JP4033196B2 - Photolithographic mask, thin film forming method, and liquid crystal display manufacturing method - Google Patents

Description

In the present invention, a photolithographic mask provided with a plurality of transmission regions, a thin film forming method using the photolithographic mask, and thin film patterns having different film thicknesses are formed on a glass substrate by a single process. method of manufacturing a liquid crystal display device.

  In recent years, with an increase in screen size of liquid crystal display devices such as a liquid crystal display and an increase in manufacturing process efficiency, the scale of a photolithography process for forming a thin film pattern on a glass substrate used in a liquid crystal display device has been increasing. When carrying out such a large-scale photolithography process, since the production efficiency is poor in the exposure by the stepper, a large-sized photomask that can efficiently expose a large substrate material is used. Yes.

  Also, due to diversification of liquid crystal modes and the like, a multilayer film structure formed by performing a photolithography process a plurality of times is required, but such an increase in the number of photolithography processes is an increase in process time. It is a problem. For example, it is necessary to form a multi-stage thin film pattern on a glass substrate such as a multi-stage color filter or multi-gap for forming a reflection / transmission combined type liquid crystal. Such an increase in the photolithography process hinders cost reduction and lead time reduction.

  As a means for solving the above-described problem, there is a method using a halftone mask in which a plurality of transmission regions having different light transmittances are provided on one mask substrate. This method adjusts the amount of light to be exposed on a substrate on which a thin film pattern is formed (hereinafter referred to as a target substrate) by providing transmission regions having different light transmittances on a photomask, A thin film pattern having a film thickness of 1 mm is formed by a single photolithography process. According to this method, since the photosensitive material on the target substrate is exposed with exposure light having different intensities, a thin film pattern having a multistage structure can be formed in one photolithography process.

  In the case of using the above-described halftone mask, interference between diffracted lights occurs at the boundary between transmission regions having different light transmittances. When the interference between the diffracted lights weakens each other, a portion exposed to weaker light is generated in the thin film pattern formed on the target substrate to generate a film reduction step. For this reason, when a halftone photomask is used, it is difficult to satisfactorily form a multistage thin film pattern by a single process due to the influence of the above-described interference of diffracted light.

  In order to eliminate the influence of such diffracted light, it is preferable to perform the photolithography process with the photomask and the target substrate in close contact as much as possible. However, if contact occurs between the photomask and the target substrate due to the influence of the deflection of the photomask or the waviness of the target substrate, problems such as contamination and scratches on the photomask and poor film formation occur. When contaminated, it is necessary to replace the photomask each time, resulting in poor production efficiency and cost disadvantages. Therefore, exposure is performed with a predetermined gap between the photomask and the target substrate. There is a need. Furthermore, with the increase in the size of the substrate material described above, the flexure of the photomask and the undulation of the target substrate tend to be larger, and it is necessary to further increase the distance between the photomask and the target substrate. This is a cause of increasing the influence of the diffracted light on the thin film pattern formed on the target substrate in combination with the higher definition of the mask pattern.

Therefore, the present invention can be applied to a large-scale photolithography process, and a thin film pattern having a multistage structure can be efficiently and satisfactorily formed by a single process, and the above-described film reduction step is used for the shape of the thin film pattern. there is provided a thin film forming method using a photolithographic mask and the photolithographic mask may be, production of liquid crystal display device further formed a thin film pattern on a substrate by carrying out such a thin film forming method It aims to provide a method.

  In order to solve the above-described problem, the present invention provides a photolithographic mask provided with a light-shielding region and a plurality of transmission regions, and an arbitrary phase difference of light transmitted through adjacent transmission regions among the plurality of transmission regions. A thin film pattern having a level difference equal to or greater than the number of transmissive regions is formed.

  Moreover, the thin film formation method which concerns on this invention performs exposure using the mask for photolithography mentioned above. In this thin film formation method, exposure is performed by arranging a thin film formation target and a photolithography mask with an interval of 50 μm or more and 500 μm or less.

Further, the production method of engaging Ru liquid crystal display device of the present invention, a thin film forming method described above was carried out at a photolithography process to form a thin film having a multi-stage structure on the thin film formation target.
Here, the photolithography mask of the present invention used in the thin film forming method of the present invention and the method of manufacturing a liquid crystal display device has a phase difference of light transmitted through adjacent transmissive regions among a plurality of transmissive regions having different transmittances. Is arbitrarily set to be in the range of (−1 / 4 + 2m) π or more and (1/4 + 2m) π or less (where m is an integer).

In the photolithography mask, the thin film forming method, and the liquid crystal display manufacturing method according to the present invention described above, the phase difference of the light transmitted through the adjacent transmission region is (−1 / 4 + 2 m) π or more, and (1/4 + 2 m) π. By restricting within the following range (where m is an integer), the reduction in exposure light intensity due to the interference of diffracted light is suppressed, so that the film reduction step generated in the thin film pattern is suppressed to be small. Therefore, according to the photolithography mask, the thin film forming method, and the liquid crystal display manufacturing method according to the present invention, a thin film pattern having a multistage structure is formed in a single process without causing film formation defects.

In addition, according to the thin film forming method and the liquid crystal display manufacturing method according to the present invention, the photolithography process is performed with a relatively large space of 50 μm or more and 500 μm or less between the photolithography mask and the thin film formation target. Therefore, even when a large-sized substrate is used, contact between the substrate material and the photomask can be prevented, and a large-scale photolithography process can be handled.

According to the photolithographic mask of the present invention, the phase difference of light transmitted through the plurality of transmission regions is in the range of (−1 / 4 + 2m) π or more and (1/4 + 2m) π or less (where m is an integer). By arbitrarily setting, the thin film pattern having a complicated structure having a fine step, for example, can be satisfactorily formed by a single process.

According to the thin film forming method and the liquid crystal display manufacturing method according to the present invention, a thin film pattern having a complicated structure can be easily obtained by a single process by using the photolithographic mask having the above-described configuration. In addition, the productivity of the liquid crystal display device can be improved and the cost can be reduced.

According to the thin film forming method and the liquid crystal display manufacturing method according to the present invention, by using the above-described photolithographic mask, a relative distance of 50 μm or more and 500 μm or less is provided between the photolithographic mask and the thin film formation target. Exposure is performed with a large interval. Therefore, according to the thin film forming method and the liquid crystal display manufacturing method according to the present invention, the contact between the photolithographic mask and the thin film formation target is prevented, and a large-scale substrate material is used. This can correspond to a photolithography process.

  Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.

  As shown in FIGS. 1 and 2, the photomask 1 has a light shielding part 3 having a transmittance of 0% or close to 0% on the transparent mask substrate 2 and a transmittance of the exposure light L of 0%. A region having three different transmittances, specifically, one light-shielding portion, that is, a semi-transmissive portion 4 set between 100% and 100%, and a transmissive portion 5 in which the transmittance of the exposure light L is 100% or close to 100%. A region and two transmissive regions are formed. Here, the transmittance of each region is the relative transmittance of the above-described light-shielding portion 3, semi-transmissive portion 4 and transmissive portion 5 when the transmittance of the exposure light L of the mask substrate 2 itself is 100%. . As shown in FIG. 1, the photomask 1 is formed by applying a negative photosensitive material on a thin film forming substrate 11 in a photolithography process to form a resist layer 12 and exposing the resist layer 12 to form a thin film pattern 13. Used in getting. Here, the description is based on the premise that a negative photosensitive material is used, but the present invention can also be applied to a positive photosensitive material by changing the relationship between light shielding and transmission of the photomask 1.

  The light shielding unit 3 forms a light shielding film on the mask substrate 2 so that the transmittance of the exposure light L is 0% or a value close to 0%. As the light shielding film, for example, a thin film with low transmittance such as metallic chromium is used.

  The semi-transmissive portion 4 reduces the transmittance by forming a semi-transmissive film, for example, a low-transmittance film or multilayer film by absorption on the mask substrate 2. For example, an oxide film such as chromium oxide is used as the semi-permeable film. Note that the transmissivity of the translucent portion 4 is arbitrarily set according to the thickness of the thin film formed in the photolithography process, the type of the photosensitive material, and the like.

  The transmissive portion 5 has an opening pattern in which a thin film is not formed on the mask substrate 2 like the light shielding portion 3 and the semi-transmissive film 4 described above.

  When the photolithography process is performed using the photomask 1 having the above-described configuration, the photomask 1 and the thin film formation substrate 11 are arranged with a certain interval (hereinafter, this interval is referred to as a print gap). The When the print gap is larger than a certain size with respect to the size of the photomask 1, the exposure light transmitted through the semi-transmissive portion 4 and the transmissive portion 5 is strongly diffracted, that is, light wraps around. When affected by such diffraction, as shown in FIG. 3, the diffracted light (La ′ and Lb ′) of the exposure light La that passes through the adjacent semi-transmissive portion 4 and the exposure light Lb that passes through the transmissive portion 5. ) Interfere with each other at the boundary portion, and as a result of this interference, exposure light Lc which is a superposition of diffracted light is generated. The light intensity of the exposure light Lc does not decrease when the interference between the diffracted light La ′ and the exposure light Lb ′ strengthens each other, but the light intensity decreases when they weaken each other. When the intensity of the exposure light Lc is weakened due to the influence of diffraction, a film-reducing step is formed in the resist layer 12 where the exposure light Lc has been irradiated during development after exposure, resulting in poor film formation. Further, depending on the sensitivity characteristics of the resist material, the residual film illuminance may be lower than the limit illuminance, which may result in film missing, that is, a state where there is no residual film, or a partial or defective peeling of the resist layer 12.

  In the photomask 1, the film thickness and refractive index of the semi-transmissive film formed on the semi-transmissive portion 4 are defined, and the above-described interference of diffracted light at the boundary between the semi-transmissive portion 4 and the transmissive portion 5 weakens each other. I am trying not to. Hereinafter, verification by simulation regarding the definition of the thickness and refractive index of the semi-transmissive film in the semi-transmissive portion 4 will be described.

  First, a photomask 1 in which the transmittance of the semi-transmissive portion 4 is set to 50% of the transmissive portion 5 is assumed. In such a photomask 1, if there is no phase shift between the light transmitted through the semi-transmissive portion 4 and the light transmitted through the transmissive portion 5 (φ = 0), the diffracted light strengthens each other. As shown in the characteristic diagram of FIG. 4, the intensity of the exposure light Lc at the boundary between the semi-transmissive portion 4 and the transmissive portion 5 does not decrease. In such a case, on the thin film forming substrate 11, as shown in FIG. 5, a good thin film having no step difference in film thickness reduction at the portion irradiated with the exposure light Lc at the boundary portion between the semi-transmissive portion 4 and the transmissive portion 5. A pattern 13 is formed.

  On the other hand, when the phase of the light transmitted through the semi-transmissive portion 4 and the light transmitted through the transmissive portion 5 is shifted by a half wavelength, that is, when the phase difference φ = π, the diffracted light interferes with each other and is weakened. Therefore, as shown in the characteristic diagram of FIG. 6, the intensity of the exposure light Lc at the boundary portion between the semi-transmissive portion 4 and the transmissive portion 5 decreases. In such a case, on the thin film forming substrate 11, as shown in FIG. 7, a portion with an extremely thin film thickness is formed due to the reduction of the film in the portion irradiated with the exposure light Lc, and a film formation defect occurs.

8A to 8D (d in each drawing indicates the film thickness of the semi-transmissive film formed in the semi-transmissive portion 4). The exposure light La transmitted through the semi-transmissive portion 4 and the transmissive portion 5 are shown in FIG. The phase difference with the transmitted exposure light Lb is changed, and the intensity distribution of the exposure light L at that time is shown. For each exposure light L shown in FIGS. 8, 4, and 6, the film reduction step generated in each thin film pattern was examined. As shown in FIG. 4 (phase difference φ = 0) and FIG. In each of the cases of φ = 1 / 8π) and FIG. 6B (phase difference φ = 1 / 4π), the generated step was small and could be used, but FIG. 6 (phase difference φ = π) In each case of FIG. 8C (phase difference φ = 1 / 2π) and FIG. 8D (phase difference φ = 3 / 4π), the level difference was large and a film formation defect occurred. As a result, when the phase difference φ between the light transmitted through the semi-transmissive portion 4 and the light transmitted through the transmissive portion 5 is within the range of the following formula (1), a good thin film pattern 13 without film formation failure is obtained. Can be determined.

  In order to eliminate the film formation failure as described above, in the photomask 1, the phase difference φ of the light transmitted through each of the semi-transmissive portion 4 and the transmissive portion 5 is expressed by the above formula (1) on the thin film forming substrate 11. The optical characteristics of the semi-transmissive film formed in the semi-transmissive portion 4 are set so as to be within the range. Below, the example of a setting of the refractive index and film thickness of the semi-permeable film formed in the semi-transmissive part 4 is shown. In the following description, it is assumed that the semi-transmissive film formed in the semi-transmissive portion 4 is not affected by multiple reflection.

If the rotation of the phase when the light transmitted through each of the semi-transmissive part 4 and the transmissive part 5 travels through the film thickness d of the semi-transmissive film formed in the semi-transmissive part is φ ₁ and φ ₂ , The phase difference is expressed by the following equation (2).

  When the phase difference expressed by the above formula (2) is an integral multiple of the wavelength (formula (3) shown below), the respective phases coincide (φ = 0), and an odd multiple of the half wavelength (shown below) In the case of equation (4), the phase is reversed (φ = π).

Therefore, by forming the semi-transmissive film formed in the semi-transmissive part 4 so as to satisfy the same phase condition as shown in the above formula (3), the film reduction at the boundary part between the semi-transmissive part 4 and the transmissive part 5 is achieved. A good thin film pattern 13 with small steps can be obtained on the thin film forming substrate 11. Specifically, when the refractive index of the semi-transmissive film is n ₂ and the film thickness is d, the refractive index and the film thickness such that the following expression (5) is satisfied with respect to the wavelength λ of light used for exposure. Design a semi-permeable membrane. In this case, n ₁ in the formula (5) is the refractive index of the air layer, but another permeable film may be formed in the transmissive portion instead of the air layer in order to adjust the phase difference.

  Therefore, in order to satisfy the condition shown in the above formula (1), the refractive index and film thickness of the semi-transmissive film are set so as to satisfy the following formula (6).

  Actually, the transmittance of the semipermeable membrane in the semipermeable portion 4 needs to be adjusted between 0% and 100% in accordance with the application. As a method for adjusting the transmittance, there are a method of manipulating the absorptivity (extinction coefficient) of the semi-transmissive film, a method of forming an interference filter by multiple reflection, and the like. Care must be taken to receive. In this case, since a deviation occurs from the condition shown in Expression (6), the film thickness, refractive index, and extinction coefficient of the semi-transmissive film are finally designed so as to satisfy the condition shown in Expression (1). If the absorption of the semi-transmissive film itself is sufficiently large when manipulating the absorptance, multiple reflected light can be ignored, and therefore the condition of equation (6) can be applied as it is without phase rotation. .

As described above, the photomask 1 in which the film thickness and refractive index of the semi-transmissive film formed in the semi-transmissive part 4 are regulated can suppress unnecessary steps due to the influence of diffraction and prevent the occurrence of film formation defects. it can. Such a photomask 1 can be used when the thin film pattern 13 having the shape shown in FIGS. 9 and 10 is formed by a photolithography process. The thin film pattern 13 as shown in FIG. 9 is applied when, for example, a protrusion 13a serving as a spacer for forming a cell gap in a liquid crystal display device and a flat portion 13b serving as a color filter or a flattening film are simultaneously formed. can do. Further, the thin film pattern 13 as shown in FIG. 10 is provided with a protrusion 13a serving as an alignment wall, a color filter, and a flat surface in a liquid crystal display device using a liquid crystal alignment mode using protrusions such as an ASM mode and an MVA mode. This can be applied to the case where the flat portion 13b to be a film, a spacer or the like is formed at the same time.

  Furthermore, in the photomask 1 described above, it has been described as having two types of transmissive regions, a semi-transmissive portion 4 and a transmissive portion 5, but a shape as shown in FIG. Specifically, the thin film pattern 13 having a three-stage structure can be formed. The thin film pattern 13 shown in FIG. 11 can be applied to the case where the first protrusion 13c and the second protrusion 13d serving as spacers and alignment walls are simultaneously formed on the flat portion 13e serving as a planarizing film. The photomask 1 is not limited to the thin film pattern having the two-stage structure or the three-stage structure described above, and thin film patterns having various shapes can be obtained by variously changing the conditions such as the number of transmission regions and transmittance. Can do.

  The above-mentioned regulation of the film thickness and the refractive index in the photomask 1 is intended to prevent unnecessary steps from being caused by the influence of diffraction by setting the phase difference within a certain range, but it is more complicated. When a pattern having a step or a pattern having a structure that emphasizes an edge is formed on the thin film forming substrate 11, conversely, the step formed by the influence of diffraction can be positively used. Specifically, the phase difference between the light transmitted through the semi-transmissive part 4 and the light transmitted through the transmissive part 5 is shifted and arbitrarily set to be outside the range of the above formula (1), and exposure at the boundary part is performed. By adjusting the intensity of the light Lc, the film reduction step formed at the boundary is used as the shape of the thin film pattern 13. In this way, by using the film reduction step to form the thin film pattern 13, a step higher than the transmission region provided in the photomask 1 can be formed. Such a photomask 1 can be used when the thin film pattern 13 having the shape shown in FIGS. 12 and 13 is formed by a photolithography process. The thin film pattern 13 shown in FIG. 12 can be shaped as shown in the figure by setting the transmittance itself of the semi-transmissive portion 4 to be substantially the same as that of the transmissive portion 5 and shifting only the phase by, for example, a half wavelength. Further, the transmittance of the semi-transmissive portion 4 is arbitrarily set so as to be different from that of the transmissive portion 5, and the wavelength of the exposure light that is transmitted through both is arbitrarily changed to form a thin film having a complicated shape as shown in FIG. It is also possible to form a film by a single process.

  A thin film forming method using the photomask 1 having the above-described configuration will be described below. In the present embodiment described below, a case where a thin film pattern 13 having a two-stage structure is formed on a thin film formation substrate 11 will be described.

First, as shown in FIG. 14A, a negative photosensitive material is applied on the thin film forming substrate 11 to form a resist layer 12. Then, alignment of the photomask 1 is performed with respect to the thin film forming substrate 11, and after the alignment, exposure light L is irradiated as shown in FIG. At this time, the photomask 1 is disposed with a print gap of 50 μm or more and 500 μm or less from the thin film formation target, specifically, the resist layer 12 formed on the thin film formation substrate 11. Then, it wash | cleans with a washing | cleaning liquid and removes an unexposed part, and as shown in the figure (c), the desired thin film pattern 13 is obtained. Although only the procedure for forming a thin film has been briefly described here, the conditions other than the print gap, such as the photosensitive material applied on the thin film forming substrate 11 and the cleaning liquid during cleaning, are the types of thin film to be formed, etc. According to the above, known materials, cleaning liquids, etc. can be appropriately selected and used.

  In the thin film forming method described above, various thicknesses can be obtained by changing the combination of the transmittance ratio between the semi-transmissive portion 4 and the transmissive portion 5 of the photomask 1 and the sensitivity characteristics of the photosensitive material applied on the thin film forming substrate 11. A thin film having a combination can be formed by a single process, and can be applied when the same material and a plurality of film thicknesses are required.

  In the thin film formation method described above, the exposure process is performed with a relatively large distance of 50 μm or more and 500 μm or less between the photomask 1 and the thin film formation target. Contact between the mask 1 and the thin film forming substrate 11 and the resist layer 12 formed thereon can be prevented, and a large-scale photography process can be handled.

  When the phase of the exposure light transmitted through the semi-transmissive portion 4 and the transmissive portion 5 of the photomask 1 is shifted by the same process as the thin film forming method described above, the level difference is greater than the region provided in the photomask 1. A pattern having a shape can be obtained.

A method for manufacturing a liquid crystal display device in which the above-described thin film forming method is performed in a photolithography process will be described. As shown in FIG. 15, the liquid crystal display device 20 is provided with color filters 21R, 21G, and 21B corresponding to the colors R, G, and B (hereinafter referred to as the color filter 21 when the colors are not distinguished). Further, a first substrate 24 on which a planarizing layer 22 made of an organic transparent resin and a counter electrode 23 made of a conductive thin film such as ITO are formed, a reflective electrode 25 that also functions as a reflector and a pixel electrode, ITO, etc. A second substrate 27 on which a transparent electrode 26 made of a conductive thin film is formed is disposed opposite to each other, and liquid crystal is injected therebetween. The liquid crystal display device 20 includes transmission filter portions 21Ra, Ga, Ba in which color filters 21R, 21G, 21B are formed one step higher than the transparent electrode 26, and reflection filters formed one step lower on both sides thereof. It has a two-stage structure having portions 21Rb, Gb, and Bb, and these transmission and reflection filter portions are integrally formed.

  Since the liquid crystal display device 20 includes the transmissive display structure that transmits light and the reflective display structure that does not transmit light, both transmissive display and reflective display can be performed. Thereby, for example, the display image recognition can be performed by the reflective display structure unit in a bright place around the surroundings, and the display image recognition can be performed by using the reflective structure unit mainly in the transmissive structure unit in the dark. Further, by forming the color filters 21 having different thicknesses for transmission and reflection, respectively, appropriate transmittance and chromaticity can be displayed.

  Although not shown in detail, the second substrate 27 includes a plurality of scanning lines arranged substantially parallel to each other, a plurality of reference signal lines arranged alternately and substantially parallel to the scanning lines, and A common wiring that connects the plurality of reference signal lines to each other and a thin film transistor (TFT) that is provided for each reflective electrode 25 and is a three-terminal switching element that selectively drives the reflective electrode 25 are provided.

  The liquid crystal display device 20 having the above-described configuration is subjected to the thin film formation method using the photomask 1 described above in the photolithography process, and the two-stage color filters 21R, 21G, and 21B are formed. In this photolithography process, a negative photoresist added with a pigment of a desired color is used, and color filters 21R, 21G, and 21B are formed for each color filter. First, a color resist to which a red pigment is added is applied to a predetermined thickness on the first substrate 24 and dried to form a red color resist film. Next, a predetermined region of the color resist film, that is, a region to be left as the color filter 21R is exposed from the surface side using the photomask 1, and the exposure region of the color resist film is cured. Then, the exposed color resist film is developed to remove the unexposed areas. At this time, the semi-transmissive portion 4 and the transmissive portion 5 of the photoresist 1 are formed with a semi-transmissive film in the semi-transmissive portion 4 so that the phases of the exposure light passing through each of them match, so It is possible to obtain a good two-stage pattern without film formation defects. Then, the remaining two-stage color resist film on the first substrate 24 is used as the color filter 21R. Thereafter, similar to the color filter 21R, a color resist to which a green pigment is added is applied and exposed and developed, and then a color resist to which a blue pigment is added is applied and exposed and developed to obtain a color filter. 21G and 21B are sequentially formed.

  As described above, by carrying out the thin film forming method using the photomask 1 in the photolithographic process when the liquid crystal display device 20 is manufactured, the two-stage structure for the transmission and reflection type liquid crystal display device is used. The reflective color filter can be formed in a single process. For this reason, the manufacturing method of the liquid crystal display device 20 described above reduces the number of steps and improves the production efficiency.

  In addition, according to the method of manufacturing the liquid crystal display device 10 described above, the photolithography process is performed with a relatively large space of 50 μm or more and 500 μm or less between the photomask 1 and the thin film formation target, and thus a large screen. Also in the manufacturing process of the liquid crystal display device, contact between the photomask 1 and the thin film forming substrate 11 or the resist layer 12 formed thereon can be prevented.

It is a figure for demonstrating the photolithographic process performed using the photomask to which this invention is applied. It is a bottom view of the photomask to which the present invention is applied. It is a figure for demonstrating the state of the transmitted light which permeate | transmits the said photomask. It is a characteristic view which shows the light intensity distribution of the transmitted light which permeate | transmits the said photomask. It is sectional drawing of the thin film pattern formed into a film by the light intensity distribution shown in FIG. It is a characteristic view which shows the light intensity distribution of the transmitted light which permeate | transmits the said photomask. It is sectional drawing of the thin film pattern formed into a film by the light intensity distribution shown in FIG. It is a characteristic view which shows the light intensity distribution of the transmitted light which permeate | transmits the said photomask. It is sectional drawing which shows the specific example of the thin film pattern formed into a film using the photomask which made the phase difference of a transmission part and a semi-transmission part correspond. It is sectional drawing which shows the other specific example of the thin film pattern formed into a film using the photomask to which this invention is applied. It is sectional drawing which shows the other specific example of the thin film pattern formed into a film using the said photomask. It is sectional drawing which shows the specific example of the thin film pattern formed into a film using the photomask which set the phase difference of a transmission part and a semi-transmission part arbitrarily. It is sectional drawing which shows the other specific example of the thin film pattern formed into a film using the photomask to which this invention is applied. It is sectional drawing for demonstrating the film-forming process of the thin film formation method concerning this invention. It is sectional drawing which shows schematic structure of the liquid crystal display device to which this invention is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photomask, 2 Mask substrate, 3 Light-shielding part, 4 Semi-transmission part, 5 Transmission part, 20 Liquid crystal display device

Claims (5)

In a photolithographic mask provided with a light shielding region and a plurality of transmission regions having different transmittances ,
Arbitrary so that the phase difference of the light transmitted through the adjacent transmissive region among the plurality of transmissive regions is in the range of (−1 / 4 + 2m) π or more and (¼ + 2m) π or less (where m is an integer). A thin film pattern having a level difference equal to or greater than the number of the transmissive regions is formed by using a film-reducing step set at a boundary between the adjacent transmissive regions . A light shielding region and a plurality of transmission regions having different transmittances are provided, and a phase difference of light transmitted through an adjacent transmission region among the plurality of transmission regions is not less than (−1 / 4 + 2 m) π, and is (¼ + 2 m). ) Exposure using a photolithographic mask arbitrarily set so as to be in the range of π or less (where m is an integer), and utilizing the film reduction step formed at the boundary between the adjacent transmission regions. And forming a thin film pattern having a level difference equal to or greater than the number of the transmissive regions. 3. The method of forming a thin film according to claim 2 , wherein the photolithography mask is arranged at an interval of 50 μm or more and 500 μm or less with respect to a thin film formation target. A light shielding region and a plurality of transmission regions having different transmittances are provided, and a phase difference of light transmitted through an adjacent transmission region among the plurality of transmission regions is not less than (−1 / 4 + 2 m) π, and is (¼ + 2 m). ) Less than π (where m is an integer), including a photolithographic process in which exposure is performed using a photolithographic mask arbitrarily set, and a film reduction that can be formed at the boundary between the adjacent transmission regions A method of manufacturing a liquid crystal display device, comprising using a step to form a thin film pattern having steps equal to or greater than the number of the transmissive regions. 5. The method of manufacturing a liquid crystal display device according to claim 4 , wherein the photolithography mask is arranged at an interval of 50 [mu] m to 500 [mu] m with respect to a thin film formation target.

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