JP2020067661A - Photomask, manufacturing method of electronic device and manufacturing method of photomask - Google Patents

Abstract

To provide a photomask capable of performing a pattern transfer with high fidelity using a proximity exposure apparatus.SOLUTION: A photomask 10 is a photomask for proximity exposure, including a transfer pattern formed by patterning a permeability control film formed on a transparent substrate 21. The transfer pattern includes: a permeability control part 36 obtained by forming a permeability control film on the transparent substrate; and a translucent part 37 at which the transparent substrate is exposed. The permeability control part 36 has a phase shift amount over 180 degrees with regard to exposure light that exposes the photomask.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a photomask, a method for manufacturing an electronic device, and a method for manufacturing a photomask.

  In manufacturing electronic devices 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 photomask for manufacturing a semiconductor integrated circuit (hereinafter, referred to as LSI: Large-scale Integrated Circuit). In this photomask, the light-shielding region of the binary mask has a transmittance that does not transfer a pattern, and the structure of shifting the phase of transmitted light by 180 degrees improves the resolution performance (Non-patent Reference). Reference 1).

  On the other hand, also in the image display device, the number of pixels is increased, and there is a demand for a device having a higher resolution. Therefore, it is attempted to use the phase shift mask used in the manufacture of the LSI for the manufacture of the image display device. (Patent Document 1).

  Further, a multi-tone halftone mask used for manufacturing a flat panel display is known. For example, a semi-transmissive film pattern and a light shielding film pattern having a transmittance of 20 to 50% and a phase difference of 60 to 90 degrees are provided on a transparent substrate. By using such a multi-tone halftone mask, a photoresist pattern having a different film thickness depending on the position can be formed by one exposure, and the number of lithography steps in the manufacturing process of the flat panel display can be reduced. Therefore, the manufacturing cost can be reduced. A halftone mask for such an application can realize three gradations with a transparent substrate, a semi-transmissive film, and a light-shielding film, and a half-tone mask with four or more gradations using a semi-transmissive film with a plurality of transmittances. It is also possible to realize a tone mask. (Patent Document 2).

JP, 2014-092727, A JP, 2018-005072, A

Isao Tanabe, Youichi Takebana, Morihisa Homoto, "Basic Technology for Manufacturing Photomask Electronic Components", First Edition, Tokyo Denki University Press, April 20, 2011, p. 245-246

  A proximity exposure method may be applied in the manufacturing process of the flat panel display. The proximity exposure apparatus is inferior in resolution performance to the projection exposure apparatus, but the apparatus configuration is not provided between the photomask and the transfer target (display substrate, etc.). It is simple, the device is relatively easy to introduce, and the manufacturing cost is high. For this reason, the proximity exposure apparatus is mainly applied to manufacture a black matrix or a black stripe used for a color filter (CF: Color Filter) of a liquid crystal display device, or a photo spacer (PS: Photo Spacer). It can also be used as a black matrix of an organic EL display device.

  On the other hand, due to the demand for increased pixel density, increased brightness, and power saving of flat panel displays, there is a marked tendency toward finer transfer patterns in photomasks used in the manufacturing process. If a projection exposure method is used for transferring a fine pattern, the resolution is advantageous, but the above advantages of proximity exposure are lost.Therefore, it is new to apply a close exposure method and precisely transfer a fine pattern. It is a problem.

The first aspect of the present invention is
A photomask for proximity exposure, comprising a transfer pattern formed by patterning a transmission control film formed on a transparent substrate, wherein the transfer pattern has a transmission control film formed on the transparent substrate. And a translucent part exposing the transparent substrate, wherein the transmissive control part is a photomask having a phase shift amount of more than 180 degrees with respect to exposure light for exposing the photomask. is there.

The second aspect of the present invention is
A photomask for proximity exposure, comprising a transfer pattern formed by patterning a transmission control film formed on a transparent substrate, for performing proximity exposure with exposure light having a wavelength in the wavelength range of 313 to 365 nm. In the photomask of, the transfer pattern has a transmission control part formed by forming a transmission control film on the transparent substrate, and a translucent part where the transparent substrate is exposed, and the transmission control part has a wavelength of A photomask having a phase shift amount of more than 180 degrees with respect to 365 nm light.

A third aspect of the present invention is
The photomask according to the first or second aspect, which is for exposing a negative photosensitive material.

A fourth aspect of the present invention is
The transmission controller is the photomask according to any one of the first to third aspects, which has a transmittance of exposure light of 10% or less.

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

A sixth aspect of the present invention is
The transfer pattern is a photomask according to any one of the first to fourth aspects, which forms a line-shaped pattern having a width of 10 μm or less on the negative photosensitive material on the transfer target. .

A seventh aspect of the present invention is
The transfer pattern has a repeating pattern in which the transmission control unit and the light transmitting unit are regularly arranged, and the repeating pitch of the repeating pattern is 10 to 35 μm. Are three photomasks.

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

A ninth aspect of the present invention is
The transfer pattern is a photomask according to any one of the first to seventh aspects, in which the transmission control unit has a repeating pattern in which the transmission control units are regularly arranged, and the transmission control unit is a quadrangle. .

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

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

A twelfth aspect of the present invention is
The transmission controller is the photomask according to any one of the first to eleventh aspects, which has a phase shift amount of 330 degrees or less with respect to the exposure light.

A thirteenth aspect of the present invention is
The transfer pattern is the photomask according to any one of the first to twelfth aspects, which is a pattern for forming a black matrix or a black stripe.

A fourteenth aspect of the present invention is
The transfer pattern is the photomask according to any one of the first to thirteenth aspects, in which only the transmission control film is patterned on the transparent substrate.

A fifteenth aspect of the present invention is
A method for producing a photomask for proximity exposure, comprising a transfer pattern formed by patterning a transmission control film formed on a transparent substrate, comprising:
A step of preparing a photomask blank on which the transmission control film is formed on the transparent substrate;
A patterning step of patterning the transmission control film to form the transfer pattern;
Have
The transfer pattern has a transmission control section in which the transmission control film is formed on the transparent substrate, and a translucent section exposing the transparent substrate,
The transmission controller has a transmittance of 10% or less and a phase shift amount of more than 180 degrees with respect to the exposure light for exposing the photomask.
It is a method of manufacturing a photomask.

A sixteenth aspect of the present invention is
A step of preparing the photomask according to any one of the first to fourteenth aspects;
A transfer step of exposing the photomask by a proximity exposure device and transferring the transfer pattern to a negative photosensitive material film formed on a transfer target;
Have
The transfer step is a method of manufacturing an electronic device for a flat panel display, in which proximity exposure with a proximity gap set in a range of 50 to 200 μm is applied.

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

An example of a transfer pattern for forming a black matrix is shown. FIG. 6 is a cross-sectional explanatory diagram showing a state where a black matrix is formed on a glass substrate that constitutes a transfer-receiving body. It is explanatory drawing which illustrates the structure of a proximity exposure apparatus typically. An example of the shape of the black matrix formed on the transfer target, assuming that the transfer pattern shown in FIG. 1 is faithfully transferred onto the transfer target, is illustrated. 2 shows a transferred image in the case where a binary mask having the transfer pattern shown in FIG. 1 is proximity-exposed and transferred onto a transfer target, and the shape is deteriorated by the action of light diffraction and interference. FIG. 3 is an explanatory diagram illustrating a photomask 10 and a transfer image formed by proximity exposure. With respect to the transfer pattern having the shape shown in FIG. 1 and the dimensions shown in Table 1, the effect on the transferred image when the proximity gap G is 100 μm and the phase shift amount of the transmission control unit is changed is shown in FIG. This is shown by the distribution of differences. In the simulation, the results of examining the fidelity when the proximity gap G is 150 μm are shown. It is explanatory drawing explaining the display method of a simulation result. It is explanatory drawing explaining a simulation result. It is explanatory drawing explaining a simulation result. It is explanatory drawing explaining a simulation result. The result of calculating the contrast Co of the transfer image formed on the transfer target is shown. Another example of a transfer pattern for forming a black matrix is shown. FIG. 14 shows the shape of a black matrix formed on a transfer target, assuming that the transfer pattern shown in FIG. 14 is faithfully transferred onto the transfer target. The results of optical simulations similar to those performed in FIGS. 7 and 8 are shown for the case where the transfer pattern shown in FIG. 14 is subjected to proximity exposure. The results of optical simulations similar to those performed in FIGS. 7 and 8 are shown for the case where the transfer pattern shown in FIG. 14 is subjected to proximity exposure. It is explanatory drawing explaining the result by the same simulation as in FIG. 9 to FIG. It is explanatory drawing explaining the result by the same simulation as in FIG. 9 to FIG. It is explanatory drawing explaining the result by the same simulation as in FIG. 9 to FIG. It is a schematic diagram which shows a mode that the exposure light which permeate | transmitted the photomask in proximity exposure arrives at one arbitrary point on a to-be-transferred body.

  When the design of an electronic device to be obtained, such as a flat panel display, becomes highly precise and the density increases, inconvenience will occur if the transfer pattern of the photomask used for manufacturing the device is simply miniaturized. . For example, when a transfer pattern of a black matrix having a fine pattern width (CD: Critical Dimension) is exposed using a proximity exposure method, corners of quadrilateral pixels are rounded and the pattern shape of the transferred image Degradation is likely to occur.

  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 section 36 and a light transmission section 37. The transparent portion 37 is a line-shaped portion in which the surface of the transparent substrate 21 is exposed, and the transmission control portion 36 has a quadrangular shape in which a transmission control film is formed on the transparent substrate 21. Are arranged in a matrix. That is, the transmission control unit 36 having a shape surrounded by closed lines (here, a quadrangle having four corners) is regularly spaced by a predetermined pitch in the X direction and the Y direction perpendicular to the transmission control unit 37. Are arranged in. The corner portion may have a right angle as shown in FIG. 1 or may include an acute angle or an obtuse angle as shown in Examples described later.

  By the way, in the conventional photomask, the area corresponding to the transmission control section 36 is formed as a light-shielding section in which a light-shielding film is formed on the transparent substrate 21, and the exposure light is substantially transmitted when the photomask is exposed. It was an area not to do. In this case, as the pattern becomes finer and the CD becomes smaller, the shape of the transfer image obtained by transfer onto the transfer target 51 (see FIG. 3) due to proximity exposure deteriorates, and the shape of the transfer pattern 35 becomes faithful. There was a tendency that it was not reflected.

  In FIG. 5, a conventional photomask including a light-transmitting portion and a light-shielding portion is provided on the surface of a transfer target body 51 by a proximity exposure device 50 (see FIG. 3). The shape of the black matrix 52 obtained when the material is transferred to a resist (for convenience) will be illustrated. This is an example of the case where faithful pattern transfer is not performed when the transfer pattern 35 shown in FIG. 1 is exposed. Compared to FIG. 1, the corners of the quadrangle are rounded, and the shape of the line-shaped portion is also changed.

  This is because light is diffracted at the edge of the transfer pattern 35 at the time of proximity exposure, and a gap (that is, a proximity gap) between the photomask and the transfer target 51 causes a complicated pattern on the transfer target 51. It is considered that this is because of light interference. That is, there is a problem that the light intensity distribution of the transmitted light formed on the transferred body 51 does not faithfully reflect the transfer pattern 35 of the photomask. This tendency is particularly noticeable in high-definition patterns.

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

  It is generally known that Fresnel diffraction acts on the principle of forming a transfer image by proximity exposure. FIG. 21 is a schematic diagram showing how the exposure light transmitted through the photomask 10 in proximity exposure reaches an arbitrary point on the transfer target 51. In FIG. 21, light waves are represented by a solid structure and a broken structure. The solid line indicates the crest of the wave, and the broken line indicates the trough of the wave (the peak and the valley may be reversed). It can be seen that the light transmitted through the slit SL (Slit) travels while being diffracted (wraparound) at the edge and reaches the arrival point on the transfer target 51 in various phases.

  The amplitude information U (x, y) of light at any one of the arrival points (x, y) is approximated by the following Fresnel diffraction equation (1) (JW Goodman, Introduction to Fourier Optics (3rd Edition), Roberts & Company Publishers (2016), p. 66-67).

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

  Then, a combination of the amplitude information U (x, y) at all positions within the predetermined surface on the transfer target 51 determines the light intensity distribution of the transfer image and is transferred onto the transfer target 51. .

  On the other hand, when the transfer pattern 35 of the photomask 10 is subjected to proximity exposure, in order to improve the resolution and fidelity of the transfer image formed, the phase and amplitude of the light on the transfer target 51 are optimized. Are considered useful. Therefore, it is possible that a more advantageous light intensity distribution can be generated with respect to the Fresnel diffraction generated in the existing binary mask.

  According to the study by the present inventor, when considering the above, it was found that the phase shift amount (180 degrees) of the halftone type phase shift mask used in the projection exposure is not necessarily optimum in the proximity exposure. It was

  Then, as a result of the examination, the transfer pattern 35 for proximity exposure (for example, the transmission control section 36 in FIG. 1) is formed by a transmission control film having a phase shift action, and the phase shift amount is set to the existing halftone. It has been revealed that when the size is larger than the mold phase shift mask, it is possible to reduce the shape deterioration of the transferred image obtained on the transferred body 51 and improve the fidelity of transfer.

[Embodiment 1]
The photomask 10 of the present embodiment is configured such that a predetermined transfer pattern 35 is provided on one main surface of a transparent substrate 21 having a rectangular or square main surface. As the transparent substrate 21, a transparent material such as synthetic quartz that is processed and has a main surface that is polished flat and smooth is used. As the transparent substrate 21 used for the photomask for the flat panel display, one having a short side of the main surface of 300 to 2000 mm and a thickness of 5 to 16 mm is preferably used.

  The transfer pattern 35 of the photomask 10 is illustrated in FIG. The transfer pattern 35 includes a transmission control part 36 in which a transmission control film is formed on the transparent substrate 21, and a translucent part 37 with the transparent substrate 21 exposed.

  Here, the transmission control unit 36 is a rectangle having a short side dimension of B and a long side dimension of C, and is arranged in a matrix with an interval of D in the short side direction and E in the long side direction. There is. That is, the respective transmission control units 36 are regularly arranged via the light transmitting unit 37, and the pitch Pm1 (also referred to as the longitudinal pitch) in the long side direction is Pm1 (= C + E) and the pitch Pm2 in the short side direction (Pm2 ( It is a repeating pattern of Pm2 (= B + D) in the short pitch). In the present embodiment, the transfer pattern 35 is a pattern for the black matrix 52 (see FIG. 4) used in a flat panel display, and the translucent portions 37 extending vertically and horizontally in FIG. The resulting black matrix 52 is transferred to the photosensitive material. FIG. 2 shows a cross-sectional explanatory view of a state in which the black matrix 52 is formed on the glass substrate 56 forming the transfer target 51.

  That is, the photomask 10 is a two-gradation photomask that forms a portion where the photosensitive material remains and a portion where the photosensitive material does not remain, and the transmission controller 36 corresponds to the light shielding portion of the conventional binary mask. To do.

The dimension (CD) of each portion of the transfer pattern 35 is preferably set as follows, for example. In FIG. 1, the width D of the linear translucent portion 37 (also referred to as a longitudinal slit) in the vertical direction is
3 ≦ D ≦ 10 (μm)
Is preferred, and more preferably,
3 ≦ D ≦ 8 (μm)
More preferably 3 ≦ D ≦ 6 (μm)
Is. With the above, a good black matrix 52 having a high aperture ratio can be obtained in a flat panel display. When the present invention is applied to even a high-definition pattern having such a fine CD, shape deterioration is reduced and the effect is remarkable.

In addition, the width E of the linear light-transmitting portion 37 (also referred to as a short slit) extending in the horizontal direction in FIG. 1 may be equal to or larger than the width D of the long slit.
For example, 3 ≦ E ≦ 30 (μm)
May be

In addition, the short pitch (repetition pitch) Pm2 of the repeating pattern of FIG.
10 ≦ Pm2 ≦ 35 (μm)
Can be
More preferably,
15 ≦ Pm2 ≦ 35 (μm)
Can be At this level, it can be appropriately used for a high-definition display of about 250 ppi to about 700 ppi.

On the other hand, the longitudinal pitch Pm1 is preferably larger than the above Pm2. For example,
30 ≦ Pm1 ≦ 105

  In the proximity exposure, the projection magnification is not set (that is, equal magnification), and the longitudinal pitch Pp1 and the lateral pitch Pp2 on the transfer target 51 are the same as Pm1 and Pm2.

  When proximity exposure is performed using such a transfer pattern 35, the proximity gap G is preferably about 50 to 200 μm. Further, according to the present invention, even when there is in-plane non-uniformity of the proximity gap G, the in-plane non-uniformity of the transferred image caused thereby is reduced. The collimation angle of proximity exposure is preferably about 1.5 to 2.5 degrees.

  It is considered that a line-shaped pattern having a width of 10 μm or less is formed on the transfer target 51 by using the transfer pattern 35 as described above, corresponding to the line-shaped light transmitting portion 37 having the width D. For example, it is considered that a pattern having a width of 3 to 10 μm, a finer width of 3 to 8 μm, and further a width of 3 to 6 μm is formed to form the black matrix 52 having a fine width.

In the photomask 10 of the present embodiment, the transmission control film for forming the transmission control section 36 has a function of shifting the phase of the exposure light for exposing the photomask 10 by φ (degrees). That is, the phase shift amount φ of the transmission control film is
φ> 180 (degrees)
Is.

Note that φ> 180, that is, the phase shift amount exceeding 180 degrees represents the range of the phase shift amount φ defined by the following equation (2). M in the formula (2) represents a non-negative integer.
180 + 360M <φ <360 + 360M (degree) (2)

  Here, the exposure light for exposing the photomask 10 is light used for exposing and transferring the transfer pattern 35 by the proximity exposure device 50, and light having a wavelength in the range of 313 to 365 nm is preferably used. To be In the exposure light including a plurality of wavelengths, any wavelength included in the above wavelength range (preferably a wavelength having an intensity peak) can be used as a reference wavelength for the reference of the phase shift amount φ.

  For example, when using exposure light having a wavelength in the range of 313 to 365 nm, 313 nm on the short wavelength side may be the representative wavelength, or 334 nm near the center of the wavelength range may be the representative wavelength. Further, 365 nm on the longest side of the above wavelength range can be set as the representative wavelength.

  Further, when the exposure light includes a plurality of wavelengths, φ> 180 can be set for all the wavelengths included in the above wavelength range. The same applies to the preferable wavelength ranges described below.

  Therefore, for example, the photomask 10 is a photomask 10 for performing proximity exposure with exposure light including a wavelength in the wavelength range of 313 to 365 nm, and the transmission control unit 36 has a wavelength of 365 nm on the longest wavelength side. The photomask 10 having a phase shift amount of more than 180 degrees can be obtained. In this case, the phase shift amount of the transmission controller 36 substantially exceeds 180 degrees for all the wavelengths in the above wavelength range included in the exposure light.

  Alternatively, when the wavelength of the exposure light includes 365 to 436 nm (i line, h line, g line), 436 nm on the longest wavelength side is set as the representative wavelength, and the phase shift amount φ of the transmission control film with respect to this is Φ. May be φ> 180. Furthermore, in the wavelength range of the exposure light used, the wavelength having the highest intensity may be used as the representative wavelength.

  The transmission control film for forming the transmission control section 36 has a transmittance T for exposure light. The transmittance T is a numerical value when the transparent substrate 21 is 1.0 (100%). In addition, the transmittance referred to herein can be for the same representative wavelength as that described for the phase shift amount.

The transmittance T is preferably 0.1 (10%) or less. For example, the transmittance T is
0.01 ≦ T ≦ 0.1
Can be If T is too small, the effect of improving fidelity, which will be described later, cannot be remarkably obtained with respect to the existing binary mask. If T is too large, there is a risk that the light-shielding property becomes insufficient in a region of the transmission control unit 36 that is far from the edge.

  Details of the transmittance T and the phase shift amount φ of the transmission control film will be described later.

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

  When the flat panel display is a liquid crystal display, it is manufactured by sealing liquid crystal between a color filter substrate and a TFT (Thin-Film-Transistor) substrate which are arranged opposite to each other. The black matrix 52 is formed on one surface of the color filter substrate. For example, red, green, and blue color filters can be formed in the portion corresponding to the transmission control unit 36 in FIG.

  When the flat panel display is an organic EL (electro-luminescence) 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 mixture and light leakage between the sub-pixels and makes the image / video displayed on the flat panel display clear. In order to realize a high-definition, that is, a small flat pixel display with a small individual pixel and a bright flat panel display, the width of the black matrix 52 is narrowed (for example, 3 to 10 μm, more preferably 3 to 8 μm), In addition, it is necessary to form the shape as designed.

  Therefore, it is desired to reflect the shape of the transfer pattern 35 included in the photomask 10 on the transfer image on the transfer target 51 as faithfully as possible (higher fidelity). Here, the fidelity refers to the degree to which the shape of the transfer pattern 35 of the photomask 10 is maintained on the transfer target 51. For example, the corners of the transfer pattern 35 are transferred images on the transfer target 51. It can be said that the fidelity is improved when the degree of rounding is reduced, or when the line-shaped portion of the transfer pattern 35 becomes thicker or thinner in the transferred image.

  As described above, in the transfer pattern 35, the transmission control section 36 surrounded by the closed line is arranged via the linear light transmission section 37. By the transmission control section 36, the photosensitive material on the transferred material 51 is eluted by the exposure and development using the photomask 10, and on the other hand, the portion corresponding to the translucent section 37 surrounding this is made of the photosensitive material. A three-dimensional structure (for example, a black matrix) is formed. The photomask 10 of the present invention has an excellent effect of improving the shape fidelity of this three-dimensional structure.

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

  A proximity exposure apparatus 50 is preferably used for exposing the photomask 10 of the present invention. FIG. 3 is an explanatory diagram schematically illustrating the configuration of the proximity exposure apparatus 50. The proximity exposure apparatus 50 irradiates the light emitted from the light source 57 to the back surface 12 side of the photomask 10 via the illumination system 58. The irradiated light is transmitted to the surface 11 side where the transfer pattern is formed and reaches the transfer target 51. A proximity gap G is provided between the photomask 10 and the transfer target 51.

  The light source 57 can be a high pressure mercury lamp. The high-pressure mercury lamp has strong peaks at i-line, h-line, and g-line, but the exposure of the photomask 10 of the present embodiment is performed at the i-line (wavelength λ = 365 nm) and at wavelengths shorter than that. It is preferable to utilize a spectrum group. For example, it is useful to use a negative resist having a good sensitivity range for exposure light having peaks of 365 nm, 334 nm, and 313 nm.

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

  On the other hand, FIG. 5 shows a case where the binary mask having the transfer pattern 35 shown in FIG. 1 is subjected to proximity exposure and transferred onto the transfer target 51, and the shape is deteriorated by the action of light diffraction and interference. Show the image. For example, in a conventional photomask in which the transmission controller 36 shown in FIG. 1 is used as a light shield, such shape deterioration is likely to occur. In this case, the fidelity of transfer is insufficient, such as the corners of the portions corresponding to the sub-pixels are rounded.

  Therefore, in the transfer pattern 35 shown in FIG. 1, when the transmission control film used in the transmission control unit 36 has a predetermined transmittance T and a phase shift amount φ, how the fidelity of the transferred image changes. It was verified by an optical simulation using Fresnel diffraction.

  That is, when the transfer pattern 35 is exposed by proximity exposure, the light intensity distribution of the exposure light formed on the transferred object 51 is obtained by an optical simulation to find out a better transfer condition and to transmit the transmission control film. The influence of the rate T and the phase shift amount φ on the transferred image was examined.

  The photomask 10 and a transfer image formed by proximity exposure will be described with reference to FIG. FIG. 6A shows a schematic cross-sectional view of the photomask 10 cut along the short side direction of the transmission controller 36. As described using FIG. 1, the width of the transmission control unit 36 is B and the width of the light transmitting unit 37 is D. Here, the dimension of D corresponding to the width of the black matrix 52 is a fine dimension of 10 μm or less.

  FIG. 6B shows a light intensity distribution formed on the transferred body 51 when exposed from the back surface side of the photomask 10 by the proximity exposure apparatus 50. The horizontal axis represents the position on the transfer target 51, and the vertical axis represents the light intensity.

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

  In a repetitive pattern in which light and dark are alternately repeated, such as a line and space pattern, the superiority or inferiority of a transferred image is generally evaluated by an index called contrast. The higher the contrast value, the clearer the difference in light intensity between the bright part and the dark part. Since photolithography is a method of printing transfer information on the transfer target 51 by using this difference in brightness and darkness, it is preferable to have a contrast of a certain value or more.

  Although there are several methods for quantifying the contrast, quantification by Michelson Contrast is widely used as a method focusing on the difference. Michelson Contrast is defined as {(I1-I2) / ((I1 + I2)}, where I1 is the light intensity of the bright part and I2 is the light intensity of the dark part. Ith has already been defined as an index to represent.On the other hand, it is clear from Fig. 6B that the dark part is largely controlled by the property of the transmission control unit 36. In Fig. 6B, the dark part B is shown. The case where I2 is close to 0 is illustrated assuming a sufficiently dark case. However, when the transmission control film has a significant transmittance T as will be described later, this dark portion is arranged on the photomask. Depending on the position where the image is transferred or the position where it acts on the transferred material, it may behave as light intensity that cannot be ignored.

  Based on the above, here, the contrast Co in the present embodiment is defined by the equation (3), and the influence of the transmittance T of the transmission controller 36 and the phase shift amount φ on the light intensity distribution is examined.

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

  T is a film transmittance peculiar to the transmission control film that does not consider the phase effect on the exposure light of the transmission control unit 36, and is a numerical value for which T is 1 when the transmittance is 100%.

  In the equation (3), the contrast Co indicates 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 with respect to the denominator, and the contrast Co also becomes small. At this time, in addition to the expected fidelity improvement effect, the following concerns can be expected.

  When the resist is a negative type, it undergoes a crosslinking reaction by being irradiated with exposure light and is in a state where it is not eluted by development.

  Except for the ideal model, in a real photosensitive material, there is more or less a half-finished photoreaction and a half-finished development behavior thereby. As a result, the cross-linking reaction partially progresses on the transfer target body 51 at a portion where the resist structure is finally unnecessary (for example, a portion where the black matrix 52 should not be formed), and a residue remains after development. There is a risk. That is, when the value of the transmittance T is close to Ith, the risk of the crosslinking reaction at the portion where the above structure is unnecessary and the residue retention may increase. In order to avoid this, it is desirable that the transmittance T of the transmission controller 36 be in a range that does not exceed 20% of the light intensity threshold Ith due to exposure. The contrast C2 when the transmittance T is 20% of the light intensity threshold Ith due to exposure is calculated by the equation (4).

  That is, the contrast is preferably 0.667 or more.

  Further, in consideration of the possibility that fluctuations (irradiation intensity fluctuations, in-plane nonuniformity of development, etc.) that may occur in the exposure step and the subsequent development step may occur, in order to obtain a better yield, the transmission control unit 36 It is more preferable that the transmittance T of 10% or less is 10% or less of the exposure amount threshold value Ith. The contrast C1 when the transmittance T is 10% of the exposure amount threshold value Ith is calculated by the equation (5).

  That is, the contrast is more preferably 0.818 or more. Then, as is clear from the above equations (4) and (5), these preferable contrast values do not depend on the Ith value.

  Further, in order to more directly evaluate the degree (fidelity) in which the transfer pattern 35 formed on the photomask 10 is reflected on the transfer target 51, a simulation is performed to form the transfer pattern 35 on the transfer target 51 by proximity exposure. The transfer image of the transfer pattern 35 is obtained, and the difference in shape between the obtained transfer image and the transfer pattern 35 is quantified and calculated as the difference S.

  The difference S corresponds to the area where the shape of the transfer pattern 35 on the photomask 10 and the shape of the transfer image formed on the transfer target 51 are different. The difference S is defined by the equation (6). The closer the difference S is to 0, the more faithfully the pattern on the photomask 10 is transferred to the transferred body 51, which is the better fidelity.

S = S1 + S2 (6)
Here, S1 becomes an area forming the black matrix 52 if the transfer pattern 35 of the photomask 10 is faithfully transferred, but in the transfer image obtained by the simulation, the light intensity is equal to the exposure amount threshold value Ith. Since it does not satisfy the requirement, it means the area of the region that does not form the black matrix 52.

  On the other hand, S2 is an area that does not form the black matrix 52 if the transfer pattern 35 of the photomask 10 is faithfully transferred, but in the transfer image obtained by the simulation, the light intensity exceeds the threshold value Ith, and the black matrix It means the area of the region forming 52.

  That is, S1 and S2 can be considered as the absolute values of the errors (deviations) on the minus side and the plus side from the faithful transfer, respectively, and the sum thereof is evaluated here. The numerical values of S1 and S2 were quantified by calculating the number of pixels in the above-mentioned deviation when output to 680 pixels square and multiplying this by u of the pixel unit area.

  FIG. 7 shows the influence on the transferred image when the proximity gap G is 100 μm and the phase shift amount of the transmission controller 36 is changed for the transfer pattern 35 having the shape of FIG. 1 and the dimensions of Table 1. It is shown by the numerical value of the difference S and the distribution of the shape differences (FIGS. 7B to 7F) by the simulation. Specifically, the transmittance of the transmission control unit 36 is set to 0.03 (3%), and the phase shift amount of the transmission control unit 36 is set to 0, 90, along with Comparative Example 1 of the binary mask in which the transmission is zero. The distribution of the difference S and the shape difference corresponding to the difference S for each case of 180 and 270 degrees is obtained. The Ith here was set so that the portion corresponding to the narrow black matrix 52 (the portion corresponding to the width D of the transparent portion 37 in FIG. 1) on the transferred body 51 was 6 μm.

  With respect to the shape (a) of the transfer pattern 35, the distribution of the shape difference for calculating the above S and the numerical value of S that quantifies it are as follows. Compared to Comparative Example 1 of (b) (binary mask, hereinafter also simply referred to as “binary”) and Reference Example 1 of (c) (halftone mask without phase shift, hereinafter also referred to as “HTM without phase difference”) In Example 1 of (f) in which the amount of phase shift is larger than 180 degrees, the numerical value of the difference S is the lowest and the fidelity is excellent.

  Reference example 3 shown in (e) in which the so-called halftone type phase shift mask having a phase shift amount of 180 degrees (hereinafter also referred to as “180 degree PSM”) is used as the transmission control section 36 is a comparative example shown in (b). Fidelity was lower than the binary mask of 1.

  The above tendency can be visually recognized from the distribution of the shape differences in FIG. 7. That is, in the photomask 10 of the present embodiment, by setting the phase shift amount of the transmission control unit 36 to a value exceeding 180 degrees, a transfer image superior to any conventional photomask can be obtained. But it became clear.

  Generally, in the proximity exposure method, the proximity gap is set to a predetermined value (for example, 100 μm), but it is realistic to set the distance from the transfer target 51 to this numerical value over the entire surface of the photomask 10. Is impossible to. For example, in the large-sized photomask 10 for a flat panel display, since the deflection due to its own weight occurs during the proximity exposure, the proximity gap may differ between the center of the photomask 10 and the outer edge thereof. Alternatively, a more complicated in-plane distribution (variation) of the proximity gap may occur due to a holding mechanism that applies a weight to the photomask 10 for the purpose of reducing the deflection.

  Therefore, FIG. 8 shows the result of studying the fidelity when the proximity gap G is 150 μm in the above simulation. In this case, since the proximity gap of 150 μm is unintentionally caused by the in-plane distribution or the like, the exposure amount threshold value is the value of Ith derived at 100 μm, which is the intentionally set predetermined proximity gap value. To use.

  According to FIG. 8, as in FIG. 7, the difference in shape is small in the photomask 10 of Example 2 shown in (f) as compared with the binary mask shown in (b) and the 180 degree PSM shown in (e). , Shows excellent fidelity.

  From the above, when a phase shift film is applied to the photomask 10 for proximity exposure to obtain an improvement in resolution due to the phase shift effect, the phase shift amount is established in the projection exposure method. It has been found that the 180 degree phase shift that occurs is not always optimal. That is, it has been found that the phase shift action used in the proximity exposure method exhibits more excellent fidelity when the phase shift amount exceeds 180 degrees. Particularly, in this case, it was found that the shape stability of the transferred image was remarkably excellent with respect to the variation of the proximity gap G. This point can also be understood from the small difference between Example 1 and Example 2 (that is, the difference in the difference S between FIG. 7F and FIG. 8F).

  Next, a more detailed optical simulation of the fidelity of the obtained transferred image is shown.

  In the following optical simulation, in the transfer pattern 35 of FIG. 1, when the phase shift amount φ and the transmittance T change, the phase shift amount φ and the transmittance T of the transmission controller 36 and the contrast of the transferred image. The correlation between Co and the difference S is examined.

  FIG. 9 is an explanatory diagram illustrating a method of displaying the simulation result. The simulation is performed by variously changing the combination of the phase shift amount φ and the transmittance T of the transmission control unit 36. In FIG. 9, the horizontal axis represents the phase shift amount φ (degree), and the vertical axis represents the transmittance T. Each rectangular frame whose boundary is indicated by a broken line shows each simulation condition.

  A portion K surrounded by a thick frame indicates a binary mask in which the transmittance T of the transmission controller 36 is 0, that is, the transmission controller 36 does not transmit light. The L portion surrounded by a thick frame indicates an HTM having no phase difference, because the phase shift amount φ of the transmission control unit 36 is 360 degrees, that is, 0 degree. The M part surrounded by a thick frame shows 180 degree PSM. The N portion surrounded by a thick frame shows the transmission control unit 36 in which the phase shift amount φ exceeds 180 degrees and is less than 360 degrees. In the following description, the photomask 10 including the transmission control section 36 corresponding to the N section is also referred to as an overshift angle phase shift mask.

  In the simulation, the exposure conditions were applied to a broad wavelength range including light having wavelengths of 313 nm, 334 nm, and 365 nm (intensity ratio 0.25: 0.25: 0.5) as exposure light. These are the main peak components below the i-line in the radiation spectrum of the high-pressure mercury lamp, which are applicable to the production of the black matrix 52 and the like and which are compatible with the photosensitive region of the negative resist. The transmittance T and the phase difference φ match a predetermined value for each wavelength due to the simulator characteristics. The proximity gap G is 100 μm.

  The transfer pattern 35 of the photomask 10 is the same as that described with reference to FIG. 7.

  Then, in this simulation, the values of the contrast Co and the difference S under each of the simulation conditions described above were calculated and associated with each rectangular frame indicated by the broken line in FIG. 9.

  10 to 12 are explanatory views for explaining the simulation result. FIG. 10 shows a case where the proximity gap G is 100 μm, and the portion surrounded by a thick line is an HTM having the same transmittance (0.03) and the same phase difference S due to the overshift angle phase shift mask. An area smaller than the 180 degree PSM and smaller than the binary is shown.

  That is, the area within the thick line is an area in which the transfer fidelity of the overshift angle phase shift mask is superior to that of binary, HTM without phase difference, and 180 degree PSM.

  FIG. 11 shows the result of a simulation performed under the same conditions as in FIG. 10 except that the proximity gap G was set to 150 μm. The portion surrounded by a thick line indicates a region where the fidelity of the overshift angle phase shift mask is superior to that of binary, HTM without phase difference, and 180 degree PSM, based on the same criteria as above.

  Generally, when the proximity gap G becomes larger than the set value, the deterioration of the transferred image tends to be remarkable. This point can be understood from FIGS. 7 and 8. However, according to the overshift 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, a high transfer with stable fidelity is obtained as compared with the existing photomask. It turns out that it shows sex.

  The area surrounded by the alternate long and short dash line in FIG. 12 represents the union of the parts surrounded by the thick lines in FIGS. In other words, when the proximity gap G is either 100 μm or 150 μm, the fidelity of the overshift angle phase shift mask is higher than that of the other photomasks 10. Further, a portion surrounded by a thick line indicates a portion surrounded by a thick line, that is, a common set in both FIG. 10 and FIG. 11. That is, a region where the fidelity of the overshift angle phase shift mask is high is shown regardless of whether the proximity gap G is 100 μm or 150 μm.

  From FIG. 12, it can be seen that the overshift angle phase shift mask in which the phase shift amount φ of the transmission control unit 36 exceeds 180 degrees has a fidelity more advantageous than the existing photomask.

  Further, according to FIG. 10, it is understood that the fidelity at the proximity gap G is advantageous when the phase shift amount φ of the transmission controller 36 is 255 degrees or more.

  Further, according to FIG. 10, when the transmittance T of the transmission controller 36 is 0.06 or less, the selection range of the phase shift amount φ of the transmission controller 36 for obtaining good fidelity is wide.

  Further, according to FIG. 11, even when the proximity gap unintentionally widens due to in-plane distribution or the like, good fidelity is obtained in a wide overshift angle range in which the phase shift amount φ of the transmission controller 36 is 330 degrees or less. can get.

  Further, according to FIG. 10 to FIG. 12, when the phase shift amount φ of the transmission control unit 36 is 255 degrees or more and 330 degrees or less, there is an advantage that the fluctuation of the proximity gap G has little effect on the fidelity, and it is 270 degrees or more. Sometimes the benefits are more pronounced.

  Further, if the transmittance T is 0.06 or less, the selection range of the phase shift amount φ for obtaining advantageous fidelity is wide regardless of the variation of the proximity gap G.

  Furthermore, if the phase shift amount φ of the overshift angle phase shift mask is 270 degrees or more, the selection range of the transmittance T for obtaining advantageous fidelity is wide.

  Note that FIG. 13 shows the result of calculating the contrast Co of the transfer image formed on the transfer target 51. The W part surrounded by a thick frame is a region where the contrast Co is 0.667 or more (however, less than 0.818), and the V part surrounded by a thick frame is a region where the contrast Co is 0.818 or more. Is. That is, the region W is a preferable range according to the formula (4), and the region V is a more preferable range according to the formula (5).

  Therefore, in addition to the conditions of the preferable phase shift amount φ and the transmittance T that can obtain the above-mentioned advantageous fidelity, further considering the range of the advantageous contrast Co in FIG. 13, a more preferable transfer property can be obtained. You can see that you can get it.

  For example, in the overshift angle phase shift mask, when the phase shift amount φ of the transmission control unit 36 is 225 degrees or more, the range of the applied transmittance T for obtaining a transferred image with good contrast is widened, and the phase shift amount φ is It can be seen that when it is 270 or more, the advantageous effect of further spreading can be obtained.

Further, the value of the transmittance T is preferably 0.1 or less as described above, but in particular,
0.01 ≦ T ≦ 0.09
Then, in a wide range of the phase shift amount φ of the transmission controller 36, a transferred image with good contrast can be obtained.
0.01 ≦ T ≦ 0.08
If so, the advantage is more remarkable.

Furthermore,
T ≦ 0.05
If so, a more preferable contrast Co is obtained,
T ≦ 0.04
If so, the selection range of the phase shift amount φ of the transmission control unit 36 is high in order to obtain a preferable contrast.

[Second Embodiment]
FIG. 14 shows a case where the design shape of the transfer pattern 35 of the photomask 10 is changed from that of the first embodiment. That is, the transfer pattern 35 of the photomask 10 has a parallelogram repeating pattern instead of a rectangular pattern. For example, the design is performed when the shape of the sub-pixel of the flat panel display is a parallelogram.

  In FIG. 14, the transmission controller 36 is a parallelogram having a base length C, a height B, an acute angle portion of 45 degrees, and an obtuse angle portion of 135 degrees. The transmission control units 36 are arranged in a matrix at intervals of D in the height direction and E in the direction along the bottom. The transfer pattern 35 of this embodiment is the same as that of the first embodiment except for the design change of these patterns, and the dimensions A to E are the same as those shown in Table 1. And

  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 onto the transfer target 51. This is the black matrix 52 in the ideal state. However, when the transfer pattern 35 shown in FIG. 14 is actually subjected to proximity exposure, the transfer image on the transfer target 51 is deteriorated in shape due to light diffraction and interference.

  Here, FIGS. 16 and 17 show the results of the same optical simulation as that performed in FIGS. 7 and 8 when the transfer pattern 35 shown in FIG. 14 is subjected to proximity exposure.

  That is, with respect to the transfer pattern 35 of FIG. 14, the transfer image and the difference S when the phase shift amount of the transmission control unit 36 is changed, where D is 6 μm and the proximity gap G is 100 μm, are shown in FIG. )-(E). Specifically, the transmittance of the transmission control unit 36 is set to 0.03 (3%), and the phase shift amount of the transmission control unit 36 is set to 0, 90, and Comparative Example 4 of the binary mask in which the transmission ratio is zero. The difference S is calculated for each of 180 and 270 degrees. Also here, the light intensity of Ith was standardized so that the width of the narrow black matrix 52 (the portion corresponding to D of the transfer pattern 35) was 6 μm. The collimation angle for proximity exposure was 2.0 degrees. The simulation conditions were the same as those in the first embodiment.

  Further, FIG. 17 shows the result of simulation under the same conditions as in FIG. 16 except that the proximity gap G is 150 μm.

  16 and 17, it can be seen that the transfer fidelity of the overshift angle phase shift masks of Example 3 and Example 4 is superior due to the value of the difference S as compared with the binary mask and 180 degree PSM. . Further, according to FIG. 16, when the proximity gap G is 100 μm, the fidelity of the HTM having no phase difference is slightly better than that of the third embodiment, but according to FIG. 17, when the proximity gap G is 150 μm, it is performed. The numerical value of the difference S in Example 4 becomes more excellent. Further, it can be understood from Examples 3 and 4 that when the proximity gap G that is different depending on the in-plane position is formed in the proximity exposure, the variation amount of the difference S is small due to the variation of the proximity gap G. This point is very significant in maintaining the in-plane uniformity of the transferred pattern, particularly in the manufacture of flat panel displays.

  18 to 20 are explanatory views for explaining the results of the same simulation as in FIGS. 9 to 11 described above.

FIG. 18 shows a case where the proximity gap G is 100 μm, and in the part surrounded by a thick line, the fidelity of the overshift angle phase shift mask is superior to that of binary, HTM without phase difference, and 180 ° PSM. Indicates the area.
That is, the area in the bold line is an area in which the difference S in the overshift angle phase shift mask is smaller than binary and smaller than both HTM having the same transmittance and no phase difference and 180 degree PSM.

  FIG. 19 shows the result of a simulation performed under the same conditions as in FIG. 18, except that the proximity gap G was set to 150 μm. The portion surrounded by a thick line shows a region where the fidelity of the overshift angle phase shift mask is superior to that of binary, HTM without phase difference, and 180 degree PSM.

  The area surrounded by the alternate long and short dash line in FIG. 20 represents the union of the parts surrounded by the thick lines in FIGS. 18 and 19. That is, when the proximity gap G is either 100 μm or 150 μm, the region where the fidelity of the overshift angle phase shift mask is high is shown. Further, the portion surrounded by the thick line indicates the portion surrounded by the thick line, that is, the common set in both FIGS. 18 and 19. That is, a region where the fidelity of the overshift angle phase shift mask is high is shown regardless of whether the proximity gap G is 100 μm or 150 μm.

  From FIG. 20, it can be seen that the overshift angle phase shift mask in which the phase shift amount φ of the transmission control unit 36 exceeds 180 degrees has a fidelity more advantageous than existing photomasks. Further, it is understood that particularly good results are obtained when the phase shift amount φ is 300 degrees or more.

  Further, as in the first embodiment, it is possible to select a more favorable condition of fidelity by simultaneously considering the range in which the contrast Co is good according to FIG.

  As shown in Embodiments 1 and 2 described above, according to the overshift angle phase shift mask, the photomask 10 capable of performing photolithography with good fidelity can be provided by using the proximity exposure apparatus 50.

  Further, according to the above-described embodiment, even when the proximity gap G changes depending on the in-plane position of the photomask 10, it is possible to reduce the change in the shape (including CD) of the transferred image due to the change. The photomask 10 can be provided. In particular, in a large-sized photomask 10 used for a flat panel display, the deflection due to its own weight and the proximity gap G easily change due to the holding means of the exposure apparatus. is there.

  Further, according to the above-described embodiment, the photomask 10 capable of performing exposure with high fidelity can be provided by combining the resist using the negative photosensitive material and the high pressure mercury lamp.

  The composition and film thickness of the transmission control film that constitutes the transmission control unit 36 are determined in order to have a predetermined exposure light transmittance and a phase shift amount. It may be uniform, or one permeation control film may be formed by laminating films having different compositions or different film properties.

  However, as long as the effect of the present invention is not impaired, different films (light-shielding film, etching stopper film, etc.) may be additionally provided, and the film pattern of the additional film may be changed to the pattern of the transmission control film. It may be provided on the upper surface side or the lower surface side.

  In addition, an additional film pattern (for example, a light-shielding film pattern) may be provided on the outer peripheral side of the transfer pattern 35, and such an additional film pattern is used when the photomask 10 is exposed or handled. The referenced mark pattern may be formed.

  In common with the above two embodiments, the photomask 10 of the present invention can be manufactured by, for example, the following manufacturing method.

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

  Next, a photomask blank with a resist in which a resist film is formed on the transmission control film is prepared. The resist may be a positive type or a negative type, but a positive type is preferable.

  Then, the photomask blank with resist is patterned. Specifically, a drawing device such as a laser drawing device is used to perform drawing with predetermined pattern data and develop. Further, using the resist pattern formed by development as a mask, the transmission control film is subjected to dry or wet etching to form a transfer pattern 35. Then, the resist pattern is peeled off.

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

  The material of the permeation control film can be, for example, a film containing Si, Cr, Ta, Zr, etc., and an appropriate one can be selected from these compounds.

  As the Si-containing film, a compound of Si (such as SiON) or a transition metal silicide (such as MoSi, TaSi, or ZrSi) or a compound thereof (oxide, nitride, carbide, oxynitride, oxynitride carbide, or the like) is used. be able to.

  As the Cr-containing film, a Cr compound (oxide, nitride, carbide, oxynitride, carbonitride, oxynitride carbide) can be used.

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

That is, the transfer step includes a step of preparing the above-mentioned overshift angle phase shift mask and a transfer step of exposing the transfer pattern 35 onto the transfer object 51 by exposing the transfer mask 35 with the proximity exposure apparatus 50. Then, it is a method of manufacturing an electronic device for a flat panel display, in which proximity exposure having a proximity gap of 50 to 200 μm is applied.

  The application of the photomask 10 can be suitably used for manufacturing the black matrix 52 or the black stripe, but is not limited thereto. However, the photomask of the present invention can be particularly suitably used for the purpose of forming a three-dimensional structure made of a photosensitive material on a transferred material. This is because it is extremely significant that excellent fidelity can be obtained in the shape of the three-dimensional structure formed by the transmission control section surrounded by the closed line and the translucent section surrounding the transmission control section. is there.

  Further, the present invention can be preferably applied to a transfer pattern including a so-called dense pattern in which unit patterns at a distance that optically affect each other are regularly repeated, such as a line-and-space pattern. .

The technical features (components) described in each embodiment can be combined with each other, and by combining, new technical features can be formed.
The embodiments disclosed this time are to be considered as illustrative in all points and not restrictive. The scope of the present invention is defined not by the above meaning but by the scope of the claims, and is intended to include meanings equivalent to the scope of the claims and all modifications within the scope.

10 Photomask 21 Transparent Substrate 35 Transfer Pattern 36 Transmission Control Section 37 Translucent Section 50 Proximity Exposure Device 51 Transfer Target 52 Black Matrix 56 Transfer Target (Glass Substrate)
57 light source 58 illumination system

Claims (16)

A photomask for proximity exposure, comprising a transfer pattern formed by patterning a transmission control film formed on a transparent substrate, comprising:
The transfer pattern has a transmission control section in which a transmission control film is formed on the transparent substrate, and a translucent section exposing the transparent substrate,
The said transmission control part is a photomask which has a phase shift amount over 180 degrees with respect to the exposure light which exposes the said photomask. A photomask for proximity exposure, comprising a transfer pattern formed by patterning a transmission control film formed on a transparent substrate, comprising:
In a photomask for proximity exposure with exposure light having a wavelength in the wavelength range of 313 to 365 nm,
The transfer pattern has a transmission control section in which a transmission control film is formed on the transparent substrate, and a translucent section exposing the transparent substrate,
The said transmission control part is a photomask which has a phase shift amount over 180 degrees with respect to the light of wavelength 365nm.   The photomask according to claim 2, which is used for exposing a negative photosensitive material.   The photomask according to claim 1, wherein the transmission control unit has a transmittance of exposure light of 10% or less.   The photomask according to claim 1, wherein the transfer pattern has a linear light-transmitting portion having a width of 3 to 10 μm.   The photomask according to claim 1, wherein the transfer pattern forms a linear pattern having a width of 10 μm or less on the negative photosensitive material on the transfer target.   The transfer pattern has a repeating pattern in which the transmission control unit and the light transmitting unit are regularly arranged, and the repeating pitch of the repeating pattern is 10 to 35 μm. Photomask described in one.   The transfer pattern has a repeating pattern in which the transmission control section and the light transmission section are regularly arranged, and the transmission control section has a shape surrounded by a closed line. The photomask according to any one of 1 to 3.   The photomask according to claim 1, wherein the transfer pattern has a repeating pattern in which the transmission control units are regularly arranged, and the transmission control units are quadrangular.   The photomask according to claim 1, wherein the transmission control unit has a phase shift amount of 255 degrees or more with respect to the exposure light.   The photomask according to claim 1, wherein the transmission control unit has a phase shift amount of 300 degrees or more with respect to exposure light.   The photomask according to claim 1, wherein the transmission control unit has a phase shift amount of 330 degrees or less with respect to the exposure light.   The photomask according to claim 1, wherein the transfer pattern is a black matrix or a black stripe forming pattern.   The photomask according to claim 1, wherein the transfer pattern is formed by patterning only the transmission control film on the transparent substrate. A step of preparing the photomask according to claim 1.
A transfer step of exposing the photomask by a proximity exposure device and transferring the transfer pattern to a negative photosensitive material film formed on a transfer target;
Have
In the transfer step, a method for manufacturing an electronic device for a flat panel display, wherein proximity exposure with a proximity gap set in a range of 50 to 200 μm is applied. A method for producing a photomask for proximity exposure, comprising a transfer pattern formed by patterning a transmission control film formed on a transparent substrate, comprising:
A step of preparing a photomask blank on which the transmission control film is formed on the transparent substrate;
A patterning step of patterning the transmission control film to form the transfer pattern;
Have
The transfer pattern has a transmission control section in which the transmission control film is formed on the transparent substrate, and a translucent section exposing the transparent substrate,
The transmission controller has a transmittance of 10% or less and a phase shift amount of more than 180 degrees with respect to the exposure light for exposing the photomask.
Photomask manufacturing method.

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