JP2006195330A - Method for manufacturing photomask for display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing photomask for display panel, capable of easily forming an ultraviolet ray shielding film in a large area without using a vacuum filming apparatus and, therefore, capable of manufacturing a large-area photomask for display panel at a low cost. <P>SOLUTION: The method for manufacturing photomask for display panel includes: a process of forming a coating film 2 by applying a paste consisting essentially of an organometallic compound of a noble metal on a glass substrate 1; a process of forming a metal film 3 which is prepared as the ultraviolet ray shielding film by baking the coating film 2 in the air environment and has a film thickness of the extent of 0.08 to 0.5μm; and a process of patterning the metal film 3, wherein the ultraviolet ray shielding film is formed on the glass substrate 1 independent of a vacuum filming process. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method of manufacturing a photomask used for film formation when manufacturing a display panel such as a plasma display panel known as a thin, lightweight display device having a large screen.

  In recent years, a flat panel display device using a plasma display panel, a liquid crystal panel, or the like has attracted attention as a large-screen, thin display device, and development of further higher definition and larger size is being promoted.

  In these flat panels, electrodes and structures are patterned on a substrate such as glass. As a patterning method, a screen printing method, a photolithography method, or the like is used. However, a photolithography method is mainly used because of a demand for higher definition of the pattern and a request for pattern accuracy. In the photolithography method, a region exposed to ultraviolet rays and a region not exposed to ultraviolet rays are formed on an electrode or structure formed on a substrate by a thin film formation method or a thick film formation method using a photomask. These are removed by etching to form a necessary shape pattern.

Conventionally, as a method of manufacturing such a photomask, a metal film such as a chromium film is formed on a polished glass substrate by a vacuum thin film forming method such as a sputtering method, and this chromium film is developed and etched into a predetermined pattern. An example is disclosed in which an ultraviolet transmission pattern without a chromium film and an ultraviolet shielding pattern with a chromium film are formed on a substrate (see, for example, Non-Patent Document 1).
Story of photomask technology 1996 Industrial Research Committee P13-P17

  However, in such a photomask manufacturing method, an ultraviolet shielding metal film is formed by a vacuum thin film forming method such as a sputtering method. Therefore, due to the demand for larger screens for image display, larger photomasks are also required for larger flat panels, but larger vacuum film deposition equipment has resulted in increased equipment costs and photomask manufacturing. It has the problem of increasing costs.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a method of manufacturing a photomask for a display panel that can form an ultraviolet shielding metal film of a large area photomask at low cost.

  In order to achieve the above object, a method for manufacturing a photomask for a display panel according to the present invention includes a step of applying a paste mainly composed of an organometallic compound to a glass substrate to form a coating film, and the coating film in an atmospheric atmosphere. A step of forming the ultraviolet shielding film by baking, and a step of patterning the ultraviolet shielding film.

  According to such a manufacturing method, since the ultraviolet shielding film can be easily formed in a large area without using a vacuum film forming apparatus, a photomask for a large area display panel can be manufactured at low cost. . Organometallic compounds of precious metals are materials that have been applied to ceramics and glass tableware, and have been used for decorative purposes by firing precious metal thin films, but by selecting and combining their precious metal compositions, they are thin films. Therefore, it is possible to effectively shield ultraviolet rays and easily pattern the ultraviolet shielding film with high accuracy.

  Further, the organometallic compound is an organometallic compound containing at least one of nickel, chromium, and copper. The coating film is fired in an air atmosphere to form a metal oxide thin film, and then fired in a reducing atmosphere. As in the case of precious metals, the process can include a process, and the ultraviolet shielding film can be easily processed with high accuracy and easily, and the ultraviolet shielding film can be effectively formed at low cost without using a vacuum film forming apparatus. .

  Furthermore, in order to improve the adhesion between the glass substrate and the ultraviolet shielding film, it is desirable to include at least one organometallic compound of silicon, boron, lead, vanadium, and bismuth in the paste. According to such a method, the adhesion between the glass substrate and the ultraviolet shielding film can be improved.

  According to the present invention, since the ultraviolet shielding film can be easily formed in a large area without using a vacuum film forming apparatus, a photomask for a display panel having a large area can be manufactured at a low cost.

  The method for manufacturing a photomask for a display panel according to the present invention is particularly effective for manufacturing a photomask when manufacturing a plasma display panel or a liquid crystal panel that requires a large screen size.

  First, a plasma display panel that is an object of an embodiment of the present invention will be described with reference to the drawings. FIG. 4 is a schematic view showing a plasma display panel, FIG. 4 (a) is a plan view, and FIG. 4 (b) is a cross-sectional view taken along line AA in FIG. 4 (a). In the plasma display panel 50, the front plate 51 and the back plate 60 are arranged to face each other, and the outer peripheral portion is sealed by a sealing member 61. Exhaust pipes 62 are provided at the corners of the back plate 60 for exhausting the internal discharge space and enclosing the discharge gas. The exhaust pipe 62 is sealed after the discharge gas is sealed.

  FIG. 5 is a partial cross-sectional perspective view showing the internal structure of the plasma display panel 50. The plasma display panel 50 includes a front plate 51 and a back plate 60 that are disposed to face each other. The front plate 51 has a structure in which a transparent electrode 53, a bus electrode 54, a black stripe 55, a dielectric layer 56, and an MgO dielectric protective layer 57 are sequentially formed on a glass substrate 52. The back plate 60 has a structure in which an address electrode 64 and a base dielectric layer 65 are formed on a glass substrate 63, a partition 66 is formed thereon, and a phosphor layer 67 is formed between the partitions 66. ing. In the discharge space 68 between the front plate 51 and the back plate 60, for example, a discharge gas, which is a mixed gas of neon (Ne) -xenon (Xe), is sealed at a pressure of 53200 Pa (400 Torr) to 79800 Pa (600 Torr). ing. By discharging the discharge gas between the electrodes to generate ultraviolet rays and irradiating the phosphor layer 67 with the ultraviolet rays, a color image can be displayed.

A method for manufacturing the front plate 51 will be described. The glass substrate 52 is formed of a glass material having a thickness of about 2.8 mm that can withstand a heat treatment process included in the process of forming the bus electrode 54, the black stripe 55, the dielectric layer 56, and the like. The formed high strain point glass is used. A solid film is formed on the glass substrate 52 by sputtering or the like using a material such as ITO or SnO _2, and then a patterned transparent electrode 53 is formed by using a photolithography method or the like. The bus electrode 54 on the transparent electrode 53 is formed by patterning using a photolithography method or the like by applying a photosensitive material containing a conductive material such as Ag. Next, the black stripes 55 are similarly formed by patterning using a photolithography method using a glass material containing a black pigment. Next, the dielectric layer 56 is formed of a PbO—B ₂ O ₃ —SiO ₂ glass material. As a method for forming the dielectric layer 56, there are a screen printing method, a die coating method, and the like. Next, MgO is deposited by a method such as sputtering to form the dielectric protective layer 57, and the front plate 51 is completed.

Next, a method for forming the back plate 60 will be described. Using a photosensitive material containing a conductive material such as Ag, an address electrode 64 is patterned by photolithography on a glass substrate 63 having substantially the same specifications as the glass substrate 52 of the front plate 51. Next, the base dielectric layer 65 is formed of a PbO—B ₂ O ₃ —SiO ₂ based glass material. Next, the partition 66 is formed of an aggregate such as Al ₂ O ₃ and a glass frit material. As a method for forming the partition 66, various methods such as a sand blast method and a photolithography method can be applied. Next, red, green, and blue phosphor pastes are sequentially applied between the barrier ribs 66 by a printing method, a dispenser method, a line jet method, or the like to form the phosphor layer 67, thereby completing the back plate 60. .

  Thereafter, the front plate 51 and the back plate 60 are overlapped and sealed with a sealing member 61 at the outer periphery thereof to form a discharge space 68 inside. A gas in the discharge space 68 is exhausted through the exhaust pipe 62, and a mixed gas of neon and xenon is sealed at a pressure of about 66.5 kPa to complete the assembly process, and a plasma display panel 50 that displays a color image Become.

  As described above, when the plasma display panel 50 is manufactured, patterning is performed using a photolithography method when forming at least the transparent electrode 53, the bus electrode 54, the address electrode 64, the partition wall 66, and the like. At that time, a solid film such as each electrode is exposed using a photomask, and then patterned to form an etching process.

  FIG. 6 is a process explanatory view showing a photomask manufacturing method used when manufacturing a conventional plasma display panel having a screen size of up to about 60 inches. As shown in FIG. 6, a glass substrate polishing step for polishing the surface of the glass substrate 40, a metal Cr film formation step for forming an ultraviolet shielding film such as a metal chromium film 41 on the polished glass substrate 40, and a metal Cr film 41 The photomask 44 is completed through a resist coating patterning process in which a resist 42 is applied and a pattern is drawn, a Cr film etching resist stripping process in which the metal Cr film 41 is etched and the resist 42 is stripped. Here, the ultraviolet shielding film such as the metal chromium film 41 is formed to a thickness of several thousand angstroms by a vacuum film forming method such as sputtering. In addition, when a thin film is formed by such a vacuum film forming method, the surface properties of the substrate greatly affect the quality of the formed thin film, so the glass substrate is polished to remove irregularities and defects on the glass substrate. It is necessary to keep it.

  In any case, in order to form the ultraviolet shielding film by such a vacuum film forming method, a large-scale apparatus such as a vacuum exhaust apparatus, a vacuum chamber, or a material evaporation source is required. The glass substrate size of the plasma display panel photomask having a screen display size of 80 inches or more is about 2100 mm × 1500 mm. Therefore, the apparatus cost of the vacuum film forming apparatus increases, and the manufacturing cost of the photomask also increases.

(First embodiment)
FIG. 1 is a process explanatory view showing a method for manufacturing a photomask for a display panel in the first embodiment of the present invention. As shown in FIG. 1, the photomask manufacturing method according to the first embodiment of the present invention includes a step of cleaning a glass substrate (step 1) and a step of forming a coating film of an organometallic compound on the glass substrate (step). 2) A step of baking the coating film in the atmosphere (step 3), a step of drawing a pattern on the metal film formed by baking (step 4), and a step of etching the metal film (step 5).

  In the present invention, the ultraviolet shielding film is formed not by a vacuum film forming method but by a thick film forming method in the atmosphere. Specifically, in step 2, a material mainly composed of a noble metal organometallic compound (metal resinate) such as gold (Au), silver (Ag), platinum (Pt), or palladium (Pd), and a resin material Thus, a coating film forming paste is prepared, and a coating film 2 having a thickness of 3 to 20 μm is formed on the glass substrate 1 by a screen printing method or the like. As a method of forming the coating film 2, in addition to screen printing, a die coating method, a spray method, or the like can be applied, and an organic metal is used so that a physical property value such as paste viscosity is optimized according to each coating film forming method. The compounding ratio of compound and resin material is adjusted. In the first embodiment of the present invention, a noble metal is used as the metal of the organometallic compound. This is because a metal oxide is not formed as an ultraviolet shielding film in the subsequent firing step in the atmosphere, and is pure. This is because the shielding effect of ultraviolet rays can be enhanced by forming the metal film. Further, the organometallic compound of the noble metal is not limited to one kind, and a plurality of organometallic compounds may be mixed and used.

  Next, in step 3, the coating film 2 is baked at 500 to 800 ° C. in the atmosphere in the baking furnace 7. The organic substance of the organic metal compound in the coating film 2 and the resin in the resin material burn, only the metal component of the organic metal compound is deposited, and the metal film 3 having a film thickness of about 0.08 to 0.5 μm is a glass substrate. 1 is formed. Since these metal films 3 have a large ultraviolet shielding effect, that is, low ultraviolet transmittance, they can be used as an ultraviolet shielding film for a photomask. Further, the film thickness of the metal film 3 can be varied by adjusting the film thickness of the coating film 2 in step 2 or the blending ratio of the organometallic compound in the paste. However, the ultraviolet shielding effect is great.

  Next, in step 4, a photosensitive resist film 4 is applied to the metal film 3, a photomask pattern is drawn using a laser drawing apparatus or the like, and a resist film 4 having a necessary pattern is formed.

  Next, in step 5, the metal film 3 in a region where the resist film 4 is not present is removed by etching and the resist film 4 is peeled off, whereby the photomask 5 is completed. Therefore, the photomask 5 is composed of the glass substrate 1 and the metal film 3 formed in a necessary pattern, and the metal film 3 portion serves as an ultraviolet shielding film, and the region 6 on the glass substrate 1 where the metal film 3 is absent is ultraviolet light. It becomes a transmission area. These patterns are formed into patterns such as the transparent electrode 53, the bus electrode 54, or the black stripe 55 of the front plate 51 that constitutes the plasma display panel 50 described above, the address electrode 64 that constitutes the back plate 60, the partition wall 66, and the like. Is formed.

  As described above, in the embodiment of the present invention, the metal film 3 having the ultraviolet ray shielding effect is formed by forming the coating film 2 mainly composed of the organometallic compound on the glass substrate 1 and baking them in the air. Can be formed. Therefore, the metal film 3 can be easily formed without the need for a vacuum film forming apparatus or the like, and even if the screen size of a plasma display panel or the like becomes a large plate such as 80 inches or 100 inches, it can be manufactured. A photomask to be used can be realized at low cost. Steps 4 and 5 are processes for patterning the ultraviolet shielding film.

  In the above description, only the precious metal organometallic compound and the resin material are used as the paste. However, a small amount of silicon (Si), boron (B), lead (Pb), vanadium (V), bismuth (Bi). By mixing at least one of the organic metal compounds, the adhesion between the glass substrate 1 and the metal film 3 is improved to form a strong metal film 3, and a photomask 5 with excellent pattern accuracy is realized. be able to. However, if the amount of the organometallic compound added is too large, the adhesion becomes stronger. However, after pattern processing, the residue of the metal oxide remains on the trace after the ultraviolet shielding film is removed, which may deteriorate the ultraviolet transmittance. Therefore, the amount added must be controlled.

(Example)
FIG. 2 is a diagram showing the ultraviolet transmission characteristics of an ultraviolet shielding film manufactured by the method for manufacturing a photomask for a display panel in the first embodiment of the present invention. In FIG. 2, the horizontal axis indicates the wavelength, and the vertical axis indicates the transmittance. In this embodiment, an organometallic compound of gold (Au) is used as the organometallic compound, and several percent of the organometallic compound of platinum (Pt) is contained. Further, as shown in the figure, the thickness of the metal film as the ultraviolet shielding film was manufactured by changing the paste coating thickness of two types of 0.16 μm and 0.24 μm.

  As shown in FIG. 2, it can be seen that the transmittance increases as the wavelength becomes longer, and that the transmittance is smaller as the film thickness increases. In manufacturing a display panel or the like, a low-pressure mercury lamp is generally used as a light source used as an exposure source, and the ultraviolet wavelength is 365 nm i-line, 405 nm h-line, and 436 nm g-line. The actually used ultraviolet region is indicated by a broken line region in FIG. Therefore, the ultraviolet shielding film of the photomask needs to be a shielding film having a shielding effect with respect to these wavelengths.

  As shown in FIG. 2, in the metal film of the present example, a chromium (Cr) metal thin film formed by a conventional vacuum film forming apparatus that exhibits a sufficient ultraviolet shielding effect in the broken line region has a transmittance of 0. It has the same characteristics as that of 04%, and a sufficient ultraviolet ray shielding effect can be obtained even when the film thickness is 0.16 μm, and the material cost can be reduced.

  In this embodiment, some organometallic compound of platinum (Pt) is mixed with organometallic compound of gold (Au). The reason for this is that the closer to silver luster is better than the so-called gold luster as the metal film, and the ultraviolet shielding effect is superior, and in the case of gold alone, the transmittance increase phenomenon occurring near 400 nm is suppressed. is there.

(Second Embodiment)
FIG. 3 is a process explanatory view showing a method of manufacturing a display panel photomask according to the second embodiment of the present invention. As shown in FIG. 3, the method of manufacturing a photomask according to the second embodiment of the present invention includes a step of cleaning a glass substrate (step 1) and a step of forming a coating film of an organometallic compound on the glass substrate (step). 2) A step of baking the coating film in the atmosphere (step 3), a step of baking in a reducing atmosphere (step 4), a step of drawing a pattern on the formed metal film (step 5), and etching the metal film It is comprised by the process (step 6) to perform. Therefore, in the second embodiment of the present invention, a firing process (step 4) in a reducing atmosphere is further added to the above-described first embodiment.

  Specifically, in step 2, a paste for forming a coating film is prepared from a resin material and a material mainly composed of an organometallic compound (metal resinate) such as nickel (Ni), chromium (Cr), or copper (Cu). Then, the coating film 10 having a film thickness of 3 to 20 μm is formed on the glass substrate 1 by a screen printing method or the like. As a method of forming the coating film 10, in addition to screen printing, a die coating method, a spray method, or the like can be applied, and an organic metal is used so that a physical property value such as paste viscosity is optimized according to each coating film forming method. The compounding ratio of compound and resin material is adjusted.

  Next, in step 3, the coating film 10 is baked in the baking furnace 11 in the atmosphere at 500 to 800 ° C. The organic substance of the organic metal compound in the coating film 10 and the resin in the resin material burn, the metal component of the organic metal compound is deposited, and the metal oxide film 12 having a thickness of about 0.08 to 0.5 μm is formed on the glass substrate. 1 is formed. Generally, metals such as nickel (Ni), chromium (Cr), and copper (Cu) are easily oxidized, so that the coating film 10 after firing in the atmosphere becomes a metal oxide film 12. These metal oxide films 12 have a small ultraviolet shielding effect, that is, a high ultraviolet transmittance. Further, the film thickness of the metal oxide film 12 can be varied by adjusting the film thickness of the coating film 10 in Step 2 and the blending ratio of the organometallic compound in the paste.

  Next, in step 4, the metal oxide film 12 having a small ultraviolet shielding effect is baked in a reducing atmosphere in a firing furnace 13 in order to make the metal film having a large ultraviolet shielding effect. By baking in a reducing atmosphere, oxygen can be removed from the metal oxide film 12, and the metal film 14 having a large ultraviolet shielding effect can be obtained.

  Steps 5 and 6 of the subsequent processes are the same as Steps 4 and 5 of the first embodiment, and thus description thereof is omitted. However, according to the second embodiment of the present invention, Compared with the embodiment, the raw material cost can be reduced, and the photomask 15 for a display panel can be manufactured at a lower cost.

  Note that a small amount of silicon (Si), boron (B), lead (Pb), vanadium (V), or bismuth (Bi) at least one organometallic compound is mixed in the paste used when forming the coating film 10. By doing so, it is possible to improve the adhesion between the glass substrate 1 and the metal film 14 to form a strong metal film 14 and realize a photomask 15 having excellent pattern accuracy.

  In the above description, the plasma display panel has been described as the display panel, but it can be applied as a photomask when manufacturing a liquid crystal panel, an EL panel, an SED panel, or the like.

  As described above, according to the present invention, since an ultraviolet shielding film can be easily formed in a large area without using a vacuum film forming apparatus, it is useful for a display panel having a large area useful for manufacturing various display panels. It can be applied to the manufacture of a photomask.

Process explanatory drawing which shows the manufacturing method of the photomask for display panels in the 1st Embodiment of this invention The figure which shows the ultraviolet-ray transmission characteristic of the ultraviolet-ray shielding film manufactured with the manufacturing method of the photomask for display panels in the 1st Embodiment of this invention Process explanatory drawing which shows the manufacturing method of the photomask for display panels in the 2nd Embodiment of this invention Schematic showing the plasma display panel Partial cross-sectional perspective view showing the internal structure of the plasma display panel Process explanatory drawing which shows the manufacturing method of the photomask used when manufacturing the conventional plasma display panel of the screen size to about 60 inches.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Glass substrate 2,10 Coating film 3,14 Metal film 4 Resist film 5,15 Photomask 6 Area | region without a metal film 7,13 Baking furnace 12 Metal oxide film

Claims (4)

Applying a paste mainly composed of an organometallic compound to a glass substrate to form a coating film; baking the coating film in an air atmosphere to form an ultraviolet shielding film; and patterning the ultraviolet shielding film The manufacturing method of the photomask for display panels including the process to carry out. The method for producing a photomask for a display panel according to claim 1, wherein the metal of the organometallic compound is a noble metal. The organometallic compound is an organometallic compound containing at least one of nickel, chromium, and copper, and includes a step of firing in a reducing atmosphere after firing a coating film in an air atmosphere. Item 2. A method for producing a photomask for a display panel according to Item 1. 4. The method for producing a photomask for a display panel according to claim 2, wherein the paste contains at least one organometallic compound of silicon, boron, lead, vanadium, and bismuth.

Images