JP6232709B2 - Phase shift mask and resist pattern forming method using the phase shift mask - Google Patents

Description

  The present invention relates to a phase shift mask used for forming a predetermined resist pattern on a workpiece and a resist pattern forming method using the phase shift mask.

  A liquid crystal display generally includes a TFT substrate having a switching active element (thin film transistor, TFT) for driving a pixel electrode, a black matrix having a predetermined opening, and a color filter substrate having a colored layer formed in the opening. Are arranged so as to face each other and the periphery is sealed, and a liquid crystal material is sealed and filled in the gap.

  In this liquid crystal display, the TFT on the TFT substrate is a photoresist having a predetermined pattern on the thin film on the transparent substrate on which a thin film made of the constituent materials thereof (gate electrode, source electrode, drain electrode, etc.) is formed. It can be formed by forming a film and etching using the patterned photoresist film as a mask. A black matrix or the like on the color filter substrate can be formed in the same manner.

  In addition, the organic EL display has a structure in which a cathode electrode, an organic EL film, and an anode electrode are laminated in this order on a transparent substrate and sealed from above with a sealing film or the like, or an organic EL film on a TFT substrate. The common electrodes are stacked in this order, and have a structure in which they are sealed from above with a sealing film or the like.

  In this organic EL display, as in the liquid crystal display, a cathode electrode, an anode electrode, a TFT, etc. are a photoresist film having a predetermined pattern on the thin film on the transparent substrate on which a thin film made of those constituent materials is formed. And etching using the patterned photoresist film as a mask.

  As a method of forming a predetermined resist pattern on a transparent substrate in the process of manufacturing an image display device such as a liquid crystal display or an organic EL display, a photo having a light shielding portion made of metal chromium having a predetermined pattern shape is generally used. A photolithographic method is used in which the photoresist film is exposed and developed using a mask (binary mask). A transparent substrate having these electrodes, TFTs, and the like is produced by multi-faceting using a large-area transparent substrate (for example, a transparent substrate of 330 mm × 450 mm or more) in order to achieve mass production and cost reduction. Therefore, as an exposure apparatus used when a predetermined resist pattern is formed on a transparent substrate, the same size projection exposure optical system capable of exposing a large area transparent substrate in a batch or a plurality of times is used. It is usual to use a large exposure apparatus.

  The dimension of the resist pattern formed by the photolithography method as described above (for example, if the resist pattern is a line-and-space pattern, the width in the short direction of the line pattern or space pattern; that is, the line width) It depends on the resolution limit. As an exposure apparatus for manufacturing an image display apparatus, one having a resolution limit of about 3 μm is generally used. If the resolution of the conventional image display device is possible, there is no problem as long as the patterning can be performed at or above the resolution limit of the exposure device. However, in recent years, the number of pixels has been increased, and an image display device having a higher resolution has been developed. Development has been demanded, and the necessity of patterning with a dimension lower than the resolution limit of a conventional exposure apparatus for manufacturing an image display apparatus is increasing.

  Under such circumstances, an attempt has been made to use a phase shift mask used for patterning with extremely small dimensions in a manufacturing process of a semiconductor device such as an LSI as a photomask in the manufacturing process of an image display device. For example, the transparent substrate has a light-transmitting part (exposure light transmittance of 100%) and a semi-light-transmitting part (exposure light transmittance of 20 to 60%), and at least one of the light-transmitting part and the semi-light-transmitting part is A photomask having a dimension portion of less than 3 μm has been proposed (see Patent Document 1).

JP 2009-42753 A

  However, by using the photomask described in Patent Document 1 above and performing exposure and development with a conventional exposure apparatus for manufacturing an image display apparatus, the dimensions of the resist pattern to be formed can be reduced by using the exposure apparatus for manufacturing the image display apparatus. Although it can be less than the image limit, the thickness of the formed resist pattern (line pattern height) becomes thin, and the patterned photoresist film serves as an etching mask in the subsequent etching process. There is a problem that it becomes difficult.

  Further, by reducing the thickness of the resist pattern, the angle of the side wall portion of the resist pattern to be formed (in the case of a line and space resist pattern, the rising angle of the line pattern side wall portion in the direction perpendicular to the substrate surface) is increased. It gets smaller. That the angle becomes smaller means that the variation in the thickness (aspect ratio) of the resist pattern in the plane on the substrate becomes larger. As a result, there is a problem that etching with high accuracy in the subsequent etching process becomes difficult.

  Since the light by the same magnification projection exposure using the conventional exposure apparatus for manufacturing an image display apparatus has a small amount of parallel light components, the transmitted light of the light transmitting part of the photomask wraps directly under the semi-light transmitting part, The photoresist film just below the semi-transmissive portion is also irradiated. As a result, the above-described problems are considered to occur.

  On the other hand, an exposure apparatus having a reduced projection exposure optical system for manufacturing a semiconductor device such as an LSI can perform exposure with light having a large amount of parallel light components, so that the exposure apparatus for manufacturing a semiconductor device can be used. It is possible to suppress the light that has passed through the light-transmitting portion of the photomask (phase shift mask) from flowing directly under the semi-light-transmitting portion.

  However, since the exposure area in the exposure apparatus for manufacturing a semiconductor device is extremely small, if the exposure apparatus for manufacturing a semiconductor device is used for the purpose of forming a resist pattern on a large substrate used in the image display apparatus, the image display apparatus is manufactured. May cause a problem that the throughput of the system is reduced.

  In view of such problems, the present invention uses a conventional exposure apparatus for manufacturing an image display apparatus, and forms a predetermined resist pattern having a dimension less than the resolution limit of the exposure apparatus on a workpiece such as a transparent substrate. It is an object to provide a phase shift mask that can be formed with high accuracy and a resist pattern forming method using the phase shift mask.

  In order to solve the above-described problems, the present invention provides a phase shift mask used for forming a resist pattern having a design dimension less than a resolution limit of an exposure apparatus on a workpiece by exposure from the exposure apparatus. A transparent substrate, a concave or convex phase shift unit provided on the transparent substrate, which gives a predetermined phase difference to the exposure light from the exposure apparatus, and a non-phase shift adjacent to the phase shift unit And at least one of the phase shift unit and the non-phase shift unit is smaller than the resolution limit of the exposure apparatus, and the dimension of the phase shift unit and the non-phase shift Unlike the dimension of the part, one of the phase shift part and the non-phase shift part has a function in which one of the small dimensions does not expose the photoresist film on the workpiece, and the other A function of exposing a photoresist film on the workpiece is exposed, and the size of the pattern region including the phase shift portion and the non-phase shift portion on the transparent substrate is 300 mm or more on a side, There is provided a phase shift mask characterized in that a light shielding part constituted by a light shielding film having a dimension smaller than the resolution limit of the exposure apparatus is not provided in the pattern region (Invention 1).

  In the present invention, “transparent” means that the transmittance of light having a wavelength of 350 to 450 nm is 85% or more, preferably 90% or more, and particularly preferably 95% or more. In the present invention, “do not expose the photoresist film” means that the photoresist located on the optical path of the transmitted light of the phase shift mask (phase shift portion or non-phase shift portion) is not exposed, Not only light is not irradiated to the photoresist film located on the optical path of light, but also that the photoresist film is irradiated with light of an intensity (low intensity) that does not expose the photoresist. To do.

  In the said invention (invention 1), ratio of the dimension of the said phase shift part and the dimension of the said non-phase shift part is 1: 1.5-1: 5.6 or 1.5: 1-5.6: 1 is preferred (Invention 2).

  In the above inventions (Inventions 1 and 2), the sum of the dimension of the phase shift part and the dimension of the non-phase shift part adjacent to the phase shift part is not less than the resolution limit of the exposure apparatus. Preferred (Invention 3).

  In the said invention (invention 1), the dimension of the small dark area of the said phase shift part and the said non-phase shift part is in the range of 0.6 micrometer-2.75 micrometers, The said phase shift part and the said The ratio of the size of the bright region of the non-phase shift portion to the size of the dark region is such that the size of the bright region is 1.5 or more when the size of the dark region is 1. Is preferred (Invention 4).

  In the said invention (invention 1-4), you may have the light-shielding part comprised by the light-shielding film of the dimension more than the resolution limit of the said exposure apparatus in the said pattern area | region (invention 5).

  In the said invention (invention 1-5), the said recessed phase shift part may be a digging part provided in the said transparent substrate (invention 6), and the said convex phase shift part is the said You may be comprised by the permeable film provided on the transparent substrate (invention 7).

  The present invention is also a method for forming a resist pattern having a design dimension less than the resolution limit of an exposure apparatus on a workpiece, the phase according to the inventions (Inventions 1 to 7) using the exposure apparatus. A step of exposing a photoresist film provided on the workpiece through a shift mask; and a step of forming a predetermined resist pattern on the workpiece by developing the exposed photoresist film And a resist pattern forming method characterized in that (Invention 8).

  According to the present invention, using a conventional exposure apparatus for manufacturing an image display apparatus, a predetermined pattern having a dimension less than the resolution limit of the exposure apparatus is formed with high accuracy on a workpiece such as a transparent substrate. And a resist pattern forming method using the phase shift mask.

FIG. 1 is a partially cut end view showing a schematic configuration of the phase shift mask according to the first embodiment of the present invention. FIG. 2 is a graph showing the light intensity of the transmitted light in the phase shift mask according to the first embodiment of the present invention. FIG. 3 is a partial plan view showing a schematic configuration of the phase shift mask according to the first embodiment of the present invention. FIG. 4 is a flowchart showing a manufacturing process of the phase shift mask according to the first embodiment of the present invention. FIG. 5 is a flowchart showing a pattern forming method using the phase shift mask according to the first embodiment of the present invention. FIG. 6 is a partial plan view showing a specific configuration example of the phase shift mask according to the first and second embodiments of the present invention. FIG. 7 is a partially cut end view showing a schematic configuration of the phase shift mask according to the second embodiment of the present invention. FIG. 8 is a graph showing the light intensity of transmitted light in the phase shift mask according to the second embodiment of the present invention. FIG. 9 is a partial plan view showing a schematic configuration of a phase shift mask according to the second embodiment of the present invention. FIG. 10 is a flowchart showing a manufacturing process (No. 1) of the phase shift mask according to the second embodiment of the present invention. FIG. 11 is a flowchart showing a manufacturing process (No. 2) of the phase shift mask according to the second embodiment of the present invention. FIG. 12 is a flowchart showing a pattern forming method using the phase shift mask according to the second embodiment of the present invention. FIG. 13 is a diagram illustrating a dark region and a bright region of the phase shift mask in Test Example 6. FIG. 14 is a diagram illustrating the dark region and the bright region of the phase shift mask in Test Example 7.

Hereinafter, the phase shift mask of the present invention and a resist pattern forming method using the same will be described.
The phase shift mask of the present invention has two aspects. Hereinafter, each aspect will be described.

1. First Aspect A phase shift mask according to a first aspect of the present invention is used to form a resist pattern having a design dimension less than the resolution limit of an exposure apparatus on a workpiece by exposure from the exposure apparatus. A transparent substrate, a concave or convex phase shift unit that is provided on the transparent substrate and imparts a predetermined phase difference to the exposure light from the exposure apparatus, and a non-phase adjacent to the phase shift unit A shift unit, and at least one of the phase shift unit and the non-phase shift unit has a dimension less than a resolution limit of the exposure apparatus, and the dimension of the phase shift unit and the non-phase Different from the dimensions of the shift portion, one of the phase shift portion and the non-phase shift portion having a smaller size serves to prevent the photoresist film on the workpiece from being exposed, and the other is the front. A function of exposing a photoresist film on the workpiece is exposed, and the size of the pattern region including the phase shift portion and the non-phase shift portion on the transparent substrate is 300 mm or more on a side, In the pattern region, there is no light-shielding portion made of a light-shielding film having a dimension less than the resolution limit of the exposure apparatus.

  Here, “the phase shift unit gives a desired phase difference to the exposure light from the exposure apparatus” specifically means that “the phase shift unit determines the phase of the exposure light transmitted through the phase shift unit. It means “inversion with respect to the phase of the exposure light transmitted through the non-phase shift portion”. Note that “the phase shift unit inverts the phase of the exposure light transmitted through the phase shift unit with respect to the phase of the exposure light transmitted through the non-phase shift unit” will be described later in “2. Second Mode”. This will be explained in the section.

  According to the first aspect, by setting the dimensions of the phase shift portion and the dimensions of the non-phase shift portion as described above, using a conventional exposure apparatus for manufacturing an image display device, on a workpiece such as a transparent substrate, A phase shift mask capable of forming a predetermined pattern having a dimension less than the resolution limit of the exposure apparatus with high accuracy can be obtained.

  Moreover, in the phase shift mask of the first aspect, the resist pattern can be formed with better accuracy than the conventional phase shift mask including the transmission part and the semi-transmission part described above. The reason for this will be described in the section “2. Second Mode” described later.

  The phase shift mask of the first aspect has two embodiments. Hereinafter, each embodiment of the phase shift mask according to the first aspect will be described with reference to the drawings.

<First Embodiment>
[Phase shift mask]
FIG. 1 is a partially cut end view showing a schematic configuration of the phase shift mask according to the first embodiment, and FIG. 2 is a graph showing the light intensity of transmitted light in the phase shift mask according to the first embodiment. FIG. 3 is a partial plan view showing a schematic configuration of the phase shift mask according to the first embodiment.

  As shown in FIG. 1, a phase shift mask 1A according to the first embodiment is adjacent to a transparent substrate 2A, a plurality of phase shift units 3A provided on the transparent substrate 2A, and each phase shift unit 3A. In the process of manufacturing an image display device such as a liquid crystal display device or an organic EL display device, the same-size projection for the image display device is provided. Design dimensions less than the resolution limit of the exposure apparatus (preferably less than 3 μm, more preferably 1.5 μm or more and less than 3 μm, particularly preferably 1.5 to 2 μm) by exposure using a large exposure apparatus having an exposure optical system. This resist pattern is used for forming on a workpiece.

  The transparent substrate 2A is not particularly limited. For example, a transparent rigid material having no flexibility such as non-alkali glass, quartz glass, Pyrex (registered trademark) glass, synthetic quartz plate, or the like may be used. it can.

  The size of the transparent substrate 2A is the size of the substrate (TFT substrate, color filter substrate, etc.) used in the image display device to be manufactured using the phase shift mask 1A according to the first embodiment, or the image display device. Can be set as appropriate according to the exposure method (collective exposure method or divided exposure method) or the like in a large-scale exposure apparatus equipped with the same-size projection exposure optical system used in the manufacture of, for example, about 330 mm × 450 mm to 1600 mm × 1800 mm Can be set.

  In addition, the thickness of the transparent substrate 2A is not particularly limited, but it is necessary to hold the phase shift mask 1A without bending during exposure, and can be appropriately set depending on the size of the transparent substrate 2A. For example, it can set in the range of 5 mm-20 mm.

  The phase shift unit 3A is provided on the transparent substrate 2A, and is configured as a dug portion dug to a predetermined depth d. And the non-digging part adjacent to the plurality of phase shift parts 3A becomes the non-phase shift part 4A.

  In the phase shift mask 1A according to the first embodiment, the dimension X of the phase shift unit 3A is different from the dimension Y of the non-phase shift unit 4A. If the two dimensions X and Y are the same, resolution cannot be achieved even if the exposure amount from the exposure apparatus is increased, and a resist pattern cannot be formed.

  In the first embodiment, at least one of the dimension X of the phase shift unit 3A and the dimension Y of the non-phase shift unit 4A is a conventionally used 1 × projection exposure optical system for manufacturing an image display device. Is less than the resolution limit of the exposure apparatus (preferably less than 3 μm, more preferably 1.5 μm or more and less than 3 μm, particularly preferably 1.5 to 2 μm). Thereby, a resist pattern having a design dimension less than the resolution limit of the exposure apparatus can be formed.

  The phase shift unit 3A in the first embodiment has a dimension X smaller than the dimension Y of the non-phase shift unit 4A. With such a configuration, the phase shift unit 3A in the first embodiment can form a fine resist pattern that is difficult to form by a photolithography technique using a conventional binary mask or the like, and the phase shift unit 3A. Is formed on a workpiece (substrate or the like) positioned on the optical path of light (transmitted light) that passes through the film, and plays a role corresponding to a light shielding portion in a conventional binary mask or the like.

  The dimension X of the phase shift part 3A can be appropriately set according to the design dimension of the resist pattern to be formed, the exposure amount from the exposure apparatus, etc., but is preferably less than 3 μm, particularly preferably 1.0 to 2.5 μm. The light transmitted through the phase shift unit 3A is given a phase difference of approximately 180 degrees from the light transmitted through the non-phase shift unit 4A, so that the transmitted light from the phase shift unit 3A and the non-adjacent to the phase shift unit 3A. The light transmitted through the phase shift unit 4A interferes with each other. Then, the phase shift portion 3A out of the transmitted light of the phase shift mask 1A because the dimension X of the phase shift portion 3A is less than the resolution limit of the exposure apparatus and smaller than the dimension Y of the non-phase shift portion 4A. The intensity of light (irradiated light) applied to the photoresist film located on the optical path of the transmitted light of 3A can be reduced to such an extent that the photoresist is not exposed (see FIG. 2). As a result, a resist pattern having a dimension less than the resolution limit of the exposure apparatus can be formed.

  On the other hand, the dimension X of the phase shift unit 3A is not less than the resolution limit of the exposure apparatus, that is, the dimension X of the phase shift part 3A and the dimension Y of the non-phase shift part 4A are both solutions of the exposure apparatus. If the size is larger than the image limit, the transmitted light of the phase shift unit 3A is not effectively interfered by the wraparound of the transmitted light of the non-phase shift unit 4A, and the photoresist located on the optical path of the transmitted light of the phase shift unit 3A It becomes impossible to reduce the intensity of the irradiation light to the film to such an extent that the photoresist is not exposed. As a result, an undesired resist pattern is formed on the optical path of the transmitted light of the phase shift portion 3A.

  That is, the resist pattern to be formed using the phase shift mask 1A according to the first embodiment is a conventional binary mask (a photomask having a light shielding portion and an opening portion made of metal chromium or the like). For example, a resist pattern formed according to the light-shielding portion (for example, a line-and-space resist pattern is formed by a positive photoresist, a line pattern, and a space is formed by a negative photoresist. When the design dimension of the pattern is less than the resolution limit of the exposure apparatus for the image display device to be used, the phase shift portion 3A for forming the resist pattern is provided in the phase shift mask 1A according to the first embodiment. Provided. On the other hand, if the design dimension of the resist pattern is equal to or greater than the resolution limit of the exposure apparatus, the light-shielding film made of metal chromium or the like for forming the resist pattern in the phase shift mask 1A according to the first embodiment. The light-shielding part 5A comprised by these is provided.

  Note that the dimension Y of the non-phase shift part 4A provided adjacent to the phase shift part 3A is appropriately set according to the design dimension of the resist pattern to be formed, and from the dimension X of the phase shift part 3A. As long as it is larger, it may be less than the resolution limit of the exposure apparatus or may be greater than or equal to the resolution limit.

  The relationship between the dimension X of the phase shift unit 3A and the dimension Y of the non-phase shift unit 4A will be described in detail. The ratio (X: Y) of the two dimensions X and Y is 1: 1.5 to 1: 5. .6, more preferably 1: 1.8 to 1: 4, and particularly preferably 1: 1.8 to 1: 3. As the ratio of the dimensions X and Y of the phase shift portion 3A and the non-phase shift portion 4A is in the above range, as will be apparent from the examples described later, the side wall angle θ of the resist pattern to be formed (see FIG. 5). (The side wall angle θ may vary depending on the type of the photoresist, etc., but preferably 60 to 90 degrees, particularly preferably 70 to 90 degrees), and the resist pattern faithful to the design dimensions Can be formed with a relatively low exposure amount.

In the first embodiment, the sum (X + Y) of the dimension X of one phase shift unit 3A and the dimension Y of one non-phase shift unit 4A adjacent to the phase shift unit 3A is the resolution limit of the exposure apparatus. The above is preferable. If the total (X + Y) is less than the resolution limit of the exposure apparatus, it may be difficult to form a resist pattern having a favorable sidewall angle θ (see FIG. 5).
The specific total (X + Y) is appropriately determined depending on the resolution limit of the exposure apparatus used together with the phase shift mask, and is not particularly limited, but is preferably 3 μm or more, and is 3.5 μm or more. More preferably.
The upper limit of the total (X + Y) is appropriately selected according to the use of the phase shift mask and is not particularly limited. The upper limit of the total (X + Y) is, for example, preferably 17.9 μm or less, and more preferably 4.5 μm or less.
In the first embodiment, the total (X + Y) is particularly preferably about 4 μm.
This is because when the total (X + Y) is within the above-described range, the phase shift part and the non-phase shift part for obtaining a desired resist pattern can be favorably designed.
In the first embodiment, when the total (X + Y) is within the above range, the ratio (X: Y) of the dimension X of the phase shift unit 3A and the dimension Y of the non-phase shift unit 4A is set. It is preferable to make it into the numerical range mentioned above. This is because the side wall angle of the resist pattern to be formed can be made better, and a resist pattern faithful to the design dimension can be suitably formed with a relatively low exposure amount.

  This will be explained in more detail with a specific example. When an exposure apparatus having a resolution limit of 3 μm is used and a line-and-space resist pattern having a design dimension of 2 μm each for a line pattern and a space pattern is to be formed, a phase shift is performed. The dimension X of the part 3A can be set preferably in the range of 0.6 to 1.6 μm, more preferably in the range of 0.8 to 1.4 μm, and particularly preferably in the range of 1 to 1.4 μm. The dimension Y of the non-phase shift portion 4A is preferably set in the range of 2.4 to 3.4 μm, more preferably in the range of 2.6 to 3.2 μm, and particularly preferably in the range of 2.6 to 3 μm. can do.

  The digging depth d of the phase shift unit 3A may be set to such an extent that a predetermined phase difference (a phase difference of 170 to 190 degrees (approximately 180 degrees)) can be imparted to the transmitted light of the phase shift unit 3A. The thickness can be appropriately set according to the thickness of the substrate 2A, the wavelength of exposure light, the refractive index of the material constituting the transparent substrate 2A, and the like.

  In the phase shift mask 1A according to the first embodiment, the phase shift unit 3A and the non-phase shift unit 4A are provided in a pattern region 6A (see FIG. 3) on the transparent substrate 2A. The pattern region 6A is at least one region set on the transparent substrate 2A according to the resist pattern to be formed on the workpiece using the phase shift mask 1A according to the first embodiment. Regardless of the exposure method in the exposure apparatus, light is irradiated on the entire surface in at least one pattern region 6A by one exposure.

  As shown in FIG. 3, in the phase shift mask 1A according to the first embodiment, a plurality of pattern areas 6A are set on the transparent substrate 2A, but even if only one pattern area 6A is set. Good. In FIG. 3, the phase shift unit 3A, the non-phase shift unit 4A, and the light shielding unit 5A in the pattern region 6A are not shown.

The size of the pattern area 6A is the size (screen size) of the image display apparatus to be manufactured using the phase shift mask 1A according to the first embodiment, the exposure method in the exposure apparatus used and the single exposure. Although it can be appropriately set according to the possible area and the like, it is set as a substantially rectangular (or substantially square) region having a short side (one side) of 300 mm or more.
Further, a pattern for forming a configuration used for one image display apparatus may be formed in one pattern region 6A, and a pattern for forming a configuration used for a plurality of image display apparatuses is formed. May be.

  In the first embodiment, in the pattern area 6A, in addition to the phase shift unit 3A and the non-phase shift unit 4A, the light shielding composed of metal chromium or the like having a dimension equal to or larger than the resolution limit of the exposure apparatus. Although the light shielding part 5A made of a film is provided, the light shielding part made of a metal chromium or the like having a dimension less than the resolution limit of the exposure apparatus is not provided. That is, the phase shift mask 1A according to the first embodiment is a so-called chromeless phase shift mask. When the dimension of the light shielding part 5A in the pattern region 6A is less than the resolution limit of the exposure apparatus, the transmitted light of the phase shift part 3A or the non-phase shift part 4A adjacent to the light shielding part 5A is transmitted to the light shielding part 5A. It will go down and become unable to perform the light shielding function.

  By using the phase shift mask 1A according to the first embodiment, the side wall angle θ (see FIG. 5) of the resist pattern formed by exposure from the exposure apparatus can be improved (type of photoresist, etc.). The side wall angle θ may vary depending on, but is preferably 60 to 90 degrees, particularly preferably 70 to 90 degrees, for example. This means that the variation in the resist pattern formation surface of the thickness (aspect ratio) of the resist pattern formed by exposure through the phase shift mask 1A according to the first embodiment can be reduced. . Therefore, according to the phase shift mask 1A according to the first embodiment, even if a conventional large exposure apparatus for an image display apparatus is used, the resist pattern has a dimension less than the resolution limit of the exposure apparatus. A resist pattern with a small dimensional error in the formation surface can be formed.

In the phase shift mask according to the first embodiment, one of the phase shift portion and the non-phase shift portion has a function of preventing the photoresist film on the workpiece from being exposed, and the other is the workpiece. It has a function of exposing a photoresist film on the material. Therefore, in the phase shift mask according to the first embodiment, in order to obtain a desired resist pattern, the size of the dark region having a small size among the phase shift unit and the non-phase shift unit, the phase shift unit, and the non-phase shift It is necessary to adjust the size of the bright region having a large size among the portions.
In the phase shift mask according to the first embodiment, the size of the dark region having a small size in the phase shift portion and the non-phase shift portion is in the range of 0.6 μm to 2.75 μm, and the phase When the ratio of the dimension of the bright area having a large dimension of the shift part and the non-phase shift part to the dimension of the dark area is 1, the dimension of the bright area is 1.5. The above is preferable.
The details of the dark region and the bright region can be the same as the content described in the section “2. Second Mode” described later, and thus the description thereof is omitted here.

[Phase Shift Mask Manufacturing Method]
The phase shift mask 1A having the above-described configuration can be manufactured as follows. FIG. 4 is a flowchart showing a process of manufacturing the phase shift mask 1A according to the first embodiment.

  First, as shown in FIG. 4A, a transparent substrate 2A having a predetermined size is prepared, and metallic chrome having a dimension that is not less than the resolution limit (eg, 3 μm) of a conventional exposure apparatus for an image display device. A light shielding part 5A composed of a light shielding film made of is formed in the pattern region 6A (see FIG. 3) on the transparent substrate 2A.

  Next, as shown in FIG. 4B, a resist layer 7A is formed so as to cover the transparent substrate 2A (pattern region 6A) and the light shielding portion 5A thereon, as shown in FIG. 4C. Then, the resist layer 7A is drawn using a laser drawing device, an electron beam drawing device or the like to form a desired pattern. At this time, at least the dimension X of the phase shift unit 3A is less than the resolution limit of the exposure apparatus for an image display device used for exposure through the phase shift mask 1A according to the first embodiment, and the dimension of the non-phase shift unit 4A. The resist is preferably set so that the ratio of the dimensions X and Y of the phase shift portion 3A and the non-phase shift portion 4A is within a predetermined range (1: 1.5 to 1: 5.6) so as to be smaller than Y. Draw layer 7A.

  Then, as shown in FIG. 4D, the transparent substrate 2A is etched using the resist layer 7A having a predetermined pattern as an etching mask. Such an etching process may be a wet etching process using an etchant such as hydrofluoric acid, or may be a dry etching process such as reactive ion etching using a fluorine-based gas or the like. Thereby, the phase shift part 3A which consists of a dug part of the predetermined depth d is formed.

  Finally, as shown in FIG. 4E, the phase shift mask 1A according to the first embodiment can be manufactured by removing the resist layer 7A remaining on the transparent substrate 2A.

[Resist pattern formation method]
Next, a method for forming a resist pattern using the phase shift mask 1A according to the first embodiment described above will be described. FIG. 5 is a flowchart showing a resist pattern forming method according to the first embodiment.

  First, a phase shift mask 1A according to the first embodiment is prepared, and a photoresist film 12A (a positive photoresist film in the first embodiment) on a workpiece (substrate) 11A that is a resist pattern formation target. The phase shift mask 1A is disposed so that the surface of the phase shift mask 1A on which the phase shift portion 3A and the like are formed is opposed to each other with a predetermined interval (see FIG. 5A).

  The substrate 11A to which the resist pattern is to be formed can be appropriately selected according to the application and the like. For example, it is used as a TFT substrate for a liquid crystal display device, a color filter substrate, a TFT substrate for an organic EL display device, or the like. If so, a glass substrate, a plastic substrate, a synthetic resin film, or the like can be used as the substrate 11A.

  Next, the photoresist film 12A on the substrate 11A is irradiated with light from an exposure apparatus (not shown) for the image display device via the phase shift mask 1A according to the first embodiment, and the photoresist film 12A. Is exposed (see FIG. 5B). At this time, the transmitted light of the phase shift unit 3A of the phase shift mask 1A according to the first embodiment and the transmitted light of the non-phase shift unit 4A interfere with each other, thereby transmitting the light of the transmitted light of the phase shift unit 3A. The intensity of the irradiation light to the photoresist film 12A located on the road is lowered to such an intensity that the photoresist film 12A at the position is not exposed. Therefore, in the photoresist film 12A on the substrate 11A, the photoresist film 12A located on the optical path of the transmitted light of the phase shift portion 3A is not exposed, and the photo resist positioned on the optical path of the transmitted light of the non-phase shift portion 4A. Only the resist film 12A is exposed.

  Subsequently, the exposed photoresist film 12A is developed using a predetermined developer, and a resist pattern 13A obtained by removing only the photoresist film 12A located on the optical path of the transmitted light of the non-phase shift portion 4A is obtained. It is formed on the substrate 11A (see FIG. 5C).

  According to the resist pattern forming method in the first embodiment described above, the dimension X of the phase shift portion 3A in the phase shift mask 1A according to the first embodiment is at least less than the resolution limit of the exposure apparatus, And by being smaller than the dimension Y of the non-phase shift part 4A, a resist pattern having a dimension less than the resolution limit of the exposure apparatus corresponding to at least the phase shift part 3A can be formed faithfully to the design dimension.

  Further, according to the resist pattern forming method in the first embodiment, a favorable side wall angle θ (which may vary depending on the type of the photoresist, etc., preferably 60 to 90 degrees, particularly preferably 70 to 90 degrees). A resist pattern 13 </ b> A can be formed. Therefore, it is possible to form a resist pattern with a small dimensional error in the surface.

In the first embodiment, the sidewall angle θ of the resist pattern 13A, the height of 10% of the positions 13A _down and resist pattern 13A in the height from the substrate 11A side of the resist pattern 13A (thickness) (thickness) The angle of the side wall of the resist pattern 13A with respect to the resist pattern formation surface of the substrate 11A is measured at an arbitrary plurality of locations (for example, 30 locations) between 90% of the positions 13A _up and obtained as an average value by the least square method. It is what The angle of the side wall of the resist pattern 13A can be calculated based on, for example, a coordinate value at an arbitrary location on the side wall of the resist pattern 13A based on the SEM image.

  As described above, according to the resist pattern forming method in the first embodiment, the resist pattern 13A having a favorable sidewall angle θ can be formed. Therefore, the thickness (aspect ratio) of the resist pattern 13A formed on the substrate 11A can be reduced. Ratio) can be suppressed, and as a result, an etching process using the resist pattern 13A as an etching mask as a subsequent process can be performed with high accuracy.

  For example, as an example of a phase shift mask that can be used to form a resist pattern for forming a transparent electrode made of ITO on a glass substrate, a phase shift portion 3A having a pattern configuration as shown in FIG. There is a phase shift mask 1A in which the shift portion 4A and the light shielding portion 5A are provided in one pattern region 6A.

  Using a large exposure apparatus having an equal magnification projection exposure optical system for an image display apparatus, a positive photoresist film provided on an ITO film on a glass substrate is exposed through a phase shift mask 1A shown in FIG. By developing the resist pattern, a resist pattern (line pattern) corresponding to the phase shift portion 3A and a resist pattern corresponding to the light shielding portion 5A can be formed on the ITO film. Then, by subjecting the glass substrate on which the resist pattern is formed to an etching process, a transparent electrode having a dimension less than the resolution limit of the large exposure apparatus for an image display device is formed on the glass substrate with high accuracy. be able to.

  The phase shift mask 1A according to the first embodiment has a large-size projection exposure optical system for an image display apparatus capable of exposing a large area, in addition to the use of forming a transparent electrode made of ITO. The present invention can be applied to an application in which a resist pattern having a size less than the resolution limit of the exposure apparatus needs to be formed on a large-area substrate using the exposure apparatus. Such applications include, for example, formation of gate electrodes, source electrodes, drain electrodes, contact holes, etc. on TFT substrates of liquid crystal displays, etc .; a black matrix on a color filter substrate, and a plurality of layers of colored members. Examples include the formation of laminated columns (laminated spacers).

  The exposure light used in the resist pattern forming method using the phase shift mask according to the first embodiment is used for a large-scale exposure apparatus having an equal magnification projection exposure optical system for a general image display apparatus. Although it can be the same and is not particularly limited, it is preferably mixed wavelength light of g-line, h-line, and i-line. This is because by using the mixed wavelength light, the amount of exposure applied to the photoresist film can be increased, and the line tact for forming the resist pattern can be shortened. In addition, by irradiating the photoresist film with the mixed wavelength light through the phase shift mask according to the first embodiment, compared to the case of using the conventional phase shift mask having the transmission part and the semi-transmission part described above, This is because a resist pattern having a predetermined thickness and partition wall angle can be obtained.

<Second Embodiment>
[Phase shift mask]
A phase shift mask according to a second embodiment will be described with reference to the drawings.
FIG. 7 is a partially cut end view showing a schematic configuration of the phase shift mask according to the second embodiment, and FIG. 8 is a graph showing the light intensity of transmitted light in the phase shift mask according to the second embodiment. FIG. 9 is a partial plan view showing a schematic configuration of the phase shift mask according to the second embodiment.

  As shown in FIG. 7, a phase shift mask 1B according to the second embodiment is adjacent to a transparent substrate 2B, a plurality of phase shift units 3B provided on the transparent substrate 2B, and each phase shift unit 3B. And a plurality of non-phase shift units 4B provided as described above, and like the phase shift mask 1A according to the first embodiment, an image display device such as a liquid crystal display device or an organic EL display device. In the process of manufacturing, the exposure using a large exposure apparatus equipped with the same size projection exposure optical system for the image display apparatus is less than the resolution limit of the exposure apparatus (preferably less than 3 μm, more preferably 1.5 μm or more. It is used for forming a resist pattern having a dimension of less than 3 μm, particularly preferably 1.5 to 2 μm on a workpiece.

  The transparent substrate 2B is not particularly limited, and the same substrate as the transparent substrate 2A in the phase shift mask 1A according to the first embodiment can be used.

  The phase shift unit 3B is provided on the transparent substrate 2B, and is configured as a transparent film having a predetermined thickness t formed on the transparent substrate 2B. And the transparent film non-formation part (exposed part of transparent substrate 2B) adjacent to the some phase shift part 3B becomes the non-phase shift part 4B.

  The transparent film constituting the phase shift portion 3B is made of a transparent material having a transmittance of light having a wavelength of 365 nm of 80% or more, preferably 85% or more, particularly preferably 90% or more. Examples of such a transparent material include SiO, ITO, and a fluorine resin.

  The dimension X of the phase shift unit 3B and the dimension Y of the non-phase shift unit 4B are set similarly to the dimension X of the phase shift unit 3A and the dimension Y of the non-phase shift unit 4A in the phase shift mask 1A according to the first embodiment. Can be done.

  The thickness t of the phase shift unit 3B may be set to such an extent that a predetermined phase difference (a phase difference of 170 to 190 degrees (approximately 180 degrees)) can be imparted to the transmitted light of the phase shift unit 3B. The thickness can be appropriately set according to the thickness of the light, the wavelength of exposure light, the refractive index of the material constituting the transparent substrate 2B, and the like.

Of the resist pattern to be formed using the phase shift mask 1B according to the second embodiment, a conventional binary mask (a photomask having a light shielding portion made of metal chromium or the like and an opening) is shielded from light. Resist pattern formed according to the part (for example, a line pattern when a line-and-space resist pattern is to be formed with a positive photoresist, a space pattern when a resist pattern is to be formed with a negative photoresist) Is smaller than the resolution limit of the exposure apparatus for the image display device to be used, the phase shift mask 1B according to the second embodiment includes a phase shift unit 3B for forming the resist pattern. . On the other hand, if the design dimension of the resist pattern is equal to or greater than the resolution limit of the exposure apparatus, the light-shielding film made of metal chromium or the like for forming the resist pattern in the phase shift mask 1B according to the second embodiment. The light-shielding part 5B comprised by these is provided.

  In the phase shift mask 1B according to the second embodiment, the phase shift unit 3B and the non-phase shift unit 4B are provided in a pattern region 6B (see FIG. 9) on the transparent substrate 2B. The pattern region 6B is at least one region set on the transparent substrate 2B according to the resist pattern to be formed on the workpiece using the phase shift mask 1B according to the second embodiment, Regardless of the exposure method in the exposure apparatus, light is irradiated to the entire surface in at least one pattern region 6B by one exposure.

  As shown in FIG. 9, in the phase shift mask 1B according to the second embodiment, a plurality of pattern regions 6B are set on the transparent substrate 2B, but even if only one pattern region 6B is set. Good. In the phase shift mask 1B shown in FIG. 9, the phase shift unit 3B, the non-phase shift unit 4B, and the light shielding unit 5B in the pattern region 6B are not shown.

The size of the pattern area 6B is the size (screen size) of the image display device to be manufactured using the phase shift mask 1B according to the second embodiment, the exposure method in the exposure apparatus used and the single exposure. Although it can be appropriately set according to the possible area and the like, it is set as a substantially rectangular (or substantially square) region having a short side (one side) of 300 mm or more.
Further, in one pattern region 6B, a pattern for forming a configuration used for one image display device may be formed, and a pattern for forming a configuration used for a plurality of image display devices is formed. May be.

  In the second embodiment, in the pattern region 6B, in addition to the phase shift unit 3B and the non-phase shift unit 4B, a light shielding film made of metallic chrome or the like having a dimension equal to or greater than the resolution limit of the exposure apparatus. Although the light-shielding part 5B configured is provided, the light-shielding part composed of a light-shielding film made of metal chromium or the like having a dimension less than the resolution limit of the exposure apparatus is not provided. That is, the phase shift mask 1B according to the second embodiment is a so-called chromeless phase shift mask. When the dimension of the light shielding part 5B in the pattern area 6B is less than the resolution limit of the exposure apparatus, the transmitted light of the phase shift part 3B or the non-phase shift part 4B adjacent to the light shielding part 5B is transmitted to the light shielding part 5B. It will go down and become unable to perform the light shielding function.

  Further, in the phase shift mask 1B according to the second embodiment shown in FIG. 7, a transparent film made of the same material as the transparent material constituting the phase shift portion 3B and having a size slightly larger than the size of the light shielding portion 5B is obtained. The light shielding part 5B may be provided so as to completely cover (see FIG. 11F). As described above, since the light shielding portion 5B is covered with the transparent film, when the non-phase shift portion 4B is adjacent to the light shielding portion 5B, the predetermined light transmission through the boundary portion between the non-phase shift portion 4B and the light shielding portion 5B is performed. Since the contrast of the irradiation light at the boundary portion can be increased by the light having the phase difference, the edge shape of the resist pattern formed according to the light shielding portion 5B can be improved.

  By using the phase shift mask 1B according to the second embodiment, the sidewall angle θ (see FIG. 12) of the resist pattern formed by exposure from the exposure apparatus can be improved (type of photoresist, etc.) The side wall angle θ may vary depending on the angle, but is preferably 60 to 90 degrees, particularly preferably 70 to 90 degrees. This means that variation in the resist pattern formation surface of the thickness (aspect ratio) of the resist pattern formed by exposure through the phase shift mask 1B according to the second embodiment can be reduced. . Therefore, according to the phase shift mask 1B according to the second embodiment, even if a conventional large exposure apparatus for an image display apparatus is used, the resist pattern has a dimension less than the resolution limit of the exposure apparatus. A resist pattern with a small dimensional error in the formation surface can be formed.

[Phase Shift Mask Manufacturing Method 1]
The phase shift mask 1B having the above-described configuration can be manufactured as follows. FIG. 10 is a flowchart showing an example of a process for manufacturing the phase shift mask 1B according to the second embodiment.

  First, as shown in FIG. 10 (a), a transparent substrate 2B having a predetermined size is prepared, and has a dimension equal to or larger than the resolution limit (for example, 3 μm) of a conventional exposure apparatus for an image display device. A light shielding portion 5B composed of a light shielding film made of is formed in the pattern region 6B (see FIG. 9) on the transparent substrate 2B.

  Next, as shown in FIG. 10B, a resist layer 7B is formed so as to cover the transparent substrate 2B (pattern region 6B) and the light shielding portion 5B thereon, as shown in FIG. 10C. Then, the resist layer 7B is drawn using a laser drawing device, an electron beam drawing device, or the like to form a desired pattern. At this time, at least the dimension X of the phase shift unit 3B is less than the resolution limit of the exposure apparatus for an image display device used for exposure through the phase shift mask 1B according to the second embodiment, and the dimension of the non-phase shift unit 4B. The resist is preferably set so that the ratio of the dimensions X and Y of the phase shift portion 3B and the non-phase shift portion 4B is within a predetermined range (1: 1.5 to 1: 5.6) so as to be smaller than Y. Layer 7B is drawn.

  Then, as shown in FIG. 10D, a transparent film 30B made of a transparent material (ITO or the like) constituting the phase shift portion 3B is formed on the resist layer 7B having a predetermined pattern. At this time, since the thickness of the formed transparent film 30B becomes the thickness t of the phase shift portion 3B, the thickness is such that a predetermined phase difference (approximately 180 degrees) can be given to the transmitted light of the phase shift portion 3B. The transparent film 30B is formed.

  Finally, as shown in FIG. 10E, the resist layer 7B remaining on the transparent substrate 2B and the transparent film 30B on the resist layer 7B are removed, whereby the phase shift mask 1B according to the second embodiment. Can be manufactured.

[Phase Shift Mask Manufacturing Method 2]
In addition to the method shown in FIG. 10 described above, the phase shift mask 1B according to the second embodiment can also be manufactured as follows. FIG. 11 is a flowchart showing another example of the process for manufacturing the phase shift mask 1B according to the second embodiment.

  First, as shown in FIG. 11 (a), a transparent substrate 2B having a predetermined size is prepared, and has a dimension equal to or larger than the resolution limit (for example, 3 μm) of a conventional exposure apparatus for an image display device. A light shielding portion 5B composed of a light shielding film made of is formed in the pattern region 6B (see FIG. 9) on the transparent substrate 2B.

  Next, as shown in FIG. 11B, the transparent substrate 2B (pattern region 6B) and the light shielding portion 5B thereon are covered so as to be made of a transparent material (ITO or the like) constituting the phase shift portion 3B. A transparent film 30B is formed. At this time, since the thickness of the transparent film 30B formed on the transparent substrate 2B becomes the thickness t of the phase shift portion 3B, a predetermined phase difference (approximately 180 degrees) is given to the transmitted light of the phase shift portion 3B. A transparent film 30B having a thickness as obtained is formed.

  Subsequently, as shown in FIG. 11C, a resist layer 7B is formed so as to cover the transparent film 30B, and as shown in FIG. 11D, a laser drawing apparatus, an electron beam drawing apparatus or the like is used. Then, the resist layer 7B is drawn to form a desired pattern. At this time, the resist layer 7B is drawn so that the resist layer 7B at the position corresponding to the phase shift portion 3B and the resist layer 7B on the light shielding portion 5B remain. It is preferable that the resist layer 7B having a size slightly larger than the size of the light shielding portion 5B is left on the light shielding portion 5B.

  Then, as shown in FIG. 11E, the transparent film 30B is etched using the resist layer 7B having a predetermined pattern as an etching mask to form the phase shift portion 3B. Such an etching process may be a wet etching process using an etchant such as hydrofluoric acid, or may be a dry etching process such as reactive ion etching using a fluorine-based gas or the like.

  Finally, as shown in FIG. 11F, the phase shift mask 1B according to the second embodiment can be manufactured by removing the resist layer 7B remaining on the transparent film 30B.

[Resist pattern formation method]
Next, a method for forming a resist pattern using the phase shift mask 1B according to the second embodiment described above will be described. FIG. 12 is a flowchart showing a resist pattern forming method according to the second embodiment.

  First, a phase shift mask 1B according to the second embodiment is prepared, and a photoresist film 12B (a positive photoresist film in the second embodiment) on a workpiece (substrate) 11B that is a resist pattern formation target. The phase shift mask 1B is disposed so that the surface of the phase shift mask 1B provided with the phase shift portion 3B and the like is opposed to each other with a predetermined interval (see FIG. 12A).

  The substrate 11B, which is a resist pattern formation target, can be appropriately selected according to the application and the like, and is used as, for example, a TFT substrate for a liquid crystal display device, a color filter substrate, a TFT substrate for an organic EL display device, or the like. If so, a glass substrate, a plastic substrate, a synthetic resin film, or the like can be used as the substrate 11B.

  Next, the photoresist film 12B on the substrate 11B is irradiated with light from an exposure apparatus (not shown) for an image display apparatus via the phase shift mask 1B according to the second embodiment, and the photoresist film 12B is exposed (see FIG. 12B). At this time, the transmitted light of the phase shift unit 3B of the phase shift mask 1B according to the second embodiment and the transmitted light of the non-phase shift unit 4B interfere with each other, thereby transmitting the transmitted light of the phase shift unit 3B. The intensity of the irradiation light to the photoresist film 12B located on the road is reduced to a light intensity that does not expose the photoresist film 12B at the position. Therefore, in the photoresist film 12B on the substrate 11B, the photoresist film 12B located on the optical path of the transmitted light of the phase shift portion 3B is not exposed, and the photo resist positioned on the optical path of the transmitted light of the non-phase shift portion 4B. Only the resist film 12B is exposed.

  Subsequently, the exposed photoresist film 12B is developed using a predetermined developer, and a resist pattern 13B obtained by removing only the photoresist film 12B located on the optical path of the transmitted light of the non-phase shift portion 4B is obtained. It is formed on the substrate 11B (see FIG. 12C).

  According to the resist pattern forming method in the second embodiment described above, the dimension X of the phase shift portion 3B in the phase shift mask 1B according to the second embodiment is at least less than the resolution limit of the exposure apparatus, And by being smaller than the dimension Y of the non-phase shift part 4B, a resist pattern having a dimension less than the resolution limit of the exposure apparatus corresponding to at least the phase shift part 3B can be formed faithfully to the design dimension.

  Further, according to the resist pattern forming method in the second embodiment, a favorable side wall angle θ (the side wall angle θ can vary depending on the type of the photoresist, etc., but is preferably 60 to 90 degrees, particularly preferably 70. A resist pattern 13B having (˜90 degrees) can be formed. Therefore, the resist pattern 13B having a small dimensional error in the surface can be formed.

In the second embodiment, the sidewall angle θ of the resist pattern 13B, the height of the 10% position 13B _down and resist patterns 13B of height from the substrate 11B side of the resist pattern 13B (thickness) (thickness) The angle of the side wall of the resist pattern 13B with respect to the resist pattern formation surface of the substrate 11B is measured at an arbitrary plurality of locations (for example, 30 locations) between 90% of the positions 13B _up and obtained as an average value by the least square method. It is The angle of the side wall of the resist pattern 13B can be calculated based on, for example, a coordinate value at an arbitrary position on the side wall of the resist pattern 13B based on the SEM image.

  Thus, according to the resist pattern forming method in the second embodiment, since the resist pattern 13B having a favorable sidewall angle θ can be formed, the thickness of the resist pattern 13B formed on the substrate 11B. Variations in (aspect ratio) can be suppressed, and as a result, an effect that enables highly accurate etching can be achieved in an etching process using the resist pattern 13B as an etching mask as a subsequent process.

  For example, as an example of a phase shift mask that can be used to form a resist pattern for forming a transparent electrode made of ITO on a glass substrate, a phase shift portion 3B having a pattern configuration as shown in FIG. There is a phase shift mask 1B in which the shift portion 4B and the light shielding portion 5B are provided in one pattern region 6B.

  Using a large exposure apparatus having an equal magnification projection exposure optical system for an image display apparatus, a positive photoresist film provided on an ITO film on a glass substrate is exposed through a phase shift mask 1B shown in FIG. And by developing, the resist pattern (line pattern) according to the phase shift part 3B and the resist pattern according to the light-shielding part 5B can be formed on the ITO film. Then, by subjecting the glass substrate on which the resist pattern is formed to an etching process, a transparent electrode having a dimension less than the resolution limit of the large exposure apparatus for an image display device is formed on the glass substrate with high accuracy. be able to.

  The phase shift mask 1B according to the second embodiment has a large-size projection exposure optical system for an image display device capable of exposing a large area in addition to the use of forming a transparent electrode made of ITO. The present invention can be applied to an application in which a resist pattern having a size less than the resolution limit of the exposure apparatus needs to be formed on a large-area substrate using the exposure apparatus. Such applications include, for example, formation of gate electrodes, source electrodes, drain electrodes, contact holes, etc. on TFT substrates of liquid crystal displays, etc .; a black matrix on a color filter substrate, and a plurality of layers of colored members. Examples include the formation of laminated columns (laminated spacers).

  The exposure light used in the resist pattern forming method using the phase shift mask according to the second embodiment is used for a large-scale exposure apparatus having an equal magnification projection optical system for a general image display apparatus. Although it can be the same and is not particularly limited, it is preferably mixed wavelength light of g-line, h-line, and i-line. Note that the reason can be the same as that described in the above-described first embodiment, and a description thereof will be omitted.

<Phase Shift Mask of First Mode>
In the first and second embodiments described above, the dimension X of the phase shift parts 3A and 3B in the phase shift masks 1A and 1B is smaller than the dimension Y of the non-phase shift parts 4A and 4B, and the phase shift parts 3A and 3B. However, the present invention is not limited to such a mode, and the dimension Y of the non-phase shift portions 4A and 4B is the phase shift portion 3A. , 3B may be smaller than the dimension X, and the non-phase shift portions 4A, 4B may serve as light shielding portions in the conventional binary mask. In this case, at least the dimension Y of the non-phase shift sections 4A and 4B is a dimension that is less than the resolution limit of a large-scale exposure apparatus that includes an equal magnification projection exposure optical system for the image display apparatus used. The ratio of the dimensions X and Y of 3A and 3B and the non-phase shift portions 4A and 4B is preferably 1.5: 1 to 5.6: 1, more preferably 1.8: 1 to 4: 1. A ratio of 1.8: 1 to 3: 1 is particularly preferable. The dimension X of the phase shift portions 3A and 3B adjacent to the non-phase shift portions 4A and 4B is appropriately set according to the design dimension of the resist pattern to be formed, and the non-phase shift portions 4A and 4B. As long as it is larger than the dimension Y, it may be less than the resolution limit of the exposure apparatus or greater than the resolution limit.

  In the first and second embodiments described above, the light-shielding portions 5A and 5B made of a light-shielding film made of metal chromium or the like are provided in the pattern regions 6A and 6B of the phase shift masks 1A and 1B. However, the present invention is not limited to such a mode, and the design dimension of the resist pattern formed by light shielding is a solution for a large-scale exposure apparatus provided with an equal magnification projection optical system for the image display apparatus used. If it is less than the image limit, the light shielding portions 5A and 5B do not need to be provided in the pattern areas 6A and 6B, and the phase shift portions 3A and 3B (corresponding to such a resist pattern). Non-phase shift units 4A and 4B) may be provided.

  As a method of manufacturing the phase shift masks 1A and 1B according to the first and second embodiments, the phase shift is applied to the transparent substrates 2A and 2B on which the light shielding portions 5A and 5B made of a light shielding film made of metal chromium or the like are formed. The method of providing the portions 3A and 3B has been described as an example. In addition to such a mode, for example, after the phase shift portions 3A and 3B are formed on the transparent substrates 2A and 2B, the light shielding film made of metal chromium or the like is used. The light shielding portions 5A and 5B to be formed may be formed.

2. Second aspect A phase shift mask according to a second aspect of the present invention includes a transparent substrate, a concave or convex phase shift portion provided on the transparent substrate, and a non-phase shift portion adjacent to the phase shift portion. The phase shift unit reverses the phase of the exposure light transmitted through the phase shift unit with respect to the phase of the exposure light transmitted through the non-phase shift unit, and the phase shift unit and The smaller one of the non-phase shift portions is used as a dark region, and the larger one of the phase shift portion and the non-phase shift portion is used as a bright region. The dimension of the bright region is 1.5 or more when the ratio of the dimension of the bright region to the size of the dark region is 1 in the range of 6 μm to 2.75 μm. Yes, large of the phase shift mask Saga, is characterized in that it is 330 mm × 450 mm or more.

In the second aspect, “the phase shift unit reverses the phase of the exposure light transmitted through the phase shift unit with respect to the phase of the exposure light transmitted through the non-phase shift unit” is transmitted through the phase shift unit. The phase difference between the exposure light (transmitted light of the phase shift portion) and the exposure light transmitted through the non-phase shift portion (transmitted light of the non-phase shift portion) is such that both transmitted light can interfere and cancel each other. It means that the phase of the phase shift unit is adjusted so as to obtain a phase difference. More specifically, the phase of the phase shift unit is adjusted so that the phase difference between the transmitted light of the phase shift unit and the transmitted light of the non-phase shift unit is within a range of 180 ° ± 10 °. Say. In the second aspect, the phase difference described above is more preferably in the range of 180 ° ± 5 °, and particularly preferably 180 °.
Further, when the exposure light used with the phase shift mask of the second aspect is a mixed wavelength light of g-line, h-line, and i-line, the transmitted light of i-line of the phase shift unit and the i-line of the non-phase shift unit It is preferable that the phase shift unit is adjusted so that the phase difference with the transmitted light satisfies the above-described relationship.

  As a specific example of the phase shift mask of the second aspect, FIG. 1 and FIG. 7 described in the section of “1. In the second mode, in the phase shift mask 1A shown in FIG. 1, the phase shift unit 3A that is an engraved portion is used as a dark region, and the non-phase shift unit 4A is used as a bright region. Further, in the phase shift mask 1B shown in FIG. 7, the phase shift unit 3B formed of a transparent film is used as a dark region, and the non-phase shift unit 4B is used as a bright region.

  According to the second aspect, when the dimension of the dark area and the dimension of the bright area have the dimensions described above, the exposure is performed on a workpiece such as a transparent substrate using a conventional exposure apparatus for manufacturing an image display apparatus. A predetermined pattern having a dimension less than the resolution limit of the apparatus can be formed with high accuracy.

  Moreover, in the phase shift mask of the second aspect, the resist pattern can be formed with better accuracy than the conventional phase shift mask including the transmission part and the semi-transmission part described above. Hereinafter, the reason for this is not clear, but is estimated as follows.

Here, as described above, a phase shift mask having a transmissive portion and a semi-transmissive portion used in the manufacturing process of a conventional semiconductor device such as an LSI is applied to a photomask in the manufacturing process of an image display device, and a conventional image display is performed. When exposure and development are performed by an exposure apparatus for manufacturing an apparatus, the resist pattern size can be made less than the resolution limit, but the resist pattern thickness is reduced or the resist pattern side wall is small. As a result, there are problems that the resist pattern does not function as an etching mask and that etching cannot be performed with high accuracy. The reason why such a problem occurs is estimated as follows.
That is, the size of a photomask for manufacturing an image display apparatus is larger than that of a normal photomask for a semiconductor manufacturing apparatus (6-inch reticle). Further, with the recent increase in size of image display devices, photomasks for image display devices have been further increased in size. As for the difference in size between the two, specifically, the length of the diagonal line of the 6-inch reticle is 215 mm, while the photomask for the image display device is about 495 mm to 1856 mm. Therefore, the photomask for the image display device has a size of 2.3 times to 8.6 times the diagonal ratio with respect to the 6 inch reticle, and is directly related to the manufacturing cost such as the drawing time and the inspection time. The area ratio is 4.4 to 72 times.
Therefore, in the same magnification projection exposure using a conventional exposure apparatus for manufacturing an image display apparatus, a large amount of light is required to perform exposure in a short time using the above-described photomask for the image display apparatus. As light, for example, mixed wavelength light of g-line, h-line, and i-line is preferably used. Specifically, for photomasks having a pattern area of 300 mm or more on one side, or photomasks having a photomask size of 330 mm × 450 mm or more, mixed wavelength light of g, h, and i lines is preferable due to manufacturing conditions. Used.
On the other hand, in the manufacturing process of a semiconductor device, for the purpose of improving the resolution of exposure, as exposure light, for example, a single wavelength on the short wavelength side such as i-line, KrF line (248 nm), ArF line (193 nm), etc. Light, that is, light with many parallel light components is preferably used. For this reason, in the phase shift mask used in the semiconductor manufacturing process, the phase of the transmissive part and the semi-transmissive part is usually adjusted with reference to single wavelength light on the short wavelength side.
Therefore, the phase shift mask in the manufacturing process of the semiconductor device in which the phases of the transmission part and the semi-transmission part are adjusted with respect to light having a large amount of parallel components (single wavelength light on the short wavelength side) as described above is used. When applied to a photomask in the manufacturing process of an image display device that uses light (mixed wavelength light) with a small light component, the transmitted light of the transmission part of the phase shift mask is likely to sneak directly under the semi-transmission part, It is assumed that the transmitted light from the semi-transmissive portion cannot be completely canceled out, and that the exposure light that sensitizes the photoresist film is irradiated onto the photoresist film corresponding to the semi-transmissive portion. As a result, it is presumed that the thickness of the obtained resist pattern is reduced and the side wall portion of the resist pattern is reduced.

On the other hand, since the phase shift mask of the second aspect is composed of the phase shift part and the non-phase shift part having different dimensions in the dark area and the bright area, both areas have the same exposure light transmittance, The phase of transmitted light in each region is inverted. Therefore, when the above-described mixed wavelength light is irradiated to the photoresist film as exposure light through the phase shift mask of the second aspect, the transmitted light in the dark region should be larger than the transmitted light in the conventional semi-transmissive portion. Therefore, it is possible to sufficiently cancel the transmitted light (wraparound light) of the bright region that has entered the dark region, and exposure light that sensitizes the photoresist film to the photoresist film corresponding to the dark region is irradiated. It is presumed that this can be suppressed.
Details of the phase shift mask of the second aspect will be described below.

[Phase shift mask]
The phase shift mask of the second aspect uses the smaller one of the phase shift part and the non-phase shift part as a dark region, and the larger one of the phase shift part and the non-phase shift part. It is used as a bright area. Further, the dimension of the dark area and the dimension of the bright area have predetermined values.
In the case where the photoresist film on the workpiece is exposed using the phase shift mask of the second aspect to produce a resist pattern, the dark region corresponds to a region of the photoresist film that is not exposed to light. The region (the region where the photoresist film is not exposed) is the bright region, and the phase shift mask region (the region where the photoresist film is exposed) corresponding to the region exposed in the photoresist film.

The phase shift mask according to the second aspect is characterized in that the size of the dark region is in the range of 0.6 μm to 2.75 μm. The dark region usually has a dimension that is less than the resolution limit of the exposure apparatus.
Specific dimensions of the dark region are appropriately selected according to the pattern shape of the dark region, the use of the phase shift mask of the second aspect, and the like, and are not particularly limited, but are in the range of 0.8 μm to 2.5 μm. In particular, it is preferably in the range of 1.0 μm to 2.0 μm.
More specifically, when the pattern shape of the dark region is a line shape, the size (line width) of the dark region is 0.6 μm or more, in particular 0.8 μm or more, particularly 1.0 μm or more. preferable. Further, the dimension (line width) of the dark region is preferably 2.05 μm or less, more preferably 2.0 μm or less, and particularly preferably 1.9 μm or less.
Further, when the pattern shape of the dark region is a square shape, the size of the dark region (the width in the short side direction of the square) is 1.3 μm or more, particularly 1.4 μm or more, particularly 1.6 μm or more. It is preferable. The size of the dark region (the width in the short side direction of the square) is preferably 2.75 μm or less, more preferably 2.5 μm or less, and particularly preferably 2.3 μm or less.
When the size of the dark region is less than the above value, the phase-reversed light transmitted through the dark region cannot obtain a light amount sufficient to cancel the light that wraps around from the bright region, so that a good resist pattern shape can be obtained. This is because there is a possibility that it cannot be obtained.
Further, when the size of the dark region exceeds the above value, the amount of transmitted light in the dark region increases when the photoresist film is exposed using the phase shift mask of the second aspect, and the transmitted light in the dark region is reduced. This is because, since the photoresist film is exposed, the central portion of the resist pattern corresponding to the dark region may be exposed.

In the phase shift mask of the second aspect, when the ratio of the dimension of the bright area to the dimension of the dark area is 1, the dimension of the bright area is 1.5 or more. It is characterized by being.
The dimension of the bright region may be a ratio with the dimension of the dark region that is not less than the value described above, may be less than the resolution limit, or may be greater than the resolution limit. The specific dimension of the bright area can be appropriately determined according to various pattern shapes so that the ratio with the dimension of the dark area is not less than the above-described value.

The phase shift mask of the second aspect is characterized in that its size is 330 mm × 450 mm or more. When the size of the phase shift mask is equal to or larger than the above value, an image display device having a high-definition configuration can be manufactured.
In addition, the size of the second phase shift mask is appropriately selected according to the application and the like, and can be, for example, about 330 mm × 450 mm to 1600 mm × 1800 mm.

Since the transparent substrate, the phase shift unit, the non-phase shift unit, and other configurations in the phase shift mask of the second mode can be the same as the contents described in the section of “1. First mode” described above, The description here is omitted.
Further, the phase shift mask of the second aspect may have a light shielding part having a dimension less than the resolution limit of the exposure apparatus and constituted by a light shielding film such as metal chromium. As such a light shielding part, for example, it is preferably used as a correction pattern for correcting a mask pattern composed of a light area, a dark area, and a light shielding part that exceeds the resolution limit of the exposure apparatus in the phase shift mask. it can.
About the dimension of a correction pattern, a pattern shape, etc., it can select suitably according to the use of the phase shift mask of a 2nd aspect, an exposure apparatus, etc.

[Phase Shift Mask Manufacturing Method]
The method of manufacturing the phase shift mask of the second aspect can be the same as the contents of the method of manufacturing the phase shift mask described in the section “1. First aspect” described above, and thus the description thereof is omitted here. To do.

[Resist pattern formation method]
The resist pattern forming method using the phase shift mask of the second aspect is the same as the contents of the resist pattern forming method described in the above section “1. First aspect” except that the mask of the second aspect is used. Therefore, the description here is omitted.

  The embodiment described above is described for facilitating understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

  EXAMPLES Hereinafter, although an Example etc. demonstrate this invention further in detail, this invention is not restrict | limited at all by the following Example etc.

[Test Example 1]
The workpiece is processed through a phase shift mask (Example 1) having a line-and-space pattern in which phase shift portions having a size of 1 μm and non-phase shift portions having a size of 3 μm are alternately arranged in parallel. When the photoresist film on the material was exposed, the light intensity of the light (irradiated light) that was transmitted through the phase shift mask and applied to the photoresist film was obtained by simulation.

  The simulation is performed using lithography simulation software. As exposure conditions in the simulation, a large exposure machine for liquid crystal displays (resolution limit: 3.5 μm, NA: 0.083, coherent factor: 0.75) is used. The light source used was a three-wavelength mixed light source of 365 nm, 405 nm, and 436 nm. The phase shift is set such that the phase is inverted by 180 degrees with reference to the exposure light having a wavelength of 365 nm, and the transmittance of the exposure light through the phase shift mask is 100%. Further, a positive photoresist A (manufactured by AZ, product name: AZ1500) was used as the resist.

  The results are shown in Table 1. In Table 1, Average represents “arithmetic average value of irradiation light intensity to photoresist film”, Max represents “maximum value of irradiation light intensity to photoresist film”, and Min represents “maximum value of irradiation light intensity to photoresist film”. “Minimum value of irradiation light intensity” and Contrast represent “difference between Max and Min”.

  Further, a binary mask (Comparative Example 1) having the same configuration as that of Example 1 is used except that the phase shift portion is changed to a light shielding layer made of metal chrome, and the photo on the workpiece is passed through the binary mask. When the resist film was exposed, the light intensity of the irradiation light to the photoresist film was obtained by simulation in the same manner as in Example 1. The results are shown in Table 1.

  Further, a halftone phase shift mask (Comparative Example 2) having the same configuration as that of Example 1 is used except that the phase shift unit is changed to a phase shift film having a transmittance of 5% provided on the transparent substrate 2A. When the photoresist film on the workpiece was exposed through the halftone phase shift mask, the light intensity of the irradiation light to the photoresist film was obtained by simulation in the same manner as in Example 1. . The results are shown in Table 1.

  As shown in Table 1, the phase shift mask of Example 1 uses the conventional binary mask (Comparative Example 1) and halftone phase shift mask (Comparative) for the minimum value (Min) of the light intensity applied to the photoresist film. It was confirmed that it can be significantly reduced as compared with Example 2). Since the minimum value (Min) of the irradiation light intensity to the photoresist film is the intensity of the irradiation light to the photoresist film located on the optical path of the transmitted light of the phase shift portion, the phase shift mask of Example 1 is used. Accordingly, the light shielding effect by the phase shift unit can be excellent.

  In addition, the phase shift mask of Example 1 shows the difference (Contrast) between the maximum value (Max) and the minimum value (Min) of the irradiation light intensity to the photoresist film, and the conventional binary mask (Comparative Example 1) or half. It was confirmed that it can be remarkably increased as compared with the tone type phase shift mask (Comparative Example 2). Since the resolution can be improved as the difference (Contrast) is increased, it is considered that the resist pattern can be formed with high resolution according to the phase shift mask of the first embodiment.

[Test Example 2]
A resist pattern (line pattern dimension: 2 μm, space pattern dimension: 2 μm) formed by exposure through the phase shift mask of Example 1, the binary mask of Comparative Example 1, and the halftone phase shift mask of Comparative Example 2 Comparison was made by simulation of resist profiles. The results are shown in Table 2. Conditions relating to simulation (conditions relating to simulation software, exposure apparatus, phase shift, resist, etc.) are the same as in Test Example 1. The results are shown in Table 2.

  As shown in Table 2, according to the phase shift mask of Example 1, the sidewall angle of the resist pattern is compared with the conventional binary mask (Comparative Example 1) and halftone phase shift mask (Comparative Example 2). It has been confirmed that it can be significantly increased. As described above, since the side wall angle of the resist pattern formed by the phase shift mask of Example 1 is large, the resist pattern shape or the like can be changed depending on the location on the substrate during exposure with a large area in the manufacturing process of an image display device or the like. The occurrence of variations can be suppressed.

  In the line-and-space resist pattern formed using the phase shift mask of Example 1, the binary mask of Comparative Example 1, and the halftone phase shift mask of Comparative Example 2, all of the dimensions and spaces of the line pattern are used. The pattern dimension was 2 μm.

[Test Example 3]
A phase shift mask (Examples 2 to 8) having the same configuration as that of Example 1 was used except that the dimensions of the phase shift unit and the non-phase shift unit were changed as shown in Table 3. When a resist pattern having a predetermined dimension (line pattern dimension: 2 μm, space pattern dimension: 2 μm) is formed by changing the exposure conditions through the exposure via the above, comparison is performed by resist profile simulation in the same manner as in Test Example 2. did.
The results are shown in Table 3. Table 3 also shows the profile of the resist pattern formed using the phase shift mask of Example 1.

As shown in Table 3, when the ratio (X: Y) of the dimension X of the phase shift part to the dimension Y of the non-phase shift part is 1: 1.5 to 1: 5.6, a favorable side wall angle is obtained. It was confirmed that a resist pattern having θ can be formed. In particular, by setting the ratio (X: Y) to 1: 1.8 to 1: 4, it is possible to form a resist pattern having a better sidewall angle θ (Examples 1 to 4, Example 6). It was confirmed that a resist pattern having a particularly favorable side wall angle θ can be formed by setting the ratio to 1: 1.8 to 1: 3 (Examples 1 to 3).
In all of Examples 1 to 8, the exposure amount was set so that a line-and-space pattern resist pattern having a pitch dimension of 4 μm, a line pattern dimension of 2 μm, and a space pattern dimension of 2 μm was obtained.

[Test Example 4]
A phase shift mask (Example 9) having the same configuration as that of Example 1 was used except that the dimensions of the phase shift unit and the non-phase shift unit were changed as shown in Table 4, and the phase shift mask was passed through the phase shift mask. Resist patterns formed by exposure were compared by resist profile simulation in the same manner as in Test Example 2. The results are shown in Table 4. The resist pattern profile formed using the phase shift mask of Example 1 is also shown in Table 4.

  As shown in Table 4, even if the total of the dimension X of the phase shift part and the dimension Y of the non-phase shift part (X + Y) is less than the resolution limit of the exposure apparatus (3.5 μm in Test Example 4), the resist pattern (Example 9), it was confirmed that a resist pattern having a good resist angle θ can be formed when the total (X + Y) is not less than the resolution limit of the exposure apparatus. (Example 1).

[Test Example 5]
The phase shift mask of Example 1 and the binary of Comparative Example 1 were the same except that the positive photoresist A in Test Example 2 was changed to another positive photoresist B (manufactured by Tokyo Ohka Co., Ltd., product name: ip3600). Resist patterns formed by exposure through the mask and the halftone phase shift mask of Comparative Example 2 were compared by resist profile simulation. The results are shown in Table 5.

  As shown in Table 5, although the side wall angle θ of the formed resist pattern can vary depending on the type of photoresist, the comparative example is obtained by using the phase shift mask of Example 1 in any photoresist. As compared with the binary mask 1 and the halftone phase shift mask of Comparative Example 2, it was confirmed that a resist pattern having a favorable sidewall angle θ can be formed.

[Test Example 6]
A phase shift mask using a square shift (see FIG. 13) digging portion having dimensions shown in Table 6 below as a dark region and a non-phase shift portion as a bright region (Examples 10 to 10) 12, when the photoresist film on the workpiece was exposed through Reference Examples 1 to 3, the resist pattern formed by the exposure was obtained by simulation of the resist profile. Conditions relating to simulation (conditions relating to simulation software, exposure apparatus, phase shift, resist, etc.) are the same as in Test Example 1. Further, the exposure amount was changed so that the resist pattern dimensions shown in Table 6 below were obtained.
FIG. 13 is a diagram for explaining a dark region and a bright region of the phase shift mask in Test Example 6. FIG. 13 shows an example in which the dark region has a square shape of 1 (isolated square). Further, the dimension of the dark region is a distance indicated by W1 in FIG.

  As shown in Table 6, in Examples 10 to 12, it was confirmed that the side wall angle θ can be made favorable.

[Test Example 7]
A phase shift mask (Examples 13 to 13) using a phase shift portion constituted by a digging portion of a line shape (see FIG. 14) having the dimensions shown in Table 7 below as a dark region and a non-phase shift portion as a bright region. 14, when the photoresist film on the workpiece was exposed through Reference Examples 4 to 5), the resist pattern formed by the exposure was obtained by simulation of the resist profile. Conditions relating to simulation (conditions relating to simulation software, exposure apparatus, phase shift, resist, etc.) are the same as in Test Example 1. The exposure amount was changed so that the resist pattern dimensions shown in Table 7 below were obtained.
FIG. 14 is a diagram for explaining a dark region and a bright region of the phase shift mask in Test Example 7. FIG. 14 shows an example in which the dark region has a line shape of 1 (isolated line). The size of the dark region is a distance indicated by W2 in FIG.

  As shown in Table 7, in Examples 13 to 14, it was confirmed that the side wall angle θ can be made favorable.

[Test Example 8]
Table 8 below shows the use of the phase shift masks of Examples 15 to 18 and Reference Example 6 in which the size of the dark area of the isolated square in Test Example 6 was changed to the size shown in Table 8 below, and the exposure amount. The exposed resist pattern was determined by resist profile simulation in the same manner as in Test Example 6 except that the dimensions of the resist pattern shown were changed so as to be obtained.
The film reduction rate in Table 8 represents the difference between the maximum thickness and the minimum thickness of the resist pattern as a ratio with respect to the maximum thickness of the resist pattern.

  As shown in Table 8, it was confirmed that the film reduction rate was larger in Reference Example 6 than in Examples 15 to 18.

[Test Example 9]
The following Table 9 shows the use of the phase shift masks of Examples 19 to 21 and Reference Example 7 in which the size of the dark region of the isolated line in Test Example 7 was changed to the size shown in Table 9 below, and the exposure amount. The exposed resist pattern was determined by resist profile simulation in the same manner as in Test Example 7 except that the dimensions of the resist pattern shown were changed.
The film reduction rate in Table 9 represents the difference between the maximum thickness and the minimum thickness of the resist pattern with respect to the maximum thickness of the resist pattern as a ratio.

  As shown in Table 9, it was confirmed that the film reduction rate was larger in Reference Example 7 than in Examples 19-21.

  From Test Examples 6 to 9, in the formation of a linear resist pattern having a plurality of dimensions of 0.6 μm or more, the light shielding composed of the dark region and the bright region and the light shielding film (for example, a chromium film) in the present invention. It was confirmed that a single phase shift photomask can be used by combining the portions and the like.

  The phase shift mask of the present invention is useful for forming a resist pattern having a dimension less than the resolution limit of an exposure apparatus used in the manufacturing process of an image display apparatus such as a liquid crystal display or an organic EL display.

1A, 1B ... Phase shift masks 2A, 2B ... Transparent substrates 3A, 3B ... Phase shift portions 4A, 4B ... Non-phase shift portions 5A, 5B ... Light shielding portions 6A, 6B ... Pattern regions 11A, 11B ... Workpiece (substrate)
12A, 12B ... Photoresist films 13A, 13B ... Resist pattern

Claims (7)

Phase shift mask used for forming a resist pattern having a design dimension less than the resolution limit of the exposure apparatus on a workpiece by exposure from an exposure apparatus using mixed wavelength light of g-line, h-line, and i-line Because
A transparent substrate;
A concave or convex phase shift unit that is provided on the transparent substrate and imparts a predetermined phase difference to the exposure light from the exposure apparatus;
A non-phase shift unit adjacent to the phase shift unit,
At least one of the phase shift unit and the non-phase shift unit has a size less than the resolution limit of the exposure apparatus, and the size of the phase shift unit and the size of the non-phase shift unit are Differently
Either one of the phase shift portion and the non-phase shift portion has a function of not exposing the photoresist film on the workpiece, and the other exposes the photoresist film on the workpiece. It fulfills its function,
The dimension of the dark region having a small dimension among the phase shift part and the non-phase shift part is in a range of 0.70 μm to 2.75 μm , and the dimension of the dimension of the phase shift part and the non-phase shift part is When the ratio of the dimension of the large bright area to the dimension of the dark area is 1, the dimension of the bright area is 1.5 or more when the dimension of the dark area is 1.
The size of the pattern region including the phase shift part and the non-phase shift part on the transparent substrate is 300 mm or more on a side,
A phase shift mask characterized in that at least the pattern region is not provided with a light-shielding portion composed of a light-shielding film having a dimension smaller than the resolution limit of the exposure apparatus.   The ratio of the dimension of the phase shift part to the dimension of the non-phase shift part is 1: 1.5 to 1: 5.6 or 1.5: 1 to 5.6: 1. Item 2. The phase shift mask according to Item 1.   The sum of the dimension of the phase shift unit and the dimension of the non-phase shift unit adjacent to the phase shift unit is equal to or greater than a resolution limit of the exposure apparatus. The phase shift mask as described.   4. The phase shift mask according to claim 1, further comprising a light-shielding portion made of a light-shielding film having a dimension not less than a resolution limit of the exposure apparatus in the pattern region. .   The phase shift mask according to any one of claims 1 to 4, wherein the concave phase shift portion is a dug portion provided in the transparent substrate.   The phase shift mask according to any one of claims 1 to 5, wherein the convex phase shift portion is configured by a transmission film provided on the transparent substrate. A method of forming a resist pattern having a design dimension less than the resolution limit of an exposure apparatus on a workpiece,
Using the exposure apparatus, exposing the photoresist film provided on the workpiece with mixed wavelength light through the phase shift mask according to any one of claims 1 to 6;
And a step of forming a predetermined resist pattern on the workpiece by developing the exposed photoresist film.

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