TWI787548B - Photomask, method of manufacturing a photomask, and method of manufacturing an electronic device - Google Patents

Abstract

Object: To provide a photomask capable of carrying out high-fidelity pattern transfer by using a proximate exposure apparatus. Solution: A photomask 10 is for use in proximate exposure and has a transfer pattern obtained by patterning a transmission control film formed on a transparent substrate. The transfer pattern includes a transmission control portion obtained by forming the transmission control film on the transparent substrate and a light transmitting portion in which the transparent substrate is exposed. The transmission control portion has a phase shift amount exceeding 180 degrees with respect to exposure light for exposing the photomask.

Description

Photomask, method of manufacturing photomask, and method of manufacturing electronic component

The invention relates to a photomask, a method for manufacturing the photomask and a method for manufacturing electronic components.

In the production of electronic components such as flat panel displays and semiconductor integrated circuits, a photomask having a transfer pattern formed by patterning an optical film such as a light-shielding film on one main surface of a transparent substrate is used.

In particular, a halftone type phase shift mask is known as a mask for semiconductor integrated circuit (hereafter, LSI: Large-scale Integrated Circuit) manufacturing. In this mask, the light-shielding region in the binary mask is set to have a transmittance to such an extent that the pattern will not be transferred, and as a structure that shifts the phase of the transmitted light by 180 degrees, the resolution performance is improved (Non-Patent Document 1) .

On the other hand, in image display devices, there is also a demand for those that increase the number of pixels and have higher resolution. Therefore, attempts to use phase shift masks for the manufacture of image display devices are being made (patent Literature 1).

Also, a multi-step halftone mask used in the manufacture of flat panel displays is known. For example, the transparent substrate is equipped with a semi-permeable film pattern and a light-shielding film pattern with a transmittance of 20-50% and a phase difference of 60-90 degrees. By using such a multi-level half-tone mask, it is possible to form a photoresist pattern whose film thickness varies depending on the position with one exposure, and reduce the number of steps of lithography in the manufacturing steps of flat panel displays, thereby reducing the manufacturing process. cost. The half-tone mask for this purpose can use transparent substrates, semi-permeable films, and light-shielding films to achieve 3 gray scales. In addition, it can also realize half-tone masks with more than 4 gray scales using multiple semi-permeable films with different transmittances ( Patent Document 2). [Prior Art Literature] [Patent Document]

[Patent Document 1] Japanese Patent Laid-Open No. 2014-092727 [Patent Document 2] Japanese Patent Laid-Open No. 2018-005072 [Non-patent literature]

[Non-Patent Document 1] Isao Tabe, Yoichi Takehana, Morihisa Nomoto, "Basic Technology for Manufacture of Photomask Electronic Parts", first edition, Tokyo Denki University Press, April 20, 2011, p.245-246

[Problem to be solved by the invention]

In the manufacture of flat panel displays, there are cases where a proximity (proximity) exposure method is applied. Compared with projection exposure equipment, proximity exposure equipment is inferior to projection exposure equipment in terms of analytical performance, but there is no imaging optical system between the mask and the object to be transferred (display substrate, etc.), so the equipment configuration is simple and the equipment can be easily introduced. It is relatively easy, and the cost advantage in manufacturing is high. For this reason, the proximity exposure device is mainly used in the manufacture of black matrix or black stripes, or photosensitive spacers (PS: Photo Spacer) used in color filters (CF: Color Filter) of liquid crystal display devices. Moreover, it can also be used for the black matrix of an organic EL display device, etc.

On the other hand, due to the increase in pixel density or brightness of flat-panel displays, and the requirements for power saving, the trend of miniaturization of transfer patterns in the photomask used in the manufacturing process is also more significant. If the projection exposure method is used in the transfer of fine patterns, the resolution is more favorable, but the above-mentioned advantages of using the proximity exposure method are lost. Therefore, it is a new issue to transfer fine patterns while applying the proximity exposure method. [Technical means to solve the problem]

The first aspect of the present invention is a photomask for proximity exposure, which is provided with a transfer pattern formed by patterning a transmission control film formed on a transparent substrate, The above-mentioned transfer pattern has: a transmission control part, which has a transmission control film formed on the above-mentioned transparent substrate; and a light-transmission part, which exposes the above-mentioned transparent substrate; The light has a phase shift of more than 180 degrees.

The second aspect of the present invention is a photomask for proximity exposure, which is provided with a transfer pattern formed by patterning a transmission control film formed on a transparent substrate, and In a photomask for proximity exposure with exposure light having a wavelength within a wavelength range of 313 to 365 nm, the transfer pattern has a transmission control portion formed by forming a transmission control film on the transparent substrate , and a light-transmitting portion through which the above-mentioned transparent substrate is exposed, and the above-mentioned transmission control portion has a phase shift of more than 180 degrees relative to light having a wavelength of 365 nm.

The third aspect of the present invention is the photomask of the first or second aspect, which is used for exposing negative photosensitive materials.

The fourth aspect of the present invention is a photomask according to any one of the first to third aspects, wherein The transmittance of the said transmission control part with respect to the light of exposure is 10% or less.

The fifth aspect of the present invention is a photomask according to any one of the first to fourth aspects, wherein The transfer pattern has a linear light-transmitting portion with a width of 3 to 10 μm.

The sixth aspect of the present invention is a photomask according to any one of the first to fourth aspects, wherein The above-mentioned pattern for transfer is a negative photosensitive material on the transfer target to form a linear pattern with a width of 10 μm or less.

The seventh aspect of the present invention is a photomask according to any one of the first to sixth aspects, wherein The pattern for transfer has a repeating pattern in which the transmission control part and the light-transmitting part are regularly arranged, and the repeating pitch of the repeating pattern is 10-35 μm.

The eighth aspect of the present invention is a photomask according to any one of the first to seventh aspects, wherein The transfer pattern has a repeating pattern in which the transmission control part and the light transmission part are regularly arranged, and the transmission control part has a shape surrounded by a closed line.

The ninth aspect of the present invention is a photomask according to any one of the first to seventh aspects, wherein The transfer pattern has a repeating pattern in which the transmission control parts are regularly arranged, and the transmission control part is a quadrilateral.

The tenth aspect of the present invention is the photomask of any one of the first to ninth aspects, wherein The transmission control unit has a phase shift amount of 255 degrees or more with respect to the exposure light.

The eleventh aspect of the present invention is a photomask according to any one of the first to tenth aspects, wherein The transmission control unit has a phase shift amount of 300 degrees or more with respect to the exposure light.

The twelfth aspect of the present invention is the mask of any one of the first to eleventh aspects, wherein The transmission control unit has a phase shift amount of 330 degrees or less with respect to the exposure light.

The thirteenth aspect of the present invention is a photomask according to any one of the first to twelfth aspects, wherein The above-mentioned pattern for transfer is a pattern for black matrix or black stripe formation.

The 14th aspect of the present invention is the photomask of any one of the 1st to 13th aspects, wherein The above-mentioned pattern for transfer is characterized in that only the above-mentioned transmission control film is patterned on the above-mentioned transparent substrate.

A fifteenth aspect of the present invention is a method of manufacturing a photomask for proximity exposure, the photomask for proximity exposure having a transfer pattern formed by patterning a transmission control film formed on a transparent substrate, and the method has the following step: Prepare a photomask base with the above-mentioned transmission control film formed on the above-mentioned transparent substrate; and A patterning step, which is to pattern the above-mentioned transmission control film to form the above-mentioned transfer pattern; The pattern for transfer has a transmission control portion formed by forming the transmission control film on the transparent substrate, and a light transmission portion exposed from the transparent substrate, The transmission control unit has a transmittance of less than 10% and a phase shift amount of 180 degrees with respect to the exposure light for exposing the mask.

The sixteenth aspect of the present invention is a method of manufacturing electronic components for flat panel displays, which includes the following steps: Prepare a photomask of any one of aspects 1 to 14; and A transfer step, which is to expose the above-mentioned photomask by a proximity exposure device, and transfer the above-mentioned transfer pattern on the negative photosensitive material film formed on the transfer object; and In the transfer step described above, proximity exposure in which the proximity gap is set in the range of 50 to 200 μm is applied. [Effect of Invention]

According to the present invention, it is possible to provide a photomask for more accurately transferring a pattern for transfer of a photomask using a proximity exposure device.

When designing high-definition electronic components such as flat panel displays and increasing the density, it would be inconvenient to simply miniaturize the pattern for transfer of the photomask used to manufacture electronic components. For example, if a pattern for transfer of a black matrix with a fine pattern width (CD: Critical Dimension) is exposed using a proximity exposure method, it is easy to produce irregularities in the shape of the pattern in the transfer image, such as corners of quadrangular pixels being curved. deteriorating.

FIG. 1 shows an example of a transfer pattern 35 for forming a black matrix. The transfer pattern 35 is formed on the transparent substrate 21 (see FIG. 6 ), and has a transmission control portion 36 and a light transmission portion 37 . The light-transmitting portion 37 is a linear portion through which the surface of the transparent substrate 21 is exposed. The transmission control part 36 is a quadrangular shape with a transmission control film formed on the transparent substrate 21 , and is arranged in a matrix with the light transmission part 37 interposed therebetween. That is, the shapes surrounded by closed lines (here, a quadrangle with four corners) are regularly arranged at specific intervals in the X direction and the Y direction perpendicular to it through the transmission control part 36 through the light transmission part 37 . In addition to the case where the corners are right angles as shown in FIG. 1 , they can also include acute angles or obtuse angles as shown in the following embodiments.

However, in the conventional photomask, the region corresponding to the transmission control portion 36 is formed on the transparent substrate 21 as a light-shielding portion with a light-shielding film formed thereon, and when exposing the photomask, substantially no light is used. Exposure light shines through. In this case, as the pattern becomes finer and the CD becomes smaller, the shape of the transferred image obtained by transferring to the transfer target body 51 (see FIG. 3 ) by proximity exposure tends to deteriorate. However, the shape of the pattern 35 for transfer cannot be faithfully reflected.

As shown in FIG. 5, the previous photomask including the light-transmitting part and the light-shielding part is transferred to the negative photosensitive material (hereinafter , for convenience, the shape of the black matrix 52 obtained when the photosensitive material is also referred to as a resist). This is an example of a case where faithful pattern transfer is not performed when exposing the pattern 35 for transfer shown in FIG. 1 . Compared with Figure 1, the corners of the quadrilateral are curved, and the shape of the linear part is also changed.

The reason for this is considered to be that, during proximity exposure, diffraction of light occurs at the edge of the pattern 35 for transfer, and further, due to the gap between the photomask and the transferred body 51 (i.e., the proximity gap), the light is scattered on the transferred body 51. Creates complex interference of light. That is, there is a problem that the light intensity distribution of the transmitted light formed on the transfer target body 51 cannot faithfully reflect the transfer pattern 35 of the photomask. In particular, this tendency is remarkably observed in high-definition patterns.

On the other hand, the so-called halftone type phase shift mask, which has a specific range of light transmittance to the exposure light and shifts the phase of the exposure light by 180 degrees, replaces the light shielding film in the semiconductor device manufacturing mask mainly used for projection exposure ( LSI photomask) field application. Therefore, the possibility that the transfer pattern 35 can be more accurately transferred by using this halftone type phase shift mask as a mask for proximity exposure is considered. Therefore, the improvement of the transferability of the pattern when the phase shift film which shifted the phase of the transmitted light by 180 degrees was formed as the transmission control part 36 in FIG. 1 was considered. However, as shown in the following embodiments, the effect is not always expected.

In general, it is known that Fresnel diffraction functions in the principle of forming a transferred image by proximity exposure. FIG. 21 is a schematic diagram showing how the exposure light transmitted through the photomask 10 reaches any point on the transfer target body 51 in the proximity exposure. In Fig. 21, light waves are represented by periodic structures of solid and dashed lines. The solid line represents the peak, and the dotted line represents the trough (the peak and the trough can also be considered in reverse). It can be seen that the light passing through the slit SL (Slit) advances while being diffracted (wrapped) at the edge, and arrives at the arrival point on the transfer target body 51 with various phases.

The amplitude information U(x, y) of light in any point (x, y) of the arrival point is approximated in the following Fresnel diffraction formula (1) (J.W.Goodman, Introduction to Fourier Optics (3rd Edition), Roberts & Company Publishers (2016), p. 66-67).

In the Fresnel diffraction formula (1), ξ and η respectively represent the X coordinate and the Y coordinate on the mask 10 . That is, U(ξ, η) is the amplitude information of the light at the coordinates (ξ, η) on the mask 10 . In addition, z represents a proximity gap, λ represents a wavelength of light to be exposed, k represents a wave number, and j represents an imaginary number unit.

[number 1]

Then, the light intensity distribution of the transferred image is determined by integrating the aforementioned amplitude information U(x, y) at all positions in a specific plane on the transfer target 51 , and transferred to the transfer target 51 .

On the other hand, it is considered that when the transfer pattern 35 of the photomask 10 is subjected to proximity exposure, optimizing the phase and amplitude of the light on the transfer target 51 is essential for improving the resolution and fidelity of the formed transfer image. Sex works. In this way, the possibility of producing a more favorable light intensity distribution for the Fresnel diffraction generated in the existing binary mask is considered.

According to the study of the present inventors, when examining the above-mentioned situation, it was found that the phase shift amount (180 degrees) of the halftone type phase shift mask used in projection exposure is not necessarily optimal in proximity exposure.

Furthermore, as a result of research, it is found that when the transfer pattern 35 for proximity exposure (for example, the transmission control portion 36 in FIG. 1 ) is formed by a transmission control film having a phase shift function and the phase shift amount When the value is larger than that of the conventional halftone type phase shift mask, the shape deterioration of the transferred image obtained on the transfer target 51 can be reduced, and the fidelity of the transfer can be improved.

[Embodiment 1] The photomask 10 of the first embodiment is constituted by providing a specific transfer pattern 35 ( FIG. 1 ) on one main surface of a rectangular or square plate-shaped transparent substrate 21 ( FIG. 6 ). As the transparent substrate 21, a transparent material such as synthetic quartz is processed and the main surface is polished to be flat and smooth. As the transparent substrate 21 used for the photomask for a flat panel display, it is preferable to use one whose main surface has a side of 300 to 2000 mm and a thickness of 5 to 16 mm.

The pattern 35 for transfer which the photomask 10 has is shown in FIG. 1 as an example. The transfer pattern 35 includes: a transmission control part 36 formed by forming a transmission control film on the transparent substrate 21 ; and a light transmission part 37 for exposing the transparent substrate 21 .

Here, the transmission control unit 36 is a rectangle with a short side dimension B and a long side dimension C, and is arranged in a matrix at intervals D in the short direction and interval E in the long direction. That is, each transmission control part 36 is regularly arranged with the light-transmitting part 37 interposed therebetween, so that the pitch in the longitudinal direction (also called the long-side pitch) is Pm1 (=C+E), and the pitch in the short-side direction (also called the short pitch) is Pm1 (=C+E). Side spacing) is the repeating pattern of Pm2 (=B+D). In Embodiment 1, the pattern 35 for transfer is a pattern for the black matrix 52 (see FIG. 4 ) used in a flat panel display, and the light-transmitting portion 37 extending vertically and horizontally in FIG. 1 is transferred to the body to be transferred 51 The above negative photosensitive material becomes the black matrix 52 to be obtained. FIG. 2 is a cross-sectional explanatory view showing a state where a black matrix 52 is formed on a glass substrate 56 constituting a transfer target body 51 .

That is, the photomask 10 is a 2-gray-scale photomask that forms a part of the photosensitive material remaining and a part of the non-photosensitive material on the transfer object, and the control part 36 corresponds to the light shielding part of the previous binary photomask. .

The dimensions (CD) of each part of the transfer pattern 35 are preferably set as follows, for example. In FIG. 1, the width D of the linear light-transmitting portion 37 (also called the long-side slit) in the longitudinal direction is preferably 3≦D≦10 (μm), Even better: 3≦D≦8(μm), Further preferably: 3≦D≦6 (μm). With the above settings, a good black matrix 52 with a relatively high aperture ratio can be obtained in a flat panel display. Even in such a high-definition pattern with fine CDs, if the present invention is applied, the shape deterioration is reduced, and the effect is remarkable.

Also, the width E of the linear light-transmitting portion 37 (also referred to as a short-side slit) extending in the horizontal direction in FIG. The width of the slit D. For example, it may be 3≦E≦30 (μm).

Again, the short-side pitch (repetitive pitch) Pm2 of the repeated pattern of Fig. 1 can be set as: 10≦Pm2≦35 (μm). Better can be set as: 15≦Pm2≦35 (μm). At this level, it can be properly used for high-definition displays of about 250 ppi to 700 ppi.

On the other hand, the distance between the long sides Pm1 is preferably greater than the aforementioned Pm2. For example, it can be set to: 30≦Pm1≦105 (μm).

In addition, in the proximity exposure, the projection magnification is not set (that is, the same magnification), and the long-side pitch Pp1 and short-side pitch Pp2 on the transfer target body 51 are the same as the above-mentioned Pm1 and Pm2.

Moreover, when performing proximity exposure using the pattern 35 for transfer of this kind, it is preferable to use the proximity gap G of about 50-200 micrometers. Furthermore, according to the present invention, even when there is in-plane unevenness close to the gap G, the in-plane unevenness of the transferred image resulting therefrom is reduced. The collimation angle of close-up exposure is preferably about 1.5-2.5 degrees.

It is conceivable to form a linear pattern with a width of 10 μm or less on the transferred body 51 corresponding to the linear light-transmitting portion 37 of the above-mentioned width D using the transfer pattern 35 as described above. For example, it is conceivable to form a black matrix 52 with a width of 3 to 10 μm, and to form a pattern with a width of 3 to 8 μm, which is finer, or a width of 3 to 6 μm, to form a black matrix 52 with a finer width.

(度)之作用。即，透過控制膜之相位偏移量

為：

＞180(度)。In the photomask 10 of the first embodiment, the transmission control film for forming the transmission control part 36 has a phase shift with respect to the exposure light for exposing the photomask 10

(degree) role. That is, by controlling the phase shift of the film

for:

>180 (degrees).

＞180、即超過180度之相位偏移量，表示藉由下述(2)式而定義之相位偏移量

之範圍。(2)式中之M表示非負整數。 180＋360M＜

＜360＋360M(度)   ‥‥‥ (2)Furthermore, the so-called

>180, that is, the phase offset exceeding 180 degrees, means the phase offset defined by the following formula (2)

range. M in the formula (2) represents a non-negative integer. 180＋360M＜

＜360＋360M(degrees) ‥‥‥ (2)

之基準。Here, the so-called exposure light for exposing the photomask 10 refers to the light for exposing and transferring the pattern 35 for transfer by the proximity exposure device 50 ( FIG. 3 ). Light with a wavelength in the nm range. In the exposure light including a plurality of wavelengths, any wavelength (preferably a wavelength with an intensity peak) included in the above wavelength range can be used as the representative wavelength as the above phase shift amount

benchmark.

For example, in the case of using exposure light that includes wavelengths in the range of 313 to 365 nm, 313 nm on the short wavelength side can be used as the representative wavelength, or 334 nm, which is close to the median value of the above wavelength range, can be used as the representative wavelength. represents the wavelength. In addition, 365 nm, which is on the longest side of the above-mentioned wavelength range, can be used as a representative wavelength.

＞180。又，對於以下記載之較佳之波長範圍亦係同樣。Furthermore, when the light to be exposed includes multiple wavelengths, all wavelengths included in the above-mentioned wavelength range can be set as

>180. In addition, the same applies to the preferable wavelength range described below.

設為

＞180。進而，於使用之曝光之光之波長區域，亦可將強度最大之波長設為代表波長。於將高壓水銀燈設為曝光之光源且使用i射線、h射線、g射線之情形時，強度最大者一般而言為i射線。Therefore, for example, if the photomask 10 is used to perform proximity exposure by exposure light of a wavelength in the wavelength range of 313 to 365 nm, the wavelength of the transmission control part 36 relative to the longest wavelength side can be set to 365 nm. The light has a mask with a phase offset of more than 180 degrees. In this case, substantially, the phase shift amount of the transmission control unit 36 exceeds 180 degrees with respect to all the wavelengths in the above-mentioned wavelength range included in the exposed light. Alternatively, when the wavelength of the light to be exposed is set to include 365 to 436 nm (i-ray, h-ray, g-ray), 436 nm on the longest wavelength side can be used as a representative wavelength, and the transmission Control the phase shift of the film

set to

>180. Furthermore, in the wavelength region of the exposure light used, the wavelength with the maximum intensity can also be set as a representative wavelength. When a high-pressure mercury lamp is used as a light source for exposure and i-rays, h-rays, and g-rays are used, the i-rays with the highest intensity are generally i-rays.

所述者同樣之代表波長之透過率。Also, the transmission control film for forming the transmission control portion 36 has a transmittance T with respect to the light to be exposed. This transmittance T is a numerical value when the transparent substrate 21 is 1.0 (100%). Also, the so-called transmittance here can be set relative to and about the above-mentioned phase shift

The above also represents the transmittance of the wavelength.

The transmittance T of the permeation control film is preferably 0.1 (10%) or less. For example, the transmittance T can be set as: 0.01≦T≦0.1. If T is too small, the fidelity improvement effect described below cannot be significantly obtained for the existing binary mask. If T is too large, there is a risk that the light-shielding property will become insufficient in the area far from the edge in the transmission control unit 36 .

之詳情，於下文中進行敍述。For the transmittance T and phase shift of the transmission control film

The details are described below.

When forming the black matrix 52 of the flat panel display using the photomask 10 , in FIG. 1 , the lines corresponding to the boundary lines between pixels (pixels) constituting the flat panel display are indicated by chain lines of two dots. In this example, one pixel includes a total of three sub-pixels of red, green, and blue, and is a square whose side length is A (=Pm1). One sub-pixel is formed in each portion corresponding to the transmission control unit 36 in FIG. 1 .

When the flat panel display is a liquid crystal display, it is made by sealing liquid crystal between the color filter substrate and the TFT (Thin-Film-Transistor, Thin-Film-Transistor) substrate arranged oppositely. The black matrix 52 is formed on one side of the color filter substrate. For example, red, green, and blue color filters may be formed in portions corresponding to the transmission control unit 36 in FIG. 1 .

When the flat panel display is an organic EL (electro-luminescence, electroluminescence) display, red, green and blue organic EL light-emitting elements are formed in the portion where the transmission control unit 36 in FIG. 1 is provided.

In any case, the black matrix 52 prevents color mixing or light leakage between the sub-pixels, so that images and images displayed on the flat panel display are clear. In order to realize a high-definition flat-panel display with small pixels, high pixel density and brightness, the width of the black matrix 52 must be thinner (for example, 3-10 μm, more preferably 3-8 μm) and formed into a designed shape. .

Therefore, it is desirable to reflect the shape of the pattern 35 for transfer which the photomask 10 has as faithfully as possible (fidelity is improved) on the transferred image on the transfer target body 51 . Here, the so-called fidelity refers to the degree to which the shape of the transfer pattern 35 of the photomask 10 is maintained on the transferred body 51 , for example, at the corner of the transfer pattern 35 on the transferred body 51 When the degree of curvature in the transferred image is reduced or the degree of thickening or thinning of the linear portion of the transfer pattern 35 is reduced in the transferred image, it can be said that the fidelity is improved.

As mentioned above, the transmissive control part 36 surrounded by the closed line of the transfer pattern 35 is arrange|positioned via the linear translucent part 37. Through the transmission control part 36, the photosensitive material on the to-be-transferred body 51 is eluted by exposure and development using the photomask 10, and on the other hand, a photosensitive material containing a photosensitive material is formed in a part corresponding to the light-transmitting part 37 surrounding it. Three-dimensional structures of non-volatile materials (such as black matrix). Moreover, the photomask 10 of the present invention has an excellent effect on improving the shape fidelity of the three-dimensional structure.

Hereinafter, the case where A to E shown in FIG. 1 are the lengths shown in Table 1 will be described as an example.

[Table 1] symbol Size (μm) A 90 B twenty four C 63 D. 6 E. 27

The proximity exposure device 50 is preferably used in the exposure of the photomask 10 of the present invention. FIG. 3 is an explanatory diagram schematically illustrating the configuration of the proximity exposure device 50 . When the proximity exposure device 50 irradiates the light emitted from the light source 57 to the back surface 12 side of the mask 10 through the illumination system 58 , it passes through the front surface 11 side on which the transfer pattern is formed, and reaches the transfer target body 51 . The proximity gap G is provided between the photomask 10 and the to-be-transferred body 51. As shown in FIG.

The light source 57 may be a high-pressure mercury lamp. The high-pressure mercury lamp has strong peaks in i-rays, h-rays, and g-rays, but in the exposure of the mask 10 in Embodiment 1, it is better to use i-rays (wavelength λ=365 nm) and shorter Spectral groups on the wavelength side. For example, it is useful to use a negative resist that has a good sensitivity range to exposure light having peaks at 365 nm, 334 nm, and 313 nm.

FIG. 4 exemplifies the shape of the black matrix 52 formed on the transfer target 51 under the assumption that the transfer pattern 35 shown in FIG. 1 is faithfully transferred to the transfer target 51 . In the case of using a negative photosensitive material, white and black are reversed with respect to FIG. 1 . Here, the shape of FIG. 4 is assumed to be an ideal black matrix.

On the other hand, FIG. 5 shows that when the binary photomask having the transfer pattern 35 shown in FIG. A transfer image in the case of deterioration in shape. For example, in the conventional photomask in which the transmission control part 36 shown in FIG. 1 is used as a light shielding part, such shape deterioration tends to generate|occur|produce. In this case, the degree of fidelity (fidelity) of the transfer such as the curvature of the corner of the part corresponding to the sub-pixel is not sufficient.

者時轉印像之保真度如何變化。Therefore, by optical simulation using Fresnel diffraction, it was verified that the transmission control film used for the transmission control part 36 in the transfer pattern 35 shown in FIG. 1 has a specific transmittance T and a phase shift. quantity

How does the fidelity of the transfer image change over time.

對上述轉印像之影響。That is, when exposing the above-mentioned transfer pattern 35 by proximity exposure, the light intensity distribution of the exposed light formed on the transfer target 51 was obtained by optical simulation, and better transfer conditions were found, and research was carried out. Transmittance T and phase shift through the control film

Effects on the above-mentioned transfer image.

The transfer image formed by the photomask 10 and proximity exposure is demonstrated using FIG. 6. FIG. FIG. 6( a ) shows a schematic cross-sectional view obtained by cutting the photomask 10 along the short side direction of the transmission control part 36 . As described using FIG. 1 , B is the width of the transmission control portion 36 , and D is the width of the light transmission portion 37 . Here, the dimension D corresponding to the width of the black matrix 52 is a fine dimension of 10 μm or less.

FIG. 6( b ) shows the light intensity distribution formed on the transfer target body 51 when exposure is performed by the proximity exposure device 50 from the back side of the photomask 10 . The horizontal axis represents the position on the transfer target body 51 , and the vertical axis represents the light intensity.

The light intensity threshold Ith corresponds to the light intensity threshold when the negative photosensitive material on the transfer target 51 forms the black matrix 52 of width D by development. At this time, when considering the ideal development model in which the development behavior can be binarized into completely soluble and completely insoluble, Ith is the threshold value of the light intensity at which the negative photosensitive material is completely insoluble.

In a repetitive pattern such as a line and space pattern, which repeats light and dark alternately, generally, the quality of the transferred image is evaluated using an index called contrast. The higher the contrast value, the clearer the light intensity difference between the bright part and the dark part. Photolithography is a method of burning transfer information on the transfer target body 51 using this difference in light and shade, and therefore, it is preferable to have a contrast of a fixed value or more.

There are some methods of quantifying the contrast, but quantification using Michelson Contrast is widely used as a method focusing on the difference. When Michelson Contrast sets the light intensity of the bright part as I1 and the light intensity of the dark part as I2, it is defined as {(I1-I2)/((I1+I2)}. In the present invention, as the light intensity of the bright part The index of Ith has been defined. On the other hand, for the dark part, according to Fig. 6 (b), it can also be seen that it greatly depends on the properties of the transmission control part 36. In Fig. 6 (b), it is shown that the assumed dark part B is very dark In the case where I2 is close to 0, but in the case where the transmission control film has a significant transmittance T as described below, the dark part depends on the position on the photomask or the position on the object to be transferred. , sometimes acting with a non-negligible light intensity.

對上述光強度分佈造成之影響。Based on the above, here, the contrast Co in the first embodiment is defined by the formula (3), and the transmittance T or the phase shift amount of the transmission control unit 36 is investigated.

The effect on the above-mentioned light intensity distribution.

[number 2]

Here, Ith corresponds to the threshold value of light intensity at which the resist film on the transfer target body 51 becomes insoluble by development as described above. In addition, it is assumed that a transferred image having a width D is formed on the transferred body 51 .

T is the inherent film transmittance of the transmission control film that does not consider the phase effect of the transmission control portion 36 with respect to the exposed light, and is a value where T is set to 1 when the transmittance is 100%.

In formula (3), the contrast Co represents the Michelson Contrast between Ith and T. That is, when the value of T has a sufficient ratio that cannot be ignored with respect to Ith, the numerator becomes relatively small relative to the denominator, and the contrast Co also becomes small. In this case, it is expected that the fidelity improvement effect is different from the expectation, and the following concerns arise.

When the resist is a negative type, the crosslinking reaction proceeds by irradiating exposure light, and it is in a state where it is not eluted by development.

In addition to the ideal model, there are more or less half-finished photoreactions or half-way developing behaviors in real photosensitive materials. As a result, there is a risk that a crosslinking reaction will locally proceed on the transferred body 51 at a portion that does not require a structure including a resist (for example, a portion where the black matrix 52 should not be formed). Residue remains after development. That is, if the value of the transmittance T is close to Ith, there may be a possibility that the risk of crosslinking reaction at the part where the above-mentioned structure is unnecessary and residues remaining may increase. In order to avoid this situation, the transmittance T of the transmission control unit 36 is preferably in a range not exceeding 20% of the light intensity threshold value Ith of exposure. The contrast Co2 in the case where the transmittance T is 20% of the light intensity threshold value Ith of the exposure was calculated using the formula (4).

[number 3]

That is, the contrast Co is preferably set to 0.667 or more.

Also, considering the possibility of fluctuations (variations in irradiation intensity, in-plane unevenness in development, etc.) The transmittance T of 36 is more ideally less than 10% of the light intensity threshold value Ith of exposure. The contrast Co1 in the case where the transmittance T is 10% of the light intensity threshold value Ith of exposure was calculated by the following formula (5).

[number 4]

That is, the contrast Co is more preferably 0.818 or more. Moreover, it can be seen from the above formulas (4) and (5) that the value of the preferred contrast ratio Co has nothing to do with the value of Ith.

Furthermore, in order to more directly evaluate the degree of reflection (fidelity) of the transfer pattern 35 formed on the photomask 10 on the transfer target 51, the pattern formed on the transfer target 51 by proximity exposure was obtained by simulation. The transfer image of the pattern 35 for transfer on the upper surface, and the difference in shape between the obtained transfer image and the pattern 35 for transfer is quantified and calculated as a difference S.

The difference S corresponds to the area of the difference between the shape of the transfer pattern 35 on the photomask 10 and the shape of the transferred image formed on the transfer target body 51 . The differential S system is defined using (6) formula. The closer the difference S is to 0, the better the so-called fidelity of faithfully transferring the pattern for transfer on the photomask 10 to the body to be transferred 51 is.

S＝S1＋S2 ‥‥‥(6) Here, S1 is a region constituting the black matrix 52 if the transfer pattern 35 of the photomask 10 is faithfully transferred, but in the transferred image obtained by simulation, the light intensity does not satisfy the light intensity threshold value Ith of exposure , therefore refers to the area that becomes the area that does not constitute the black matrix 52 .

On the other hand, S2 is a region that does not constitute the black matrix 52 if the transfer pattern 35 of the photomask 10 is faithfully transferred, but in the transfer image obtained by simulation, the light intensity exceeds the threshold value Ith, and It refers to the area that becomes the region constituting the black matrix 52 .

That is, S1 and S2 can be considered as absolute values of errors (deviation amounts) from the negative side and the positive side of the faithful transfer, respectively, and the total of them is evaluated here. Furthermore, the numerical coefficients of S1 and S2 are quantized by calculating the number of pixels of the above-mentioned deviation part when outputting to a square of 680 pixels, and multiplying it by u of the pixel unit area.

Fig. 7 is for the transfer pattern 35 having the shape of Fig. 1 and the size of Table 1, by simulating and utilizing the distribution of the value and shape difference of the difference S (Fig. The effect on the transferred image when G is set to 100 μm and the phase shift amount of the transmission control unit 36 is changed. Specifically, as in Comparative Example 1 in which the transmittance of the binary mask was set to zero, the transmittance of the transmission control part 36 was set to 0.03 (3%), and the phase shift with respect to the transmission control part 36 was obtained. The distribution of the difference S and the shape difference corresponding to the difference S when the quantity is set to each of 0 degrees, 90 degrees, 180 degrees, and 270 degrees. Furthermore, here, the light intensity threshold value Ith of the exposure is set to be 6 μm in the portion corresponding to the narrow black matrix 52 on the transferred body 51 (the portion corresponding to the width D of the light-transmitting portion 37 in FIG. 1 ). set in the same way.

Regarding the shape (a) of the pattern 35 for transfer, the following can be known by observing the distribution of the shape difference for calculating the above-mentioned S and the numerical value of S to quantify it. Compared to (b) Comparative Example 1 (binary mask, hereinafter also referred to as "binary") or (c) Reference Example 1 (half-tone mask without phase shift, hereinafter also referred to as "no phase difference") HTM"), the value of the difference S of Embodiment 1 of (f) with a phase shift greater than 180 degrees is the lowest, and the fidelity is excellent.

The reference example 3 shown in (e) using the so-called halftone phase shift mask (hereinafter also referred to as "180-degree PSM") with a phase shift of 180 degrees and passing through the control unit 36 is compared with that shown in (b) The binary mask of Comparative Example 1 has low fidelity.

The above-mentioned tendency can also be grasped visually from the distribution of shape differences in FIG. 7 . That is, it can be seen that the photomask 10 of the first embodiment can obtain a transfer image superior to any of the previous photomasks by setting the phase shift amount of the transmission control unit 36 to a value exceeding 180 degrees.

In general, the proximity exposure method is performed by setting the proximity gap to a specific value (for example, 100 μm), but in reality it is impossible to set the distance from the transfer object 51 to this value throughout the entire in-plane area of the photomask 10 . For example, in the photomask 10 for a large-sized flat panel display, bending due to its own weight occurs during proximity exposure, and therefore, the proximity gap differs between near the center and outer edge of the photomask 10 . Alternatively, there may be a case where a more complicated in-plane distribution (nonuniformity) of the proximity gap occurs due to a holding mechanism or the like that applies a load to the photomask 10 for the purpose of reducing the curvature.

Therefore, in the above-mentioned simulation, the result of examining the fidelity of the case where the proximity gap G is 150 μm is shown in FIG. 8 . In this case, the proximity gap of 150 μm is accidentally generated due to in-plane distribution, etc. Therefore, the value of Ith derived at 100 μm, which is a specific proximity gap value set intentionally, is used as the light intensity threshold value of exposure.

According to FIG. 8 , as in FIG. 7 , compared to the binary mask shown in (b) or the 180-degree PSM shown in (e), in the mask 10 of Example 2 shown in (f), The shape variation is small and exhibits excellent fidelity.

From the above, it can be seen that when it is desired to apply a phase shift film to the photomask 10 for proximity exposure to improve the resolution by using the phase shift effect, the amount of phase shift is 180 established in the projection exposure method. degree of phase shift may not be optimal. That is, it was found that when the phase shift used in the proximity exposure method acts on the phase shift amount exceeding 180 degrees, more excellent fidelity is exhibited. In particular, it can be seen that in this case, the shape stability of the transferred image is remarkably excellent with respect to the variation of the proximity gap G. This aspect can also be understood based on the fact that the difference between Embodiment 1 and Embodiment 2 (that is, the difference in the difference S between FIG. 7( f ) and FIG. 8( f )) is small.

Next, more detailed optical simulations are presented on the fidelity of the obtained transferred images.

及透過率T分別變化時，對透過控制部36之相位偏移量

、透過率T、轉印像之對比度Co、差分S之關聯進行調查所得者。The following optical simulation is based on the transfer pattern 35 in Fig. 1, in the phase shift

When the transmittance and transmittance T are changed respectively, the phase shift amount of the transmission control unit 36

, Transmittance T, contrast Co of the transferred image, and difference S are investigated.

與透過率T之組合進行各種變更而實施。於圖9中，橫軸表示相位偏移量

(度)，縱軸表示透過率T。以虛線表示交界之一個個長方形框表示各者之模擬條件。FIG. 9 is an explanatory diagram illustrating a method of displaying simulation results. The analog system makes the phase shift through the control unit 36

Combinations with the transmittance T were variously changed and implemented. In Figure 9, the horizontal axis represents the phase offset

(degrees), the vertical axis represents the transmittance T. The individual rectangular boxes with dotted lines representing the boundaries represent the simulation conditions for each.

為360度、即0度且無相位差之HTM。粗線包圍之M部表示180度PSM。粗線包圍之N部表示相位偏移量

超過180度且未達360度之透過控制部36。於以下說明中，將具備相當於N部之透過控制部36之光罩10亦稱為過偏移角相移光罩。The portion K surrounded by a thick line represents a binary mask in which the transmittance T of the transmission control portion 36 is 0, that is, the transmission control portion 36 does not transmit light. The part L surrounded by a thick line represents the phase shift amount passed through the control unit 36

It is HTM with 360 degrees, that is, 0 degrees and no phase difference. The part M surrounded by thick lines represents 180-degree PSM. The part N surrounded by a thick line represents the phase offset

More than 180 degrees and less than 360 degrees pass through the control unit 36 . In the following description, the mask 10 provided with the transmission control section 36 corresponding to the N section is also referred to as an over-offset phase shift mask.

藉由模擬器特性而於每個波長與特定值一致。又，近接間隙G設為100 μm。In the simulation, as light for exposure, exposure conditions of a wide wavelength region including light having wavelengths of 313 nm, 334 nm, and 365 nm (intensity ratio 0.25:0.25:0.5) were applied. These are the main peak components below the i-ray in the photosensitive region of the negative-type resist used in the manufacture of the black matrix 52 and the like in the emission spectrum of the high-pressure mercury lamp. Transmittance T and phase difference

Consistent with specific values at each wavelength by simulator characteristics. Also, the proximity gap G was set to 100 μm.

Moreover, the pattern 35 for transfer of the photomask 10 is the same as what demonstrated about FIG. 7. FIG.

In addition, in this simulation, the values of the contrast Co and the difference S in each of the above-mentioned simulation conditions were calculated, and were associated with each rectangular frame shown by the dotted line in FIG. 9 .

10 to 12 are explanatory diagrams illustrating simulation results. Figure 10 shows the situation where the proximity gap G is 100 μm, and the part surrounded by thick lines shows that the difference S obtained by using the offset angle phase shift mask is compared with the HTM and 180-degree PSM with the same transmittance (0.03) without phase difference Small and smaller than binary regions.

That is, the area within the thick line is the area where the fidelity of the transfer in the cross-offset phase shift mask is superior to any of the binary, phase-difference-free HTM, and 180-degree PSM.

FIG. 11 shows the simulation results performed under the same conditions as those in FIG. 10 except that the proximity gap G was set to 150 μm. The part surrounded by a thick line represents the area where the fidelity of the cross-offset phase-shift mask is superior to any of the binary, phase-difference-free HTM, and 180-degree PSM under the same benchmark as above.

Generally, when the proximity gap G becomes larger than a set value, there exists a tendency for the deterioration of a transfer image to become remarkable. This aspect can also be grasped according to Fig. 7 and Fig. 8 . However, it can be seen that according to the over-offset angle phase shift mask of the present invention, even if the proximity gap G changes in the plane and becomes larger than the set value, compared with the existing mask, it also shows a stable fidelity High transferability.

The area surrounded by chain lines of single dots in Fig. 12 represents the sum set of the parts surrounded by thick lines in Fig. 10 and Fig. 11 . That is, it shows the region where the fidelity of the over-offset phase shift mask is higher than that of other masks 10 when the proximity gap G is either 100 μm or 150 μm. In addition, the part surrounded by a thick line shows the part surrounded by a thick line in either of FIG. 10 and FIG. 11, that is, a common set. That is, it shows the region where the fidelity of the phase shift mask over the offset angle is high when the approach gap G is either 100 μm or 150 μm.

超過180度，則過偏移角相移光罩具有較既有之光罩更有利之保真度。According to Fig. 12, it can be seen that if the phase shift amount through the control unit 36

Beyond 180 degrees, the over-offset phase shift mask has a more favorable fidelity than existing masks.

為255度以上時，該近接間隙G時之保真度較有利。Also, according to FIG. 10, it can be seen that the phase shift amount of the transmission control unit 36

When it is more than 255 degrees, the fidelity when approaching the gap G is more favorable.

之選擇範圍較廣。Furthermore, according to FIG. 10, if the transmittance T of the transmission control unit 36 is 0.06 or less, the phase shift amount of the transmission control unit 36 for obtaining good fidelity

The selection range is wider.

為330度以下之較寬之過偏移角範圍內獲得良好之保真度。Furthermore, according to FIG. 11 , when the proximity gap is enlarged unexpectedly due to in-plane distribution, etc., the phase shift amount passing through the control unit 36

Good fidelity is obtained in a wide range of over-offset angles below 330 degrees.

為255度以上且330度以下時，有因近接間隙G之變動導致之對保真度之影響較小之優點，於相位偏移量

為270度以上時，該優點更顯著。Also, according to Fig. 10 to Fig. 12, the phase shift amount through the control unit 36

When it is more than 255 degrees and less than 330 degrees, there is an advantage that the influence on the fidelity caused by the change of the proximity gap G is small, and the phase offset

This advantage becomes more remarkable when it is 270 degrees or more.

之選擇範圍均較廣。Also, if the transmittance T is set to be 0.06 or less, the amount of phase shift for obtaining favorable fidelity regardless of the variation of the proximity gap G

The range of choices is wide.

設為270度以上，則用以獲得有利之保真度之透過率T之選擇範圍較廣。Furthermore, if the phase offset of the over-offset angle phase shift mask

If it is set at 270 degrees or more, the selection range of the transmittance T for obtaining favorable fidelity is wider.

13 shows the results of calculating the contrast Co of the transferred image formed on the transfer target body 51 . The W part surrounded by a thick line is a region where the contrast Co becomes 0.667 or more (but less than 0.818), and the V part surrounded by a thick line is a region where the contrast Co becomes 0.818 or more. That is, the area W is a preferable range obtained by using the above formula (4), and the area V is a more preferable range obtained by using the above formula (5).

或透過率T之條件以外，進而一併考慮圖13中之有利之對比度Co之範圍，可獲得更佳之轉印性。Therefore, it can be seen that by dividing the above-mentioned better phase offset with favorable fidelity

Or in addition to the condition of transmittance T, and further considering the favorable range of contrast Co in FIG. 13 , better transferability can be obtained.

為225度以上時，用以獲得對比度良好之轉印像之適用透過率T之範圍擴大，若將相位偏移量

設為270以上，則可獲得進而擴大之有利之效果。For example, it can be known that the phase shift amount transmitted through the control unit 36 in the over-shift angle phase shift mask

When it is more than 225 degrees, the range of applicable transmittance T used to obtain a transfer image with good contrast is expanded. If the phase shift

If it is set to be 270 or more, a beneficial effect of further expansion can be obtained.

之較寬之範圍內獲得對比度良好之轉印像。 若透過率T為： 0.01≦T≦0.08， 則其優點更顯著。Also, the value of the transmittance T is preferably 0.1 or less as mentioned above, especially, if it is: 0.01≦T≦0.09, then the phase shift amount of the transmission control unit 36

A transfer image with good contrast can be obtained in a wide range. If the transmittance T is: 0.01≦T≦0.08, the advantages are more significant.

之選擇範圍較高。Furthermore, if the transmittance T is: T≦0.05, then a better contrast Co can be obtained; if it is: T≦0.04, the phase shift of the transmission control part 36 used to obtain a better contrast

The range of choices is high.

[Embodiment 2] FIG. 14 shows a case where the design shape of the transfer pattern 35 which the photomask 10 has is changed from the first embodiment. That is, the pattern 35 for transfer which this photomask 10 has has the repeating pattern of a parallelogram instead of a rectangle. For example, consider a design in which the shape of the sub-pixels of a flat panel display is a parallelogram.

In FIG. 14 , the transmission control part 36 is a parallelogram whose base length is C, height is B, the angle of the acute part is 45 degrees, and the angle of the obtuse part is 135 degrees. The transmission control parts 36 are arranged in a matrix at intervals of D in the height direction and intervals of E in the direction along the bottom. The pattern 35 for transfer of the present embodiment 2 is set to be the same as that of the first embodiment except for the design changes of these patterns, and the dimensions of A to E here are set to those shown in Table 1. Same size.

FIG. 15 shows the shape of the black matrix 52 formed on the transfer target 51 assuming that the transfer pattern 35 shown in FIG. 14 is faithfully transferred to the transfer target 51 . It is set as the black matrix 52 in an ideal state. However, in practice, when the transfer pattern 35 in FIG. 14 is subjected to proximity exposure, shape degradation due to diffraction and interference of light occurs in the transferred image on the transfer target body 51 .

Here, for the case of performing proximity exposure on the transfer pattern 35 shown in FIG. 14 , the results of the same optical simulation as those performed in the aforementioned FIGS. 7 and 8 are shown in FIGS. 16 and 17 .

That is, for the transfer pattern 35 in FIG. 14, the transferred image and the difference d are shown when the phase shift amount of the transmission control part 36 is changed with the distance D set at 6 μm and the proximity gap G set at 100 μm. In Figure 16(b)~(e). Specifically, as in Comparative Example 4 in which the transmittance of the binary mask was set to zero, the transmittance of the transmission control part 36 was set to 0.03 (3%), and the phase shift amount of the transmission control part 36 was set to Calculate the difference d for various situations of 0°, 90°, 180°, and 270°. In addition, here, Ith normalizes the light intensity so that the narrow black matrix 52 (corresponding to the D part of the transfer pattern 35) becomes 6 micrometers. The collimation angle of the close-up exposure was set to 2.0 degrees. The simulation conditions were set to be the same as those in the first embodiment.

Furthermore, FIG. 17 shows the results of simulations performed under the same conditions as those in FIG. 16 except that the proximity gap G was 150 μm.

According to Figure 16 and Figure 17, compared with the binary mask or 180-degree PSM, according to the value of the difference d, the transfer fidelity of the over-offset phase-shift mask of Example 3 and Example 4 is excellent . Also, according to Figure 16, when the proximity gap G is 100 μm, the fidelity of the HTM without phase difference is slightly better than that of Example 3, but according to Figure 17, if the proximity gap G is changed to 150 μm, the embodiment The numerical value of the difference d of 4 becomes the more excellent one. Furthermore, in the proximity exposure, when the proximity gap G is formed differently depending on the position in the plane, it can be understood from Examples 3 and 4 that the change amount of the difference d is small according to the variation of the proximity gap G. This aspect is very significant in maintaining the in-plane uniformity of the transferred pattern, especially in the manufacture of flat panel displays.

FIG. 18 to FIG. 20 are explanatory diagrams illustrating the results of the same simulation as in FIG. 9 to FIG. 11 described above.

Figure 18 shows the situation where the proximity gap G is 100 μm, and the part surrounded by thick lines shows that the fidelity of the over-offset phase-shift mask is better than that of the binary, no-phase-difference HTM, and 180-degree PSM area. That is, the area within the thick line is the area where the above-mentioned difference d in the cross-offset phase shift mask is smaller than that of the binary, and thus smaller than either of the HTM with no phase difference and the 180-degree PSM with the same transmittance .

FIG. 19 shows the simulation results performed under the same conditions as those in FIG. 18 except that the proximity gap G was set to 150 μm. The part enclosed by the thick line indicates the area where the fidelity of the over-offset phase-shift mask is superior to any of the binary, phase-difference-free HTM, and 180-degree PSM.

The area surrounded by chain lines of single dots in Fig. 20 represents the sum set of the parts surrounded by thick lines in Fig. 18 and Fig. 19 . That is, it shows the region where the fidelity of the over-offset phase shift mask is high when the gap G is either 100 μm or 150 μm. In addition, the part surrounded by a thick line shows the part surrounded by a thick line in either of FIG. 18 and FIG. 19, that is, a common set. That is, it shows the region where the fidelity of the phase shift mask over the offset angle is high when the approach gap G is either 100 μm or 150 μm.

超過180度時，過偏移角相移光罩具有較既有之光罩更有利之保真度。又，可知，於相位偏移量

為300度以上時，可獲得尤其良好之結果。It can be seen from Fig. 20 that the phase offset through the control unit 36

Over 180 degrees, the over-offset phase shift mask has a more favorable fidelity than existing masks. Also, it can be known that the phase offset

Especially good results can be obtained when it is 300 degrees or more.

Also, similarly to the first embodiment, by taking into account the range in which the contrast Co obtained by using FIG. 13 is good, conditions that are more favorable for fidelity can be selected.

As shown in Embodiments 1 and 2 above, according to the over-offset phase shift mask, it is possible to provide a photomask 10 that can perform photolithography with good fidelity using the proximity exposure device 50 .

Moreover, according to the above embodiment, even when the proximity gap G varies due to the in-plane position of the mask 10, the change in the shape (including CD) of the transferred image can be reduced. In particular, in a large-sized photomask 10 used for a flat panel display, bending due to its own weight or variation of the proximity gap G due to the holding means of the exposure device is likely to occur, so it is more effective to use the photomask 10 of this embodiment. .

Furthermore, according to the said embodiment, the photomask 10 which can perform high-fidelity exposure by combining the resist using a negative photosensitive material and a high-pressure mercury lamp can be provided.

The transmission control film constituting the transmission control part 36 is one whose composition or film thickness is determined in order to have a specific exposure light transmittance and phase shift, and its composition may be uniform in the film thickness direction, or may be A permeation control film is formed by laminating films of different compositions or different physical properties.

However, within the scope of not impairing the effect of the present invention, different films (shading film, etch stop film, etc.) The film pattern obtained by the additive film.

Also, an additional film pattern (for example, a light-shielding film pattern) may be provided on the outer peripheral side of the pattern 35 for transfer, and such an additional film pattern may be referred to when forming the photomask 10 during exposure or operation. Mark pattern.

In common with the above-mentioned two embodiments, the photomask 10 of this invention can be manufactured by the following manufacturing methods, for example.

First, a photomask base in which a transmission control film is formed on a transparent substrate 21 is prepared. When the transmission control film is formed, its material and film thickness are selected so as to satisfy a specific transmittance and phase shift amount with respect to the exposed light. As a film-forming method, a known film-forming method such as a sputtering method can be applied.

Next, a resist-attached photomask base in which a resist film was formed on the transmission control film was prepared. The resist may be positive or negative, but is preferably positive.

Then, patterning is carried out on the above-mentioned photomask substrate with resist. Specifically, drawing using specific pattern data is performed using a drawing device such as a laser drawing device, and development is performed. Furthermore, dry or wet etching is performed on the transmission control film by using the resist pattern formed by development as a photomask, and the transfer pattern 35 is formed. Then, the resist pattern is peeled off.

According to the above steps, the photomask 10 can be formed by only one patterning (that is, only one drawing). That is, it is preferable that it is the photomask 10 which patterned only the transmission control film. Additional film formation and patterning may also be performed as needed.

The material of the transmission control film can be, for example, a film containing Si, Cr, Ta, Zr, etc., or a suitable one can be selected from their compounds.

As a film containing Si, Si compounds (SiON, etc.), or transition metal silicides (MoSi, TaSi, ZrSi, etc.) or their compounds (oxides, nitrides, carbides, oxynitrides, oxycarbonitrides, etc.) Wait).

As the Cr-containing film, Cr compounds (oxides, nitrides, carbides, oxynitrides, carbonitrides, oxycarbonitrides) can be used.

The present invention includes a method of manufacturing an electronic component for a flat panel display using the photomask 10 .

That is, it is a method of manufacturing electronic components for flat panel displays, which includes the following steps: preparing the above-mentioned over-offset angle phase shift mask; The photomask is exposed, and the transfer pattern 35 is transferred onto the transfer target body 51; and in the transfer step, a proximity exposure with a proximity gap of 50-200 μm is used.

The use of the photomask 10 can be preferably used in the manufacture of black matrix 52 or black stripes, but is not limited thereto. Among them, the photomask of the present invention is particularly preferably used for the purpose of forming a three-dimensional structure using a photosensitive material on a transfer target. The reason is that it is very meaningful to obtain excellent fidelity in the shape of the three-dimensional structure formed by the transmission control part surrounded by the above-mentioned closed line and the light transmission part surrounding it.

Also, the present invention can be suitably applied to a pattern for transfer of a so-called dense pattern including a unit pattern regularly repeating at a distance optically influencing each other like a line-and-space pattern.

The technical features (components) described in each embodiment can be combined with each other, and new technical features can be formed through the combination. Embodiments 1 and 2 disclosed this time should be considered as illustrative and not restrictive in any respect. The scope of the present invention is not the above-mentioned meaning, but is indicated by the scope of the patent application, and all changes within the meaning and range equal to the scope of the patent application are intended to be included.

10: Mask 11: front 12: back 21: Transparent substrate 35:Pattern for transfer printing 36: Through the control department 37: Translucent part 50: Proximity exposure device 51: Transferred body 52: Black matrix 56: Transferred body (glass substrate) 57: light source 58:Lighting system

FIG. 1 is a diagram showing an example of a transfer pattern for forming a black matrix. FIG. 2 is a cross-sectional explanatory view showing a state in which a black matrix is formed on a glass substrate constituting a transfer target. FIG. 3 is an explanatory diagram schematically showing the configuration of a proximity exposure device. FIG. 4 is a diagram showing an example of the shape of a black matrix formed on a to-be-transferred body on the assumption that the transfer pattern shown in FIG. 1 is faithfully transferred to the to-be-transferred body. Fig. 5 shows that when the binary photomask having the transfer pattern shown in Fig. 1 is subjected to proximity exposure and transferred onto the transfer object, the shape is deteriorated due to light diffraction and interference. A picture of the transfer image of the situation. Fig.6 (a), (b) is explanatory drawing explaining the transfer image formed by the photomask 10 and proximity exposure. Figures 7(a) to (f) use the value of the difference S and the distribution of the shape difference to show that for the transfer pattern with the shape of Figure 1 and the size of Table 1, the proximity gap G is set to 100 μm and the transmission control part The diagram of the effect on the transfer image when the phase shift of . 8( a ) to ( f ) show the results of studying the fidelity of the case where the proximity gap G is 150 μm in the simulation. FIG. 9 is an explanatory diagram illustrating a method of displaying simulation results. Fig. 10 is an explanatory diagram illustrating simulation results. Fig. 11 is an explanatory diagram illustrating simulation results. Fig. 12 is an explanatory diagram illustrating simulation results. Fig. 13 shows the results of calculation of the contrast Co of the transferred image formed on the transferred body. FIG. 14 shows another example of the transfer pattern for black matrix formation. FIG. 15 shows the shape of the black matrix formed on the transfer target under the assumption that the transfer pattern shown in FIG. 14 is faithfully transferred to the transfer target. FIGS. 16( a ) to ( f ) show the results of optical simulations similar to those performed in FIGS. 7 and 8 in the case of performing proximity exposure on the pattern for transfer shown in FIG. 14 . FIGS. 17( a ) to ( f ) are diagrams showing results of optical simulations similar to those performed in FIGS. 7 and 8 in the case of performing proximity exposure on the pattern for transfer shown in FIG. 14 . Fig. 18 is an explanatory diagram illustrating the results of the same simulation as Figs. 9 to 11 . FIG. 19 is an explanatory diagram illustrating the results of the same simulation as in FIGS. 9 to 11 . FIG. 20 is an explanatory diagram illustrating the results of the same simulation as in FIGS. 9 to 11 . FIG. 21 is a schematic diagram showing how the exposure light transmitted through the mask reaches any point on the transfer target in proximity exposure.

Claims (28)

A photomask for proximity exposure comprising a transfer pattern formed by patterning only one transmission control film formed on a transparent substrate, the transfer pattern having only the transmission control film formed on the transparent substrate The formed transmission control part and the light transmission part for exposing the above-mentioned transparent substrate, the above-mentioned transmission control part has a phase shift of more than 180 degrees relative to light with a wavelength of 313nm, 334nm, 365nm, 405nm or 436nm. When the photosensitive material on the to-be-transferred body on which the above-mentioned transfer pattern is printed is a negative type, the above-mentioned transmission control part corresponds to the region where the above-mentioned photosensitive material is eluted by exposure and development using the above-mentioned photomask. When the transmittance of the above-mentioned transmission control part is T, and the threshold value of light intensity at which the resist film on the above-mentioned transfer target becomes insoluble by development is Ith, it is defined as (Ith-T)/(Ith+T) The contrast ratio is above 0.667. Such as the photomask of Claim 1, which is used for exposure of negative photosensitive materials. The photomask according to claim 1 or 2, wherein the transmittance of the above-mentioned transmission control part with respect to the exposed light is 10% or less. The photomask according to claim 1 or 2, wherein the pattern for transfer has a linear light-transmitting portion with a width of 3-10 μm. The photomask according to claim 1 or 2, wherein the pattern for transfer is a linear pattern with a width of 10 μm or less formed on the negative photosensitive material on the transfer object. The photomask according to claim 1 or 2, wherein the pattern for transfer has a repeating pattern in which the transmission control part and the light-transmitting part are regularly arranged, and the repeating pitch of the repeating pattern is 10-35 μm. The photomask according to claim 1 or 2, wherein the transfer pattern has a repeating pattern in which the transmission control part and the light transmission part are regularly arranged, and the transmission control part has a shape surrounded by closed lines. The photomask according to claim 1 or 2, wherein the transfer pattern has a repeating pattern in which the transmission control parts are regularly arranged, and the transmission control parts are quadrangular. The photomask according to claim 1 or 2, wherein the transmission control part has a phase shift of 255 degrees or more relative to the exposure light. The photomask according to claim 1 or 2, wherein the transmission control part has a phase shift of 300 degrees or more relative to the exposure light. The photomask according to claim 1 or 2, wherein the transmission control part has a phase shift of 330 degrees or less with respect to the exposure light. The photomask according to claim 1 or 2, wherein the pattern for transfer is a pattern for forming a black matrix or black stripes. The photomask according to claim 1 or 2, wherein the transmission control parts are arranged in a matrix with the light transmission parts interposed therebetween. A method of manufacturing electronic components for flat panel displays, comprising the following steps: preparing a photomask according to any one of claims 1 to 13; and a transfer step, which is to expose the above photomask by a proximity exposure device, and The above transfer pattern is transferred to the negative photosensitive material film formed on the object to be transferred; and in the above transfer step, the proximity exposure with the proximity gap set in the range of 50 to 200 μm is applied. A method for manufacturing a photomask for proximity exposure, the photomask for proximity exposure is equipped with a transfer pattern formed by patterning only one transmission control film formed on a transparent substrate, the method includes the following steps: preparing the transparent substrate on the above-mentioned transparent substrate A photomask base on which the above-mentioned transmission control film is formed; and a patterning step, which is to pattern the above-mentioned transmission control film to form the above-mentioned transfer pattern; the above-mentioned transfer pattern only has the above-mentioned The transmission control part formed by passing through the control film, and the light-transmitting part exposed from the above-mentioned transparent substrate, the above-mentioned transmission control part has a transmittance of 10% or less and a transmittance of more than 180 degrees relative to light with a wavelength of 313nm, 334nm, 365nm, 405nm or 436nm The phase offset of When the photosensitive material on the transfer object to which the transfer pattern is transferred is a negative type, the transmission control unit corresponds to the process of eluting the photosensitive material by exposure and development using the photomask. area, and when the transmittance of the above-mentioned transmission control part is T, and the threshold value of the light intensity at which the resist film on the above-mentioned transferred body becomes insoluble by development is Ith, it is defined as (Ith-T)/( The contrast ratio of Ith+T) is above 0.667. The method of manufacturing a photomask as claimed in item 15 is for exposure of negative-type photosensitive materials. The method of manufacturing a photomask according to claim 15 or 16, wherein the transmittance of the above-mentioned transmission control part with respect to the light to be exposed is 10% or less. The method of manufacturing a photomask according to claim 15 or 16, wherein the pattern for transfer has a linear light-transmitting portion with a width of 3-10 μm. The method of manufacturing a photomask according to claim 15 or 16, wherein the above-mentioned transfer pattern is formed into a linear pattern with a width of 10 μm or less on the negative photosensitive material on the transfer target. The method of manufacturing a photomask according to claim 15 or 16, wherein the pattern for transfer has a repeating pattern in which the transmission control part and the light-transmitting part are regularly arranged, and the repeating pitch of the repeating pattern is 10-35 μm. The method of manufacturing a photomask according to claim 15 or 16, wherein the above-mentioned pattern for transfer has the above-mentioned A repeating pattern in which the transmission control part and the above-mentioned light-transmitting part are regularly arranged, and the above-mentioned transmission control part has a shape surrounded by closed lines. The method of manufacturing a photomask according to claim 15 or 16, wherein the transfer pattern has a repeating pattern in which the transmission control parts are regularly arranged, and the transmission control parts are quadrangular. The method of manufacturing a photomask according to claim 15 or 16, wherein the transmission control part has a phase shift of 255 degrees or more relative to the exposure light. The method of manufacturing a photomask according to claim 15 or 16, wherein the transmission control part has a phase shift of 300 degrees or more relative to the exposure light. The method of manufacturing a photomask according to claim 15 or 16, wherein the above-mentioned transmission control part has a phase shift amount of 330 degrees or less with respect to the exposure light. The method for manufacturing a photomask according to claim 15 or 16, wherein the pattern for transfer is a pattern for forming a black matrix or black stripes. The method of manufacturing a photomask according to claim 15 or 16, wherein the transmission control parts are arranged in a matrix with the light transmission parts interposed therebetween. A method of manufacturing electronic components for flat panel displays, which includes the following steps: preparing a photomask obtained by using the manufacturing method according to any one of claims 15 to 27; The transfer step is to expose the above-mentioned photomask by a proximity exposure device, and transfer the above-mentioned transfer pattern to the negative photosensitive material film formed on the transfer object; and in the above-mentioned transfer step, apply Proximity exposure with a proximity gap set to a range of 50 to 200 μm.

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