JP2005181721A - Halftone phase shift mask - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent film reduction of photoresist of a halftone phase shift mask. <P>SOLUTION: The halftone phase shift mask is provided with a phase shift part formed by using a halftone phase shift film 1 which inverts the phase of transmitted light by 180°, and the phase shift part has a film 2 which does not make the phase of the transmitted light invert at the center part. The halftone phase shift film 1 has 4 to 20% for the light transmissivity and the film 2 has 0 to 100% for the light transmissivity. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a halftone phase shift mask. In particular, the present invention relates to a structure of a halftone phase shift mask used in an optical lithography apparatus, a manufacturing method thereof, an exposure method, and an exposure apparatus.

  FIG. 14 is a view showing a cross-sectional structure of a conventional halftone phase shift mask.

  A conventional halftone phase shift mask has a structure in which a halftone phase shift film 1 is selectively formed on a transparent substrate 3 (see Patent Document 1).

  In photolithography, when exposure is performed by applying light having a wavelength of 157 nm or more, quartz glass is generally applied as a transparent substrate material, and the size is 6 inches square and the thickness is 0.25 inches. Further, as a material of the halftone phase shift film 1, molybdenum silicide (MoSi) having a higher dry etching rate than other materials is applied, it has optical characteristics of transmittance of 4 to 20%, and a phase difference of 180. The thickness is set to be °. The thickness D of the halftone phase shift film is expressed by the following equation where λ is the exposure wavelength and n is the refractive index of the halftone phase shift film.

D = λ / 2 (n−1)
When a conventional halftone phase shift mask is applied and transferred to the photoresist using an exposure apparatus, light passing through the halftone phase shift region and diffracted light of light passing through the transmission region without the halftone phase shift film Overlap to produce strong sidelobe light. As a result, the film thickness of the photoresist is reduced. In particular, when the line pattern or the line or hole pattern is dense, the diffracted light of a plurality of transmission regions sandwiching the halftone phase shift region overlaps, so that the film thickness of the photoresist becomes significant.

  FIG. 15 shows the result of a simulation for the light intensity distribution when exposure light having a wavelength of 157 nm is used for a 100 nm isolated line pattern formed of a halftone phase shift film having a transmittance of 15%. The light transmitted through the halftone phase shift film and the diffracted light from the transmission regions on both sides sandwiching the line formed by the halftone phase shift film overlap, and a peak of intensity enhancement occurs at the center of the line.

  FIG. 16 shows a simulation of the cross-sectional shape of a photoresist when exposure light having a wavelength of 157 nm is used for a 100 nm isolated line pattern formed of a halftone phase shift film having a transmittance of 15%, as described above. This is the result obtained. The strengthening peak at the center of the line in the light intensity distribution shown in FIG. 15 is transferred, and the film thickness of the photoresist is reduced.

  FIG. 17 is a diagram showing a cross-sectional structure of a conventional halftone phase shift mask.

  A conventional halftone phase shift mask has a structure in which a halftone phase shift film 1 is selectively formed on a transparent substrate 3.

  FIG. 18 shows a result obtained by simulation of a light intensity distribution when exposure light having a wavelength of 157 nm is used for a hole pattern having a pitch of 200 nm and a diameter of 100 nm formed of a halftone phase shift film having a transmittance of 15%. It is. 18B and 18C show the cross-sectional structure and light intensity distribution of the surface cut along line AB shown in FIG. The light transmitted through the halftone phase shift film and the diffracted light from the transmission region formed by the halftone phase shift film are overlapped, and a strengthening peak is generated beside the hole pattern.

FIG. 19 shows a simulation of the photoresist shape when exposure light having a wavelength of 157 nm is used for a hole pattern having a pitch of 200 nm and a diameter of 100 nm formed of a halftone phase shift film having a transmittance of 15%, as described above. It is the result obtained by. FIG. 19A shows a cross-sectional shape of a surface cut along a line AB shown in FIG. The strengthening peak beside the hole pattern in the light intensity distribution shown in FIG. 18 is transferred, and the film thickness of the photoresist is reduced.
JP-A-4-136854

  As described above, when the conventional halftone phase shift mask is applied and transferred to the photoresist using the exposure apparatus, the light passing through the halftone phase shift region and the diffracted light of the light passing through the transmission region overlap, This causes film loss of the photoresist.

  An object of the present invention is to prevent a film loss of a photoresist in a halftone phase shift mask.

The halftone phase shift mask according to the present invention includes a phase shift portion formed using a halftone phase shift film that reverses the phase of transmitted light by 180 °,
The phase shift unit includes a phase non-inversion unit that does not invert the phase of the transmitted light at the center.

The halftone phase shift film has a light transmittance of 4 to 20%,
The phase non-inversion part is a film having a light transmittance of 0 to 100%.

The phase shift portion is formed with a predetermined pattern width,
The non-phase-inverted portion has a width of 10 to 50% with respect to the predetermined pattern width.

The halftone phase shift mask further has a hole pattern portion adjacent to the phase shift portion and having a predetermined hole width or a predetermined hole diameter,
The phase non-inversion part is arranged in a central part of the phase shift part that is separated from the end of the hole pattern part by a predetermined hole width or a distance of 10 to 100% of a predetermined hole diameter.

  The halftone phase shift film is characterized in that a material having light resistance to light in a wavelength region of 250 nm or less is used.

  The halftone phase shift film contains at least one of tantalum silicide (TaSi), zircon silicide (ZrSi), molybdenum silicide (MoSi), chromium fluoride (CrF), and silicon oxide (SiO2) as a material. It is characterized by that.

The phase non-inversion part is formed of a predetermined film,
For the predetermined film, a material having light resistance to light in a wavelength region of 250 nm or less is used.

The phase non-inversion part is formed of a predetermined film,
The predetermined film contains at least one of tantalum silicide (TaSi), zircon silicide (ZrSi), molybdenum silicide (MoSi), chromium fluoride (CrF), and silicon oxide (SiO2) as a material. Features.

  According to the present invention, the light transmitted through the halftone phase shift film having a phase of 180 ° and the light transmitted through the film having a phase of 0 ° disposed in the center are offset, and the light intensity in the center can be suppressed. . Therefore, the film thickness reduction of the photoresist can be prevented, and the shape of the photoresist after exposure can be formed into a favorable shape.

  Further, the transmittance of the halftone phase shift film can be optimized without considering the reduction of the photoresist film, and the resolution can be improved.

  Moreover, according to the present invention, in particular, the light intensity at the center of the line pattern can be suppressed.

  Further, according to the present invention, in particular, the light intensity at the center of the remaining pattern between the hole patterns can be suppressed.

Embodiment 1 FIG.
As described below, in the first embodiment, side lobes generated when exposure is performed using a halftone phase shift mask is suppressed, and the film thickness reduction of the photoresist due to the light intensity of the side lobes is significantly reduced. Improve contrast of light intensity and significantly improve photoresist resolution.

  FIG. 1 is a diagram showing a cross-sectional structure of the halftone phase shift mask in the first embodiment.

  In FIG. 1, a halftone phase shift mask 100 includes a transparent substrate 3 and a phase shift unit 10 formed on the transparent substrate 3 using a halftone phase shift film 1 that reverses the phase of transmitted light by 180 °. ing. The transparent substrate 3 has a portion where no film is formed. The phase shift unit 10 has a film 2 as a phase non-inversion unit that does not invert the phase of the transmitted light at the center. In other words, the halftone phase shift mask 100 has a phase opposite to the halftone phase shift film 1, that is, a phase of 0 °, at the center of the pattern formed by the halftone phase shift film 1 that reverses the phase of transmitted light by 180 °. The film 2 is inserted and inserted.

  The halftone phase shift film 1 uses a material having light resistance to light in a wavelength region of 250 nm or less. For example, tantalum silicide (TaSi), zircon silicide (ZrSi), and molybdenum silicide (MoSi) are used as the material. And at least one of chromium fluoride (CrF) and silicon oxide (SiO2).

  Similarly, the film 2 uses a material having light resistance to light in a wavelength region of 250 nm or less. For example, tantalum silicide (TaSi), zircon silicide (ZrSi), and molybdenum silicide (MoSi) are used as the material. It contains at least one of chromium fluoride (CrF) and silicon oxide (SiO2). Here, whether the halftone phase shift film 1 and the film 2 are the same material film or different material films, the phase can be changed by changing the film thickness. The film thickness at which a desired phase shift occurs can be derived from the refractive index of each film. Further, the halftone phase shift film 1 and the film 2 may be formed of a two-layer film of a material for changing the phase and a material for controlling the transmittance.

  The thickness D of the film 2 is expressed by the following equation, where λ is the exposure wavelength, n is the refractive index of the halftone phase shift film, and N is the integer.

D = 2N · λ / 2 (n−1)
FIG. 2 shows a shape in which a film 2 having a width of 30 nm and a phase of 0 ° having a transmittance of 15% is inserted in the center of a 100 nm isolated line pattern formed of a halftone phase shift film 1 having a transmittance of 15%. FIG. 6 is a diagram showing a result obtained by simulation for a light intensity distribution when using the halftone phase shift mask in the first embodiment arranged in the above and using exposure light having a wavelength of 157 nm.

  As shown in FIG. 2, the light transmitted through the halftone phase shift film 1 having a phase of 180 ° and the light transmitted through the film 2 having a phase of 0 ° cancel each other, and the light intensity at the center of the line is suppressed.

  FIG. 3 is a diagram showing a result of obtaining a cross-sectional shape of a photoresist by simulation using the halftone phase shift mask in the first embodiment and using exposure light having a wavelength of 157 nm.

  As shown in FIG. 3, in the center of a 100 nm isolated line pattern formed of a halftone phase shift film 1 having a transmittance of 15%, a film 2 having a transmittance of 15% with a width of 30 nm and a phase of 0 °. By using the halftone phase shift mask 100 according to the first embodiment in which the film is disposed, the film thickness of the photoresist does not occur, and a good shape is obtained. The film 2 to be arranged is not limited to the above width, and has a good shape as long as it has a width of about 10 to 50% of the pattern width formed by the halftone phase shift film 1.

  FIG. 4 is a diagram showing a focus margin improvement effect and a sidelobe suppression effect by comparison with the prior art when the halftone phase shift mask in the first embodiment is used.

  As shown in FIG. 4, compared with the conventional halftone phase shift mask, the focus margin is improved by about 20%, and the light intensity at the center of the line pattern can be suppressed to about 10%. Further, the transmittance of the film 2 having a phase of 0 ° inserted in the center of the line pattern formed by the halftone phase shift film 1 having a phase of 180 ° is in the range of 0 to 100%, and any transmittance is similarly effective. Is obtained. Here, the light transmittance of the halftone phase shift film 1 may be 4 to 20%.

  As described above, exposure using a new halftone phase shift mask suppresses side lobes, reduces photoresist film loss due to side lobe effects, and improves light intensity contrast. Resolution can be improved.

  By using the halftone phase shift mask according to the first embodiment to expose a sample serving as a base of a semiconductor device, for example, a wafer by an exposure apparatus, the film thickness reduction of the photoresist due to the influence of side lobes is reduced and the light intensity is reduced. The contrast of the photoresist can be improved, and the resolution of the photoresist can be improved.

  FIG. 5 is a diagram showing manufacturing steps of the halftone phase shift mask in the first embodiment.

  In FIG. 5, step (a) is a deposition step of depositing the halftone phase shift film 1 on the transparent substrate 3, step (b) is a deposition step of depositing the etch stop film 6, and step (c) is an electron. After applying the line resist 5, the exposure process by the electron beam 4, the process (d) is the development process, and the process (e) is the etching of the etch stop film 6 and the halftone phase shift film 1 using the electron beam resist 5 as a mask. Step, step (f) is a removal step for removing the electron beam resist 5, step (g) is a step for depositing the film 2, and step (h) is an exposure step using the electron beam 4 after applying the electron beam resist 5. Step (i) is a development step, Step (j) is an etching step of the film 2 using the electron beam resist 5 as a mask, Step (k) is a step of removing the electron beam resist 5, and Step (l) is Etch back process of film 2, process m) shows the etch stop film 6 etch-back process.

  A halftone phase shift film 1 is formed on the transparent substrate (3) by sputtering, vacuum vapor deposition or the like (step (a)), and an etch stop film 6 is formed thereon (step (b)). The etch stop film 6 requires a film having a large etching selection ratio with the halftone phase shift film 1 and the film 2, and Poly-Si or the like is effective.

  Furthermore, the electron beam resist 5 is apply | coated on it (process (c)).

  The material of the transparent substrate 3 must have a high transmittance of 80% or more at the wavelength of the exposure light to be applied. For example, quartz glass having a transmittance of 85% or more at an exposure light wavelength of 157 nm or more is effective. As the material for the halftone phase shift film 1, tantalum silicide (TaSi), zircon silicide (ZrSi), molybdenum silicide (MoSi), chromium fluoride (CrF), and silicon oxide (SiO2) are effective as described above. When the halftone phase shift film 1 is formed, the film thickness is such that a phase of 180 ° is obtained and the light transmittance is 4 to 20%.

  Next, the electron beam resist is patterned into a resist region and a non-resist region by drawing and developing processes using the electron beam 4.

  In the electron beam resist developing process, when a positive electron beam resist 5 is applied, the electron beam resist 5 is dissolved in the developer in the region irradiated with the electron beam 4, and the halftone phase shift film 1 is exposed. In the region where the electron beam is not irradiated, the electron beam resist 5 is not dissolved in the developer, so that the pattern of the electron beam resist remains (step (d)).

  Next, the etch stop film 6 is etched using the electron beam resist 5 as a mask, and then the halftone phase shift film 1 is etched using the etch stop film 6 as a hard mask (step (e)). At this time, the etching selectivity between the halftone phase shift film 1 and the transparent substrate 3 must be sufficient.

  Thereafter, the electron beam resist 5 is peeled and removed (step (f)).

  The description so far is the same as the manufacturing process of the conventional halftone phase shift mask. However, in the case of the halftone phase shift mask 100 according to the first embodiment, a line pattern having a desired width in the electron beam resist exposure step to the halftone phase shift film 1 etching step shown in steps (c) to (f). A space pattern for embedding a film 2 to be described below is formed in the center. The space width 8 is preferably 10 to 50% of the desired line width 7. Hereinafter, with respect to the halftone phase shift mask 100 according to the first embodiment, the steps after the film (2) film formation are further continued.

  As shown in the step (g), the film 2 is formed by sputtering, vacuum deposition or the like. As a material for the film 2, tantalum silicide (TaSi), zircon silicide (ZrSi), molybdenum silicide (MoSi), chromium fluoride (CrF), and silicon oxide (SiO2) are effective. At the time of film formation, the film thickness is made thicker than a film thickness that completely fills at least a space of width 8 and can obtain a phase of 0 °.

  Next, an electron beam resist 5 is applied and exposed with an electron beam (step (h)). The pattern formed by this exposure is accurately overlapped with a line with a width of 7 and a line with a width of 9 that is narrower than the line with a width of 7. At this time, the width 9 of the line pattern is preferably a width represented by the following expression.

(Width 9) = ((width 7) + (width 8)) / 2
Next, development (step (i)) is performed, and the film 2 is etched using the electron beam resist 5 as a mask. At this time, the etch stop film 6 functions as a hard mask, and the halftone phase shift film 1 remains without being etched (step (j)).

  Thereafter, the electron beam resist 5 is peeled and removed (step (k)).

  Next, the etch stop film 6 is used to etch back the entire surface, and the film 2 protruding above the etch stop film 6 is removed (step (l)). At this time, the etching selectivity between the film 2 and the transparent substrate 3 must be sufficient. Since the film thickness of the film 2 is the sum of the film thickness of the halftone phase shift film 1 and the film thickness of the etch stop film 6, the etch stop is performed in advance so that the film thickness becomes a film thickness that can obtain a phase of 0 °. When the film 6 is formed, the film thickness is set to a desired film thickness.

  Thereafter, the etch stop film 6 is removed by etching back the entire surface (step (m)), and the halftone phase shift mask 100 in the first embodiment is completed. At the time of etch back, the etching selection ratio between the etch stop film 6, the halftone phase shift film 1, the film 2 and the transparent substrate 3 must be sufficient.

  FIG. 6 is a diagram showing a cross-sectional structure (line center transmittance of 0%) of another halftone phase shift mask in the first embodiment.

  FIG. 7 is a diagram showing a cross-sectional structure (line center transmittance of 80% or more) of another halftone phase shift mask in the first embodiment.

  In FIG. 7, an extraction pattern with a thickness that does not resolve is arranged in the center of a desired pattern (here, a line pattern).

  Here, since the light transmittance of the film 2 arranged in the center of the line may be 0 to 100%, when the light transmittance is set to 0%, the film 2 is placed in the halftone phase as shown in FIG. Even if it is inserted in the center of the line formed by the shift film 1, it may be arranged in the upper layer or the lower layer as shown in FIGS. 6 (b) and 6 (c). Cr or the like is effective as a film material when the light intensity is set to 0%.

  Further, since the transparent substrate 3 has a light transmittance of 80% or more, when the light transmittance of the film 2 is set to 80% or more, as shown in FIG. An effect can be obtained by simply opening the film without placing any film in the central space of the formed line.

  As described above, when the conventional halftone phase shift mask is applied and transferred to the photoresist using the exposure apparatus, the light passing through the halftone phase shift region and the diffracted light of the light passing through the transmission region overlap each other. This causes film loss of the photoresist. However, when the halftone phase shift mask in the first embodiment is applied and transferred to the photoresist using the exposure apparatus, the light transmitted through the halftone phase shift film of 180 ° phase forming the line pattern and the center of the line The light transmitted through the film having a phase of 0 ° arranged at the offset is canceled out, and the light intensity at the center of the line is suppressed. Therefore, the film thickness of the photoresist does not occur and a good shape is obtained. Conventionally, because the film thickness of the photoresist has been reduced, a high-transmission halftone phase shift film that can further improve contrast could not be applied. However, by applying this new halftone phase shift mask, the film thickness of the photoresist can be reduced. It is possible to optimize the transmittance of the halftone phase shift film without considering the above, which leads to further improvement in resolution.

Embodiment 2. FIG.
In the first embodiment, the case of a line pattern has been described, but in the second embodiment, the case of a hole pattern will be described.

  FIG. 8 is a diagram showing a cross-sectional structure of the halftone phase shift mask in the second embodiment.

  In FIG. 8, as in the first embodiment, the halftone phase shift mask 100 is formed using the transparent substrate 3 and the halftone phase shift film 1 that inverts the phase of transmitted light by 180 ° on the transparent substrate 3. A phase shift unit 10 is provided. The transparent substrate 3 has a hole pattern portion having a predetermined hole width or a predetermined hole diameter adjacent to the phase shift portion 10 which is a portion where no film is formed. The phase shift unit 10 has a film 2 as a phase non-inversion unit that does not invert the phase of the transmitted light at the center. In other words, the halftone phase mask 100 has a phase opposite to the halftone phase shift film 1, that is, a phase of 0 °, beside the hole pattern formed by the halftone phase shift film 1 that reverses the phase of transmitted light by 180 °. The film 2 is inserted and inserted. Furthermore, in other words, the halftone phase shift mask 100 is formed on the remaining pattern portion on the side of the hole pattern formed by the halftone phase film 1 that reverses the phase of transmitted light by 180 ° on the transparent substrate. A film 2 having an opposite phase, that is, a phase of 0 ° is disposed.

  FIG. 9 shows that in a hole pattern having a transmittance of 15% and a pitch of 200 nm formed on the halftone phase shift film 1 and 100 nm square on one side, the width of 20 nm is 50 nm in the center of the remaining portion between adjacent hole patterns. Using a new halftone phase shift mask arranged in the form of inserting a film 2 having a transmittance of 0% and having a phase of 0 °, the result obtained by simulation for the light intensity distribution when exposure light having a wavelength of 157 nm is used FIG.

  FIG. 9A is a diagram showing a planar structure of a new halftone phase shift mask.

  FIG. 9B is a diagram showing a cross-sectional structure (A-B cut surface) of the novel halftone phase shift mask.

  FIG. 9C shows the light intensity distribution of the new halftone phase shift mask.

  FIGS. 9B and 9C show the cross-sectional structure and light intensity distribution of the surface cut along line AB shown in FIG. 9A. The light transmitted through the halftone phase shift film having a phase of 180 ° and the light transmitted through the film having a phase of 0 ° cancel each other, and the light intensity at the center of the remaining portion between the hole patterns is suppressed.

  FIG. 10 is a diagram showing a result of obtaining the cross-sectional shape of the photoresist by simulation using the halftone phase shift mask in the second embodiment and using exposure light having a wavelength of 157 nm.

  In addition, Fig.10 (a) is the cross-sectional shape of the surface cut | disconnected by line AB shown in FIG.10 (b). In a hole pattern having a pitch of 200 nm and a diameter of 100 nm formed by the halftone phase shift film 1 having a transmittance of 15%, a phase having a transmittance of 50% with a width of 20 nm is provided at the center of the remaining portion between adjacent hole patterns. A 0 ° membrane 2 was placed. By using the halftone phase shift mask 100 according to the second embodiment, the film thickness of the photoresist does not occur and a good shape is obtained.

  Here, it is preferable that the film 2 is disposed at the center of the phase shift portion 10 that is separated from the end of the hole pattern portion by a predetermined hole width or a distance of 10 to 100% of a predetermined hole diameter. In FIG. 9, as an example, a distance of 40% of a predetermined hole width of 100 nm from the end of the hole pattern portion (40 nm in a direction perpendicular to one side of the hole pattern portion, and two ends connected to a right angle of the hole pattern portion are connected. It is arranged at the center of the phase shift unit 10 which is 56.6 nm apart in the diagonal direction.

  FIG. 11 is a diagram showing a focus margin improvement effect and a sidelobe suppression effect when the halftone phase shift mask in the second embodiment is used.

  Compared with the conventional halftone phase shift mask, the focus margin is improved by about 5%, and the light intensity at the center of the remaining portion between the hole patterns can be suppressed to about 55 to 90%. Further, the transmittance of the film 0 having a phase of 0 ° inserted in the center of the remaining portion between the hole patterns formed by the halftone phase shift film 1 having a phase of 180 ° is effective in the range of 0 to 90%. .

  As described above, exposure using a new halftone phase shift mask suppresses side lobes, reduces photoresist film loss due to side lobe effects, and improves light intensity contrast. Resolution can be improved.

  The manufacturing process of the halftone phase shift mask in the second embodiment is the same as that in FIG. When the halftone phase shift film 1 is formed, the film thickness is such that a phase of 180 ° is obtained and the light transmittance is 4 to 20%. However, in the case of the halftone phase shift mask 100 in the second embodiment, in the electron beam resist exposure process to the halftone phase shift film 1 etching process shown in the steps (c) to (f), the desired in the first embodiment. A space pattern for embedding the film 2 described below is formed in the center of the line pattern having a width of 2 mm, whereas in the second embodiment, the process of FIG. (G) A space pattern for embedding the film 2 described below is formed. The width 8 of the space is preferably 10 to 50% of the width 7 of the remaining pattern between the desired hole patterns. The film 2 may be disposed at a distance of about 10 to 100% of the hole pattern diameter or the hole pattern width from the edge of the hole pattern formed by the halftone phase shift film 1.

  FIG. 12 is a diagram showing a cross-sectional structure of another halftone phase shift mask according to Embodiment 2 (light transmittance of film 2 is 0%).

  FIG. 13 is a diagram showing a cross-sectional structure (an optical transmittance of the film 2 of 80% or more) of another halftone phase shift mask in the first embodiment.

  In FIG. 13, a removal pattern having a thickness that does not resolve is arranged in the center of a desired pattern (here, a remaining pattern between hole patterns).

  Since the light transmittance of the film 2 disposed in the center of the remaining pattern between the hole patterns may be 0 to 90%, when the light transmittance is set to 0%, the halftone phase shift film 1 is used as shown in FIG. It may be inserted in the center of the remaining pattern between the formed hole patterns (FIG. 12A), or may be arranged in the upper layer or the lower layer (FIGS. 12B and 12C). Cr or the like is effective as a film material when the light intensity is set to 0%.

  Moreover, since the transparent substrate 3 has a light transmittance of 80% or more, when the light transmittance of the film 2 is set to 80% or more, as shown in FIG. An effect can be obtained by simply opening the film without arranging any film in the central space of the remaining pattern between the formed hole patterns.

  As described above, when the conventional halftone phase shift mask is applied and transferred to the photoresist using the exposure apparatus, the light passing through the halftone phase shift region and the diffracted light of the light passing through the transmission region are generated. Overlap, resulting in photoresist film loss.

  However, when the halftone phase shift mask in the second embodiment is applied and transferred to the photoresist using the exposure apparatus, the light transmitted through the halftone phase shift film having a phase of 180 ° forming the hole pattern and the hole pattern The light transmitted through the film having a phase of 0 ° arranged at the center of the remaining pattern is canceled out, and the light intensity at the center of the remaining pattern between the hole patterns is suppressed. Therefore, the film thickness of the photoresist does not occur and a good shape is obtained. Conventionally, since the film thickness of the photoresist is reduced, a high-transmittance halftone phase shift film capable of improving the contrast cannot be applied. However, by applying the halftone phase shift mask in the second embodiment, the photoresist This makes it possible to optimize the transmittance of the halftone phase shift film without considering the reduction of the film thickness, leading to further improvement in resolution.

  By using the halftone phase shift mask in the above embodiment for an optical lithography apparatus and an exposure apparatus, it becomes possible to optimize the transmittance of the halftone phase shift film without considering the film thickness reduction of the photoresist of the sample, This leads to further resolution improvement.

FIG. 3 is a diagram showing a cross-sectional structure of a halftone phase shift mask in the first embodiment. Implementation in which a film 2 having a width of 30 nm and a phase of 0 ° and having a transmittance of 15% is inserted in the center of a 100 nm isolated line pattern formed by the halftone phase shift film 1 having a transmittance of 15% It is a figure which shows the result calculated | required by simulation about the light intensity distribution at the time of using the halftone phase shift mask in the form 1 of this, and using the exposure light of wavelength 157nm. It is a figure which shows the result of having calculated | required the cross-sectional shape of the photoresist at the time of using the halftone phase shift mask in Embodiment 1, and using the exposure light of wavelength 157nm by simulation. It is the figure which showed the focus margin improvement effect and side lobe suppression effect by contrast with a prior art at the time of using the halftone phase shift mask in Embodiment 1. FIG. 6 is a diagram showing a manufacturing process of the halftone phase shift mask in the first embodiment. FIG. FIG. 5 is a diagram showing a cross-sectional structure (line center transmittance of 0%) of another halftone phase shift mask in the first embodiment. It is a figure which shows the cross-section (line center transmittance | permeability 80% or more) of another halftone phase shift mask in Embodiment 1. FIG. 6 is a diagram showing a cross-sectional structure of a halftone phase shift mask in a second embodiment. FIG. Uses a new halftone phase shift mask with a transmittance of 15% formed by inserting a film 2 of phase 0 ° having a transmittance of 100 nm square with a pitch of 200 nm formed by the halftone phase shift film 1 FIG. 6 is a diagram showing a result obtained by simulation for a light intensity distribution when exposure light having a wavelength of 157 nm is used. It is a figure which shows the result of having calculated | required the cross-sectional shape of the photoresist at the time of using the halftone phase shift mask in Embodiment 2, and using the exposure light of wavelength 157nm by simulation. It is the figure which showed the focus margin improvement effect and the sidelobe suppression effect at the time of using the halftone phase shift mask in Embodiment 2. FIG. FIG. 10 is a diagram showing a cross-sectional structure (light transmittance of film 2 is 0%) of another halftone phase shift mask in the second embodiment. FIG. 5 is a diagram showing a cross-sectional structure of another halftone phase shift mask in Embodiment 1 (light transmittance of film 2 is 80% or more). It is a figure which shows the cross-section of the conventional halftone phase shift mask. It is the result of having calculated | required by simulation about the light intensity distribution at the time of using the exposure light of wavelength 157nm about the 100-nm isolated line pattern formed with the halftone phase shift film | membrane which has a transmittance | permeability of 15%. Similar to the above, for a 100 nm isolated line pattern formed of a halftone phase shift film having a transmittance of 15%, the cross-sectional shape of the photoresist when exposure light having a wavelength of 157 nm is used is obtained by simulation. is there. It is a figure which shows the cross-section of the conventional halftone phase shift mask. FIG. 18 shows a result obtained by simulation of the light intensity distribution when using exposure light having a wavelength of 157 nm for a hole pattern having a pitch of 200 nm and a diameter of 100 nm formed of a halftone phase shift film having a transmittance of 15%. It is. FIG. 19 shows a simulation of the photoresist shape when exposure light having a wavelength of 157 nm is used for a hole pattern having a pitch of 200 nm and a diameter of 100 nm formed of a halftone phase shift film having a transmittance of 15%, as described above. It is the result obtained by.

Explanation of symbols

  1 halftone phase shift film, 2 film, 3 transparent substrate, 4 electron beam, 5 electron beam resist, 6 etch stop film, 7 width, 8 width, 10 phase shift part, 100 halftone phase shift mask.

Claims (8)

A phase shift portion formed using a halftone phase shift film that reverses the phase of transmitted light by 180 °,
The halftone phase shift mask, wherein the phase shift unit has a phase non-inversion unit that does not invert the phase of the transmitted light at the center. The halftone phase shift film has a light transmittance of 4 to 20%,
2. The halftone phase shift mask according to claim 1, wherein the phase non-inversion portion is a film having a light transmittance of 0 to 100%. The phase shift portion is formed with a predetermined pattern width,
2. The halftone phase shift mask according to claim 1, wherein the phase non-inversion portion has a width of 10 to 50% with respect to the predetermined pattern width. The halftone phase shift mask further has a hole pattern portion adjacent to the phase shift portion and having a predetermined hole width or a predetermined hole diameter,
The phase non-inversion part is disposed in a central part of the phase shift part that is separated from an end of the hole pattern part by a predetermined hole width or 10 to 100% of a predetermined hole diameter. Item 15. A halftone phase shift mask according to Item 1.   2. The halftone phase shift mask according to claim 1, wherein the halftone phase shift film is made of a material having light resistance to light in a wavelength region of 250 nm or less.   The halftone phase shift film contains at least one of tantalum silicide (TaSi), zircon silicide (ZrSi), molybdenum silicide (MoSi), chromium fluoride (CrF), and silicon oxide (SiO2) as a material. The halftone phase shift mask according to claim 1. The phase non-inversion part is formed of a predetermined film,
2. The halftone phase shift mask according to claim 1, wherein the predetermined film is made of a material having light resistance to light in a wavelength region of 250 nm or less. The phase non-inversion part is formed of a predetermined film,
The predetermined film contains at least one of tantalum silicide (TaSi), zircon silicide (ZrSi), molybdenum silicide (MoSi), chromium fluoride (CrF), and silicon oxide (SiO2) as a material. The halftone phase shift mask according to claim 1, wherein:

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