the variation range of oxygen is ± 6.5 atomic with respect to the central content of oxygen %, And the variation range of nitrogen is ± 4.5 atomic% with respect to the central content of nitrogen. Preferably, the variation range of chromium is 3.5 atomic%, the variation range of oxygen is +/- 5.5 atomic%, and the variation range of nitrogen is 3.5 atomic%. When the material constituting the phase shift film 3 is made of CrCON, the variation range of chromium is ± 5.0 atomic% with respect to the central content of chromium, the fluctuation range of oxygen is ± 6.5 atomic% with respect to the central content of oxygen, The variation range of nitrogen is ± 4.5 atomic% with respect to the central content of nitrogen, and the variation range of carbon is ± 4.0 atomic% with respect to the central content of carbon. Preferably, the fluctuation width of chromium is 3.5 atomic%, the fluctuation width of oxygen is ± 5.5 atomic%, the fluctuation width of nitrogen is ± 3.5 atomic%, and the fluctuation width of carbon is ± 3.0 atomic%.

The substantially uniform compositional ratio of the elements in the film depth direction in the bulk portion B can be adjusted by changing the composition of the sputtering material or the sputtering gas during the film forming process And the phase shift film 3 is formed without performing an operation of changing the supply amount.

The phase shift film 3 has the following characteristics by the VUV irradiation process.

(1) In the VUV irradiation step, the maximum value of O / Cr is changed to 2 or more and the maximum value of N / Cr is changed to 0.45 or less in the composition gradient region R1. By such a modification process, the sectional shape of the etched section of the edge portion of the phase shift film pattern 3 'obtained by patterning the phase shift film 3 becomes a sectional shape capable of sufficiently exhibiting the phase shift effect.

On the other hand, also in the conventional phase shift mask blank, a composition gradient region is formed from the outermost surface of the phase shift film toward the film depth direction, and this composition gradient region is also O / Cr N / Cr. &Lt; / RTI &gt; However, since the conventional phase shift film is not subjected to the VUV irradiation process, it is not subjected to modification by the VUV irradiation process. Therefore, the compositional gradient region of the conventional phase shift film does not satisfy the above-mentioned maximum value of O / Cr and the maximum value of N / Cr. Therefore, the edge of the phase shift film pattern obtained by patterning the phase shift film The cross sectional shape of the etching end face is inclined over the entire edge portion and tapered toward the transparent substrate so that the phase shift effect can not be sufficiently exhibited.

(2) The VUV irradiation step can be modified to change the film density of the outermost surface 3a to a higher value. The reason why the film density of the outermost surface 3a of the phase shift film 3 is increased is because the other atoms are supplied to the vicinity of the chromium atoms existing on the outermost surface 3a by the VUV irradiation process, . The other atom may be, for example, an oxygen atom. In this case, it is considered that the density of "CrO" on the outermost surface 3a is increased by filling the vacancy with oxygen atoms, resulting in an increase in the film density of the outermost surface 3a.

Concretely, the film density of the outermost surface 3a can be changed to 2.0 g / cm 3 or more by the VUV irradiation step. It is considered that the increase of the film density of the outermost surface 3a is considered to be one factor for improving the adhesion with the resist film 5 that can be used at the time of patterning the phase shift film 3. [

Assuming that the increase of the film density of the outermost surface 3a is derived from the increase of the density of CrO as described above, the assumption is that the edge of the etched section of the edge portion of the phase shift film pattern 3 ' It is believed that the cross-sectional shape is supported by the effect that the cross-sectional shape can sufficiently exhibit the phase shift effect. That is, when oxygen (O) is supplied to the outermost surface 3a, the content of nitrogen (N) that accelerates the etching rate relatively decreases. Therefore, isotropic etching (wet etching The etch rate of the portion to be etched (in the vicinity of the outermost surface 3a) near the resist film 5 in the etched end face of the edge portion becomes slow. This allows the portion to be etched in the vicinity of the resist film 5 to be maintained until the main surface of the transparent substrate 2 is exposed by etching and then reaches the lower portion of the edge portion, This is because the occurrence of so-called erosion phenomenon due to the etching solution is considered to be less at the portion to be etched in the vicinity of the etched surface.

The film density of the outermost surface 3a can be measured by, for example, X-ray reflectance analysis (XRR). The values of the film densities of the outermost surface 3a in the examples and the comparative examples were measured by dividing the film density of the outermost surface 3a in the film thickness direction of the phase shift film 3 into a numerical value FitR indicating the validity of the fitting 0.025 or less.

(3) In the VUV irradiation step, the composition ratio of each element in the film depth direction of the bulk part B is not changed. As a result, the composition ratio of each element in the film depth direction of the bulk portion B remains substantially uniform as in the case where the VUV irradiation step is not performed. In other words, even when the VUV irradiation step is performed, there is no case where a large change is given to the composition ratio of each element in the film depth direction of the bulk portion B of the phase shift film 3 before the VUV irradiation step, ) Can maintain desired optical properties (transmittance, phase difference).

(4) The VUV irradiation step increases the O / Cr reduction ratio in the composition gradient region R1 after the VUV irradiation treatment before the VUV irradiation treatment and increases the N / Cr reduction ratio after the VUV irradiation treatment before the VUV irradiation treatment It is possible to perform the modification. That is, in the isotropic etching (wet etching) at the time of patterning with respect to the phase shift film 3 made of the chromium-based material, the content of oxygen which does not significantly change the etching rate in the composition gradient region R1 is compared with that before the VUV irradiation treatment And changes with a large reduction rate. On the other hand, the content of nitrogen which accelerates the etching rate changes at a small reduction rate as compared with that before the VUV irradiation treatment. As a result, when the etching proceeds in the depth direction of the film, the etching rate is gently increased in the composition gradient region R1 after the VUV irradiation process as compared with that before the VUV irradiation process. Due to the relaxation property of the increasing tendency of the etching rate in the composition gradient region R1, when etching proceeds from the composition gradient region R1 to the bulk portion B and proceeds, the large gap with the etching rate in the bulk portion B is eliminated And the etching rate is continuously changed, so that the etched end face of the edge portion can be formed as a continuous surface.

(5) In the region R2 near the transparent substrate, as described above, O / Cr or N / Cr is inclined in the film depth direction unlike the bulk portion B, but in the VUV irradiation process performed from the uppermost surface 3a side , And the inclined composition of O / Cr or N / Cr in the region R2 near the transparent substrate is not affected by the VUV irradiation process.

(6) As described above, the VUV irradiation step can hardly change the transmittance of the phase shift film 3 at the time of film formation, and the edge of the phase shift film pattern 3 'obtained by patterning the phase shift film 3 Sectional shape of the portion to be etched can be formed into a sectional shape that can sufficiently exhibit the phase shift effect completely different from the case where the VUV irradiation step is not performed. Further, in the VUV irradiation step, most of the phase shift film 3 at the time of film formation does not change the reflectance. This indicates a possibility that the CD deviation of the phase shift film pattern 3 'can be controlled in a very narrow range, and also in this respect, the VUV irradiation process is considered effective.

The phase shift mask blank 1 of Embodiment 1 is manufactured by such a preparation step, a phase shift film forming step, and a VUV irradiation step.

According to the phase shift mask blank 1 of Embodiment 1 thus manufactured, the phase shift film 3 containing chromium, oxygen, and nitrogen is formed on the transparent substrate 2. In the phase shift film 3, a composition gradient region R1 is formed from the outermost surface 3a toward the film depth direction. In the composition gradient region R1, an O / The maximum value of Cr is 2 or more and the maximum value of N / Cr decreasing from the outermost surface 3a toward the film depth direction is 0.45 or less. Therefore, in the phase shift mask blank 1, it is possible to pattern the phase shift film with a cross-sectional shape such that the phase shift film 3 can sufficiently exhibit the phase shift effect by wet etching. The phase shift mask blank 1 can have a cross sectional shape of an etched section of the edge portion of the phase shift film pattern obtained by patterning the phase shift film 3 so as to exhibit a sufficient phase shift effect The resolution can be improved and a master disc for manufacturing a phase shift mask having a phase shift film pattern having good CD characteristics can be obtained.

According to the manufacturing method of the phase shift mask blank 1 of the first embodiment, the film forming step of forming the phase shift film 3 containing chromium, oxygen and nitrogen on the transparent substrate 2 by the sputtering method, And a VUV irradiation processing step of performing VUV irradiation processing on the outermost surface 3a of the phase shift film 3 formed. This VUV irradiation treatment step is a step of irradiating the phase shift film 3 with an O / N ratio decreasing from the outermost surface 3a toward the film depth direction in the composition gradient region R1 formed from the outermost surface 3a of the phase shift film 3 toward the film depth direction. The maximum value of Cr is changed to 2 or more and the maximum value of N / Cr decreasing from the outermost surface 3a toward the film depth direction is changed to 0.45 or less. As a result, the phase shift mask blank 1 capable of patterning the phase shift film 3 in a cross-sectional shape capable of sufficiently exhibiting the phase shift effect can be manufactured by wet etching. The cross sectional shape of the etched section of the edge portion of the phase shift film pattern can be made to have a sectional shape capable of sufficiently exhibiting the phase shift effect so that the resolution can be improved and patterning to the phase shift film pattern having good CD characteristics can be performed The phase shift mask blank 1 can be manufactured.

In Embodiment 1, the composition gradient region R1 is formed by, for example, the VUV irradiation process with respect to the outermost surface 3a of the phase shift film 3 in the post-deposition state, but the present invention is not limited thereto. The composition gradient region R1 may be formed by any process other than the VUV irradiation process as long as the process can be modified to have the above-described characteristics.

The phase shift film 3 of the transparent substrate 2 formed by the phase shift film forming step in the first embodiment may be subjected to a VUV irradiation step as a subsequent step immediately after the film formation, The VUV irradiating step may be performed after being stored in a predetermined case for a predetermined period. The storage may be, for example, a period of about one month, but is not limited thereto. When the VUV treatment process is performed before storage, for example, even after storage for about one month, irrespective of the presence or absence of cleaning (excluding sulfuric acid cleaning), the phase shift film pattern formed by wet etching using the resist film pattern as a mask The sectional shape becomes better than the sectional shape in which the VUV processing is not performed. When performing the VUV irradiation process after storage, it is not necessary to perform predetermined film cleaning. There is a possibility that the exposed portion such as the outermost surface 3a of the phase shift film 3 is slightly contaminated during storage, but even if it is contaminated, the modification effect by the VUV irradiation process is not affected. Preferably, the VUV irradiation step is performed immediately before the formation of the resist film. When the surface of the phase shift film 3 is washed with sulfuric acid and then the resist film pattern is formed on the phase shift film 3 in the process of manufacturing the photomask blank, However, when the VUV irradiation is performed after the cleaning of the phase shift film 3 with sulfuric acid and before the formation of the resist film, the cross-sectional shape of the phase shift film pattern is difficult to be tapered and may be vertical. That is, when the surface of the phase shift film 3 is washed with sulfuric acid, the adhesion between the resist film and the film surface of the phase shift film 3 is markedly decreased. Therefore, the cross-sectional shape after the wet etching process using the resist film pattern as a mask The resolution of the phase shift film can not be effectively utilized because it becomes a very large tapered shape. By performing the VUV irradiation step even after the sulfuric acid cleaning of the phase shift film 3, the cross-sectional shape of the phase shift film pattern can be remarkably improved. In addition, there is a possibility that the cross-sectional shape of the phase shift film pattern can be verticalized by strengthening the rinsing after the sulfuric acid cleaning on the phase shift film 3 and reducing the sulfur component to the utmost and conducting the VUV irradiation step.

The phase shift mask blank 1 of Embodiment 1 in which the VUV irradiation process is performed may be used as a raw disk for manufacturing in the method of manufacturing a phase shift mask immediately after the VUV irradiation process. Even if the phase shift mask blank 1 is stored in a predetermined case for a predetermined period, the modification effect by the VUV irradiation process on the phase shift film 3 is maintained. Thus, after the storage, it can be used as a preparation substrate in the production method of the phase shift mask. Since the phase shift mask blank 1 can be stored in this way, a certain amount of the phase shift mask blank 1 can be reserved and used at the time of shipment and production of a phase shift mask, and the handling property can be improved . The storage may be, for example, a period of about two weeks, but is not limited thereto.

In Embodiment 1, the case of using the in-line sputtering apparatus 11 having the above-described structure is described in the film forming step, but an in-line sputtering apparatus having a different structure may be used. As an in-line sputtering apparatus of another constitution, for example, a fourth sputtering target (not shown) including chromium for forming the phase shift film 3 is disposed in the second sputtering chamber SP2 on the side of the take-out chamber ULL , A seventh gas inlet (not shown) is disposed at a position on the upstream side of the fourth sputtering target in the transport direction indicated by arrow S of the transparent substrate 2 in the vicinity of the fourth sputtering target, And an eighth gas inlet (not shown) is disposed at the downstream side of the target. In this manner, also in the case of disposing the fourth sputtering target (not shown), as in the arrangement relationship of the other sputtering target and the gas introduction ports arranged on both sides in the carrying direction thereof, the fourth sputtering target (not shown) The interval of the eighth gas inlet (not shown) is preferably set to be wider than the interval between the fourth sputtering target (not shown) and the seventh gas inlet (not shown) on the upstream side.

In the phase shift film forming step described above, the film formation is performed by supplying the sputter gas from the gas introduction port on the downstream side of the sputtering target. However, as another method of supplying the sputtering gas, The film formation may be performed by supplying a sputter gas. In any case, the phase-shift film 3 formed after the VUV irradiation process described above is subjected to the above-described VUV irradiation process, the cross-sectional shape of the etched section of the edge portion of the phase shift film pattern 3 ' (Refer to Comparative Examples 1 and 2, which will be described later) of the edge section of the conventional phase shift film pattern in which the VUV irradiation step is not performed. Particularly, when the sputter gas is supplied from the gas inlet on the downstream side as in the above-described film forming step, the sectional shape of the etched section of the edge portion of the phase shift film pattern 3 ' It is also possible to have a vertical cross-sectional shape.

Embodiment 2

In Embodiment 2, a method of manufacturing a phase shift mask for manufacturing a display device (transparent substrate / phase shift film pattern) will be described.

4 (a) to 4 (e) are cross-sectional views showing respective steps of a method of manufacturing a phase shift mask according to Embodiment 2 of the present invention, in which the same components as in Figs. 1 to 3 are denoted by the same reference numerals Omit duplicate description.

The phase shift mask 30 of the second embodiment has a structure in which the phase shift film pattern 3 'is formed on the transparent substrate 2.

In the method of manufacturing the phase shift mask according to the second embodiment, the phase shift mask blank 1 (see FIG. 1) described in the first embodiment or the manufacturing method of the phase shift mask blank described in the first embodiment A resist film pattern forming step for forming a resist film pattern 5 'on the phase shift film 3 of the phase shift mask blank 1 (see FIG. 2 (b)) obtained by the above process is performed.

Specifically, in this resist film pattern forming step, first, as shown in Fig. 4A, a phase shift mask blank (in which a phase shift film 3 made of a chromium-based material is formed on a transparent substrate 2 1) is prepared. Thereafter, as shown in Fig. 4 (b), a resist film 5 is formed on the phase shift film 3. Thereafter, as shown in FIG. 4C, a pattern of a predetermined size is drawn on the resist film 5, the resist film 5 is developed with a predetermined developer, and the resist film pattern 5 ').

As a pattern to be drawn on the resist film 5, a line-and-space pattern or a hole pattern can be given.

Next, as shown in FIG. 4D, the phase shift film 3 is wet-etched using the resist film pattern 5 'as a mask to form a phase shift film 3' A film pattern forming step is performed.

The etching solution for wet etching the phase shift film 3 is not particularly limited as long as it can selectively etch the phase shift film 3 made of a chromium-based material. Specifically, an etchant containing ceric ammonium nitrate and perchloric acid can be mentioned.

After the formation of the phase shift film pattern 3 ', the resist film pattern 5' is peeled as shown in FIG. 4 (e).

The phase shift mask 30 of the second embodiment is manufactured by such a resist film pattern forming step and a phase shift film pattern forming step.

Like the phase shift film 3 of the phase shift mask blank 1, the phase shift film pattern 3 'has a property of changing the phase of exposure light. Due to this property, a predetermined retardation occurs between the exposure light transmitted through the phase shift film pattern 3 'and the exposure light transmitted through only the transparent substrate 2. When the exposure light is composite light containing light in a wavelength range of 300 nm to 500 nm, the phase shift film pattern 3 'is formed so as to generate a predetermined retardation with respect to the light of the representative wavelength. For example, when the exposure light is composite light including i-line, h-line and g-line, the phase shift film pattern 3 'has a phase difference of 180 ° with respect to any one of the i-line, h- . In order to exhibit the phase shift effect, for example, the phase difference of the phase shift film pattern 3 'in the i-line is set in the range of 180 ° ± 10 °, and preferably set to approximately 180 ° . The transmittance of the phase shift film pattern 3 'in i-line is preferably set to a range of 1% to 20%, particularly preferably 3% to 15%.

The composition ratios of the respective elements of the phase shift film pattern 3 'are set such that the composition gradient region and phase shift film pattern 3' formed from the outermost surface of the phase shift film pattern 3 ' ) In the vicinity of the interface with the transparent substrate. However, in the composition gradient region and the vicinity of the transparent substrate formed from the outermost surface of the phase shift film pattern 3 'toward the film depth direction, a region having an inclined composition is formed, and the composition of such portions is not uniform.

The cross-sectional shape of the etched section of the edge portion of the phase shift film pattern 3 'is such that the top surface 3a of the phase shift film 3 is subjected to the above-described VUV irradiation processing so that the composition gradient region R1 is modified So that it is difficult to form a tapered shape.

Here, the cross-sectional angle? (Refer to FIG. 14 described later) of the etched section of the edge portion of the phase shift film pattern 3 'is set to 90 degrees or as close as possible to 90 degrees Angle.

However, the phase shift effect can be sufficiently exerted even when the cross-sectional angle? Is not 90 ° or an angle close to 90 °. For example, even if the edge portion of the edge portion of the phase shift film pattern 3 'is slightly etched away from the portion to be etched of the edge portion close to the transparent substrate 2, the resist film pattern 5 , The phase shift effect can be sufficiently exerted if a large part of the etched section of the edge portion of the phase shift film pattern 3 'is at an angle of 90 ° or close to 90 °.

The thus manufactured phase shift mask 30 for manufacturing a display device is used for projection exposure of equal exposure to fully exhibit a phase shift effect. In particular, as the exposure environment, the numerical aperture (NA) is preferably 0.06 to 0.15, more preferably 0.08 to 0.10, and the coherence factor (sigma) is preferably 0.5 to 1.0.

According to the method of manufacturing the phase shift mask of the second embodiment, the phase shift mask blank 1 described in the first embodiment or the phase shift mask blank 1 obtained by the method of manufacturing the phase shift mask blank described in the first embodiment The phase shift mask 30 is fabricated. Thus, the phase shift mask 30 having the phase shift film pattern 3 'capable of sufficiently exhibiting the phase shift effect can be manufactured. Since the phase shift film pattern 3 'can sufficiently exhibit the phase shift effect, it is possible to manufacture the phase shift mask 30 having the phase shift film pattern 3' having good CD characteristics by improving the resolution. This phase shift mask 30 can cope with miniaturization of the line-and-space pattern and the contact hole.

In Embodiment 2, the phase shift mask blank 1 having the structure of the transparent substrate / phase shift film is used as the original plate for manufacturing the phase shift mask 30, but the present invention is not limited thereto. For example, a phase shift mask blank having a structure of a transparent substrate / phase shift film / resist film (see FIG. 4 (b)) may be used as a disk for manufacturing the phase shift mask 30.

In the second embodiment, the phase shift film 3 of the phase shift mask blank 1 may be subjected to film cleaning as required before the resist film pattern forming process. For the membrane cleaning, a known cleaning method can be used. However, it is preferable to use a cleaning method other than the cleaning method using a cleaning liquid (for example, sulfuric acid and water) containing a sulfur (S) component. In the film cleaning using a cleaning liquid containing a sulfur (S) component, the sulfur (S) component remains on the phase shift film 3. Therefore, when the phase shift film 3 is patterned by the remaining sulfur (S) component to obtain the phase shift film pattern 3 ', the sectional shape of the etched section of the edge portion becomes tapered Because it is easy.

Embodiment 3

In Embodiment 3, a phase shift mask blank (transparent substrate / light shielding film pattern / phase shift film) for manufacturing a display device and a manufacturing method thereof will be described.

FIG. 5 is a cross-sectional view showing the structure of a phase shift mask blank according to Embodiment 3 of the present invention, and FIGS. 6 (a) to 6 (g) And the same constituent elements as those in Figs. 1 to 4 are denoted by the same reference numerals, and redundant description is omitted.

5, the phase shift mask blank 10 of the third embodiment includes a transparent substrate 2, a light shielding film pattern 4 'formed on the main surface of the transparent substrate 2, And a phase shift film 3 formed on the main surface of the transparent substrate 2 and the phase shift film 4 '.

The method of manufacturing the phase shift mask blank 10 of the third embodiment thus configured is a method of manufacturing a phase shift mask blank 10 in which a light shielding film 4 is formed by sputtering on a main surface of a transparent substrate 2, A light-shielding film pattern forming step of forming a light-shielding film pattern 4 'by patterning the light-shielding film 4 and a chromium film (not shown) on the light-shielding film pattern 4' A phase shift film forming step of forming a phase shift film 3 containing oxygen and nitrogen, and a VUV irradiation step of performing VUV irradiation processing on the outermost surface 3a of the formed phase shift film 3 .

Hereinafter, each step will be described in detail.

1. Preparation process

First, the transparent substrate 2 is prepared.

This preparation step is performed in the same manner as the preparation step in Embodiment 1. [

2. Light-shielding film forming process

Next, as shown in Fig. 6A, the light-shielding film 4 is formed on the main surface of the transparent substrate 2 by sputtering.

Specifically, in this light-shielding film forming step, a film forming step for forming a light-shielding film 4 composed of a predetermined material by applying sputtering power in a sputter gas atmosphere is performed.

The material and film thickness of the light-shielding film 4 are adjusted such that the optical density of the light-shielding film 4 with respect to the exposure light is 2.8 or more, and preferably 3.0 or more, in total with the phase shift film 3.

The material constituting the light-shielding film 4 is not particularly limited, but is preferably a material used for the mask blank. Examples of the material used for the mask blank include a material containing chromium, a material containing tantalum, and a material containing metal and silicon (Si) (metal silicide material). The material containing chromium is not particularly limited as long as it contains chromium (Cr), and examples thereof include chromium (Cr), oxides of chromium, nitrides of chromium, carbides of chromium, and fluorides of chromium. The material containing tantalum is not particularly limited as long as it contains tantalum (Ta), and examples thereof include tantalum (Ta), tantalum oxide, and tantalum nitride. As the metal silicide material, for example, a nitride of a metal suicide, an oxide of a metal suicide, an oxynitride of a metal suicide, a carbonitride of a metal suicide, an oxycarbide of a metal suicide, and an oxycarbonitride of a metal suicide. Examples of the metal include transition metals such as molybdenum (Mo), tantalum (Ta), tungsten (W), and titanium (Ti). The composition of the metal and silicon is adjusted in view of the optical characteristics of the light-shielding film 4. The ratio of metal to silicon is suitably selected according to the kind of metal and optical characteristics required for the light-shielding film, and metal: silicon is preferably 1: 1 or more and 1: 9 or less.

The material constituting the light-shielding film 4 may contain other elements such as oxygen (O), nitrogen (N) and carbon (C), if necessary.

The light-shielding film 4 may be either a single layer or a plurality of layers. In the case where the light shielding film 4 is composed of a plurality of layers, for example, there is a case of a laminated structure composed of a light shielding layer formed on the side of the phase shift film 3 and an antireflection layer formed on the light shielding layer. The light-shielding layer may be either a single layer or a plurality of layers. Examples of the light-shielding layer include a chromium nitride film (CrN), a chromium carbide film (CrC), and a chromium carbide nitride film (CrCN). The antireflection layer may be provided on the surface of the light-shielding film for the purpose of reducing the reflectance of the exposure light, and the antireflection layer may be composed of one layer or a plurality of layers. As the antireflection layer, for example, a chromium oxynitride film (CrON) can be mentioned.

For forming the light-shielding film 4, a sputtering apparatus such as a cluster-type sputtering apparatus or an in-line sputtering apparatus is used.

The light-shielding film 4 can be formed by, for example, a sputtering target and a sputter gas atmosphere as described below.

As the sputtering target used for forming the light-shielding film 4 made of a material containing chromium, one containing chromium (Cr) or a chromium compound is selected. Specifically, examples thereof include chromium (Cr), a nitride of chromium, an oxide of chromium, a carbide of chromium, an oxynitride of chromium, a carbonitride of chromium, an oxide carbide of chromium, and an oxide carbonitride of chromium.

Sputter gas atmosphere at the time of film formation of the light-shielding film 4 made of a material containing chromium, nitrogen (N ₂₎ gas, nitrogen monoxide (NO) gas and nitrogen dioxide (NO ₂₎ gas, nitrous oxide (N ₂ O) An active gas including at least one selected from the group consisting of carbon monoxide (CO) gas, carbon dioxide (CO ₂ ) gas, oxygen (O ₂ ) gas, hydrocarbon gas and fluorine gas, And an inert gas containing at least one selected from the group consisting of a gas including argon, neon (Ne) gas, argon (Ar) gas, krypton (Kr) gas and xenon (Xe) gas. , For example, methane gas, butane gas, propane gas, and styrene gas.

The combination of the above-described material for forming the sputtering target and the gas type of the sputter gas atmosphere and the mixing ratio of the active gas and the inert gas in the sputter gas atmosphere are appropriately determined according to the type and composition of the chromium-based material constituting the light- do.

As the sputtering target used for forming the light-shielding film 4 made of a material containing tantalum, one containing tantalum (Ta) or tantalum compound is selected. Specifically, tantalum (Ta), an oxide of tantalum, and a nitride of tantalum can be mentioned.

Sputter gas atmosphere is nitrogen (N ₂₎ gas, nitrogen monoxide (NO) gas and nitrogen dioxide (NO ₂₎ gas, nitrous oxide (N ₂ O) at the time of film formation of the light-shielding film 4 made of a material containing tantalum An active gas including at least one selected from the group consisting of a gas, a carbon monoxide (CO) gas, a carbon dioxide (CO ₂ ) gas and an oxygen (O ₂ ) And an inert gas containing at least one selected from the group consisting of argon (Ar) gas, krypton (Kr) gas and xenon (Xe) gas.

The combination of the above-described material for forming the sputtering target and the gas type of the sputter gas atmosphere or the mixing ratio of the active gas and the inert gas in the sputter gas atmosphere may be changed depending on the type and composition of the tantalum- Is determined appropriately.

As the sputtering target used for forming the light-shielding film 4 made of a metal silicide material, a metal and a material containing silicon (Si) are selected. Specifically, there can be mentioned metal silicide, nitride of metal suicide, oxide of metal suicide, carbide of metal suicide, oxynitride of metal suicide, carbonitride of metal suicide, oxycarbide of metal suicide, and oxycarbonitride of metal suicide have.

The atmosphere of the sputter gas at the time of forming the light-shielding film 4 made of the metal silicide material may be at least one selected from the group consisting of nitrogen (N ₂ ) gas, nitrogen monoxide NO gas, nitrogen dioxide (NO ₂ ) gas, nitrous oxide (N ₂ O) An active gas containing at least one selected from the group consisting of carbon monoxide (CO) gas, carbon dioxide (CO ₂ ) gas and oxygen (O ₂ ) gas, and an active gas including at least one selected from the group consisting of He gas, Ne gas, And an inert gas containing at least one kind selected from the group consisting of Ar gas, krypton (Kr) gas and xenon (Xe) gas.

The combination of the above-described material for forming the sputtering target and the gas type of the sputter gas atmosphere and the mixing ratio of the active gas and the inert gas in the sputter gas atmosphere are appropriately determined according to the type and composition of the metal silicide material constituting the light- do.

The light-shielding film forming process can be performed, for example, by using the sputtering apparatus 11 shown in Fig.

Here, a case where the light-shielding film 4 made of a material containing chromium is formed will be described as an example.

First, for example, in the case of forming the light-shielding film 4 having a laminated structure composed of the light-shielding layer and the antireflection layer, the first sputtering chamber SP1 is formed with the first sputtering (including chromium) for forming the light- A target 13 is disposed and a third sputtering target 15 containing chromium for forming the antireflection layer of the light-shielding film 4 is disposed in the second sputter chamber SP2.

Thereafter, in order to form the light-shielding film 4, the transparent substrate 2 mounted on a tray (not shown) is carried into the loading chamber LL.

Thereafter, a predetermined flow rate of sputter gas is introduced from the second gas inlet port GA12 while the inside of the sputtering apparatus 11 is set to a predetermined degree of vacuum, and a predetermined sputtering power is applied to the first sputtering target 13 do. A predetermined flow rate of sputter gas is introduced from the sixth gas inlet GA32, and a predetermined sputtering power is applied to the third sputtering target 15. The application of the sputtering power and the introduction of the sputter gas continue until the transparent substrate 2 is transported to the discharge chamber ULL.

Thereafter, the transparent substrate 2 mounted on a tray (not shown) is transported at a predetermined transporting speed in the direction of the arrow S to the transfer chamber LL, the first sputter chamber SP1, the buffer chamber BU, the second sputter chamber SP2, Chamber ULL. The transparent substrate 2 is subjected to reactive sputtering when passing through the vicinity of the first sputtering target 13 of the first sputtering chamber SP1 to form a light shielding layer composed of a chromium- A layer is deposited. Further, when the transparent substrate 2 passes near the third sputtering target 15 of the second sputtering chamber SP2, an anti-reflection layer composed of a chromium-based material having a predetermined film thickness is formed on the light-shielding layer by reactive sputtering .

A light shielding film 4 of a laminated structure composed of a light shielding layer and an antireflection layer is formed on the main surface of the transparent substrate 2 and then the transparent substrate 2 is taken out to the outside of the sputtering apparatus 11. [

3. Light-shielding film pattern formation process

Next, the light-shielding film pattern forming step for forming the light-shielding film pattern 4 'on the main surface of the transparent substrate 2 is performed.

Specifically, in this light-shielding film pattern forming step, first, a resist film 5 is formed on the light-shielding film 4 as shown in Fig. 6 (b). 6C, a pattern of a predetermined size is drawn on the resist film 5, and then the resist film 5 is developed with a predetermined developing solution to form a resist film pattern 5 ').

As a pattern to be drawn on the resist film 5, a line-and-space pattern or a hole pattern can be given.

6 (d), the light-shielding film pattern forming process for forming the light-shielding film pattern 4 'is performed by wet-etching the light-shielding film 4 using the resist film pattern 5' as a mask .

When the light-shielding film 4 is made of a chromium-based material, the etching solution for wet etching the light-shielding film 4 is not particularly limited as long as it can selectively etch the light-shielding film 4. Specifically, an etchant containing ceric ammonium nitrate and perchloric acid can be mentioned.

When the light-shielding film 4 is made of a metal silicide material, the etching solution for wet etching the light-shielding film 4 is not particularly limited as long as it can selectively etch the light-shielding film 4. For example, an etching solution containing at least one fluorine compound selected from hydrofluoric acid, hydrofluoric acid and hydrogen fluoride and at least one oxidizing agent selected from hydrogen peroxide, nitric acid and sulfuric acid can be mentioned. Specifically, an etching solution obtained by diluting a mixed solution of ammonium hydrogen fluoride and hydrogen peroxide with pure water can be mentioned.

When the light-shielding film 4 is made of a tantalum-based material, the etching solution for wet etching the light-shielding film 4 is not particularly limited as long as it can selectively etch the light-shielding film 4. Specifically, an etching solution containing sodium hydroxide and hydrogen peroxide can be mentioned.

After the light-shielding film pattern 4 'is formed, the resist film pattern 5' is peeled as shown in FIG. 6 (e).

4. Phase shift film forming process

6 (f), a phase shift film forming step for forming the phase shift film 3 on the light-shielding film pattern 4 'on the transparent substrate 2 is performed.

This phase shift film forming step is performed in the same manner as the phase shift film forming step in the first embodiment.

5. VUV irradiation process

Next, as shown in FIG. 6 (g), the VUV irradiation process is performed on the outermost surface 3a of the phase shift film 3.

This VUV irradiation step is performed in the same manner as the VUV irradiation step in the first embodiment.

The phase shift film 3 subjected to the VUV irradiation process is modified by the VUV irradiation process so as to have the same characteristics as those of the phase shift film 3 in the phase shift mask blank 1 of Embodiment 1 .

The phase shift mask blank 10 of the third embodiment is manufactured by such a preparation step, a light-shielding film forming step, a light-shielding film pattern forming step, a phase shift film forming step, and a VUV irradiation step.

According to the phase shift mask blank 10 of Embodiment 3 thus produced, the light-shielding film pattern 4 'is interposed on the main surface of the transparent substrate 2 or directly on the main surface of the transparent substrate 2, A phase shift film 3 containing chromium, oxygen and nitrogen is formed. In the composition gradient region R1 of the phase shift film 3, the maximum value of O / Cr decreasing from the outermost surface 3a toward the film depth direction is 2 or more, and also the decrease from the outermost surface 3a toward the film depth direction The maximum value of N / Cr is 0.45 or less. Thus, the phase shift mask blank 10 can be patterned into a cross-sectional shape in which the phase shift film 3 can sufficiently exhibit a phase shift effect by wet etching. The phase shift mask blank 10 has a cross sectional shape of an etched section of the edge portion of the phase shift film pattern 3 'obtained by patterning the phase shift film 3, The resolution can be improved and a master disc for manufacturing a phase shift mask having a phase shift film pattern having good CD characteristics can be obtained.

According to the manufacturing method of the phase shift mask blank of Embodiment 3, the light-shielding film pattern 4 'is interposed on the main surface of the transparent substrate 2 or directly on the main surface of the transparent substrate 2 with chromium and oxygen And a VUV radiation treatment process for performing a VUV irradiation process on the outermost surface 3a of the phase shift film 3 formed by the film formation process . In this VUV irradiation process step, the maximum value of O / Cr decreasing from the outermost surface 3a toward the film depth direction is changed to 2 or more in the composition gradient region R1, and the depth direction of the film from the outermost surface 3a Cr is decreased to 0.45 or less. As a result, the phase shift mask blank 10 capable of patterning the phase shift film in a cross-sectional shape capable of sufficiently exhibiting the phase shift effect can be manufactured by wet etching. In addition, since the sectional shape of the etched section of the edge portion of the phase shift film pattern 3 'can be a sectional shape capable of sufficiently exhibiting the phase shift effect, the resolution can be improved and the phase shift film having good CD characteristics A phase shift mask blank 10 capable of patterning into a pattern can be manufactured.

Embodiment 4

In Embodiment 4, a manufacturing method of a phase shift mask for manufacturing a display device (transparent substrate / light-shielding film pattern / phase shift film pattern) will be described.

7A to 7E are cross-sectional views showing respective steps of a method of manufacturing a phase shift mask according to Embodiment 4 of the present invention using the phase shift mask blank shown in Fig. 5, and Fig. 1 The same components as those in FIG. 6 are denoted by the same reference numerals, and redundant description will be omitted.

The phase shift mask 31 manufactured by the method of manufacturing the phase shift mask blank of Embodiment 4 is formed by sandwiching the light shielding film pattern 4 'on the main surface of the transparent substrate 2, And a phase shift film pattern 3 'containing chromium, oxygen and nitrogen is formed directly on the gate insulating film 3'.

In the method of manufacturing the phase shift mask of the fourth embodiment thus configured, first, the phase shift mask blank 10 (see FIG. 5) described in the third embodiment or the manufacturing method of the phase shift mask blank described in the third embodiment A resist film pattern forming step of forming a resist film pattern 5 'on the phase shift film 3 of the phase shift mask blank 10 (see FIG. 6 (g)) obtained by the above process is performed.

7A, a light-shielding film pattern 4 'is interposed on the main surface of the transparent substrate 2, or the light-shielding film pattern 4' is formed on the transparent substrate 2 ), A phase shift mask blank 10 in which a phase shift film 3 containing chromium and oxygen and nitrogen is formed is prepared. Thereafter, as shown in Fig. 7 (b), a resist film 5 is formed on the phase shift film 3. Thereafter, as shown in FIG. 7C, a pattern of a predetermined size is drawn on the resist film 5, and then the resist film 5 is developed with a predetermined developer to form a resist film pattern 5 ').

As a pattern to be drawn on the resist film 5, a line-and-space pattern or a hole pattern can be given.

7 (d), the phase shift film 3 is wet-etched using the resist film pattern 5 'as a mask, and the phase shift film 3' A film pattern forming step is performed.

The etching solution for wet etching the phase shift film 3 is not particularly limited as long as it can selectively etch the phase shift film 3 made of a chromium-based material. Specifically, an etchant containing ceric ammonium nitrate and perchloric acid can be mentioned.

The obtained phase shift film pattern 3 'has the property of changing the phase of the exposure light similarly to the phase shift film pattern 3' in Embodiment Mode 2, and the cross-sectional shape of the etched cross- Since the outermost surface 3a of the shift film 3 is subjected to the above-described VUV irradiation treatment and the composition gradient region R1 is modified, it is difficult to form a taper shape.

After forming the phase shift film pattern 3 ', the resist film pattern 5' is peeled off as shown in FIG. 7 (e).

The phase shift mask 31 of the fourth embodiment is manufactured by such a resist film pattern forming step and a phase shift film pattern forming step.

The thus manufactured phase shift mask 31 for use in manufacturing a display device is used for projection exposure of equal exposure, and sufficiently exhibits a phase shift effect. In particular, as the exposure environment, the numerical aperture (NA) is preferably 0.06 to 0.15, more preferably 0.08 to 0.10, and the coherence factor (sigma) is preferably 0.5 to 1.0.

According to the method of manufacturing the phase shift mask of the fourth embodiment, the phase shift mask blank 10 described in the third embodiment or the phase shift mask blank 10 obtained by the method of manufacturing the phase shift mask blank described in the third embodiment The phase shift mask 31 is manufactured. This makes it possible to manufacture the phase shift mask 31 having the phase shift film pattern 3 'capable of sufficiently exhibiting the phase shift effect. Since the phase shift film pattern 3 'can sufficiently exhibit the phase shift effect, the phase shift mask 31 having the phase shift film pattern 3' having good CD characteristics can be manufactured by improving the resolution. This phase shift mask 31 can cope with the miniaturization of the line-and-space pattern and the contact hole.

In the fourth embodiment, the phase shift mask blank 10 having the structure of the transparent substrate / the light-shielding film pattern / phase shift film is used as the original plate for manufacturing the phase shift mask 31, but the present invention is not limited thereto. For example, the phase shift mask blank having the structure of the transparent substrate / light-shielding film pattern / phase shift film / resist film (see FIG. 7 (b)) may be used as a substrate for producing the phase shift mask 31.

In the fourth embodiment, as in the second embodiment, the phase shift film 3 of the phase shift mask blank 10 may be subjected to film cleaning as necessary before the resist film pattern forming process. For the membrane cleaning, a known cleaning method can be used. However, it is preferable to use a cleaning method other than the cleaning method using a cleaning liquid (for example, sulfuric acid and water) containing a sulfur (S) component.

[Example]

Hereinafter, the present invention will be described more specifically based on examples.

Example 1 and Comparative Example 1

In Embodiment 1 and Comparative Example 1, a phase shift mask blank having a phase shift film (material: CrCON) and a phase shift mask manufactured using the phase shift mask blank will be described.

The phase shift mask blank 1 of the first embodiment is manufactured by performing the VUV irradiation process on the outermost surface 3a of the phase shift film 3, Are produced without performing the VUV irradiation process on the outermost surface of the phase shift film, they are different from each other.

A. Phase Shift Mask Blank and Manufacturing Method Thereof

A synthetic quartz glass substrate of 3345 size (330 mm x 450 mm x 5 mm) was prepared as the transparent substrate 2 in order to manufacture the phase shift mask blank 1 of Example 1 and Comparative Example 1 described above .

Thereafter, the transparent substrate 2 is brought into the in-line sputtering apparatus 11 in which the sputtering targets made of chromium shown in Fig. 3 are arranged, and as shown in Figs. 1 and 2 (a) A phase shift film 3 (film thickness: 125 nm) containing chromium oxide carbonitride (CrOCN) was formed on the main surface of the substrate 2. [

The phase shift film 3 is formed of argon (Ar) gas, carbon dioxide (CO ₂ ) gas and nitrogen (N ₂ ) gas from a second gas inlet port GA12 disposed on the downstream side of the first sputtering target 13 made of chromium ₂₎ mixed gas (Ar gas containing: by the transport speed of the introduction of 35sc㎝), and the sputter power 3.55㎾, the transparent substrate 2 as 200㎜ / minute: 46sc㎝, N _2: 46sc㎝, CO ₂ , And reactive sputtering was performed to form a film on the transparent substrate 2. The phase shift film 3 (film thickness: 125 nm) was formed by one-time film formation.

Thereafter, the VUV irradiation process was performed on the outermost surface 3a of the phase shift film 3.

(Not shown) for irradiating VUV (xenon excimer light, wavelength 172 nm) at an energy of 40 mW / cm 2 is used as the VUV irradiation process, and irradiation of the uppermost surface 3a of the phase shift film 3 And irradiation corresponding to energy of 45 J / cm 2 was performed.

Thus, the phase shift mask blank 1 of Example 1 in which the phase shift film 3 having undergone the VUV irradiation process was formed on the transparent substrate 2 was obtained as shown in Fig. 2 (b).

On the other hand, the phase shift mask blank of Comparative Example 1 in which the phase shift film 3 not subjected to the VUV irradiation process was formed on the transparent substrate 2 was obtained.

The film density of the outermost surface 3a of the phase shift film 3 of the phase shift mask blank 1 of Example 1 and Comparative Example 1 was measured by X-ray reflectance analysis (XRR).

The film density of the phase shift film 3 at the depth of 2.2 nm from the surface layer was measured for the film density of the outermost surface 3a. As a result, the film density of the outermost surface 3a of the phase shift film 3 of Example 1 was 2.33 g / cm 3, and the film density of the outermost surface 3a of the phase shift film 3 of Comparative Example 1 1.92 g / cm 3. The numerical value Fit R indicating the validity of the fitting when the film density was calculated was 0.013 in Example 1 and 0.012 in Comparative Example 1. [

The composition of the phase shift film 3 of the phase shift mask blank 1 of Example 1 and the phase shift film of the phase shift mask blank of Comparative Example 1 were analyzed by X-ray photoelectron spectroscopy (XPS) .

8 is a graph showing the results of the compositional analysis of the phase shift mask blank of Comparative Example 1 by XPS in the depth direction and FIG. 9 is a graph showing the results of analysis of composition in the depth direction by XPS for the phase shift mask blank 1 of Example 1 . 8 and 9, the abscissa indicates the depth (nm) from the outermost surface 3a of the phase shift film 3, and the ordinate indicates the atomic composition percentage (atomic%).

Referring to Fig. 8, the bulk portion of the phase shift film in Comparative Example 1 is a region having a depth of about 10.0 nm to about 115 nm which hardly changes the content of each element. The composition gradient region is a region from the outermost surface (about 0.1 nm) to the shallowest end (about 10.0 nm) of the bulk portion where the content of each element varies greatly. Since the deep portion where silicon (Si) appears is a synthetic quartz glass substrate (transparent substrate 2), the vicinity of about 127 nm in which silicon (Si) starts to appear starts from the phase shift film 3 and the transparent substrate 2). The region near the transparent substrate is a region of about 10 nm from the interface to the outermost surface side.

Referring to Fig. 9, the bulk portion B of the phase shift film 3 in Example 1 is a region having a depth of about 10.0 nm to about 115 nm which hardly changes the content of each element. The composition gradient region R1 is a region from the outermost surface 3a (about 0.1 nm) to the shallowest end (about 10.0 nm) of the bulk portion B, in which the content of each element varies greatly. A depth of about 125 nm at which silicon (Si) starts to appear starts from the phase shift film 3 and the transparent substrate 2 (Si) because the deep portion in which silicon (Si) appears is a synthetic quartz glass substrate (transparent substrate 2) 2). The region R2 in the vicinity of the transparent substrate is a region of about 10 nm from the interface to the outermost surface side.

In both cases of Comparative Example 1 and Example 1, the variation range of the content of each element of chromium (Cr), oxygen (O), nitrogen (N) and carbon (C) is small in the bulk portion and is substantially uniform. The content of each element of chromium (Cr), oxygen (O), nitrogen (N), and carbon (C) in the compositionally graded region and the vicinity of the transparent substrate varied greatly in both of Comparative Example 1 and Example 1 .

The ratio (O / Cr) of oxygen to chromium, which decreases from the outermost surface 3a toward the film depth direction, calculated from the numerical data of Figs. 8 and 9 and the ratio Comparing Example 1 and Comparative Example 1 with respect to the ratio of nitrogen to chromium (N / Cr).

FIG. 10 shows the results of analysis of O / Cr in the depth direction by XPS, and FIG. 11 shows the results of N / Cr analysis in the depth direction by XPS. 10 and 11 show the depth (nm) from the outermost surface 3a of the phase shift film 3, the vertical axis of FIG. 10 represents O / Cr, the vertical axis of FIG. 11 represents N / Cr have.

First, as is clear from Fig. 10, Example 1 and Comparative Example 1 are compared with respect to the change of O / Cr in the film depth direction in the composition gradient region. The O / Cr of the first embodiment shows the maximum value (2.20) on the outermost surface 3a, decreases from the outermost surface 3a toward the film depth direction, and sharply decreases to a film depth of about 3 nm. On the contrary, the O / Cr of Comparative Example 1 exhibited the maximum value (1.96) on the outermost surface, decreased from the outermost surface toward the film depth direction, and decreased to a film depth of about 3 nm. That is, the maximum value of O / Cr (1.96) of Comparative Example 1 is increased from the maximum value of O / Cr of Example 1 (2.20). In addition, the reduction rate of O / Cr in Example 1 is larger than that of Comparative Example 1. As apparent from the results, since the difference between Example 1 and Comparative Example 1 is the presence or absence of the VUV irradiation process, the maximum value of O / Cr is increased by the VUV irradiation process, and the reduction rate of O / Cr is also large It can be seen that it will be lost. 10, the maximum value of O / Cr in the first embodiment is two or more.

Next, as apparent from Fig. 11, the variation of N / Cr in the film depth direction in the composition gradient region is compared with Example 1 and Comparative Example 1. N / Cr of Comparative Example 1 represents the maximum value (0.49) on the outermost surface, decreases from the outermost surface toward the film depth direction, and rapidly decreases to a film depth of about 3 nm. On the contrary, the N / Cr of the first embodiment shows the maximum value (0.34) on the outermost surface 3a, decreases from the outermost surface 3a toward the film depth direction, and decreases to a film depth of about 3 nm . That is, the N / Cr maximum value (0.34) of Example 1 is reduced to the N / Cr maximum value (0.49) of Comparative Example 1. In addition, the reduction ratio of N / Cr in Example 1 is smaller than that of Comparative Example 1. As apparent from this result, since the difference between Example 1 and Comparative Example 1 is the presence or absence of the VUV irradiation process, the maximum value of N / Cr is decreased by the VUV irradiation process, . 11, the maximum value of N / Cr in Example 1 is 0.45 or less.

The transmittance of the phase shift film 3 of each phase shift mask blank 1 of Example 1 and Comparative Example 1 was measured by a spectrophotometer U-4100 manufactured by Hitachi High-Technologies Corporation, The phase difference was measured by MPM-100. The values of transmittance in Example 1 and Comparative Example 1 are all based on Air.

The transmittance and the phase difference of the phase shift film 3 were measured by using the phase shift film 3 (thickness of the film) on the main surface of the 6025 size (152 mm x 152 mm) transparent substrate 2 set in the same substrate holder (not shown) (Dummy substrate) to which a phase shift film having a film thickness of 125 nm was added.

As a result, the transmittance spectrum of Example 1 at a wavelength of 200 nm to 800 nm was substantially the same as that of Comparative Example 1 in which the VUV irradiation process was not performed. From this result, it was found that even if the VUV irradiation process is performed, the desired transmittance spectrum can be maintained without changing the transmittance spectrum before performing the VUV irradiation process.

The retardation of Example 1 and Comparative Example 1 at a wavelength of 365 nm was 184.6 DEG. From this result, it was found that even when the VUV irradiation process is performed, the desired phase difference can be maintained without changing the phase difference before performing the VUV irradiation process.

The reflectance of the phase shift film 3 of the phase shift mask blank 1 of Example 1 and Comparative Example 1 was measured by a spectrophotometer U-4100 manufactured by Hitachi High-Technologies Corporation.

As a result, the reflectance spectrum of Example 1 at a wavelength of 200 nm to 800 nm was substantially the same as the reflectance spectrum of Comparative Example 1 in which the VUV irradiation process was not performed. From these results, it was found that even when the VUV irradiation process is performed, the desired reflectance spectrum can be maintained without changing the reflectance spectrum before performing the VUV irradiation process.

B. Phase shift masks and methods for making them

In order to produce the phase shift masks of Example 1 and Comparative Example 1 using the phase shift mask blank of Example 1 and Comparative Example 1 manufactured as described above, first, the phase of Example 1 and Comparative Example 1 The photoresist film 5 was coated on the phase shift film 3 of the shift mask blank using a resist coating apparatus.

Thereafter, a photoresist film 5 having a film thickness of 1000 nm was formed through a heating and cooling process.

Thereafter, the photoresist film 5 is drawn by using a laser beam drawing apparatus, and after the development and rinsing process, a line having a width of the line pattern of 2.0 mu m and the width of the space pattern of 2.0 mu m is formed on the phase shift film 3, Thereby forming a resist film pattern 5 'in an and space pattern.

Thereafter, using the resist film pattern 5 'as a mask, the phase shift film 3 is wet-etched by a chromium etchant containing ceric ammonium nitrate and perchloric acid to form a phase shift film pattern 3' Respectively.

Thereafter, the resist film pattern 5 'was peeled off.

In this manner, the phase shift mask 30 (transparent substrate / phase (phase)) of Example 1 in which the phase shift film pattern 3 'patterned with the phase shift film 3 subjected to the VUV irradiation process on the transparent substrate 2 was formed Shift film pattern).

On the other hand, the phase shift mask (transparent substrate / phase shift film pattern) of Comparative Example 1 in which the phase shift film pattern 3 'formed by patterning the phase shift film 3 not subjected to the VUV irradiation process was formed on the transparent substrate 2, .

The etched end faces of the edge portions of the phase shift mask 30 of the first embodiment and the phase shift mask 3 'of the phase shift mask of the first comparative example were removed before the resist film pattern 5' And observed with an electron microscope.

12 is a cross-sectional photograph of the edge portion of the phase shift film pattern 3 'of the phase shift mask of Example 1, and FIG. 13 is a cross-sectional photograph of the edge portion of the phase shift film pattern 3' of the phase shift mask of Comparative Example 1 And Fig. 14 is a cross-sectional view for explaining a cross-sectional angle (?) Serving as a judgment index of the cross-sectional shape of the edge portion.

14, the film thickness of the phase shift film 3 is T, the auxiliary line extending from the outermost surface 3a to the depth of T / 10 is defined as L1, and T / 10, the intersection point of the etched end face F of the phase shift film 3 and the auxiliary line L1 is C1, and the intersection of the etched end face F and the auxiliary line L2 is C2. Here, the cross-sectional angle? Is an angle formed by the ferry connecting the intersection C1 and the intersection C2 to the main surface of the transparent substrate 2.

The resist interfacial angle is an angle formed by the etched end face F near the resist and the outermost surface 3a. The interfacial angle of the transparent substrate is an angle formed by the etched end face F near the transparent substrate and the main surface of the transparent substrate.

The length of the tapered surface is defined by a point at which one point of the intersection of the etched end face F and the outermost surface 3a in the vicinity of the resist is projected in the vertical direction as it is on the main surface of the transparent substrate, It is the length of one point of the tip of the truncated part.

The resist interfacial angle of the etched section of the edge portion of Example 1 shown in Fig. 12 was 90 deg., The interface angle of the transparent substrate was 90 deg., The tapered length was 0 nm, and the sectional angle [ .

On the other hand, the resist interfacial angle of the etched section of the edge portion of Comparative Example 1 shown in Fig. 13 is 140 deg., The transparent substrate interfacial angle is 38 deg., The tapered length is 150 nm, °. In addition, the etched cross section of Comparative Example 1 in which the VUV irradiation step was not performed became a tapered shape to be sagged.

As is apparent from these results, it can be seen that the etched cross section in Example 1 has a significantly larger cross-sectional angle (?) Than that of the etched cross-section in Comparative Example 1 and is closer to a more vertical cross-sectional shape It was. That is, the VUV irradiation process increases the cross-sectional angle? Of the etched section of the edge portion.

Next, CD deviation of the phase shift film pattern of the phase shift mask of Example 1 was measured by SIR8000 manufactured by Seiko Instrument Nanotechnology. The measurement of the CD deviation was performed at a position of 5 x 5 with respect to a region of 270 mm x 390 mm excluding the peripheral region of the substrate. The CD deviation is a shift width from the target line and space pattern (width of line pattern: 2.0 m, width of space pattern: 2.0 m). In the following Examples and Comparative Examples, the same apparatus was used for measurement of CD deviation.

The CD deviation was as very good as 0.05 탆.

It was found that the CD deviation of the phase shift film pattern of the phase shift mask of Comparative Example 1 was 0.20 mu m and was larger than that of Example 1. [

Example 2 and Comparative Example 2

In Example 2 and Comparative Example 2, a phase shift mask blank having a phase shift film (material: CrCON) deposited under film formation conditions different from those in Example 1 and Comparative Example 1, and a phase produced using this phase shift mask blank The shift mask will be described.

The phase shift mask blank 1 of the second embodiment is manufactured by performing the VUV irradiation process on the outermost surface 3a of the phase shift film 3, Are produced without performing the VUV irradiation process on the outermost surface of the phase shift film, they are different from each other.

A. Phase Shift Mask Blank and Manufacturing Method Thereof

As the transparent substrate 2, a synthetic quartz glass substrate having the same size as that of Example 1 and Comparative Example 1 was prepared.

In the second embodiment and the second comparative example, in the phase shift film forming step, the first gas introducing port 13 disposed on the upstream side of the first sputtering target 13 made of chromium of the sputtering apparatus 11 shown in Fig. A mixed gas of the same components as in Example 1 and Comparative Example 1 was introduced from GA11, and the sputter power was set to 3.40 kW. Other film forming conditions were the same as in Example 1 and Comparative Example 1, except that the phase shift film 3 (film thickness: 125 nm) was formed by one-time film formation.

Thereafter, similarly to Example 1, the VUV irradiation process with respect to the outermost surface 3a of the phase shift film 3 was performed to obtain the phase shift mask blank 1 of Example 2.

On the other hand, the phase shift mask blank of Comparative Example 2 in which the phase shift film 3 not subjected to the VUV irradiation process was formed on the transparent substrate 2 was obtained.

The composition of the phase shift film 3 of the phase shift mask blank 1 of Example 2 and the phase shift film of the phase shift mask blank of Comparative Example 2 were analyzed by XPS in the depth direction.

As a result, O / Cr in the composition gradient region R1 of Example 2 exhibited a maximum value of 2 or more (2.19) on the outermost surface 3a and decreased from the outermost surface 3a toward the depth of the film. On the other hand, O / Cr in the composition gradient region of Comparative Example 2 exhibited a maximum value of less than 2 (1.95) on the outermost surface, and decreased from the outermost surface toward the depth of the film. In N / Cr in the composition gradient region of Comparative Example 2, the maximum value (0.49) exceeding 0.45 on the outermost surface decreased from the outermost surface toward the film depth direction. On the other hand, N / Cr in the composition gradient region R1 of Example 2 exhibited a maximum value (0.32) of 0.45 or less on the outermost surface 3a and decreased from the outermost surface 3a toward the film depth direction.

The film thickness of the outermost surface 3a of the phase shift mask blank of Example 2 and Comparative Example 2 was measured by X-ray reflectance analysis (XRR) in the same manner as in Example 1 and Comparative Example 1.

As a result, the film density of the outermost surface 3a of the phase shift film 3 of the phase shift mask blank 1 of Example 2 was 2.28 g / cm 3, the phase shift of the phase shift mask blank 1 of Comparative Example 2 The film density of the outermost surface 3a of the film 3 was 1.89 g / cm 3.

The phase shift film 3 of the phase shift mask blank 1 of Example 2 has the phase shift of the phase shift mask blank of Comparative Example 2 which is not subjected to the VUV irradiation treatment as in the relation of Example 1 and Comparative Example 1 The transmittance, the reflectance, and the phase difference were hardly changed.

B. Phase shift masks and methods for making them

Using the phase shift mask blanks of Example 2 and Comparative Example 2 manufactured as described above, the phase shift masks of Example 2 and Comparative Example 2 were produced in the same manner as in Example 1.

In this manner, the phase shift mask 30 (transparent substrate / phase (phase)) of Embodiment 2 in which the phase shift film 3 'patterned with the phase shift film 3 subjected to the VUV irradiation process is formed on the transparent substrate 2 is formed Shift film pattern).

On the other hand, in the phase shift mask of Comparative Example 2 in which the phase shift film pattern 3 'on which the phase shift film 3 not subjected to the VUV irradiation process was formed on the transparent substrate 2 was formed (the transparent substrate / phase shift film pattern ).

The etched end faces of the edge portions of the phase shift mask 30 of the second embodiment and the phase shift mask 3 'of the phase shift mask of the second comparative example were removed before the resist film pattern 5' And observed with an electron microscope.

As shown in Fig. 15, the resist interfacial angle of the etched section of the edge portion of Example 2 is 130 deg., The interface angle of the transparent substrate is 50 deg., The length of the tapered portion is 80 nm, 50 °.

On the other hand, as shown in Fig. 16, the resist interfacial angle of the etched section of the edge portion of Comparative Example 2 is 150 deg., The transparent substrate interfacial angle is 28 deg., The tapered length is 230 nm, ) Was 30 [deg.]. That is, the etched cross section of Comparative Example 2 in which the VUV irradiation step was not performed became a tapered shape which was longer than Example 2 or Comparative Example 1.

As apparent from these results, it was found that the etched cross section in Example 2 had a significantly larger cross sectional angle (?) Than that of the etched cross section in Comparative Example 2, and was closer to a more vertical cross sectional shape . That is, by the VUV irradiation process, the cross-section angle? Of the etched section of the edge portion becomes large. Further, in the case of forming the phase shift film 3 made of CrCON as a constituent material, a mixed gas (sputter gas) in the phase shift film forming step is formed on the downstream side of the sputtering target related to film formation of the phase shift film (Example 1), the cross-sectional angle? Is larger than that in the case of feeding from the upstream side of the sputtering target (Example 2).

Next, the CD deviation of the phase shift film pattern of the phase shift mask 30 of Example 2 was measured in the same manner as in Example 1.

The CD deviation was 0.12 占 퐉.

It was found that the CD deviation of the phase shift film pattern of the phase shift mask of Comparative Example 2 was 0.22 mu m and was larger than that of Example 2. [

Example 3

In Embodiment 3, a phase shift mask blank in which the material of the phase shift film 3 is CrON and a phase shift mask manufactured using the phase shift mask blank will be described.

A. Phase Shift Mask Blank and Manufacturing Method Thereof

As the transparent substrate 2, a synthetic quartz glass substrate having the same size as that of Example 1 was prepared.

Thereafter, the transparent substrate 2 is introduced into the in-line sputtering apparatus 11 shown in Fig. 3, and the phase shift film 3 (chromium oxide 157 nm) was formed by a single film deposition to obtain a phase shift mask blank (1).

The phase shift film 3 is formed of a mixed gas (Ar: 46sc (Ar) gas containing argon (Ar) gas and nitrogen monoxide (NO) gas from the second gas inlet GA12 on the downstream side of the first sputtering target 13 made of chromium Cm, NO: 70 sccm) was introduced and reactive sputtering was performed on the transparent substrate 2 at a sputtering power of 8.0 kW and a transporting speed of the transparent substrate 2 of about 400 mm / min.

Thereafter, the VUV irradiation process with respect to the outermost surface 3a of the phase shift film 3 was performed under the same irradiation conditions as in the first embodiment.

Thus, a phase shift mask blank 1 having a phase shift film 3 having undergone the VUV irradiation process on the transparent substrate 2 was obtained.

The composition of the phase shift film 3 of the phase shift mask blank 1 of Example 3 in the depth direction was analyzed by XPS.

As a result, in O / Cr in the composition gradient region R1, the maximum value (2.11) of 2 or more on the outermost surface 3a was decreased toward the film depth direction from the outermost surface 3a. In N / Cr in the composition gradient region R1, the maximum value (0.32) of 0.45 or less in the outermost surface 3a was decreased from the outermost surface 3a toward the film depth direction.

The film density of the phase shift film 3 of the phase shift mask blank 1 of Example 3 was measured by X-ray reflectance analysis (XRR) in the same manner as in Example 1. [

As a result, the film density of the outermost surface 3a of the phase shift film 3 of the phase shift mask blank 1 of Example 3 rose from 1.85 g / cm3 to 2.21 g / cm3 before the VUV irradiation treatment.

In addition, the phase shift film 3 of the phase shift mask blank 1 of Example 3 showed little change in transmittance, reflectance and phase difference as compared with that before the VUV irradiation treatment.

B. Phase shift masks and methods for making them

A phase shift mask 30 having a phase shift film pattern 3 'formed by patterning the phase shift film 3 subjected to the VUV irradiation process on the transparent substrate 2 was obtained in the same manner as in Example 1.

The etched section of the edge portion of the phase shift film pattern 3 'of the phase shift mask 30 of Example 3 was observed by a scanning electron microscope before peeling off the resist film pattern 5'.

As a result, the resist interfacial angle of the etched section of the edge portion of Example 3 was 90 °, the interface angle of the transparent substrate was 90 °, the tapered length was 0 nm, and the sectional angle θ was 90 °. That is, the etched cross section of the phase shift film pattern 3 'of Example 3 using CrON as a material is similar to the etched cross section of the phase shift film pattern 3' of Example 1 using CrCON as a constituent material , And it became a completely vertical cross-sectional shape without any hanging.

Next, the CD deviation of the phase shift film pattern of the phase shift mask 30 of Example 3 was measured in the same manner as in Example 1.

The CD deviation was 0.055 占 퐉.

Example 4

In Embodiment 4, a phase shift mask blank having a phase shift film (material: CrON) deposited under film formation conditions different from Embodiment 3 and a phase shift mask manufactured using this phase shift mask blank will be described.

A. Phase Shift Mask Blank and Manufacturing Method Thereof

As the transparent substrate 2, a synthetic quartz glass substrate having the same size as that of Example 1 was prepared.

In the fourth embodiment, in the phase shift film forming step, the first gas introduction port GA11 arranged on the upstream side of the first sputtering target 13 made of chrome, of the sputtering apparatus 11 shown in Fig. 3, A mixed gas of the same components as in Example 3 was introduced. The other film forming conditions were the same as in Example 3 to form the phase shift film 3 (film thickness 157 nm) by one-time film formation.

Thereafter, the VUV irradiation process with respect to the outermost surface 3a of the phase shift film 3 was performed under the same irradiation conditions as in the first embodiment.

Thus, the phase shift mask blank 1 having the phase shift film 3 formed by patterning the phase shift film 3 subjected to the VUV irradiation process on the transparent substrate 2 was obtained.

The composition of the phase shift film 3 of the phase shift mask blank 1 of Example 4 was analyzed in the depth direction by XPS.

As a result, O / Cr in the composition gradient region R1 exhibited a maximum value of 2 or more (2.10) in the outermost surface 3a and decreased from the outermost surface 3a toward the film depth direction. In N / Cr in the composition gradient region R1, the maximum value (0.31) of 0.45 or less in the outermost surface 3a was decreased from the outermost surface 3a toward the film depth direction.

The film density of the phase shift film 3 of the phase shift mask blank 1 of Example 4 was measured by X-ray reflectance analysis (XRR) in the same manner as in Example 1. [

As a result, the film density of the outermost surface 3a of the phase shift film 3 of the phase shift mask blank 1 of Example 4 rose from 1.84 g / cm3 to 2.19 g / cm3 before the VUV irradiation treatment.

In addition, the phase shift film 3 of the phase shift mask blank 1 of Example 4 showed almost no change in transmittance, reflectance and phase difference as compared with that before the VUV irradiation treatment.

B. Phase shift masks and methods for making them

A phase shift mask 30 having a phase shift film pattern 3 'formed on a transparent substrate 2 was obtained in the same manner as in Example 1. [

The etched section of the edge portion of the phase shift film pattern 3 'of the phase shift mask 30 of Example 4 was observed by a scanning electron microscope before peeling off the resist film pattern 5'.

As a result, the resist interfacial angle of the etched section of the edge portion of Example 4 was 122 deg., The transparent substrate interface angle was 58 deg., The tapered length was 70 nm, and the sectional angle [theta] was 58 deg.

As evident from the results, the etched cross section in Example 4 has a significantly larger cross-sectional angle (?) Than that of the etched cross-sections in Comparative Examples 1 and 2, and the fact that it is closer to a more vertical cross- I found out. Further, in the case of forming the phase shift film 3 made of CrON as the constituent material (Examples 3 and 4), the case of forming the phase shift film 3 made of CrCON as the constituent material (Examples 1 and 2 (Example 3) in the case where the mixed gas (sputter gas) in the phase shift film forming step is supplied from the downstream side of the sputtering target relating to the film formation of the phase shift film, the supply from the upstream side of the sputtering target It is found that the cross-sectional angle? Becomes larger than the case (Example 4).

Next, CD deviation of the phase shift film pattern of the phase shift mask of Example 4 was measured in the same manner as in Example 1.

The CD deviation was 0.115 占 퐉.

In the above-described embodiment, the phase shift mask blank 1 having the phase shift film 3 formed on the transparent substrate 2 as a single layer film is described as an example, but the present invention is not limited to this. Layer film, a three-layer structure, or a four-layer structure made of the same material, the phase shift film 3 exhibits the same effects as those of the above-described embodiment.

In the above-described embodiment, the phase shift mask blank 1 in which only the phase shift film 3 is formed on the transparent substrate 2, and the phase shift film 3 'in which only the phase shift film pattern 3' Although an example of the mask 30 has been described, it is not limited thereto. Even in the case of the phase shift mask blank 10 (see Fig. 5) having the light-shielding film pattern 4 'and the phase shift film 3 on the transparent substrate 2, the phase shift film 3 and the phase shift film 3 Shielding film pattern 4 'and the phase shift film pattern 3' on the transparent substrate 2 in the case of the phase shift mask blank (see FIG. 6 (b)) having the resist film 5 (See FIG. 7 (e)), the same effects as those of the above-described embodiment are exhibited.

In the phase shift mask blank (not shown) having the phase shift film 3 and the light shield film 4 on the transparent substrate 2, the light shield film 4 formed on the phase shift film 3 is formed as a light shielding layer, Layer and an antireflection layer.

1, 10: phase shift mask blank
2: transparent substrate
3: Phase shift film
3a: Top surface
4:
5: Resist film
3 ': phase shift film pattern
4 ': light-shielding film pattern
5 ': resist film pattern
R1: composition gradient region
R2: region near the transparent substrate
B: bulk part
F: etched cross section
C1, C2: intersection
T: film thickness
θ: section angle
11: Sputtering device
LL: Loading chamber
SP1: First sputter chamber
BU: buffer chamber
SP2: Second sputter chamber
ULL: Take-out chamber
13: First sputtering target
GA11: First gas inlet
GA12: The second gas inlet
14: Second sputtering target
GA21: Third gas inlet
GA22: Fourth gas inlet
15: Third sputtering target
GA31: fifth gas inlet
GA32: Sixth gas inlet
30, 31: phase shift mask

Claims (16)

A phase shift mask blank in which a phase shift film containing chromium, oxygen, and nitrogen is formed on a transparent substrate,
A composition gradient region is formed in the phase shift film from the outermost surface thereof toward the film depth direction, and a ratio (O / Cr) of oxygen to chromium decreases from the outermost surface toward the film depth direction in the composition gradient region Wherein the maximum value is 2 or more and the maximum value of the ratio of nitrogen to chromium (N / Cr) decreasing from the outermost surface toward the film depth direction is 0.45 or less. The method according to claim 1,
Wherein the composition gradient region of the phase shift film is formed by vacuum ultraviolet ray irradiation processing on the outermost surface. 3. The method according to claim 1 or 2,
Wherein the film density of the outermost surface of the phase shift film is 2.0 g / cm 3 or more. 3. The method according to claim 1 or 2,
Wherein the film thickness of the composition gradient region is 0.1 nm or more and 10 nm or less. 3. The method according to claim 1 or 2,
Characterized in that the composition ratio of each element in the film depth direction in the phase shift film except the 10 nm region from the composition gradient region and the interface between the phase shift film and the transparent substrate to the outermost surface side is uniform. Blank. 3. The method according to claim 1 or 2,
Wherein the phase shift film further contains carbon. A phase shift mask blank manufacturing method for forming a phase shift film containing chromium, oxygen, and nitrogen on a transparent substrate by a sputtering method,
A film forming step of forming the phase shift film on the transparent substrate;
And a vacuum ultraviolet ray irradiation processing step of performing vacuum ultraviolet ray irradiation processing on the outermost surface of the phase shift film that has been formed,
Wherein the vacuum ultraviolet ray irradiation treatment step includes a step of irradiating the surface of the phase shift film with a composition ratio of oxygen to chromium which decreases from the outermost surface toward the film depth direction in a composition gradient region formed from the outermost surface of the phase shift film toward the film depth direction, Cr) is changed to 2 or more, and the maximum value of the ratio of nitrogen (N / Cr) to chromium which decreases from the outermost surface toward the film depth direction is changed to 0.45 or less. Gt; 8. The method of claim 7,
Wherein the vacuum ultraviolet ray irradiation treatment step changes the film density of the outermost surface of the phase shift film to 2.0 g / cm 3 or more. 9. The method according to claim 7 or 8,
Characterized in that the composition ratio of each element in the film depth direction in the phase shift film except the 10 nm region from the composition gradient region and the interface between the phase shift film and the transparent substrate to the outermost surface side is uniform. Lt; / RTI &gt; 9. The method according to claim 7 or 8,
Wherein the film forming step is a step of forming the phase shift film by laminating the same material. 9. The method according to claim 7 or 8,
Wherein the film forming step is performed by reactive sputtering using a sputtering target containing chromium and a mixed gas containing an inert gas and an active gas for oxidizing and nitriding the phase shift film. Gt; 12. The method of claim 11,
Wherein the mixed gas further comprises an active gas for carbonizing the phase shift film. 12. The method of claim 11,
Wherein the film forming step is performed by an in-line sputtering apparatus. 14. The method of claim 13,
Wherein the mixed gas is supplied from the downstream side to the sputtering target in the transport direction of the transparent substrate. 9. The method according to claim 7 or 8,
The vacuum ultraviolet ray irradiation treatment step is a step of increasing the rate of decrease of the ratio of oxygen to chromium (O / Cr) in the composition gradient region to that after the vacuum ultraviolet ray irradiation treatment before the vacuum ultraviolet ray irradiation treatment, (N / Cr) is reduced after the vacuum ultraviolet ray irradiation treatment before the vacuum ultraviolet ray irradiation treatment. The phase shift mask blank according to claim 1, the phase shift mask blank according to claim 2, the phase shift mask blank produced by the method for manufacturing a phase shift mask blank according to claim 7, and the phase shift mask blank A resist film pattern is formed on the phase shift film of any one of the phase shift mask blank manufactured by the manufacturing method of the present invention and the phase shift film is subjected to wet etching using the resist film pattern as a mask, And forming a phase shift film pattern on the substrate.

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