KR20190047032A - Halftone mask, photomask blank, and manufacturing method of halftone mask - Google Patents

Abstract

[PROBLEMS] To provide a multi-gradation halftone mask capable of exposing a fine photoresist pattern.
[MEANS FOR SOLVING PROBLEMS] A phase shifting portion is formed on a transparent substrate, the phase shifting portion including a transflective portion and a phase shifting film, the phase shift film inverting the phase of the exposure light, Is lower than the transmittance. Further, a laminated film of the semi-transparent film, the phase shift film and the etching stopper film is formed at the boundary where the semitransmissive portion and the phase shift portion are adjacent to each other, and the etching stopper film is not etched by the etching solution of the semitransmissive film and the phase shift film . As a result, a photomask having both a halftone effect and a phase shift effect is realized.

Description

Halftone mask, photomask blank, and manufacturing method of halftone mask

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a halftone mask, a photomask blank, and a method of manufacturing a halftone mask, which are multi-gradation photomasks used in flat panel displays and the like.

In a technical field such as a flat panel display, a multi-gradation photomask called a halftone mask, which has a function of limiting the amount of exposure with the transmittance of a semi-transmissive film, is used.

The halftone mask can realize a multi-gradation photomask having three gradations or more by using a transparent substrate, a semi-transparent film, and a light-shielding film by using a semi-transparent film having an intermediate transmittance between the transparent substrate and the light-shielding film.

By using the halftone mask disclosed in Patent Document 1, a photoresist pattern having a different film thickness can be formed by one exposure, and the number of lithography processes in the manufacturing process of a flat panel display can be reduced, Can be reduced.

For example, in a liquid crystal display device using a thin film transistor (TFT), a photoresist pattern having a different film thickness is formed by one exposure process in the channel region and the source / drain electrode formation region of the TFT, And is used as a technique for reducing the manufacturing cost accordingly.

On the other hand, miniaturization of the wiring pattern is increasingly demanded because of the high quality of the flat panel display. When a projection exposure apparatus tries to expose a pattern close to the resolution limit, in order to secure an exposure margin, a phase shifter for inverting the phase to the edge part of the light shielding area, as disclosed in Patent Document 2, A phase shift mask is proposed.

Japanese Patent Application Laid-Open No. H11-227391 Japanese Patent Laid-Open Publication No. 2011-13283

The halftone mask can contribute to the reduction of the lithography process, but the change in the exposure light intensity distribution at the boundary between the semitransparent film and the light shielding film is comparatively gentle, and therefore, the photoresist film exposed using the halftone mask has a boundary And the process margin is lowered, and it is difficult to form a fine pattern.

By using the phase shift mask, the resolution is improved and the pattern can be further miniaturized. However, since the phase shift mask is a technique for a binary mask, it is impossible to reduce the lithography process such as a halftone mask. Therefore, when used in the manufacture of a flat panel display, it can not contribute to the reduction of the lithography process.

As described above, with the conventional photomask, it has been impossible to combine the problem of reduction in manufacturing cost and resolution of a flat panel display.

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide a photomask capable of both reducing the lithography process and further finishing the pattern, a photomask blanks used in the production, and a method of manufacturing the photomask do.

In the photomask according to the embodiment of the present invention,

A transflective portion, a phase shift portion, a boundary portion, and a transparent portion on a transparent substrate,

Wherein the transparent portion comprises a portion where the transparent substrate is exposed,

Wherein the transflective portion is formed of a transflective film provided on the transparent substrate,

Wherein the phase shift portion is formed of a phase shift film provided on the transparent substrate,

Wherein the boundary portion is formed in a region where the semitransmissive portion and the phase shift portion are adjacent to each other,

Wherein a width of the boundary portion is equal to or less than a predetermined width,

Wherein the boundary portion is formed of a laminated structure film in which the phase shift film, the etching stopper film, and the semitransmissive film are formed in this order, while the etching stopper film of the semitransmissive portion, the phase shifting portion, And,

The width of the boundary portion is not more than the resolution limit of the transparent exposure apparatus in which the photomask is used

.

Further, in the photomask according to the embodiment of the present invention,

A transparent substrate is provided with a transflective portion, a phase shift portion, a boundary portion, and a transparent portion,

Wherein the transparent portion comprises a portion where the transparent substrate is exposed,

Wherein the transflective portion is formed of a semi-transparent film provided on the transparent substrate,

Wherein the phase shift portion is formed of a phase shift film provided on the transparent substrate,

Wherein the boundary portion is formed in a region where the semitransmissive portion and the phase shift portion are adjacent to each other,

Wherein a width of the boundary portion is equal to or less than a predetermined width,

Wherein the boundary portion is formed with the semitransmissive film, the etching stopper film, and the phase shift film in this order, while the etching stopper film of the semitransmissive portion, the phase shifting portion, and the transmissive portion except for the boundary portion is removed,

The width of the boundary portion is not more than the resolution limit of the projection exposure apparatus in which the photomask is used

.

In the photomask according to the embodiment of the present invention,

The photomask according to claim 1 or 2, wherein the phase shift film has a transmittance of 1 to 10% with respect to the exposure light, and the phase of the exposure light is changed.

In the photomask according to the embodiment of the present invention,

And the transmissivity of the transflective film to the exposure light is 10 to 60%.

With this configuration, the semi-transmissive portion has intermediate light transmittance of the phase shifting portion and the transmissive portion, and a photomask having multiple gradations can be obtained by the transflective portion, the phase shifting portion, and the transparent portion. In addition, by adjoining the transflective portion and the phase shift portion, the profile of the exposure light at the boundary portion between the transflective portion and the phase shifting portion can be abruptly changed, the shape of the exposed photoresist can be improved, and the pattern can be miniaturized. As a result, a photomask having both a halftone effect and a phase shift effect can be obtained.

In the photomask according to the embodiment of the present invention,

The phase shift film and the semi-permeable film can be etched by the same etching liquid, and the etching stopper film has etching selectivity to the etching liquid.

Specifically, for example, the etching stopper film is made of a Ti-based film, and the phase shift film is made of a Cr oxide film.

With such a configuration, in the process of manufacturing the photomask, the photomask can be easily manufactured by using the wet etching.

In the photomask according to the embodiment of the present invention,

The? Of the boundary portion is set to an alignment error of the photomask drawing apparatus and is characterized by being below the resolution limit of the projection exposure apparatus in which the photomask is used.

With this configuration, it is possible to make the transflective portion and the phase shift portion adjacent to each other without adversely affecting exposure of the photoresist by the etching stopper film at the boundary portion.

In the photomask blank according to the embodiment of the present invention,

A photomask blanks for manufacturing the photomask,

And the phase shift film and the etching stopper film are stacked in this order on the transparent substrate.

By using the photomask blanks having such a constitution, a multi-tone mask can be formed by forming a transflective film on the photomask blanks in accordance with the specification or use of the customer. As a result, the manufacturing time of the photomask having both the halftone effect and the phase shift effect and the desired characteristics can be shortened.

In the method of manufacturing a photomask according to the embodiment of the present invention,

A step of laminating a phase shift film and an etching stopper film on a transparent substrate in this order;

A step of forming a first photoresist film,

A step of patterning the first photoresist film;

Etching the etching stopper film using the first photoresist film as a mask,

Etching the phase shift film using the etching stopper film as a mask,

Removing the first photoresist film;

A step of forming a transflective film,

A step of forming a second photoresist film,

Patterning the second photoresist film so that the etch stopper film and the projection exposure apparatus have a width less than a resolution limit,

Etching the semi-transparent film with the second photoresist film as a mask,

Removing the second photoresist film;

Etching the etching stopper film on the phase shift film using the transflective film as a mask to remove the etching stopper film except for the boundary portion

And a control unit.

Further, in the method of manufacturing a photomask according to the embodiment of the present invention,

A step of laminating a semi-transparent film and an etching stopper film on a transparent substrate in this order;

A step of forming a third photoresist film,

A step of patterning the third photoresist film;

Etching the etching stopper film using the third photoresist film as a mask,

Etching the transflective film using the etching stopper film as a mask,

Removing the third photoresist film;

A step of forming a phase shift film,

A step of forming a fourth photoresist film,

Patterning the fourth photoresist film so that a width less than a resolution limit of the etch stopper film and the projection exposure apparatus overlap;

Etching the phase shift film using the fourth photoresist film as a mask,

Removing the fourth photoresist film,

Etching the etching stopper film on the transflective film with the phase shift film as a mask to remove the etching stopper film except for the boundary portion

And a control unit.

By such a manufacturing method of the photomask, patterning of the semi-transmissive film and the phase shift film becomes possible. In addition, it becomes possible to arrange the pattern of the transflective film and the pattern of the phase shift film adjacent to each other. As a result, it is possible to manufacture a photomask that goes both the halftone effect and the phase shift effect.

According to the present invention, it is possible to realize a multi-gradation halftone mask which can further reduce the pattern and reduce the lithography process. As a result, for example, it can contribute to a reduction in the manufacturing cost of a high-definition flat panel display.

1 is a cross-sectional view showing main steps of a photomask according to a first embodiment of the present invention.
2 is a cross-sectional view showing main steps of a photomask according to the first embodiment of the present invention.
3 is a cross-sectional view showing main steps of a photomask according to the first embodiment of the present invention.
4 is a comparative view of the inclination angle at the boundary between the photomask according to the first embodiment of the present invention and the photoresist film exposed by the conventional photomask.
5 is a cross-sectional view showing main steps of a photomask according to a second embodiment of the present invention.
6 is a cross-sectional view showing main steps of a photomask according to a second embodiment of the present invention.
7 is a cross-sectional view showing main steps of a photomask according to a second embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted, however, that the following embodiments are not intended to be construed as limiting the present invention. The same or similar members are denoted by the same reference numerals, and a description thereof may be omitted.

(Embodiment 1)

Hereinafter, the manufacturing process of Embodiment 1 of the halftone mask of the present invention will be described in detail.

1 (A), a phase shift film 12 is formed on a transparent substrate 11 such as synthetic quartz glass by sputtering or the like, and an etching stopper film 13 is formed thereon by a sputtering method or the like A photomask blank 10 is provided.

The phase shift film 12 has a phase shift angle of about 180 degrees and the phase of the exposure light is reversed and the light transmittance of the phase shift film 12 with respect to the exposure light is 1% to 10%.

When the light transmittance of the phase shift film 12 is excessively low, the phase shift effect is reduced, so that the typical light transmittance is 5 to 7 [%]. Specifically, for example, a Cr (chromium) oxide film or a Cr oxynitride film having a film thickness of 80 to 200 [nm] is used to adjust the film thickness and composition in accordance with required characteristics. It is not always necessary to be a single-layer film. For example, the film may be a film whose composition varies with respect to the film thickness direction or a film in which films having different compositions are laminated.

As the exposure light, g line, h line, i line, or a mixture of two or more of these lights can be used.

Here, approximately 180 [degrees] is specifically in the range of 180 10 [degrees], and if the range is within this range, the phase reversing effect can be sufficiently obtained.

The etching stopper film 13 is made of a material different from that of the phase shift film 12 and having a different etching characteristic. Specifically, as the etching stopper film 13, for example, a Ti (titanium) film (Ti, Ti oxide film, Ti oxynitride film or laminated film thereof) having a film thickness of 4 to 30 [ (Ni, Ni oxide film, Ni oxynitride film, or laminated film thereof), MoSi (molybdenum silicide) film, or the like is used.

Next, a first photoresist film 14 is formed on the etching stopper film 13 by a coating method.

Next, as shown in Fig. 1 (B), the first photoresist film 14 is exposed by, for example, a photomask drawing apparatus and then developed so that the first photoresist patterns 14a and 14b And 14c.

Next, as shown in Fig. 1 (C), the etching stopper film 13 is etched using the first photoresist patterns 14a, 14b and 14c as a mask to form patterns 13a, 13b and 13c of the etching stopper film do.

The etching can be performed by a wet etching method or a dry etching method. When the etching stopper film 13 is selectively etched with respect to the phase shift film 12, it is preferable to use a wet etching having a high selection ratio. The etching liquid may have a selectivity to the phase shift film 12 (having etching resistance), and a chemical solution capable of etching the etching stopper film 13 in accordance with the material of the etching stopper film 13 may be selected. For example, when a Ti-based film is used, a mixed solution of potassium hydroxide (KOH) and hydrogen peroxide water can be preferably used, but is not limited thereto.

Next, as shown in Fig. 2A, the first photoresist patterns 14a, 14b, and 14c are removed by ashing or the like, and then the patterns 13a, 13b, and 13c of the etching stopper film are masked The phase shift film 12 is etched to form the patterns 12a, 12b, and 12c of the phase shift film.

As the etching of the phase shift film 12, a wet etching method or a dry etching method is used. However, a wet etching method in which a high etching selectivity ratio can be obtained can be preferably used because the phase shift film 12 is selectively etched with respect to the etching stopper film.

For example, when the etching stopper film 13 is a Ti-based film, the phase shift film 12 is a Cr oxide film, and a Cr oxynitride film, a cerium-based etching solution For example, a cerous ammonium nitrate aqueous solution can be preferably used, but is not limited thereto.

The first photoresist pattern 14a may be removed by an ashing method or the like after the phase shift film 12 is etched to form the patterns 12a, 12b, and 12c of the phase shift film.

In this case, the etching process of the etching stopper film 13 and the etching process of the phase shift film 12 may be performed continuously.

2 (B), a semi-permeable film 15 such as a Cr, Cr oxide film, or Cr oxynitride film with a film thickness of 1 to 40 [nm], for example, is formed as a halftone film by a sputtering method Thereafter, a second photoresist film 16 is formed on the transflective film 15 by a coating method.

Here, the light transmittance of the transflective film 15 is set to 10 to 60%, typically 20% to 55%. The transflective film 15 does not invert the phase of the exposure light and the phase shift angle is, for example, 0.4 to 15 degrees. The optical characteristics of the transflective film can be adjusted by the film thickness and the composition.

Here, the light transmittance of the transflective film, which is a halftone film, is determined depending on the purpose of use, the specification of the customer, and the like. Therefore, by providing the photomask blanks in which the phase shift film and the etching stopper film are laminated in advance, and forming the halftone film in accordance with the specification of the customer or the like, the manufacturing period from the specification of the photomask to the completion of the photomask can be shortened.

Next, as shown in Fig. 2 (C), the second photoresist film 16 is exposed and developed to form a second photoresist pattern 16a.

2 (D), the semi-transparent film 15 is etched using the second photoresist pattern 16a as a mask to form a semi-transparent film pattern 15a, The second photoresist pattern 16a is removed.

As the etching method of the semi-permeable film 15, a wet etching method or a dry etching method can be used, but a wet etching method capable of obtaining a high etching selection ratio can be preferably used.

When a Cr-based film is used as the semi-transmissive film 15 in the same manner as the phase shift film 12, for example, a ceric ammonium nitrate aqueous solution can be used as an etching solution.

Next, as shown in Fig. 3, the patterns 13a, 13b, and 13c of the etching stopper film on the patterns 12a, 12b, and 12c of the phase shift film are etched by using the pattern 15a of the transflective film as a mask. At the bottom of the pattern 15a of the semi-permeable membrane, patterns 13d and 13e of some etching stopper films remain.

As the etching method, a wet etching method or a dry etching method can be used, but a wet etching method in which a high etching selection ratio can be obtained can be preferably used. As the etching solution, a mixed solution of KOH and hydrogen peroxide water may be preferably used as described above.

On the other hand, after the process of FIG. 2 (C), the semi-transparent film 15 is etched using the second photoresist pattern 16a as a mask to form a pattern 15a of the semi-transparent film, The second photoresist pattern 16a may be removed by ashing or the like after the pattern 13a of the etching stopper film on the first photoresist pattern 12a is etched.

As shown in Fig. 3, patterns 12a, 12b and 12c of a phase shift film and a pattern 15a of a transflective film are formed on the photomask, and the transparent substrate 11 is exposed in the other regions.

In Fig. 3, the phase difference between the phase shift portion formed by the patterns 12b and 12c of the phase shift film and the semi-transparent portion formed by the pattern 15a of the semi-transparent film is approximately 180 degrees, The phase shift between the phase shifting portion of the semi-transmissive portion and the semi-transmissive portion formed by the pattern 15a of the semi-transmissive portion is 180-α when the phase shift angle of the semi-transmissive film is α [degrees], but when the transmissivity of the semi- For a transmittance of 54%, α = 1.1 [degrees], which is extremely low, and the phase difference can be regarded as approximately 180 degrees. If necessary, the thickness of the phase shift film 12 and the like can be finely adjusted to easily keep the retardation within a range of 180 +/- 10 degrees. Therefore, the exposure light distribution rapidly changes even at these boundary portions. As a result, the profile of the photoresist formed on the flat panel substrate using the present photomask, for example, changes abruptly at the boundary portion.

Further, since the phase shift angle between the transparent portion where the substrate is exposed and the phase shift portion formed by the phase shift film is approximately 180 degrees, the profile of the photoresist formed by the exposure also becomes abrupt at these boundaries.

As a result, it is possible to realize a photomask capable of both halftone effect and phase shift effect.

On the other hand, as described above, the patterns 13d and 13e of the etching stopper film remain in the boundary portion between the phase shifting portion and the semi-transmitting portion. The widths of the patterns 13d and 13e of the etching stopper film remaining in the boundary portion are different from each other in the case where the alignment error of the photomask drawing apparatus (laser drawing apparatus) for exposing the second photoresist pattern 16a ). As a result, it becomes possible to adjoin the semi-transmissive portion and the phase shift portion without overlapping due to overlapping misalignment.

The width of the patterns 13d and 13e of the etching stopper film is set to a dimension within a range that does not affect the exposure results when the photoresist is exposed by the photomask pattern. That is, the widths of the patterns 13d and 13e of the etching stopper film are set to be below the resolution limit of the projection (projection) exposure apparatus that exposes the photoresist using a photomask.

With respect to the resolution limit of the projection exposure apparatus, as an empirical rule,

lambda / (2NA) can be used. Here,? Is the wavelength (representative wavelength) of the projection exposure apparatus, and NA is the numerical aperture of the projection exposure apparatus. By setting the widths of the patterns 13d and 13e of the etching stopper film to be below the resolution limit, the exposure result of the photoresist is not affected.

Specifically, by setting the width (set value) of the patterns 13d and 13e of the etching stopper film as boundary portions to the alignment error d [mu m] of the photomask drawing apparatus, the pattern of the etching stopper film 13d , And 13e) falls within the range of 0 to 2d. A typical value of d of the laser imaging apparatus is, for example, 0.5 [mu m], and the actual width of the boundary portion in the photomask is 0 to 1 [mu m].

In addition, in a projection exposure apparatus for a flat panel display widely used at present, NA is about 0.09, and the representative wavelength? Is 365 [nm]. When these values are applied to the above equations, the resolution limit becomes 2.0 [mu m]. Compared with this resolution limit, the alignment error of the laser imaging device is sufficiently small. Therefore, by setting the widths of the patterns 13d and 13e of the etching stopper film to the alignment errors of the photomask drawing apparatus, it becomes equal to or less than the resolution limit of the projection exposure apparatus of the photoresist in practical use, It is possible.

In the photomask of this embodiment, for example, the patterns 12b and 12c of the phase shift film are used for the source drain electrode of the TFT, and the pattern 15a of the semitransparent film is used for forming the pattern of the channel region of the TFT . The profile of the photoresist film at the boundary portion between the source drain region and the channel region becomes abrupt, and the edge portion of the source / drain electrode also becomes abrupt. Thus, miniaturization of the TFT can be realized.

FIG. 4 is a diagram showing a photoresist pattern exposed by a conventional photomask in which a photoresist pattern exposed according to the present embodiment in which a halftone film and a phase shift film are combined and a shielding film that does not transmit a halftone film and exposure light are combined .

Fig. 4 (a) is a cross section of the photomask of this embodiment, and Fig. 4 (a) is an enlarged view of a part of Fig. 4B is a cross-sectional view of a conventional photomask disclosed in Patent Document 1. A pattern 43 of a halftone film is formed on a transparent substrate 42 and a pattern 43 of a halftone film is formed on a pattern 43 of a halftone film. (Etching stopper film) pattern 44 and a light-shielding film pattern 45 are formed.

Fig. 4 (c) schematically shows the cross-sectional shape of the photoresist 30 exposed by the photomask shown in Fig. 4 (a). The thickness of the photoresist film at the position corresponding to the half-transparent film which is the halftone film is thinner than the thickness of the photoresist film at the position corresponding to the phase shift film, and by one photomask, Regions can be formed.

In Fig. 4 (c), a point P indicated by black dots represents a position corresponding to the boundary between the semitransparent film, which is a halftone film, and the phase shift film.

Similarly, a photoresist 40 having a different film thickness can be formed by a single exposure using a conventional photomask, and FIG. 4 (d) shows a state in which the photoresist 40 exposed by the photomask shown in FIG. 4 (b) Sectional shape of the photoresist 40 is schematically shown. A point Q indicated by black dots in Fig. 4 (d) represents a position corresponding to the boundary between the halftone film and the light-shielding film.

Fig. 4 (e) is a graph showing the inclination angles at the points P and Q of the photoresists 30 and 40, respectively. 4E, the inclination angle of the point P of the photomask according to the present embodiment is larger than the inclination angle of the point Q of the conventional photomask, The cross-sectional shape of the cross-section is sharply increased.

That is, as compared with the case where the photoresist is exposed by the conventional photomask, by exposing the photoresist by the photomask according to the present embodiment, the shape of the photoresist film is improved, and the boundary region An abrupt cross-sectional shape can be obtained.

(Embodiment 2)

In Embodiment 1, although the transflective film is formed after the phase shift film is formed on the transparent substrate, the photomask may be produced by forming a transflective film on the transparent substrate and then forming a phase shift film thereon.

Hereinafter, the manufacturing method of the photomask will be described with reference to the drawings. As the transparent substrate, the phase shift film, the semitransparent film, and the etching stopper film, the same film as in Embodiment 1 can be used.

A semi-permeable film 22 is formed as a halftone film on a transparent substrate 21 such as synthetic quartz glass by a sputtering method or the like and an etching stopper film 23 ) Is formed by a sputtering method or the like to provide a photomask blank 20.

Next, a third photoresist film 24 is formed on the etching stopper film 23 by a coating method.

Next, as shown in FIG. 5 (B), the third photoresist film 24 is exposed and developed to form a third photoresist pattern 24a.

Next, as shown in Fig. 5C, the etching stopper film 23 is etched using the third photoresist pattern 24a as a mask to form an etching stopper film pattern 23a.

Next, as shown in Fig. 6 (A), the third photoresist pattern 24a is removed by ashing or the like, and then the transflective film 22 is etched using the pattern 23a of the etching stopper film as a mask, Thereby forming a pattern 22a of the transmissive film.

After the step of FIG. 5C, the third photoresist pattern 24a may be removed by ashing or the like after the semi-permeable film 22 is etched to form the pattern 22a of the semi-permeable film . In this case, the etching process of the etching stopper film 23 and the etching process of the semi-permeable film 22 can be performed continuously. In the etching process of the etching stopper film 23, It is not necessary to secure the etch selectivity.

2 (A), etching of the transflective film 22 with the pattern 23a of the etching stopper film as a mask is effective in suppressing side etching of the two films.

6 (B), the phase shift film 25 is formed by a sputtering method or the like, and then a fourth photoresist film 26 is formed on the phase shift film 25 by a coating method .

Next, as shown in Fig. 6 (C), the fourth photoresist film 26 is exposed and developed to form the fourth photoresist patterns 26a, 26b, and 26c.

Next, as shown in Fig. 6D, the phase shift film 25 is etched using the fourth photoresist patterns 26a, 26b, and 26c as masks, and the patterns 25a, 25b, and 25c of the phase shift film are etched, And then the fourth photoresist patterns 26a, 26b, 26c are removed by ashing or the like.

7, the pattern 23a of the etching stopper film on the pattern 22a of the semi-transparent film is etched by using the patterns 25a and 25b of the phase shift film as a mask.

After the step of FIG. 6C, the phase shift film 25 is etched using the fourth photoresist pattern 26a as a mask to form the patterns 25a, 25b, and 25c of the phase shift film, The fourth photoresist pattern 26a may be removed by ashing or the like after the pattern 23a of the etching stopper film on the pattern 22a of the transmissive film is etched.

7, the phase difference between the phase shift portion formed by the patterns 25a and 25b of the phase shift film and the semi-transparent portion of the pattern 22a of the semi-transparent film is 180- alpha, but when the transmittance of the transflective film is high, for example, when the transmittance is 54%, it is extremely small at alpha = 1.1 and the phase difference can be regarded as approximately 180 [deg.]. Alternatively, if necessary, the phase difference can be easily kept within a range of 180 +/- 10 [degrees] by finely adjusting the film thickness of the phase shift film 12 or the like. For this reason, the exposure light distribution also changes abruptly at the boundary portion. As a result, for example, the profile of the photoresist formed on the flat panel substrate using the present photomask changes abruptly at the corresponding boundary portion.

Further, since the phase difference between the phase shifting portion and the transparent portion exposed to the substrate is also about 180 degrees, the exposure light distribution at the boundary portion is abruptly changed, and the profile of the photoresist formed by using the present photomask is corresponding It can be formed into a sharp shape at the boundary portion.

INDUSTRIAL APPLICABILITY The present invention can provide a photomask capable of reducing the photolithography process and realizing the miniaturization of the pattern, and its industrial applicability is very high.

10 Photomask Blanks
11 transparent substrate
12 phase shift film
12a, 12b, 12c The pattern of the phase shift film
13 Etch stopper film
13a, 13b, 13c, 13d, 13e Patterns of etching stopper films
14 A first photoresist film
14a, 14b, 14c First photoresist pattern
15 semi-permeable membrane
15a Pattern of semi-permeable membrane
16 A second photoresist film
16a Second photoresist pattern
20 Photomask Blanks
21 Transparent substrate
22 semi-permeable membrane
22a Pattern of the semi-permeable membrane
23 Etching stopper film
23a Pattern of etching stopper film
24 Third photoresist film
25 phase shift film
25a, 25b, 25c The pattern of the phase shift film
26 A fourth photoresist film
26a, 26b and 26c The fourth photoresist pattern
30 photoresist
40 photoresist
42 transparent substrate
43 Pattern of halftone film
44 Pattern of barrier film
45 Pattern of light-shielding film

Claims (9)

A transflective portion, a phase shift portion, a boundary portion, and a transparent portion on a transparent substrate,
Wherein the transparent portion comprises a portion where the transparent substrate is exposed,
Wherein the transflective portion is formed of a transflective film provided on the transparent substrate,
Wherein the phase shift portion is formed of a phase shift film provided on the transparent substrate,
Wherein the boundary portion is formed in a region where the semitransmissive portion and the phase shift portion are adjacent to each other,
Wherein a width of the boundary portion is equal to or less than a predetermined width,
Wherein the boundary portion is formed of a laminated structure film in which the phase shift film, the etching stopper film, and the semitransmissive film are formed in this order, while the etching stopper film of the semitransmissive portion, the phase shifting portion, And,
The width of the boundary portion is not more than the resolution limit of the transparent exposure apparatus in which the photomask is used
And a photomask. A transparent substrate is provided with a transflective portion, a phase shift portion, a boundary portion, and a transparent portion,
Wherein the transparent portion comprises a portion where the transparent substrate is exposed,
Wherein the transflective portion is formed of a semi-transparent film provided on the transparent substrate,
Wherein the phase shift portion is formed of a phase shift film provided on the transparent substrate,
Wherein the boundary portion is formed in a region where the semitransmissive portion and the phase shift portion are adjacent to each other,
Wherein a width of the boundary portion is equal to or less than a predetermined width,
Wherein the boundary portion is formed with the semitransmissive film, the etching stopper film, and the phase shift film in this order, while the etching stopper film of the semitransmissive portion, the phase shifting portion, and the transmissive portion except for the boundary portion is removed,
The width of the boundary portion is not more than the resolution limit of the projection exposure apparatus in which the photomask is used
And a photomask. 3. The method according to claim 1 or 2,
The phase shift film preferably has a transmittance of 1 to 10 [%] with respect to the exposure light and a phase of the exposure light reversed
And a photomask. 4. The method according to any one of claims 1 to 3,
The transmittance of the semi-transmissive film to the exposure light is 10 to 60%
And a photomask. 5. The method according to any one of claims 1 to 4,
The phase shift film and the semitransparent film can be etched by the same etching liquid,
The etching stopper film may have an etching selectivity to the etching solution
And a photomask. 6. The method of claim 5,
The etching stopper film is formed of a Ti-based film, and the phase shift film is formed of a Cr oxide film
And a photomask. A photomask blank for producing the photomask according to claim 1,
The phase shift film and the etching stopper film stacked in this order on the transparent substrate
/ RTI > A step of laminating a phase shift film and an etching stopper film on a transparent substrate in this order;
A step of forming a first photoresist film,
A step of patterning the first photoresist film;
Etching the etching stopper film using the first photoresist film as a mask,
Etching the phase shift film using the etching stopper film as a mask,
Removing the first photoresist film;
A step of forming a transflective film,
A step of forming a second photoresist film,
Patterning the second photoresist film so that the etch stopper film and the projection exposure apparatus have a width less than a resolution limit,
Etching the semi-transparent film with the second photoresist film as a mask,
Removing the second photoresist film;
Etching the etching stopper film on the phase shift film using the transflective film as a mask to remove the etching stopper film except for the boundary portion,
2. The method of manufacturing a photomask according to claim 1, A step of laminating a semi-transparent film and an etching stopper film on a transparent substrate in this order;
A step of forming a third photoresist film,
A step of patterning the third photoresist film;
Etching the etching stopper film using the third photoresist film as a mask,
Etching the transflective film using the etching stopper film as a mask,
Removing the third photoresist film;
A step of forming a phase shift film,
A step of forming a fourth photoresist film,
Patterning the fourth photoresist film so that a width less than a resolution limit of the etch stopper film and the projection exposure apparatus overlap;
Etching the phase shift film using the fourth photoresist film as a mask,
Removing the fourth photoresist film,
Etching the etching stopper film on the transflective film with the phase shift film as a mask to remove the etching stopper film except for the boundary portion
3. The method of manufacturing a photomask according to claim 2,

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